Canon iR C1020 Series, Service Manual

Page: 104 / 408

Chapter 5
5-4
5.2.2 Basic Sequence of Operation in Response to a Press on the Start Key (book)
0019-8966
F-5-5
*1 Gain correction: The gain ratio of the analog video signal output from CCD is adjusted to be a fixed value.
*2 Move shading correction: Even when the document density is constant, the CCD output level does not become constant due to the following reasons.
- Variation in pixels for CCD
- Difference of the transmitted light intensity between the center and the surrounding of the lens
- Difference of the light intensity between the center and the surrounding of the document lamp
- Deterioration of the document lamp
Shading correction is performed to correct unevenness of the CCD output level.
F-5-6
* Book Position: the position at which the motor is accelerated to prepare for reading.
Reader motor
(M12)
Document lamp
(LAMP1,2)
Reader HP sensor
(SR717)
STBY SREADY
HP shift
HP shift
Start key ON
: Motor forward
: Motor reverse
: Reader HP sensor ON
: Document lamp ON
HP Book Position
Move shading correction *2
Book Position shift
Scan movement
HP Read end position
Gain correction *1
Book Position *
Home position
(Shading position)
Read start position
2. Gain correction
Read end position
3. Move shading correction
4. Original scanning
1. Document lamp ON
(At lamp OFF only)