Stacker-feed stationary jam...............................................................................141 Stacker residual-media jam...............................................................................141 Stapler/stacker ...................................................................................................................142 Stapler/stacker feed and delivery.......................................................................142 Staple-mode feed and delivery..........................................................................144 Stapler unit.........................................................................................................148 Stapler-unit operation ........................................................................................149 Staple level-detection.........................................................................................151 Stack-mode feed and delivery...........................................................................151 Stapler/stacker jam detection ............................................................................................152 Stapler/stacker feed jam ...................................................................................152 Stapler/stacker feed stationary jam....................................................................152 Stapler/stacker delivery jam...............................................................................152 Stapler/stacker residual media jam....................................................................152 Image-formation system .....................................................................................................................153 Electrostatic latent-image formation...................................................................................155 Primary charging ...............................................................................................155 Writing the image ..............................................................................................155 Developing the image .......................................................................................156 Transferring the image ......................................................................................157 Fusing the image ...............................................................................................158 Cleaning the transfer charging roller and photosensitive drum.........................159 Print-cartridge memory chip...............................................................................160 Formatter system.................................................................................................................................161 PowerSave (LJ 4200/4200L/4300) or Sleep (LJ 4250/4350) Mode...................................161 Resolution Enhancement technology ...............................................................................162 EconoMode ........................................................................................................................162 Input/output.........................................................................................................................162 Parallel interface................................................................................................162 USB (HP LaserJet 4250/4350 Series printers only)..........................................162 Embedded ethernet print server (HP LaserJet 4250/4350 Series printers only)....................................................................................................................162 Expanded I/O.....................................................................................................163 Flash (HP LaserJet 4200/4300 Series printers only).........................................163 CompactFlash card (HP LaserJet 4250/4350 Series printers only)..................163 Hard-disk accessory...........................................................................................163 CPU ...................................................................................................................163 Printer memory ..................................................................................................................163 Read-only memory ............................................................................................163 Random-access memory ..................................................................................163 DIMM slots .......................................................................................................164 Firmware DIMM (LJ 4200/4200L/4300 only).....................................................164 Nonvolatile memory...........................................................................................164 Memory Enhancement technology ...................................................................164 PJL overview .....................................................................................................................164 PML.....................................................................................................................................165 Control panel ......................................................................................................................165 6 Removing and replacing parts Chapter contents.................................................................................................................................167 vii