Print issue with Risograph GR3770

[Guest]

I've just bought a second hand Risograph GR3770 and have a problem with printing. The copies are fine from about 1 inch from the leading edge on, but the top of the print doesn't appear. The centre is blank down to 1 inch from the top. Moving out from the centre, it's blank for progressively less in both directions. Do any of you know what could be causing this?

There's also a problem with the horizontal alignment. The dial next to the paper feed doesn't work and the images print about 10mm to the right of where they should be. How do I fix this?

Many thanks in advance for any help offered.

[RRodgers]

Re: Print issue with Risograph GR3770

How does it look off the glass? Be sure there is not a piece of paper under the master.

[aschamberlain]

Re: Print issue with Risograph GR3770

Looking at the master on the drum, it's got the text from the paper original printed on to it, but there is little to no ink over the area that isn't printing properly.

[aschamberlain]

Re: Print issue with Risograph GR3770

I've tried it with the red drum and the image is still misaligned but apart from that it's printing fine.

[aschamberlain]

Re: Print issue with Risograph GR3770

I've taken out the black drum to have a look at it. The pattern where the ink isn't coming through is the same at both the leading and trailing edge of the drum (it doesn't affect what's actually printed at the trailing edge). Would it be sensible for me to dismantle this and see if there is any build up of congealed ink around this position that's stopping fresh stuff from coming through? Could there be a different cause of this issue?

Also, any help with the alignment problem would be hugely appreciated - I'm at a loss as to what to do with this.

[ddude]

Re: Print issue with Risograph GR3770

Before taking the drum apart, I would try cleaning the drum screen with solvent as discussed here: http://www.copytechnet.com/forums/di...-all-over.html

Do not scrub the screen, just remove the master from the drum and lay a solvent soaked rag on the problem area and let the ink dissolve. Citrus solvent works well, but you can try other types of wash, like platen cleaner or blanket wash, whatever you have access to.

[RRodgers]

Re: Print issue with Risograph GR3770

Before taking the drum apart, I would try cleaning the drum screen with solvent as discussed here: http://www.copytechnet.com/forums/di...-all-over.html

Do not scrub the screen, just remove the master from the drum and lay a solvent soaked rag on the problem area and let the ink dissolve. Citrus solvent works well, but you can try other types of wash, like platen cleaner or blanket wash, whatever you have access to.

Yeah, I would do that first. Taking the drum apart isn't really needed to clean it and can be a pain.