5.1 Construction ...................................................................................................................................................................5-1

5.1.1 Specifications, Control Mechanisms, and Functions ................................................................................................................... 5-1

5.1.2 Major Components....................................................................................................................................................................... 5-1

5.1.3 Construction of the Control System............................................................................................................................................. 5-2

5.1.4 Reader Controller PCB ................................................................................................................................................................ 5-3

5.2 Basic Sequence ..............................................................................................................................................................5-4

5.2.1 Basic Sequence of Operation at Power-On.................................................................................................................................. 5-4

5.2.2 Basic Sequence of Operation in Response to a Press on the Start Key (book mode; 1 original) ................................................ 5-4

5.2.3 Basic Sequence of Operation in Response to a Press on the Start Key (ADF mode; 1 original ) ............................................... 5-5

5.3 Various Control..............................................................................................................................................................5-6

5.3.1 Controlling the Scanner Drive System ........................................................................................................................................ 5-6

5.3.1.1 Outline.............................................................................................................................................................................................................5-6

5.3.1.2 Controlling the Reader Motor .........................................................................................................................................................................5-6

5.3.2 Contact Image Sensor (CIS) ........................................................................................................................................................ 5-7

5.3.2.1 Outline.............................................................................................................................................................................................................5-7

5.3.2.2 Analog Control Inside the Contact Image Sensor...........................................................................................................................................5-8

5.3.3 Enlargement/Reduction................................................................................................................................................................ 5-9

5.3.3.1 Changing the Magnification in Main Scanning Direction ..............................................................................................................................5-9

5.3.3.2 Varying the Magnification in Sub Scanning Direction...................................................................................................................................5-9

5.3.4 Detecting the Size of Originals .................................................................................................................................................... 5-9

5.3.4.1 Outline.............................................................................................................................................................................................................5-9

5.3.4.2 Outline of Size Identification ........................................................................................................................................................................5-10

5.3.5 Dirt Sensor Control .................................................................................................................................................................... 5-11

5.3.5.1 Outline...........................................................................................................................................................................................................5-11

5.3.6 Image Processing ....................................................................................................................................................................... 5-13

5.3.6.1 Outline...........................................................................................................................................................................................................5-13

5.3.6.2 CCD Drive ....................................................................................................................................................................................................5-14

5.3.6.3 Gain Correction and Offset Correction of the CCD Output .........................................................................................................................5-14

5.3.6.4 A/D Conversion of the CCD Output.............................................................................................................................................................5-14

5.3.6.5 Shading Correction (outline).........................................................................................................................................................................5-14

5.3.6.6 Shading Adjustment ......................................................................................................................................................................................5-14

5.3.6.7 Shading Correction........................................................................................................................................................................................5-15

5.4 Parts Replacement Procedure.......................................................................................................................................5-15

5.4.1 Copyboard glass......................................................................................................................................................................... 5-15

5.4.1.1 Removing the Copyboard Glass....................................................................................................................................................................5-15

5.4.1.2 Removing the ADF Reading Glass ...............................................................................................................................................................5-15

5.4.2 Reader Controller PCB .............................................................................................................................................................. 5-15

5.4.2.1 Before Replacing the Reader Controller PCB ..............................................................................................................................................5-15

5.4.2.2 Removing the Reader Rear Cover.................................................................................................................................................................5-16

5.4.2.3 Removing the rear cover of the machine ......................................................................................................................................................5-16

5.4.2.4 Removing the flexible cable cover................................................................................................................................................................5-16

5.4.2.5 Removing the Copyboard Glass....................................................................................................................................................................5-16

5.4.2.6 Removing the Reader Controller PCB..........................................................................................................................................................5-17

5.4.2.7 After Replacing the Reader Controller PCB or After Initializing the RAM.................................................................................................5-18

5.4.3 Scanner Motor............................................................................................................................................................................ 5-19

5.4.3.1 Removing the Reader Rear Cover.................................................................................................................................................................5-19

5.4.3.2 Removing the Scanner Motor .......................................................................................................................................................................5-19

5.4.4 Contact sensor ............................................................................................................................................................................ 5-19

5.4.4.1 Removing the Reader Front Cover ...............................................................................................................................................................5-19

5.4.4.2 Removing the Reader Rear Cover.................................................................................................................................................................5-20

5.4.4.3 Removing the Copyboard Glass....................................................................................................................................................................5-20

5.4.4.4 Removing the Contact Image Sensor (CIS) ..................................................................................................................................................5-21

5.4.4.5 After Replacement of the CIS .......................................................................................................................................................................5-21

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