Riso GR3750 Master slips down:

[ybnews]

My Riso GR 3750 print image slips down from the gripper as much as 1/4" within 1000 copies. This is especially annoying when trying to print a 2 color job.
I have to hit the Print Position button twice to the right of center about every 200 sheets just to keep image relativly centered. Is my master slipping? How can I fix this?
Thanks,
Dana Lewis
Henry's Copy Center

[20gaugeO/U]

Your problem is with the pressure roller under the drum. Put a new pressure roller in. Do the adjustments on the attached tech bulletin. You should be good as long as your pressure is set fine.

[cobiray]

The machine could just need a good cleaning also. Clean the feed tires, stripper, timing and guide rollers and press roller.

[joelsa12]

Adjusting the pressure roller is a B*tch!

My least favorite adjustment on the Riso by all standards. I would do this at last resort. If you have another print drum put that in and see if the problem still exists. If it does I would check the pressure roller. The bearings go out on this and will cause that problem. Does it do it on all types of paper? It it is only on longer paper you have an issue with the 2nd paper feed not releasing the paper and an adjustment needs to be made. If it does not still do it after changing the drum then it is a drum issue. The clamp could have lost its magnetism and it is not holding on to the master. Or the 0-180 magnet could be sticking up. As the machine works this magnet is sticking up and causing the clamp to open a little with each revolution of the drum. Thus causing the mast to slip. Good luck and I hope that you do not have to adjust the pressure cradle, but if you do good luck.

[Kopyrtek]

Most problems with this is the pressure roller not being centered with the drum.Remove the pressure cradle and center it within the cradle.
Think it takes a 19mm to remove the nut holding the assy in.