HP LaserJet Enterprise 500 MFP M525 - Theory of operation; Basic operation; Formatter-control system

Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Major systems ........................................................................................................... 2
Product block diagram ............................................................................................... 2
Sequence of operation ............................................................................................... 3
Normal sequence of operation ..................................................................... 3
Formatter-control system ............................................................................................................ 4
Auto on/Auto off mode .............................................................................................. 4
Input/output ............................................................................................................. 6
CPU ........................................................................................................................ 6
Memory ................................................................................................................... 6
Firmware ................................................................................................... 6
Nonvolatile memory ................................................................................... 6
PJL overview ............................................................................................................. 6
PML ......................................................................................................................... 7
Control panel ........................................................................................................... 7
Engine-control system ................................................................................................................ 8
Motors, fans, clutches, solenoids, switches, and sensors ................................................. 9
DC controller operations .......................................................................................... 16
Fuser-control circuit .................................................................................................. 18
Fuser failure detection ............................................................................... 19
Fuser temperature control .......................................................................... 20
Fuser protective function ............................................................................ 21
Low-voltage power supply ........................................................................................ 22
Overcurrent/overvoltage protection ............................................................ 23
High-voltage power supply ....................................................................................... 24
Formatter ............................................................................................................... 25
Formatter heartbeat LED ............................................................................ 25
Laser/scanner system .............................................................................................. 26
Laser failure detection ............................................................................... 27
Image-formation system ........................................................................................................... 28
Electrophotographic process ..................................................................................... 28
ENWW v