Frequently Asked Questions (Page 1)
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Q. Differences Between Black Inks
Q. What's Great About Superior Ink?
Q. Bad Paper?
Q. Eliminating Calcium Buildup
Q. Press Virus
Q. Detecting Bad Printing Press Rollers
Q. Ink Buildup on Printing Press Blankets
Q. Complicated Roller Cleaning
Q. More Sheetfed Ink Drying Problems
From Star Bulletin, June, 1999
Q.: Why is it that all of a sudden I get a lot of toning and picture framing on my small press and even my large press has been having drying problems as well.
A.: You’re not alone in this. We have been seeing this problem in the vast majority of shops we hear from. In nearly all cases we solve all of the mentioned problems by the use of a more efficient roller cleaning system.
The natural tendency is to begin experimenting with fountain solution, but when printing press rollers are glazed or contaminated you must run excessive fountain solution to overcome scumming or toning. This then forces you to run too much ink to maintain density. Sheetfed ink then waterlogs or at the very least overemulsifies, thus destroying the body of the vehicle in the ink and rendering the driers useless.
It’s true that a different fountain solution may produce temporary relief, but as the glaze progresses the window of success becomes progressively narrower until nothing works without producing other side effects.
As an example, I can speak from our own experience here at Star in the production of this newsletter. When the rollers in our old A. B. Dick 360 are perfectly clean, any one of ten different fountain solutions will work satisfactorily. Of course, one may be slightly too wet while another may be a bit too dry, but they will all produce satisfactory work. When some bad paper goes through the press and chemicals from the paper find their way into the inking and dampening systems, the buildup of contamination starts to work its magic and several fountain solutions begin to fail. As the contamination progresses to glaze, the list narrows down to maybe one fountain solution that barely works and the ink may begin to print snowflaky solids.
After a ten minute decontamination the press is right back to its almost flawless performance!
If I persist in running the paper that contaminated the rollers, the problem will return just as quickly.
In one case the picture framing was severe after running perhaps 200 sheets of 11 x 17 recycled stock, and the rollers in the Crestline dampener began piling ink at the same time. By sheeting off most of the surface ink and changing paper, the dampener straightened right out and the picture framing went away after around 500 impressions.
The bottom line here is, there is some bad paper out there, and it comes from any or all paper mills, and it is constantly changing, so we must be prepared to keep our systems cleaner than ever before to avoid constant problems.
Star’s Press Diet© Roller Maintenance System was developed to clean this nasty stuff out of your rollers. Printers tell us that our system works, and it must be true because hundreds of customers in a ten state region continue to reorder our products time and again.
Don’t hesitate to call us at 303-423-6300 for more information.
From Star Bulletin, September, 1999
Q.: What can I do to prevent sheets from sticking to my blanket?
A.: The smoother the sheet, the more prone it is to stick to your blanket. Some offset printing blankets we used years back were very problematic in this regard. Today we have some high tech printing blankets that give phenomenal release while rendering extremely sharp and clean images.
If the sheet is pulling out of the grippers near the lead edge of the sheet, I would check that the cylinder grippers are holding the sheet tightly enough to pull it off the blanket. If the sheet is folded over four inches or more from the gripper edge, I would be suspicious that the delivery grippers are closing on the sheet too late. Both sets of grippers should be holding the sheet for around 1/8” of cylinder travel. This can be checked by removing the blanket and turning a sheet through the press by hand. Pull back on the tail of the sheet and see if it transfers into the delivery grippers smoothly. If it pulls out during the transfer, then it’s tune-up time.
If all is mechanically correct, check your pressures. Too much impression pressure can cause the sheet to stick to any offset printing blanket.
If everything checks out, but the problem persists, I would suggest trying one of our 9500 blankets. We have seen great results with this blanket. It is even in thickness or caliper, and runs easily with minimum pressures required for top quality printing. We have even eliminated streaks by simply changing to this blanket. We stock them for most small presses and many larger machines. Folks tell us that they really take a beating and last much longer than most offset printing blankets. Huxley Vertical
From Star Bulletin, September, 1999
Q.: What can I use to remove metallic ink residues from my rollers? No matter what I do it seems like there is always a slight residue.
A.: My first suggestion would be to change over to our Press Diet© roller Maintenance system to deep clean your printing press rollers every time. I will also say that it is normal for particles of metallic flakes to remain on printing press rollers even after a thorough cleanup. The only question is “How much is too much?” In general, the metallic flakes always look like a lot more than is actually there because they are so shiny against the dark surface of the roller.
If you can imagine how much of the surface of the roller is covered with the flakes, you will get an idea of how clean to clean your rollers. In general, the dirtiest roller would only have a five percent surface coating of particles, hardly enough to be visible on the next printing job. Consequently, you can usually ink up and run the next job with no worry whatsoever. After running several jobs you will see that the metallic flakes are all gone, absorbed into other inks and washed off with a normal washup.
Q.: Any time I have a problem and call one of our suppliers it seems that the information they give me contradicts what another person has told me. How can I know who to believe?
A.: This has been a persistent problem in our trade for many years, especially since the change in the late 1980’s to alkaline papers, followed by many, many other changes to supplies and chemicals used in the pressroom for decades. Star got into the supply business partly because we couldn’t seem to get any answers either. It got so bad that the printing of the Star Bulletin became a real project due to problems caused by the changes in the paper supply.
I don’t have all the answers, but you can bet I’ll go to great lengths to find out, then I’ll offer a valid explanation along with any product recommendations or techniques predicted to remedy the problem.
I believe in proving that what I say is true to the best of my knowledge, and I was a pressman for many years, so if you aren’t getting the straight scoop, feel free to give me a call at 303-423-6300.
From Star Bulletin, February, 2000
Q.: Why is it that certain ink colors never seem to match the Pantone® book nor the previously mixed batch no matter how careful we weigh and mix the colors?
A.: A color match consists of two different but related challenges. The first one is that the actual ink must match a previous batch. We evaluate this by putting a drop of each side-by-side on a piece of uncoated paper then drawing them both down with an ink knife. By holding the sheet up to the light, any slight variations can be detected.
The other challenge is the fact that presses print differently on different days. Add to that any concern about the job having been printed on another press last time, or the rollers were newer or older last time, and you can see that the variables are piling up rather quickly. Sheetfed printing ink also has a tendency to yellow over time, so tans and grays become another problem.
Now, let’s go back to the actual printing of the Color Book. I know that every job I have ever run had some color variation, so how about your formula book? It certainly has some variations; compare two books if a question arises. Some of the formulas may be flawed as well.
Many sheetfed inks have an excess of solvents to speed up the initial setting of the ink. Now add in some driers or tack reducers and your ink probably doesn’t match to start with, to say nothing of the “dryback” that will surely occur within the first hours after printing.
Now, let’s explore the addition of alcohol to your fountain solution. Alcohol has a tendency to “wash out” most colors, requiring the running of a heavier-than-normal film of ink to achieve the desired color. Certain colors containing opposite mixing colors will dramatically shift color due to the differing strengths of the mixing colors. An example of this might be Pantone 464. It is made with Rubine Red, Process Blue and Yellow. When run heavy, the Blue and Red darken up disproportionately when compared to the Yellow, so the color shifts dramatically. This color also dries back considerably on certain papers, and has a severe tendency toward yellowing.
Glazed or contaminated printing press rollers will make color matches virtually impossible due to the fact that you will have to run excessive water and may not be able to achieve the required ink density regardless of how much you run on the rollers.
