Canon imagePRESS C1 Service Manual - page 287
Chapter 5
5-8
PCB generates high-frequency high voltage using the activation control circuit from the drive voltage (+24V) supplied by the reader controller PCB, thus turning
on the scanning lamp.
2. Detection Error Activation
The machine detects a fault in the intensity of the lamp as an activation error caused by a fault in the intensity of the lamp at time of initial activation (shading
correction).
MEMO:
E225
- the reader controller PCB is faulty
- the inverter PCB is faulty
- the scanning lamp (xenon tube) is faulty
- CCD is faulty
- flexible cable has poor contact
F-5-15
5.3.3.2 Scanning Lamp
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imagePRESS C1 / Color Image Reader-H1 / imagePRESS C1+ (Printer) / imagePRESS C1+
The machine's scanning lamp is a xenon lamp, which uses xenon gas sealed inside. On the outside of the glass tube, 2 electrodes are arranged in parallel with the
tube; the inside of the tube, on the other hand, is coated with fluorescent material. When a high-frequency high voltage is applied to the electrodes, the gas inside
the tube starts to discharge, causing the fluorescent material to emit light.
F-5-16
5.3.3.3 Turning On and Off the Scanning Lamp
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imagePRESS C1 / Color Image Reader-H1 / imagePRESS C1+ (Printer) / imagePRESS C1+
The scanning lamp is turned on and off by the drive signal (LAMP_ON) generated by the CPU of the reader control PCB. When the signal is generated, 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 to turn on the
xenon lamp.
5.3.4 Detecting the Size of Originals
5.3.4.1 Identifying the Size of Originals
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imagePRESS C1 / Color Image Reader-H1 / imagePRESS C1+ (Printer) / imagePRESS C1+
The machine identifies the size of an original based on combinations of measurements taken of the light reflected by specific points (using a reflection type sensor
and CCD). In consideration of possible displacement of the original when the ADF is closed, the machine uses a 2-point CCD check.
- Main Scanning Direction:
by CCD (AB-configuration; 8-point measurement; inch-configuration, 6-point measurement)
- Sub Scanning Direction:
reflection type photo sensor (AB-configuration: 1-point measurement; inch-configuration: 1-point measurement)
Specifically, the following takes place:
1) External Light Search (main scanning direction only)
While keeping the scanning lamp off, the machine measures the level of the CCD at specific points in main scanning direction.
2) Sensor Output Level Detection
The machine turns on the scanning lamp, and measures the sensor output at specific points. It then checks combinations of these measurement to find the size
of the original.
5.3.4.2 Points of Measurement Used for Original Size Identification
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imagePRESS C1 / Color Image Reader-H1 / imagePRESS C1+ (Printer) / imagePRESS C1+
For main scanning direction, the machine moves the No. 1 mirror base to the following points in relation to the location of the original to measure the levels of the
CCD. For sub scanning direction, the machine checks the states of the sensors arranged as follows:
Inverter PCB
Xenon lamp
Activation
control circuit
J601 J206
Reader controller PCB
LA1
CPU
GND
GND
GND
GND
XE-ON
24V
24V
XSYNC
24V
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
fluorescent
medium
electode
opening
electode
electode
electode
glass tube