HP 97 paper advance rollers

[Dave Britten]

I got the o-rings in the mail today. The results are encouraging, but it's going to need some tweaking to be usable. The inner and outer diameter seem perfect, but these rings are narrower than the original rollers. I was able to fit one ring on the outside of the center ribs on the plastic hubs, but there's not enough room on the inside of the rib to fit another o-ring. The originals would extend over this rib and cover nearly the whole plastic hub, as there was a channel inside the old rollers that would mesh with this rib.

As such, the replacement o-rings aren't providing as much grip, and not advancing the paper a full line with each advance (but they are moving the paper a bit). There also appears to be some tendency for the o-rings to "walk" toward the edges of the hub, though they don't fall off entirely, as other parts in the printer prevent them from having room to do so.

Maybe if I can find some small, non-metallic washers with a big-enough inner diameter, I could glue an o-ring onto each side and get them to straddle the rib properly. I also might need to slice the o-ring that goes inside the rib in half so that it doesn't hang too far past the inside edge of the plastic hub and bump the print head, or grip the ratchet teeth on the right hub.