New from Russia

First thing that comes to mind, is too much ink. You only need a small amount for letterpress.

Thank you very much for your reply.
I think so too.
But I am set rolls so that they barely touch the polymer (minimal contact)

Polymer is a magic blend of perfect roller height (sounds like you’re close there) and very precise metering of ink. If you have the paper, start running impression with the rollers clean (fountain loaded) then start the fountain and see how the ink density builds on the sheet. If you’re getting plugging and smear before the ink density rises to provide good fill, then you may have a packing problem.

600 gsm stock, cylinder presses, and heavy impression do not play well together. Slur is a major problem with this combination. The slur occurs because the sheet (likely due to impression) is “dragging” on the plate as it is trying to pull the inked sheet off the type/plate. Others can explain this better and should be along shortly.

Good afternoon.
Thank you very much for your reply.
You helped me.
A few questions:
1) What does that mean - fountain and fountain load?

Thank you so much!!!!

Guys!
Give more tips and ideas;-)
Need your help!
Thank you!

If you are running a fountain (not sure if a Korrex is a proof press or a cylinder (ala Heidelberg—which has an ink reservoir/fountain). If yours is a proof press, then disregard mention of the fountain, as you won’t have/use it. If you do have a fountain, loading only means having ink in it (and having the fountain “keys” set to put ink on your impression roller(s) where you want it.

The idea is to start with a clean press and build up ink to the desired level and see what happens, rather than putting on a quantity of ink and realizing it’s too much. Alternately, if you think there’s too much ink, you can sheet off the excess and try again. Sheeting can be done by threading a clean sheet through the ink rollers and pulling the ink covered sheet out—being careful to wind wind up with the sheet wrapped around a roller and being unable to remove it easily.

Kasilov -

From a quick google search, I see that your Korex may be similar to our Vandercooks - a flatbed cylinder proof press.

There are a number of factors that affect image quality. You need to consider them all:

1) Amount of ink.
2) Roller pressure
3) Roller condition
4) Ink condition
5) Impression

This print appears to be the result of either too much ink or too much roller pressure. But it could also be too much ink and too *little* pressure. Too little roller pressure could trick you into adding more ink when what you need is a bit more roller pressure.

Mike’s right. Photopolymer plates need a very precise amount of ink roller pressure to transfer ink well. Achieving that balance can be a challenge.

In any case, there is too much ink on this print. It appears that ink is getting into and filling the “open” area of the design.

Since you state that you have set your ink rollers to minimal pressure, I would suggest that you start again with just a little bit of ink - not even enough to cover the solid area. If you can get a crisp print of the Eiffel Tower with less ink, you just had too much ink on the press.

If the print improves, your pressure is okay. If it does not, you need to do some testing of the ink roller pressure.

A quick way to adjust roller pressure - for testing only - is to add sheets of paper beneath your base. This will raise your base and increase roller pressure. This is not good practice in general, but it is is good as a quick and simple test. If the image improves with more paper behind the base, then you will want to lower their height to increase roller pressure

I would also check the condition of the rollers.

The ink rollers should be soft enough to hold the image of your form as they roll over it. If you do not see an image on the roller, you may want to increase the pressure a bit or get softer rollers.

Check each roller, by the way - and at both ends. You may have the rollers at different heights. Leveling rollers on a proof press is not always easy. Looking at the latent image on the rollers can help you see if each of the rollers are making contact with the same pressure. If one roller shows an image and the other does not, you will want to lower the one that does not show an image. You can remove the upper steel rollers to get a better look as you roll over the form.

It may also help to do this testing using a wider form - one that will let you check both ends of both rollers.

Also - on this job, you are attempting a ‘reverse’ where the background is inked and the text is “open”. This sort of a design is always a challenge on letterpress. Easier on a flatbed cylinder, but a challenge nonetheless.

Van Son Ink is generally pretty good out of the can. Some inks can seperate oil and pigment. Quickson is an oil-based offset ink. It’s not likely the problem, but do make sure that thes ink works well on other jobs - and is fresh.

- Alan

glad you got the rollers as in earlier post you were asking about specifications, you have not mentioned a guide that printers use to test typehigh.roller height, a type high little cylinder on a rod stick to put under rollers and on top of the bed to check rollers are evenly inking and the width of the strip of ink on the little cylinder tells you how much pressure there is from the form roller, check out Gerald Bielers website for his recommendations(buy his book polymer printing on flatbed presses excellent) as to the width of this strip for polymer., this might help a little too. Have you joined the FAG community, Vanderblog, various groups on Flickr too as suggested>this will give you more contacts with cylinder flatbed presses.

Thank you so much for your reply! You are a miracle! You really helped me advice!
I love this forum!
Happy New Year!

Jonathan, Sergei has got a roller gauge. I did see it on some of the photos that he sent me at the end of last year. i have explained him how to use it. But from the photos that he posted recently, I see he’s making good progress. Keep going Sergei…

ah, super, Thomas-yes every encouragement to him, the Korrex will be european type high so hope his gauge is also for this type height. I wonder where he is Russia………….

It seems from looking at his photos that he’s got Russian height, 25.1 mm! A Korrex Berlin-model motorized press, with a bed size of 50 x 65 cm.

That’s right :-)
25.1
And i am near Moscow :-)