Epson LQ-2550 Technical Manual page 137

Carriage Motion Area and Speed Control
The carriage motion area is shown in Figure 2-84. This is mainly divided into three areas: 1 ) acceleration
area, 2) printable area, and 3) deceleration area. The printer has five carriage speeds modes.
Acceleration area
I
1
1
1
I
1
1
1
1
t
1
1
1. Acceleration Control
When the carriage speed is either O or 1, the carriage is accelerated for 60 steps using 2-2
switching. When the speed is 2, 3, or 4, the carriage is accelerated for 120 steps using 1-2
switching.
2. Constant Speed Control
Within the printable area, the carriage moves at a constant speed except when the logic seeking function
is active. When the logic seeking function isactive, printing is performed after phase switching for 8
steps (speed O orl) or 16 steps (speed 2, 3, or 4).
3. Deceleration Control
When the speed is O or 1, the carriage is decelerated for 60 steps using 2-2 phase switching.
the speed is 2, 3, or 4, the carriage is decelerated for 120 steps using 1-2 phase switching.
4. High Speed Skip
When spaces (20H) continue for 10 characters or more during text printing, high speed skipping (speed
O = 4000
printing time.
a) Acceleration control:
b) Constant speed control:
c) Deceleration control:
Printable area 13.6-
I
1
1
1
1
1
8 step i
1
Figure 2-84. Carriage Motion Area
shown in Figure 2-85 and is used to shorten the
When shifting to the high speed skip mode from thel-2 phase
switching at speed 2, 3, or 4, the current setting value is changed to
that of speed O and the switching system is changed to 1-2 phase
switching.
The carriage is moved at 4000 PPS.
When returning to the 1-2 phase switching at speed 2, 3, or 4 from
the high speed skip mode, the switching system is changed from 2-2
to 1-2 after deceleration control is performed in the 2-2 phase
switching mode. At this time, a margin for one character is used.
2-91
816 step
REV.-A
Deceleration area
.
1
1
1
1
1
1
60 step
1
1
1
1
phase
phase
When
. . . . .