JPH09142673A - Paper sheet cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately perform stacking, receiving and guiding regardless of being inside or outside the range of the standard dimension of a paper sheet, in a paper sheet cassette of an image forming device. SOLUTION: A movable paper sheet guide 2 is connected to one end of a pickup roller shaft 5 through a link 3, and the other end of the pickup roller shaft 5 is connected to a gear 9 and a motor 10 through a joint. When paper sheets 6 are stacked and received in this paper sheet cassette, the movable paper sheet guide 2 can be moved so as to open, and hence the paper sheets 6 can be simply received regardless of being inside or outside the range of the standard dimension of the paper sheet. After stacking and receiving the paper sheets 6, the movable paper sheet guide 2 is closed, the pickup roller 4 is rotated by the drive motor 10, and the upper most paper sheet of the stacked and received paper sheets 6 is sent out. By reaction of driving force for sending out, force is applied to the link 3 and the movable paper sheet guide 2 in the closing direction, and hence the movable paper sheet guide 2 functions as a guide while pressing the side of the paper sheets 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, and more particularly to a paper cassette for supplying stacked and stored sheets to an image forming section.

[0002]

2. Description of the Related Art An image forming apparatus such as a printer is provided with a paper cassette in which sheets are stacked and stored, and the sheets are supplied one by one to an image forming section (Japanese Patent Application Laid-Open No. 3-27292).
No. 0). As shown in FIG. 6, the structure of the conventional paper cassette includes a fixed paper guide 1 for guiding the paper 6 in the feeding direction on one side of the stacked and stored papers 6, and a paper feeding guide on the other side of the paper 6 along the feeding direction. And a paper guide 2 having an interval slightly larger than the standard size of the paper 6 with respect to the fixed paper guide 1. The paper guide 2 includes a movable sub-guide 12 supported by a leaf spring 13.
The movable sub-guide 12 serves as a guide for the sheet 6 while suppressing the sheet 6 with a spring force.

Further, the paper cassette has an urging portion (not shown) for lifting the paper 6 from below and bringing the paper 6 into contact with the pickup roller 4, a driving motor 10 for rotating the pick-up roller 4, and a gear. 9 and a shaft 5 of the pickup roller 4.

The uppermost sheet of the sheet 6 lifted by the urging portion while being held on both sides by the fixed sheet guide 1 and the movable sub-guide 12 is sent out by the pickup roller 4 in the sending direction.

[0005]

However, in the conventional paper cassette, it is assumed that the paper is manufactured to the standard size, and the dimensional error of the stacked and stored paper is constant with respect to the standard size. If the amount is exceeded, there arises a problem that the paper cannot be stored or that the movable sub-guide cannot hold the paper. That is, if the paper is too large, the paper cannot be stored, and if the paper is too small, the movable sub-guide is not pressed against the paper and the guide ability is lost.

[0006] Even when sheets of standard dimensions are stored, the movable sub-guide 12 is biased in the sheet direction by the leaf springs 13. As a result, the distance between the fixed paper guide 1 and the movable sub-guide 12 becomes smaller than the standard size of the paper,
There is also a problem that it is difficult to stack and store sheets in a sheet cassette.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a paper cassette which can properly store and guide paper even when the standard size of the paper exceeds a certain amount, and can easily store paper of a standard size. And

[0008]

The present invention, which achieves the above objects, has the following features. (1) In a paper cassette for stacking and storing sheets and supplying the sheets to an image forming unit, a fixed sheet guide for guiding the sheets along a feeding direction;
A movable paper guide disposed at a position facing the fixed paper guide; and a link connecting the movable paper guide to one end of a shaft of a pickup roller for feeding the paper. (2) In the above (1), the other end of the shaft is connected to the power unit via a joint. (3) In (1) above, the joint is a universal joint. (4) In the above (1), the movable paper guide includes:
It is characterized by having a spring capable of adjusting the amount of protrusion.

In the state where the paper is not stored in which the paper is not pressed by the pickup roller, the movable paper guide can freely rotate via the shaft or the link of the pickup roller.
Sheets can be stacked and stored without hindrance, and after stacking and storing sheets, the sheet can be guided while being pressed by the movable sheet guide irrespective of whether the sheet is within or outside the standard size range due to the reaction force of sheet feeding by the pickup roller.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, embodiments of the present invention will be described. FIG. 1 is an overall perspective view of the paper cassette, and the same parts as those in FIG. 6 are denoted by the same reference numerals. That is, the fixed paper guide 1 is arranged on one side of the paper 6, and the movable paper guide 2 is arranged on the other side of the paper 6, and the pickup roller 4 for feeding the uppermost paper at the end of the paper 6 in the feeding direction.
A motor 10, a gear 9, and a shaft 5 for driving the pickup roller 4 are arranged.

