When lifted, you will be able to rotate these drums in one direction. When printing, they are dropped to the top of the paper stack and will engage to separate the topmost sheet off the stack. When not printing, these drums are lifted. It looks like there is too much play in the paper pick-up unit (at the rightmost end inside the printer) on which both pick-up drums are mounted on a single arm. You most likely hear a grinding noise of plastic cogwheels slipping when the printer tries to feed a sheet of paper. Scenario 1: the pick-up drums do not roll, you hear a grinding noise Thanks much for steering me in the right direction. My printer had little use as I have a second one that I use for everyday printing, so, wanted to save the hp 310 as my good scanner/color/printer. Now works great! Hardest part was manipulating the dabbing of the epoxy on the spline due to working with mirror image. Waited until next morning to try printer. Very carefully slid the gear with fingers back on the shaft spline viewing that it was centered on the mating gear.

Mixed some two part epoxy and carefully dabbed small amount on the shaft spline until about 100% coated. Then slid the gear down & off the spline. (can move the gear by hand back in line with the gear train and try once to see if it fixes problem). One small plastic gear slid off the steel shaft 'spline' not engaging drive train. Taped drop light to now top of printer looking at the mirror/gear train. Positioned small flat mirror angled on its edge to view gear train.

Canon mp210 printer paper feed problem