I don’t know if I have a positive answer to a solution to your dilemma, but above are the reasons for the problems. By accurately weighing your inks every time and double checking everything, you will normally achieve the same mixture every time. Keeping good rollers, properly adjusted and cleaned, will assure consistent printing results, and such problems will be held to a minimum.
We mix tons of sheetfed ink here at Star, so if you have persistent problems with a specific color, feel free to call us and find out what we do about it.
From Star Bulletin, April, 2000
Q.: I know you have published this information before, but can you please explain blanket pressures so we can better understand what we’re trying to accomplish?
A.: There are two styles of offset printing blanket construction: Conventional and Compressible. In the United States we prefer compressible offset blankets probably due to the roughness of our papers and because we tend to run shorter runs on many different papers and the compressible offset blanket offers a wider window of error when establishing pressures.
There seems to be a lot of confusion because foreign-made presses give us operator’s manuals that specify settings and pressures often in metric. And we are not normally informed as to whether the numbers specified are for a compressible blanket.
So, let’s just go back to the basic rules of proper pressures from years ago. (This would apply primarily to sheetfed presses, as certain web presses might have different requirements). Rule one states that a conventional offset printing blanket needs from 2 to 3 thousandths (.002” to .003”) of an inch of squeeze to print properly. Rule two continues to tell us that if we’re using a compressible offset printing blanket we must add an additional 3 to 4 thousandths (.003” to .004”) to that dimension to print properly. By taking the averages of these two specifications, we arrive at a squeeze of .006”. This figure is true regardless of the size of your press.
So, how do we arrive at that dimension easily?
On older presses it was very easy. We simply measured the plate, packing and blanket then did the math. Then we would double check it with a packing gauge if the press ran on bearer pressure. If we didn’t have a packing gauge, we simply inked up the plate then put the plate and blanket together on pressure then measured the stripe. The width of stripe that always worked best with a compressible blanket was 3/8”, which is equivalent to a .006” squeeze on presses with cylinders up to around 10” in diameter.
On many of today’s presses that don’t have bearers, we still do the math, then double check our results by again doing the stripe test. Here’s where the complications come in; how does your particular press provide for such a test?
On some, there is a code that you type in to snap the pressures on then off. On others you must fool the machine to put it on impression, then let the plate and blanket get inked up so you can check stripes like a roller stripe.
Once you have established that the plate-to-blanket pressures are correct, the bottom or impression pressure is adjusted best by results produced. That is, by looking at the sheet and judging your results. A gloss sheet may print perfectly by adjusting your pressure setting to exactly the thickness of the sheet, while a rough, textured sheet may require you to squeeze it beyond the zero thickness setting. Don’t become fixated on your micrometer, adjust for results on every job. An old timer taught me this concept back in the early 1960’s by asking me how far I push down the gas pedal to go 50 mph. I told him I didn’t know, because it depends on a lot of conditions. He just smiled and walked away.
Yes, you can definitely print with less than the ideal pressure, but you’ll have to run excessive ink and water, color control will be a bit touchy, and drying problems will begin to surface on certain jobs.
From Star Bulletin, November, 1999
Q.: What are the differences between process black, Pantone® neutral black and dense black?
A.: Sheetfed process black inks are made to print as part of a process set. The tack is normally quite high, as most process printing is done with dark-to-light color sequence on multi-color sheetfed presses. A fourth-down black is also made for certain jobs where it must overprint an opaque or metallic color. The color is also balanced to the requirements for process work; not too blue nor too yellow.
Pantone neutral or mixing black is made to a specific color and strength so grays will match correctly when the formula calls for a large percentage of white. Again, not too red, yellow or blue.
Sheetfed dense black ink is formulated to print a deep, bluetone black, and is made with a greater pigment load as well as perhaps 5% of a blue similar to reflex blue. The blue overpowers the natural brown cast of the black pigment and appears blacker to our eyes. It can be used as a process ink if no grays or tans that must be matched appear in the pictures in the process job.
Some printers add a 50% screen of process blue to a black solid when running a process job. The blue serves to maximize the opacity, or covering power, of the black ink.
From Star Bulletin, November, 1999
Q.: I’m a temporary pressman and I have been seeing a lot of Star’s Superior Ink in shops around town. What’s so great about it?
A.: The word “great” is a very subjective word. One person’s definition of a “great” sheetfed ink might be one that is so cheap it comes in a plastic bag instead of a can, while somebody else would prefer an ink that costs a little more but does the job on the first try.
The best answer to this question would be for me to describe the attributes of Superior Printing Inks as I see them, then you can decide for yourself whether or not it would be a “great” ink for you.
When I was running presses for a living it seemed as though I always had to have all brands of sheetfed ink “hissing” on the rollers in order to print dark enough to match the color book. I worried about offset all day long on every job, even on uncoated, and thus had to apply spray powder to even simple jobs as a precaution. I also had to add lots of drier and fight jobs, to get them back through the press without picking or smearing. Large solids on a pocket folder using dark blues or greens always had me reaching for the aspirin and antacid bottles. I remember life being very tough in the pressroom and every job was a challenge.
I used to look at fancy annual reports from large multinational corporations and wonder how in the world anybody could ever print such a difficult job. Other pressmen I knew expressed the same opinion. Many jobs I ran won awards, but only I could know how difficult they had been to produce.
The first time I ran Superior Printing Ink was in 1993, on our old A. B. Dick 360. The dense black was so black that when dry it read around 265 on a densitometer. The trouble was that I ran it like I was used to running ink, with it hissing on the rollers. After readjusting my way of thinking, I ran one issue of Star Bulletin at a more correct density of 170 and was amazed at how little ink I had to carry on the rollers and the handful of sheets where I had temporarily shut off the spray wasn’t offset.
So I guess what I like about Superior Printing Ink is that it’s strong enough to carry a thin film and still get up to color density without screens becoming mottled, but not so strong that hickeys become a problem. This makes running a press a very simple proposition from my point of view.
With a thin film of ink, less water needs to be run to keep the plate clean, so drying is vastly improved, less offset spray powder means fewer problems on subsequent runs, as well as a cleaner shop.
I don’t know if the Made in America attribute is an important issue with most people, but Superior Printing Ink Co. uses as many American made ingredients in their inks as possible, including soy bean oil as well as other vegetable oils. Most Superior Printing Inks are laser safe as well.
Probably my current favorite thing about Superior Printing Ink is that when we mix Pantone Colors for our customers, the colors virtually always match right on…even the grays and tans that can be problematic at times.
I don’t know if this answers your question, but if not, feel free to give me another call at 303-423-6300.
From Star Bulletin, January, 2000
Q.: I keep hearing a lot of people blame everything on “bad paper.” What’s the real problem?
A.: I understand the denial, because the paper mills are huge manufacturers that try to impart a sense of infallibility of their product. Their stance is that everything else is at fault.
Rather than point any fingers, let me just give you my personal experience with a particular batch of paper. I won’t tell the brand because paper mills manufacture paper for each other so there’s no way to know who the real culprit is. I will say, though, that Colorado has been a test market for many years as well as a dumping ground for marginal products (makereadies, if you will).
One issue of the Star Bulletin ran so well that I couldn’t believe how things were running. Then the next issue ran so badly I thought somebody had sabotaged my press. A full day of trying many different fountain solutions accomplished nothing. I decontaminated the ink and water rollers and still the problem persisted. When I ran out of that batch of paper, things smoothed out within 500 sheets. The toning and picture framing went away, the ink piling on the Crestline rollers went away and the printing looked sharper.
