7.1 Construction ...................................................................................................................................................................7-1

7.1.1 Overview...................................................................................................................................................................................... 7-1

7.1.2 Major Components....................................................................................................................................................................... 7-1

7.2 Image Formation Process...............................................................................................................................................7-2

7.2.1 Overview...................................................................................................................................................................................... 7-2

7.3 Basic Sequence ..............................................................................................................................................................7-3

7.3.1 At Power-On ................................................................................................................................................................................ 7-3

7.3.2 At Time of Printing ...................................................................................................................................................................... 7-3

7.4 Potential Control ............................................................................................................................................................7-5

7.4.1 Overview...................................................................................................................................................................................... 7-5

7.4.2 Copier/Printer Potential Control .................................................................................................................................................. 7-5

7.4.3 Determining the Primary Current ................................................................................................................................................ 7-7

7.4.4 Determining the Laser Output ..................................................................................................................................................... 7-8

7.4.5 Determining the Developing Bias................................................................................................................................................ 7-8

7.4.6 APC Correction............................................................................................................................................................................ 7-9

7.4.7 Adjusting the Density in Various Modes................................................................................................................................... 7-10

7.5 Charging Mechanism ...................................................................................................................................................7-11

7.5.1 Controlling Pre-Exposure LED.................................................................................................................................................. 7-11

7.5.1.1 Pre-Exposure LED Control ...........................................................................................................................................................................7-11

7.5.2 Primary Charging Mechanism ................................................................................................................................................... 7-11

7.5.2.1 Overview .......................................................................................................................................................................................................7-11

7.5.2.2 Primary Charging Assembly Cleaning Mechanism ......................................................................................................................................7-11

7.5.2.3 Others ............................................................................................................................................................................................................7-12

7.5.3 Dust-Collecting Roller Bias ....................................................................................................................................................... 7-12

7.5.3.1 Overview .......................................................................................................................................................................................................7-12

7.5.4 Pre-Transfer Charging Mechanism............................................................................................................................................ 7-13

7.5.4.1 Outline...........................................................................................................................................................................................................7-13

7.5.4.2 Controlling the Output to Suit the Environment (fuzzy control) ..................................................................................................................7-13

7.5.4.3 Pre-Transfer Charging Assembly Cleaning Mechanism...............................................................................................................................7-14

7.5.4.4 Others ............................................................................................................................................................................................................7-14

7.6 Drum Cleaner Unit.......................................................................................................................................................7-16

7.6.1 Outline........................................................................................................................................................................................ 7-16

7.6.2 Detecting the State (full) of the Waste Toner Case ................................................................................................................... 7-16

7.7 Developing Assembly ..................................................................................................................................................7-18

7.7.1 Controlling the Developing Assembly Drive ............................................................................................................................ 7-18

7.7.2 Controlling the Developing Bias ............................................................................................................................................... 7-18

7.7.3 Detecting the Toner Level and Controlling Toner Supply ........................................................................................................ 7-19

7.8 Transfer Mechanism ....................................................................................................................................................7-21

7.8.1 Transfer Charging Mechanism .................................................................................................................................................. 7-21

7.8.1.1 Outline...........................................................................................................................................................................................................7-21

7.8.1.2 Controlling the Output to Suit the Environment (fuzzy control) ..................................................................................................................7-21

7.8.1.3 Transfer Charging Assembly Cleaning Mechanism .....................................................................................................................................7-21

7.8.1.4 Others ............................................................................................................................................................................................................7-22

7.9 Separation Mechanism .................................................................................................................................................7-23

7.9.1 Separation Charging Mechanism ............................................................................................................................................... 7-23

7.9.1.1 Outline...........................................................................................................................................................................................................7-23

7.9.1.2 Correcting the Output to Suit the Environment and the Drum Surface Potential .........................................................................................7-23

7.9.1.3 Others ............................................................................................................................................................................................................7-24

7.10 Parts Replacement Procedure.....................................................................................................................................7-25

7.10.1 Process Unit ............................................................................................................................................................................. 7-25

7.10.1.1 Removing the Primary Fan Duct.................................................................................................................................................................7-25

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