Print Drive; Printing Drive Control - Canon BJC-55 Service Manual

BJC-50

1.4 Print Drive

The printer outputs control signals from the ASIC's printer controller to the BJ head to
eject ink from the BJ head for printing.
The control signals consist of the print control signal for ejecting ink from the head's
nozzles and the temperature control signal for adjusting the head's temperature so that
the amount of ink ejected is uniform.
To archive optimum printing, both these control signals are optimized by the printer
controller and sent from the carriage ribbon cable's signal contacts to the BJ head.
The drive frequency varies depending on the printing mode and BJ cartridge type.

1.4.1 Printing drive control

a) Black BJ cartridge drive control
The black BJ cartridge drive control is executed by dividing the head's 128 nozzles
into 8 blocks (16 nozzles each). These blocks are further divided into odd and even
blocks (8 nozzles each). The odd blocks eject ink simultaneously and the even
blocks do so as well. The control signals for the former are the block enable 0, 1,
and 2 signals (BENB 0, 1, 2) and for the latter the signals are the even/odd enable
signals (Even/Odd ENB). The heat enable A and D (HENB A, D), which are the
heater drive control signals for ejecting the ink, comprise of a prepulse and main
pulse. To constantly archive optimum ink ejection, the internal conditions such as
the head's rank, printer temperature, and head temperature are monitored and the
heater drive pulse width is varied before the pulse is output. Furthermore, the print
drive signal from the printer controller is transferred to the BJ head's shift resistor
according to the HLATCH timing. The printing drive signal (HDATA) is latched and
when the print control and heater drive control signals are output together, the
heater for the applicable nozzles is driven and the ink is ejected.
b) Color BJ cartridge (Large/Small Drop) drive control
The two-size droplet type color BJ cartridge has a print head with 136 nozzles and
each nozzle has two heaters, one infront of the other, that regulate the ejection of
large and small ink droplets. The 136 nozzles are divided into 8 functional blocks,
each block consisting of 16 nozzles. Ink is ejected consecutively from each block.
The order and selection of nozzles to be used are controlled by BLOCK ENABLE
signals (BENB 0,1,2) and the EVEN/ODD ENABLE signal (Even/Odd ENB). HEAT
ENABLE signals (HENB A,B,C,D) control the heater boards.
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Figure 4-3 Print Sequence (Black BJ Cartridge in HQ Mode)
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BE1 to BE 8 : Block Enable 1 to 8
E : Even Enable
O : Odd Enable
A : Heat Enable 0
B : Heat Enable 1
4-5
Part 4: Technical Reference
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