Canon BJC-55 Series, Service Bulletin

Page: 150 / 249

4.3.2 Power supply section structure
a) Input power supply
The voltage input to the power supply section is 13.5 ± 0.5 VDC. It is supplied by
two sources: the Universal adapter and the lithium ion battery.
When the DC plug is inserted into the power connector, 13 VDC is supplied to the
power control section on the control board.
b) Vcc1 output
The Vcc1 is +5VDC output produced by the DC/DC converter. Vcc1 is supplied to
operate the reset IC, ASIC, ROM, RAM, timer IC, EEPROM, and as a pull-up power
supply for the
POWER button. It is always supplied, even after the power switch is
OFF.
c) Vcc2 output
The Vcc2 (+5VDC) output controlled by the ASIC is used to operate the IC in the
print head. The ASIC outputs a signal that turns Vcc2 output off to stop it when the
BJ cartridge is replaced, the ink cartridge is replaced, or the printer is turned OFF
with the
POWER button.
d) Vcc3 output
The Vcc3 (+5VDC) output controlled by the ASIC is supplied to operate the interface,
paper sensor, and HP sensor. When the
POWER button is turned OFF with the
POWER button, the ASIC stops the Vcc3 output.
e) Vpp output
The DC input voltage supplied from the Universal adapter or lithium ion battery
becomes Vpp output to drive the carriage motor driver and the paper feed motor
driver.
f) VH output
The VH (24.12 VDC ± 0.35 VDC) output generated by the DC/DC converter is
supplied to the print head and the paper feed driver. This is monitored by the ASIC.
The VH output voltage is supplied to the subheater temperature adjustment driver
transistor and the nozzle heater temperature adjustment drivers transistor in the BJ
cartridge and the paper feed motor driver. The DCLEV, which is generated by
dividing the VH output using a DC/DC converter, is fed back to the ASIC and the
ASIC monitors the VH output voltage to be kept at approx. 24.12 VDC.
Part 4: Technical Reference
BJC-50
4-40