Sheet feeding or delivering – Feeding – Multiple supplies
Reexamination Certificate
2001-09-14
2003-10-21
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
Multiple supplies
C271S009010
Reexamination Certificate
active
06634634
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus for recording an image on a sheet-like record medium such as a sheet cut to a predetermined size in an image forming section thereof, and a sheet feed apparatus for delivering the sheet-like record medium to the image forming section of the image forming apparatus.
2. Description of the Related Art
As an image forming apparatus such as a printer and a facsimile, there are used image forming apparatus of various types such as an electrophotographic type, an ink jet type, and a thermal transfer type. In most of them, in the image forming section thereof, an image such as a character or a figure is formed on a sheet-like record medium such as a sheet cut to a predetermined size.
For example, in case of the ink jet type and thermal transfer type, an image is formed on a sheet in accordance with a digital signal.
Also, in case of the electrophotographic type and electrostatic recording type, by applying a toner to an electrostatic latent image on an image carrier, a toner image is formed; and, after then, the toner image is transferred and fixed onto a sheet.
In case of the sheet onto which the image is to be applied, generally, many units of such sheets are piled up on top of another and stored in a sheet feed apparatus which is disposed within the image forming apparatus and the sheets are sequentially supplied one by one.
The sheets to be stored in the sheet feed apparatus require proper replenishment and, in order to be able to facilitate the replenishment of the sheet, there is used a sheet tray formed in a cassette which can be mounted onto and removed from the main body of the sheet feed apparatus; and, actually, the sheets are supplied to and stored in the sheet tray.
In case of such sheet tray, there is a case where only a single sheet tray is disposed in an image forming apparatus but; in many cases, in order that sheets of different sizes can be selected for application of images, two or more cassettes or sheet trays are disposed.
Also, in some of image forming apparatus, as an annex thereto, there is disposed a hand-operated tray which is convenient for arbitrary use of sheets of various sizes and various kinds.
As an ordinary image forming apparatus including a mechanism which takes out sheets one by one from a sheet tray or a hand-operated tray and feeds them sequentially to a position where an image is to be formed, there is known an image forming apparatus having a structure shown in FIG.
10
.
That is, in an image forming apparatus
200
shown in
FIG. 10
, two sheet trays of a cassette type
204
,
206
are disposed downwardly of a hand-operated tray
202
.
In the deeper side of the hand-operated tray
202
, there are disposed a semilunar roller
210
and a handling member
212
. The semilunar roller
210
, in operation, can be contacted with an upper surface of the upper-most sheet P of sheets stored in the hand-operated tray
202
and, when rotated, can send out the upper-most sheet P toward a registration roller
214
.
The handling member
212
is formed of material having large friction and is used to separate the lower-side sheets P, which are delivered together with the uppermost sheet P, from the upper-most sheet P.
The sheet teed apparatus of a type using the semilunar roller
210
is advantageous in that it is relatively simple in structure and is easy to control.
However, in the above-mentioned image forming apparatus
200
, there are found the following problems.
In a structure where the hand-operated tray
202
is disposed in the upper-most stage and the sheet trays
204
,
206
of a removable cassette type are disposed downwardly of the hand-operated tray
202
, a sheet delivery route, which extends from sheet feed rollers
216
,
218
for feeding sheets P in the sheet trays
204
,
206
, respectively, up to the registration roller
214
, is long: that is, there is a problem that height dimensions of the sheet feed apparatus and thus the image forming apparatus are large.
Also, in the case of the semilunar roller being used as the sheet feed roller, since there is a limit on the sheet delivery quantity of the semilunar roller, in an intermediate portion of the sheet delivery route between the semilunar roller and registration roller, there must be disposed a turn roller which is used to deliver the sheet up to the registration roller. This increases the number of parts and complicates the structure of the sheet feed apparatus and thus the image forming apparatus.
By the way, instead of provision of the turn roller, as in the image forming apparatus
200
, in case where the sheet feed rollers
216
,
218
for feeding out the sheets P of the cassette-type sheet trays
204
,
206
are composed of round rollers, a mechanism (such as an electromagnetic clutch) for controlling the delivery quantity of the sheets P must be connected to the sheet feed rollers
216
,
218
. This increases the number of parts as well as complicates the structure and control of the sheet feed apparatus and thus the image forming apparatus further.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the above drawbacks found in the sheet feed apparatus according to the related art as well as in the image forming apparatus according to the related art. Accordingly, it is an object of the invention to provide an image forming apparatus which can control the height dimensions of a sheet feed apparatus down to a low level, can minimize the number of parts and thus can simplify the structure thereof.
According to a first aspect of the invention, there is provided A sheet feed apparatus comprising:
a first sheet tray;
a second sheet trays disposed in a lower direction with respect to the first sheet tray;
a first sheet feed roller contacting with top one of sheets piled up to be stored in the first sheet tray, the first sheet feed roller adapted to feed the sheets;
a first handling member adapted to cooperate with the first sheet feed roller to prevent a plurality of the sheets stored in the first sheet tray from being fed together;
a second sheet feed roller contacting with top one of sheets piled up to be stored in the second sheet tray, the second sheet feed roller adapted to feed the sheets stored in the second sheet tray;
a second handling member adapted to cooperate with the second sheet feed roller to prevent a plurality of the sheets stored in the second sheet tray from being fed together; and
a registration roller adapted to nip the sheets fed out from the first sheet tray and the sheets fed out from the second sheet tray to deliver the both sheets to an image forming section disposed in an upper direction with respect to the first sheet feed roller,
wherein the registration roller is disposed between a first tangent line passing through a handling portion between the first sheet feed roller and the first handling member, and a second tangent line passing through a handling portion between the second sheet feed roller and the second handling member.
Next, description will be given of an operation of the sheet feed apparatus according to the first aspect of the invention.
Firstly, the first sheet feed roller is contacted with the upper-most sheet of the sheets piled up and stored in the first sheet tray to feed the upper-most sheet to the registration roller side. In this operation, the first handling member cooperates with the first sheet feed roller to prevent two or more units of the sheets from being fed together. The first handling member is used to prevent the sheets arranged downwardly of the upper-most sheet from being fed together with the upper-most sheet. Therefore, the first handling member, naturally, is disposed downwardly of the first sheet feed roller and the sheet delivery direction downstream side of the first handling member is inclined obliquely upwardly.
Next, the second sheet feed roller is contacted with the sheets piled up and stored in the second sheet tray to thereby feed the sheets to the registration roller side. In this o
Fuji 'Xerox Co., Ltd.
Joerger Kaitlin
Oliff & Berridg,e PLC
Walsh Donald P.
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