Canon iR2020 Series Service Manual page 9

3.4 Flow of Image Data ........................................................................................................................................ 3- 5
3.4.1 Flow of Image Data According to Copy Functions ............................................................................. 3- 5
3.4.2 Flow of Image Data for the SEND Function ........................................................................................ 3- 6
3.4.3 Flow of Image Data for the Fax Transmission .................................................................................... 3- 6
3.4.4 Flow of Image Data for the Fax Reception Function.......................................................................... 3- 7
3.4.5 Flow of Image Data for the PDL Function............................................................................................ 3- 7
3.5 Parts Replacement Procedure ..................................................................................................................... 3- 9
3.5.1 Main Controller PCB ................................................................................................................................ 3- 9
3.5.1.1 Removing the Rear Cover............................................................................................................... 3- 9
3.5.1.2 Removing the Left Cover (Rear) .................................................................................................... 3- 9
3.5.1.3 Removing the RAM Cover............................................................................................................... 3- 9
3.5.1.4 Removing the SDRAM..................................................................................................................... 3- 9
3.5.1.5 Removing the LAN Cover................................................................................................................ 3- 9
3.5.1.6 Removing the IP Cover.................................................................................................................... 3- 9
3.5.1.7 Removing the IP Cover.................................................................................................................. 3- 10
3.5.1.8 Removing the image processor PCB .......................................................................................... 3- 11
3.5.1.9 Procedure after Replacing the Image Processor PCB ............................................................ 3- 11
3.5.2 SDRAM .................................................................................................................................................... 3- 11
3.5.2.1 Removing the Rear Cover............................................................................................................. 3- 11
3.5.2.2 Removing the RAM Cover............................................................................................................. 3- 11
3.5.2.3 Removing the SDRAM................................................................................................................... 3- 12
Chapter 4 Original Exposure System
4.1 Construction..................................................................................................................................................... 4- 1
4.1.1 Specifications, Control Methods, and Functions ................................................................................ 4- 1
4.1.2 Major Components .................................................................................................................................. 4- 1
4.1.3 Control System Configuration................................................................................................................ 4- 2
4.1.4 Reader Controller PCB ........................................................................................................................... 4- 2
4.2 Basic Sequence .............................................................................................................................................. 4- 3
4.2.1 Basic Sequence at Power-on ................................................................................................................ 4- 3
4.2.2 Basic Sequence after Depression of Start Key (Book mode, One Sheet of original)................... 4- 4
4.2.3 Basic Sequence after Depression of Start Key (ADF Mode, One Sheet of Original) ................... 4- 4
4.3 Various Control ............................................................................................................................................... 4- 5
4.3.1 Controlling the Scanner Drive System .................................................................................................. 4- 5
4.3.1.1 Outline ................................................................................................................................................ 4- 5
4.3.1.2 Reader Motor Control....................................................................................................................... 4- 6
4.3.2 Contact Image Sensor (CIS) .................................................................................................................. 4- 6
4.3.2.1 Outline ................................................................................................................................................ 4- 6
4.3.2.2 Analog Control Performed by the CIS ........................................................................................... 4- 7
4.3.3 Enlargement/Reduction........................................................................................................................... 4- 8
4.3.3.1 Magnification Change in Vertical Scan Direction......................................................................... 4- 8
4.3.3.2 Magnification Change in Horizontal Scan Direction .................................................................... 4- 8
4.3.4 Detecting the Size of Originals............................................................................................................... 4- 8
4.3.4.1 Outline ................................................................................................................................................ 4- 8
4.3.4.2 Outline of Original Size Detection .................................................................................................. 4- 9
4.3.5 Dirt Sensor Control................................................................................................................................. 4- 10
4.3.5.1 Outline .............................................................................................................................................. 4- 10
4.3.6 Image Processing................................................................................................................................... 4- 11
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