Risograph GR3770 Master not sticking to drum et al

[NONPOROUS]

Hi,

I recently bought a used blue drum for my GR and purchased new ink. The master inked up and printed fine when I first inserted the new ink, but now a few days later it seems as if the ink won't pass through the screen, not even allowing the master to stick to the drum. One odd thing I noticed was that ink seemed to 'bleed' over the margins of the master and onto the drum a few days ago, you can kind of see the residual mess in the pics. I tried wiping it down with WD40 to no avail. All my other drums work fine and the inside straw seems to be just as gooey as the other ones. Any idea what the problem / solution could be? Thanks!

Pics:

http://i.imgur.com/JabuyjT.jpg

http://i.imgur.com/G9rIA5d.jpg

http://i.imgur.com/WUbWzuP.jpg

[Iowatech]

Re: Risograph GR3770 Master not sticking to drum et al

Sorry, can't actually see your machine, so I have to ask -
How many prints are you making per master? If you are making less than 20 prints per master, this will continue to be a problem.

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

Thanks for the reply. I realize that it takes a handful of prints to ink up. The photo result is after running 100+ sheets thru the machine with that master.

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

Update: After running several hundred sheets thru the master gets more inked up as it should but only on the center as a 'stripe' on the master, the rest of the master is completely uninked.

Pic: http://i.imgur.com/GnyctVV.jpg

[Iowatech]

Re: Risograph GR3770 Master not sticking to drum et al

OK, try this:
Put the drum in the machine, and then take the ink bottle out of the drum. Look down through the ink bottle cavity and you should see some rollers. There is a large roller dead center on the bottom of the drum, a silver roller above and to the left of that one, and there will be an ink bead that should look a little like a .5"-.75" roller where they meet.
Also, if you can be really careful, press the drum home button while looking at the rollers.
Let us know what you see there.

[gillje]

Re: Risograph GR3770 Master not sticking to drum et al

If the drum was properly inked up when you got it, and inked up when you put the new ink in for the first time but then started to dry up after that, it could be an issue with the ink you put in it. Riso ink has a shelf life of 2 years, and tubes should be date stamped. Any tubes that aren't date stamped are expired. Another way to tell if ink is expired is if it has become separated and an oily liquid comes out of the nozzle.

[antone]

Re: Risograph GR3770 Master not sticking to drum et al

Pull off screens clean holes with alclohal ok

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

@Iowatech

Thanks. The small middle roller isn't spinning, but the big one at the bottom is. That roller on my other working drums spins so this must be the issue then huh. Any steps I should take to fix this?? Thanks!

[antone]

Re: Risograph GR3770 Master not sticking to drum et al

You are right

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

Did test code#62 on the blue drum and still only the big bottom roller will spin.

[Iowatech]

Re: Risograph GR3770 Master not sticking to drum et al

@Iowatech

Thanks. The small middle roller isn't spinning, but the big one at the bottom is. That roller on my other working drums spins so this must be the issue then huh. Any steps I should take to fix this?? Thanks!

Check the drive belt in the back of the drum to make sure it is OK. Also, one of the pulleys that the belt rides on kind looks like an idler pulley, but it actually drives a shaft that the ink bead forms around. I've seen that break a couple of times. You might check that, too.

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

Check the drive belt in the back of the drum to make sure it is OK. Also, one of the pulleys that the belt rides on kind looks like an idler pulley, but it actually drives a shaft that the ink bead forms around. I've seen that break a couple of times. You might check that, too.

Thanks again. I took off the plastic covering of the back and checked the belt w/o dismantling the whole drum. I'm comparing the broken drum to a working drum and everything seems to be functioning the same on both. The belt turns the small "drive shaft" from the outside looking through the back, but when I pinch the belt it doesn't spin as I look inside the drum thru the cartridge hole (it does rotate the driveshaft thing when I pinch the belt on the working drum). Very confused. Any further instruction would be great!

[Iowatech]

Re: Risograph GR3770 Master not sticking to drum et al

Thanks again. I took off the plastic covering of the back and checked the belt w/o dismantling the whole drum. I'm comparing the broken drum to a working drum and everything seems to be functioning the same on both. The belt turns the small "drive shaft" from the outside looking through the back, but when I pinch the belt it doesn't spin as I look inside the drum thru the cartridge hole (it does rotate the driveshaft thing when I pinch the belt on the working drum). Very confused. Any further instruction would be great!

I don't understand what you mean by "pinch the belt". Please elaborate.

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

I don't understand what you mean by "pinch the belt". Please elaborate.

Sorry, I mean I was playing with the belt, jiggling it a bit if you will. If I apply enough pressure it will move the other parts around as it should. The belt turns the thing connected to ink drive shaft on the outside, but it's not turning the actual drive shaft as I look in through the ink cartridge. Does that make sense?

[NONPOROUS]

Re: Risograph GR3770 Master not sticking to drum et al

Anything else that could be preventing the drive shaft from spinning?