During the pressrun I stopped to take a phone call and took a piece of the paper with me to write a note and my pen quit working. A second pen did the same. Coincidence? Maybe. But read on. I came to believe that I did indeed have a bad batch of paper so I changed to 20# copy bond and haven’t had any problems since. That is, until I decided to use up that questionable paper in my laser printer. About 100 copies of miscellaneous sheets printed and my toner cartridge roller became contaminated with something and started printing with terrible streaks and blind areas.
Now I believe it for sure. I hated to waste that five bucks worth of paper, but I can’t afford to save it anymore, so it’s in the dumpster, where some bum can eventually find it and ruin his pens as well. My toner cartridge is still half full, and will just barely print simple reports.
So, what to do about it? Keep your printing press rollers immaculately clean. This will give you the best shot at being able to diagnose a paper contamination problem. If setup sheets run fine but the job doesn’t, think about it. If different fountain solutions don’t change anything, it’s something else.
If you’re tired of all the finger pointing among your different suppliers, Give us a call. That’s why we got into the supply business in the first place; we couldn’t get any information from any of the big boys, so we had to find out on our own when things became so bad that we could barely print the Star Bulletin!
Star’s Press Diet© cleaning system easily deals with any sort of contamination problem, but if your printing press rollers are becoming re-contaminated within a hundred sheets, you’re gonna have a very long day.
The Press Diet© system also includes excellent fountain solutions, sheetfed inks and offset printing blankets that have been proven to produce top quality results.
From Star Bulletin, January, 2000
Q.: I recently tried to run a job with a rectangular solid next to a screen. I couldn’t keep the solid up to color without the screen filling in. What can I do?
A.: Judging by the sheets you sent me, it looks like a simple matter of ink fountain control. The solid requires much more ink than the 20% screen next to it, so excess ink is moved by the oscillators into the area of the screen, which is then overinked.
The easiest way to run this job is to turn your ink fountain sweep (rotation) up to maximum and turn in the keys until a thin film is transferred to the ink ductor. By regulating the ink film thickness with the fountain keys, a fine film is transferred into the inker in proportion to how much is being consumed by a given area of the press. Any excess ink that ends up in the area of the screen will be removed by the ink fountain roller and returned to the fountain and this will prevent overinking in the area of the screen.
The theory behind this is that offset printing ink does, indeed, travel both directions. When an area of the ink fountain is set for a given amount, it will put out exactly so much ink until such a time that the amount on the ductor matches that on the fountain roller, when ink will just sit there and not transfer either way. When an area of the ink fountain is carrying less ink than the ink ductor, then ink will travel back into the fountain.
A way to better understand this concept would be to load the ink rollers full of ink; really glob it on until the rollers barely turn. Then tighten in the ink fountain keys and engage the ink ductor. After idling for five or ten minutes with the ink fountain turning full sweep and the ductor doing its job, the rollers will be lightly inked again and the fountain will be full.
When running any ordinary job, with each contact of the ink fountain roller a minute amount of ink is transferred into the inker. What isn’t consumed by being printed to the sheet eventually is moved toward the outer edges of the printing press rollers by the oscillating rollers, where it is then slowly transferred back into the ink fountain, carrying lint, dust and hickeys with it. With a very short sweep, this excess ink just sits there on the ends of the rollers and eventually becomes waterlogged. This “stale ink,” as it is called may eventually work its way back into the image area and end up in the printed job, possibly causing drying problems.
At the very least, “stale ink” loses its ability to flow properly when it becomes waterlogged and then forces you to run an excessive amount of ink to achieve a color match. The end result is normally a severe drying problem or chalking on certain papers.
Also, there are certain extreme cases where because of the layout of the job or color of the ink, you’ll just have to make two plates and run the screen by itself to avoid overinking.
From Star Bulletin, March, 2000
Q: What do the different colors of blankets mean?
A: According to an anonymous source at one of the printing blanket manufacturers, it is mostly a marketing tool. If I try to sell you another blue blanket, it will be perceived as the same old blanket with a new name. If it’s a totally different color, then it’s easier to believe that it’s a different product.
The color also might be used in a huge shop to designate some particular special requirement. For instance, our 9600 blanket is purple, and would most likely be used for running a job with extremely fine screens on high gloss stock. The 9500 blanket is pink, and is very smash resistant so it is probably the printing blanket of choice for 99% of the jobs you would ever run. In a huge shop the foreman might tell the press crew to “Change to the purple blankets for that Acme job.” It avoids confusion in trying to remember numbers.
The manufacturer can make any offset printing blanket any color. The color of the thread on the cloth back also tells the manufacturer something, as in the case of a warranty claim where several different brands of blanket are blue.
It’s also easier for a customer to tell a supplier, “Send me out 6 more of those pink blankets for my A. B. Dick 9800, and a pair of the blue ones for my Hamada.”
In summary, the color has absolutely nothing to do with performance. A certain offset printing blanket that performs poorly and just happens to be a certain color may just be an old product that has outlived its usefulness, and can’t cope with the rougher surface finishes on today’s papers.
From Star Bulletin, February, 2000
Q.: We have been having a lot of slow drying lately. My pressman says it’s normal to need 2-3 days for jobs to dry. Is this correct?
A.: Absolutely not! Under normal circumstances, any job should be dry enough to cut overnight at the longest. Many jobs should be dry enough to cut in 4 hours or less, depending on the paper and coverage.
It is very common to have drying problems when mechanical or chemical deviations interfere with the driers incorporated into sheetfed inks. The three most common culprits are contaminated & glazed offset printing rollers, improper fountain solution mixtures and incorrect pressures.
Printing rollers are not able to efficiently carry a thin film of ink if a coating of glaze covers their surface. Excessive amounts of ink must be forced onto them to get enough to the plate’s surface. Proper cleaning goes a long way toward extending printing roller life and increasing your overall quality. Old, hard, dried-out printing rollers make a press very difficult to run.
Improper fountain solution may enter into the picture as a result of roller glaze. A stronger mixture may temporarily enable the press to produce some jobs.
Incorrect roller pressures may simply need adjustment to bring the press back on line. Plate-to-blanket and impression pressures must not be taken for granted, either. If any of these pressures are too light you will automatically run too much ink in an effort to achieve color density. Excessive ink will require excessive water, the combination of which will destroy the driers in sheetfed inks.
If you’re interested in getting things back into shape, give us a call at 303-423-6300. We have the products necessary to do the job.
From Star Bulletin, March, 2000
Q.: We’re having a dampening problem on our 4 color press. We have to run each dampener at a very different speed to prevent washouts or scumming. If we mix the fountain solution strong enough for two of the colors, the other two wash out. What’s the answer?
A.: I suspect you’re feeding all four units from the same fountain solution tank. This method is frowned upon by some of the huge printers around the country. They maintain that each unit may need a different mixture of fountain solution for top performance.
The real key to correctly utilizing a single-tank system is to make sure all four units are in the same condition. Specifically, the metering rollers must all be in the same condition and made of the same material, preferably all made from the same batch of rubber, and made at the same time if possible. Ink rollers should all be as close to the same as well. If worn rollers cause you to have to load any unit with excess ink, you will most likely have a battle on your hands.
Another consideration is the cleanliness of both ink and water rollers. Contaminants from paper will tend to accumulate more readily in the first unit, and it is normally this unit that is prone to the most problems as foreign matter builds up throughout the system and causes toning or other problems that require an increased water feed. Weekly deglazing of all units normally takes care of this problem and permits all units to run close to the same.
