Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
This invention relates to a sheet re~oving device
for an electrophotographic copying machine, and more partic-
ularly to a sheet removing device which serves, after image-
transfer, to strip the sheet off a photosensitive body.
Hitherto, electrophotographic copying machines
using sheets which are cut into a predetermined size have
been provided with devices for stripping the sheet, after
image-transfer, off a photosensitive body so as to feed the
sheet smoothly to a fixing station. However, there some-
times occurs a failure in ~tripping the sheet off the photo-
sensitive body. To overcome such a disadvantage, the afore-
said device has been provided with a detector for alerting
the machine operator that a mis-strip has occurred to allow
the operator to stop the copying machine and remove the
sheet off the photosensitive body. This operation is both
time consuming and troublesome and, in the case of small-
si~ed sheets, it may be necessary to remove the photosensitive
body from the copying machine to strip off the sheet, result-
ing in the lowering in working efficiency as well as givingrise to the probability of damaging the photosensitive body.
This invention is directed to avoiding the afore-
said disadvantages by providing a sheet removing device for
use in an electrophotographic copying machine which removes
an-unstripped sheet from a photosensitive body in a short
time by providing feed rollers which start to rotate in
reverse upon a stripping failure.
In accordance with one aspect of this invention
there is provided in an electrophotographic copying
machine wherein a developed latent image is produced on a
photosensitive body and transferred to a copy sheet which
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is thiereafter stripped from the photosensitive body for
further processing, a sheet removing device comprising: a
reversible feed roll pair adapted to feed sheets to the
photosensitive body for transferring a developed latent
image thereto; detector means for detecting a failure in
stripping a sheet off the photosensitive body, and control
~ieans actuated by said detector mecms to reverse said feed ro11
pair to pull the mis-stripped sheet backward of~ the photo-
sensitive body.
The above and other objects, features and advan-
tages of thie present invention will become clear from the
following description, taken in conjunction with the
accompanying drawings which show by way of example a pre-
ferred embodiment of thie invention.
i5 - BRIEF DESCRIPTION OF THE DRAWINGS:
-
The accompanying drawings illustrate a preferredembodiment of the present invention, in which:
Figure 1 is a side view;
Figure 2 is a front view of the driving portion
of rollers for feeding transfer-sheets; and
Figure 3 is an explanatory view of another embodi-
ment-of a guide plate.
DESCRIPTION OF THE PREFERRED EMBODIMæNT
Referring to the accompanying drawings, thiere is
shown at 1 a photosensitive body of an electrophotographic
copying machine (not shown). Provided below said photo
sensitive body is a sheet tray 2 which houses therein
sheets 3 in a stackèd manner, each sheet being cut into a
predetermined size. Designated at 4 is a feed roller for
feeding the sheets 3 to the photosensitive body 1, one by
one. A guide plate 5 is provided between the sheet supply
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tray 2 and the photosensitive body 1, the guide plate being
adapted to rest in the position as indicated by the solid
line in Figure 1 while the sheet is being fed and being
adapted to move its tip end around a shaft 5a to reach to
the position as indicated by the dotted line in Figure 1 so
as to feed the sheet in a reverse direction~ A pair of
rollers 6 and 7 for feeding transfer-sheets are provided
between the guide plate 5 and the photosensitive body 1,
the rollers being adapted to rotate in a contacting relation-
ship with each other to feed transfer sheets. Roller 6 isadapted to be driven in both a forwarding or reversing
direction by suitable means, such as reversible motor 15.
'Defined at 21 is a corotron which is provided
below the photosensitive body 1. A no~zle 22 adapted to
inject air toward the photosensitive body 1 is provided
for stripping a sheet off said photosensitive body. The
sheet 3 stripped by the nozzle 22 is transferred to a fix-
ing station (not shown) by a transfer-sheet feeding device
23. Provided above the nozzle 22 in a close contacting
relationship with the photosensitive body 1 is a fol]ower
24a which forms part of a detector 24 which detects a
failure in stripping a sheet off the photosensitive body.
The follower 24a is connected to a switch lever 24c of the
switch 24b. When the sheet 3 which fails to strip off the
photosensitive body 1 contacts with follower 24a, the
switch 24b is operated. The switch 24b is connected to a
warning lamp 25 which indicates a stripping failure, and
to the driving portion of the guide plate 5 and to the
motor 15, so as to light the warming lamp 25 and rotate the
guide plate 5 and the transfer-sheet feeding rollers 6 and
7 in a reverse direction. Shown at 26 is a tray for housing
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the sheets 3 which failed to be stripped off the photo-
sensitive body.
Thus, the sheet 3 fed by the feed roller 4 is
subjected to image-transfer on the photosensitive body 1
and is subsequently stripped off the photosensitive body 1
by the air injected from the nozzle 22, so as to be trans-
ferred to a fixing station tnot shown) by the transfer-
sheet feeding device 23. If the sheet 3 fails to be strip-
ped, the follower 24a contacts the end of the sheet 3.
This operates the switch 24b for lighting the warning lamp
25, moving the guide plate 5 to the position as indicated
by the dotted line in Figure 1 as well as for rotating the
transfer-sheet feeding rollers 6 and 7 in a reverse direc-
tion At this time, the end of the sheet 3 is still in
position between the transfer-sheet feeding rollers 6 and
7 and therefore the sheet 3 is fed in a reverse direction
~y the reversing transfer-sheet feeding rollers 6 and 7,
stripped off the photosensitive body 1 and fed along the
guide plate 5 into the tray26.
The aforesaid guide plate 5 may alternatively
be moved in a vertical direction as shown in Figure 3.
Furthermore, in the embodiment shown, the switch
24b of the detector 24 is provided for reversing the
rollers 6 and 7. However, the operator of copying machine
may push the button for reversing said rollers upon the
lighting of the warning lamp 25, so that the reversal of
the rollers 6 and 7 and the guide plate 5 can be manually
accomplished.
As is apparent from the foregoing description,
upon the signal of the detector which is provided for
detecting the failure in sheet-stripping, rollers for
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feeding transfer-sheets are rotated in a reverse direction
so that a sheet is stripped off a photosensitive body and
the need for removing a sheet from a photosensitive.body
by hand is eliminated, thereby removing a sheet from a
photosensitive body easily in a short time. A further ad-
vantage is that even small-sized s'heets can be removed with
no need to remove a photosensitive body from a copying
machine. Therefore, the chance of photosensitive body
damage is minimized.
While the invention has been described with
reference to the structure disclosed, it is not confined to
the details set forth, but is intended to cover.such modi-
fications or changes as may come within the scope of the
following claims.
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