Canon iPF8400S Series, Service Manual

Page: 95 / 312

Chapter 2
2-29
2.4.2 Main Controller
2.4.2.1 Main controller PCB components
0029-0084
F-2-25
a) ASIC (IC1/IC2)
The ASIC(IC1/IC2) with a 32/16-bit internal bus is driven in sync with the 330/66 MHz external clock. It supports the following functions:
Image processing unit
This unit converts the RGB multi-value image data or CMYK multi-value data received from the host computer through the interface connector to the binary image
data for the ink colors used.
DMA controller
This controller control DMA transfer of the data transferred through the input interfaces such as the USB and expansion card slot as well as DMA transfer of the
data stored in the DIMM.
Image data generation/output function
This function generates image data for color printing from the received image data and the mask pattern (corresponding to print mode) stored in the FLASH ROM,
and stored the generated image data in DIMM. It also outputs the generated image data to the carriage relay PCB.
Interrupt controller
This controller receives and processes internal interrupts and external interrupts from the USB, image processing unit, and expansion card slot.
Timer function
Even when the printer is turned off, the timer function is held on using the RTC(IC803) and lithium battery(BAT801) to assist the cleaning function.
When the power cord is plugged to the outlet, power is supplied to the RTC and therefore the lithium battery power is not consumed.
Heat Enable signal control function
This function uses the pulse width to perform variable control of the time of application of the Heat Enable signal to the nozzle heater board for each printhead
nozzle array.
Linear scale count function
This function reads the linear scale when the carriage moves, thus generating the ink discharge timing. It also counts the linear scale timing cycle using the reference
clock to measure the carriage moving speed.
Dot count function
This function controls the discharge dots used as the information for Heat Enable signal control, maintenance jet control, cleaning control, and remaining ink level
for each nozzle array.
Operation panel control function
This function controls serial communication with the operation panel.
PWM control function
This function controls driving of the suction fan and mist fan as well as the temperature of the printhead.
Remaining ink level detection function
This function detects the remaining level of each color of ink based on the signal received from the hollow needle mounted in the ink tank unit.
LED control function
This function controls the LEDs on the ink tank unit.
I/O port function
This function controls input signals from sensors.
Power ON/OFF control function
This function controls turning on/off of the drive power (32V and 5.1V) supplied from the power supply PCB.
Head DI sensor read control function
This function controls read operation by the head DI sensor.
Multi sensor control function
This function controls the LED, adjusts the gain, and controls obtainment of the reading for the multi sensor.
IC2902
IC 8 0 3
IC2 8 02 IC2 8 02
IC 8 02
IC2900 IC2900
IC70 3
IC1201
IC701
IC601
IC1
IC2
IC 3 100
BAT 8 01
IC602
IC60 3
IC604
IC2700
J401