Document Feed Section - Canon FAX L1000 Service Manual

FAX-L1000 Chapter 3: Technical Reference
2.3 Scanner Section
The scanner section comprises the document feed section and the optical section.

2.3.1 Document feed section

a) Document feed function
a-1) ADF (auto document feed) function
The ADF feeds up to 50 pages
separates each page with the separation roller (upper) and separation roller (lower), passes
the page over the contact sensor unit, then ejects the paper to the document output tray.
*1
: Letter/A4 size: up to 50 pages, Legal size: up to 20 pages
B4 size (AE only): up to 20 pages
a-2) Document jam detection function
The document jam detection function is to detect eject paper jams and over-length
documents with document sensor (DS) and document edge sensor (DES).
b) Document feed section structure
b-1) ADF structure
In the ADF structure, the rollers needed for document pickup, document separation,
document feed, and document ejection are driven via gears with the power for the stepping
pulse type document feed motor.
The document stopper is installed to position documents correctly and reduce feed errors
due to documents inserted too deeply or insufficiently. When document transfer begins,
the document stopper goes up, and documents are separated one at a time and fed with
pickup roller and the separation rollers.
After separation, the document is fed to the contact sensor section with the document feed
roller. The document feed roller turns faster than the separation roller to prevent the
document from slackening between the document feed roller and the separation roller. The
separation roller is pulled by the document feed roller.
The document fed to the contact sensor section is pressed by a white sheet above the
contact sensor to prevent it from lifting during scanning. To correct shading, the white
level is detected from the white sheet immediately before the paper passes through the
contact sensor.
The document scanned with the contact sensor is delivered to the output tray with the
document eject roller.
The ADF is controlled by the SCNT board's main CPU counting the document feed motor
step pulses, and the photo-interrupter type document edge sensor
document feed sensor*
*2
: DES
*1
4
equipped with actuator arms detecting the document feed status.
*3 *4
: DS : DFS
of documents placed on the document feeder tray,
3-30
*2 *3
, document sensor and