JPH09286533A - Sheet feeder, image forming device, and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a sheet feeder and an image forming device certainly capable of sheet supply by preventing any bad separation and unsatisfactory paper sheet supply, etc., as the result of avoiding any double feed of paper sheet by only feeding the paper sheet on the separated bottom surface side, by preventing any shift of the paper sheet by means of regulation of supply feed of only the loaded paper sheets other than those on the separated bottom surface side. SOLUTION: When an air flow ejected from a floating up means 105 is blown to the side surface of loaded paper sheet after hitting a paper sheet loading means 100, the loaded paper sheets float up in form of a bundle including the bottom surface sheet. The floating up loaded sheets are prevented from their supply feed by means of a tip end regulation member 500 so that the bottom surface sheet separated from the loaded sheets is transported from a gap G below the tip end regulation member 500 by a sheet supply feed means 101.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for separating and feeding sheets one by one, a copying machine, a printer,
The present invention relates to an image forming apparatus such as a facsimile, and more specifically, a sheet feeding apparatus and an image forming apparatus that separates and feeds a plurality of sheets such as originals and recording sheets stacked on a sheet stacking unit one by one from the lowermost surface side. Regarding the device.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, there is used a sheet feeding apparatus that sequentially feeds stacked sheets of originals or recording sheets one by one from the uppermost surface or the lowermost surface. In such a sheet feeding apparatus, the sheet separating means includes a separation method in which air is jetted from the downstream side to the upstream side in the sheet conveying direction to separate the sheets, and a roller that rotates in the opposite direction to the sheet feeding direction. There is a separation method using a (retard roller).

However, in the above-described separation method in which air is jetted from the downstream side to the upstream side in the transport direction to separate the stacked sheets, the stacked sheets are blown back by the jetting air flow, so that a member for regulating the rear end of the sheets is regulated. Is mandatory.
Further, when sheets such as originals having different sizes are mixed, the stacking position of the small-sized sheets may not be constant, so that the sheet may not be conveyed well. Further, in the retard roller system, since the difference between the coefficient of friction between the sheets and the difference between the coefficient of friction between the sheets and the roller is used, pressure must be applied to the sheet, and sheet stain called edge stain may occur.

Among the above, as a sheet feeding apparatus adopting the separation method by air injection, for example, Japanese Patent Laid-Open No. 3-2
The "sheet feeding device" disclosed in No. 72932 is generally known. FIG. 10 is a side view showing the configuration of the conventional sheet feeding device. FIG. 11 is a plan view of a main part of the sheet feeding device. And in FIG.
In this sheet feeding apparatus, a perspective view of a support tray 703 as a sheet stacking unit on which recording sheets 702 are stacked is shown. As described above, the sheet feeding device shown in these figures has a configuration in which the recording paper 702 on the lowermost surface among the recording papers 702 stacked on the sheet stacking unit is separated and fed one by one. To be adopted.

The sheet feeding apparatus shown in these figures includes a support tray (sheet stacking means) 703 on which recording sheets 702 are stacked. Then, the support tray 70
3, a lateral regulation member (not shown) that regulates a side surface position (a position in the width direction) orthogonal to the feeding direction of the stacked recording sheets 702, and a rear edge regulation that regulates a rear end position of the recording sheets 702. A member 711 is provided. Further, the support tray 703 is provided on the downstream side of the recording paper 702 in the feeding direction (arrow Q
A cutout 704 is formed near the center in the width direction of the support tray 703.

Then, as shown in FIG. 10, a pair of feed belts 707 having a large number of through holes are arranged below the support tray 703 so that the feed belts 707 are exposed from the notches 704. Rotating rollers 705, 706
It is stretched over. The notch 704 is provided between the rotating rollers 705 and 706 via the feeding belt 707.
The intake duct 708 facing the above is disposed. Then, the recording paper 702 on the support tray 703 is attached to the intake duct 70.
8 is vacuum-sucked to the feeding belt 707 and is driven by the rotating rollers 705 and 706.
7, the recording paper 702 is fed in the feeding direction (Q direction in FIG. 10).

On the other hand, the recording paper 702 on the support tray 703.
There is a possibility that a plurality of sheets will be adsorbed on the feeding belt 707 at the same time, and the adsorbed sheets will be fed on the feeding belt 707 at the same time. Therefore, as shown in FIG. 11, an air injection duct 709 is provided at a predetermined position on the downstream side above the support tray 703 in the feeding direction, and nozzles 710b to 710e parallel to the feeding direction (vertical direction in the drawing) and the above A plurality of nozzles 710a, 710f heading toward the center in the width direction
And so as to communicate with each other. As shown in FIG. 12, the support tray 703 includes a base portion 714 extending from the downstream side to the upstream side in the feeding direction, and side wings formed diagonally upward from both widthwise side portions of the base portion 714. Parts 715 and 716.

