Chapter 4 Contents
4-1 Electrophotographic system .......................................................................................................... 4-3
4-1-1 Electrophotographic cycle ......................................................................................................... 4-3
(1) Main charging ............................................................................................................................ 4-4
Components of drum and main charger unit................................................................................... 4-4
Amorphus-silicon drum ................................................................................................................... 4-5
Charging the drum .......................................................................................................................... 4-6
(2) Exposure ................................................................................................................................... 4-7
Laser scanner unit .......................................................................................................................... 4-8
Drum surface potential.................................................................................................................. 4-10
(3) Development ............................................................................................................................4-11
(4) Transfer ................................................................................................................................... 4-14
(5) Fusing...................................................................................................................................... 4-15
Fuser unit mechanism................................................................................................................... 4-16
(6) Cleaning .................................................................................................................................. 4-17
4-2 Paper feeding system.................................................................................................................... 4-18
4-2-1 Paper feed control ................................................................................................................... 4-19
(1) Paper feeding mechanism....................................................................................................... 4-20
Drive and paper feed unit.............................................................................................................. 4-20
MP tray paper feed unit................................................................................................................. 4-21
Fuser unit and face up/down output.............................................................................................. 4-22
4-3 Electrical control system .............................................................................................................. 4-23
4-3-1 Electrical parts layout .............................................................................................................. 4-23
(1) Circuit boards, sensors and switches ...................................................................................... 4-23
(2) Motors, solenoids, clutches and others ................................................................................... 4-24
(3) Drum unit and developer ......................................................................................................... 4-25
4-3-2 Operation of circuit boards ...................................................................................................... 4-26
(1) Main board............................................................................................................................... 4-26
(2) Engine board ........................................................................................................................... 4-27
Eraser lamp control circuit ............................................................................................................ 4-28
Toner motor control circuit............................................................................................................. 4-29
Heater lamp control circuit ............................................................................................................ 4-30
(3) Sensor board ........................................................................................................................... 4-32
Paper gauge sensing circuit.......................................................................................................... 4-32
Interlock circuit .............................................................................................................................. 4-33
Paper size detecting circuit ........................................................................................................... 4-35
(4) Power supply unit .................................................................................................................... 4-37
(5) High voltage unit...................................................................................................................... 4-38