Ghosting & uneven inking

We are struggling with roller/truck ratio and the resulting ghosting. We used vinolith rollers for years and a switch to rubber over the past couple of years has been rough. We use 3 rollers on a 10x15 c&p but no riding roller. The rollers don’t seem to last long despite conditioning and good cleaning. One of my pressman has complained of wrist pain because he’s trying to skip print more to solve the issue but that’s not a long term solution.

I searched a bit in the forum and wanted to condense the ideas into one topic:
Looking for feedback on
Where everyone likes to recover their roller cores.
Do adjustable trucks exist anymore? I can’t find them.
Does anyone like a rider roller or recommend it?
Any other tips on ghosting?

Thanks all! Been printing for 13 years, but roller changes are throwing me for a loop so I guess I’ve had it easy til now!

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Haven’t purchased new rollers in years. Mine are rubber from NA Graphics and work fine. I’ve heard good things about Advance and Ramco, but not used them.
Most come supplied with cores and it doesn’t seem to be advantageous to have existing cores recovered for smaller C&P presses, like the 10x15. The only maker of composition rollers, Tarheel, is no longer doing so.

The only adjustable trucks I’ve seen are used or old new stock. Delrin trucks are the way to go, I think.

Rider rollers are no longer made as far as I know and very thin on the ground in used equipment. I’ve not seen one for either the 8x12 or 10x15. Ever. Some folks have built their own. It would be cool to find one for my 8x12 OS.

Roller bearers (90 degree angled, type high metal that overhangs the chase have made a lot of my inking problems go away, especially slurring caused by low, inconsistently flat, rails and worn trucks. Much cheaper than grinding and restoring the rails to spec. Not as messy as taping rails and/or trucks.

You don’t say what you’re printing from (metal type, metal plates, photopolymer, etc.) This can affect inking to a great extent.

Double inking and double impression are both fairly standard techniques I use when necessary to achieve the desired results.

If your job involves a large solid area larger than the circumference of the rollers you can expect to see ghosting.
The solutions are fitting a rider roller, double inking or possibly turning the job through 90 degrees if one side is narrower than the other.

If your image is smaller then rollers, not as noted by platenprinter above, then, I was searching this topic the other day because I was having an issue. I was printing a large text only form on a C&P 10x15 Craftsman and there was a lot of over inking just along the bottom half inch of the image. I tried adjusting the packing and the impression control but no luck there. Then I read a response from Mick from way back which got me on track….

“Mick on Monotype, Could your “ghost Images” be in actual fact repeat marks from slipping rollers. Thompson,s incorporated chain assisted rollers to stop slip but still had to incorporate riders for more inking power. Oiling, probably only the same amount and frequency as you would to the saddles and spindles of your form rollers, maybe the tiniest dab of copperslip grease, or your equivelant under the little carrier hooks, it will hang in longer than machine oil, especially when you hit 5,000 I.P.H. for 7 hours on the trot??? P.M.A.Good luck.”

So using a solvent I cleaned the rails and trucks of oil. I wiped down the saddles and the roller core between the trucks and roller to prevent oil from migrating onto trucks and rails. That improved things alot but still wasn’t perfect so I also placed some masking tape on the rails, just on the bottom curve where the trucks reverse direction. This added enough grab to prevent the trucks from slipping and solved the inking problem. It also reduced ghosting to almost nothing. I can still see a tiny line of a ghost on some jobs but I don’t think a client would notice.

The roller passes down over the form inking the plate but when it reaches the bottom the trucks slip a little bit and the roller takes a split second to start rolling in the reverse direction after it starts moving up. When the roller contacts the plate again it is no longer aligned with the image the same way it was on the downward journey and lays down fresh ink in a slightly different spot on the form and that causes the ghost image.

Thank you Mick!

Bruce

Do roller trucks and rails have to be smooth surfaced…especially the modern plastic ones on smooth metal rails….if slightly roughened would they not grip a fraction together to avoid skipping slipping…..treadle press Jardine I have has a leather strip that rollers run on….as did quite a few older presses….tight springs will pull on rollers when not perpendicular…..as rollers move on a radius at either end of their travel the spring tension is pulling them back that might make them skid……and strong tension is required to counteract this to provide grip but actually exacerbates the possibility of skid?

Rider rollers are the answer to the problem usually. Heidelberg offer a suggestion of cleaning the rails and applying rosin to stop skidding. I have also heard say that securing the trucks to the roller ends by means of a grub screw, which Heidelberg have done by putting
Slots in their trucks to marry up with the roller cores.