JP2000103535A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive sheet feeder having excellent separability. SOLUTION: In a sheet feeder which sucks a highest paper sheet of loaded paper sheets by an air suction belt means 11 having a vacuum chamber 14, and feeds the paper sheets by separating them one by one by an air nozzle means 7, the air suction belt means 11 is arranged in an inclined manner so that its suction surface is separated from the paper surface of the paper sheet S downstream of the feeding direction of the paper sheet S, the vacuum chamber 14 has a turning support point upstream of the feeding direction of the paper sheet S, the suction surface of the air suction belt means 11 is supported in an oscillating manner at the approaching position parallel to the paper surface of the loaded paper sheet S and at the feeding position to feed the paper sheet S away from the paper surface, and the vacuum chamber 14 sets the approach/ separation to/from the paper surface of the paper sheet S by a driving means 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus, and more particularly, to a sheet feeding apparatus having a structure for feeding a sheet such as a recording sheet by a suction force.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine is used to feed a sheet such as a recording paper to a transfer position in order to transfer a visible image formed on a photoconductor such as a photoconductor. A sheet feeding device may be provided.

A sheet feeding device is configured to feed out one sheet by applying a suction force to the uppermost sheet among sheets stacked in a sheet storage unit such as a cassette. (For example, Japanese Patent Publication No. 57-
No. 20218). The sheet feeding apparatus disclosed in the above publication includes a vacuum casing which is located above a sheet stacking section and which can be moved up and down. In the vacuum casing, a feeding roller capable of contacting the uppermost sheet is provided together with the vacuum casing. It is designed to move. When feeding out a sheet using the sheet feeding device, the vacuum casing descends, and the feeding roller is brought into contact with the uppermost sheet, and the pressure in the vacuum casing is reduced to a negative pressure. The uppermost sheet is sucked on the front side in the feeding direction. Thereby, the uppermost sheet closely contacting the feed roller can be fed out by the feed roller.

[0004]

Among the fed sheets, coated paper and art paper have good smoothness on the surface of the sheet and have low air permeability and hygroscopicity. Adhesion between sheets tends to increase. For this reason, the feeding property is likely to be worse than that of sheet materials such as plain paper, and double feeding and continuous feeding are likely to occur frequently. In order to eliminate these problems and feed the sheet material one by one, an air feeding method using a suction cup as used in a printing machine is appropriate. It raises noise, increases power consumption, and is unsuitable for use in ordinary offices. Further, there is a difficulty in controlling the supply of air acting on the suction cup. Instead of using a suction cup, suction box air may be used.This method has the advantage that noise can be confined to a certain extent in the suction box, but it is advantageous in terms of noise. At present, high-speed feeding is inferior to the suction cup method.

An object of the present invention is to provide a conventional sheet feeding apparatus,
In particular, it is an object of the present invention to provide a sheet feeding apparatus having a configuration that is inexpensive and has good separability in view of the problem of the sheet feeding apparatus having a configuration using a suction box.

[0006]

According to the first aspect of the present invention,
The uppermost one of the stacked sheet papers is suctioned by an air suction belt means having a vacuum chamber,
In the sheet feeding apparatus in which the sheet is separated and fed one by one by an air nozzle unit, the air suction belt unit moves the suction surface away from the sheet surface of the sheet paper toward a downstream in the sheet feeding direction. The vacuum chamber has a rotation fulcrum upstream of the sheet paper feeding direction so that the suction surface of the air suction belt means is parallel to the paper surface of the stacked sheet paper. And a feeding position for feeding the sheet paper away from the paper surface, wherein the vacuum chamber is set so as to move toward and away from the paper surface by driving means. .

According to a second aspect of the present invention, in the sheet feeding apparatus of the first aspect, the belt means of the air suction belt means is constituted by an elastic endless belt having a large number of ventilation holes on a surface thereof. When the vacuum chamber approaches the paper surface of the stacked sheet paper, a side facing the paper surface of the sheet paper is extended by the vacuum chamber toward the stack paper side and is spread. .

[0008]

FIG. 1 is a schematic diagram for explaining a main part of a sheet feeding apparatus according to an embodiment of the present invention. In FIG. 1, a sheet feeding apparatus 1 includes a sheet feeding table 2 which can be raised and lowered. Have. The paper feed table 2 is engaged with a part of a belt 4 hung on a pair of pulleys 3, 3 ′, and one of the pulleys 3 is driven by an elevation drive motor 5 to move the belt 4 in a moving direction. Go up and down accordingly.

