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

5.1.1 Specifications/controls/functions ................................................................................................................................................. 5-1

5.1.2 Major Components....................................................................................................................................................................... 5-2

5.1.3 Configuration of Control System................................................................................................................................................. 5-3

5.1.4 Reader Controller PCB ................................................................................................................................................................ 5-4

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

5.2.1 Basic Sequence at Power-On ....................................................................................................................................................... 5-5

5.2.2 Basic Sequence at Start Key ON (book mode/1 original) ........................................................................................................... 5-5

5.2.3 Basic Sequence at Start Key ON (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 Overview .........................................................................................................................................................................................................5-6

5.3.1.2 Scanner Motor Control....................................................................................................................................................................................5-6

5.3.2 CCD ............................................................................................................................................................................................. 5-8

5.3.2.1 Overview .........................................................................................................................................................................................................5-8

5.3.3 Enlargement/Reduction.............................................................................................................................................................. 5-11

5.3.3.1 Magnifications in Main Scanning Direction .................................................................................................................................................5-11

5.3.3.2 Magnification in Sub Scanning Direction.....................................................................................................................................................5-11

5.3.4 Detecting the Size of Originals .................................................................................................................................................. 5-12

5.3.4.1 Overview .......................................................................................................................................................................................................5-12

5.3.4.2 Control Details ..............................................................................................................................................................................................5-12

5.3.4.3 Detection Operation Overview .....................................................................................................................................................................5-14

5.3.5 Dirt Sensor Control .................................................................................................................................................................... 5-15

5.3.5.1 Overview .......................................................................................................................................................................................................5-15

5.3.5.2 White Board Dust Detection Control ............................................................................................................................................................5-17

5.3.6 Image Processing ....................................................................................................................................................................... 5-18

5.3.6.1 Overview .......................................................................................................................................................................................................5-18

5.3.6.2 CCD Drive ....................................................................................................................................................................................................5-18

5.3.6.3 Gain Correction and Offset Correction of CCD Output ...............................................................................................................................5-18

5.3.6.4 A/D Conversion of CCD Output...................................................................................................................................................................5-19

5.3.6.5 Shading Correction (overview) .....................................................................................................................................................................5-19

5.3.6.6 Shading Adjustment ......................................................................................................................................................................................5-19

5.3.6.7 Shading Correction........................................................................................................................................................................................5-19

5.4 Parts Replacement Procedure.......................................................................................................................................5-20

5.4.1 CCD Unit ................................................................................................................................................................................... 5-20

5.4.1.1 Removing the CCD Unit ...............................................................................................................................................................................5-20

5.4.1.2 When Replacing the CCD Unit.....................................................................................................................................................................5-21

5.4.2 CCD Cover Unit ........................................................................................................................................................................ 5-21

5.4.2.1 Removing the CCD Cover Unit ....................................................................................................................................................................5-21

5.4.3 Copyboard glass......................................................................................................................................................................... 5-21

5.4.3.1 Removing the Copyboard Glass....................................................................................................................................................................5-21

5.4.3.2 When Replacing the Copyboard Glass .........................................................................................................................................................5-22

5.4.3.3 Removing the ADF Reading Glass ...............................................................................................................................................................5-23

5.4.3.4 When Replacing the ADF Reading Glass .....................................................................................................................................................5-23

5.4.4 Reader Controller PCB .............................................................................................................................................................. 5-24

5.4.4.1 Points to Note Before Replacing the Reader Controller PCB.......................................................................................................................5-24

5.4.4.2 Removing the Reader Controller PCB..........................................................................................................................................................5-24

5.4.4.3 After Replacing the Reader Controller PCB.................................................................................................................................................5-24

5.4.5 LED Driver PCB........................................................................................................................................................................ 5-25

5.4.5.1 Removing the LED Driver PCB ...................................................................................................................................................................5-25

5.4.6 Scanner Motor............................................................................................................................................................................ 5-25

5.4.6.1 Removing the Scanner Motor .......................................................................................................................................................................5-25

5.4.7 Copyboard Cover Open/Close Sensor ....................................................................................................................................... 5-25

Contents

Table of Contents