Canon BJ-W9000, Service Manual

Page: 193 / 455

b) Carriage controller GA (IC816)
BJ print head controller
The BJ print head controller sends image data (print signals) in the format of serial
data to each of the nozzle arrays of the BJ print heads. Also sends the nozzle block
selection signal to the BJ print heads.
Heat enable signal control
The carriage controller GA controls the duration of the voltage-supply of the heat
enable signal in the form of pulse width. Over this duration of time, the voltage is
applied to the nozzle heat board of the nozzle array on the BJ print head.
1200dpi timing generation
The carriage controller GA generates 1200dpi timing information that is created by
dividing the 300dpi timing of linear scale into quarters.
Dot counting
Provides the capability to count the ink-ejecting dots (normally operating nozzles)
of each nozzle array. This information is used for controlling the heat enable signal
and the maintenance jet operation.
Maintenance jet activation
Generates the heat pulse used for the maintenance jet operation.
Linear scale counting
Reads the linear scale when the carriage is travelling and generates the 1200dpi
timing.
Clock dividing
Generates the 16MHz clock information to drive the CPU from the 32MHz external
clock.
c) D/A converter (IC813)
The D/A converter is used to retrieve the detected value by the photosensor for print
position detection.
d) ASIC (IC823 and IC824)
Monitors the internal temperature, the head rank, and the head temperature.
e) LED (LED801)
This LED flashes red when the CPU on the carriage controller operates correctly.
f) LED (LED802)
This LED turns green when +10.3V for driving the BJ print heads is being supplied
to the carriage controller.
g) LED (LED803)
This LED turns green when +5V is being supplied to the carriage controller for the
operation of the controller's logic.
4-55
Part 4: Technical Reference BJ-W9000