Epson LQ-2550 Technical Manual page 147

PG Motor Phase Switching Timing
The PG motor is a 4-phase stepper motor, and the phases are controlled by MCU(3B) terminals AO1
to DO 1. 2-2 phase switching is used for this motor. Figure 2-92 shows the PG motor phase switching
timing.
(3B)
Relationship Between Platen Gap and Papar Thickness
The paper thickness value detected by the PT sensor is processed by the sub CPU(7B), which rotates
the PG motor to obtain the proper platen gap (see Section 2.1 .2.2).
During initialization after power is applied, the PG motor is driven to set the platen gap, starting from
the platen gap home position determined by the PG HP sensor ( 1.2 mm from the platen). The PG motor
increments or decrements the platen gap in steps of 0.0014 mm. Figure 2-93 shows the relationship
between paper thickness and platen gap.
If the control panel is set, a total of 10 steps of fine adjustment can be manually performed on the platen
gap value with 0.014 mm per step (see Section 1.8.6.1).
NOTE:
The above figures
0 1
'
c o
' ::~
0 1
'
0 1
'
S t e p ~
1
2
Rotation
Figure 2-92. PG Motor Phase Switching Timing
Platen Gop
[ m m ]
0 . 8
0 . 6 9
1
0.6 }
0.5
0.47
0 . 4
0.33
0 :3 J
1 1
0 . 0 6
0.2
include no manual adjustments.
Figure 2-93. Paper Thickness and Platen Gap
3 4
0 . 4 6
0.3 0.4 0.5 0.7
Poper Thickness
2-101
I
0.8
[mm]
REV.-A