JPH1045261A - Automatic paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate sheets one by one without causing a feed failure or double feed by providing an elastic means deformable in the sheet feeding direction on a regulating member which makes contact with the top position of stacked sheets to press the stacked sheet to a feeding means, and regulates the tip part of the stacked sheet. SOLUTION: A sheet separating means 20 is arranged on the paper feeding directional side of a regulating member 1b having an elastic means 15 mounted thereon so as to surely separate the sheets delivered by a feed roller 7 one by one, and this means is formed of a carrying roller 21 and a separating roller 2 making contact with it. The stacked sheet pressed onto the feed roller 7 by the pressing means 10 is delivered by the drive of the feed roller 7, and separated into one piece through the elastic means 15 mounted on the regulating member 1b and the sheet separating means 20. The resulting sheet is guided into a printer 80 and carried to a printing part through carrying rollers 73, 74 provided within the printer 70.

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 mounted on a paper processing apparatus such as a printer, a copying machine, etc., for separating sheets stacked on a sheet stacking plate one by one and conveying the separated sheets to a sheet processing section. About.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 14, the paper loaded on the paper feed tray is pressed against the feed roller by the weight and the leading end of the loaded paper is regulated by the leading end regulating member, and the feed roller is driven to rotate. There is known an automatic sheet feeder for separating and feeding one sheet at a time from the lowermost sheet.

In this type of apparatus, when the friction coefficient between the feeding roller and the sheet is μ, the friction coefficient between the weight and the sheet is μ1, and the friction coefficient between the sheets is μ2, the sheets can be separated one by one. Thus, it is set so that μ>μ1> μ2.

[0004]

However, μ2 is not constant depending on the paper quality of the paper to be loaded. For example, in the case of postcards and envelopes, μ2 is larger than that of ordinary paper due to the rough surface of the paper. As a result, when a large number of such sheets are stacked, the frictional force acting between the sheets may be larger than the frictional force acting between the feeding roller and the sheets,
Non-feeding, double feeding, or the like in a state of being regulated by the leading end regulating member occurs. SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic sheet feeding apparatus capable of separating and feeding sheets one by one without causing non-feeding and double feeding even for sheets of different paper quality.

[0005]

In order to solve the above-mentioned problems, an automatic sheet feeder according to the present invention comprises a sheet stacking means for stacking sheets, and a sheet feeding means for feeding sheets sequentially from the lowest sheet among the stacked sheets. A feeding roller, a pressing unit that abuts on the top of the stacked sheets and presses the stacked sheets against the feeding unit, and a regulating member that regulates a leading end portion of the stacked sheets; And an elastic means capable of being deformed in the sheet feeding direction.

When the paper loaded on the paper loading means is fed out by the feed roller, the loaded paper is brought into contact with the regulating member by the feeding operation. The regulating member is provided with an elastic means, and the loaded paper is moved in the feeding direction by the elastic means being elastically deformed in the feeding direction. During this movement, the frictional force acting between the sheets is reduced. ,
The transition from the static friction force to a lower dynamic friction force. Usually, the kinetic frictional force acting between the sheets is smaller than the kinetic frictional force acting between the feeding roller and the sheet, so that one sheet can be separated without non-feeding or double feeding.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the automatic paper feeder according to the present invention will be described below. FIG. 1 is a partial cross-sectional side view showing a state in which an automatic paper feeder is mounted on a printer serving as a paper processing apparatus, and FIG. 2 is a plan view thereof.

The automatic paper feeder 1 is electrically and mechanically detachably mounted on a portion of the printer 70 where the manual feed tray 71 is provided. The frame 1a of the automatic sheet feeder 1 supports a rear end side of various sheets, and a mounting plate 3 is rotatably supported so as to stack and accommodate the sheets. A pair of side guides 5 are slidably provided in a direction perpendicular to the sheet feeding direction on the frame 1 a on the sheet feeding direction side of the mounting plate 3. Regulate both sides. As shown in FIG. 1, the paper stacked on the mounting plate 3
By its own weight, the frame 1 is moved through elastic means described later.
a and the regulating member 1b integral with the a.

The frame 1a supports a rotating shaft 7a driven by a driving source (not shown) and to which a feed roller 7 is fixed. Further, the frame 1 a is provided with a pressing unit 10 that comes into contact with the uppermost sheet of the sheets stacked on the mounting plate 3. This pressing means is provided so as to be displaceable with respect to the frame 1a so as to always contact the uppermost sheet irrespective of the stacked amount of sheets, and presses the lowermost sheet against the feed roller 7.

