Ah, the good ol' HP 1100 series. I had (still have actually) a beloved 1120C. Those things rocked!
Anyway, yeah, when they get old they start grabbing too much paper. Part of this is due to them being worn out. Also, the rollers start to get permeated with dust and gunk.
You have 2 options (or at least, 2 options I've found to work).
1. Buy new rollers
2. Clean that sucker to beyond surgical cleanliness. (doesn't always work)
Of course, for the price of printers today, you could just buy a new one.