Service manual

Samsung Electronics 7-1
7. Theory of Mechanism
7-1 Scanner Mechanism
7-1-1 Automatic Document Feeder
(ADF) Mechanism
The automatic document feeder, consisting of
various rollers, ADF rubber pad, and springs,
automatically separates and feeds the pages of a doc-
ument over the scanning area and stacks them on the
document exit tray.
Documents up to 30 pages can be placed in the auto-
matic document feeder for scanning. The
leading edge of the document will move the
document detect sensor lever when the operator
slides the stack into the ADF. The scan motor starts to
rotate when the document detect sensor has detected
the leading edge of the document. The ADF roller
feeds the first page of the document into the feeder.
The scan motor is stopped when the leading edge of
the page actuates the document scan sensor. The
page is now in the scan position.
The ADF rubber prevents multiple sheets from being
feed. Aspring provides forces that the pad places on
the document pages for proper separation.
The scan motor is turned on when the machine is
ready to scan the document and drives the feed roller
at a speed determined by the resolution
selected. The scan motor is stopped after a set
period of time when the trailing edge of the page
releases the document scan sensor. If another page is
detected as the tailing edge of the page releases the
document scan sensor, the next page will be fed to
the scan position. The exit roller pushes the page out
onto the document exit tray where it is stacked.
7-1-2 Contact Image Sensor (CIS)
The contact image sensor unit consist of LEDs, rod
lens array, and a photo sensor. The LEDs illuminate
the document to be scanned when the leading edge
is detected by the document scan sensor. The LEDs
turn off when the document exits the scanner
mechanism.
The LEDs illuminate the document to obtain an
image from the document through the rod lens array,
where the image is translated into voltage
levels.
7-1-3 Document Sensors
There are two document sensors in the scanner
mechanism; the document detect and the document
scan sensor. The document detect sensor, detects
whether or not a document is loaded, and the
document scan sensor detects the scan position of the
document.
The scanner mechanism consists of components which feed, scan, and eject the documents that are to be copied
or transmitted to a remote facsimile unit. These components and their functions are explained below.