Toshiba ESTUDIO170F, Service Manual

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January 2005 © TOSHIBA TEC e-STUDIO170F PBA Outline and Sensor Functions
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[ 6 ] Front Cover Open Switch / RX Cover Open Switch
Fig.6-19
The front cover open switch is installed on the right frame and the RX cover open switch is installed on
the TX frame respectively to detect the open/closed status of the front cover and the RX cover.
Each switch is connected in series with the supply line of +24V power supply (+24VILS). When the
switch is pushed down by the plate of each cover to turn it on, +24VILS is supplied to each PBA. Then
AC power is supplied to the fuser due to the supply of +24VILS. Since +24VILS is supplied or cut off by
each switch, the open/closed status of each cover can be detected by monitoring the supply status of
+24VILS.
[ 7 ] Toner Empty Sensor
Fig.6-20
The toner empty sensor is installed on the feed upper guide and detects the amount of toner in the
Toner cartridge. Light is radiated into the Toner cartridge. Then, the amount of toner is judged by count-
ing the number of reflected times of the light from the reflecting plate and the reflected time.
When there is toner in the cartridge, the light is not reflected because it is shaded by the toner.
The more the toner runs out, the more the light easily passes through the toner so that the light is easily
reflected.
Plate
Plate
Front cover open switch RX cover open switch
ON
ON
Toner cartridge
Toner empty sensor
Reflecting plate