Uneven ink coverage on RZ970E

[zeugma]

Hi,
I'm having a little trouble getting even ink coverage on my Riso RZ970E (see image attached). The checkered test print shows noticeably lighter coverage along two parallel lines down the length of the page. Does someone here have an idea what this might be related to and how to fix it (I cleaned the screen assembly and drum completely today before this test print was done)?
Any help would be much appreciated!
Thanks.
Mark

IMG_7149.JPG

[Paco Telescopios]

Hello,

What I can say is very obvious, but this happens in my machines (RP3700) when I have bad ink flux, normally due to a cogged ink filter.
Did you disassemble the whole drum, or only cleaned from the outside?
If not the filter, this could be related to the ink pump or the ink distributor I suppose

But I'm really new to Riso world, so better if you wait to other opinions

Paco

[itchyfinger@att.net]

its been a while since I worked on both A B Dick and Rizo digital dups. Make sure your impression roller is clean. any buil;d up or groves can cause this as well as the ink knife being plugged in those areas. You may have to pull the ink cylinder totally apart and clean it and or replace the ink knife. good luck and wear some gloves

[zeugma]

Thanks to both of you for the tips! Will be trying them over the next few days