When the sheets 6 are stacked and stored in the sheet cassette, the sheets 6 are stacked on a push-up plate 7, which is pushed up by a push-up spring 8, and the uppermost sheet is pressed against the pickup roller 4. Can be

In supplying the paper 6 to an image forming unit (not shown), the drive motor 10 is driven, and the pickup roller 4 is rotated via the gear 9 and the shaft 5 to feed the paper 6.

A movable paper guide 2 disposed at a distance from the fixed paper guide 1 by substantially the standard size of the paper.
, One end of a link 3 is attached rotatably in the horizontal direction, and the other end of the link 3 rotatably supports a shaft 5 of a pickup roller 4. A projecting piece 11 is provided at an intermediate portion of the link 3, and the projecting piece 11 is attached to the paper cassette as a fulcrum that allows the link 3 to rotate in the horizontal direction.

A joint 14 is provided at the other end of the shaft 5 whose one end is rotatably supported by the link 3. The joint 14 is formed as a universal joint as shown in FIGS. 3 and 4. The end of the shaft 5 is formed into a truncated pyramid shape 14a having a tapered shape. It is formed in a shape that fits in correspondence with the shape 14a. The rotation of the gear 9 is transmitted to the shaft 5, and the taper of the joint 14 connects the shaft 5 to the gear 9 so that the shaft 5 can be bent to a certain angle.

As a result, the shaft 5 and the link 3 connected to the shaft 5 and, consequently, the movable paper guide 2 rotate about the joint 14 as a fulcrum. However, the rotation of the link 3 causes the movable paper guide 2 to open and close in the width direction of the paper 6.

In this way, when the sheets 6 are stacked and stored in the sheet cassette, the movable sheet guide 2 can be moved so as to open, so that the sheets 6 can be easily stored regardless of whether they are within the standard size range of the sheets.

The joint 14 is not an essential component,
This may be omitted and the shaft 5 may be directly coupled to the gear 9. In that case, the shaft portion 5 is made to oscillate with the bearing portion (indicated by P in FIG. 2) of the fixed paper guide 1 as a fulcrum. However, the joint 14 is provided as in the above example, and the joint 14
Is used as a fulcrum, the moving amount of the movable guide 2 can be increased.

After the sheets 6 are stacked and stored, the movable sheet guide 2 is closed, and then the pickup roller 4 is rotated by the drive motor 10 to send out the uppermost sheet of the stacked and stored sheets 6. A force is applied to the link 3 and the movable paper guide 2 in the closing direction by the reaction force, whereby the movable paper guide 2 functions as a guide while pressing the side surface of the paper 6.

FIG. 5 is provided with a leaf spring 2a whose spring force can be adjusted in order to optimize the pressing force of the movable sheet guide 2 against the sheet 6 based on the reaction force of the pickup roller 4. That is, to support the leaf spring 2a partially penetrating the movable paper guide 2, and to adjust the amount of projection, the leaf spring 2a is used.
The base end of the leaf spring 2a is fixed to the movable paper guide 2 with a screw 2b, and the tapered member 2c is fitted to the leaf spring 2a.
This is to change the protrusion amount of a. In this case, the leaf spring 2a
The gap between the base end of the leaf spring 2a and the movable paper guide 2 is changed by providing an elongated hole in the one tapered member 2c to which the plate spring 2a is attached, and the amount of protrusion of the leaf spring 2a is changed. It should be noted that various other means can be considered for adjusting the amount of protrusion of the leaf spring 2a. Further, the leaf spring 2a is required to have a spring force that effectively acts on the sheet using the reaction force of the pickup roller 4 as a pressing force.

[0020]

As described above, according to the present invention,
Regardless of whether the paper is within the standard size range or not, the paper can easily be stacked and stored, and can be guided by pressing.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a paper cassette according to the present invention.

FIG. 2 is a plan view of a paper cassette.

FIG. 3 is an exploded view of a joint.

FIG. 4 is a sectional view of a joint.

FIG. 5 is a cross-sectional view of another example of the movable paper guide.

FIG. 6 is a plan view of a conventional example.

[Explanation of symbols]

 2 Movable paper guide 2a Leaf spring 3 Link 4 Pickup roller 5 Shaft 6 Paper 9 Gear 14 Joint 14a Pyramidal trapezoid shape

Claims (4)

[Claims] 1. A paper cassette that stacks and stores paper and supplies the paper to an image forming unit, and a fixed paper guide that guides the paper along a feeding direction and a fixed paper guide that sandwiches the paper and faces the fixed paper guide. A sheet cassette, comprising: a movable sheet guide disposed at a position; and a link connecting the movable sheet guide and one end of a shaft of a pickup roller for feeding the sheet. 2. The paper cassette according to claim 1, wherein the other end of the shaft is connected to a power unit via a joint. 3. The paper cassette according to claim 2, wherein the joint is a universal joint. 4. The paper cassette according to claim 1, wherein the movable paper guide is provided with a spring capable of adjusting a protrusion amount.