Sheet feeding or delivering – Feeding – Multiple supplies
Reexamination Certificate
1999-01-19
2001-07-31
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
Multiple supplies
C271S301000, C271S065000
Reexamination Certificate
active
06267368
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, such as a copying machine or a facsimile machine, having a multiple image forming capability to perform a double-sided image transfer or combined image transfer operation, for instance, as well as to a paper return device which is added to an image forming apparatus to give it multiple image forming capability.
In one previous approach to realizing the multiple image forming capability in a copying machine, one side of each sheet of a document is successively copied, individual sheets of copying paper, each carrying a reproduced image on one side, are stacked as if in a stock, and then the other side of each sheet of the document is successively copied. This approach is known as a stock method. In another previous approach known as a non-stock method, two sides of each sheet of a document are copied in succession on two sides of each sheet of copying paper before copying on a succeeding sheet of copying paper.
In one known example of a non-stock type copying machine, a sheet of paper carrying an image reproduced on one side in an image forming section provided inside a main body of the copying machine is ejected through a paper output port, which opens to the outside of the main body of the copying machine, the ejected sheet is transferred to a paper return slot formed in the main body of the copying machine by a reversible paper transport unit which is detachably fitted to the main body, and the sheet reentering from the paper return slot is fed again to the image forming section through a re-feeding path. In this construction, it is possible to provide a paper re-feed mechanism for double-sided copying operation in the form of the reversible paper transport unit which is detachably fitted to the main body of the copying machine. This means that the aforementioned construction makes it possible to provide a double-sided copying mechanism as an optional unit and thereby increase the ease of maintenance.
Today's copying machines are mostly of a type that accommodates paper trays in their main bodies. The majority of this type of copying machines also have manual feed trays for loading sheets of paper to be fed directly from outside their main bodies to permit manual paper feed as is the case with the aforementioned conventional copying machines.
As will be noted from the above discussion, a conventional copying machine having the aforementioned construction usually has two paper paths for feeding paper to an image forming section from outside a main body of the copying machine. These are a re-feeding path for feeding the paper transferred by a reversible paper transport unit and a manual feeding path for feeding individual sheets of paper loaded on a manual feed tray. A problem of this conventional structure is that the provision of more than one paper path for similar use leads to an inefficient use of available space and an increase in equipment cost.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a paper return device and an image forming apparatus which make it possible to achieve improved space utilization efficiency and cost reduction by combining multiple paper paths for feeding paper from outside a main body of the apparatus to an image forming section provided inside the main body into a single path.
In one aspect of the invention, an image forming apparatus comprises a paper return device which is detachably fitted to a main body of the image forming apparatus having a paper feeding port for feeding paper from outside, a paper transport mechanism for transporting the paper from the paper feeding port to an image forming unit and a paper output port ejecting the paper with an image formed by the image forming unit to the outside. The paper return device comprises a paper return guideway which connects the paper output port of the image forming apparatus to its paper feeding port when the paper return device is fitted to the image forming apparatus. The image forming apparatus also comprises a paper supply unit for re-feeding the paper ejected from the paper output port back to the paper feeding port through the paper return guideway.
When performing a double-sided copying operation using an image forming apparatus provided with the aforementioned paper return device, a sheet of paper ejected from the paper output port carrying an image on one side only is returned to the paper feeding port through the paper return guideway and fed again into the apparatus through the paper feeding port. Accordingly, it is not necessary to provide a dedicated manual feeding path in the apparatus for re-feeding the paper. This makes it possible to combine conventionally separate paper paths from outside of the apparatus to its internal image forming unit into a single path, and eventually achieve improved space utilization efficiency and cost reduction.
In another aspect of the invention, an image forming apparatus comprises an image forming unit provided inside a main body of the image forming apparatus for forming an image on paper, a paper transport mechanism for transporting the paper from a paper feeding port formed in the main body of the image forming apparatus opening to its outside to the image forming unit, a paper ejector for ejecting the paper carrying the image formed by the image forming unit to the outside of the main body of the image forming apparatus through a paper output port formed in the main body opening to its outside, and a paper return device having a paper return guideway which connects the paper output port to the paper feeding port to feed the paper ejected from the paper output port back to the paper feeding port through the paper return guideway.
When performing a double-sided copying operation using the image forming apparatus thus constructed, a sheet of paper ejected from the paper output port formed in the main body of the apparatus carrying an image on one side only is returned to the paper feeding port through the paper return guideway and fed again into the apparatus through the paper feeding port. Accordingly, it is not necessary to provide a dedicated manual feeding path in the apparatus for re-feeding the paper. This makes it possible to combine conventionally separate paper paths from outside the main body of the apparatus to its internal image forming unit into a single path, and eventually achieve improved space utilization efficiency and cost reduction.
These and other objects, features and advantages of the invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.
REFERENCES:
patent: 4968016 (1990-11-01), Koyama
patent: 5056768 (1991-10-01), Koyama
patent: 5615872 (1997-04-01), Mochimaru
patent: 5957450 (1999-09-01), Kida et al.
patent: 0086326 (1986-05-01), None
patent: 363134435 (1988-06-01), None
patent: 401308323 (1989-12-01), None
Hanano Susumu
Itoh Yukihiro
Masaki Eijiro
Mihara Takashi
Oda Kenji
Jordan and Hamburg LLP
Kyocera Mita Corporation
Schlak Daniel K
Walsh Donald P.
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