Inconsistent fading on plates. Please help!
After one year of printing with no real problems, all of a sudden I can’t seem to get through print runs without having fading and thick areas in my prints. I’m using a C&P 8x12 with boxcar deep relief plates. What’s happening all of a sudden is that while printing an invitation which is mainly text on a 4x5 area out of the blue the plate will not ink up on a certain line of text but will be really thick on another area, so I adjust it with adding tape to the rails or taking it away which helps for the next pass, but all of a sudden it’s fading in a different area and is really thick in another area. I can’t seem to get through 50 prints without having the majority of them being either too faint or too thick in one area or another. I’ve ask for advice from many. I even switched from composition rollers to rubber rollers. Didn’t work. I switched from metal trucks to expansion trucks. Didn’t work. I’ve switched my ink. Didn’t work. Any ideas will greatly be appreciated! I’ve attached a photo of the problem I’m getting. It’s a crappy print, nothing is consistent.
take a look at chuck williams’ “my C&P betrayed me” I’ve written some thoughts about that. Not sure if my answer is correct, but you may want to check it out for ideas.
tom
Thank you, well, since I’ve taken every other approach to trying to solve this problem, my final step will be to switch the photopolymer plates to the magnesium plates offered at Owosso Graphic Arts. And they offer one free plate to new customers, so I get to try it basically for free. I’ll post whether that solves the entire problem or not after I try them out. The only thing that bums me out about switching over to magnesium plates other than it being slightly more expensive is the registration was so much easier with photopolymer than it looks to be with metal plates. Is there a quick and cost effective way to register a 2-color job with the metal plates. I only know of getting two separate plates each with the exact same base size. But that seems to waste a lot of surface area if I only have an inch or so of the second color.
Sorry for the difficulties you are having, fine printing can be very frustrating sometimes.
I am not trying to rub salt in the wound but will shoot out a few comments for what they are worth.
Things to check:
1. If you are making the form ready, under the tympan sheet, perhaps the top, draw sheet is not tight (baggy due to humidity or other) and is letting the packing sheets move. Top sheet should be tight and under packing sheets cut to the proper size so they can’t move.
2. Fixing the problem, by process of elimination, and going directly to the problem is hard to do, when one is in a rush schedule to deliver a job. So as not to have the problem “snowball”. We have all seen a small snowball rolled down a hill and it just gets bigger.
3. If the ink is good (not drying on press, does not have a drop or two of oil in the ink train and the ink knife clean and the can of ink skinned well before using. Also if the batch of ink you are using is not burned (having been run through the mill too fast when made). Or if it is old ink gotten from a shop that was going to throw it out (it is an unknown).
4. If the pressman wipes some ink off a roller or disc or plate with a rag that has solvent on it and doesn’t wait for it to dry or dissipate before resuming the run it can have that effect you describe. Or if the pressman has sweaty hands and touches the plate, it can cause a similiar effect.
5. If the roller cores are true, the bearers clean, the roller trucks clean so the rollers are not slipping. If the plate is good, and the base is good and type high.
6. If the under packing is new and not been used for previous runs.
7. If the caliper of the paper being run is consistent. If the paper is clean and if the paper is siezed on both sides evenly. Is there spray powder on the paper from a previous run?
8. Is there press solvent under the patent base or oil (squirting out to a different place upon each new impression?
9. Are your hands clean when you touch the sheets, or have the sheets been contaminated somehow? Was the cutter clean where they were cut? Glicerin and silicone travel a long way undetected.
Just some thoughts to help jog your memory of the sequences leading up to the problem.
How about some basic makeready? Build up a bit at the light areas to get a better impression. Cut away beneath the heavy areas to lighten the impression.
Rich P.
Front Room Press
Milford, NJ
Rpolinski, it sounds like her makeready is decent and fairly consistent, given that the faded are is in a different place on every print…
I have never printed with the boxcar plates, so I don’t know if the have a tendency to ripple or shift on the base.
As Calvine pointed out there are all kinds of possibilities here, the worst of which, not mentioned, is approach. Fast, easy, cheap. The most efficient way to print is to invest in quality materials and supplies and equipment, and education. That is the fastest, easiest, and most economical way as there is far less time spend dealing with problems, wasted material, and ruined jobs and, I would think, an absolute necessity if one is dealing with paying clients.
But given the traveling ink problem I would think this has to do either with the press itself or the rollers. The main thing to consider, since the press was working fine up until, is what was changed in the operation that might now contribute to this problem.
