Installing memory and font DIMMs .........................................................................................79 Enabling memory ..............................................................................................................83 Enabling the language font DIMM (HP color LaserJet 3700 only) ...................................83 Checking DIMM installation (HP color LaserJet 3700 only) .............................................84 Installing an HP Jetdirect print server card in the HP color LaserJet 3700 series printer ......85 To install the HP Jetdirect print server card .....................................................................85 Installing an HP Jetdirect en3700 external print server ..........................................................88 4 Printer maintenance Chapter contents .....................................................................................................................91 Cleaning the printer and accessories ......................................................................................92 Cleaning spilled toner .......................................................................................................92 Managing supplies ..................................................................................................................94 Supplies life ......................................................................................................................94 Approximate replacement intervals for supplies for the HP Color LaserJet 3500 series printer ..................................................................................................................94 Approximate replacement intervals for supplies for the HP Color LaserJet 3550/3700 series printer ................................................................................................94 Locating supplies and parts ....................................................................................................96 Replacing supply items ...........................................................................................................97 Replacing the transfer unit ................................................................................................99 Replacing the fuser and pickup roller .............................................................................103 5 Theory of operation Chapter contents ...................................................................................................................113 Basic operation .....................................................................................................................114 Operation sequence .......................................................................................................114 Power-on sequences ......................................................................................................116 Engine control system ...........................................................................................................119 DC controller PCB ..........................................................................................................119 Low-voltage power supply circuit ...................................................................................126 Low-voltage power supply circuit ...................................................................................131 Laser/scanner system ...........................................................................................................139 Laser control ...................................................................................................................140 Scanner motor control ....................................................................................................144 Image formation system ........................................................................................................146 Print process ...................................................................................................................147 Developing section .........................................................................................................156 Cartridge cleaning control ...............................................................................................163 Transfer section ..............................................................................................................164 ITB cleaning control ........................................................................................................167 Waste toner full detection ...............................................................................................167 Transfer (ITB) unit detection ...........................................................................................168 Transfer unit life detection ..............................................................................................169 ITB self-aligning mechanism ..........................................................................................170 Primary transfer roller engaging/disengaging control ....................................................171 Secondary transfer roller engaging/disengaging control ................................................172 Secondary transfer roller engaging/disengaging detection ............................................173 Color misregistration control ...........................................................................................174 Image stabilization control ..............................................................................................177 Pickup/feed system ...............................................................................................................182 Pickup/feed unit ..............................................................................................................184 Fuser/delivery unit ..........................................................................................................189 Duplexing feed unit (HP 3700 printer only) ....................................................................192 Jam detection .................................................................................................................195 ENWW Conventions vii