Panasonic KX-MB283BR Service Manual page 39

6.10.5. REGISTRATION & MANUAL PAPER SENSOR
This sensor detects whether the recording paper is at the sensor position.
When the recording paper is detected, the shelter plate lets the sensor light pass.
So the photo-transistor turns on, and input signal of IC300-AF20pin becomes low level.
When the recording paper is not detected, the shelter plate closes the sensor light.
So the photo-transistor turns off, and input signal of IC300-AF20pin becomes high level.
6.10.6. PRINT TIMING SENSOR
This sensor detects whether the recording paper is at the printing position.
When the recording paper is detected, the shelter plate lets the sensor light pass.
So the photo-transistor turns on, and input signal of IC300-W26pin becomes low level.
When the recording paper is not detected, the shelter plate closes the sensor light.
So the photo-transistor turns off, and input signal of IC300-W26pin becomes high level.
Photo-transistor
Paper exists ON
No paper OFF
Photo-transistor
Paper exists ON
No paper OFF
Signal (IC300-AF20pin)
Low level
High level
Signal (IC300-113pin)
Low level
High level
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KX-MB283BR