Canon BJ-W9000, Service Manual

Page: 145 / 455

1.3.2 Print Drive Timing
Each BJ print head has three nozzle arrays (A, B and C) on it, all of which use three
types of signals: the data transfer clock (CLK), data latch pulse (LATCH), and block
enable (BE 0, 1, 2 and 3).
On the other hand, the even nozzle data (DATA AE, BE and CE), the odd nozzle data
(DATA AO, BO and CO),the heat enable signals (HE A, B and C) and the sub heat
enable signals (SHE A, B and C) are sent to a specific array as required in order to
control each array separately.
Printing operations are performed in a bi-directional fashion, namely in both forward
and reverse directions.
The encoder sensor installed on the carriage generates the detection signals (CR-
ENCA), which are created using the linear scale of 300dpi pitch, and the signals (CR-
ENCB) which are out of phase by 90 degrees (half of the pulse width) from the CR-
ENCA. By comparing the rises/amplitudes of CR-ENCA and CR-ENCB, the moving
direction of the carriage can be identified.
The BJ print heads are driven via the 1200dpi timing signals (XOL-STR) that are
created by spreading a single CR-ENCA (300dpi pitch) to four individual signals.
The execution of forward printing is based on the amplitudes of the detection signals
(CR-ENCA).
The reverse printing is executed based on the falls of the detection signals (CR-ENCA)
in the same manner as the forward printing, except that the transmission order of the
even and odd nozzle signals, and the heating order of the nozzles by the block enable
signals are performed in reverse order.
4-7
BJ-W9000 Part 4: Technical Reference
Figure 4-4 Example of Print Drive Timing (Nozzle Array A and Forward Printing)
300dpi
1200dpi
Linear scale
CR-ENCA
CR-ENCB
XCOL-STR
CLK
DATA AO
DATA AE
LATCH
BE(0-3)
HE A
SHE A
Data of block 0
Data of block 0
Data of block 2
Data of block 2
Data of block 4
Data of block 4
Block 0 Block 2 Block 10
Low active
Low active
Data of block 14
Block 12 Block 14
1200dpi
Data of block 12
Data of block 14 Data of block 12