Don’t forget printing blanket pressures as well. A unit with light plate-to-blanket pressure will need a heavier ink film to achieve density, which will then need more water to keep the plate clean.
From Star Bulletin, April, 2000
Q.: My press takes forever to wash up, and it keeps getting glazed and contaminated no matter what solvent we use for a washup. What can we do to fix this problem?
A.: A badly worn or misadjusted washup blade will cause a slow washup as will rollers worn smooth from age.
As a washup blade wears, the back side of it rounds off and tightening it only makes matters worse as it bends the tip of it farther away from the oscillating roller it is attempting to scrape clean.
When offset printing press rollers become too old and hard, their “stripe” becomes too narrow and they skid no matter how tight they are adjusted. If the surfaces are worn smooth, a “friction glaze” will be present and they will act like squeegees and actually prevent solvent from being carried to the washup blade or cleanup mat.
If the ink system washes up extremely slow, solvent tends to evaporate and leave residues behind, resulting in a press that seems clean, but quickly contaminates clean colors. You may even experience significant ink roller stripping.
Q.: Why are people telling me not to use gritty deglazers on my rollers?
A.: A young lady running a small 2-color press summed it up better than I could. She said, “My great grandmother used to beat stains out of clothing by smashing it between two rocks. Now we have high tech detergents that do the job much better and easier.”
In addition, a printing press roller manufacturer reminded me that no amount of mechanical grinding will remove chemical contaminants from deep within the pores of the rubber. It will, however, remove some material from hard rollers, and may eventually wear them undersize sufficiently to require their replacement to eliminate certain streaks.
Q.: How can I eliminate the buildup of calcium on my blanket and in my ink and water rollers?
A.: The obvious way would be to buy better paper. Since this is not really an option because such a product is not predictably available at any price, let’s take the realistic approach.
Since any paper contaminants naturally come from the paper, and since the offset printing blanket is the first contact, a top quality blanket is a must. We have several blankets that appear to be winners in this respect. They provide better release to lessen the amount of calcium transfer.
Routine cleaning of printing blankets with solvent and water, followed with RBP Blanket Conditioner perhaps twice a day has been shown to dramatically minimize the transfer of contaminants into your ink and water systems.
Ink rollers should be deglazed weekly then treated at the end of the washup with RBP Cal-Free to dissolve any calcium remaining in the pores of the rubber.
Other than that, remain cognizant of the fact that if every time you run a particular brand of paper you have trouble, try another brand whenever possible.
From Star Bulletin, July, 2000
Q.: Why do some printers use color bars with all sorts of weird color blocks and numbers in addition to the solid squares?
A.: These color bars are used to help monitor press problems and color balance in addition to the solid squares you read with a densitometer. The star targets are very difficult to print perfectly, so mechanical or chemical problems in the press are judged by the pattern of slur toward the center of the target. Some bar sets have a 40% black screen block followed by another block made up of the other three colors, which, if everything is working properly, the two blocks should look the same from a normal viewing distance. Multi-color squares are often included to indicate how well inks are trapping, both in a wet-trap or a dry trapping situation. Other components feature concentric circles or a variety of small dots and squares with numbers next to them. This helps identify problems concerning excessive dot gain.
These bar sets are the number one tool that is used to evaluate printability, and to the trained eye a great many press problems can be quickly identified to enable corrective measures to be taken.
To receive more information or to buy some bar sets contact Graphic Arts Technical Foundation at 412-741-6860, or try their website at http://www.gatf.lm.com. They are located near Pittsburgh, Pennsylvania and have many sets available for various requirements. There are other sets of bars available, but I don’t have any information on any of them.
Always insist on bars from the legitimate manufacturers of these items, don’t let somebody sell you a set out of their trunk, as they may simply be poorly made duplicates and won’t necessarily come with adequate instructions for proper interpretation. How can I say this? Because I already went that route years ago, and the directions were not available so I fought a lot of problems unnecessarily due to my inability to understand what all the components of the color bar were intended to show.
From Star Bulletin, June, 2000
Q.: I was at a large trade show recently and several pressmen running different brands of presses told me not to use Step 1 and 2 Roller Wash. Can you explain?
A.: There are several things at work here. The first is that many new large presses are equipped with automatic roller washing units which only utilize one roller wash product. A good water miscible wash is recommended by all manufacturers I have talked to, so that lets out both Step 1 and 2.
A look back into the history of offset printing as we know it today starts back in the early part of the 1900’s. Letterpress was the predominant printing method, and those presses were all washed up by hand, due to a lack of washup attachments, at least on presses built in this country. To get printing rollers really clean, they just scrubbed them with type wash. Offset presses were initially cleaned the same way, until washup trays were invented. The problem was that typewash quickly damaged the material offset printing rollers were made from back then and not a lot of technology had gone into solvents of any kind, especially for the new, “upstart offset printing method.”
Several chemical companies may have been approached by local printing trade groups, and eventually somebody came up with Step 1, which was a simple mixture of heavy industrial liquid soap (soap cleans hands, right?) and some solvent to help the mixture break down the heavy ink. There was a real terror of getting water near ink rollers back then, so Step 2 was “invented.” Some Step 2 formulas were little more than gas station solvent or paint thinner, but they were utilized to remove the greasy residue left behind by the Step 1. At one point in time there was also a “Step 3,” which may have been something stronger, but I can’t find any information on this.
The problem today is that while Step 1 and 2 will definitely remove ink vehicle and pigment very thoroughly, they can absolutely not remove any water soluble glaze or contamination that builds up in your roller train, not even if you use a thousand gallons of each of them. The symptoms you may encounter are roller stripping of certain ink colors in an extreme case, but the most common occurrence is a lot of ink buildup on blankets, often referred to as “picture framing.” Therefore, for top performance, you would need to deglaze after every washup. The problem is, your rollers won’t last long under these conditions, so another system had to be found.
Water miscible washes were introduced some decades back and they answered the need to clean varnish, pigment and water soluble contaminants all with a single product. Deglazing is normally accomplished in under five minutes once a week.
In my own experience, I used Step 1 and 2 for many years on all sizes of presses, and looking back now, I indeed had a lot of abnormal problems, particularly “picture framing” and poor color control, requiring a lot of makeready sheets to be run through the press to get and hold true color.
Don’t let tradition deter you from trying new products. Call us for some samples of modern printing press roller cleaning products and experience the benefits available to our industry. If you still want a good Step 1 and 2, we can furnish you with two different brands.
From Star Bulletin, January, 2000
Q.: Why do I have constant problems when I mix a metallic ink formula and the color never matches?
A.: We have mixed metallic color formulas at Star for many years now, and the one thing that we have learned after working with four different sheetfed ink manufacturers is that these formulas virtually never match the formula book. This is due, in part, to the multitude of variables that continue to plague the printing industry.
Today we mix only from Superior mixing gold or silver. The printing gold and silver inks print extremely well, but for whatever reason the mixing inks are better suited for consistent color mixing and matching. Once we have corrected the formula and the color matches, that formula is the one we always use on that color. And subsequent mixes always match.
As to the variables, assuming the ink does indeed match our formula book (not necessarily your book or another book), we then arrive at the printing press, where papers impart different looks to sheetfed inks. The condition of the press can change colors dramatically, particularly metallic colors. The type of lighting in the shop will shift colors more than most of us may realize. Because the tiny metallic flakes are flat and totally opaque while printing ink pigment particles are somewhat round and transparent, any mixture of the two will create a color that is very difficult to evaluate. If you don’t think a color matches, simply turn 90 degrees to the light source and you’ll often see a different color; or go near a window where sunlight will further confuse your color perception.
