Brother FAX 1840C, Service Manual

Page: 55 / 401

3-4
Confidential
3.2.1 Scanner Mechanism
3.2.1.1 Document feeding and ejecting mechanism
This mechanism consists of the document support, automatic document feeder (ADF), document
feed roller, document ejection roller ASSY, and document sensors. (For details about the sensors,
refer to
Section 3.2.3. )
Placing documents face down on the top cover and starting the scanning operation activate the
scanner motor so that the ADF (consisting of the document pull-in roller, nip piece, separation roller
and ADF parts) feeds the documents into the machine,
starting from the bottom (first page), page
by page. Each document advances with the document feed roller to the scanner, and then it is fed out
of the machine with the document ejection roller ASSY.
Document nip piece
Document
pull-in roller
Document front sensor actuator
Document rear sensor actuator
Document feed roller
Document pressure roller
Document separation roller
CIS unit
Pinch rollers
Document pressure bar
Document ejection roller
CIS glass
Document rear sensor
Document front sensor
Scanner motor
ADF parts
Document
Document support
(Front)
3.2.1.2 Document scanning mechanism
The scanner uses a contact image sensor (CIS) unit which consists of the document illumination
LED array, the self-focus lens array gathering the light reflected from the scanned image, the CIS
PCB converting the light input to pixel data output, and CIS glass on which a document advances.
When the document passes between the document pressure bar and the cover glass, it is scanned.