Canon iR7086, Service Manual

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Chapter 5
5-12
to the tube axis, while the inner side is coated with fluorescent material. When high-frequency high voltage is applied to the electrodes, the gas inside the tube starts
to discharge, thus illuminating the fluorescent material.
F-5-22
5.3.3.4 Controlling the Activation
0010-7895
iR7105 / iR7095 / iR7086
The machine turns on or off the scanning lamp using the drive signal (XE_ON) from the CPU on the reader controller PCB. In response to the signal, the inverter
PCB generates high-frequency high voltage in the activation control circuit using the drive voltage (+24 V) supplied by the reader controller PCB, thus turning on
the xenon lamp.
5.3.4 Detecting the Size of Originals
5.3.4.1 Overview
0010-7897
iR7105 / iR7095 / iR7086
The machine identifies the size of an original with reference to the combination of measurements taken of the light reflected at specific points of the CCD and the
output of a reflection type sensor. It takes measurements at 2 points for individual sizes to ensure correct identification even in the event that the original is displaced
while the ADF is being closed.
- for main scanning direction, by the CCD (for AB, 8 points; for inch-configuration, 6 points)
- for sub scanning direction, by a reflection type photosensor (for AB-configuration, 1 point; for inch-configuration, 1 point)
The machine identifies the size of an original as follows:
1) External Light (main scanning direction only)
While keeping the scanning lamp off, the machine measures the CCD level at individual points of measurement in main scanning direction.
2) Sensor Output Level
The machine turns on the scanning lamp, and measures the CCD level at individual points of measurement in main scanning direction. Also, the machine turns
on the LED of the reflection type photosensor in sub scanning direction to measure the sensor output. It uses the combination of the measurement and the output
to identify the size of the original in question.
5.3.4.2 Points of Measurement Used for Original Size Identification
0010-7898
iR7105 / iR7095 / iR7086
For main scanning direction, the machine moves the No. 1 mirror base to the point of CCD original detection to measure the CCD level at individual points of
measurement. For sub scanning direction, the machine uses the outputs of original sensors 1 and 3.
F-5-23
1. Checking the Presence/Absence of an Original at 2 Points (individual points of detection)
For main scanning direction, the machine identifies the presence/absence of an original with reference to the CCD output at 2 points (nearest).
Fluorescent
material
Electrode
Opening
Electrode
Electrode Electrode
Glass tube
Point of original
detection 3
Point of original
detection 4
Point of original
detection 1
Print of original
detection 2
B5
B6
A5
A4
B5R
A4R
B4
A3
CCD original detection position
Point of original
detection 2
Point of original
detection 1
Point of original
detection 3
LTRR STMT
LTR
LGL
279.4×431.8mm
(11"×17")
CCD original detection position
Original
sensor 3
AB-Configuration Inch-configuration
STMTR
Original
sensor 1