Automatic Original Size Detection Circuit; Principle Of Original Size Detection; Process Of Detection Of Original Size - Toshiba e-STUDIO453 Service Manual

6.6 Automatic Original Size Detection Circuit

This circuit detects the size of original (standard sizes only) using the reflection type photosensors ar-
ranged on the base frame of the scanner unit.

6.6.1 Principle of original size detection

Reflection type photosensors are placed on the base frame of the scanner unit as shown in the Fig.
6-601. Each sensor consists of an infrared light emitting diode (LED) on the light emitting side, and a
phototransistor on the light receiving side.
When there is an original on the original glass, light beams from the LEDs are reflected by the original
6
and led to the phototransistors. This means that the presence of the original is detected by the pres-
ence of reflection.
[A4 Series]
Orgnal
APS-3
APS-

6.6.2 Process of detection of original size

(1) When the equipment is in the original size detection mode, carriage-1 is set at its home position.
(2) When the platen cover is opened, the sensors receive the light reflected from the original and
if one of the matrix conditions shown in (4) for original sizes are met, the size of the original is
instantly detected.
(3) The output signal from each sensor is input to CPU on the SLG board to determine the size of the
original.
[A4 Series]
Reflection type
photosensor
e-STUDIO350/352/353/450/452/453
SCANNER
Original glass
APS-C
APS-2
APS-R
APS-C
CPU
APS-3
APS-2
APS-
GND
Fig. 6-602 Original size detection circuit
[LT Series]
Original
APS-R
APS-3
APS-2
Fig. 6-601
V
DD
[LT Series]
Reflection type photo-
sensor
PWA-SLG
6 - 12 © 2003 - 2008 TOSHIBA TEC CORPORATION All rights reserved
Original glass
APS-R
APS-C
V
DD
APS-R
APS-C
CPU
APS-3
APS-2
PWA-SLG
GND