RISO GR3770 - Faded print/old ink

[Cp31]

hello everyone,

im working that had been sitting for a (very) long time, 3 to 6 years, im not sure exactly. i got it running again – thanks to this forum for the valuable information !

im having trouble getting a nice ink coverage.

i cleaned the drum screen with mineral spirits, and the copies were pretty good right after this. however i came back the next day, and running the machine again the ink coverage had decreased (by a lot). i ran the "idling" operation, ran around 100 copies on a confidential master, no noticeable improvement.

my ink is probably very very old (way more than shelf life). so that just might be it. also, i read that the printer should be sitting in a 15° (celsius) room minimum. this is not the case at the moment, and it has not for a few years. this might had to the problem...
(little question about this specifically : is this "fixable" by increasing heating around the machine for a few minutes before printing, or is it a constant requirement ?)

however : its systematically the top third of the page that is faded – the rest of the page is not perfect, but prints a very readable text.
this leads me to think that maybe there is a pressure problem ? or maybe one part of the drum is more caked than the other ?
id be happy with the ink output as it is if it was even all over...

i am gonna try getting new cartridges. do you know what other cartridges than the original GR ones are compatible ?

my other question would be do you think a pressure adjustment (or more cleaning) would help get the ink coverage even on all of the printing area ?

thanks

[jermyth]

I'd say without looking at samples that the drum needs more cleaning. I suspect the drum shell has A LOT of dried ink in it. You may have to disassemble the drum to clean out the inside of the shell. The GR is a dinosaur. I know a lot of people keep running them, but parts a rare. I don't know about supplies. I don't think I have manuals for them anymore but you can try searching, you will need one to take the drum apart.
Good Luck.

[Cp31]

thanks for the answer !!

yeah i figured it is a dinosaur... but got it for free with around 500k copies, so felt it was worth a bit of time, and it actually works...

i do have the manuals – was a bit scared (still am) to have to take the drum apart, especially since i have just this one and would not want to mess it up, they are so hard to find in europe... and never done this before.

since i noticed improvement with mineral spirits i think i will try it again, letting the screen soak a bit more...
i read here that u could "stick a bit of diesel or kerosene in the end of an ink tube and stick in the machine. should disolve the hardened ink inside the drum". how would you go about doing this ? like actually put a small amount of solvant IN the cartridge ?

will give updates ! thanks again

[slimslob]

After sitting that long the ink in it has most likely thickened considerably. You can either disassemble the drum and remove all that thickened ink or just put a fresh ink cartridge in and start running prints with a high coverage percentage. That will eventually thin and flush out the old ink.