HP M750 series - Theory of Operation

Table of contents
1 Theory of operation ....................................................................................................................................... 1
Basic operation ...................................................................................................................................................... 2
Major product systems ........................................................................................................................ 2
Product block diagram ........................................................................................................................ 2
Sequence of operation ........................................................................................................................ 3
Normal sequence of operation ......................................................................................... 3
Formatter-control system ..................................................................................................................................... 5
Sleep mode .......................................................................................................................................... 5
Input/output ........................................................................................................................................ 5
CPU ....................................................................................................................................................... 6
Memory ................................................................................................................................................ 6
Firmware ........................................................................................................................... 6
Nonvolatile memory ......................................................................................................... 6
PJL overview ........................................................................................................................................ 6
PML ...................................................................................................................................................... 6
Control panel ....................................................................................................................................... 6
Engine-control system .......................................................................................................................................... 7
DC controller ........................................................................................................................................ 8
Motors ............................................................................................................................. 11
Fans ................................................................................................................................. 13
Fuser-control circuit ....................................................................................................... 14
Fuser temperature control ........................................................................... 15
Fuser protective function ............................................................................. 16
Fuser failure detection ................................................................................. 17
Low-voltage power supply ............................................................................................. 18
Overcurrent/overvoltage protection ........................................................... 20
High-voltage power supply ............................................................................................ 21
Laser scanner system ....................................................................................................................... 23
Laser failure detection .................................................................................................... 23
Image-formation system .................................................................................................................................... 25
Electrophotographic process ............................................................................................................ 25
Image formation process .................................................................................................................. 27
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