There are retaining tabs on each side, but they will release themselves as you pull up on the cover. If there are none, remove the top-accessory cover (toward the back of the printer, on top) by simply lifting it up. Remove any output accessories (stacker, mailbox, etc.). Remove top accessories or top-accessory cover.Make sure to put the toner cartridge in a dark place or cover it – prolonged exposure to ambient light can damage the drum. Remove the toner cartridge and paper cassette.A step-by-step procedure follows (unless stated otherwise, left-right designations are as viewed from the front of the printer). Since the amount of work required is about the same, we recommend replacing the assembly. This shortcut is not available in the P4015 series, but it is still possible to replace either the main fuser drive gear or the entire fuser drive assembly. In the 4200/4300 printers, you could often get away with replacing just one gear (rather than the whole swing plate assembly), and there was a shortcut procedure for doing this. It is a similar design, and has similar problems, including a tendency for the gears in the fuser drive gear asm to wear out.

This series of printers is HP’s replacement for the LaserJet 4200/4300 series. Replacement Procedure for Fuser Drive Gear in the LaserJet P4015 series

Hp laserjet p4015n fuser assembly