e-STUDIO160/200/250 SCANNER 7 - 14 December 2002 TOSHIBA TEC
7.7 Automatic Original-Size Detection Circuit (e-STUDIO200/250 series)
This circuit detects the original size (standard sizes only) using reflection-type photosensors on the base
frame of the optical unit.
7.7.1 Principle of original-size detection
The reflection-type photosensors are located on the base frame of the optical unit. Each photosensor
comprises an infrared light emitting diode (LED, light-emitting side) and a phototransistor (light-receiving
side). When an original is placed on the original glass, the light emitted by the LED’s is reflected by the
original and led to the phototransistor. In this way, the presence or absence of an original is detected by
whether reflected light exists or not.
[ASD/AUD/CND/SAD/MJD models] [NAD model]
Original
Original glass
APS-1, 2, 3, 4, 5
Original
Original glass
APS-2, 3, 4, 5, 6
08-07-01 08-07-02
7.7.2 Original size detection
(1) If the copier is set in the original size detection mode, the carriage 1 is set at its home position.
(2) Detection is performed in an instant when the platen cover is opened, each sensor receive the reflect-
ing light and the condition of a matrix shown in (4) are satisfied.
(3) Original size detection is performed when the output signals from each sensor are input to the scan-
ner MPU (IC1) on the scanner control PWA.
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