An elastic means 15 is attached to the regulating member 1b so that the leading end of the stacked sheets comes in contact with the regulating member 1b. The elastic means of the present embodiment is constituted by a rib-shaped sponge member, the thickness of which is set to about 4 mm,
Two places are provided at a predetermined interval in the width direction of the stacked sheets. In this case, as shown in FIG. 1, the lower end of the elastic member 15 is
Is preferably configured to protrude from the lower end of the sheet and elastically bend in the feeding direction as the sheet is conveyed. Further, it is preferable that the portion of the elastic means 15 to which the loaded paper abuts has a surface which is easily slid so that the paper does not swell. For example, a member such as a film 18 is attached.

A sheet separating means 20 is arranged on the side of the regulating member 1b to which the elastic means 15 is attached in the sheet feeding direction so as to surely separate the sheet fed by the feed roller 7 into one sheet. In this embodiment, the transport roller 21 is constituted by the transport roller 21 and the separation roller 22 which comes into contact with the transport roller 21.

With the above-described configuration, the loaded paper pressed by the feeding roller 7 by the pressing means 10 is
And is separated into one sheet via the elastic means 15 and the sheet separating means 20 attached to the regulating member 1b. Then, the sheet is guided into the printer 70 and is conveyed to a printing unit (not shown) via conveyance rollers 73 and 74 provided in the printer 70.

The feeding roller 7 is driven, and the paper is fed from the loaded paper.
The separated sheets are transferred to the transport rollers 73 and 7 on the printer side.
4, the feed roller 7 is
The rotation driving is stopped, and the paper is rotated together with the paper conveyance. Here, a configuration example of the driving force transmission mechanism of the automatic paper feeder shown in FIG. 1 will be described with reference to FIG. 3A and 3B show a configuration example in which a driving source is provided on the frame 1a. FIG. 3A shows a state in which the feed roller is driven, and FIG. 3B shows a state in which the feed roller rotates. The state is shown.

Drive source gear 30 supported on frame 1a
Are sequentially meshed with gear trains 31a, 31b and 32a, 32b supported by the frame 1a, and the speed is reduced via these gears. The gear 32b meshes with a sun gear 36 having a bifurcated swing arm 35 supported by the frame 1a. Planet gears 37 and 38 are supported at the tip of each arm of the bifurcated swing arm 35.
The gear 7 can mesh with the gear 21b, and the planet gear 38 can mesh with the gear 7b. The gear 21b is attached to the drive shaft 21a to which the transport roller 21 shown in FIG. 1 is fixed, and the gear 7b is attached to the drive shaft 7a to which the feed roller 7 is fixed. .

In this configuration, when the drive source gear 30 shown in FIG. 3A is driven clockwise, the drive is reduced via the gear trains 31a, 31b and 32a, 32b to reverse the sun gear 36. Rotate clockwise. By this rotation, the forked rocking arm 35 is rocked counterclockwise, and the respective planetary gears 37, 38 are driven by the gears 21b, 7 respectively.
meshes with b. Thus, the gears 7b and 21b are rotated counterclockwise, and the feed roller 7 and the transport roller 21 are rotated.
Is driven to rotate in the direction in which the paper is fed (see FIG. 1).

When the sheet is transported by the transport roller on the printer side, the driving source is stopped and the feed roller 7 is stopped.
The transport roller 21 rotates with the transport operation of the sheet. When the feeding roller 7 and the conveying roller 21 are rotated together, the respective gears 7b and 21b are rotated in the counterclockwise direction in FIG. It is ejected and the state shown in FIG. Therefore, the feed roller 7 and the transport roller 21
No load is applied from the drive source and the gear train side during the rotation. Then, when the drive source is driven again to feed out the next sheet, the state shown in FIG.

The operation of the automatic paper feeder constructed as described above when sheets having a large coefficient of friction are stacked and stored will be described. As shown in FIG. 4, when the feed roller 7 is driven in the paper feed direction, the stacked paper receives a force toward the regulating member 1 b as a whole due to the feed operation. As described above, the elastic member (sponge) 15 is provided on the regulating member 1b.
Is attached, the sponge 15 is elastically deformed in the sheet feeding direction from the state shown by the dotted line as shown by the solid line due to the force generated by this feeding operation. Then, while the sponge is elastically deformed, the state between the feeding roller 7 and the sheet and between the sheets shifts from the static friction state to the moving friction state. In this case, the kinetic frictional force between the sheets is much lower than the kinetic frictional force between the feed roller 7 and the sheet, so that one stacked sheet can be separated without causing double feed or non-feed.

This will be specifically described with reference to the graph of FIG. This graph is a graph showing the time since the drive of the feed roller 7 and the accompanying change in the coefficient of friction between the sheets and between the feed roller and the sheet.

