Engine Controller; Engine Controller Components - Canon WS8400 Service Manual

Table of Contents

This regulator IC generates the ASIC internal driving and DDR-SDRAM power supply (2.5V).

g) 1.25V regulator IC (IC4)

This regulator IC generates the termination power supply and reference power supply (1.25V).

2.4.3 Engine Controller

2.4.3.1 Engine controller components

a) CPU (IC1)

The CPU, with a 32-bit internal bus, operates in synchronization with the 132-MHz internal clock that is generated from a 66-MHz external clock.

The CPU is used 8-MB SDRAM (IC2), and 32-KB EEPROM (IC28). The CPU performs parameter control and has the following functions.

Timer function

This function is used for the cleaning functions.

The internal RTC and lithium battery allow the timer to operate even when the AC power supply is off for performing the cleaning function.

EEPROM control function

In addition to the EEPROM with on-board, it controls the six color independent ink tank EEPROM, maintenance cartridge EEPROM, and head EEPROM.

Ink tank level detection

This function detects the remaining ink level for each color based on the signals from the electrodes mounted on the hollow needle.

b) ASIC (IC4)

The ASIC, with a 32-bit internal bus, operates in synchronization with the 100-MHz internal clock that is generated from a 50-MHz external clock.

It uses four 32MB SDRAMs and two 8MB SDRAMs having the following functions:

System controller communication control

This function controls communication with the system controller.

Image data reception

Receives image data from the system controller, stores in SDRAM (IC15, IC16), and then converts to image data and stores in SDRAM (IC11, IC12, IC13,

IC14).

Image data generation/output

This function generates the image data for printing each color from the image data received from the system controller and mask pattern corresponding to

the print mode in the SDRAM (IC11, IC12, IC13, IC14) and stores it in SDRAM (IC15, IC16).

This function also controls the output of the generated image data to the carriage relay PCB.

Heat enable signal control

This functions uses the pulse width to perform variable control of the time that the heat enable signal is applied to the nozzle heater board for each nozzle

array in the printhead.

Linear scale count

This function reads the linear scale during carriage driving and generates the 150dpi timing signal.

2400-dpi timing generation

This function divides the linear scale 150-dpi timing into sixteen equal parts to generate the 2400-dpi timing signal.

Dot count

This function counts the discharge dots used as information for the heat enable signal function, maintenance jet control, cleaning function, and remaining

ink level for each nozzle array.

PWM control

This function performs driving control of the carriage motor, and suction fan and temperature control of the printhead based on the control signals from

the CPU.

Feed motor control

IC13

IC16

IC15

IC29

IC27

IC14

IC12

IC11

IC2

IC3