Scanner Mechanism; Document Feeding And Ejecting Mechanism; Scanner - Brother MFC-8220 Service Manual

CHAPTER 3 THEORY OF OPERATION
2.2

Scanner Mechanism

ADF document support
Document take-in roller ASSY
2.2.1

Document feeding and ejecting mechanism

This mechanism consists of the ADF document support, automatic document feeder (ADF),
document ejection roller ASSY, and document sensors. (For details about the sensors, refer to
Section 2.4.)
If you set documents on the ADF document support with their faces down and start scanning
operation, then the scanner motor rotates so that the ADF (which consists of the document
take-in roller ASSY, nip-related parts, separation roller ASSY, and ADF parts) feeds those
documents into the equipment, starting from the bottom sheet (first page) to the top (last
page), page by page. Each document advances with the document feed roller ASSY to the
scanner, and then it is fed out of the equipment with the document ejection roller ASSY.
2.2.2

Scanner

The scanner uses a contact image sensor (CIS) unit which consists of an LED array
illuminating documents, a self-focus lens array collecting the reflected light, a CIS PCB
carrying out photoelectric conversion to output picture element data, and a cover glass on
which a document advance. When the document passes between the document pressure bar
and the cover glass, it is scanned.
Nip-related parts
Document
Separation roller ASSY
Pressure rollers
Document front sensor actuator
ADF parts
Document feed roller ASSY
Document rear sensor actuator
Pinch rollers
CIS unit
Fig. 3-20
3-14
Document pressure bar
Document ejection roller ASSY
ADF document output support
(Front)