Document Exposure/Feeder System; Document Exposure System; Overview; Major Components - Canon imageCLASS MF4890dw Service Manual

2
Technical Overview > Document Exposure/Feeder System > Document Exposure System > Major Components

Document Exposure/Feeder System

Document Exposure System

■ Overview

item
document exposure LED
document scan Book mode: scan by the shift of the contact Book mode: scan by the
shift of the contact sensor (CS)
SADF/DADF: document stream reading by fixed contact sensor (CS)
scanning resolution 600 dpi (horizontal scanner) X 600 dpi (vertical scanner)
number of gradations 256 gradations
magnification 50% to 200%
horizontal: image processing by Main controller PCB
vertical: change of carriage shift speed, image processing by Main
controller PCB
lens rod lens array
CMOS sensor number of lines: 1 line
number of pixels: 5148 pixels as total pixels (5107 pixels as effective
pixels)
maximum document scanning width: 216 mm
CS drive control drive control by Reader motor
document size detection none
2 Technical Overview > Document Exposure/Feeder System > Document Exposure System > Major Components
function / method
T-2-2

■ Major Components

Followings are the major components for Document Exposure System.
• The contact sensor to scan document
• The Reader motor, the drive pulley, the drive belt, to shift the contact sensor
In image scanning control, the contact sensor is shifted by rotating the Reader motor based
on the drive signal from the SCNT PCB and scan the original on the copyboard glass. When
ADF is in use, image is scanned by feeding the originals by ADF instead of shifting the
contact sensor.
Reader motor
Drive pulley
2-6
Drive belt
Drive pulley
Contact sensor
F-2-5
2-6