JPH1143235A - Sheet feeding device - Google Patents

Abstract

[PROBLEMS] To provide a sheet feeding device capable of preventing deformation of recording material suction means regardless of the type and the number of stacked recording materials, and an image forming apparatus including the same. SOLUTION: By forming a recording material suction means 2 for generating a negative pressure in a concave portion 2a on the bottom surface to suction the sheet P by a flexible member, the edge of the concave portion 2a can be formed at the time of sheet suction. The sheet P is deformed while closely contacting in a direction of spreading outward along the surface of the sheet P attracted by the internal negative pressure.
Further, when the sheet is attracted, the concave edge portion 2b of the recording material attracting means 2 which is deformed in the direction of expanding outward is brought into contact with the height regulating member 60 to keep the deformation within a predetermined range. The change in the height direction at the time of suction is regulated.

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 an image forming apparatus having the same, and more particularly to a sheet feeding apparatus in which recording materials are sucked one by one by a recording material suction member and fed.

[0002]

2. Description of the Related Art Conventionally, some image forming apparatuses such as a copying machine and a printing machine have an air suction type sheet feeding device as a sheet feeding device. Such a sheet feeding apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-78743.
As disclosed in Japanese Patent Application Laid-Open No. H06-230050, a recording material suction means, a moving means for supporting and moving the recording material suction means, and a recording material suction means for continuously applying a suction force to the recording material suction means. And a suction force generating means for generating a negative pressure, and the recording material is fed by moving the recording material suction means which has sucked the recording paper by the moving means.

The suction pad, which is a recording material suction means, is usually formed of a flexible member such as urethane rubber having an appropriate hardness. It has a very thin conical shape. In addition, by making the portion which comes into contact with the recording material into such a shape, the contact portion can be easily deformed when the recording material is sucked, and can be in close contact with the surface of the recording material. .

[0004]

However, in such a conventional sheet feeding apparatus, when such a suction pad is used to adsorb a recording material having no air permeability, such as polyethylene terephthalate, The suction negative pressure value in the suction pad is unnecessarily increased as compared with a case where a so-called plain paper, which is a sheet of paper and has a breathable recording material, is sucked. As a result, the conical shape of the suction pad is deformed until it becomes almost flat, and the position in the height direction is different between the two recording materials, and there is a problem that it is difficult to feed the conveyer to the next pair of rollers as the conveying means. Was.

Further, prior to suction of the recording material, when the suction pad is brought into contact with a large number of recording materials loaded and the position of the uppermost recording material is high, the suction pad is pressed against the recording material with a strong pressing force. Will be able to Then, when pressed with such a strong pressing force, the conical shape of the suction pad is deformed until it becomes a substantially flat plate shape, and the suction area is substantially reduced. There was also a problem that an attraction force could not be obtained.

Accordingly, the present invention has been made in view of such circumstances, and a sheet feeding apparatus capable of preventing deformation of recording material suction means regardless of the type of recording material to be suctioned and the number of stacked sheets. And an image forming apparatus having the same.

[0007]

According to the present invention, there is provided a sheet feeding apparatus for sucking and feeding a sheet stacked on a sheet stacking means, having a concave portion on a bottom surface and generating a negative pressure in the concave portion. A flexible member that adheres to the sheet while adsorbing the sheet and, at the time of adsorbing the sheet, deforming the edge of the concave portion along the surface of the adsorbed sheet in a direction to expand outward due to the internal negative pressure. The recording material suction means is provided above the sheet stacking means so as to be movable upward and downward, and holds the recording material suction means. A moving means for moving the recording material in a predetermined direction by contacting a concave edge portion of the recording material suction means, which deforms in the outwardly expanding direction when the sheet is suctioned, When sucking The height regulating member for regulating the changes in the height direction, is characterized in that it comprises a.

Further, the invention is characterized in that the height regulating member and the recording material suction member are integrally and rotatably held by the moving means.

Further, the present invention is characterized in that the height regulating member and the recording material suction member are separately and rotatably held by the moving means.

Further, in the present invention, the height regulating member and the recording material attracting member are held by the moving means in a positional relationship in which the recording material attracting member is inscribed in the height regulating member when the sheet is attracted. It is characterized by being performed.

Further, in the present invention, the height regulating member and the recording material attracting member are held by the moving means in a positional relationship in which the recording material attracting member circumscribes the height regulating member during the sheet attracting. It is characterized by being performed.

Further, the present invention is characterized in that the recording material suction means has a substantially conical shape, and the concave portion also has a substantially conical shape.

