Epson LQ-570e, Service Manual

Page: 48 / 129

EPSON
LQ-580
Revision
C
Operating
Principles
Printer
Mechanism
48
2.2
Printer Mechanism
This
printer mechanism consists of Printhead, Paper feed mechanism, Carriage movement
mechanism,
Tractor feed mechanism, Platen gap adjustment mechanism, Ribbon feed
mechanism,
PF motor, CR motor, detectors, and so on.
2.2.1
Printhead
The
printhead prints data from the control board on paper using the ink ribbon. The
printhead
is mounted on the carriage unit.
2.2.2
Paper Feed Mechanism
The
paper feed mechanism picks up paper and transports it to the printhead, then ejects it
step
by step or continuously driven by the PF motor. PF motor drives the paper feed
mechanism
gears and the platen roller. The top of form and paper out condition are detected
by
front and rear PE detector, respectively.
2.2.3
Carriage Movement Mechanism
The
carriage movement mechanism carries the carriage unit left and right along the CR
guide
shaft and mechanism frame and stops it at any position for printing. It is driven by the
torque
sent from the CR motor via the timing belt. Home position is detected by the HP
(home
position) detector at power on and CR motor phase changing timing.
2.2.4
Tractor Feed Mechanism
The
tractor feed mechanism feeds continuous paper to the printhead and ejects it. The
torque
from the PF motor is transferred to the tractor unit via the release mechanism in the
paper
feed mechanism. The release mechanism switches the PF motor torque between cut
sheet
feeding and continuous paper feeding by the release lever. This printer is equipped
with
several tractor feeding methods (front / rear push tractor feeding, front / rear push &
pull
tractor feeding and front / rear pull tractor feeding), which is selected according to the
tractor
unit setting positions and the lever positions. The tractor detector detects the release
lever
setting position in cut sheet feeding or continuous paper feeding.
2.2.5
Platen Gap Adjustment Mechanism
The
platen gap (the gap between the platen and the printhead) adjustment mechanism
consists
of CR guide shaft, parallelism adjustment bushing, PG adjust lever and PG
detector.
PG adjust lever is attached to the left side of the CR guide shaft. The bushings are
attached
to the both sides of the frame. As the both sides part of CR guide shaft is eccentric
toward
external form of it, printhead approaches or recedes from the platen roller to turn the
PG
lever forward or backward. PG detector detects PG lever position. If the lever is set 2nd
and
more position, the printer gets into copy mode.
2.2.6
Ribbon Feed Mechanism
The
CR motor drives the ribbon feed mechanism via the timing belt. The ribbon feed
mechanism
has the sun and planetary gear system. No matter the carriage unit is driven left
and
right, the ink ribbon is driven in one direction.