Ghosting “double inking” of print

This problem is usually caused by the rollers slightly skidding, or slipping in the trucks if they aren’t keyed to the cores. The image is removing the ink from the rollers but when they return after the first, downward, pass they are slightly rotated and the fresh edge of the image area on the roller lays down that extra edge of ink on the image. I’m going to guess the plate was locked up rotated 90 degrees counterclockwise from your photo and the rollers hit the bear’s back first on the upward return trip to the ink disc. With a large solid like that your best bet is probably either rider rollers for extra ink or double-rolling between impressions — skip-feeding.

Bob

Thanks for the quick response.

Why are the rollers skidding?

Are rider rollers also named roller bearers?

Sometimes if you’re running the press very fast the abrupt stop at the bottom of the rollers’ travel will cause them to skid a small amount, but it’s enough to cause the effect you’re seeing. Also, if the trucks can turn even slightly on the cores that will cause it too. Rider rollers are additional rollers that sit on top of the form rollers and add ink-carrying capacity. (see below)

Bob

rollers with rider.jpg

In the uk we refer to any of the areas either side of the forme bed on which either rollers run on or a cylinder rolls along as a bearer it bears the object that rolls on it , i have learned US call them runners , i never heard them called other than a bearer but such peculiarities exist all over the print world it seems .

Ohh interesting. I use a treadle and go pretty slow but I often stop it to check registration. Not abruptly though.

Well, the trucks are not perfectly keyed to the cores because the person (who I won’t name) who recasted my rollers, added rubber too close to the “keys/locking” area so the trucks can’t get close enough to ‘key in’.

I guess I could cut the ends of the rubber?

Do you think it’s worth just getting brand new rollers and trucks? Start fresh? Or will that not make much of a difference?

Thanks again!

And where would find a rider roller to purchase?

You can trim the rubber at the ends to allow the trucks to seat correctly. I have had to do this on Vandercook SP-15 rollers before in order to get the clearance I need to mount the gear to the core. If you use a fresh utility knife blade and take care you can make a pretty clean job of it.

Daniel Morris
The Arm Letterpress
Brooklyn, NY

Not so happy camper, just trim a little off the ends of the rollers so you can get the trucks all the way on, if the rollers aren’t keyed you will always have problems, you could also try bearers on each side of the chase, this sometimes helps make the rollers turn. isn’t printing fun!!!!, good luck Dick G.

I ran into this problem once on my Vandercook, and it drove me crazy. At that time the remedy was setting the rollers to just touch the top of the plate in the lightest setting possible. This is difficult to do on a C&P, but can be accomplished with tape. It cannot possibly be a skidding problem, because the image is doubled. What is happening is the image is stripping so much ink from the roller that the recharge is not adding enough when it picks up again, and the natural shift of the roller leaves extra ink at the foot of the bear (that is a bear isn’t it?). The easiest remedy is going to be what Ad Lib recommended, and if you can occasionally manually spin the ink disk to help distribute the ink better I think you will be able to solve your problem. Reducing your impression would also keep the plate from hitting the rollers so hard, which is probably contributing to your problem. I’ve never seen an 8” x 12” with a rider roller, and it would be really difficult to adapt the standard set-up to do that.

Paul

On a C&P, mechanical ghosting when printing solids is hard to overcome without rider rollers, which are hard to find. The rollers just do not hit the form at the exact same rotation of the roller. Perhaps rosin will reduce slippage.
In the US, the parts of the press supporting are called tracks, or more recently, rails. Bearer is a rather ambiguous term. In the US it can refer to the bed bearers or cylinder bearers of a cylinder press, or added material in the form to support rollers or equalize impression.

Well, It seems to be getting worse. It never used to be like this and even smaller images — size of a pea — are now getting the same effect. So I’m not sure if it’s a problem where it’s taking too much ink.

I’m pretty much at the point where I can’t print anything anymore unless it’s thin lines.

Do you think this is a time then to get new rollers/trucks? If getting a rider roller isn’t possible.

I just don’t know why it’s doing this now… it never really did this before and now it’s doing it for even small images.

is your shop heated???? ink don’t like the cold, also the rollers hate cold also.

On a C&P the problem is that the ink for the image is removed from the roller on the downstroke, but the roller shifts while reversing direction below the form, and the slight difference brings an overlap between the inked and un-inked parts of the roller which shows up on the form. Without a rider there can’t be a recharge until the rollers get to the ink disk, but double-rolling can jjust amplify the problem. There is no way of making rollers hit a form in exactly the same position every time.
It is possible to make a rider yourself, Mo over on LetPress had pictures posted at another site which I can’t quite remenber. Two Piglets?

Are you certain that all three rollers are set correctly?

Dan

Thanks for everyone’s help so far. I really appreciate it.

So I keyed in the trucks and added washers on the ends so there’s no room between the saddles and the trucks.

Still have the ghosting problem.

Parallel - How do the rollers shift below the form? They move down and come back up and shouldn’t shift while reversing direction at the bottom?
I’m also not sure I have the “know-how” to make my own rider. I saw that photo of Two Piglets…

dickg - It is…I’ve had this problem when it was still warm outside. what is the optimal temperature though?

Dan - I hope so! :) I am attaching photos of my set up for you.

Thanks!

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P1020671.JPG

i keep my shop at about 55 or 60 degrees, then during the day i run a small coal stove to bring the heat up to about 65 to 70 degrees, i leave the heat on all the time cause it takes a long time to warm everything up in the morning. If you have rubber rollers you could try cleaning them with an offset glaze remover, after many washups your rollers will get shinny and the ink don’t run well on them, i deglaze my rollers every couple of months, i use my presses daily. You could try turning your roller hooks on the bottom roller, don’t know if it will help but i run mine the other way.

Great — the temperature in my studio is around 68 so it’s good.

So I keyed in the trucks but there is still a little wiggle room back and forth (vertically) — is that normal? Or should it be tight?
If it needs to be tight, how do you get it like that?

Thanks again everyone!

The rollers shift because nothing is perfect: friction, surface contaminants, varying lubrication, the rapid change in direction, all play a role. Get a Thompson Autoplaten and the roller trucks and tracks are actually geared, but even then the slightest wear to the teeth and you’d get ghosting there as well.
Looking back on my time with C&Ps, nothing improved their product more than a rider roller.

Well, I’d be willing to pay someone if they can make a rider roller for me since it’s something that I have no knowledge or how-to and they’re not made commercially.

Thanks!

The rollers shift because that is the way presses were designed to operate. If the rollers hit in the same place each time it would be very hard to ink the forms.

Paul