Toshiba DP120F, Service Manual

Page: 355 / 706

DP120F/DP125F Circuit Description 7-46 March 2000 © TOSHIBA TEC
3.13 Document Detect Circuit
The document detect circuit consists of the I/OP-2 GA (IC48) and other peripheral devices. It
detects the presence or absence of a document, document transport status, and document
jams through the document sensor and document position sensor which are connected to
CN10 on the Mother PBA.
When a document is placed, the actuator of the document sensor is pushed down by the
document to turn on the sensor. This causes the DDET signal to be LOW and input to the I/OP-
2 GA to detect the presence of a document.
When the document placed is transported by the TX motor to before the scanning position, the
actuator of the document position sensor is pushed down by the document to turn on the
sensor. This causes the SCNP signal to be LOW and input to the I/OP-2 GA to detect that
scanning the document is ready.
Then, if the SCNP signal does not return to HIGH level even after the transport of the document
has started and a fixed time has elapsed, the occurrence of a document jam will be assumed.
Fig. 7-3-13
07-03-13
Signal Name Type Active Description Destination
DDET I L Document Detect Signal I/OP-2 GA
SCNP I L Document Position Detect Signal I/OP-2 GA