Table of contents
1 Theory of operation
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 ....................................................................................... 24
Image-formation system ..................................................................................................................... 25
Electrophotographic process ............................................................................................. 25
Image formation process ................................................................................................... 27
Latent-image formation block ............................................................................ 28
Pre-exposure .................................................................................... 28
ENWW iii
