Epson DLQ-3000+, Service Manual

Page: 66 / 262

DLQ-3000+
Rev. A
2-4
2.1.3 PG (Platen Gap) Adjustment Mechanism
PG adjustment is made manually and automatically. In the manual PG adjustment mode, the
proper PG is originally set for the paper to be loaded by manually operating the PG adjust
lever located at the left front of the printer. On the other hand, the automatic PG adjustment
function lets the printer automatically measure the paper thickness and set the proper PG for
the thickness. This mode is activated by setting the PG adjust lever to the automatic side.
Figure 2-3 shows the PG adjustment mechanism.
Slit Disc Paper Thickness Sensor
CR Guide Shaft
Printhead (CR Unit)
Ink Ribbon
Ribbon Mask
Paper
PG Motor
Pinion Gear
Combination Gear
Sector Gear
PGHP Sensor Platen
Figure 2-3. PG adjustment Mechanism
The PG adjustment mechanism located at the left top of the printer mechanism unit consists
of the PG motor, CR guide shaft, sectorial gear, combination gear, PG home position
sensor, and paper thickness sensor., After the PG is determined by the controller circuit
according to the paper thickness, the PG motor rotates corresponding amount. The torque
from the PG motor is transmitted via the motor pinion gear, combination gear and sectorial
gear to the CR guide shaft. Since the shaft is eccentric, the CR on the shaft moves from or
toward the platen as the shaft moves, depending on the direction the motor rotates. Seeing
from the left side of the printer mechanism, the clockwise or counterclockwise rotation of the
CR guide shaft narrows or widens the PG, respectively. The PG home position is detected
when the sectorial gear pushes the actuator on the PG home position sensor.