The air injection duct 7 in the above-mentioned conventional technique.
09 and the support tray 703 are arranged in a positional relationship as shown in FIG. 11, and the nozzles 710a to 710f concentrate the planar air flow near the center position in the width direction of the support tray 703. The state of distribution of the air flow by the air injection duct 709 is as shown by the hatched portion in FIG.

[0009]

In such a conventional sheet feeding apparatus, air is jetted in the direction opposite to the feeding direction of the recording sheets 702 stacked on the support tray 703, and thus the stacked recording sheets 702 are formed. A rear end regulating member 711 that regulates the rear end position is essential (see FIG. 10). for that reason,
When feeding the recording papers 702 of different sizes, the trailing edge regulating member 711 must be moved according to the size of the recording paper 702, which makes the apparatus large and complicated. Further, even if the recording sheets 702 having different sizes are attempted to be fed at the same time, the recording sheets 702 having a small size may move backward, which may cause a sheet separation failure or a sheet feeding failure.

Further, the recording paper 702 is moved in the longitudinal direction (A3, B).
In the case of feeding four sizes, the air jetted from the air jet duct 709 does not reach the trailing edge of the recording paper 702, and two or more sheets are conveyed at once (double feed). "Double feed") is likely to occur. In order to prevent this double feed, it is conceivable to increase the wind pressure and air volume of the air flow of the air injection. However, when the wind pressure and the air volume increase, the number of rotations of the blower for generating the air flow increases, which causes a problem that noise increases.

Therefore, an object of the present invention is to inject an airflow to one side of the stacked sheets in the feeding direction without increasing noise, and to float the stacked sheets to eliminate separation defects and feeding defects. At the same time, by controlling the feeding of only the stacked sheets other than the separated lowermost sheet to prevent the sheets from shifting, only the separated lowermost sheet is fed to avoid the double feeding of the sheets. Another object of the present invention is to provide a sheet feeding device and an image forming apparatus capable of reliably feeding a sheet while preventing separation defects and feeding defects.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and intersects with a sheet stacking unit for stacking a plurality of sheets and a sheet feeding direction on the sheet stacking unit. Side regulating means for regulating the position in the direction, a feeding means for vacuum-adsorbing and conveying the lowermost sheet of the sheets stacked on the sheet stacking means, and one side portion in the sheet feeding direction. A sheet feeding apparatus, comprising: a floating unit that blows air onto a sheet to float the stacked sheet; and a leading edge regulation unit that regulates a feeding leading end portion of the loaded and floated sheet. is there.

Further, it is preferable that the height between the lowermost portion of the leading end regulating means for regulating the sheet and the sheet supporting surface of the sheet stacking means can be adjusted.

Further, an elevating means for elevating and lowering the leading end regulating means, and a control means for controlling the elevating means according to any one of weight, size and thickness of the sheet to be fed to adjust the height. Is preferred.

The elevating means may be a stepping motor, and the height may be adjusted by rotating the stepping motor in steps corresponding to the sheet to be fed.

Further, from the time when the leading edge regulating means stacks the sheets on the sheet stacking means to the time when the sheets are floated, the lowermost portion that regulates the sheets is the sheet supporting surface of the sheet stacking means. It is even better to maintain the position in a range lower than the sheet supporting surface from substantially the same height.

Further, it is preferable that the floating means injects air from one side portion of the sheet toward the downstream side in the oblique sheet feeding direction.

An image forming apparatus is provided with the above-described sheet feeding device and an image forming means for forming an image on a recording sheet fed from the sheet feeding device.

Further, there is provided an image reading apparatus including the above-mentioned sheet feeding apparatus and an image reading means for reading an image of a document sent from the sheet feeding apparatus.

[Operation] When the air jetted from the floating means hits the sheet stacking means and is blown to the side surface of the stacked sheets, the stacked sheets including the lowermost sheet are floated in a bundle. When the lowermost sheet is adsorbed by the feeding means by the floating of the stacked sheets (floating form), the space between the stacked sheets and the lowermost sheet expands, so that the stacked sheets of the lowermost sheet of the stacked sheets are expanded. The separability from is improved. Further, the leading edge regulating means for regulating the feeding leading end portion of the stacked and floated sheets changes the height of the lowermost portion to regulate the feeding of only the stacked sheets other than the separated lowermost sheet. The sheet is prevented from being conveyed and displaced, and only the separated lowermost sheet is fed. Therefore, it is possible to avoid the double feeding of the sheets, prevent the separation failure and the sheet feeding failure, and ensure the sheet feeding.

The leading edge regulating means regulates all of the stacked sheets until the sheets are stacked on the sheet stacking means and before the sheets are floated, and the lowermost portion for regulating the sheets is: It is at the same height as the sheet supporting surface of the sheet stacking means, or at a position lower than the sheet supporting surface of the sheet stacking means. Then, when the stacked sheets are floated by the floating means, the leading edge regulating means rises above the above-mentioned position, and the above-mentioned separated bottom surface is placed between the lowermost portion of the leading edge regulating means and the sheet stacking means. A gap for conveying the sheet on the side is formed.

