Canon NP6085 Service Manual page 106

3. OPERATIONS AND TIMING
2. Operation
The DC controller measures the output of the
original size detection sensors at intervals of 0.2
sec for 15 sec after the copyboard cover sensor
(Q89) turns ON or until the Copy Start key is
pressed.
If an original exists over an original sensor, the
output of the detection circuit is of a specific value
regardless of the angle of the RDF, since the orig-
inal size sensor receives the light reflected by the
original.
If no original exists over the original sensor, on
the other hand, the output of the detection circuit
immediately after Q89 turns ON is small. The out-
put increases when the copyboard cover is fully
closed, since the detection circuit then receives
the light reflected by the copyboard cover sheet.
As such, the microprocessor identifies the
presence of an original if there is no change to the
output of the detection circuit and identifies the
absence of an original in response to a change.
This way, a black original may also be identified
as to its size.
Original
Q89 ON
Original size sensor
3-48
COPYRIGHT © 1996 CANON INC.
RDF
DC controller PCB
(The thickness of arrows represents the size of the level.)
Figure 3-218
Reference:
1.If the original is thick and the RDF does
not close fully after Q89 has turned ON,
the level of the sensor output will remain
unchanged. In consideration of this, the
measurement at the moment Q89 goes
ON is compared against the slice level to
determine the original size if neither of
these sensor outputs changes.
2.If the RDF is open (Q89 OFF), the origi-
nal sizes will be shown in the touch panel
display and select the original size. (If the
A5, A5R, STMT, or STMTR are placed on
the copy board, same as above.)
Approx. 30˚
Q89 ON
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
DC controller PCB