A sheet S is loaded on the sheet supply table 2, and the sheet S is supplied to a downstream end of the sheet feeding direction (indicated by reference F for convenience) corresponding to the feeding direction of the sheet S. A positioning side plate 6 for aligning the leading end sides in the feeding direction is arranged. Above the positioning side plate 6, there is provided a separation chamber 7 functioning as an air nozzle means facing the leading end of the sheet S in the feeding direction. The separation chamber 7 has a space in which air from the fan 8 is supplied, and the upper surface is formed as a guide surface of the sheet S,
Further, air outlets 7A and 7B are formed on the side wall and the upper surface facing the leading end in the feeding direction of the sheet paper S, respectively. The air outlet 7A blows air toward the leading end side in the feeding direction corresponding to the downstream side in the feeding direction of the stacked sheet papers S, and as shown in FIG. It is used to weaken the force and separate the sheets from each other. Air outlet 7B
Is used to press the sheet paper S approaching the upper surface toward an air suction belt device 11 described later.

A paper surface detection sensor 9 for detecting the amount of stacked sheet paper S on the upstream side in the feeding direction of the sheet paper S, And a rotatable paper pressing roller 10 which comes into contact with the paper holding roller 10.

An air suction belt device 11 is disposed above the paper feed table 2. Air suction belt device 11
Has an elastic belt 13 wrapped around a driving pulley 12 and a driven pulley 12 ′, and a vacuum chamber 14 built in between the elastic belts 13 and capable of swinging about the driven pulley 12 ′ as a fulcrum. . Elastic belt 13
Is that the driving pulley 12 is disposed higher than the driven pulley 12 ′, so that the suction surface facing the sheet paper S is inclined so as to move away from the sheet surface toward the downstream in the feeding direction of the sheet paper S. , Parallel to the upper surface which is the guide surface of the separation chamber 7 on the downstream side in the feeding direction. Further, a large number of ventilation holes (not shown) are formed in the elastic belt 13, and the inside of the vacuum chamber 14 is made negative pressure so that air can be taken in from the front side.

The vacuum chamber 14 can be oscillated by an oscillating cam 15 which is in contact with the surface of the paper feed table 2 opposite to the surface facing the sheet S, and the oscillating cam 15 is driven. It is interlocked with the drive motor 16 as a means.
The rotation of the swing cam 15 causes the vacuum chamber 14 to
As shown by the solid line in FIG. 1, the approach position parallel to the sheet surface of the topmost sheet sheet S on the paper feed table 2 and the position of the topmost sheet sheet S as shown by the two-dot chain line in FIG. It swings to a feeding position where the uppermost sheet S can be fed away from the paper surface. One end of an elastic member 17 such as a spring is hung on a surface of the vacuum chamber 14 with which the swing cam 15 abuts.
The elastic belt 13 has a habit of obtaining a state in which the elastic belt 13 is inclined away from the uppermost sheet of the sheet paper S on the downstream side in the feeding direction. Further, the suction portion of the fan 8 communicates with the vacuum chamber 14, and a suction port (not shown) is formed on a surface of the vacuum chamber 14 which faces the uppermost sheet S.

In FIG. 1, reference numeral 18 denotes a conveying roller for feeding the sheet S fed from the paper feed table 2;
Reference numeral 19 denotes a paper detection sensor that detects the feeding state of the fed sheet.

Since the present embodiment has the above configuration,
When the sheet S is not fed, the swinging cam 15 that is in contact with the vacuum chamber 14 is maintained in the position shown by the solid line in FIG. For this reason, the vacuum chamber 14 is kept away from the uppermost sheet of the sheet S, so that the elastic belt 13 moves the axial center of the driving pulley 12 and the driven pulley 12 'as shown by a solid line in FIG. The sheet is maintained in a state parallel to the connecting straight line and inclined with respect to the sheet surface of the sheet paper S.

The separation chamber 7 blows out positive-pressure air (indicated by A and B in FIG. 1) from air outlets 7A and 7B by air supplied from a fan 8 (indicated by D in FIG. 1). I have. For this reason, as shown in FIGS. 2 and 3, the leading end of the sheet S in the feeding direction, which corresponds to the downstream side in the feeding direction, is weakened due to the weak adhesion between the sheets.
That is, since the rear end of the sheet S in the feeding direction is pressed by the paper pressing roller 10 disposed on the upstream side in the feeding direction, the air (A) blown to the front end in the feeding direction is supplied in the feeding direction. Instead of coming off from the rear end, it comes off sideways as shown in FIG. 2 (state indicated by an arrow). As a result, the pressure between the sheet papers S is increased, and the sheet papers are weakened in adhesion and are easily separated. Further, the air outlet 7 located on the upper surface of the separation chamber 7
The air (B) blown from B directs the sheet S toward the air suction belt device 11.