According to the present invention, there is provided an image forming apparatus comprising an image forming section and a sheet feeding apparatus for feeding a sheet to the image forming section. It is characterized by any one of the above.

Further, as in the present invention, the recording material suction means for suctioning the sheet by generating a negative pressure in the recess at the bottom surface is formed by a flexible member, so that the edge of the recess at the time of sheet suction is formed. The portions are deformed while closely contacting in the direction of spreading outward along the surface of the sheet that is attracted by the internal negative pressure. Also, at the time of sheet suction, the edge of the concave portion of the recording material suction means, which deforms in the direction of expanding outward, is brought into contact with the height regulating member to keep the deformation within a predetermined range, so that when the recording material suction means is sucked. Restrict height changes.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a copying apparatus as an example of an image forming apparatus provided with a sheet feeding apparatus of the present invention. In FIG. 1, reference numeral 50 denotes a copying apparatus. The copying apparatus 50 includes a paper cassette 55 as sheet stacking means on which recording paper P as a sheet is stacked. The recording paper P stacked in the paper cassette 55 is supplied by the sheet feeding device 1A. After being fed to the pair of paper rollers 15 and 16, the process cartridge 52 passes through a pair of registration rollers 63 a and 63 b having a function of correcting the inclination of the recording paper P.
To be transported to

The recording paper P on which an image has been formed by the process cartridge 52 is further transported by a transport belt 73.
The image is fixed by being guided to a fixing device 75 via a pre-fixing guide 74, and thereafter discharged from a discharge port 78 downstream of the fixing device 75 and placed on a discharge tray 79.

Here, the process cartridge 52
Is constituted by a photosensitive drum 68, a developing sleeve 67, a cleaning blade 69 of the photosensitive drum, a toner (not shown), a stirring mechanism thereof, and a waste toner container. A transfer charger 70 is provided at a position facing the photosensitive drum 68.

On the other hand, the transport belt 73 has rollers 71, 7
2 and rotatably supported by rollers 72
Are driven by driving means (not shown). The transport belt 73 is given an appropriate tension by a tensioner (not shown) of the roller 72.

The fixing device 75 includes a heat roller 76 having a built-in heater and a pressure roller 77.
Thermal fixing of the toner printed on the recording paper P is performed in the nip portions 6, 77. The pressure roller 77 is pressed against the heat roller 76 by a spring (not shown).

In FIG. 1, reference numeral 80 denotes a platen glass on which a document is placed. Below the platen glass 80, an illumination lamp 81, an image forming lens 85, and mirrors 82, 8 are provided.
An optical system including 3, 84, and 86 is provided, and the optical system irradiates a predetermined position of the photosensitive drum 68 with reflected light 87 from the document.

Reference numeral 91 denotes a pressure plate which is disposed on the platen glass 80 so as to be openable and closable, and which presses the document appropriately.
Reference numeral 1 is provided with a pressure contact sheet 90 made of a sponge-like member having an appropriate hardness on the original contact surface side. Reference numeral 96 denotes a manual paper feed port. The manual paper feed port 96 is used when a recording material such as thick paper or thin paper which is difficult to feed from a cassette is used. The recording material from the manual paper feed port 96 is conveyed by rollers 97 and 98.

FIG. 2 shows the sheet feeding apparatus 1A.
FIG. 3 is a schematic perspective view of the sheet feeding apparatus.
It is -A sectional drawing.

In FIGS. 2 and 3, reference numeral 1 denotes a main frame of the sheet feeding device 1A, on which members constituting the sheet feeding device 1A are fixed or engaged.

Reference numeral 2 denotes a pair of suction pads, which are sheet suction members, and a concave portion 2a having a substantially conical shape is formed on the bottom surface of the suction pad 2. By generating a negative pressure in the concave portion at the time of sheet feeding, it is possible to adsorb both ends of the recording sheet P cut in advance to a fixed size in the feeding direction.

As described above, the suction pad 2 is formed of a flexible member such as urethane rubber having an appropriate hardness and has a relatively thin conical shape. When the P is sucked, the edge 2b of the concave portion 2a that comes into contact with the recording material 9 is deformed along the surface of the recording paper P in a direction in which the edge 2b expands outward due to an internal negative pressure, so that the edge 2b adheres to the recording paper P Has become.

