HP LASERJET ENTERPRISE 500 - Page 7

Table of contents
1 Theory of operation .......................................................................................................... 1
Basic operation ........................................................................................................................ 2
Sequence of operation ............................................................................................... 3
Engine control system ............................................................................................................... 4
DC controller ............................................................................................................ 5
Solenoids .................................................................................................. 6
Clutches .................................................................................................... 6
Switches ................................................................................................... 6
Sensors ..................................................................................................... 7
Motors and fans ......................................................................................... 7
High voltage power supply ...................................................................................... 10
Low voltage power supply ........................................................................................ 12
Overcurrent/overvoltage protection ............................................................ 14
Safety ..................................................................................................... 14
Sleep (powersave) mode ........................................................................... 14
Power supply voltage detection .................................................................. 14
Low voltage power supply failure ............................................................... 14
Power off condition .................................................................................. 15
Fuser control ........................................................................................................... 15
Fuser temperature control circuit ................................................................. 16
Fuser over temperature protection ............................................................... 17
Fuser failure detection ............................................................................... 18
Laser/scanner system ............................................................................................................. 19
Image formation system .......................................................................................................... 21
Image formation process .......................................................................................... 22
Step 1: Pre-exposure ................................................................................. 23
Step 2: Primary charging .......................................................................... 23
Step 3: Laser-beam exposure ..................................................................... 24
Step 4: Development ................................................................................ 24
Step 5: Primary transfer ............................................................................ 25
Step 6: Secondary transfer ........................................................................ 25
Step 7: Separation ................................................................................... 26
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