Canon BJC-55 Service Bulletin page 116

Part 4: Technical Reference
The HEAT ENABLE signals control the ejection of small and large ink droplets as
follows:
For each color, (Y, M and C), HENB B and A signals drive the front and back nozzle
heaters respectively. For black, HENB C and D signals drive the front and back
nozzle heaters respectively.
The HEAT ENABLE signal consists of the pre-pulse and the main pulse that optimize
ink ejection by constantly monitoring the head rank, the printer inner temperature
and head temperature. The ink is ejected by varying the HEAT ENABLE pulse
width.
HLATCH
HDATA
HCLOCK
Odd ENB
Even ENB
B ENB 0
B ENB 1
B ENB 2
H ENB A, B, C, D
Odd ENB
Even ENB
B ENB 0
B ENB 1
B ENB 2
H ENB A, B, C, D
Odd ENB
Even ENB
B ENB 0
B ENB 1
B ENB 2
H ENB A, D
H ENB B, C
When using a black BJ cartridge, HENEB A and D are drive signals. When using the color BJ
cartridge, HENEB A and B drive yellow, magenta and cyan, and HENEB C and D drive black.
HQ 164µs (6.43kHz)
720dpi/smoothing 164µs (6.43kHz*)
HS 92µs (7.82kHz)
128 or 136
1
0 2 3 4
1(0) 0(1) 1(0) 0(1)
1(0) 0(1)
1(0) 0(1)
1 Block
1(0) 0(1) 1(0) 0(1) 1(0) 0(1) 1(0)
1(0) 0(1) 1(0) 0(1)
1(0) 0(1)
1 Block
1 Block
Figure 4-4 Print Signals
Data transmission to shift resistor
Head Drive in HQ Mode (Divided into 16)
0(1)
Head Drive in HS Mode (Divided into 8)
Variable Pulse
Width
Head Drive in 720dpi (Divided into 8)
Large and small dot printing
4-6
BJC-50
Pre-Pulse
Main Pulse