By the way, the suction pad 2 is held by the height regulating member 60 while maintaining a close contact without air leakage. Here, at both ends of the height regulating member 60,
Legs 60a bent downward are provided, and the suction pad 2 is formed such that the edges 2b of the recesses 2a are inscribed with the legs 60a when deformed during suction.
are held with a predetermined gap formed between them.
The lengths of the legs 60a are such that the lower ends thereof are higher than the lower ends of the suction pads 2 by a predetermined height (for example, 1 to 5 mm).

The height restricting member 6 having such a structure is used.
0 when the suction pad 2 is held,
The edge 2b of the concave portion 2a that is deformed in the direction along the surface of the recording material is inscribed in the leg 60a of the height regulating member 60, so that the suction pad 2 is suppressed from being deformed without limit.

By suppressing the deformation of the suction pad 2 by the height restricting member 60 in this manner, it is possible to restrict the change in the height direction, whereby the suction pad 2 can be suctioned regardless of the type of the recording material P. Thus, the height position of the recording material P can be always kept constant, and the recording paper P can be reliably transferred to the paper feed roller pairs 15 and 16.

Reference numeral 3 denotes a swinging arm which holds the suction pad 2 and the height regulating member 60 at one end integrally and rotatably within a predetermined range. Is rotatably supported via a pin 3a.

The swing arm 3 has an end 3b (hereinafter referred to as the other end) on the side not holding the suction pad 2 by a tension coil spring 7 mounted between the swing arm 3 and the moving table 5. It is urged in the direction of lifting, that is, the direction of pressing the suction pad 2 and the height regulating member 60 toward the recording paper. The swing arm 3 and a first cam 9 described later are used.
Thus, a moving means for moving the suction pad 2 and the height regulating member 60 in the recording paper P direction is configured.

The moving table 5 has a part of the bracket 5.
By engaging the groove portion 5a 'of "a" with a not-shown notch of the main frame 1, it is slidably held by the main frame 1 and recorded by a tension coil spring 6 having one end fixed to the main frame 1. The paper P is urged in the feeding direction.

Reference numeral 4 denotes a recording paper presser. The recording paper presser 4 is rotatably supported by the turning arm 3 via a pin 4a, and is urged downward by a compression spring 40 in the drawing.
Further, it is stopped at a predetermined position by a stopper 4b.

Reference numeral 8 denotes a drive shaft connected to a motor (not shown). The drive shaft 8 rotates the first cam 9, the second cam 10, and the third cam 13. The first cam 9 comes into contact with the other end 3b of the swing arm 3 from above to move the swing arm 3 up and down. Further, the second cam 10 comes into contact with the contact portion 5b formed at the end (hereinafter referred to as the other end) of the movable base 5 opposite to the side on which the tension coil spring 6 is attached, from the inside,
This is for moving the movable table 5 in parallel with the tension coil spring 6.

The third cam 13 is for driving the suction pump 11 by rotating a link 12 for driving the suction pump 11 which is a suction force generating means around a rotation shaft 12a. . Here, this suction pump 11
Has the ability to secure a negative pressure to obtain a predetermined suction force even when using plain paper with relatively high air permeability or recording paper generally used in copiers by obtaining a predetermined drive. And is fixed to the main frame 1 by the bracket 11a.

The suction pump 11 is configured to generate a predetermined negative pressure during the upward operation of a vertically movable partition (not shown) provided inside the suction pump 11. 14 and 14a make it possible to reach the suction pad 2. The suction pad 2 has a suction force capable of suctioning a predetermined number of recording sheets by the negative pressure.

The link 12 has two substantially L-shaped arms 121 and 122 and is rotatably attached to the main body of the sheet feeding apparatus. Note that one arm 121 of the link 12 is urged by an urging means (not shown) to press against the third cam 13, and the other arm 122 moves the movable portion 11 b of the suction pump 11 so as to drive the suction pump 11. Is engaged with the upper end.

On the other hand, the paper feed roller pairs 15 and 16 are urged by urging means (not shown) in a direction approaching each other.
It is driven by a motor (not shown) to convey the recording paper P. In addition, this paper feed roller pair 15, 1
Reference numeral 6 designates one sheet of recording paper P by rotating one roller 16 in a direction opposite to the sheet feeding direction in order to constitute a paper separating means.
Only the copy may be conveyed into the copying apparatus.

In the present embodiment, the suction pads 2,
A swing arm 3, a recording paper holder 4, a moving table 5, a tension coil spring 6, a tension coil spring 7, a first cam 9, a second cam 10, a third cam 13 and the like are provided in two sets each. It is also possible to cope with recording paper of relatively large dimensions arranged at a distance of.