For the ultimate challenge, let’s try to match something that another printer printed last year. He already went through what you’re going through and made a decision at some point and ran the job even though it might not have matched his book either; or maybe his customer approved the color on press after an untold amount of frustration. Now, you’re trying to match the yellowed ink on the furnished sample, and you will most likely have three colors that don’t quite match each other.
I hope this has shed some light on the crux of the problem. Metallic blends have always been problematic and will continue to be so. For best results call your ink supplier for an accurate formula or buy ink already mixed. Then deglaze your press and check all pressure settings, mix new fountain solution and run your job. Good luck!!
From Star Bulletin, January, 2000
Q.: How can I save money on my one pound special ink color mixes?
A.: By mixing them yourself. Labor is more expensive for an ink company because they must mix the ink first then verify that the color is correct. Mixing less than a pound isn’t much of an option, since the raw material is the smallest portion of the cost. Then it has to be neatly canned and labeled and packaged for shipment. And, of course, there’s paperwork that takes additional time.
When most printers need a minimal amount of sheetfed printing ink for a small job, it’s a relatively simple matter to just mix an ounce or two, run the job and discard the leftover ink. You would only mix a pound of ink if you have certain colors that you use often.
You say it’s too time consuming to mix your own printing ink? You don’t have the time? It’s just too complicated?
It shouldn’t be. A simple triple beam or digital scale and a piece of plate glass is the only equipment needed in most cases.
We hire people to mix sheetfed printing ink here at Star, and in as little as fifteen minutes we can teach somebody who has never seen the inside of a printing shop how to use a digital scale and the techniques of thoroughly blending the colors together.
Why a digital scale? Because it always starts at zero regardless of how much ink has been slopped onto it. And digital numbers are much easier for beginners to work with, especially when you need a fraction of a pound. For instance, how much is ¼ of 7/8? Decimals are just easier to understand. And you don’t need to deal with the beam hopping around when you’re attempting to judge how much ink is on the dish.
I had been mixing printing ink for decades when I finally took the time to go to one of our printing ink suppliers for some hands-on training. I thought I knew everything about mixing ink, but I gotta say that I didn’t. I know a lot more now, and I’m still learning, and I have plenty of information to share.
This article could go on and on, but if you are interested in saving a lot of time and money on special mixes, stop by our place and we’ll be happy to give you some pointers and explain the fine points of mixing sheetfed printing ink. I can also furnish a lot of information over the phone, so don’t be afraid to call.
From Star Bulletin, July, 2000
Q.: Our plate supplier says our rollers are severely glazed and we’re having a lot of problems with all brands of plates, especially on the first units of our 4-color press. We have tried all sorts of deglazers without success. What is the next step?
A.: We have seen this problem in a steadily increasing number of shops. It gets back to the fact that there are, indeed, a lot of strange ingredients leaching out of papers and ending up in your printing press ink and water rollers where they build up in layers.
Normal deglazing ordinarily prevents this buildup from occurring, but in the day-to-day rush to turn out jobs we often skip over this very important step and it eventually causes all sorts of problems. The fact that the first units of multi-color presses are the ones affected the worst virtually proves that something is coming out of the paper regardless of what some folks may want you to believe.
I know you don’t want to read this next sentence, but the alternative is to continue having problems and losing valuable production time and materials.
Pull all the rollers out of the press and hand scrub them with our RBP Blanket Conditioner. Don’t even attempt to pour it into the ink roller train in hopes it will accomplish the same results—it most likely won’t. And it will possibly swell some of the press rollers. By hand cleaning, you only have the product on the roller for a very short period of time and the rubbing action of the rag dislodges an unbelievable amount of sludge built up deep in the pores of the rubber. Any slight swelling will go back down usually within fifteen minutes. Any time you reinstall printing press rollers be sure to check and adjust them if necessary.
Printing rollers cleaned this way will normally perform so much better that you’ll see the difference and be more inclined to hand clean them quarterly.
Weekly deglazing will often keep rollers clean enough to avoid emergencies, although many shops deglaze daily during the last washup, which should only add five minutes to the procedure.
Call us for our recommendations for your particular requirements.
Q.: Why are flammable solvents and other chemicals getting to be such a problem to buy?
A.: I’ve been noticing this trend in recent years, and it’s only going to escalate. Manufacturers are yielding to intense scrutiny and pressure from various safety and health agencies plus the escalating cost of fire insurance. The fast drying non-flammables are pretty much already gone due, in part, to their carcinogenic nature and the potential for long term liability to those either manufacturing them or condoning their use.
“Condoning their use” could easily apply to the shop owner who signed the check to pay for such a chemical, even though he or she may or may not realize the purported dangers surrounding the use of the product. For sure, any manufacturer would have deeper pockets so he would also be accused of condoning use of such products, if only through their manufacture.
Delivery of such products is becoming an ever increasing problem. Rumor has it that several transportation companies will soon stop delivering any and all flammables. They already charge so much that it’s nearly prohibitive, especially for small quantities.
Carrying flammables in your own vehicle is not a wise idea unless you are prepared to obtain proper licenses or permits and unlimited insurance.
A lot of research and development dollars have gone into non-flammable solvents for the printing industry, and I must say, there are a lot of products on the market that actually perform better than the old products we all grew up with. We need only adjust our own attitudes slightly to learn of their benefits. No matter how you slice it, things are changing in spite of our likes and dislikes.
If you would like to investigate some of the new products further, give us a call at 303-423-6300 for details.
From Star Bulletin, August, 2000
Q.: The rollers on our press are blistered and there are small splits running around the direction of roller travel. What’s going on?
A.: This is a classic case of “solvent rash.” It is caused by a cleaning solvent that is too harsh for the rubber rollers used in printing presses. You may be using some sort of an industrial cleaner not engineered for the printing industry.
Once this blistering has happened, the only solution is to replace the damaged press rollers and switch to a good wash from a reputable supplier.
Legitimate washes produced for our industry normally contain a number of ingredients specifically added to prevent such problems, as well as to actually extend the life of rollers. One such ingredient is a plasticizing agent added to help prevent drying out the rubber, similar to the substance applied to vinyl tops of cars to protect the material from the effects of the sun.
If you have any further concerns feel free to contact me at 303-423-6300 for some product recommendations.
Q.: You used to make references to a “Press Virus.” What is going on in this area?
A.: It’s still going strong, and presses are becoming contaminated with stray chemicals leached from paper at an alarming rate. Laser printers and copiers are also having problems with toner drum and cartridge contamination, so I don’t think the excuse, “it’s the fountain solution or bad plates,” applies in those cases.
The denial is still going strong, as well. So, rather than try to convince you that there might, in fact, be such a thing as bad paper, I’ll just tell you that once you come to believe such a concept, give me a call for the recommendations to deal with any problems you might encounter.
Q.: We recently bought a used press and nobody seemed to be able to get it to print a saleable job. We had all of our suppliers involved and were still dead in the water after over a month. Now it’s sort of limping along and we are getting a little work off, but the quality is marginal at best. What should I do at this point?
A.: You haven’t told me what make and model of press we’re dealing with, so the first step is to find out whether or not that press model was ever able to print a satisfactory job. By that I mean, there were presses some decades back that didn’t seem capable of printing good work, even at a national trade show. Assuming this is not the case, everything must be brought back to zero.
Remember, that presses at trade shows have been fine tuned to produce the absolute best quality, and typically use only the best supplies available, so if you want to print like they print you must do what they do.
