Canon LASER CLASS 810 Service Manual page 83

3.1.3 Image Processor PCB
1.function
The image processor PCB has the following functions.
Control Panel Control Block
The control panel control block receives the state of control keys while sending/receiving data in serial communication with the control IC of the control panel PCB.
Also, it sends LED and LCD signals to the control panel PCB.
Image Processing Control Block
- It subjects the digital image data from the analog processor PCB to enlargement/reduction processing, smoothing, and other image processing, thereby con-
verting it to 600x600-dpi image signals (VD0, VD01*, VDO2, VDO2*).
- It converts the analog image data from fax communication into 600x600-dpi image signals (VD0, VD01*, VDO2, VDO2*).
- It uses a horizontal sync signal (BD0*) as a trigger to send image signals (VD0, VD01*, VDO2, VDO2*) to the laser unit.
Smoothing
The 600 x 600-dpi image data from the PC is converted into image data equivalent of 1200 x 600 dpi.
Sensor Detection
It detects the state of each sensor of the reader unit and the ADF.
ESS Control
It controls the ESS function used to reduce the power consumption while the machine isin standby state.
Memory Storage
Image data is stored in SDRAM, and is retained for about 1 hr even after the power is removed by the work of the super capacitor mounted on the modem PCB.
The system software and various data (e.g., user data, service data) are held by flash ROM.
Speaker Control (if equipped with fax functions.)
It turns on/off or control the volume of the error sound, key sound, and line monitor sound generated by the speaker.
MEMO:
The volume of the line monitor or the sound of the key sound or the error sound is adjusted in user mode.
2. Construction
The image processor comes in different ROM types/sizes and RAM sizes according to models.
The firmware stored in the flash ROM may be either SYSTEM or BOOT.
Using the service support tool, the following 2 types of firmware may be upgraded: SYSTEM and BOOT stored in the flash ROM and the firmware stored ion
SEND ROM.
3.1.4 DC Controller PCB
Fixing Heater Control Block
The fixing heater control block monitors the temperature reading of the thermistor to ensure that the temperature of the heater reaches a specific level. If an error
is detected in the temperature of the heater, it stops the power to the heater.
<with SEND functions>
Image processor PCB
SDRAM (256MB)
CPU
*1: LASER CLASS 830i is 16MB.
<w/o SEND functions, with network functions>
<w/o SEND functions, w/o network functions>
Image processor PCB
SDRAM (128MB)
CPU
F-3-3
Flash ROM (16MB)
SEND ROM(32MB)*1
Flash ROM (16MB)
Chapter 3
0016-7908
0016-7909
3-3