Erratic stapling @ Ricoh 2075 ST

[Dexor]

When I try to staple lets say 5 sheets, most of the time, but not always, it would staple only 3 or 4, and sheets first and last are usually not stapled. Sometimes it would staple just fine, but more often than not - I have this problem.
I looked at jammed staples, lubed the plunger area, rails, bushings - no change.
Any ideas?

[TonerMunkeh]

Change the sponge tapping roller that sits above the stape tray, it gives the stacked paper in the jogger fences a tap to make sure they're all set straight. When they get worn, you get erratic stapling. Change the rubber belt at the same time too.

[Syscopiers]

Check the springs on the idle rollers in section "R-4" of the finisher. Usually a spring comes off causing uneven pressure. This is usually the cause of the problem on the machines i've encountered.

[Dexor]

thanks guys for your input/solutions. It turned out to be worn-out belt on sponge roller, which also came loose. I know I will have to replace it, but it's working for now. I will also check the springs on the idle rollers in R4.
Much appreciate!