JPH05238572A - Automatic paper feeder - Google Patents

Abstract

PURPOSE:To prevent nonfeed due to that a point end of paper is bitten into a paper separating plate for preventing a double feed. CONSTITUTION:A low friction sheet 11, overlapped with a side of a paper feed roller 6 of a paper separating plate 7 provided to bring the point end part into contact with a peripheral surface of the paper feed roller 6 by stopping the point end part blocked of a paper holder, is provided and formed of a base part 12 and an introducing part 13 integrally provided with this base part 12 to bring the point end part into contact with the peripheral surface of the paper feed roller 6. Further, the tapered introducing part 13 is provided respectively in both side parts in a width direction of the base part 12, to respectively cover both side edges in the width direction of the base part 12 by a pair of these introducing parts 13 and also to expose the paper separating plate 7 between a pair of these introducing parts 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for feeding sheets to a document reading section or a printing section of a facsimile or a copying machine, and more particularly to a plurality of stacked sheets which are separated and fed one by one. The present invention relates to an automatic paper feeder suitable for printing.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show the structure of a conventional automatic paper feeder. In these drawings, reference numeral 1 is a paper transport guide made of synthetic resin, and an upper guide plate 2 and a lower guide plate 3 are provided.
Connected with. The middle portion of the paper transport guide 1 is bent, and the lower guide plate 3 in this portion is provided with a lower opening 4 which is long in the width direction of the paper, and the upper guide plate 2 also has a similar upper opening 5. It is provided. A boundary between the bent middle portion of the paper transport guide 1 forms a paper holder 1a at the paper carry-in side, and a paper carry-out portion 1b connected to a printing unit (not shown) at a portion opposite to the holder 1a. ..

The sheet holder 1a is supplied with sheets of single-cut sheets, and a plurality of sheets A having a predetermined capacity are stacked and accommodated. A paper feed roller 6 which is driven to rotate counterclockwise in FIG. 8 by a pulse motor or the like (not shown) is disposed below the paper transport guide 1. This roller 6 has a roller portion 6b made of synthetic rubber fixed to the outer periphery of a rotary shaft 6a, and only one roller portion 6b is provided corresponding to the widthwise central portion of the paper A to be supplied. There is. A part of the roller portion 6b passes through the lower opening 4 and enters the bent portion of the sheet conveyance guide 1. Therefore, the paper feed roller 6 is provided at the front end of the paper holder 1a on the paper conveyance direction side.

The upper guide plate 2 has a mounting wall 2a (see FIG. 8) extending above the upper opening 5 thereof.
The sheet separating plate 7 is fixed by a rivet 8.
As shown in FIG. 7, the sheet separating plate 7 has a quadrangular shape having a width smaller than the length of the roller portion 6b of the sheet feeding roller 6, and has a tip portion (lower end portion in the figure) inserted into the sheet conveying guide 1. Is provided so as to contact the peripheral surface of the roller portion 6b of the paper feed roller 6 and block the leading end of the paper holder 1a. The sheet separating plate 7 is made of silicone rubber, and the friction between the sheet A and the sheet feeding roller 6 is larger than the friction between the sheet separating plate 7 and the sheet A due to the material of the roller portion 6b.

A leaf spring 9 as an urging member is sandwiched between the sheet separating plate 7 and the mounting wall 2a. The width of the spring 9 is substantially the same as the width of the paper separating plate 7,
Is fixed to the mounting wall 2a by the rivet 8. The leaf spring 9 faces the upper opening 5, and the spring force of the leaf spring 9 causes the leading end of the sheet separating plate 7 to move to the sheet feeding roller 6.
Is pressed against the peripheral surface of the roller portion 6b.

A flexible low friction sheet 10 made of tetrafluoroethylene is stacked on the surface of the sheet separating plate 7 on the side of the sheet feeding roller 6. The friction between the low-friction sheet 10 and the paper A is the smallest. The sheet 10 is used to smoothly guide the leading ends of the stacked sheets A to the contact portion between the sheet feeding roller 6 and the sheet separating plate 7, and has the same width as the sheet separating plate 7 as shown in FIG. An introduction portion 10b having a triangular shape is integrally provided at the lower end of the base portion 10a having a width to form a pentagonal shape as a whole. Therefore, in the low-friction sheet 10, the length of each portion along the direction orthogonal to the width direction gradually increases from both ends in the width direction to the central portion.

