Canon IMAGERUNNER 7095 PRINTER, Руководство по обслуживанию

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Chapter 5
5-12
5.3.3.3 Scanning Lamp
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The machine's scanning lamp is a xenon lamp consisting of a tube in which xenon gas is sealed. On the
inner side of the glass tube are 2 electrodes running parallel 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
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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 turn-
ing on the xenon lamp.
5.3.4 Detecting the Size of Originals
5.3.4.1 Overview
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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 meas-
urements 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
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For main scanning direction, the machine moves the No. 1 mirror base to the point of CCD original detec-
tion to measure the CCD level at individual points of measurement. For sub scanning direction, the ma-
chine uses the outputs of original sensors 1 and 3.
F-5-23
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