The operation of the present embodiment in the above configuration will be described with reference to FIGS. FIGS. 3 to 7 show a state in which the number of recording materials loaded on the paper cassette 55 is large and the position of the uppermost recording material is high.

FIG. 3 shows a standby state before paper feeding. In this state, the largest portion of the first cam 9 is in contact with the other end 3b of the swing arm 3 from above, so that the swing arm 3 keeps a substantially horizontal state, and the suction pad 2 is used for recording. It is separated from the paper P. In addition, the second cam 10 has the largest radius portion in contact with the contact portion 5b of the movable base 5, whereby the movable base 5 is stopped at the left end position of its movable range.

Further, the recording paper retainer 4 includes a compression spring 40.
, And is stopped at a predetermined position by the stopper 4b, and is separated from the recording paper P. In addition, the third cam 13 is in contact with the first arm 121 of the link 12 in a state before the movable portion 11b of the suction pump 11 is pulled up, so that the suction pump 11 does not generate a negative pressure. It is in a state.

FIG. 4 shows a state in which the suction pad 2 attempts to suck the recording paper P. In this state, the first cam 9, the second cam 10, and the third cam 13 are moved from the state shown in FIG. 8 and starts to rotate in the direction of arrow R. Here, the first cam 9 is separated from the other end 3b of the swing arm 3 by the rotation of the first cam 9 by this rotation. It swings downward by the force, whereby the leg 60a of the height regulating member 60
And the suction pad 2 come into pressure contact with the recording paper P.

When the number of recording materials loaded on the paper cassette 55 is reduced, the first cam 9 has its minimum radius abutting on the other end 3b of the swing arm 3 and swings accordingly. The suction pad 2 side of the arm 3 swings further downward than in the case of FIG.

The recording paper presser 4 is urged downward by the compression spring 40 to abut the recording paper P and press the recording paper P. At this time, the second cam 10 has the largest radius portion still in contact with the contact portion 2b of the movable base 5, whereby the movable base 5 stops at the left end position of its movable range. I have.

On the other hand, the third cam 13 has its maximum radius gradually contacting the link 12, and the movable portion 11 b of the suction pump 11 is being pulled upward through the link 12. As a result, the suction pump 11 generates a negative pressure, and air flows in due to the air permeability of the recording material P. However, the negative pressure value in the suction pump 11 reaches a value sufficient to adsorb the recording material P. Then, the suction of the recording paper P is started at a predetermined negative pressure value.

When the suction of the recording paper P is started in this way, the suction pad 2 adheres to the surface of the recording material while being deformed. At this time, the height regulating member 60 comes into pressure contact with the recording paper P. Therefore, the edge 2b of the concave portion 2a deformed in the direction along the surface of the recording material corresponds to the leg 60 of the height regulating member 60.
comes to be inscribed in a. Accordingly, even when the recording paper P has no air permeability and the suction negative pressure value in the suction pad is increased more than necessary, it is possible to suppress endless deformation.

By keeping the deformation of the suction pad 2 within a predetermined range, the suction pad 2 maintains a predetermined shape and suppresses deformation in the height direction regardless of the type of the recording material P. it can. Thereby, the height position of the recording paper P to be sucked can be always kept constant.

As described above, when the number of recording materials loaded on the paper cassette 55 is large, the height regulating member 60
By keeping the deformation of the suction pad 2 within a predetermined range, it is possible to prevent the suction pad 2 from being deformed until it becomes almost flat. Thus, the suction area can be substantially set to an area where a suitable suction force can be obtained.

FIG. 5 shows a state in which only the uppermost recording paper P 'among the attracted recording papers P is separated. In this state,
The first cam 9 has a portion having an intermediate radius between the maximum radius and the minimum radius of the first cam 9 abuts on the other end 3b of the swing arm 3, whereby the swing arm 3 is slightly shifted from the state shown in FIG. With this, the suction pad 2 moves upward, and the uppermost recording sheet P ′ is pulled upward. The recording paper presser 4 is urged downward in the figure by a compression spring 40, contacts the uppermost recording paper P ', and presses the recording paper P'.

Here, the second sheet from the top has a weaker attraction force than the uppermost recording sheet P ′, and is thus held down by the separation claw 20 and the recording sheet holder 4 to the weaker attraction force. During this time, the rigidity of the recording paper overcomes, and there is also a frictional force due to the pressing force from the recording paper retainer 4, so that the second and subsequent sheets are separated from the uppermost recording paper P '.

