CHAPTER 2
2 - 15
COPYRIGHT
2000 CANON INC. CANOSCAN N650U/N656U/N1220U REV.0 JUNE 2000 PRINTED IN JAPAN (IMPRIME AU JAPON)
2. Image scanning operation
When the contact image sensor moves to the image scanning position, the control program
turns the SP signal to "L" three times per line to light the LED in order of red, green and blue,
and reads the image signal corresponding to each red, green and blue lights. The reading cycle
of 1 line is 15.48 msec.
When scanning a grayscale image, only green LED is ON and the image signal is processed.
Figure 2-13
SP
RLED
GLED
BLED
Image signal
output
R
G
B
5.16ms 5.16ms
5.16ms
R
G
B
R