Ref. 2-13 Confidential
This scanner mechanism supports a dual scanning system: ADF scanning and flat-bed
scanning. They automatically switch to the former at the start of a scan operation if the
document front sensor inside the ADF detects a document.
(1) ADF scanning: Document moves across stationary CIS unit
Placing a document face up in the document support activates the document front
sensor, switching to ADF scanning.
The CIS drive mechanism (details below) operates for each scanning command
executed. The CIS unit first moves to the white-level reference film for white level
compensation and then to the ADF scanning position.
The ADF motor then rotates the document pull-in roller to pull the document into the
The document separation roller feeds the pages one at a time, starting from the top, to
the document feed roller, which rotates to move the page in a curve left, down, and right.
The page is scanned as it passes over the CIS unit. It then leaves the machine face
down onto the document cover. The machine inserts subsequent pages under this one
to preserve the document page order.
(2) Flat-bed scanning: CIS unit moves under stationary document
The user lifts the document cover, places a page (or open book) face down on the glass
plate, and closes the document cover. The CIS drive mechanism (details below)
operates for each scanning command executed. The CIS unit first moves to the white-
level reference film for white level compensation.
It then moves right, scanning as it goes. It returns to its home position after the scan.
CIS drive mechanism
The contact image sensor (CIS) unit rides along the CIS rail driven by the CIS drive belt.
Clockwise motion of the CIS motor moves the unit to the left; counterclockwise motion, to the
right. This unit consists of the glass cover, the document illumination LED array, the self-focus
lens array gathering the light reflected from the scanned image, the CIS PCB converts the
light input to pixel data output.