Epson DLQ-3000 Service Manual page 57

Bi-d Adjustment Function >
The bidirectional printing adjustment is used to align dots vertically for bi-directional printing.
This is accomplished by delaying the print timing pulse for a line on which the carriage moves
from the 136th column to the Ist, using the print timing pulse when the carriage moves from the 1st
to 136th column as a reference. Since the print timing pulse vanes according to the carriage speed,
the adjustment should be implemented for each speed mode. For this printer, the adjustment can
be made for the 4fold and the default speed using 2-2 phase excitation (fast) or 1-2 phase excitation
(slow) respectively.
The print timing delay time is set and adjusted by the software.
Figure 2-18 shows a block diagram of the carriage motor controller/driver circuit.
Interlock Function>
The cover open switch is serially connected to the common (VPA) of Carnage motor. When the
PRINTER COVER is open, the common line is closed for safety.
CPU(IC1O)
CR A
CR-A
CR B
CR-B
GA(IC11)
T
Figure 2-18. Carriage Motor Drive Circuit Diagram
DRIVE IC
(I N-B
GP
FA
P
P FB
T
c l )
A
- A
GP
Operating Principles
CR COM
CR A
C R - A
CR B
C R - B
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