3-30
3.7 OUT-OF-PAPER SENSOR
The printer has a built-in out-of-paper sensor (reflection type photo interrupter) to detect whether the thermal
paper is present or not. An external circuit should be designed so that it detects output from the out-of-paper
sensor and does not activate the thermal head and motor when there is no paper. Doing not so may cause
damage to the thermal head or platen or shorten the life of the thermal head significantly. If the motor is driven
when there is no paper, a load is put on the paper drive system and the life of the printer may be shortened
significantly.
3.7.1 General Specifications
Table 3-20 shows about the out-of-paper sensor used for this printer.
Table 3-20 Out-of-Paper Sensor
Item Specifications
Model GP2S60B
Manufacturer Sharp
Corporation
Figure 3-13 shows sample external circuit of the out-of-paper sensor.
Vdd
470pF
Out-of-paper sensor
47k
Ω
±1%
220
Ω
±1%
LTP01-245
PS
ps
V
G
ps
GND
CPU Port
74HC14
Figure 3-13 Sample External Circuit of the Out-of-Paper Sensor
3.7.2 Precautions for the Out-of-Paper Sensor
The out-of-paper sensor may generate instantaneous abnormal signal. Design the firmware in order
to prevent malfunction due to the abnormal signal. (Recommended frequency: detecting twice every
10 ms
）
