Basic operation of the printer..............................................................................................105 Printer operating sequence................................................................................105 Control system overview.....................................................................................................105 Pickup-and-feed system overview......................................................................................106 Laser/scanner system overview.........................................................................................106 Image-formation system overview......................................................................................106 General descriptions ...........................................................................................................................107 Dc controller PCA...............................................................................................................108 Motor and fan control.........................................................................................109 Power supply......................................................................................................................110 Fuser-control circuit............................................................................................110 Fuser over-temperature protection ...................................................................111 Overcurrent/overvoltage protection....................................................................111 Laser/scanner assembly.....................................................................................................112 Paper-pickup-and-feed system...........................................................................................................114 Pickup-and-feed block .......................................................................................................116 Printing from tray 1 .............................................................................................................117 Printing from tray 2 .............................................................................................................119 Tray 2, 500-sheet feeder, and 1,500-sheet feeder media-size detection..........119 Lifter-driver operation.........................................................................................120 Multiple-feed prevention.....................................................................................121 Media-skew prevention.......................................................................................................121 Fuser/delivery block............................................................................................................122 Jam detection......................................................................................................................122 Printer pickup delay jam from tray 1..................................................................123 Printer pickup delay jam from tray 2..................................................................123 Printer pickup stationary jam..............................................................................123 Printer-delivery wrap jam when feeding regular media.....................................123 Printer delivery wrap-jam when feeding irregular media...................................123 Printer delivery-delay jams.................................................................................124 Printer door-open jam .......................................................................................124 Printer residual-media jam.................................................................................124 Printing from the 500-sheet feeder.....................................................................................125 500-sheet feeder pickup and feeding................................................................126 Printing from the 1,500-sheet feeder..................................................................................128 1,500-sheet feeder pickup and feeding.............................................................129 1,500-sheet feeder lifting mechanism................................................................131 Envelope feeder..................................................................................................................132 Envelope-feeder pickup and feeding.................................................................132 Envelope feeder jam detection ..........................................................................................133 Envelope feeder pickup delay jam.....................................................................133 Envelope feeder pickup stationary jam..............................................................133 Duplexer..............................................................................................................................134 Reversing and duplexer pickup..........................................................................135 Duplexer jam detection ......................................................................................................136 Stacker and stapler/stacker ................................................................................................................137 Stacker................................................................................................................................139 Stacker feed and delivery..................................................................................139 Stacker jam detection.........................................................................................................141 Stacker-feed jam ...............................................................................................141 vi