Printer (product base) functions ......................................................................................................... 74 Engine control system (engine control unit and power-supply assembly) ......................... 75 Print-engine control system ............................................................................... 75 Printer (product base) laser/scanner ................................................................. 76 Power system on the power-supply assembly .................................................. 77 Ac power distribution ........................................................................
77 Dc power distribution ........................................................................ 77 Overcurrent/overvoltage ................................................................... 77 High-voltage power distribution ........................................................ 78 Image-formation system .................................................................................................... 79 The seven image-formation processes ............................................................ 79 Print cartridge ....................................................................................................................
80 Printer (product base) paper-feed system ......................................................................... 80 Jam detection in the all-in-one .......................................................................................... 82 Conditions of jam detection ............................................................................... 82 HP LaserJet 3050 all-in-one unique components .............................................................................. 83 Basic operation ..................................................................................................................
83 ADF pickup-and-feed system ............................................................................ 85 Optical scanning system ................................................................................... 87 HP LaserJet 3052/3055 all-in-one unique components ..................................................................... 89 Scanner and ADF functions and operation ........................................................................ 89 Scanner functions ............................................................................................ 89 Scanner operation .............................................................................................
90 ADF operation ................................................................................................... 90 ADF paper path and ADF sensors .................................................................... 91 ADF jam detection ............................................................................................. 91 Fax functions and operation (HP LaserJet 3050 all-in-one and HP LaserJet 3055 all-in-one only) .................................................................................................................................................... 92 Computer and network security features ...........................................................................
92 PSTN operation ................................................................................................................. 92 Distinctive ring function ...................................................................................................... 93 Faxing with Voice over IP services .................................................................................... 94 The fax subsystem ............................................................................................................. 94 Formatter in the fax subsystem .........................................................................................
94 LIU in the fax subsystem ................................................................................................... 95 Safety isolation .................................................................................................. 95 Safety-protection circuitry .................................................................................. 95 Data path ........................................................................................................... 96 Hook state .........................................................................................................
96 Downstream current detection .......................................................................... 96 Hook switch control ........................................................................................... 97 Ring detect ........................................................................................................ 97 Line-current control ........................................................................................... 97 Billing- (metering-) tone filters ........................................................................... 97 Fax page storage in flash memory ....................................................................................
98 Stored fax pages ............................................................................................... 98 Advantages of flash-memory storage .............................................................. 98 5 Removal and replacement Removal and replacement strategy .................................................................................................. 100 vi ENWW