Canon iR4570 Series Service Manual page 10

Contents
5.2.3Basic Sequence of Operation in Response to a Press on the Start Key (ADF mode; 1 original )............... 5- 8
5.3 Various Control ............................................................................................................................................... 5- 10
5.3.1 Controlling the Scanner Drive System...................................................................................................... 5- 10
5.3.1.1 Outline ............................................................................................................................................... 5- 10
5.3.1.2 Controlling the Reader Motor............................................................................................................ 5- 10
5.3.2 Contact Image Sensor (CIS)...................................................................................................................... 5- 12
5.3.2.1 Outline ............................................................................................................................................... 5- 12
5.3.2.2 Analog Control Inside the Contact Image Sensor ............................................................................. 5- 13
5.3.3 Enlargement/Reduction ............................................................................................................................. 5- 14
5.3.3.1 Changing the Magnification in Main Scanning Direction................................................................. 5- 14
5.3.3.2 Varying the Magnification in Sub Scanning Direction ..................................................................... 5- 14
5.3.4 Detecting the Size of Originals ................................................................................................................. 5- 16
5.3.4.1 Outline ............................................................................................................................................... 5- 16
5.3.4.2 Outline of Size Identification............................................................................................................. 5- 17
5.3.5 Dirt Sensor Control ................................................................................................................................... 5- 19
5.3.5.1 Outline ............................................................................................................................................... 5- 19
5.3.6 Image Processing....................................................................................................................................... 5- 22
5.3.6.1 Outline ............................................................................................................................................... 5- 22
5.3.6.2 CCD Drive ......................................................................................................................................... 5- 23
5.3.6.3 Gain Correction and Offset Correction of the CCD Output .............................................................. 5- 23
5.3.6.4 A/D Conversion of the CCD Output.................................................................................................. 5- 24
5.3.6.5 Shading Correction (outline) ............................................................................................................. 5- 24
5.3.6.6 Shading Adjustment........................................................................................................................... 5- 24
5.3.6.7 Shading Correction ............................................................................................................................ 5- 24
5.4 Parts Replacement Procedure .......................................................................................................................... 5- 26
5.4.1 Copyboard glass ........................................................................................................................................ 5- 26
5.4.1.1 Removing the Copyboard Glass ........................................................................................................ 5- 26
5.4.1.2 Removing the ADF Reading Glass.................................................................................................... 5- 26
5.4.2 Reader Controller PCB.............................................................................................................................. 5- 27
5.4.2.1 Before Replacing the Reader Controller PCB ................................................................................... 5- 27
5.4.2.2 Removing the Reader Rear Cover ..................................................................................................... 5- 27
5.4.2.3 Removing the rear cover of the machine ........................................................................................... 5- 27
5.4.2.4 Removing the flexible cable cover .................................................................................................... 5- 28
5.4.2.5 Removing the Copyboard Glass ........................................................................................................ 5- 28
5.4.2.6 Removing the Reader Controller PCB............................................................................................... 5- 29
5.4.2.7 After Replacing the Reader Controller PCB or After Initializing the RAM ..................................... 5- 31
5.4.3 Scanner Motor ........................................................................................................................................... 5- 32
5.4.3.1 Removing the Reader Rear Cover ..................................................................................................... 5- 32
5.4.3.2 Removing the Scanner Motor ............................................................................................................ 5- 32
5.4.4 Contact sensor ........................................................................................................................................... 5- 33
5.4.4.1 Removing the Reader Front Cover .................................................................................................... 5- 33
5.4.4.2 Removing the Reader Rear Cover ..................................................................................................... 5- 33
5.4.4.3 Removing the Copyboard Glass ........................................................................................................ 5- 34
5.4.4.4 Removing the Contact Image Sensor (CIS)....................................................................................... 5- 35
5.4.4.5 After Replacement of the CIS............................................................................................................ 5- 36
5.4.5 Copyboard Cover Open/Close Sensor....................................................................................................... 5- 36
5.4.5.1 Removing the Reader Rear Cover ..................................................................................................... 5- 36
5.4.5.2 Removing the Copyboard Cover Open/Closed Sensor (front/rear)................................................... 5- 37
5.4.6 Contact Sensor HP Sensor......................................................................................................................... 5- 37
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