Canon 1000S, Руководство по обслуживанию

Страница: 114 / 840

3. OPERATION AND TIMING
COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-70
3. Density Correction
The relationship between video signals and
image densities is as shown in Figure 3-413. As
can be learned, using the video signals as they are
for laser exposure will not result in the faithful
reproduction of image densities.
Figure 3-413
To ensure that the image density will be reproduced throughout the entire range of the video signals, the
video signals are converted along the correction curve (Figure 3-414), thereby bringing the output
characteristics closer to the ideal characteristics.
Figure 3-414
The correction curve for conversion is stored in the density correction RAM on the video controller in
relation to the data for SALT and PASCAL*.
*See chapter 3. V. IMAGE FORMATION SYSTEM, C. Stabilizing Image.
Figure 3-415
The video data (YMCBk) is corrected against the correction curve for correction and sent to the laser
driver.
Image density
Video signal
0 255
Output image darker
than original
Output image lighter
than original
Video signal input
0
255
255
Correction curve
Ideal characteristics
Image density
Video signal
0
255
Video signal output
Density correction
Video controller PCB
Y,M,C,Bk
Video signal
DC controller PCB
SALT/PASCAL data
Image processor PCB