Canon imageRUNNER 2270 Service Manual page 165

Contents
Chapter 5 Original Exposure System
5.1 Construction............................................................................................................... 5-1
5.1.1 Specifications, Control Mechanisms, and Functions .......................................... 5-1
5.1.2 Major Components.............................................................................................. 5-3
5.1.3 Construction of the Control System.................................................................... 5-5
5.1.4 Reader Controller PCB ....................................................................................... 5-6
5.2 Basic Sequence .......................................................................................................... 5-8
5.2.1 Basic Sequence of Operation at Power-On......................................................... 5-8
5.2.2 Basic Sequence of Operation in Response to a Press on the Start Key (book mode;
1 original) ................................................................................................................. 5-9
5.2.3 Basic Sequence of Operation in Response to a Press on the Start Key (ADF mode;
1 original ) .............................................................................................................. 5-10
5.3 Various Control........................................................................................................ 5-11
5.3.1 Controlling the Scanner Drive System .............................................................. 5-11
5.3.2 Contact Image Sensor (CIS) ............................................................................. 5-13
5.3.3 Enlargement/Reduction ..................................................................................... 5-16
5.3.4 Detecting the Size of Originals ......................................................................... 5-17
5.3.5 Dirt Sensor Control ........................................................................................... 5-21
5.3.6 Image Processing ..............................................................................................5-26
5.4 Parts Replacement Procedure .................................................................................. 5-29
5.4.1 Copyboard glass ................................................................................................5-29
5.4.2 Reader Controller PCB .....................................................................................5-31
5.4.3 Scanner Motor ...................................................................................................5-37
5.4.4 Contact sensor ...................................................................................................5-38
5.4.5 Copyboard Cover Open/Close Sensor ..............................................................5-41
5.4.6 Contact Sensor HP Sensor ................................................................................5-41
5.4.7 Original Size Sensor ..........................................................................................5-42
5.4.8 Reader Heater (option) ......................................................................................5-44
Contents