Various GR3750 Issues

DanielM · 04-02-2013

Hello,

I recently got a GR 3750 and I'm having a few issues with it.

The biggest issue is that my color drums don't print as well as my black drum. The black prints well and solid, but the color drums are pretty light and patchy. I've tried cleaning the drum screens with Armor All Cleaner & Degreaser, which helped some. I got the drums from someone who hadn't used them in a while and which had been in an unheated / uncooled garage in Indiana. I attached images of two gray scale tests made from the same laser printed original.

The second issue I'm having is a white stripe in the images, spaced about 60 mm apart, which I notice is about 1/2 the circumference of the impression roller (or whatever you call the roller that puts the paper in contact with the drum).

The third issue is that I have trouble feeding regular 20 lb. copy paper. It inevitably feeds up to 5 sheets at once. Using heavier paper, like 100# text weight, it feeds fine.

Any suggestions would be most appreciated!

Thanks!

Daniel

RISO Black.jpg RISO Red.jpg

**gillje** · 04-02-2013

Hey Daniel,

Besides cleaning, try replacing the ink cartridges with new/fresh tubes... If the drums have been sitting for a while, it could be that the ink itself is no longer good. I think the shelf life of riso ink is something like 2 yrs?

Is that white stripe parallel to the pressure roller? Take the drum out and check to see if there are any marks or damage on the roller... It could just need to be cleaned.

There are 2 green dials where the paper feeds. When you're looking at it, the dial on the left controls the pressure between the stripper pad and the feed tire and the dial on the right controls the angle of the stripper pad. These can be easily adjusted to accommodate different types of paper. I usually keep mine at 3 o'clock (left dial) and 11 o'clock (right dial). It'll be a bit of trial and error... if that doesn't help, it could be that the feed tire and stripper pad are either worn or dirty.

good luck!