To accomplish this you should first have a good service person go through and tune up the press from front to back to get it in like-new condition, adjusting feeder, side guide and infeed timing, grippers, cylinder and roller pressures. Replace any bad rollers, install a new printing blanket, and test print the machine, using products known to produce good results.
Once you know for sure that the machine is in perfect mechanical condition, then the rest of the variables will have less of an impact on how things turn out. For instance, a bad plate will normally jump right out because streaks can’t be blamed on bad printing press rollers or a bad printing blanket.
When everything mechanical and chemical has been dialed in and you still can’t print a satisfactory job, it may be time to contact the press dealer and see if you can “borrow” a pressman known by the dealer to be able to make that press “sing,” and let him have a crack at it. Maybe he can show your pressman how to do certain things better. I have seen things fixed in just a matter of minutes that had been causing problems for several years.
In my own case, I was at one time the local expert on the Harris 25”, 29” and 36” presses. I helped both service people and other press operators to print better jobs because I was intimately familiar with all the workings of the machines. Even if I couldn’t fix a major problem such as a low spot in a cylinder or a cracked inker frame, I did know what quality the machine was capable of and how to achieve it, assuming that that particular machine was mechanically sound.
As to the part of your question pertaining to what you should do now, start by sending me some press sheets and all other pertinent information, such as make and model of press, offset printing blankets, fountain solution, brand of plate, printing ink, roller wash and approximate age of the printing rollers. If you are in the area where I normally make sales calls, I would be happy to stop in personally and evaluate the situation and make some recommendations. (I no longer do repair service, but I have been known to make small adjustments to a press to solve a problem for a customer, time permitting.)
Q.: Why do we need three different kinds of ink in our shop for our three different presses?
A.: Probably because certain ink companies promote this phenomenon as a way to get your business. The reason a sheetfed printing ink doesn’t perform very well on a particular press is because either the original ink was bad to start with or the press has some mechanical problems that require the use of some special additive to overcome a particular problem.
I remember as a teenager, my buddies and I each had a different opinion about which gasoline ran best in our respective cars. My ’55 Chevy ran best with any major brand of Ethyl. (Texaco Ethyl had some additive in it that produced a strong exhaust smell, which seemingly implied “more horsepower,” so it was very popular with the muscle car set), whereas one of the guys had an old, tired engine in his car and it ran okay with a generic brand that had caused my car to vapor lock. Another fellow always put in a quart of recycled motor oil with a fillup to keep his valves from burning!?!?!? That’s what his dad and uncle always did, so it must be good, right??? Then they ran some “upper cylinder cleaner” through the engine every couple of months to remove all the carbon that built up on the pistons and caused horrible knocking.
See where this is going? My engine was in top condition, so it ran well with a top quality gasoline, whereas those folks with engine problems were always looking for a miracle at the gas pump.
Based on my experience in the pressroom, I believe that if you have your presses tuned up and brought back to average condition you will be able to pick the sheetfed ink that performs the best and just run it—and on all three presses. A properly formulated sheetfed ink is built around proven criteria that should enable it to perform on virtually any press within a size range up to a 40” model.
I know that some of you out there reading this will think I’m totally nuts, but I’ve been in too many pressrooms where they’re running work that would stand the closest quality scrutiny, and the same printing ink is in use on the A. B. Dick, Ryobi and large 6-color press.
Q.: Why do we have trouble printing crisp, clean colors on the back side of C1S [coated one side] cover and cast coated sheets?
A.: I don’t know the chemical reason for this, but it is a fact. For some reason sheetfed ink doesn’t like to print up to full density on the reverse side of most C1S cover papers. On some cartons that the parent sheets come in there is a disclaimer stating something to the effect that you shouldn’t ever print on the back side of the contents of that carton. I guess you are supposed to buy the C2S version for better results.
The next time you’re near a post card rack, take a look at some of the different cards. You’ll most likely see that any printing done on the back is light coverage, and most times it looks like gray ink was used.
In your case, if you must print on the uncoated side, the addition of a little binding varnish will usually permit a heavier ink film to be run and keep more of the ink film on the surface, but be careful of the potential for setoff if running heavy coverage. Also, bear in mind that the front, or coated, side is extremely porous and prone to chalking of the dried ink film, so the addition of Superior Slip-Dri Compound to the ink will dramatically help both chalking and drying. If running both sides, run the uncoated side first and print the other side as soon as it is dry enough to get back through the press, to avoid any problems with picking on the impression cylinder.
Q.: Where do you get the questions you answer in your newsletter, and where do you get your answers? Have you ever been stumped?
A.: The same place I got this one. People I visit ask questions as do those who call me with a particular concern or problem. I try not to get pulled into the middle of a power struggle between shop owner and press person, but it occasionally does happen and I end up being the bad guy in somebody’s eyes.
In some cases the answer is fairly simple, based on decades of pressroom experience. In others I call various chemists or others known to be experts in their fields. I also contact pressmen I know from a former lifetime when I owned a shop, then collate all the information until things begin to make sense and can be explained.
As far as having been stumped, probably the most difficult question had to do with what is the toughest thing a press operator has to contend with on a daily basis. It turned out that it was different for nearly everybody I asked, and I, too, remember a lot of long, frustrating days, so it would probably take a book to answer that question.
Q.: How can I tell if my rollers are bad? Several people have told me they look good and are still soft, but the press is very difficult to get to balance a color evenly.
A.: When printing press rollers are new they have a tacky, velvety feel to them. This tackiness helps sheetfed ink stick to the surface and easily transfer from the ink ductor to the form rollers. As printing press rollers deteriorate with age, the distributor rollers may fail to efficiently carry ink down the train, so excess ink must be run to force it to travel to the form rollers. This results in a very heavy film of ink that overpowers the dampener, necessitating the addition of too much fountain solution to keep the plate clean. Solids fill in and halftones and screens print mushy dots.
In general, the highest quality shops in the nation, the ones that print cosmetic and high end Madison Avenue advertising work replace printing press rollers yearly. They have found that they can usually get more time out of a set of printing rollers, but while they’re doing it, the paper supplier is the one that is really getting wealthy. It’s also a serious reflection on their operation if they have to tell a customer who has come in for a press check that they’ll have to try again next week after they can get in a new set of press rollers to enable them to print the job.
No matter how much or how little you use printing press rollers, the clock ticks at a steady pace and most press rollers will deteriorate more with time than with impressions. Cheap roller washes also contribute immensely to short roller life. A good, brand name roller wash can also be improperly used to the extent that a set of rollers can actually be fried in as little as one day. (It’s a fact, we’ve seen it done on more that one occasion!)
Assuming nothing else is wrong and your printing press rollers are over two years old as you have told me, I could almost guarantee that a new set will solve a multitude of problems. Don’t forget the dampening rollers; they’re even more critical than the ink rollers when it comes to proper dampening.
Q.: Why are there so many different kinds of fountain solution? Is this some kind of gimmick to sell a lot of stuff that doesn’t seem to work very well?
A.: Manufacturers seldom develop new products just to create new products. Normally a new fountain solution might be formulated in response to possibly a geographic request. That is, Colorado is extremely dry when compared to other parts of the country, so a wetter fountain solution might be preferred by some press operators. Then there are shops that only run the simplest work, with old printing press rollers, and they may need a unique fountain solution that will run on several different presses. Different ink/plate/dampener combinations also call for different products. Some types of work only require printing ink to be globbed on the sheet while the background remains clean, so an extremely wet fountain solution would do the job provided ink drying didn’t become a concern. Other, high end, top quality work would call for a product not inclined to attack sheetfed ink and make for flaky solids and grainy screens.