The low-friction sheet 10 is fixed by the rivets 8 and its introduction portion 10b is provided between the peripheral surface of the roller portion 6b of the paper feed roller 6 and the leading end portion of the paper separating plate 7 in contact therewith. It is inserted toward. Note that FIG.
In FIG. 5, reference numeral B is a tangent line (parallel to the rotation axis of the paper feed roller 6) passing through the contact point b between the paper feed roller 6 and the low friction sheet 10 shown in FIG.

In the automatic paper feeder having such a structure, the papers A stacked and accommodated in the paper holder 1a are supplied.
Are separated one by one according to the rotation of the paper feed roller 6 and are supplied to the printing unit or the like through the paper unloading unit 1b.

That is, the paper A1 whose front end is in contact with the peripheral surface of the roller portion 6b of the paper feed roller 6 is located between the outer periphery of the paper feed roller 6 and the contact portion between the paper separation plate 7 due to friction with the paper feed roller 6. The sheet A2, which is fed in and overlaps the sheet A1 at that time, also receives a moving force in the direction of the sheet separating plate 7 due to the friction between these sheets A1 and A2. However, since the leading edge of the sheet A2 hits the sheet separating plate 7 exposed on both sides of the introduction portion 10b and further movement is hindered, only the sheet A1 contacting the sheet feeding roller 6 is finally separated from the other sheet groups. The paper is separated and passed between the paper feed roller 6 and the paper separating plate 7 and is carried out.

By the way, the low-friction sheet 10 is the base 1
When it is formed by only 0a, it is difficult to dispose the tip edge of the base portion 10a just in alignment with the contact b because the dimensional variation of each component has a great influence.
If the leading end of the base portion 10a is hung over the paper feed roller 6 too much, a double feed that simultaneously conveys two sheets at a time is likely to occur, and conversely, the leading end of the base portion 10a is fed to the paper feed roller 6. If the paper is not applied, the introduction of the paper is not smooth, and the paper is likely to slip and cause non-feed in a state where the paper is not conveyed. Therefore, as described above, since the low-friction sheet 10 has the triangular introduction portion 10b, the friction of the leading end of the sheet A with respect to the sheet separation plate 7 is gradually increased, and the sheet A that contacts the sheet feeding roller 6 is gradually increased. The leading end of the sheet can be smoothly guided to the contact portion between the sheet feeding roller 6 and the sheet separating plate 7, and therefore the arrangement of the low friction sheet 10 and the sheet feeding roller 6 can be easily managed.

[0011]

However, in the structure of the conventional low-friction sheet 10, as shown in FIG. 9, when the leading end of the sheet A is in contact with the introducing section 10b, the introducing section 10b of the sheet A and The front end portions (shown by the dimension range E) in contact with the sheet separating plate 7 try to move while being bent along the sheet separating plate 7 and the low-friction sheet 10 so as to follow the outer periphery of the sheet feeding roller 6. However, the paper separating plate 7 and the low friction sheet 1 having a width shorter than the length of the paper feeding roller 6
The leading edge of the paper A that is out of 0 (indicated by the dimension range F) is
Attempts to go straight by contact with the paper feed roller 6.

Therefore, when the thickness of the sheet A is large, such as when the sheet A is thick, the sheet A is separated from the sheet separating plate 7 at the initial stage of sheet feeding.
Bend on both sides in the width direction. Then, the bent portions bite into both side edges of the sheet separating plate 7 exposed on both sides of the introducing portion 10a, and as a result,
There was a problem that non-feed may be caused.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic paper feeder which can prevent non-feeding caused by the leading edge of a paper biting into a paper separating plate for preventing double feed.

[0014]

In order to achieve the above object, an automatic sheet feeder according to the present invention is provided so that the leading end of the sheet feeding roller is brought into contact with the peripheral surface of the sheet feeding roller to block the leading end of the sheet holder. A low-friction sheet that is superposed on the sheet separating roller side of the sheet separating plate, the sheet including a base portion and an introducing portion integrally provided on the base portion and having a tip portion in contact with the peripheral surface of the sheet feeding roller. And the introduction portions are provided on both side portions in the width direction of the base portion to cover both side edges in the width direction of the base portion with the pair of introduction portions, respectively, and the sheet separation is performed between the pair of introduction portions. It is an exposed plate.

