JP3301804B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder for pressurizing paper stored in a paper storage cassette in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, when paper stored in a paper storage cassette is fed under pressure by a paper feed roller or the like, the paper size is reduced so that problems such as poor paper feed and double feed do not occur. At the same time, it was necessary for the pressure to change according to the paper size.

[0003]

However, when changing the paper size, it is necessary to replace the paper storage cassette or replace it with a separately prepared elastic member for pressurizing, for example, a spring. .

There is also a method of fixing the paper side and making the pressing force constant at the paper feeding roller side. However, since the paper feeding position is made constant and the pressing force is changed, a mechanism for changing the pressing force becomes complicated. However, there is a disadvantage that not only the reliability is lowered but also the cost is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned problems by simplifying the construction, facilitating the manufacture, saving space, setting a pressing force suitable for each paper size, and setting a large number of paper sizes. An object of the present invention is to provide a sheet feeding device capable of feeding sheets.

[0006]

In order to achieve the above object, the present invention relates to a paper storage cassette provided in an image forming apparatus for feeding stored paper by a paper feed roller.
A pressure member that presses the paper against the paper feed roller, a slide shaft that rotates in conjunction with the pressure member and is slidable in the axial direction, and has a plurality of protrusions; A plurality of pressure arms interlocked with a shaft, and a plurality of pressurizing elastic members connected to one end of the pressure arm and applying a required pressing force to the slide shaft are provided. A sheet feeding device comprising a pressing elastic member switching device capable of switching with the pressing elastic member.

Further, according to one aspect of the present invention, the elastic member for pressing is set so that the length of the elastic member when the elastic member is switched is substantially free.

[0008]

By adopting the paper feeder of the present invention, a paper feed roller is provided with a pressurizing member for pressing the paper, and is rotated in conjunction with the pressurizing member so as to be slidable in the axial direction so that a plurality of protrusions can be formed. A plurality of pressurizing arms which are interlocked with the slide shaft by engaging with the projections, and are provided at one end of the pressurizing arm to apply a required pressurizing force to the slide shaft. A pressure spring switching device that is provided with a pressure elastic member and that can be switched to an arbitrary pressure spring by sliding the slide shaft has a simple configuration, is easy to manufacture, is space-saving, and is compatible with each paper size. The pressing force is set, and a large number of paper sizes can be fed.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment of a sheet feeding apparatus according to the present invention. In the drawing, a paper storage cassette 1 is provided with a pressing plate 5 which is a pressing member for pressing a middle plate 3 on which a paper is placed, and a pressing member integrally connected to the pressing plate 5 by a fixing screw 7. A shaft 9 is provided. In the elastic member switching device for pressing, in this embodiment, the spring switching device 11 for pressing, the slide shaft 13 is slidable in the axial direction and is connected to the pressing shaft 9 via the joint 15 and is rotated.

As shown in FIG. 2, the slide shaft 13 is provided with a plurality of projections 17, which are three spring pins in this embodiment.
a, 17b, 17c) and four pressing arms 19 (19a, 19a,
b, 19c, 19d).

At this time, one of the spring pins 17
When the book is engaged with the groove 18 of the pressing arm 19, the other two spring pins 17 are arranged so as not to engage with the pressing arm 19.

The pressing arm 19 (19a, 19a)
Pressing springs 21 (21a, 21b, 21c, 21d) are respectively connected to the arm ends of the b, 19c, 19d). Further, a rotation stopper 23 for preventing the rotation of the pressure arm 19 (19a, 19b, 19c, 19d) is provided in the tensioning direction of the pressure spring 21.
Pressing arm stopper 25 whose axial position is regulated
Is provided.

Further, as shown in FIG. 4, the auxiliary spring 27 (FIG. 1) is provided to secure a necessary force for lifting the intermediate plate 5 to the position C.

As shown in FIG. 3 (A), the pressurizing spring switching device 11 configured as described above
The pressing arm 19a is engaged with the pressing arm 19a by the spring pin 17a, and is engaged by sliding of the slide shaft 13, as shown in FIGS. 3 (B), (C) and (D).
b, 19c and 19d change.

FIG. 4 is a view for explaining the operation of the pressurizing spring switching device in the paper storage cassette. In the figure, for example, when the pressing arm 19a is engaged with the slide shaft 13 and the pressing of the middle plate 3 is released by another means not shown, the middle plate 3 is at the position A, and the pressing arm 19a is The length L1 is the length dimension of the pressure spring 21a when the pressure is released. At this time, the other pressure arms 19b, 19
c and 19d are at the C 'position.

When the paper is set and pressurized, the paper is pressed against the paper feed roller 29 by the pressurizing spring 21a of the pressurizing arm 19a, so that the paper can be fed. When the paper is fed until the paper runs out, the middle plate 3 and the pressing arm 19a move to the positions B and B ', respectively, and the length L2 is the length of the pressing spring 21a at the time of pressing without paper. .

At this time, since the pressure arm 19a does not move to the position C 'of the other pressure arms 19b, 19c and 19d, the slide shaft 13 slides during use to cause the other pressure arms 19b, 19c and 19d to move. There is no risk of engaging with 19d.