On the other hand, the second cam 10 has the largest radius in contact with the moving table 5 and stops at the left end position of its movable range. The third cam 13 is still in contact with the link 12 at its maximum radius. When the recording paper P has air permeability, air flows in. However, since the inflow speed is low, the negative pressure in the suction pump 11 also maintains a predetermined negative pressure value. Adsorb paper P '.

FIG. 6 shows a state in which the sucked recording paper P ′ is sent out toward the pair of paper feed rollers 15 and 16.

In this state, the largest portion of the radius of the first cam 9 abuts on the other end 3b of the swing arm 3, whereby the swing arm 3 returns to a substantially horizontal state. Further, since the second cam 10 has a minimum portion of the radius abutting on the moving table 5, the moving table 5 moves in the arrow X direction by the spring force of the extension coil spring 6.

The swing arm 3 and the moving table 5
, The suction pad 2 lifts the uppermost recording sheet P ′ to a predetermined position, moves to the predetermined position, and transfers the recording sheet P ′ to the pair of paper feed rollers 15 and 16. Here, the recording paper presser 4 is stopped at a predetermined position similar to the position shown in FIG. Is extremely small, so that there is no trouble in conveying the recording paper.

The contact position of the third cam 13 with the link 12 is at the position where the movable portion 11b of the suction pump 11 is returning to the state before the movable portion 11b is pulled upward, and the third cam 13 has the air permeability of the recording paper P. Therefore, there is air guided into the pump by the suction operation, and the air is being discharged.
Indicates a state in which no negative pressure is generated, and the feed roller pair 1
The unnecessary suction force of the suction pad 2 after the transfer to the suction pads 5 and 16 is not generated.

FIG. 7 shows a state in which the recording paper P 'is returned to the position for the next paper feeding while the recording paper P' is being delivered to the paper feeding roller pairs 15 and 16.

In this state, the first cam 9 has the largest part of its radius in contact with the other end 3b of the swing arm 3, whereby the swing arm 3 returns to the horizontal state and the suction pad 2
Is a state in which the recording paper P 'is lifted to a predetermined position. In addition, the second cam 10 has its minimum radius in contact with the contact portion 5b of the moving base 5 so that the moving base 5
Ends the movement in the arrow X direction and stops at a predetermined position.

The third cam 13 has its minimum radius abutting on the link 12, whereby the movable portion 11b of the suction pump 11 returns to the operating position before suction, and the height regulating member 60 and the suction pad 2 are separated. The state is the same as that of FIG.

As described above, at the time of suction, the suction pad 2 that is deformed in the direction that expands outward is brought into contact with the height regulating member 60 to keep the deformation within a predetermined range, so that the height of the suction pad 2 during suction is reduced. Change in the direction of movement,
The recording paper can be stably fed into the copying apparatus 50.

After that, the recording paper P 'transferred to the pair of paper feed rollers 15, 16 is applied to the paper guide plate 6 shown in FIG.
Registration roller pair 63a, 63 while being guided by 5, 66
By b, it is transported to the process cartridge 52.
On the other hand, the image information of the original (not shown) is illuminated by an illumination lamp 81 below the original platen glass 80, reflected by an imaging lens 85 and mirrors 82, 83, 84, and 86, and becomes reflected light 87. Irradiation is performed at 68 predetermined positions.

The image formed on the photosensitive drum 68 is developed by the developing sleeve 67, and is transferred to the conveyed recording paper P 'by the transfer charger 70.
Further, the recording paper P ′ is further transferred to the fixing device 75 by the transport belt 73.
Sent to Then, the toner printed on the recording paper P ′ is thermally fixed by the heat roller 76, and thereafter,
The sheet is placed on the discharge tray 79 via the discharge port 78, and the recording is completed.

Next, a second embodiment of the present invention will be described.

FIG. 8 is a schematic perspective view of the sheet feeding apparatus according to the present embodiment, and FIG. 9 is a sectional view taken along line AA of FIG.

In this embodiment, the height regulating member 6
0 is rotatably held in the vicinity of the tip of the swing arm 3 within a predetermined range, and the suction pad 2 is
It is configured to be rotatable in a predetermined range near the tip of the swing arm 3 separately from the pivot arm 3.

By separately attaching the suction pad 2 and the height regulating member 60 to the swing arm 3 in this manner, when each component is replaced, the replacement operation becomes easier. Note that other configurations and operations are the same as those of the first embodiment, and a description thereof will be omitted.

Next, a third embodiment of the present invention will be described.

