Toshiba e-studio550 Service Manual page 112

7. 5. Scanning Section
Light reflected from original surface is directed to the CCD which performs the opto-electronic conversion,
and the optical image data are converted into an electrical signal. This analog signal undergoes the A/D
conversion processing and is changed into a digital signal. The signal then undertakes various corrective
processes necessary for image formation.
CCD
(1) Opto-electronic conversion
The CCD elements convert the optical signal into electrical signal. (
(2) Signal amplification
Amplifies the electrical signals converted in the CCD.
(3) A/D conversion
Converts the analog signal into the digital signal.
(4) Shading correction
The shading correction is applied on the signal read by CCD. (
7. 6. Writing Section
The image signal processed by the PLG board is processed by the ASIC for writing control and laser drive
board. The laser is controlled based on the signal, writing data on the drum.
(1) Setting the effective image area ........................ • Top, bottom, left and right margins
(2) Horizontal synchronization signal (H-Sync) ....... • The reference clock signal in the printer section
clock generation section
(3) Laser drive section ........................................... • ON/OFF control of the semiconductive laser and
e-STUDIO550/650/810 IMAGE PROCESSING
Signal
amplification
conversion
A/D Shading
correction
Chap.6.5.2.)
synchronized with the H-Sync and its signal.
APC (Auto Power Control) control.
7 - 8
Next stage
Chap.6.5.1)
JUNE 2002 © TOSHIBA TEC