C. Controlling the Blank
Exposure Lamp (LED)
1. Outline
The blank exposure lamp is an array of LEDs
(124 pcs.).
All of the LEDs (124 pcs.) turn ON when the
drum is rotating except when an original is being
exposed, potential is controlled, or measurements
are taken for AE, thereby preventing adhesion of
excess toner on the photosensitive drum. The two
LEDs at the rear and the two LEDs at the front are
kept ON at all times whenever the drum is rotat-
ing.
The LEDs are turned ON using a static activa-
tion method (serial data transfer).
2. Controlling the Activation in Reduce Mode
When the original is exposed for a reduced
copy, as many LEDs (rear) as corresponding to
the selected reduction ratio are turned ON to
black out (white out) the non-image areas. At this
time, the LEDs at the front are also kept ON to suit
the copy size.
3. Controlling the Activation in Direct Mode
When making copies in Direct mode, the LEDs
at the rear and the front are turned ON to suit the
selected copy size, thereby blacking out (whiting
out) the non-image areas.
When a default reproduction ratio is used or
when a default copy size is selected in Direct
mode, a non-image width is created at the front
and the rear as shown in Table 3-304 (standard
frame erasing).
The non-image width may be set to 0 mm in
service mode.
4. Controlling the Activation in Sheet/Original
Frame Erasing Mode
In sheet frame erasing mode, LEDs are turned
ON so that a width of about 7 mm along the
copies will be free of toner.
Reference:
When the multifeeder is used, a specific
copy size may be selected or not selected
(free); if a copy size is selected, frame eras-
ing is executed accordingly. (Otherwise,
frame erasing will be executed based on
maximum size (297x432mm)).
Figure 3-312
In original frame erasing, LEDs are turned ON
so that a width of about 2 mm corresponding to
the sides of the original will be free of toner.
Table 3-304
3. OPERATIONS AND TIMING
COPYRIGHT © 1996 CANON INC.
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3-61
,,,,,
,,,,,
,,,,,
7 mm (approx.)
7 mm
(approx.)
7 mm
(approx.)
2.75mm
Feeding direction
Paper size
Non-image width
A4R, B5R, B4, A3, LTR R
2.75
±
2.3mm
Other sizes
3.0
±
2.55mm
Содержание NP6085
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