Next, in the case of switching the pressurizing spring, if the sheet storage cassette 1 is pressurized without being set in the image forming apparatus main body, the pressurizing arm 1
9a moves to the position C 'of the pressing arm stopper 25 by the spring force of the pressing spring 21a, and at the same time, the middle plate 3 moves to the C position. When the pressing arm 19a is at the position C ', since the pressing spring 21a is set at the free length or near the free length L3, the pressing arm 19a is pulled in the direction of the B' position by the weight of the intermediate plate 3.

Therefore, in this embodiment, the auxiliary spring 27 (FIG. 1) secures the necessary force for lifting the middle plate 3 to the position C, and at the same time, the stopper prevents the middle plate 3 from going beyond the position C. (Not shown) is provided, but may be fixed to the C position by hand instead of the auxiliary spring 27.

In this manner, the pressing arms 19a, 19a
b, 19c and 19d are at the same C 'position and the pressing springs 21a, 21b, 21c and 21d are at or near the free length L3 and no force is applied to the slide shaft 13. The sliding of the slide shaft 13 can be performed smoothly.

If the spring length is a free length or slightly longer at the position C, the pressing arms 19a, 1
9b, 19c and 19d are fixed, but when they are slightly shorter than the free length, the pressing arms 19a, 19b, 19c,
19d, the pressure arms 19a, 19
The fitting portions of b, 19c, and 19d are allowed to have room to cope with angular play.

As described above, one paper storage cassette 1
Accordingly, it is easy to set a pressing force suitable for a large number of paper sizes, and it is possible to feed a large number of paper sizes in a small space.

The present invention is not limited to the above embodiment, but can be embodied in other modes by making appropriate design changes.

[0025]

As is apparent from the above description, the paper feeder of the present invention has a paper feed roller provided with a pressure member for pressing the paper, and rotates in conjunction with this pressure member to rotate the shaft. A slide shaft having a plurality of protrusions slidable in the direction, and a pressurizing arm interlocked with the slide shaft by engagement with the protrusions, and connected to one end of the pressurizing arm to apply a required load to the slide shaft. A plurality of pressurizing springs for applying pressure are provided, and the pressurizing spring switching device capable of switching to an arbitrary pressurizing spring by sliding the slide shaft effectively solves the problems of the prior art and has a simple configuration. so,
It is easy to manufacture, space-saving, sets a pressing force suitable for each paper size, and makes it possible to feed a large number of paper sizes.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a sheet feeding device according to the present invention.

FIG. 2 is a schematic configuration diagram of a spring switching device of FIG. 1;

3A and 3B are explanatory diagrams of a switching operation of the spring switching device of FIG. 2, wherein FIG. 3A shows a case of switching a first pressure arm, FIG. 3B shows a case of switching a second pressure arm, and FIG. In the case of pressure arm switching, (D) is a case of fourth pressure arm switching.

FIG. 4 is an explanatory diagram illustrating an operation of a spring switching device in a sheet storage cassette.

[Explanation of symbols]

 Reference Signs List 1 paper storage cassette 9 pressurizing shaft 11 pressurizing spring switching device 13 slide shaft 15 joint 19, 19a, 19b, 19c, 19d pressurizing arm 21, 21a, 21b, 21c, 21d pressurizing spring 27 auxiliary spring 29 paper feed roller

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihito Nagayama 6-3-3 Shimorenjaku, Mitaka City, Tokyo Copier Corporation (72) Inventor Yasunori Maeda 6-3-3 Shimorenjaku, Mitaka City, Tokyo Inside Peer Co., Ltd. (72) Kazuhiro Nishimura 6-3-3 Shimorenjaku, Mitaka City, Tokyo Copia Corporation (72) Inventor Shiaki Teshima 6-3-3 Shimorenjaku, Mitaka City, Tokyo Copier Corporation (72) Inventor Hidetaka Fukiharu 6-3-3 Shimorenjaku, Mitaka City, Tokyo Copier Corporation (72) Inventor Iwao Kawamura 6-3-3 Shimorenjaku, Mitaka City, Tokyo Copier Corporation (56) References JP-A-4-280741 (JP, A) JP-A 62-100940 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 1/00-3/68

Claims (2)

(57) [Claims] 1. A sheet feeding device for feeding stored sheets by a sheet feeding roller provided in an image forming apparatus, comprising: an intermediate plate for bringing the sheet into contact with the sheet feeding roller; A pressing member for pressing, and a pressing shaft fixed to the pressing member and rotating in a predetermined direction
One When a slide shaft which rotates together with the pressurized pressure axis is connected to the pressurized pressure bearings, either alternatively to projection provided on said slide shaft
More but a plurality of pressure arm which engages, coupled to the plurality of pressure arm each end, the pressure arm engaged with the projection, to impart pressure in the direction of lifting the intermediate plate A pressure elastic member, wherein the slide shaft slides in the axial direction , and the plurality of pressure arms are engaged with the protrusions.
One is to move the slide shaft in conjunction with the rotation of the slide shaft.
The slide shaft is slid in the axial direction thereof so that the protrusion
By selectively engaging the pressure arm with
A sheet feeding device comprising a pressurizing elastic member switching device for switching a pressing force of a middle plate . 2. A method for stopping rotation of the pressure arm.
A pressure arm stopper; wherein the plurality of pressure elastic members are configured such that the pressure arm is stopped by the pressure arm stopper;
2. The sheet feeding device according to claim 1, wherein the sheet feeding device is set so as to have a substantially free length when the sheet feeding is performed.