HP LaserJet Enterprise M4555 - Page 7

Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Sequence of operation (product) ................................................................................. 2
Sequence of operation (scanner) ................................................................................. 3
Formatter-control system ............................................................................................................ 4
Sleep delay .............................................................................................................. 4
Image Resolution Enhancement technology ................................................................... 4
Input/output ............................................................................................................. 5
Memory ................................................................................................................... 5
Hard disk .................................................................................................. 5
Random-access memory .............................................................................. 5
Firmware ................................................................................................... 5
Nonvolatile memory ................................................................................... 5
HP Memory Enhancement technology ........................................................... 6
CPU ......................................................................................................... 6
PJL overview ............................................................................................................. 6
PML ......................................................................................................................... 6
Control panel ........................................................................................................... 6
Scanner interface ...................................................................................................... 6
Engine-control system ................................................................................................................ 7
DC controller PCA ..................................................................................................... 7
Motors and fans ........................................................................................................ 8
Motor and fan functions .............................................................................. 9
Ambient-temperature detection ................................................................... 10
High-voltage power supply ....................................................................................... 11
Fuser control ........................................................................................................... 12
Fuser temperature control .......................................................................... 13
Fuser failure detection ............................................................................... 14
Other functions ........................................................................................ 15
Low-voltage power supply ........................................................................................ 16
Overcurrent/overvoltage protection ............................................................ 17
Safety ..................................................................................................... 17
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