Transmission Section; Actions Of Transmission Section - Toshiba DP120F Service Manual

2. Transmission Section

2.1 Actions of Transmission Section

• Scanning single page documents:
The Document guide is set according to the document size. When the document is set,
the Document sensor detects the presence/absence of document to be scanned. When
the Document sensor detects presence of document, the TX motor starts rotating. The
TX motor drives the Kick roller, ADF roller and TX drive rollers. The document is pulled in
by the ADF (Automatic Document Feed) roller and is fed by the TX drive rollers. When the
Document position sensor detects the top edge of the document, the machine returns to
the standby status and waits.
By pressing the [COPY] key + (number of copies) + [START] key, the standby status is
canceled and the LEDs for scanning are turned ON. At the same time, the TX motor
starts rotating and feeds the document to the CIS unit. The document is read, line by line
(in units of one scanning line width). When the Document position sensor detects the
bottom edge of the document; the document is scanned for a certain value then the LEDs
are turned OFF and scanning is completed. The document is fed out by the TX drive
rollers.
If the Document position sensor does not detect the top edge of the document within the
specified time after the Document sensor detects the presence of document, a document
jam is indicated.
• Scanning multiple page documents:
Basically the same as feeding a single page document. The main difference is the func-
tion of the ADF unit to prevent multi-page feeding.
The ADF unit touches the ADF roller. The friction caused when two document pages are
pulled in along with the rotation of the ADF roller are classified into three categories - one
is between the lower page and the ADF roller, another is between the upper page and
ADF unit, and the third is between the document pages. The document page is fed at the
position with the least coefficient of friction of these three.
As the ADF roller surface and the ADF unit are made of rubber, the position with the least
coefficient of friction is between the document pages. Therefore, the two pages glide on
each other, only the lower page is fed along with the rotation of the ADF roller, and the
upper document page stays at the set position.
However, normal feeding is not performed when the friction between the pages is exces-
sive. In this case, document jams may occur or multiple pages may be fed together.
DP120F/DP125F Mechanical Description 5-2 March 2000 © TOSHIBA TEC