When the sheet S is fed, the swing cam 1
5 rotates half a turn from the state shown by the solid line, and pushes down the vacuum chamber 14 as shown by the two-dot chain line. When the vacuum chamber 14 is pushed down, the elastic belt 13 is extended downward and pushed down, as shown by a two-dot chain line in FIG. 1, and moves to an approach position parallel to the uppermost sheet S. At this time, the pressure inside the vacuum chamber 14 is reduced to a negative pressure by the intake air from the fan 8 (reference numeral C in FIG. 1).
Therefore, the uppermost sheet S is sucked into the elastic belt 13 through the air holes of the elastic belt 13.

When the uppermost sheet S rises slightly due to the negative pressure generated in the vacuum chamber 14, air blown from the air outlet 7A located on the side wall of the separation chamber 7 enters between the sheet S. In FIG. 3, since the sheet paper S can be pushed and spread in the direction indicated by the reference character C, the adhesion between the paper sheets sharply decreases.

The swing cam 15 is further rotated by half a turn,
When the state is returned from the state shown by the two-dot line to the state shown by the solid line, the vacuum chamber 14 returns to the original position, and the elastic belt 13 is inclined with respect to the sheet surface of the sheet S on the sheet feed table 2. At this time, the uppermost sheet S adsorbed on the elastic belt 13 is directed toward the air suction belt device 11 by air from the air outlet 7B located on the upper surface of the separation chamber 7.

The elastic belt 13 of the air suction belt device 11
The sheet S that has been sucked is fed to the transport roller 18 by the elastic belt 13 moving in conjunction with the rotation of the driving pulley 12 and the driven pulley 12 ′.

[0020]

According to the first aspect of the present invention, the vacuum chamber having the rotation fulcrum on the upstream side in the sheet paper feeding direction makes the suction surface of the air suction belt means parallel to the uppermost paper surface of the sheet paper. With a simple structure that swings between the approach position and the feeding position where it can be separated upward, the separation starts from the vicinity of the downstream end of the sheet paper in the feeding direction, in other words, the part that is easy to peel. Can be done. For this reason, even when the adhesion between the sheet papers is strong, the uppermost sheet paper can be easily raised. In addition, when the sheet is separated from the sheet surface toward the feeding position, the suction surface is inclined, so that even if two or more sheets are sucked, the sheet paper other than the top sheet has a bending rigidity corresponding to its own waist strength. Separability can be ensured by making it easier to return to the loaded state. Further, if the sheet paper rises to some extent due to the movement of the suction surface, air from the air nozzle means enters, so that the sheet paper is pushed and spread, so that it is possible to rapidly reduce the adhesion force. This makes it possible to further enhance the separability between sheets.

According to the second aspect of the present invention, the elastic belt is extended by the vacuum chamber so that the side facing the sheet surface of the sheet paper is extended toward the sheet paper side, so that the elastic belt is extended and supported in an inclined state. Irrespective of the supporting position of the present member, it is possible to approach the sheet paper side. This makes it possible for the air suction belt means to efficiently approach the end face side of the sheet paper and to easily perform separation from the end face side.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a main configuration of a sheet feeding apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a separated state according to a main part configuration shown in FIG. 1;

FIG. 3 is a schematic diagram for explaining another separation state according to the main part configuration shown in FIG. 1;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 sheet feeding device 2 paper feed table 7 separation chamber 7A and 7B functioning as air nozzle means air outlet 11 air suction belt device 13 elastic belt 14 vacuum chamber 15 swing cam 16 drive motor

Claims (2)

[Claims] 1. A sheet feeding apparatus for adsorbing the highest one of stacked sheet papers by an air suction belt means having a vacuum chamber and separating and feeding the sheets one by one by an air nozzle means. The belt means is inclinedly disposed so that its suction surface is separated from the sheet surface of the sheet paper toward the downstream in the sheet sheet feeding direction, and the vacuum chamber is rotated upstream in the sheet sheet feeding direction. It has a fulcrum and swingably supports the suction surface of the air suction belt means at an approach position parallel to the sheet surface of the stacked sheet paper and at a feeding position for feeding the sheet sheet away from the sheet surface. Wherein the vacuum chamber is set so as to approach and separate the sheet paper from the paper surface by a driving means. Location. 2. The sheet feeding device according to claim 1, wherein the belt means of the air suction belt means is constituted by an elastic endless belt having a large number of air holes on a surface thereof, and the vacuum chamber is loaded thereon. A sheet feeding apparatus characterized in that a side facing the sheet surface of the sheet paper is extended and pushed toward the stacking sheet side by a vacuum chamber when approaching the sheet surface of the sheet sheet.