Gerald
Thank you all for your comments. I am definitely excited to educate myself and am willing to put in the time and effort that it’s going to take because I truly love when I see a wonderful finished product. I still haven’t figured it out quite yet, but here’s where I am so far. I ordered a magnesium plate to try it out, but after really studying the situation last night I definitely think it has to do with my roller, trucks and rails, as some have suggested. Possibly all working together improperly. I have to say, since I’ve owned my press (being the beginner I am) have never gotten the absolute perfect print. My prints have been acceptable, but I truly want to perfect the final product eventually. From the beginning, I’ve never been able to build up my rails evenly and have the impression look even. I’ve always had to build up my rail here and there to accommodate thick areas and light areas in the print, and that changed most every time I tried printing a new job from a new plate. But at least it was consistent throughout the job and I could get it done. But now I’m noticing that there is a cycle of fading and/or thickening horizontally down the print within the same plate and same run. Eventually I’ll get a couple good ones, but then the fading/thickening will appear again after a couple more passes. If I stop my press once I see the fading and turn each of my trucks, it seems to fix it for a couple more passes. I’ve measured each of my trucks with a caliper and they all seem to be the same size around. I did switch out my trucks to the Morgan expansion trucks and the problem still occurred, which makes me think I can rule that out. I have not measured along the length of my rollers to see if the diameter is the same on each roller, but I’ve switched from my composition rollers to brand new rubber rollers and had the same problem with either one. If it were the rails that were causing the problem, I would think that the fading/thickening would at least be consistently in the same place and not shift down the print throughout the run. I’ve considered that my rollers might be slipping. With my eye, I cannot tell. I’ve cleaned my rails and trucks thoroughly though.
Hope someone might still have some thoughts. thanks again.
Amy
I agree with Gerald that the press is giving you problems, not the plates.
“I definitely think it has to do with my roller, trucks and rails, as some have suggested. Possibly all working together improperly.”
Me too. You mention that you have switched rollers from composition to rubber but I’d check them anyway for roundness—put them on an absolutely flat surface and roll them back and forth while shining a flashlight behind them. If you see light occasionally, that’s your problem.
Is it common to get new rollers that are inconsistent? If so, how does anyone purchase new rollers without constantly having to exchange them?
Brand new rollers shouldn’t be a problem (I’d check them anyway) but I have had problems with getting rollers re-covered and finding them out of round. I recently sent back a set of 3 rollers and had them redone because of this problem.
When you used the bad rollers, did you get the same issue of the plate not getting inked on some areas and really heavy in others, and then having it shift elsewhere on the plate?
I checked the rollers out of the box and found the problem so I shipped them back and did not use them but “low spots” or uneven, out of round rollers can cause this problem (as well as other factors previously mentioned in various posts on this issue.)
Try some roller bearers outside the paper area. That should eliminate any roller slurring due to uneven and worn rails. My bearers are type-high right angle aluminum or steel with the ends bent down to allow the rollers to smoothly run up onto the bearers. But any type-high fairly wide rule should work in a pinch. Be careful to make sure all type and gage pins are out of the way of the bearers. You can also cut away the tympan and packing where the bearers ht the platen to avoid getting a lot of ink on the platen.
How many rollers you use for inking on this press?
If you use all three rollers, try to take out the third one, i.e. the bottom one
with its own arms. Sometimes inking with two rollers will do the trick.
I sometimes use only one roller to print certains job. Or the rollers are really bad.
Good luck.
Thanks for your suggestion. To get through the job I did end up taking off one roller, but it was the top roller and it helped me control the situation a bit better, but didn’t entirely fix the problem. I will switch and try taking off the bottom one. I did check all my rollers and they are in perfect condition. All appear to be even when I roll them over a smooth surface. I couldn’t shine any light between them and the table. I’ll let you know how taking off the bottom roller goes. thanks.
Amy
I have found that most problems with print quality are roller related. Rollers should be replaced regularly and maintained correctly. After washup they should be wiped with a rollerwash/water mixture to remove water soluable contaminates. They should also be deglazed with a roller paste (Putz Pomade) regularly.
I have been using the Boxcar base and their plates for about three years. As I have an imagesetter, I make my oun plates. Yes, I scrub them out by hand. The problems I have had have been trying to print too fine an image. The plates simply cannot support a hairline or some delicate cursive fonts with my processing technique.
The only other issue to bring up is housekeeping. A drop of oil on a roller or ink disk can cause real problems after the press is inked up. The rollers should feel velvety smooth and slightly tacky. If they feel slimy they should cleaned with roller wash before they are inked up.
Sumner
I will definitely get some of the Putz Pomade and deglaze my rollers. This is only the 5th time using the new rubber rollers, but I had the same problem with my composition rollers as well (all of a sudden after one year). I did a test with a plate that had a solid block of color so I could really examine the ink coverage on the plate and noticed that the ink is not covering the entire print block all the time. Sometimes there is a horizontal band that is faded across the plate and eventually it moves down or up the plate. It remains that way for a couple passes until I stop the press and physically turn the rollers to a different position and then start the press up again and the ink will cover up that fade. Within the same test I noticed that the plate started getting too much ink in one area of the plate, so much pressure that it even started inking the back of the plate, again in a horizontal band. I removed the top roller and it stopped inking the back plate. But even with the top roller removed I still would get the fading band across at certain times.
PROBLEM FIXED! The problem was simply my rollers were larger than my trucks. Even though I used my composition rollers for a year with no problem, they expanded in the humidity to be larger than my trucks. So when I got the new rubber rollers, I never adjusted my Morgan expansion trucks to the same size as the new rollers. So it seems to be a rookie mistake but throughout the troubleshooting I’ve learned absolutely tons about my press and other problems that might have occurred and how to solve them. Thanks to all, especially Alan in Frenchtown who suggest it might be the size of my trucks!