Canon iR6570 series Service Manual page 137

Contents
5.1 Construction ...................................................................................................................................................................5-1
5.1.1 Specifications, Controls, and Functions....................................................................................................................................... 5-1
5.1.2 Major Components....................................................................................................................................................................... 5-1
5.1.3 Construction of the Control System............................................................................................................................................. 5-3
5.1.4 Reader Controller PCB ................................................................................................................................................................ 5-3
5.2 Basic Sequence ..............................................................................................................................................................5-5
5.2.1 Basic Sequence of Operations ..................................................................................................................................................... 5-5
5.2.2 Basic Sequence of Operation in Response to a Press on the Start Key ....................................................................................... 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 Controlling the Scanner Motor........................................................................................................................................................................5-6
5.3.2 Enlargement/Reduction................................................................................................................................................................ 5-7
5.3.2.1 Changing the Magnification in Main Scanning Direction ..............................................................................................................................5-7
5.3.2.2 Changing the Magnification in Sub Scanning Direction ................................................................................................................................5-7
5.3.3 Controlling the Scanning Lamp ................................................................................................................................................... 5-8
5.3.3.1 Overview .........................................................................................................................................................................................................5-8
5.3.3.2 Scanning Lamp................................................................................................................................................................................................5-9
5.3.3.3 Controlling the Activation...............................................................................................................................................................................5-9
5.3.4 Detecting the Size of Originals .................................................................................................................................................... 5-9
5.3.4.1 Overview .........................................................................................................................................................................................................5-9
5.3.4.2 Points of Measurement Used for Original Size Identification ........................................................................................................................5-9
5.3.4.3 Overview of Operation..................................................................................................................................................................................5-11
5.3.5 Dirt Sensor Control .................................................................................................................................................................... 5-13
5.3.5.1 Dust Detection in Stream Reading Mode......................................................................................................................................................5-13
5.3.5.2 White Plate Dust Detection Control..............................................................................................................................................................5-14
5.3.6 Image Processing ....................................................................................................................................................................... 5-15
5.3.6.1 Overview .......................................................................................................................................................................................................5-15
5.3.6.2 CCD Drive ....................................................................................................................................................................................................5-16
5.3.6.3 CCD Output Gain Correction, Offset Correction .........................................................................................................................................5-17
5.3.6.4 CCD Output A/D Conversion .......................................................................................................................................................................5-17
5.3.6.5 Outline of Shading Correction ......................................................................................................................................................................5-17
5.3.6.6 Shading Adjustment ......................................................................................................................................................................................5-17
5.3.6.7 Shading Correction........................................................................................................................................................................................5-17
5.4 Parts Replacement Procedure.......................................................................................................................................5-19
5.4.1 CCD Unit ................................................................................................................................................................................... 5-19
5.4.1.1 Removing the Copyboard Glass....................................................................................................................................................................5-19
5.4.1.2 Removing the CCD Unit Cover ....................................................................................................................................................................5-19
5.4.1.3 Removing the Original Size Sensor Unit ......................................................................................................................................................5-19
5.4.1.4 Removing the CCD Unit ...............................................................................................................................................................................5-20
5.4.1.5 When Replacing the CCD Unit.....................................................................................................................................................................5-20
5.4.2 Copyboard glass......................................................................................................................................................................... 5-20
5.4.2.1 Removing Copyboard Glass .........................................................................................................................................................................5-20
5.4.2.2 When Replacing the Platen Board Glass ......................................................................................................................................................5-20
5.4.3 Scanning Lamp .......................................................................................................................................................................... 5-20
5.4.3.1 Removing the Copyboard Glass....................................................................................................................................................................5-20
5.4.3.2 Removing the Right Cover (upper)...............................................................................................................................................................5-21
5.4.3.3 Removing the Reader Right Cover ...............................................................................................................................................................5-21
5.4.3.4 Removing the Left Cover (upper) .................................................................................................................................................................5-21
5.4.3.5 Removing the Reader Left Cover .................................................................................................................................................................5-21
5.4.3.6 Removing the Reader Front Cover ...............................................................................................................................................................5-22
5.4.3.7 Removing the Reader Unit Rear Cover ........................................................................................................................................................5-22
5.4.3.8 Removing the CCD Unit Cover ....................................................................................................................................................................5-23
Contents