Generally speaking, the fountain solution is what keeps the plate clean, so it should be chosen for its ability to keep the background of the plate clean. On the other hand, the wetting agents such as alcohol or alcohol substitutes are what enable the fountain solution to bridge the dampening rollers and reach the plate.
Different dampening systems require different types of wetting agents, as does the condition of the rollers in the dampener.
When matching up a particular combination in a shop we always take into consideration all of the above criteria, then choose what we think will do the job, based on experience gained in other shops. Then, if we feel a different fountain solution will perform better we’ll make the change. We normally prefer to get a press going using samples rather than sell you a selection of gallons that we can’t take back and that may not work for you.
Q.: I seem to constantly need to readjust my ink fountain to control certain colors. I also get a severe buildup of ink on the ends of the rollers. What’s going on?
A.: An ink fountain’s job is solely to replenish ink that has been consumed. The oscillating rollers in your inker are used to prevent ink from forming ridges that would print as streaks around the cylinder. Oscillators also have the nasty habit of forcing sheetfed ink to the ends of the rollers, where it collects and eventually causes problems.
Early presses such as Multi, Chief and A. B. Dick were only intended to print what we use copy machines for today. There was absolutely no intention to enable the running of solids or screens, so the first ink fountains on the presses had only a few notches, providing for perhaps less than a half inch of ink fountain roller travel. This proved adequate until some of us decided to print that job of fifty copies of an 8½ x 11 solid. The fountain couldn’t keep up, so skip feeding was often utilized on such a short run.
In the early sixties Multi came out with an improved press with a long stroke ink fountain ratchet capable of around a half revolution of the roller. This helped immensely. Other manufacturers quickly followed with the A. B. Dick Pro eventually coming out with today’s 11 notch fountain.
With these modern ratchet systems we learned that we could control even light coverage jobs much better by running a lot of notches and turning in the fountain keys to provide a thinner film of ink over a longer area. By turning in the end keys where no ink was being consumed on a light form, the fountain roller actually pulls excess ink off the ductor and returns it to the fountain, so it doesn’t accumulate on the printing press roller ends where it can cause the ink rollers to actually lift apart in some cases and fail to touch properly in the center.
I remember back in the early sixties watching pressmen scrape ink off the oscillator roller with an ink knife. This went on all day long, and was done to remove the piled ink from the ends of the rollers. A lot of oscillators were damaged when the ink knife got caught, and some pressmen were damaged when the oscillator flew out of the press at them.
One old pressman I worked with showed me how to properly operate the ink fountain by using a lot of rotation, and I haven’t had any problems since. He pointed out how, by running on one or two notches, you were letting the press try to control its own color, which was never quite right, while doing it correctly put the pressman in charge of the press.
To prove this concept to yourself, do this simple test: Load a bunch of ink onto the printing press rollers and let the press idle. Make sure there’s so much ink that the rollers barely turn. Then flip the ratchet control to maximum and let the press continue to idle with the ductor operating and the ink fountain keys turned in. Within five minutes most of the ink will have traveled back to the ink fountain and the rollers will have a thin film of ink ready to print a job.
This is called “running a long fountain,” and will produce much better color control in most cases. It will also take a bit of practice to master, but once you do master it you’ll never go back to running a “short fountain.”
Q.: We run a lot of single color work on our two color press. Will it harm the rollers in the first unit to run without ink?
A.: Yes, it will harm the printing press rollers if run long enough without the lubrication of the sheetfed ink film. Normally, a short run of under a few thousand sheets is okay, and many printers simply leave the previous ink on throughout the run before washing up both units. Over the long haul, though, we recommend the use of Dri-Rol-Lube to both protect the printing press rollers and actually clean them while you’re running another job. Be sure to switch units occasionally so both units can receive the benefit of this deep cleaning.
Use of oil is never recommended, since many rubber compounds will swell and turn to jelly with certain oils. The only way to determine if you have an incompatible mix is when it’s too late.
Printing press rollers will build up excessive heat if allowed to run dry, and a friction glaze can develop, which cannot be removed with deglazers. In an extreme case, if running fast for even an hour or two, heat may build up to the extent that press rollers may melt or begin smoking.
Q.: We’ve been told that we need a good deglazer. How can we determine which one is best?
(This is a very controversial subject, so, please don’t anybody get mad at me if my answer contradicts your opinion. My answer is based on years of experience in hundreds of shops and responses from many customers.)
A.: In general there are two types of deglazers; passive and aggressive. In addition to this there are two methods of deglazing; mechanical and chemical.
Mechanical deglazing is usually done by removing the rollers from the press and scrubbing them with a rag and plenty of pumice powder. This is time consuming and not very consistent. A gritty paste can be applied to the rollers and the press can be idled for fifteen minutes or so to allow the abrasive to grind the surface of the rollers and break down hard friction glaze. This is normally done to squeeze a few more jobs out of an old press, since the grinding that occurs to the rollers’ surface can eventually destroy the hard rollers. It is the least effective deglazing process, and the grit is very hard to get out of the rollers. It may take several washups before all the grit is removed and plate damage no longer occurs.
Chemical deglazing is the preferred method, since removing stray chemicals from the roller pores is the normal objective with any deglazing or decontaminating process. Mechanical deglazers cannot dig deep into the pores of the rubber to remove embedded chemicals, regardless of how much you use.
Passive chemical deglazers are normally furnished as a thick paste, and work by surrounding small particles of calcium or pigment when left to idle on the rollers for fifteen minutes or so. The captured particles are then removed during the completion of the washup cycle.
Aggressive chemical deglazers actually swell the pores of the rubber printing press rollers very slightly while the contaminants buried deep within these pores are dissolved and lifted out. These contaminants would include dried sheetfed ink vehicle, pigment particles, gum, calcium, lint and paper dust, to mention a few. Deglazing with an aggressive deglazer is normally achieved in under five minutes, since these products work very fast and overuse can contribute to printing press roller swell. Severely glazed press rollers may need to be removed from the press so they can be hand scrubbed with a liquid deglazer.
We recommend Tower® Restorkleen as an extremely good, aggressive, liquid deglazer. Ink Magnet is another good product, somewhat weaker, and is very good at deep cleaning printing rollers for quick color changes. By using a top quality wash such as Tower® Shortstop or Colorkleen, deglazing is normally only necessary once a week or so.
For a really good system to clean your rollers, we recommend our Press Diet© Cleaning System. We have put together a startup kit of selected products to thoroughly clean your press rollers of glaze, pigment and contamination, and includes printed instructions for use. Please call us for our current price, due to fluctuations in the price of most products containing petroleum ingredients. The kit provides you with 5 gallons of wash, plus deglazers and saves you approximately $30.00 over the separate prices.
From Star Bulletin, March, 1999
Q.: We have been told not to use a water miscible wash because it can leave a residue. What should we use instead?
A.: Water miscible blanket & roller washes were designed to be used with the addition of from 10% to 50% water. We see far more problems caused by not using a water miscible blanket & roller wash, or using it incorrectly, than we see from any buildup of the surfactants which are incorporated into the wash to make it go into emulsion with water.
If you stop and think about it, solvent cannot remove dried water solubles no matter how much you use. (Think about a messy high chair tray that is easily cleaned with warm water). On the other hand, try cleaning a spilled greasy mess with water. It doesn’t work either. Now, if you could mix the solvent with water, you could easily clean both messes with the same product.
