Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2000-07-27
2001-11-06
Royer, William J. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
Reexamination Certificate
active
06314256
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119 to Japanese patent application no. 11-212416, filed on Jul. 27, 1999, which application is herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention generally relates to image forming apparatus, such as copying machines, facsimile machines, printers and copying/facsimile/printing machines, and more particularly, to a device for preventing a fixing unit, provided within the image forming apparatus to fix a toner image transferred on a sheet onto the sheet, from inadvertently falling off of the apparatus.
Discussion of the Background
FIG. 1
is a schematic drawing illustrating a construction of a conventional printer for explaining a method of removing a fixing unit from a main body of the printer. Reference numeral
1
denotes the main body of the printer, reference numeral
2
denotes a sheet cassette, and reference numeral
3
denotes an electrophotographic image forming unit, which includes a photoconductor
4
. Reference numeral
5
denotes the fixing unit, which includes a heating roller
6
and a pressing roller
7
. The fixing unit
5
fixes a toner image, which has been transferred by the electrophotographic image forming unit
3
onto a recording sheet P by applying heat and pressure. Reference numeral
8
denotes a conveying path for the recording sheet P and reference numeral
9
denotes a discharging roller for discharging the recording sheet P after a fixing operation has been accomplished thereon to a discharged sheet tray
10
. Reference numeral
111
denotes an openable and closable cover that opens and closes to uncover and cover, respectively, a front side of the conveying path
8
and the fixing unit
5
(the right side in FIG.
1
).
The fixing unit
5
is detachably provided inside of the main body
1
of the printer so that the fixing unit
5
can be detached from the main body
1
, for example, for replacement with a new one. At an upper front part of the fixing unit
5
, a fixing unit supporting lever
12
and a pressure releasing lever
13
are provided side by side. The fixing unit supporting lever
12
is depressed to release a support of the fixing unit
5
in the main body
1
when removing the fixing unit
5
from the main body
1
for replacement, for example, and the pressure releasing lever
13
is depressed to release an applying pressure of the pressing roller
7
when removing a recording sheet P which has become jammed at a nip between the heating roller
6
and the pressing roller
7
.
The cover
11
is supported by an axis
14
at a bottom part of the cover
11
so as to be rotatable relative to the main body
1
. The cover
11
is opened to uncover the inside of the main body
1
when replacing the fixing unit
5
or when removing a recording sheet P which has become jammed at the conveying path
8
or in the fixing unit
5
. Under normal conditions, the cover
11
is closed to cover the fixing unit supporting lever
12
and the pressure releasing lever
13
, and the front side of the conveying path
8
and the fixing unit
5
as well.
When replacing the fixing unit
5
, the user first opens the cover
11
to uncover the front side of the main body
1
, depresses the fixing unit supporting lever
12
, and then draws out the fixing unit
5
. When removing a recording sheet P which has become jammed at the nip between the heating roller
6
and the pressing roller
7
of the fixing unit
5
, the user likewise opens the cover
11
to uncover the front side of the main body
1
, and then depresses the pressure releasing lever
13
to release the pressure of the pressing roller
7
for facilitating the clearance of the jammed recording sheet P.
However, in the above-described conventional printer, the fixing unit supporting lever
12
, which is used when replacing the fixing unit
5
, and the pressure releasing lever
13
, which is used when removing a jammed recording sheet P at the nip between the heating roller
6
and the pressing roller
7
, are arranged in close proximity to each other. Further, both the fixing unit supporting lever
12
and the pressure releasing lever
13
are operated by depressing operations which closely resemble each other. Therefore, the user tends to erroneously operate the fixing unit supporting lever
12
, not the pressure releasing lever
13
, for removing a jammed recording sheet P. Further, the user often inadvertently touches the fixing unit supporting lever
12
while operating the pressure releasing lever
13
.
SUMMARY OF THE INVENTION
The present invention has been made in view of and addresses the above-discussed and other problems.
Preferred embodiments of the present invention provide a novel image forming apparatus in which a fixing unit is prevented from falling off of the apparatus by an erroneous or inadvertent operation by the user and thereby the safeness of the apparatus is enhanced.
A preferred embodiment of the present invention provides an image forming apparatus including a fixing unit, that is detachably provided in the apparatus to fix a toner image transferred on a sheet onto the sheet, and a fixing unit falling off preventing device, to prevent the fixing unit from falling off the apparatus. The fixing unit falling off preventing device includes a first fixing unit supporting member and a second fixing unit supporting member that both support the fixing unit at a predetermined position within the apparatus. The first fixing unit supporting member releases the support of the fixing unit upon being depressed, and the second fixing unit supporting member releases the support of the fixing unit upon being rotated in a predetermined direction.
The image forming apparatus may further include a cover that opens and closes relative to the apparatus to uncover and cover, respectively, the fixing unit, and the second fixing unit supporting member may include a closure obstructing part that abuts against the cover, when the second fixing unit supporting member is not supporting the fixing unit, so as to prevent the cover from moving to a position to be closed.
According to the present invention, the fixing unit falling off preventing device may further include a return device for returning the second fixing unit supporting member to a position to support the fixing unit after releasing the support of the fixing unit.
Another preferred embodiment of the present invention provides an image forming apparatus including a fixing unit, that is detachably provided in the apparatus to fix a toner image transferred on a sheet onto the sheet, and that includes a case having a knob at a part thereof, and a fixing unit falling off preventing device, to prevent the fixing unit from falling off the apparatus. The fixing unit falling off preventing device includes a first fixing unit supporting member and a second fixing unit supporting member that both support the fixing unit at a predetermined position within the apparatus. The first fixing unit supporting member releases the support of the fixing unit upon being depressed. The second fixing unit supporting member has a knob part, which opposes the knob of the case of the fixing unit in a vicinity thereof, and which releases the support of the fixing unit by being moved in a predetermined direction while being held at the knob part thereof.
The fixing unit falling off preventing device may further include a return device for returning the third fixing unit supporting device to a position to support the fixing unit after releasing the support of the fixing unit.
Another preferred embodiment of the present invention provides an image forming apparatus including a fixing unit, that is detachably provided in the apparatus to fix a toner image transferred on a sheet onto the sheet, and a fixing unit falling off preventing device to prevent the fixing unit from falling off of the apparatus. The fixing unit falling off preventing device includes a first fixing unit supporting member, that supports the fixing unit at a predeter
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
Royer William J.
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