Canon iR5055 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............................................................................................................................................. 5-2
5.1.4 Reader Controller PCB ................................................................................................................................................................ 5-3
5.2 Basic Sequence ..............................................................................................................................................................5-4
5.2.1 Basic Sequence of Operations ..................................................................................................................................................... 5-4
5.2.2 Basic Sequence of Operation in Response to a Press on the Start Key ....................................................................................... 5-5
5.3 Various Control..............................................................................................................................................................5-5
5.3.1 Controlling the Scanner Drive System ........................................................................................................................................ 5-5
5.3.1.1 Overview .........................................................................................................................................................................................................5-5
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................................................................................................................................................................................................5-8
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..................................................................................................................................................................................5-10
5.3.5 Dirt Sensor Control .................................................................................................................................................................... 5-12
5.3.5.1 Dust Detection in Stream Reading Mode......................................................................................................................................................5-12
5.3.5.2 White Plate Dust Detection Control..............................................................................................................................................................5-13
5.3.6 Image Processing ....................................................................................................................................................................... 5-14
5.3.6.1 Overview .......................................................................................................................................................................................................5-14
5.3.6.2 CCD Drive ....................................................................................................................................................................................................5-15
5.3.6.3 CCD Output Gain Correction, Offset Correction .........................................................................................................................................5-15
5.3.6.4 CCD Output A/D Conversion .......................................................................................................................................................................5-15
5.3.6.5 Outline of Shading Correction ......................................................................................................................................................................5-15
5.3.6.6 Shading Adjustment ......................................................................................................................................................................................5-16
5.3.6.7 Shading Correction........................................................................................................................................................................................5-16
5.4 Parts Replacement Procedure.......................................................................................................................................5-17
5.4.1 CCD Unit ................................................................................................................................................................................... 5-17
5.4.1.1 Before Removing the CCD Unit ...................................................................................................................................................................5-17
5.4.1.2 Removing the CCD Unit ...............................................................................................................................................................................5-17
5.4.1.3 When Replacing the CCD Unit.....................................................................................................................................................................5-17
5.4.2 Copyboard glass......................................................................................................................................................................... 5-18
5.4.2.1 Removing the Copyboard Glass....................................................................................................................................................................5-18
5.4.2.2 When Replacing the Copyboard Glass .........................................................................................................................................................5-18
5.4.3 Scanning Lamp .......................................................................................................................................................................... 5-18
5.4.3.1 Before Removing the Scanning Lamp ..........................................................................................................................................................5-18
5.4.3.2 Removing the Scanning Lamp ......................................................................................................................................................................5-18
5.4.3.3 When Replacing the Scanning Lamp ............................................................................................................................................................5-19
5.4.4 Reader Controller PCB .............................................................................................................................................................. 5-19
5.4.4.1 Before Removing the Reader Controller PCB ..............................................................................................................................................5-19
5.4.4.2 Removing the Reader Controller PCB..........................................................................................................................................................5-19
5.4.4.3 After Replacing the Reader Controller PCB.................................................................................................................................................5-20
5.4.5 Interface PCB............................................................................................................................................................................. 5-20
5.4.5.1 Before Removing the Interface PCB.............................................................................................................................................................5-20
5.4.5.2 Removing the Interface PCB ........................................................................................................................................................................5-20
Contents