With all the stray ingredients found in today’s papers, your printing press rollers and offset printing blankets might easily resemble that high chair tray if examined with a microscope. Printing ink won’t stick to a water soluble contamination once the fountain solution works its way through the ink film and dampens the layer of sludge. This forces you to run excessive ink, which then requires more fountain solution to keep the plate clean. The printing press rollers then begin skidding and picture framing and toning appear. Large presses may not tone, but picture framing and drying problems will begin to be a problem, in addition to severe streaks in screens and solids.
It’s true that a non-water miscible solvent blanket & roller wash may seem to work better for a while, but you are only surface cleaning your rollers and the contaminants dry on the printing press rollers in layers, which will eventually result in a press that you may not even be able to run line copy on. In some cases press rollers become so contaminated that they must be replaced if even strong deglazers won’t do the job.
According to the hundreds of printers who are using it, Star’s Press Diet© cleaning system remains the most efficient combination around. If you feel like you’re struggling, call us at 303-423-6300 for more information.
From Star Bulletin, January, 1999
Q.: How important are cylinder pressures and what is the easiest and most reliable way to check them? Our newest press doesn’t have cylinder bearers so how would we go about using a packing gauge if we were to buy one?
A.: Experts tell us that printing press blanket pressures, while one of the most important tolerances to be maintained in an offset press, is also the most overlooked area of many presses.
Conventional offset printing blankets are packed to a .002”-.003” squeeze. Their construction is very hard so consequently any slight jam up or wrinkled sheet can smash an area and render the blanket useless. Attempting to maintain pressures this close on a press with any wear at all is a near impossibility.
Compressible printing press blankets were designed to absorb variations in the press bearings and stand up to most smashes, therefore, printing press blanket manufacturers recommended adding an additional .004” over the squeeze used for a conventional blanket. Therefore, the recommended squeeze is .006”-.007” between plate and blanket. This dimension has proved correct for decades. Less pressure transfers less sheetfed ink, so more must be run to cover the paper, resulting in blotchy screens and filled-in solids, not to mention increased setoff and ruined jobs.
On presses without bearers, your manual should specify a total of plate and packing as well as a total of blanket and packing. This may either assume a conventional or a compressible printing press blanket, which may not necessarily be specified, so you’re working in the dark in most cases. You also don’t positively know that the gap between cylinders while on impression is absolutely correct. It may not have been properly set by whoever last worked on it. A packing gauge will only indicate how high you are packed above the surface of each cylinder, not that the cylinders are properly calibrated.
Bear in mind that plates, printing press blankets and packing sheets are seldom the exact thickness stated, so you must always measure everything with a micrometer.
To simplify final verification of plate-to-blanket do a stripe test. This may prove difficult on some late model presses, but it really is an accurate test. Just ink your plate up solid and (somehow) put the plate on impression to the printing blanket. The transferred stripe should be approximately 3/8” wide if you have a squeeze of .006”. Each 1/16” of pressure would equal .001” of squeeze. This is affected slightly by cylinder diameter, but is true of cylinders from around 7” up to 10”, larger cylinders will show a somewhat larger stripe.
Also remember that the impression cylinder must be adjusted for best printability. The numbers, while presumably correct, do not take into consideration the finish of different papers. While a high gloss sheet may print perfect with a setting of .006”, the same thickness smooth offset may need a setting of .001” and a linen or vellum sheet may need to be squeezed down to -.002” to force ink into the pattern or grain of the sheet.
From Star Bulletin, January, 1999
Q.: Why are we continually fighting a build-up of ink on our blankets? It is very bad in the non-image areas and eventually shows up on the sheet as tone bars or an overall tint. We have tried several kinds of fountain solution and numerous brands of ink with no luck.
A.: Contrary to popular belief, it’s seldom the sheetfed ink or fountain solution! Different products may generate slightly different results, more by accident (luck) than by design. This ink buildup is commonly referred to as “picture framing.”
This phenomenon is caused by contaminated or glazed printing press rollers. Judging by the number of new customers we have acquired recently, the problem is getting worse and our Press Diet© Roller Cleaning System has been recently modified to accommodate the newest contaminants leaching out of the paper.
Our Press Diet© Roller Cleaning System is in use in literally hundreds of shops in a ten-state area, and our customers, both new and old tell us that our system really works. Word-of-mouth remains one of our strongest salesmen, and people tell us that our prices are very competitive.
Q.: Why does your “Press Diet” roller cleaning system seem so complicated? Why can’t we just use step 1 and 2 and be done with it?
A.: Many printers asked us for a cleaning system that would clean everything out of their printing press rollers without causing any excessive roller swell. They also wanted a system that wouldn’t require a chemistry degree to use.
Step one and two systems have been around for a very long time. The concept is to remove pigment and varnish with a heavy detergent and solvent mixture, then rinse it off with a simple solvent rinse. The system does this very well. The problem is that today’s papers are so full of recycled stray ingredients that this system simply cannot remove this buildup from the pores of your printing press rollers, no matter how much of it you use.
It’s this buildup that causes all sorts of printability problems, such as excessive drying times, picture framing, or buildup on the printing blanket, toning or tinting, stripping of sheetfed ink from the press rollers, poor color control resulting in density drift, etc.
Therefore, you need a potent deglazer to retain any semblance of cleanliness. Using such a product too often will quickly swell your printing press rollers. The alternative is several weaker deglazers that take a long time to use and may even leave stubborn contaminants behind.
Over the past five or six years we have fine tuned our Press Diet© Roller Maintenance System and can offer a truly efficient, predictable cleaning system which is in use in literally hundreds of printing shops in the ten state region we serve.
A value priced start-up kit is available from Star, and includes full instructions for cleaning printing press rollers thoroughly and quickly every time. And, with Star, you can be assured that we’ll continuously update it if new products become available and prove their superiority.
Q.: Why do we have drying problems with certain papers, and what can we do to prevent this?
A.: Over the decades, certain papers have stood out as continually causing drying problems due to either the chemical makeup of their coatings or the surface finish.
Old timers will all tell you that index and tag were the two most famous non-drying papers, even in the letterpress days. Plate finish card stock was another one; it was pounded between calendering rolls to produce a polished finish. Smooth offset is still done this way in many cases. Linen finished stock was embossed and seemed to take extra ink to look nice, so drying was, and still is, a problem, due also to the incredible abundance of surface dust caused by the process of dry embossing the finish into the brittle coating of the paper. C1S covers are a real pain! One brand today tells you not to even think about printing on the back side. If you try, you’ll need about ten pounds of printing ink on the rollers to even print a washed-out line of type. And it’ll most likely offset (setoff) and take a long time to dry.
To prevent this, you can make a list of sheets that have proven to be problematic in your shop and put it where it will be easiest for press people to see it and add extra drier to your sheetfed ink. We also have an additive, W-1600 that, when added to sheetfed ink will stimulate drying. Liquid cobalt can be added to the fountain solution as well, and is easy to use. We carry it in quarts from RBP Chemical Corp. as Drying Stimulator. Normal dosage is from ½ to 1 ounce per gallon of finished fountain solution.
Since normal cobalt drier may consist of 3% cobalt and 97% non-drying oil, addition of too much may, in fact, dramatically retard drying. We have available a 12% cobalt drier, but it needs to be used very carefully to prevent sheetfed ink from drying on the printing press rollers while running. It could be problematic without proper supervision, so we keep it hidden on the back shelf.
Remember, also, that contaminated or glazed press rollers will for sure cause severe drying problems, so proper roller cleaning is always the first line of defense and cheap insurance.