JPH09142685A - Automatic paper feed device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent double feed without enlarging the device. SOLUTION: A paper feed roller 9 is driven to rotate anticlockwise by a drive motor, and a friction member 12 is pressed in contact with the circumferential face of the paper feed roller 9 by a presser spring 11. The friction force between a document P and the friction member 12 is larger than the friction force among documents P, and the friction force between the document P and the paper feed roller is set further larger. The friction member 12 is formed into a stepped shape in side view, and the lower end of the stepped part 12a is at the A-point, the lower end of the extreme end 12b is at the B-point, respectively pressed in contact with the paper feed roller 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic paper feeder which is adopted in printers, facsimile machines and the like, and which feeds out sheets one by one.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing a schematic construction of a conventional automatic paper feeder applied to a facsimile machine. This will be described with reference to FIG. 1. Reference numeral 1 denotes a facsimile machine as a whole, and includes a lower case 2 on which a drive motor or a control board (not shown) is mounted, and a lower case 2 which is openably and closably supported. The cover 3 is provided. Reference numeral 5 denotes a guide plate which has a substantially flat shape similar to the surface area of the cover 3 and which is formed in a substantially flat plate shape. The guide plate 5 is fixed to a frame (not shown) in the lower case 2 so as to be horizontal, A document transport path 6 having a document insertion port 7 is formed together with the upper end surface of the document transport path 2.

Reference numeral 8 denotes a stacker mounted on the lower case 2 for placing the original P on the extension line of the original conveying path 6. Reference numeral 9 denotes a paper feed roller whose upper portion faces the inside of the document transport path 6, and is rotationally driven counterclockwise in the drawing by a drive motor (not shown). 10 is this paper feeding roller 9
The window 10a notched in the guide plate 5 at a position corresponding to
Is a cut-and-raised portion cut and raised from the upper edge of the window 10. 11 is a pressing portion 11a with its tip bent in a dogleg shape.
A pressing spring 20 is formed, and a friction member 20 is formed in a rectangular parallelepiped shape. The pressing spring 11 and the friction member 20 are overlapped with each other and fastened together with the cut-and-raised portion 10a by the screw 13 at the base end portion thereof, and the pressing force of the pressing spring 11 causes the pressing portion 11a to move the distal end portion of the friction member 20 together. It is in pressure contact with point A of the paper feed roller 9.

Reference numeral 14 denotes a contact sensor which is an optical reading head which extends in the width direction of the document with the reading section located on the transport path surface of the document transport path 6, and 15 which is in contact with the contact sensor 14 and which is not shown in the drawing. It is a platen roller that is driven to rotate clockwise in the figure by a motor. Here, if the friction coefficient between the paper feed roller 9 and the original P is μ1, the friction coefficient between the friction member 20 and the original P is μ2, and the friction coefficient between the originals P is μ3, then μ1>μ2> The material of the paper feed roller 9 and the friction member 20 is selected with respect to the material of the original P so as to be .mu.3.

In such a structure, when a plurality of originals P are stacked on the stacker 8, the originals P slide down from the original insertion opening 7 into the original conveyance path 6 by their own weight, and are separated between the paper feed roller 9 and the friction member 20. Sandwiched between. Of the plurality of originals P sandwiched, the lowermost (first) original comes into contact with the paper feed roller 9 and the friction member 20, and since μ1> μ2 as described above, the paper feed roller 9 is rotated. Following it, it is conveyed to the contact sensor 14 side. On the other hand, since the second original is μ2> μ3, the friction member 2 is used even though the first original is conveyed.
Transport is blocked by 0. In this way, the plurality of documents P are fed to the contact sensor 14 one by one, and the content of the document is optically read by the contact sensor 14.

[0006]

However, in the above-described conventional automatic paper feeder, μ2 <μ due to environmental changes due to static electricity generated between documents P and changes in humidity.
Therefore, the so-called double feeding phenomenon occurs in which the second original is fed following the first original. In order to prevent this, another friction member is provided on the peripheral surface of the paper feed roller 9 to prevent double feeding, but there is a problem that the device becomes large.

Therefore, the present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an automatic sheet feeding apparatus which prevents double feeding without increasing the size of the apparatus. is there.

