Riso Rp3105 & Rp3790 paper sticks to drum

[jeh]

Hello,

I have a Riso RP3105ep since a couple of years and recently acquired an RP3790, using the color drums I already had for the first one on both the machines now.


The problem that I recently started having is that paper sticks to the drums, in both machines and with different drums. I'm printing images that are quite dark, but I never had any problems with things like that before. Lighter paper is obvciously more problematic than heavier stock. I'm printing a3 images on paper that's 320x435mm. I have the feeling that the separator somehow doesn't function how it should, even though it seems in the right position when I checked according to the service manual. Sometimes it even leaves a mark in the middle of the paper, because it's touching it. There's also a lot of ink on the drums in general I have the feeling, even when I print with the least contrast (and at its slowest).


Could it have to do with the fact that I reset both machines recently to its factory settings? Don't really remember why I did that. Maybe techs do standard adjustments to these types of Riso to prevent certain standard problems from happening? I also read something about adjusting the timing, but can't really figure it out with the service manual.


What could I do to solve this problem or what else should/can I check?


Thanks a lot for any help!

Jan

[jeh]

Re: Riso Rp3105 & Rp3790 paper sticks to drum

Another thing I just noticed is that the paper doesn't come out smooth or steady, it's extremely shaky (from left to right). When it doesn't come out like this, it mostly folds back somehow and turns back around the drum.

I made a master on the RP3105, had that problem, then put the drum in the 3790, exactly the same. Might have something to do with the drum then?

[RRodgers]

Re: Riso Rp3105 & Rp3790 paper sticks to drum

Check the blower in the pick off finger (I think that model has one) check to be sure the suction fan is turning for the exit area as well.

[Iowatech]

Re: Riso Rp3105 & Rp3790 paper sticks to drum

Make sure the lead edge of what you are printing doesn't have an unusually heavy amount of ink on it. That is the cause of at least 99% of all drum wraps on Risos.

[20gaugeO/U]

Re: Riso Rp3105 & Rp3790 paper sticks to drum

I agree with Iowa. To much lead edge black. But when the o-ring in the sep pump for the orange finger goes out it get less tolerant to lead edge black.