GR3750 - printed image travels up and down page

[ianmck]

The image printed on paper travels up and down the paper rather than appearing in the same place. The travel can be as much as 20mm. The first sheet is the worst and then it settles down into smaller distances of travel but still as much as 14mm. I have 4 drums and the issue is the same no matter which drum I use.

Can anyone advise what travel can reasonable be expected in a normally working machine, and if the travel is outside this what I would need to do to correct it.

Thanks.

[RRodgers]

Sounds like the brake is slipping on the guild roller. You can pull it out and using some scotch bright to roughen it back up again.

[joelsa12]

specs from Riso are + or - 1 mm at speed 3 if you are having issues like this i would check for worn parts( feed tires, stripper sheet, load spring) check adjustments( timing gap, paper tray height) make sure that your timing roller is clean also.

[20gaugeO/U]

All what Joelsa said, especially the load spring. If those parts are all great then the main drive belt might be stretched.

[ianmck]

Found the solution

I had a look at ther guide roller - tried to remove it but then chickened when I realised I could access it from the inside!

Then I noticed on the manual page next to the removal instructions a note about the position of the P disk being wrong causing unstable print position. Sure enough the P disk was aligned incorrectly and once adjusted to the correct psoition the reigstration is stable again with 1mm variation over test run of 20 prints.


Thanks for everyone's advice.