HP LASERJET ENTERPRISE 700 M712 - Theory of Operation

Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Function structure ...................................................................................................... 2
Operation sequence .................................................................................................. 2
Engine control system ............................................................................................................... 4
DC controller PCA ..................................................................................................... 5
Motor control ............................................................................................. 6
Motor locations ........................................................................... 7
Failure detection ......................................................................... 7
Fan control ................................................................................................ 8
Fan locations .............................................................................. 9
Failure detection ......................................................................... 9
Low-voltage power-supply PCA ................................................................................. 10
Over-current/over-voltage/overload protection ............................................ 11
Safety interruption .................................................................................... 11
Power supply voltage detection .................................................................. 11
Sleep mode ............................................................................................. 12
Power supply illumination control ............................................................... 12
High-voltage power-supply PCA ................................................................................ 13
Fuser control ........................................................................................................... 15
Fuser temperature control .......................................................................... 17
Fuser heater protective function .................................................................. 17
Fuser failure detection ............................................................................... 18
Pressure roller cleaning ............................................................................. 19
Laser scanner system .............................................................................................................. 20
Laser scanner failure detection .................................................................................. 21
Laser scanner safety function .................................................................................... 21
Image-formation system ........................................................................................................... 22
Image-formation process .......................................................................................... 23
Latent-image formation block ..................................................................... 24
Step 1: primary charging ........................................................... 24
Step 2: laser-beam exposure ....................................................... 25
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