Epson SEIJ98006 Service Manual page 70

EPSON Stylus Color 900
Unlike the previous EPSON ink jet printers, the number pf the phase
excitation input ports in the motor drive IC of this printer has increased
to 8. The previous micro step system used total of 4 phase excitation
input signals for both Phase A and Phase B. (Stylus COLOR, Stylus
PRO series, and Stylus PRO XL series are exceptional, since they
transfer 4-bit serial data from ASIC to the motor driver.) This is because
the micro stepping was controlled by the software only. On the other
hand, LB1847 enables 4W1-2 phase excitation using the hardware and
is equipped with the necessary number of input ports (8 ports) for
current setting signals. Among 8 input ports, 4 are allocated to each
phase, A and B. Therefore, 16 types of current setting data can be
constantly sent to the driver IC. The LB1847 controls the micro stepping
system by exciting the corresponding phase based on the combinations
of the setting signals sent from the ASIC.
Table 2-17 shows the excitation modes used for the PF motor and their
usage.
Table 2-17. PF Motor Excitation Mode and Usage
Excitation phase Usage
2-2 phase drive Not used
Fast feed 1
1-2 phase drive Fast feed 2
Special fast feed
W1-2 phase drive Not used
2W1-2 phase drive Middle-speed feed
Normal feed
4W1-2 phase drive Micro adjust feed
Slow feed
Operating Principles
Minimum step
1/720"(0.035 mm)
1/1440"(0.018 mm)
1/2880"(0.009 mm)
1/5760"(0.004 mm)
1/11520"(0.004 mm)
Electrical Circuit Operation Principles
Revision C
70