[0015]

In the above structure, the pair of introducing portions provided on both sides in the width direction of the low-friction sheet cover both side edges in the width direction of the sheet separating plate, and the outer periphery of the sheet feeding roller and the leading end of the sheet separating plate. The leading end of the sheet is smoothly guided to the contact portion, and the exposed portion of the sheet separating plate exposed between the introducing portions separates the sheets stacked and accommodated in the sheet holder. In the paper feeding operation, even if the paper conveyed in contact with the paper feeding roller is bent at the widthwise edges of the paper separating plate and the low-friction sheet at the beginning of the paper feeding, the bent portion separates the paper. The pair of introducing portions covering the both widthwise side edges of the sheet separating plate respectively prevent contact with both widthwise side edges of the plate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the description, the same components as those of the conventional automatic sheet feeder described with reference to FIGS. 4 to 6 are designated by the same reference numerals, and the description thereof will be omitted. Only a configuration different from the conventional example will be described. explain.

This embodiment is different from the conventional example in the structure of the low friction sheet 11 made of tetrafluoroethylene. Specifically, as shown in FIGS. 1 and 2, the low friction sheet 11
Is formed of a quadrangular base portion 12 and a pair of introduction portions 13 integrally provided at one end in the direction orthogonal to the width direction. The width of the base 12 is the same as the width of the sheet separating plate 7, but may be larger than that. The sheet A is provided on both side portions of the base portion 12 in the width direction toward the contact portion between the sheet feeding roller 6 and the sheet separating plate 7.
The pair of introducing portions 13 for smoothly guiding the are formed in, for example, a substantially right triangle shape. One side 13a sandwiching the right angle of these introducing portions 13 is linearly continuous with both side edges of the base portion 12 in the width direction and covers both side edges of the base portion 12, respectively. The slanted sides 13b of the pair of introduction portions 13 are opposed to each other. By having such a pair of introduction portions 13, the low-friction sheet 11 has the length of each portion along the direction orthogonal to the width direction thereof that both side edges in the width direction are long and the center portion in the width direction is long. It has a short structure, and the paper separating plate 7 is exposed between the pair of insertion portions 13.

In the automatic sheet feeder having the low-friction sheet 10 having such a configuration, when the sheet feeding roller 6 is rotated, the sheet feeding roller 6 out of the sheets A stacked and accommodated in the sheet holder 1a. The sheet A1 whose front end is in contact with the peripheral surface of the section 6b is fed between the outer circumference of the roller 6 and the contact portion of the sheet separating plate 7 by friction with the sheet feeding roller 6, and the sheet A1 is overlapped with the sheet A1. A2 is also the paper A
1 and A2 receive a moving force in the direction of the sheet separating plate 7 due to mutual friction. However, the sheet A2 has a pair of leading portions 1 at the leading end.
Since the exposed portion of the sheet separating plate 7 exposed between the sheets 3 is prevented from moving further, only the sheet A1 in contact with the sheet feeding roller 6 is separated from the other sheet group, and the sheet feeding roller 6 and the sheet are separated. It passes between the separation plate 7.

That is, in this way, the paper holder 1a
The sheets A stacked and accommodated therein are not double-fed with the rotation of the sheet feeding roller 6, but are separated one by one and are supplied to the printing unit or the like through the sheet unloading unit 1b.

When the sheet A fed as described above is strong, the leading end portions of the low friction sheet 11 which are in contact with the pair of the introducing portions 13 and the sheet separating plate 7 (see FIG. 2).
The portion indicated by the middle dimension E) tries to move while being bent along the paper separating plate 7 and the low-friction sheet 10 so as to follow the outer periphery of the paper feed roller 6, and is longer than the length of the paper feed roller 6. The leading end portion (the portion within the range indicated by the dimension F in FIG. 2) of the sheet A that has left the sheet separating plate 7 and the low-friction sheet 10 having a short width tries to go straight by contact with the sheet feeding roller 6. Therefore, at the beginning of feeding, the sheet A is bent along the both side edges of the sheet separating plate 7 in the width direction.

