Toshiba e-studio550 Service Manual page 91

6. 4. Control for Exposure Lamp
6. 4. 1. General description
Control circuit of the exposure lamp consists of the following 3 blocks.
(1) Lighting device for the Xenon lamp (Inverter)
Turns the exposure lamp ON/OFF.
(2) CCD sensor circuit
This circuit works to the convert the reflected light amount from the original surface and the shading
correction plate to the electrical signals. The reflected light amount from the shading correction plate is
read to control the exposure amount.
(3) Image processing circuit
The output signals from the CCD are digitized and the image processing such as gamma correction
and shading correction is applied to them.
Original
PWA-CCD
CCD sensor
JUNE 2002 © TOSHIBA TEC
Shading correction plate
Exposure lamp (Xenon lamp)
PWA-CCD
Image processing
circuit
Construction of exposure lamp control circuit
PWA-SLG
A/D
6 - 7 e-STUDIO550/650/810 SCANNING SECTION
Lighting device
for Xenon lamp
(Inverter)
Scanner
Main CPU
CPU
IC37