Canon iR C2880 series, Руководство по обслуживанию

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Chapter 5
5-10
5.3.4 Controlling the Scanning Lamp
5.3.4.1 Scanning Lamp
0013-8584
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The machine's scanning lamp is a xenon lamp, in which xenon gas is sealed inside a tube. Along the glass tube are 2 electrodes, while the inside the glass tube is
coated with phosphorous material. When a high-frequency voltage is applied to the electrodes, electrons occur within the gas, thus causing the phosphorous material
to emit light.
F-5-15
5.3.4.2 Overview
0013-8586
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The scanning lamp is controlled for the following, and is composed of the items indicated:
- activation/de-activation
- error detection
F-5-16
5.3.4.3 Activation Control
0013-8587
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The scanning lamp is turned on/off using the drive signal (LAMP_ON) generated by the CPU of the reader controller PCB. In response to the signal, the inverter
PCB uses the drive voltage (+16 V) from the reader controller PCB to generate high-frequency voltage in the activation control circuit to turn on the xenon lamp.
5.3.4.4 Error Detection
0013-8588
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
An error in the intensity of the lamp is checked against the presence/absence of a fault when the lamp is initially tuned on (e.g., at time of shading correction).
E225 (CIS intensity error)
- fault in the inverter PCB
- fault in the reader controller PCB
- fault in the contact image sensor (CIS)
- fault in the flexible cable (poor contact)
5.3.5 Detecting the Size of Originals
5.3.5.1 Overview
0013-8589
/ / / / iR C3380i / iR C3380 / iR C2880i / iR C2880
The machine identifies the size of an original based on the measurements it takes of the light reflected by the original at specific points of the CCD (inside the CIS)
and the output of the reflection sensor.
- main scanning direction: CCD (4 points for AB; 3 points for Inch)
- sub scanning direction: reflection photosensor (1 point for AB; 1 point for Inch)
1) External Light Search (main scanning direction only)
While keeping the scanning lamp on, the machine measures the level of light at specific points of the CCD for main scanning direction.
2) Detecting the Sensor Output Level
The machine turns on the scanning lamp, and measures the CCD levels at individual points of detection in main scanning direction.
The machine also turns on the reflection photosensor and measures its output for sub scanning direction.
The machine identifies the size of the original based on the resulting combination of the measurement and the output.
Fluorescent
medium
Electrode
Opening
Electrode
Electrode Electrode
Glass tube
1
2
3
3
2
1
1
2
3
1
2
3
4
Inverter PCB
Activation
control circuit
Reader controller PCB
CPU
GND
LANP_ON
14.5V
J5015
J5018
J512
Xenon tube
CIS