However, the low-friction sheet 11 having the same width as the sheet separating plate 7 has a pair of introducing portions 13 on both sides in the width direction of the sheet separating plate 7 so as to cover both side edges of the separating plate 7. Even when the front end of the sheet A is bent, the introduction section 13 prevents the front section of the sheet A from biting into both side edges of the sheet separating plate 7 in the width direction. It can be guided to the contact portion between the peripheral surface of 6 and the tip of the sheet separating plate 7.

In this manner, the pair of introducing portions 13 of the low-friction sheet 11 can prevent the leading edge of the sheet fed by the rotation of the sheet feeding roller 6 from biting into the sheet separating plate 7 which prevents double feeding. .. Therefore, non-feeding of the sheet A1 in contact with the sheet feeding roller 6 is prevented, and the sheet A1 at the lowermost position stored in the sheet holder 1a can be sequentially separated and conveyed.

The present invention is not limited to the above embodiment. For example, as shown in FIG. 4, the slanted sides 13b of the pair of introduction portions 13 of the low-friction sheet 11 may form an arc, and as shown in FIG. 5, the pair of slanted sides 13b are substantially V-shaped.
The introduction portions 13 may be provided so as to form a letter shape and be continuous with each other. Further, as shown in FIG. 6, the introduction portion 13 of the low-friction sheet 11 may have a strip shape instead of the triangular shape.

[0024]

As described above in detail, the automatic sheet feeding device of the present invention is provided with a sheet separating plate provided with the leading end portion contacting the peripheral surface of the sheet feeding roller and blocking the leading end portion of the sheet holder. A low-friction sheet that is stacked on the side of the paper feed roller is provided, and this sheet is formed from a base portion and an introduction portion integrally provided on the base portion and having a leading end portion in contact with the peripheral surface of the paper feed roller, and Introducing portions are provided on both side portions in the width direction of the base portion, respectively, and both side edges in the width direction of the base portion are respectively covered by the pair of introducing portions, and the paper separating plate is exposed between the pair of introducing portions. With the configuration, at the initial stage of sheet feeding, the pair of introducing portions can prevent the leading edge of the sheet from biting into the both widthwise edges of the sheet separating plate. Therefore, non-feeding can be prevented, and the stacked sheets can be reliably held one by one. Separated and fed There is an effect that kill.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a main part of an automatic paper feeder according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a low-friction sheet of the automatic sheet feeder according to the same embodiment.

FIG. 3 is a cross-sectional view showing the configuration of the entire automatic paper feeder according to the same embodiment.

FIG. 4 is a plan view showing another configuration of the low friction sheet.

FIG. 5 is a plan view showing another configuration of the low friction sheet.

FIG. 6 is a plan view showing another configuration of the low friction sheet.

FIG. 7 is a perspective view showing a configuration of a main part of an automatic sheet feeding device according to a conventional example.

FIG. 8 is a cross-sectional view showing the configuration of the entire automatic paper feeding device according to the conventional example.

FIG. 9 is a plan view showing a configuration of a low-friction sheet of the automatic sheet feeding device according to the conventional example.

[Explanation of symbols]

1a ... Paper holder, 6 ... Paper feed roller, 7 ... Paper separating plate,
9 ... Leaf spring (biasing body), 11 ... Low friction sheet, 12 ... Base part, 13 ... Introduction part.

Claims (1)

[Claims] 1. A paper holder to which a paper is supplied, a paper feed roller that is provided at the tip of the paper holder and is driven to rotate, and a paper feed roller having a width smaller than the length of the paper feed roller and a circumference of the paper feed roller. A sheet separating plate which is provided so as to bring the leading end into contact with the surface to block the leading end of the sheet holder, and a biasing body which presses the leading end of the sheet separating plate against the peripheral surface of the sheet feeding roller, A low-friction sheet having a base portion overlapped with the sheet separating plate on the paper feed roller side, and an introduction portion integrally provided on the base portion and having a leading end portion in contact with the peripheral surface of the paper feed roller. In the automatic sheet feeding device described above, the low-friction sheet introducing portions are provided on both side portions in the width direction of the base portion, and the pair of introducing portions covers both side edges in the width direction of the base portion, and the pair of introducing portions is introduced. Expose the paper separation plate between the Automatic feeding device, characterized in that the.