Oki B 4100 Maintenance Manual page 444

5-7 Photosensors
The photosensors mounted on this circuit board/sensor board supervise the paper running state
during printing. These six photosensors are used in this printer as listed below. All of their
outputs enter IOGA for referring to and processing by the CPU.
1) PS1 (photosensor 1): PSOUT
Supervises the paper feed according to the time of arrival at the sensor and the time of
passage of paper.
2) PS2 (photosensor 2): WRSNS
Detects the leading part of sensor.
Supervises the paper running state.
3) PS3 (photosensor 3): PSIN1
Detects the leading part of the paper and gives the supervision timing for switching from
hopping operation to feeding operation. Supervises the paper running state and the paper
size according to the paper arrival time and running time.
4) PS4 (photosensor 4): PAPER
Detects the end of the paper.
5) PS5 (photosensor 5): PSIN2
Not used
6) PS6 (photosensor 6): TONER
Detects the lack of the toner.
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