Photosensors; Cover Open Circuit - Oki OKIFAX4550 Maintenance Manual

7.2

Photosensors

The photosensors mounted on this circuit board/sensor board supervise the paper running state
during printing. These four photosensors are used in this printer as listed below. All of their outputs
enter 46F/R46 board.
1) PS1 (photosensor 1): TNRSNS
Detects the lack of the toner.
2) PS2 (photosensor 2): PSIN
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.
3) PS3 (photosensor 3): PSOUT
Supervises the paper feed according to the time of arrival at the sensor and the time of passage
of paper.
4) PS4 (photosensor 4): WRSNS
Detects the leading part of sensor.
Supervises the paper running state.
7.3

Cover open circuit

The cover open circuit consists of CVSW. When the Cover-Main is opened, the cover open
microswitch (CVSW) on the OLHV/TLHV board is turned off to cut the supply of H5V to the high-
voltage power supply circuit. As a result all high-voltage outputs are interruptted. At the same time,
the CVOPN-N signal is sent to the control board to notify it the off state of the microswitch, and the
control board performs the cover open processing.
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