Canon fax basic 2000 サービスマニュアル

READING SECTION

3–4

2.2

Book Reading Method

Book reading is a method where the document (thick document) is placed

on the copyboard glass and is read by the contact sensor. This sensor is

moved backwards and forwards in the 

 direction along the

guide shaft by motor drive transmitted to the belt via gears.

Fig. 3-4   Book Reading Method

2.3

ADF Type

One of the sheet reading methods is the ADF (Auto Document Feeder)

separation method. There are two main ADF types, flat-bed type and drop-

in type.

2.3.1 Flat-bed type

A feature of this ADF type is consistent performance during loading of

documents, which makes it suitable for loading a document comprising

many sheets.

On the other hand, however, it costs more as a forwarding roller is required

in the mechanism and more installation space is required. 

sometimes occurs due to over-insertion of document sheets when the docu-

ment is loaded, or, alternatively, sheets being 

 due to an insufficient

amount of sheets being loaded.

• Explanation of flat-bed type operation

By this type of ADF mechanism, drive from the document feed motor is

transmitted to the rollers required for document forwarding, separation,

feed, and eject via gears and belts.

To control ADF operation, the 

 counts the number of step pulses of

the document feed motor, and two photointerrupter type sensors, document

sensor (DS) and document edge sensor (DES), installed on the actuator

arm detect the feed state of the document.

Copyboard glass

Contact sensor