Canon iR3245, Service Manual

Page: 170 / 746

Chapter 5
5-14
5.3.4.3 Detection Operation Overview
0019-4677
iR3225 / iR3225N / iR3235 / iR3235N / iR3245 / iR3245N
1) Standby state (The following is in case that the AB type, A4R size is set.)
CCD unit: shading position
LED: OFF
Original sensor: OFF
F-5-15
2) ADF opened
CCD unit: moves to original detection position
LED: OFF
Original sensor: OFF
F-5-16
3) ADF closed
CCD unit: in original detection position
LED: OFF to ON
Original sensor: in original detection operation
- With the ADF angle at 25 deg or less, the external light is blocked at the original width area. Then, the machine determines that the original is absent at the points
that the external light is detected (external light search operation). When the original mount sensor (rear) detects [close], original size detection is started. In this
case, B5/B4/A4/A3 size is eliminated at this point.
- After external light search, LED is turned ON at main scanning side and the CCD checks the reflection light (4 points). For sub scanning direction, original sensor
detects the size.
F-5-17
F-5-18
4) ADF fully closed (5 deg or less)
CCD unit: in original detection position
LED: ON
Original sensor: in original detection operation
For 2 sec from the original mount sensor (front) detected [close], this monitors the changes of output level of each sensor. The machine determines that the
original is present in the position where the level is not changed.
The machine identifies the original size by the combination of level changes at 5 points (in case of AB type size).
F-5-19
CCD original detection position
CCD unit
Original sensor
Reader unit
ADF
Position of detection 1
Position of detection 2
Position of detection 3
Position of detection 4
Copyboard glass
(External
light)
External
light
25
5