RISO RP 3700 DIY service

[mixedfeelings]

aye, that you did. that you did.

I will try swapping the brakes out tonight! thanks!

[mixedfeelings]

OK! I swapped the brakes, cleaned all three rollers with martin yale rubber rejuvenator, and even replaced the clamp / projection assembly on my drum (it's been causing me problems, and probably wasn't helping the situation at all) and everything is working again! I am making masters and I seem to be exactly back where I was before my main drive gave out - which means all I have left is this persistent clockwise skew.

I checked the master, and the image on the master, and both seem to be perfect which leaves me to suspect the feed. I've leveled my feed tray and tried every possible combination of guide plate parallelism and spring tension. no matter what I get varying degrees of clockwise skew. I have it at the best setting I found, which still has me off by about 2mm.

Are there any other ways to affect paper feed besides those?

Thanks!

[jermyth]

Hummmm, is the master on the drum getting skewed, pulled? If so then it might be uneven pressure in the drum, the squeege roller. Or uneven pressure of the impression roller on the drum. I recall you replaced the impression roller, so I wont suggest that. It might even be too much pressure is being applied to the drum from the impression roller.

[mixedfeelings]

i measured the top and bottom of the master from the F side, and they were both 6mm away from the shiny metal border of the drum screen. I then measured the center line of my alignment image to the end of the master, and it seemed pretty on as well - but master misalignment is pretty common, no?

[jermyth]

Feed problems are usally more straight forward. Paper path is a straight shot. Maybe something is bent out of normal shape causing the skew. Either drum related or paper feed. Now is it correct that the 1st sheet printed is skewed, the proof copy?

[20gaugeO/U]

Use 11x17 paper and run the checkerboard pattern in TM. Measure the first checkerboard line of the lead edge on the drum front and rear to some point of your choosing going towards the clamp plate. Is it square? If yes, then it's w optics/scanner. If no, then something in the Master Making Unit. Anything rubber could be swollen.

Does your RP have a NIC card? Print to it?

May be simpler to shim the paper stop on the glass some how.

Riso's have a +-2mm tolerance for registration so you may be fighting a battle on an old machine you can never win.

[mixedfeelings]

I will double check - but i believe so. Another thing I have noticed is that when the paper is in the feed try there is a slight gap on the left side of the shhet between the sheet and the wall - it's unavoidable with the walls tight on the paper. Is there a way to micro adjust the feedwalls?

[mixedfeelings]

I pretty exclusively print to the GDI - haven't used the glass top in years. Perhaps I should look into replacing all of the master rollers...

Thanks!