In this graph, the value when Δt = 0 when the feed roller 7 is not driven is the static friction coefficient, a is the change in the friction coefficient between the feed roller 7 and the paper, and b is the normal value. Indicates the change in the coefficient of friction between the sheets, and c indicates the change in the coefficient of friction between the sheets having relatively large coefficients of friction, such as postcards and envelopes. As is clear from this graph, when the feed roller 7 is driven to be in a kinetic friction state, the kinetic friction coefficient between the sheets becomes
It drops sharply below the dynamic friction coefficient between the feed roller and the paper. Then, the friction coefficient between the feed roller and the paper and between the papers changes as shown in each graph and finally becomes a constant value. This value is the dynamic friction coefficient. Regardless of the paper quality of the loaded paper, the distance between the feed roller 7 and the paper is about 2.0, and the paper gap is about 0.5.

As described above, when the feeding roller 7 is driven, the loaded paper is displaced in the paper feeding direction by the elastic means 15 being elastically deformed as shown in FIG. Subject to separation. Assuming that the time during which the elastic means 15 elastically deforms is Δt1, as shown in the graph of FIG. 5, even when sheets having a large static friction coefficient between the sheets are stacked, the transition from the static friction to the dynamic friction occurs during the time Δt1, The friction force drops sharply. That is, while the elastic means 15 is elastically deformed, the frictional force acting between the papers is lower than the frictional force acting between the feeding roller and the papers. Even if the postcard or the envelope is high, one sheet of the stacked paper can be surely separated.

When one sheet of paper is separated, the feed roller 7 is stopped and enters a free rotation state. Therefore, the stacked paper is again shown by the dotted line in FIG. Then, the second and subsequent sheets are separated by the same procedure.

In the configuration shown in the figure, as described above, the lower end of the elastic means 15 projects from the lower end of the regulating member 1b, and as shown in FIG. The protruding portion bends in the feeding direction. When the elastic means 15 bends in this manner, the stacked sheets are guided in a wedge shape at a certain angle at the bent portion, so that the sheet is separated at the bent portion. That is, even before the separating roller 22, a separating action is added, so that one sheet can be reliably separated. Of course, the fed sheet is subjected to the separating action at the separation roller 22 as the separating means 20, so that the elastic means 15 may be attached to the regulating member without projecting from the lower end of the regulating member 1b. .

The embodiment of the automatic sheet feeder according to the present invention has been described above, but the present invention can be variously modified without being limited to the above embodiment. As described above, the present invention is characterized in that the loaded paper is slightly displaced in the feeding direction after the feeding roller is driven, so that a kinetic frictional force acts between the sheets. Therefore, if such a function is given to the stacked paper when the feed roller is driven,
Other configurations such as the paper stacking unit and the pressing unit are not particularly limited. In addition, the elastic means giving such an effect can be variously deformed in terms of its shape, arrangement location, number and the like.In addition to the sponge which elastically deforms as shown in the figure, for example, an elastic spring is used. Alternatively, the regulating member may be elastically deformed in the sheet feeding direction.

[0024]

According to the present invention, the frictional force acting between the papers can be reduced when the papers are fed, so that postcards and envelopes having a large frictional power between the papers can be loaded. One sheet can be separated without causing double feed, non-feed, or the like.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view showing a state in which an automatic paper feeder is mounted on a printer as a paper processing apparatus.

FIG. 2 is a plan view of the automatic sheet feeder shown in FIG.

3A and 3B are diagrams illustrating a configuration example of a driving force transmission mechanism of the automatic sheet feeder illustrated in FIG. 1, wherein FIG. 3A illustrates a state in which a feeding roller is driven, and FIG. The figure which shows the state at the time of turning around.

FIG. 4 is a diagram showing a state of elastic means when a sheet receives a separating action.

FIG. 5 is a graph showing the time from when the feed roller is driven and the accompanying change in the friction coefficient of the sheet and the feed roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic paper feeder 3 Mounting plate 7 Feeding roller 15 Elastic means 18 Film 70 Printer

Claims (2)

[Claims] 1. A sheet stacking means for stacking sheets, a feeding roller for sequentially feeding sheets from the lowest order of the stacked sheets, and an abutment on the top of the stacked sheets to feed the stacked sheets. An automatic paper feeder, comprising: a pressing means for pressing the sheet; and a regulating member for regulating a leading end of the stacked sheets, wherein the regulating member is provided with an elastic means capable of being deformed in the sheet feeding direction. apparatus. 2. The automatic sheet feeding device according to claim 1, wherein the sheet contact surface of the elastic means is a sliding surface on which the sheet slides.