Epson LQ-2550 Technical Manual page 149

The CS motor is a 4-phase stepper motor, and the phases are controlled by MCU(3B) terminals A02
to D02. 2-2 phase switching is used for controlling this motor. Figure 2-95 shows the CS motor phase
switching timing.
(301
Color Ribbon Switching Control
When power is applied, a color home position seek is performed. This operation mechanically
determines the color home position by rotating the CS motor counterclockwise for 150 steps(120 steps
are used for actual movement.). (120 - 150 + n steps cannot be adjusted. See Figure 2-1 3.)
The ribbon color is switched in the sequence black ~ cyan ~ magenta ~ yellow for every 40 steps
starting from the color home position.
I
OFF
ON
C02
OFF
ON
I
B02
OFF
ON
I
OFF
Step
2
I
Rotation
c .C .W ~ C .W (Color ribbon B+C+M+Y)
Figure Motor Phase Switching Timing
2-95. CS
I I
3 4
2-103
REV.-A