C&P not inking correctly
Hello -
I print on a 10x15 C&P that was refurbished and I believe that the rollers are not very old (I’m not exactly sure when they were replaced). I set all my rollers using a type gauge on all 4 corners of the press bed. When I put my chase in the press, it doesn’t ink the entire plate when it’s set correctly according to the gauge. I am printing with photopolymer and using a standard boxcar base.
Could the rollers be bad? Any help would be greatly appreciated.
Do you have photos of the rollers, trucks, rails, etc? It could be a problem with any of these, but there could also be some buckling in your lockup depending on how tight you’ve got your quoins.
Brad.
You just have to be a little smarter than the press. Investigate, isolate and remedy. You look at and only change one thing at a time and test again.
Unless you have one of those fine old chases with handles, remove the chase, clean the plate, and put the chase back in upside down. Make sure your plate is very dry with no solvent residue on it. Roll the press and ink the form. Have the inked portion and the uninked portion changed sides? Make a precision measuring tool from a 1” wide piece of 20 # copy paper. Place the paper strip over the inked portion of the plate and hand roll the rollers up over the strip. Tug the strip out. Repeat the test over the uninked portion of the plate. What have you learned?
Try turning your rollers end for end. Only one roller at a time. Did it make any difference? Do you know anything more now?
You say you’re using a standard Boxcar base, I believe the deep relief base is recommended for C&P platten presses
Three Quoins,
I don’t think that was the issue he was reporting- it wasn’t, “Help my base is inking” it was, “Help my inking is inconsistent across the bed of my press”
If the pattern is repeated in a cyclical way, then it could be something to do with your rollers- especially if you very carefully set your rails and determined that they were soundly set and are straight/don’t have blemishes.
As has already been said, remove one variable at a time until you discover your issue. You might try taking your rollers off one by one to see if any of them are out of true.
It’s already been said that your lockup might be distorted, but since you’re locking a base up I would assume that this would mean one part would ‘tilt’ and the other ‘drop’ in reference to the bed of the press, if anything. Try loosening the lockup and planing it and slowly tightening it just enough to keep the base in place.
Regarding the rollers and their trueness- you can put them, one at a time, on a pretty flat surface such as a thick sheet of glass or an imposing/composing stone and roll it along slowly, checking to see if it’s level. If your rubber is warped or the cores are out of true (more likely the surface is warped than the cores, I would think, but one never knows if they were poorly shipped or handled previous to your posession)
Once you determine that the rails are level and unblemished, and that your TRUCKS are true and unblemished, I would personally think it’d have to be one of these other variables.