Ricoh B205 Service Manual page 19

Fine Character and Image (FCI) .........................................................6-34
6.6 LASER EXPOSURE ................................................................................6-35
6.6.1 OVERVIEW ....................................................................................6-35
6.6.2 AUTO POWER CONTROL (APC) ..................................................6-36
6.6.3 LD SAFETY SWITCH .....................................................................6-37
6.7 PHOTOCONDUCTOR UNIT (PCU) ........................................................6-38
6.7.1 OVERVIEW ....................................................................................6-38
6.7.2 DRIVE.............................................................................................6-39
6.8 DRUM CHARGE .....................................................................................6-40
6.8.1 OVERVIEW ....................................................................................6-40
6.8.1 CHARGE ROLLER VOLTAGE CORRECTION ..............................6-41
Correction for Environmental Conditions ............................................6-41
6.8.2 ID SENSOR PATTERN PRODUCTION TIMING............................6-42
6.8.3 DRUM CHARGE ROLLER CLEANING ..........................................6-43
6.9 DEVELOPMENT .....................................................................................6-44
6.9.1 OVERVIEW ....................................................................................6-44
6.9.2 DRIVE.............................................................................................6-45
6.9.3 DEVELOPER MIXING ....................................................................6-46
6.9.4 DEVELOPMENT BIAS ...................................................................6-47
6.9.5 TONER SUPPLY ............................................................................6-48
Toner bottle replenishment mechanism ..............................................6-48
Toner supply mechanism....................................................................6-49
6.9.6 TONER DENSITY CONTROL ........................................................6-50
Overview .............................................................................................6-50
Toner density sensor initial setting......................................................6-52
Toner density measurement ...............................................................6-52
Vsp/Vsg detection ...............................................................................6-52
Toner supply reference voltage (Vref) determination ..........................6-52
Toner supply determination ................................................................6-52
Toner Supply Motor On Time Determinations.....................................6-53
6.9.7 TONER SUPPLY IN ABNORMAL SENSOR CONDITIONS ...........6-54
ID sensor ............................................................................................6-54
TD Sensor...........................................................................................6-54
6.9.8 TONER NEAR END/END DETECTION AND RECOVERY ............6-54
Toner Near End Detection ..................................................................6-54
Toner Near End Recovery ..................................................................6-55
Toner End Detection ...........................................................................6-55
Toner End Recovery ...........................................................................6-55
6.10 DRUM CLEANING AND TONER RECYCLING.....................................6-56
6.10.1 DRUM CLEANING........................................................................6-56
6.10.2 TONER RECYCLING ...................................................................6-57
6.11 PAPER FEED........................................................................................6-58
6.11.1 OVERVIEW ..................................................................................6-58
6.11.2 PAPER FEED DRIVE MECHANISM ............................................6-59
6.11.3 PAPER FEED AND SEPARATION MECHANISM........................6-60
6.11.4 PAPER LIFT MECHANISM ..........................................................6-61
6.11.5 PAPER END DETECTION ...........................................................6-63
6.11.6 PAPER HEIGHT DETECTION .....................................................6-64
6.11.7 FEED PRESSURE ADJUSTMENT FOR PAPER SIZE................6-66
SM vii B205/B209/D007/D008