Radiant energy – Photocells; circuits and apparatus – Photocell controlled circuit
Reexamination Certificate
1999-01-19
2001-01-23
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controlled circuit
C250S239000, C399S033000
Reexamination Certificate
active
06177666
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to image forming apparatuses such as copiers and printers provided with a plurality of sheet transport routes for transporting a sheet after an image fixation along a certain transport route of the plurality of transport routes and a route changer mechanism for selectively changing the transport route.
A construction of an image forming apparatus as shown in
FIG. 3
is known in which a sheet after an image transfer is transported along a certain transport route of a plurality of transport routes and discharged outside a main body of the apparatus by an operation of a route changer mechanism.
FIG. 3
is a partially enlarged diagram of the construction. In
FIG. 3
,
302
is an imaging unit of the apparatus. The imaging unit
302
includes a photoreceptor
300
and a transfer roller
301
. An image transfer is performed by the imaging unit
302
.
Specifically, an electrostatic latent image is formed on an outer circumference of the photoreceptor
300
based on an image read from a document. By electrically attracting charged toner onto the latent image, the latent image is developed into a toner image on the surface of the photoreceptor
300
. The toner image on the photoreceptor surface is electrically attracted to a copy sheet transported to the photoreceptor
300
due to a transfer voltage applied between the photoreceptor
300
and the transfer roller
301
to transfer the toner image onto the copy sheet. In this way, the toner image is transferred onto the sheet.
Fixing rollers
303
,
303
are arranged downstream of the imaging unit
302
with respect to a sheet transport direction (indicated by the upward-directing arrow in FIG.
3
). After passing the imaging unit
302
, the sheet has the toner image fixed thereon by the fixing rollers
303
,
303
by a thermal treatment. The fixing rollers
303
,
303
are accommodated in a frame
303
a
composed of a resin or a metallic material together with a heater as a one-piece unit. The construction of the one-piece unit contributes to improvement of heat transmission efficiency.
A transport route formed downstream of the fixing rollers
303
,
303
is branched into a transport route
305
communicating with a discharge port
307
and a transport route
304
communicating with a discharge port
308
opposite to the discharge port
307
. A sheet after an image fixation is selectively transported either along the transport route
304
or the transport route
305
by the route changer mechanism.
Specifically, a switching member
306
as the route changer mechanism is provided at the junction of the transport routes
304
,
305
. The switching member
306
is pivotable about a pivot point to selectively guide a sheet after an image fixation to the transport route
304
and the transport route
305
. When the switching member
306
is set in a state shown by the solid line in
FIG. 3
, the sheet is transported toward the transport route
305
while guided along the bold solid line P in FIG.
3
and discharged onto a discharge tray
313
via the discharge port
307
. In this case, the sheet is discharged onto the discharge tray
313
with the side carrying an image facing downward.
On the other hand, when the switching member
306
is set in a state shown by the dashed line in
FIG. 3
, the sheet is transported toward the transport route
304
and discharged onto a finisher (not shown) or a discharge tray (not shown) with the side carrying an image facing upward.
Also, when the switching member
306
is set in the dashed-line state in
FIG. 3
to guide a sheet along the transport route
304
, the transport routes
304
,
305
are communicated to each other. Accordingly, in this state, the transport routes
304
,
305
functions as a switchback route to guide a sheet toward the discharge port
308
along the phantom line P′ in
FIG. 3
by performing the following operations.
Specifically, first, the switching member
306
is set in the solid-line state to temporarily transport a sheet toward the discharge port
307
. When a tail end of the sheet reaches a certain position between a discharge roller pair
309
,
309
provided near the discharge port
307
and the switching member
306
, the discharge roller
309
is driven in a reverse direction. At this time, changing the posture of the switching member
306
to the dashed-line state allows the sheet to be transported toward the discharge port
304
along the transport routes
305
,
304
.
More specifically, in the above state when the switchback route is provided by the transport routes
304
,
305
, connecting the transport route
304
to an access route (not shown) via the discharge port
308
and the imaging unit
302
enables a double sided image transfer by feeding the sheet after a first image transfer again to the imaging unit
302
while utilizing the switchback route and the access route. The access route connecting the transport route
304
and the imaging unit
302
may be provided by mounting an external device on a side wall of the apparatus main body, e.g., a side wall of the apparatus on the same side as a cover
310
in which the discharge port
308
is formed.
The cover
310
is openably mounted on the side wall of the apparatus, and opening the cover
310
allows the transport route
304
accessible to outside of the apparatus. Likewise, a cover
311
is openably mounted on a top portion of the apparatus near the discharge port
307
. Opening the cover
311
allows the transport route
305
to be accessible to outside of the apparatus. Opening the cover
310
(
311
) enables removing a jammed sheet in the transport route
304
(
305
).
In the above apparatus, in case of removing a jammed sheet in the transport route
304
(
305
), it is likely that the switching member
306
may be broken or damaged due to a pulling force exerted thereto. In such a case, it is required to replace the broken or damaged switching member
306
with a new one.
Since the route changer mechanism including the switching member
306
is directly mounted on the apparatus main body, a service person must take out the broken or damaged switching member
306
by inserting his/her hand inside the apparatus main body. As shown in
FIG. 3
, however, around the switching member
306
there are densely arranged a number of parts such as discharge rollers
312
,
312
for feeding a sheet to the transport route
304
and the fixing rollers
303
,
303
in a certain limited space, which makes a replacement cumbersome. In particular, it is highly likely that a new switching member
306
is mounted to the apparatus main body at a position deviated from the previous mounting position with respect to the fixing rollers
303
,
303
. Mounting at the deviated position obstructs securing the transport route for a sheet which has passed between the fixing rollers
303
,
303
and is being transported toward the transport route
304
(
305
), thereby increasing the possibility of jamming.
There is an idea of providing a sufficient space in the apparatus for facilitating the replacement of the switching member
306
in order to improve serviceability of the apparatus. This idea, however, leads to production of a large sized apparatus and not favorable in a practical sense.
Accordingly, there is demanded an improved arrangement of the apparatus with improved serviceability of the route changer mechanism such as easy replacement of a switching member to eliminate a sheet transport failure due to a positional displacement of the route changer mechanism relative to the fixing rollers while effectively suppressing production of a large sized apparatus.
SUMMARY OF THE INVENTION
In view thereof, it is an object of the present invention to provide an image forming apparatus of a small size having an improved serviceability.
To fulfill the above object, an image forming apparatus, according to an aspect of this invention, comprises: a main body; a frame removably mounted on the main body; fixing means mounted on the frame for fixing a toner image onto a sheet trans
Akedo Shuichi
Hanano Susumu
Ishida Naoyuki
Oda Kenji
Yamamoto Shinji
Jordan and Hamburg LLP
Kyocera Mita Corporation
Le Que T.
LandOfFree
Image forming apparatus having a removable route changer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image forming apparatus having a removable route changer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image forming apparatus having a removable route changer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541093