Odd Inking Problem

I’m printing envelopes on my windmill and am having a terrible inking problem that I can’t figure out. I was curious if anybody has any ideas to remedy this:

On every forth impression, the ink turns out like the attached picture. The next 3 prints look great, then back to this again.

I’ve turned the press over very slowly to see each step as it’s printing and nothing seems odd to me. This 4th impression seems to have the same ink pattern also - it’s missing ink on the plate in the same area every time.

Any ideas?

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Hello, have you tried to readjust the ink rollers?
I’ve experienced similar problems and everything went fine when I lowered the rollers a bit.
Another cause cold be old worn out rollers which become to hard or to soft after a couple of years.

You might need to adjust the tracks your rollers ride on. Look on the side and there are four nuts with number. Loosen the nuts and move the rollers closer or away from the form (look for the dial printed on the machine +/-)

On the top of the ink drum is a lever that holds the rollers up, are you sure it’s not in the up position…and it is keeping the rollers from inking?

also the tracks the rollers ride on must be kept clean, any oil or dirt on them and you won’t get good prints.

All the above , if no luck swap the upper and lower inkers on the forme over and turn one round right to left ,test if no different turn the other round and test , if the problem is unchanged check the vibrating roller (the one that transfers the ink from the duct to the ink train) look at it in good light as it operates and if there is a shiny patch that appears to flash in the light turn that roller over and test ,if the shiny patch moves to the other side of the machine the roller needs adjustment or replacement .
Do the same with every roller until you get a result that shows you have moved the one that is a problem ,once you have found it you can sometimes put a rough roller elsewhere in the train and the oscillating will make the problem less evident .
It is possible you could be picking up oil from the crap that collects beneath the big spread roller that is directly in front of you .
if you still have a problem check that your miraclon or nylo is aclually flat on the base and not got a bubble in it that is stopping the inker from contacting the whole surface evenly .If you dont mind getting mucky bang the form with the heel of your hand and if it knocks you need to lock it up again so it is perfectly flat ,a springy form and nylos dont go well .

Thanks for the tips guys! Here are some things to note:

- My rollers are new and it great condition
- My rails are in a good position as I just checked them with a roller gauge.
- Rails seem to be clean and dry
- The rollers are striking the ink drum
- I tried wiping the form rollers clean and then allowing them to reink on the ink drum, but that didn’t work. I’m thinking about washing the whole press down and trying again.

Again, the odd thing about this is that every fourth print is the one that looks bad. The three before that one looks great every time. I started to actually skip feed when that forth one came around and was able to get a good impression on all prints. Not something I want to do every time though :(

Another thing that’s odd. I tried recreating the problem with normal stock (I’m printing envelopes). The normal stock didn’t have this inking problem. So, it seems like it’s something unique with the envelopes. This is making my head hurt!

@peter - Thanks for all the tips. I’ll go through these and see what I can find.

Are you using PP plates? Oil or rubber based ink?

lower your rollers a bit

lower your rollers a bit

@Girl with a kluge - I’m using PP with rubber based ink.

First guess would be solvent contamination of the form. What are you using to clean your plates?

Gerald
http://BielerPress.blogspot.com

Try oil based ink and see if that makes a difference.

Evan -

This happens on my table top once and a while and only with some plates some of the time. No idea why. If your rollers are getting ink but the plate isn’t in some spots… you can simply slip a piece of paper behind the chase once it’s locked up. That brings the chase just a smidge forward. Sometimes I slip 2 pieces of copy paper behind and it does the trick. Easy fix and it’s not permanent. Glad to see you’re doing great things!

Tracy

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photo.JPG

This may sound weird, but I remember having trouble getting a plate to accept ink, and someone recommended to me to wipe the clean plate with a dryer sheet to reduce the static that seemed to be building up on the plate, preventing the ink from adhering.

Paul

How about the make ready ? It can be a problem with envelopes as the flaps and seams move. Not every envelope is quite the same.

Evan,
Problems that repeat in some sequence every 2, 4, 5, 8 -whatever are typically associated with something that rotates and comes around over the number of rotations.
This could be a gear tooth that is broken, a roller or truck that is eccentric and has a high or low spot that comes up every so many counts.
I would hand crank the press through the four impression cycles and look very carefully as the rollers pass over the form. My guess is that you will find one roller with a high spot or that does not rotate fully over the form. If it is sticking and not rotating it would actually work as a squeegee as it passes over the form. In this case you would find a build up of ink on the roller that did not transfer. You may also find that the next sheet (env.) through has a heavier or even an impression with an outline in the area that didn’t print on the problem piece.
Use the scientific method, change one thing at a time until you find a solution. You may try rearranging your rollers and or trucks. You might try flipping the roller left to right.
I’d bet something in your ink train is not perfectly round. Good luck,
Steve

Evan,
After re-reading your post I must also comment on the fact that you said it worked fine on non envelope stock.
Although the folding of envelopes can vary by small fractions of an inch it would not be enough to change the overall pressure (thickness) in the area where the side seams and flap overlap.
However if these are simple white wove envelopes, I’d guess 24# white wove, than you could actually have a situation where one roll of 20# was mounted on the folding machine as they were manufactured 4 up. In that case the difference in the two weights would be multiplied by three times in the area where the face, seam and fold overlap.This would dramatically alter your pressure (thickness) in this overlap area. Hold the envelope up to a light and see if the “non-printing” are matches the overlap area.
Conceptually this is also a rotational issue, in that the envelopes would have been manufactured with 4 rolls, 1 being different and coming up on every forth envelope.
If this is the case, discard every forth one and let your envelope supplier know.

re Steve Varvaro’s suggestion about the inking problem: This is an extremely good example of how valuable Briar Press for solving strange problems. If it turns out to be the cause, Steve deserves special mention.

I have come across some strange causes of difficulties, but I must admit that only this year did I “tumble” to a possible cause of a bad feed on an automatic press which I saw in 1965; it has taken me all that time to realise that it may have been a humidity problem, the paper may have had different moisture content through the stack; the paper had been transported from a geographic area of high humidity to a place where the air was much drier; but behaviour of paper on a press is not my department, so it’s only a guess. Years later I visited a shop which letterpress printed labels for canned food, and found that registration was a severe problem; they had moved from a place of relatively stable humidity to near a large river, and gusty wind may have changed humidity in a short time (not air-conditioned).

Also the one where someone went through all of the steps to check a photosetter (took most of the day) to come to the last: Check the supply of paper! Someone had not reset the counter (which showed how much paper was left) when putting in a new roll, so there was no paper although the indicator showed otherwise. We had another photosetter which (literally, it actually did it) blew a fuse because someone put a space code on the end of a headline which was also quadded flush left; this one was more in line with my work. [It was New Year’s Eve, about midnight.]

Alan.