Thank you in advance to anyone having any advice on my printing problem I’m having on my Vandercook 4 and SP-15.
I’m finding that when I’m trying to print (using metal type, wood type), the ink is getting slurred over the form causing a dragging in the ink, or ghosting on the bottom side of the image, so the side that the rollers hit first. I get pretty close to correcting this problem through playing with roller height
adjustment, but then I start to get ghosting! Sigh.
So I’ve spend hours and hours….and hours, make ready galore trying to find the spot where the rollers are happy so I don’t run into this problem in such an unfixable way everytime I try and print. No luck.
I was wondering if it could be ink tackiness, the packing seems at a good spot too although I’m not sure what the correct amount is supposed to be as the standard, or could there be some other thing I’m not thinking of?
If anyone can help, I would very much appreciate it.
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Can you send a photo of the problem. Have you rotated the form either 90 or 180 degrees? Does the problem follow the form or the rollers when you do this?
After re-reading you description it sounds like the rollers are bumping up over the edge of the type when they first make contact with the form.
Have you rotated the form either 90 or 180 degrees? Does the problem follow the form or, the rollers when you do this?
Do you have room to lock up two type high bars or rules running parallel to the direction of roller travel on either side of the form, but placed so the rollers hit the bars first. The roller(s) can than begin rolling on the bars so that when they encounter the type they are already type high, and in motion. This can correct a slur.
The ghosting in letterpress is usually mechanical in nature and may have a lot to do with what the form looks like. If the metal type comes first it will strip some of the ink off of the roller(s) and leave a lack of ink available in those areas when it hits the wood. Conversely if it hits the wood first it can strip most of the ink away, leaving little ink to cover the metal type.
These are just a few ideas.
Again, a picture would be most helpful.
Check your roller height and also be sure the roller drive gears are engaging properly (is the press made for galley height or standard .918 — if the latter and you’re setup in a galley your type is too high by .050 inch). Usually this kind of problem is caused by one roller being out of sync with the other due to driving issues, or one is spinning slightly before the return. You should have an oscillating idler roller as well, which should help with coverage issues.
Make sure your ink is stiff enough. It should not crawl down the ink knife when held vertically. Simple enough. Also, don’t use transparent inks for general usage.
Use very little ink at start up and adjust your impression first, add ink until it balances. Too much impression and that might not happen.
Can’t think of much more to add since you say you are having the same problem on two presses.
Without seeing the set-up, I’d have to agree with Bob that the problem sounds to be that the ink rollers are either set too low, or that they don’t start turning until they hit the form, and some of the ink is wiping off on the edges of the image until the rollers get up to speed.
Roller drive gears that are loose or not present would seem to be the most likely cause. Maybe the rollers have been put in the presses with the drive gears on the wrong side of the press where they don’t engage with the proper gear rack.