REV.-A
● Speed Control
f::
Since a stepper motor is used for the paper feed motor, holding at any position is possible.
Acceleration, constant speed, and deceleration of the paper feed motor are performed by the
firmware, just like the carriage motor. The speed control methods are described below.
Acceleration Control:
The paper feed motor is accelerated in accordance with the acceleration time table. The acceleration
time varies depending on the speed mode. Table 2-14 shows the differences between the speed modes.
Table 2-14. Acceleration/Deceleration Mode
Speed
Mode
Feed Speed
Excitation System
Acceleration/
Deceleration
Constant Speed
I
I I
I
I
1
660 pps
2-2 Phase
7/6
Steps
1.52
mS
I
121
720 PPS
I
2-2 Phase
I
7/6
Steps
I
1.39
mS
I
I
3
780
PIN
2-2 Phase
7/6 Steps
1.28
mS
I
Constant speed control:
The paper feed motor constant speed depends on the constant speed set time, which varies depending
on the speed mode. Table 2-14 shows the set times for constant paper feed motor speed.
Deceleration control:
The paper feed motor is decelerated in accordance with the deceleration time table. The deceleration
time varies depending on the speed mode. The number of deceleration steps for each speed mode are
the same as the acceleration steps at the corresponding speed mode. When the paper feed motor
decelerates and stops, the drive voltage (+36 V) is turned on and off (chopping) so that the motor stops
stably. When the paper feed motor stops, the motor drive control is performed during the drive voltage
chopping operation so that any backlash in the gears of the paper feed mechanism can be taken up.
Paper feed control in the
NLQ mode
When the
NLQ
(Near Letter Quality) printing operation shifts from the first pass to the second pass,
~-
-,
‘.
the phase excitation system for the paper feed motor changes from the 2-2 phase excitation system. “
-
The paper feed motor is driven once using the 2-2 phase excitation system, then once using the 1-2
phase excitation system. Therefore, when the
NLQ
printing operation is on the second pass, the paper
feed motor is held by the 1-2 phase excitation system.
2-56
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