Gestetner B147 Service Manual page 21

Fax Application (Transmission/Reception)..........................................6-37
6.6 LASER EXPOSURE................................................................................6-38
6.6.1 OVERVIEW ....................................................................................6-38
6.6.2 OPTICAL PATH..............................................................................6-39
6.6.3 LASER SYNCHRONIZING DETECTOR ........................................6-40
Overview.............................................................................................6-40
Main Scan Start Detection ..................................................................6-40
Clock Frequency Adjustment ..............................................................6-40
6.6.4 DUAL BEAM WRITING ..................................................................6-41
Dual Beam Mechanism.......................................................................6-41
Laser Beam Pitch Change Mechanism...............................................6-41
Printing Mode and Black LD Unit Position ..........................................6-42
6.6.5 LD SAFETY SWITCH .....................................................................6-43
Error Messages ..................................................................................6-44
6.6.6 AUTOMATIC LINE POSITION ADJUSTMENT ..............................6-45
Overview.............................................................................................6-45
Summary of Each Adjustment ............................................................6-46
Adjustment Conditions ........................................................................6-47
Main Scan Skew Adjustment ..............................................................6-48
6.6.7 DIFFERENCES IN THE COPY AND PRINTER MODES ...............6-48
6.7 PHOTOCONDUCTOR UNIT ...................................................................6-49
6.7.1 OVERVIEW ....................................................................................6-49
6.7.2 DRIVE.............................................................................................6-50
6.7.3 DRUM GEAR POSITION SENSORS .............................................6-51
Mechanism .........................................................................................6-51
Initialization Process and SC Codes ...................................................6-52
6.7.4 DRUM CHARGE AND QUENCHING .............................................6-53
6.7.5 DRUM CLEANING..........................................................................6-54
6.7.6 WASTE TONER COLLECTION .....................................................6-55
Waste Toner Path ...............................................................................6-55
Waste Toner Vibrator..........................................................................6-56
6.7.7 WASTE TONER BOTTLE FULL DETECTION ...............................6-57
6.8 DEVELOPMENT .....................................................................................6-58
6.8.1 OVERVIEW ....................................................................................6-58
6.8.2 DRIVE.............................................................................................6-59
6.8.3 DEVELOPER AGITATION .............................................................6-60
6.8.4 DEVELOPMENT BIAS ...................................................................6-61
6.8.5 TONER SUPPLY MECHANISM .....................................................6-62
Overview.............................................................................................6-62
Toner Agitation and Attraction ............................................................6-62
Air Flow and Toner Flow .....................................................................6-63
Toner Near End Detection ..................................................................6-63
Toner Transport ..................................................................................6-64
6.8.6 TONER CARTRIDGE DETECTION ...............................................6-65
6.9 PAPER FEED..........................................................................................6-66
6.9.1 OVERVIEW ....................................................................................6-66
6.9.2 DRIVE - TRAY 1, TRAY 2, AND BY-PASS TRAY .........................6-67
6.9.3 PAPER LIFT - TRAYS 1 & 2..........................................................6-68
6.9.4 PAPER SIZE DETECTION - TRAYS 1 & 2....................................6-69
SM ix B147/B149/B190