Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1999-12-08
2001-12-11
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S813000, C198S814000, C198S832000
Reexamination Certificate
active
06328155
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a transfer belt unit which is mounted on a full color copying machine, a color printer and the like.
An image forming apparatus such as a full color copying machine, a color printer or the like has a process unit provided with four image forming portions (yellow, magenta, cyan and black) for forming the respective color images in parallel, and a transfer belt for conveying a paper through these four image forming portions. The transfer belt is tensioned around a pair of rollers which are arranged apart from each other, arranged below the process unit and rolls in contact with a photosensitive drum in each of the image forming portions.
Further, four transfer rollers are arranged in an inner side of the transfer belt in a positional relationship opposing to each of the photosensitive drum. Each of the transfer rollers functions so as to apply a high bias voltage from the inner side of the transfer belt, supply a high voltage to a paper adhered and held on the transfer belt in an electrostatic manner and conveyed, and transfer a toner image with each of the colors formed on a surface of the photosensitive drum on the paper in an overlapping manner.
In general, a drive roller and a driven roller around which the transfer belt is wound are rotatably mounted to a frame of the image forming apparatus. That is, the transfer belt is assembled in the image forming apparatus in a fixed manner. Further, a power supply portion for supplying a high voltage from a side of an apparatus main body is connected to each of the transfer rollers.
Accordingly, at a time of replacing the transfer belt or the transfer roller due to a service life, at first the process unit including four image forming portions is taken out from the image forming apparatus by a service operator. Thereafter, the transfer belt is taken out from the apparatus, a connection between the transfer roller and the power supply portion is cancelled so as to take out the transfer roller from the apparatus, and a new transfer belt and a new transfer roller are mounted to the apparatus.
Further, in this kind of image forming apparatus, in the case that a jamming of the paper is generated between the process unit and the transfer belt, the process unit is taken out from the apparatus or the process unit is slightly tilted and moved apart from the transfer belt so as to form a slight space between the transfer belt and the process unit, thereby removing the paper.
However, in the conventional image forming apparatus mentioned above, in the case of replacing the transfer belt and the transfer roller by the new ones, it is necessary to take out the transfer belt from the apparatus and take out the connection between each of the power supply portions of the transfer rollers so as to take out the transfer rollers from the apparatus after temporarily taking out the process unit from the apparatus, so that there is a problem that it is troublesome to replace the transfer belt and the transfer rollers. Accordingly, the user can not replace the transfer belt and the transfer rollers and the replacing operation requires much load for the service operator. Further, as mentioned above, since much time is required for replacing the transfer belt and the transfer rollers, there is a problem that a time for which the apparatus is stopped for the replacing operation is increased, so that the rate of operation of the apparatus is reduced.
Further, in the conventional image forming apparatus mentioned above, in the case of treating the jamming of the paper clogged between the process unit and the transfer belt, in the apparatus of a type which is rotated upward around one end of the process unit so as to be tilted, it is impossible to sufficiently secure a treating space in the upstream side or the downstream side of the transfer belt, so that it is troublesome to remove the paper.
BRIEF SUMMARY OF THE INVENTION
The present invention is made by taking the points mentioned above into consideration, and an object thereof is to provide a transfer belt unit which can easily attach and detach a transfer belt with respect to a main body of an image forming apparatus.
In order to achieve the object mentioned above, according to the present invention, there is provided a transfer belt unit including:
a first roller to which a driving force is transmitted under a state of being mounted within a main body of an image forming apparatus from a side of the main body;
a second roller arranged apart from the first roller;
a transfer belt wound around the first and second rollers and tensioned so as to run in an endless manner;
the first and second rollers and the transfer belt forming a unit and structured so as to be attached to and detached from the main body.
According to the invention mentioned above, since the first roller, the second roller and the transfer belt are made the unit and structured so as to be attached to and detached from the main body of the image forming apparatus, it is possible to easily replace the transfer belt due to a service life.
Further, according to the present invention, there is provided a transfer belt unit detachably mounted to an image forming apparatus for forming an image on a medium via a plurality of image forming portions, including:
a first roller to which a driving force is transmitted under a state of mounting the transfer belt unit to a main body of the image forming apparatus from a side of the main body;
a second roller arranged apart from the first roller;
a transfer belt wound around the first and second rollers and tensioned so as to run in an endless manner, holding the medium and conveying the medium through the plurality of image forming portions;
a plurality of transfer rollers arranged inside the transfer belt in correspondence to the plurality of image forming portions;
the first and second rollers, the transfer belt and the plurality of transfer rollers being integrally formed.
Further, according to the present invention, there is provided a detachable mechanism for a transfer belt unit which is provided in a side of a main body of an image forming apparatus for detachably mounting the transfer belt unit to a predetermined position within the main body,
the transfer belt unit integrally having first and second rollers apart from each other, a transfer belt wound around the first and second rollers and tensioned so as to run in an endless manner, a transfer roller provided inside the transfer belt and a pair of frames rotatably supporting both ends of the first and second rollers;
the detachable mechanism comprising:
a drive mechanism connected to the first roller when mounting the transfer belt unit within the main body so as to rotate the first roller; and
a lift-up mechanism for lifting up the pair of frames of the transfer belt unit inserted into the main body and connected to the drive mechanism so as to set the transfer belt unit to the predetermined position.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
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Hiruta Koichi
Nakatomi Yoshitsugu
Omura Ken
Todome Tsuyoshi
Ellis Christopher P.
Foley & Lardner
Sharma Rashmi
Toshiba Tec Kabushiki Kaisha
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