Constant paper jams when printing large doc...

check that you are using a suitable paper NOT all paper qualities work in printers, some are too smooth to be collected vai the rollers.

The other thing to check is the paper has been pre fanned like frpppppng playing cards to ensure they are not sticking to each other.

Also clean excess ink or toner off the rollers regularly with alcohol and even run a plastic mit over them to rouchen them up and reduce shine which causes slippage and jambs