Epson LQ-2550 Technical Manual page 55

2.1.2.2 Platen Gap Adjustment Mechanism
This mechanism sets the platen-printhead gap according to the paper thickness. Figure 2-5 shows the
platen gap adjustment sequence.
NOTE: Also, the gap can be ajusted by control panel operation (Refer to section 1.8.6. 1.).
Paper Thickness
Start
Detection
Paper Thickness Detection Mechanism
Figure 2-6 shows the paper thickness detection mechanism. The PT sensor lever is driven by the PT
solenoid when it is energized. The distance that the PT sensor lever moves is monitored by the TCR
on the PT sensor, and the detected value is converted into a voltage and transferred to the control circuit.
Table 2-4 lists the specifications of the PT solenoid and Table 2-5 lists the specifications of the PT sensor.
Item
Resistance
Drive Voltage
Item
Type
Drive Voltage
Platen Gap
Adjustment
Figure 2-5. Platen Gap Adjustment Sequence
Platen
PT Sensor Lever
Figure 2-6. Paper Thickness Detection Mechanism
Table 2-4. PT Solenoid Specifications
Description
65 ohms
35 VDC
Table 2-5. PT Sensor Specifications
I
Description
Conductive rubber
12 VDC
Printhead Drive
Setup Completed
Mode Selection
\
I
1
10%
I
+ 1.5 V, –2.5 V
2-8
Remarks
Remarks
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