Service manual

Part 4: Technical Reference
BJC-4300
1.4 Print Drive
To eject ink from the head for printing, the printer outputs control signals from the
printer controller to the BJ head.
The control signals consist of the drive 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 achieve 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 1, 2,
and 3 signals (BENB 1, 2, 3) and for the latter the signals are the even/odd enable
signals (Even/odd ENB).
The heat enable 0 and 1 &IENB 0, 1). which are the heater drive control signals for
ejecting the ink. comprise of a pre-pulse and main pulse. To constantly achieve
optinmm 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 drive control
The color BJ cartridge head’s nozzle configuration differs from that of the black BJ
cartridge. Vhe black has 64 nozzles while the color has 24 nozzles each for Y, M,
and C.) Therefore, the number of nozzles in each control block is different from that
of the black BJ cartridge. Furthermore, since the heaters are driven simultaneously for
each color, the heater drive control signals used are the heat enable [HENB) 0, 1, 2. and 3
signals. All other operations are the same as for the black BJ cartridge.
For heat enable, the HENB 0, 1, and 2 signals drive the nozzle heaters for Y, M. and
C. The HENB 3 signal drives the nozzle heater for black ink.
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