Document Detection; Outline; Document Presence/Absence Detection; Detection Of Last Document - Canon DADF-P1 Service Manual

Chapter 2

2.3 Document Detection

2.3.1 Outline

This machine detects an document using either one of the two methods depending on the print mode.
- Normal print mode (other than mixed size print mode and banner paper mode)
- Mixed size print mode and banner paper mode
a. Normal print mode (other than mixed size print mode and banner paper mode)
In the normal print mode, the following four document detection functions are used:
Document presence/
absence detection
Last document detection
Initial document size
detection
- Longitudinal direction
- Lateral direction
b. Mixed size print mode and banner paper mode
In the mixed size print mode and banner paper mode, the following three document detection functions are used:
Document presence/
absence detection
Last document detection
Document length detection Detects the document length

2.3.2 Document Presence/Absence Detection

The Document set sensor (PI11) detects presence/absence of a document on the document tray.
When a document is placed on the document tray, the detection lever moves the light shielding plate to allow light to pass thorough the photo interrupter. Thus, the
Document set sensor (PI11) generates an document detection signal (EMPTY) to notify the host machine that an document is placed on the document tray via the
ADF drive PCB.

2.3.3 Detection of Last Document

The last document detection sensor (PI3) and Document set sensor (PI11) detect whether the document being picked up is the last one.
When the trailing edge of the last document has moved past the last document detection lever, the detection lever moves the light shielding plate to allow light pass
through the photo interrupter. Thus, the last document detection sensor (PI3) generates a last document detection signal (LAST). When the last document has moved
past the document sensor (PI11), an document absence signal (EMPTY) is generated to notify the host machine that an document being picked up is the last one
via the ADF drive PCB.
2-4
Function
Detects whether there is an document on the
document pickup tray.
Detects whether the document being picked up is
the last one.
Detects the length of the document placed on the
document pickup tray.
Detects the width of the document placed on the
document pickup tray.
Function Description
Detects whether there is a document
on the document pickup tray.
Detects whether the document being
picked up is the last one.
according to the distance from the
position where the read sensor (PI7)
turns on to the position where the read
sensor (I7) turns off.
ADF driver PCB
Detection lever
PI11
T-2-3
Description
Document set sensor (PI11)
Last document detection sensor
(PI3)
Document length sensor 1/2 (PI4/
PI5)
Document width sensor 1/2 (PI2/
PI1)
T-2-4
Sensor used (symbol)
Document set sensor (PI11)
Last document detection sensor (PI3)
Read sensor (PI7)
Document
F-2-6
Sensor used (symbol)
0010-3898
0010-3899
0010-3900