inking problems
I’ve been printing a lot on a C & P 8x12 this year, and have a recurrent inking problem. Small areas suddenly get light or disappear. Not slurring, just very little ink on the typefaces. After eliminating many possible reasons…trucks, impression, shape of rollers, height of rollers, ink disk rotation and surface, location of form on platen….I’ve come down to the rubber. The rollers were on the press when purchased out of a storage barn, but I could see some of the familiar blue color beneath the ink-staining & that made me think they were relatively recent. Also, they are very regular cylinders, with no marring…but the surfaces are very glossy. I’ve tried pomade and another conditioning ointment, but the problem persists. Here’s my question: am I describing ‘glazing” ? My other rubber rollers have a slightly tacky feel, as of course do the composition rollers. If rubber surfaces get smooth like that, does ink not transfer as well? Would it cause such random problems, even after printing beautifully for fifty copies? And, if that is indeed the problem, then is there any way to recondition them, or should I just get new rollers?
thanks for any insights…
I got a couple blue-colored rollers with my first press and it turned out they were vinyl, not rubber. They were relatively hard and glossy besides being dirty with ink and were obviously beyond their useful life. I’ve subsequently read in several places that vinyl rollers do not last as long as rubber and exibit the issues mentioned as they get older. My guess is that you may have vinyl rollers that are past their prime.
Rich
Front Room Press
Milford, NJ
http://frontroompress.com
http://frontroompress.blogspot.com
Intermittant light inking usually indicates either low spots on the rollers or high spots on the trucks (common on expansion triucks that have been over-expanded to compensate for low tracks). The problem becomes evident when the bad spots on all three rollers line up. Shifting the rollers will solve the problem temporarily, until they line up again.
Exactly how did you eliminate trucks and roller shape as possible causes? These can be subtle things, especiallyif one is trying to set the rollers for photpolymer use.
Are the rollers taking ink over the whole surface? If it is just glazing, use of Putz Pomade (abrasive roller treatment) or Roller Rejuvenator (agressive solvent treatment) per instructions may reduce glaze.
That comment about vinyl rollers seems on the mark. I’ve really scrubbed these rollers with Putz pomade and another product loaned me by a local printer. The end result is always the same ultra-smooth glossy finish, unlike my rubber rollers.
As to trucks, I have Morgans, but I got new gaskets from NA graphics, and made two wood shims to keep the trucks from touching the rail when the press is not being used so they wouldn’t compress. As to shape: I set them on a flat surface and rolled them slowly- suspended a sliver above so I could see the gap(got that tip here in a post). They were all very symmetrical. The other detail is that I’ve been printing from metal type, and I’ve let the rollers be a little closer to the form than perfect, allowing a 3/16” stripe on the gauge…to be sure there’s no doubt about contact. I suppose that might cause some rub-off of ink…? But wouldn’t it then show itself over wider areas?
I’m leaning towards new rollers. I love the Tarheel composition ones I got two years ago for another press, and live in Northern California with less drastic weather changes. They have a great tacky feel and ink transfer is wonderful.
Thanks for the thoughtful advice…