FIG. 10 is a schematic perspective view of the sheet feeding apparatus according to the present embodiment.

In this embodiment, the height regulating member 6
The leg portion 60b is made cylindrical, and the leg portion 60b is made cylindrical so that the height regulating member 6
Numeral 0 covers the entire circumference of the suction pad 2 so that height regulation can be performed more reliably. Note that other configurations and operations are the same as those of the first embodiment, and a description thereof will be omitted.

In the first to third embodiments described above, the height regulating members 60 are provided for one suction pad 2 so that the suction pad 2 is inscribed. Has been described.

However, the present invention is not limited to this. For example, the suction pads 2 and the height regulating members 60 are provided in different numbers, and for example, two suction pads 2 and a width close to the distance between the two suction pads 2 are provided. Height regulating member 60 is provided in the middle thereof,
The two suction pads 2 are each provided with a common height regulating member 6.
A similar effect can be obtained even if the configuration is made so as to circumscribe 0.
Further, the swing arm and the height regulating member may be integrated.

[0072]

As described above, according to the present invention, when a recording material is adsorbed, deformation of the suction pad in the height direction is suppressed by the height regulating member, so that the recording material is not affected by the type of the recording material. The height position after suction is always constant, and it is easy to feed the roller to the next conveying means, such as a roller pair. In addition, even when the number of recording materials loaded is large, the suction area can be reduced without reducing the suction area.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a copying apparatus as an example of an image forming apparatus provided with a sheet feeding device of the present invention.

FIG. 2 is a schematic perspective view of the sheet feeding device.

FIG. 3 is a sectional view of the sheet feeding device taken along line AA.

FIG. 4 is a diagram showing a state when the sheet feeding device starts a recording paper suction operation.

FIG. 5 is a diagram showing a state in which only the uppermost recording paper is separated from the recording paper sucked by the recording paper suction operation.

FIG. 6 is a diagram showing a state in which the sucked recording paper is sent out to a pair of paper feed rollers.

FIG. 7 shows the state in which the recording paper is transferred to a pair of paper feed rollers.
FIG. 9 is a diagram illustrating a state in which the printer returns to a position prepared for the next sheet feeding.

FIG. 8 is a schematic perspective view of a sheet feeding device according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of the sheet feeding device taken along line AA.

FIG. 10 is a schematic perspective view of a sheet feeding device according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1A Sheet feeding device 2 Suction pad 2a Recess 2b Recess edge 3 Swing arm 11 Suction pump 9 First cam 50 Copying device 55 Paper cassette 60 Height regulating member P, P 'Recording paper

Claims (7)

[Claims] 1. A sheet feeding apparatus for sucking and feeding sheets stacked on a sheet stacking means, wherein the sheet has a concave portion on a bottom surface and generates a negative pressure in the concave portion to suck the sheet, At the time of suction, the recording material suction formed by a flexible member so that the edge of the concave portion is deformed in the direction of expanding outward due to the internal negative pressure along the surface of the sheet to be sucked and adheres to the sheet. Means for moving the recording material suction means in the sheet suction direction while holding the recording material suction means, and moving the recording material suction means in the sheet suction direction, while being provided movably in the vertical direction above the sheet stacking means; When the sheet is sucked, the deformation is kept in a predetermined range by contacting the concave edge portion of the recording material suction means which deforms in the outwardly expanding direction, and the height change when the recording material suction means is sucked. Regulate And a height regulating member. 2. The sheet feeding apparatus according to claim 1, wherein the height regulating member and the recording material suction member are integrally and rotatably held by the moving means. 3. The sheet feeding apparatus according to claim 1, wherein the height regulating member and the recording material attracting member are separately and rotatably held by the moving means. 4. The height regulating member and the recording material attracting member are held by the moving means in a positional relationship in which the recording material attracting member is inscribed in the height regulating member when the sheet is attracted. The sheet feeding device according to any one of claims 1 to 3, wherein: 5. The height regulating member and the recording material attracting member are held by the moving means in a positional relationship in which the recording material attracting member circumscribes the height regulating member when the sheet is attracted. The sheet feeding device according to any one of claims 1 to 3, wherein: 6. The sheet feeding device according to claim 1, wherein the recording material suction means has a substantially conical shape, and the concave portion also has a substantially conical shape. apparatus. 7. An image forming apparatus comprising: an image forming unit; and a sheet feeding device that feeds a sheet to the image forming unit, wherein the sheet feeding device is any one of claims 1 to 6. An image forming apparatus according to any one of the preceding claims.