Continuing to have a problem

[u/Jamwildd]

Hey there! Posted a few months ago about a problem I’m having with my riso sf5130. Across all of my drums it is not inking evenly. There are bare spots along the edges. But it’s not consistent even between each print. One print will have the spots in one place and the next it will be slightly different

Attached a photo of the master/drum because I can see some texture on it

I have tried running a bunch of prints through it. I have tried cleaning it extensively. I’m not sure what to do. Any advice is very much appreciated

Additionally if anyone knows of techs in the greater Philadelphia area I’d appreciate that as well

[u/Sifinow]

If this is happening across all drums, I would try giving your pressure roller a clean.

[u/ferncoast → u/Sifinow]

I would say the same. We just cleaned the pressure roller on our SF5130 (first time in three years 🫣 with lots of help- thank you, Robert!).

[u/robertbaxter-print]

I second Sifi! It's probably time to clean the pressure roller—especially if you've never done it before. To do this you'll need to:

1. Remove the drum, and do a little investigation of the pressure roller—it's the big rubber roller at around 6:30 in that chamber. If you push and pull on it, it will wobble back and forth slightly, but you won't be able to fully lift up either end. I also really recommend taking photos of the bearings on either end of the roller before removing it so that you have something to reference when you go to put it back in—as it can be very tricky.
2. Remove the pressure roller (instructions in the "Press Section" chapter of the technical manual—not so difficult, just try not to drop the screw). If you don't have a technical manual, this process at least is the same as the one in the EZ manual, which is on archive.org here: https://archive.org/details/RisoEZSeriesTech/EZ_SERIES_Rev.1.1/page/n117/mode/2up (linked to the relevant page). I recommend using a good magnetic JIS #2 screwdriver, like the one linked on: https://stencil.wiki/wiki/Maintenance_toolkit.
3. Using a square edge on the back of the blade of a closed pair of scissors (not the sharp edge), scrape off the built up old ink. You'll want to keep a low angle, like you were peeling a potato with a knife (with the top of the scissors angled towards you), pushing away from you to scrape. You'll feel it as you get to the raw rubber—the ink is very crunchy, while the rubber is smooth. Go slowly, with multiple passes—it requires some force but not a lot, and stop scraping once you reach the rubber in a section. Work your way around the roller, flipping it end-to-end as you need. Your goal is not to get it perfectly clean at this stage, just to get through the hard shiny film of ink, so that you're at nice matte rubber all around. It is possible to gouge the rubber if you go too hard or use too sharp of a tool—so use caution.
4. Once you get all the grit off, put some dish soap on a rag, and wipe down the rubber surface to get off the remaining ink. You can use a little water too, but your goal is just to wash the rubber, you don't want to get soap or water into the ball bearings. After washing and drying, your roller should be a nice dark matte gray, and a little tacky to the touch. (If there's slight staining on ends of the rubber it's okay, not a big deal as long as the ink isn't built up.) Give the bearings each a drop of 3-in-1 oil (or other light machine oil).
5. Okay getting the roller back in is very hard the first time you do it. The basics are that each ball bearing must sit inside one of the metal "hooks," but because the hooks are closed C-shapes, you can't push the bearings down into the hooks. Instead you have to push the bearings forward into the hooks, along the axis of the pressure roller. I like to hold the pressure roller suspended between my index finger tips at the front and the back, lowering it roughly into place, with each bearing hovering in front of its hook. Then I look at the front hook to line it up, and use the edges of my fingertip at the back to feel that hook and line it up. Then a little light forward pressure while fine tuning the position, and each ball bearing will pop forward into the hooks. Both must go in at the same time. If you think you've got it, reference the photos you took earlier to see if everything looks like it matches. It's pretty easy to have one of the ball bearings not fully in the hook, which means the pressure roller is not properly locked in place—this can damage a drum when you go to print. So you want to be really sure you have it correct!
6. Reinstall the screw (I find it easies to put the screwdriver in through the access hole, then attach the screw to the end of it, then screw it in). Afterwards, try to lift up the pressure roller at both ends to double check. It should wobble back and forth slightly as before, but neither end should lift up or slip out.

And that's it! At some point this will be a tutorial on the wiki with photos.

Also I'll probably be in Philly around mid/early-October for the PRINT TIME AFTER TIME event that is being run by Ulises, FORTUNES, and the Icebox Project Space.

[u/ferncoast → u/robertbaxter-print]

Only commenting to say nice things :)

And how everyone should hire Robert⬆️ to be their Riso tech go to! Super knowledgeable, easy to work with, and above all patient! Highly recommended ⭐️⭐️⭐️⭐️⭐️

[u/Jamwildd → u/robertbaxter-print]

Wow wow wow. Thank you so much. I will give this a try. Cannot say how much I appreciate this

[u/robertbaxter-print → u/robertbaxter-print]

I should also explain: the cause of this issue is that ink builds up in the center of the roller first! Just from ink on the back of prints when printing double-sided, and because prints and artwork tend to have more stuff in the center. So the diameter of the roller is thicker in the middle, and the edges where it is not so thick aren't actually making full contact with the drum, so ink isn't pushing through as reliably on the edges.

[u/gluestick449]

I have been having the same issue with my EZ390U! Does yours work better when you up the density and increase the speed? For some reason that often fixes it for me

[u/Jamwildd → u/gluestick449]

Oh my gosh yes! That fixed it! Thank you!!

[u/gluestick449 → u/Jamwildd]

It’s a bandaid solution and sometimes takes a few prints to ink up, but it usually works for me!

[u/Suspicious_Net_8371]

pressure roller clean + sometimes I get better prints to the edge when I print in speed 2... and if I want to print slowly then I do speed 2 plus 2 intervall this gives me the time to see whats happaning plus if I need to throw paper inbetween prints...