Typewriting machines – Sheet or web – For feeding plural record media concurrently or selectively
Reexamination Certificate
2000-11-27
2004-03-23
Hirshfield, Andrew H. (Department: 2854)
Typewriting machines
Sheet or web
For feeding plural record media concurrently or selectively
C400S607000, C400S624000, C400S693000, C271S009110, C271S009130
Reexamination Certificate
active
06709177
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus for recording images on a sheet-shaped recording medium such as paper cut to a given size, and a paper feeding apparatus for piling up image recording sheets of paper on one another to store the image recording sheets of paper therein and also for feeding out the image recording sheets of paper one by one therefrom.
2. Description of the Related Art
An image forming apparatus such as a copying machine, a printer and a facsimile includes various types such as an electrophotographic type, an ink jet type and a heat transfer type; and, in most of them, images such as letters and pictures are formed on paper which is cut to a given size.
For example, in the ink jet type and heat transfer type, the images are formed on the paper in accordance with digital signals. Also, in the electrophotographic type and electrostatic recording type, toners are applied onto electrostatic latent images carried on an image carrier element to thereby form toner images there, and the toner images are then transferred to and fixed on the paper.
The sheets of paper, on which images are to be formed, are generally piled up on top of each other and stored in a paper feeding apparatus disposed within the image forming apparatus and the thus stored sheets of paper are then supplied sequentially one by one from the paper feeding apparatus.
The sheets of paper to be stored within the paper feeding apparatus must be replenished properly. In order to be able to facilitate this paper replenishment, there is used a paper tray which can be mounted onto and removed from the main body of the image forming apparatus; that is, the sheets of paper are replenished into the paper tray and stored in the paper tray. In some cases, only one paper tray is disposed for one image forming apparatus; and, in most cases, two or more cassettes (paper trays) are used in combination in order to be able to select sheets of paper of different sizes and apply images onto the selected paper. And, in some other cases, in combination with the two or more paper trays, there is disposed a hand-held tray which is convenient when various sheets of paper having different sizes are used arbitrarily.
A mechanism, which is used to take out the sheets of paper one by one from the paper tray or hand-held tray and feed them one by one to a position where images can be given, is generally structured as shown in
FIGS. 8A and 8B
.
Specifically,
FIG. 8A
shows a structure of a type in which a function to feed out the sheets of paper and a function to prevent two or more sheets of paper from being fed together in a superimposed manner are divided from each other; and, this type of structure comprises a paper feed roller
101
which can be contacted with the upper surface of paper
104
stored within a paper tray and can be rotated to thereby feed out the top-layer sheet of paper from the paper tray, a handling roller
102
for delivering the thus fed-out paper while preventing two or more sheets of paper from being fed together in a superimposed manner, and a handling member (pad)
103
which is formed of material showing large friction and can be contacted with the handling roller
102
to thereby separate superimposedly-fed sheets of paper from each other.
In this mechanism, the paper
104
, which has been fed out from the paper tray by the paper feed roller
101
, is passed through the contact position between the handling roller
102
and handling member
103
and is then delivered to an image applying position. And, in case where two or more sheets of paper are taken out from the paper tray while they are superimposed on top of each other, at the time when the lower surface of the paper is contacted with the handling member
103
, the friction between the paper
104
and handling member
103
becomes larger than the friction between the superimposed sheets of paper, so that the sheet of paper on the lower side is separated from the sheet of paper on the upper side and thus only the sheet of paper on the upper side is delivered to the image applying position.
Now,
FIG. 8B
shows a structure of another type in which a paper feed roller has a function to feed out the sheets of paper from the paper tray and a function to prevent two or more sheets of paper from being fed together in a superimposed manner. In this type of structure, a paper feed roller
111
is contacted with the upper surface of paper
113
stored in a paper tray and, at the same time, a handling member
112
is contacted with the rotation-direction downstream side of the paper feed roller In this type of mechanism, similarly to the above type of mechanism, the paper can be fed out from the paper tray and, while the handling member
112
prevents two or more sheets of paper from being fed together in a superimposed manner, only a sheet of paper can be delivered to the image applying position. In this type, since the contact portion of the paper
113
and the contact portion of the handling member
112
are set on the peripheral surface of the paper feed roller
111
, the diameter of the paper feed roller
111
must be set rather large. In spite of this, however, there can be obtained an advantage that the paper feed mechanism can be simplified in structure and thus the manufacturing cost thereof can be reduced.
On the other hand, the paper tray is classified into two types according to the removing directions thereof, while the two types of paper trays are selectively used depending on the types of the paper feed mechanisms. That is, when the paper tray is set, the paper feed mechanism is situated in the vicinity of the end portion of the paper tray and feeds out the sheets of paper substantially in the horizontal direction from the end portion of the paper tray. In this case, there are two types of paper trays: specifically, in one type, the paper tray can be removed from an image forming apparatus by pulling the paper tray in the same direction as a direction in which the paper is fed out from the paper tray; and, in the other type, the paper tray can be removed by pulling the same in the opposite direction to the above-mentioned paper feed-out direction.
An image forming apparatus of a type that a paper tray is removed in the same direction as the paper feed-out direction is disclosed in, for example, JP-A-4-247469 and JP-B-7-40169.
Also, an image forming apparatus of a type that a paper tray is removed in the opposite direction to the paper feed-out direction has such a structure as shown in FIG.
9
.
In this apparatus, paper trays
121
,
122
can be mounted into and removed from the apparatus through the front surface thereof; and, paper fed out from the reapportion of the apparatus is passed through a delivery passage
123
and is then delivered to a portion
124
where an image is transferred.
As a mechanism for operating a handling member when removing a paper tray from the main body of the image forming apparatus, there are two different types. That is, in one type of mechanism, the handling member is supported on the apparatus main body side and thus it is separated from the paper tray; and, even in case where the paper tray is pulled out from the apparatus main body, the handling member is still left within the apparatus. On the other hand, in the other type of mechanism, the handling member is mounted on the paper tray and thus the handling member is taken out from the apparatus main body simultaneously when the paper tray is pulled out.
Also, as a mechanism for bringing sheets of paper piled up within a form tray into contact with a paper feed roller, there are available various types.
The sheets of paper to be stored within the paper tray varies in quantity as they are replenished or consumed but the upper surface of the top-layer sheet of paper must be always contacted with the paper feed roller. In view of this, there are employed many mechanisms structured such that the paper feed roller or the piled-up sheets of paper can be energized by springs or oth
Fuji 'Xerox Co., Ltd.
Hirshfield Andrew H.
Morgan & Lewis & Bockius, LLP
Williams Kevin D.
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