Masters not printing straight - Wonky?

[crumbcabin]

Hello!

I print using a RP3105ep.

I have YELLOW TEAL ORANGE PINK BLACK BLUE RED GREEN drums.
Initially I thought the issue was related to each drum but have realised it is more likely something mechanical within the machine.

The problem is that the bottom of each master prints slightly wonky. The top is usually straight but as the master image moves down the paper I can see it veers to the left slightly, sometimes by 1mm with other 2mm or occasionally even 3mm.
A lot of the prints I do involve duotone and printing booklets, which becomes problematic when the bottom half of the page is always mis registered but the top half looks good. I know registration is never perfect that's the beauty of Riso. However, it's proving impossible to improve registration techniques when each master is wonky and not printing straight !!

Has anyone had similar issues and been able to fix this issue?

I have checked alignment holes at front of pressure roller and they are aligned.

The machine has only printed around a million masters on the clock.

Any help would be great, thank you so much for your time !!

[Iowatech]

Re: Masters not printing straight - Wonky?

Pictures, please?

[20gaugeO/U]

Re: Masters not printing straight - Wonky?

Do you get any wrinkling with the master on any of the drums? Take the pressure roller out of the machine and roll it on a good flat table, see any daylight under it?

That or there is to much tension on one end of the master roll as it's being loaded on the drum. I don't remember what RP used as a braking system while loading the master but it has evolved over the models/years. Open the master roll cover and put extra tension on one end as it's burning the master and loading it.

I'd stick with one drum and see if you can better or worsen the issue not use all drums to troubleshoot. Use 11x17 paper and print Test Mode 50 (or any 50-55) and see what you get from an internal print.

I assume you are printing from a PC and not copying from the glass???

[crumbcabin]

Re: Masters not printing straight - Wonky?

Thank you both for reply. Will get some photos tomorrow !

The masters only wrinkle once in a while but not often enough to be a serious issue.

Will try out test mode 50 tomorrow and let you know what's happening.

Yep, from a PC not from glass.

Thank you!