[0008]

In order to achieve this object, an automatic sheet feeding device according to the present invention comprises a sheet feeding roller which is rotationally driven and a friction member which is pressed against the peripheral surface of the sheet feeding roller. An automatic paper feeding device that is equipped with a friction member and feeds paper fed by rotation of a paper feeding roller one by one,
By forming the friction member in a stepped shape in a side view, a plurality of pressure contact portions of the friction member to the paper feed roller are provided. Therefore, the document passes through a plurality of pressure contact portions between the friction member and the rollers, so that the occurrence of double feeding is further reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of a facsimile apparatus to which an automatic sheet feeder according to the present invention is applied,
FIG. 2 is a partially cutaway plan view, and FIG. 3 is a side view of an essential part for explaining the operation. In these figures, the same or equivalent members described in the prior art shown in FIG. 4 described above are designated by the same reference numerals, and detailed description thereof will be omitted. Reference numeral 16 is a dial button provided on the cover 3, and 17 is a handset arranged on the side surface of the lower case 2.

A feature of the present invention is that the friction member 1
The point is that the tip of No. 2 is formed stepwise in a side view. With this structure, the friction member 12 is pressed against the peripheral surface of the sheet feeding roller 9 by the pressing portion 11a of the pressing spring 11.
, The lower end of the stepped portion 12a and the lower end of the tip end 12b are in contact with each other at two points A and B of the sheet feeding roller 9.

Therefore, in such a configuration,
In FIG. 3A, the plurality of originals P sandwiched between the paper feed roller 9 and the friction member 12 are rotated by the paper feed roller 9 in the counterclockwise direction.
Separated from the first and subsequent documents. At this time, as shown in FIG. 7B, when the second original is also fed and passed through the point A, the second original is changed to the first original by the friction member 12 at the point B. Separated from the manuscript.

That is, here, the second original not only contacts the lower end of the tip 12b of the friction member 12 at the point B but also contacts the lower end of the stepped portion 12a at the point A. Since the frictional force between the second original and the friction member 12 is much larger than the frictional force between the second original, double feeding is reliably prevented. In this way, double feeding is reliably prevented and one friction member 12
Since two pressing portions for pressing the peripheral surface of the sheet feeding roller 9 are provided, the size of the apparatus does not increase as compared with the case where two friction members 12 are provided as in the conventional case.

In this embodiment, the stepped portion 12a is 1
Although an example in which only one piece is provided is shown, it goes without saying that two or more pieces may be provided if necessary. Further, the friction member is formed of one member, but the two members may be overlapped so that the stepped portion 12a and the tip 12b are different members,
In this case, by selecting materials having different friction coefficients, it is possible to automatically feed various types of originals having different friction coefficients.

[0014]

As described above, according to the present invention, the paper feed roller which is rotationally driven and the friction member which is pressed against the peripheral surface of the paper feed roller are provided, and the paper is fed by the rotation of the paper feed roller. In an automatic paper feeding device that feeds sheets of paper by a friction member one by one, the friction member is formed in a step shape in a side view to provide a plurality of pressure contact portions of the friction member to the paper feeding roller. Therefore, double feeding of documents is prevented without increasing the size of the apparatus.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a facsimile device to which an automatic paper feeding device according to the present invention is applied.

FIG. 2 is a partially cutaway plan view showing a schematic configuration of a facsimile device to which an automatic paper feeding device according to the present invention is applied.

FIG. 3 is a side view of a main part for explaining the operation of the automatic sheet feeder according to the present invention.

FIG. 4 is a cross-sectional view showing a schematic configuration of a facsimile machine to which a conventional automatic paper feeder is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Facsimile apparatus, 6 ... Original conveyance path, 9 ... Paper feeding roller, 11 ... Pressing spring, 12 ... Friction member, 12a ... Step section,
12b ... Tip.

Claims (1)

[Claims] 1. An automatic feeding system, comprising: a sheet feeding roller that is driven to rotate; and a friction member that is brought into pressure contact with a peripheral surface of the sheet feeding roller. In the paper feeding device, the friction member is formed in a stepped shape in a side view, and a plurality of press contact portions of the friction member with the paper feeding roller are provided.