Further, when an image is formed on the basis of the original set on the image forming apparatus, the image is formed on the recording paper of the separated and fed sheet.

Then, the separated and fed sheet original is read by the image reading means of the image reading device,
Form an image.

[0024]

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

FIG. 6 is a perspective view of the sheet feeding apparatus 110 showing the embodiment of the present invention. Further, FIG. 7 is a side sectional view of the sheet feeding apparatus 110. And
FIG. 1 is a front view of the sheet feeding device 110 (a front view seen from the right direction (paper feeding direction) in FIG. 7). Further, FIG.
FIG. 3 is a plan view of the sheet feeding device 110. In these drawings, the sheet feeding device 110 is arranged on the sheet tray (sheet stacking unit) 100 on which the sheets S are stacked and the lower surface of the sheet tray 100 on the upstream side in the sheet feeding direction, and is disposed on the lowermost surface of the stacked sheets S. Air is ejected toward the widthwise direction (direction orthogonal to the feeding direction) side end surface of the feeding means 101 for adsorbing and conveying the sheet Sl and the sheet S stacked on the sheet supporting surface of the sheet tray 100. A nozzle (floating means) 105 and a pair of side regulating members 120 and 121 as side regulating means for regulating the width direction side end surface (side surface) of the stacked sheets S are provided.

The feeding means 101 includes a plurality of rotating rollers 103a, 103b, 103 on the lower surface side of the sheet tray 100.
c is arranged, and the rotating rollers 103a, 103b, 10
A feeding belt 104 having a large number of through holes is stretched around 3c. Then, the rotating rollers 103a and 103
An intake duct 102 having an opening that opens upward in FIG. 7 is arranged in the space between b. The intake duct 102 vacuum-adsorbs the lowermost sheet S1 of the sheets stacked on the sheet tray 100 through a large number of through holes of the feeding belt 104. As a result, the sheet vacuum-adsorbed on the feeding belt 104 is fed and conveyed by the rotational driving of the rotating roller 103a. The rotating roller 103a is rotated by a driving means such as a motor (not shown). The intake duct 102 is connected to a compressor or the like (not shown).

The sheet tray 100 includes a tray 100c on which a rear end of the stacked sheets S is placed in the sheet feeding direction,
The tray 100a has an inclined surface orthogonal to the paper feeding direction, and the tray 100b is parallel to the sheet suction surface of the paper feeding means 101. Therefore, in the sheet tray 100, the tray 100c, the tray 100a, and the tray 100b form a concave portion 100 ₁ orthogonal to the sheet feeding direction on the horizontal placement surface of the stacked sheets S. Incidentally, the recess 100 _1, 2 mm to 5 mm maximum deep part with respect to the sheet stacking surface 100c
It is formed to be low (positioned downward in FIG. 7), which stabilizes the sheet separating and feeding operations.

The nozzle 105 directs the air flow to the tray 100b.
After spraying, the passes through the recess 100 ₁ formed in the tray, contents are arranged so blown into the paper feeding direction forward.

Next, the operation of sheet feeding in the sheet feeding device 110 will be described.

The sheets S stacked on the tray are slightly floated from the recess 100 ₁ toward the front in the sheet feeding direction by the air flow ejected from the nozzles 105, as shown in FIG. At the same time, only the lowermost sheet S1 of the stacked sheets S is sucked by the sheet feeding means 101 to cause the sheet tray 10 to move.
It deforms along the concave portion 100 ₁ provided at 0. The air flow from the nozzle 105 enters the gap between the lowermost sheet S1 thus formed and the sheet immediately above it, and the sheet S1 and the sheet immediately above are separated by the air layer. Here, the feeding belt 1
The separation / conveyance operation is performed by adding rotational drive to 04. When the lowermost sheet S1 of the stacked sheets S is attracted by the feeding means 101, the lowermost sheet S1 is peeled off from the other stacked sheets S, and the peeled lowermost sheet S1 is placed on the sheet tray 100. Formed recess 10
A space is created between the stacking sheet S and the lowermost sheet S1 by closely adhering to 0 ₁ . When air is ejected from the nozzles 105 toward this space, the stacked sheets S float, and the friction between the stacked sheets S and the lowermost sheet S1 is reduced, so that the lowermost sheet S1 can be easily fed and conveyed. can do.

On the other hand, a cutout portion 100d that faces (exposes) the feeding belt 104 of the above-described feeding means 101 is provided on the slope 100b upstream of the sheet tray 100 in the feeding direction.
(FIG. 4) is provided. Slope 10 of the sheet tray 100
0b and the feeding belt 104 are as follows: the feeding belt 104 is parallel to the surface of the slope 100b, and the feeding belt 104 is the slope 1
00b and at least substantially on the same plane, and more preferably on the same plane and projecting by about 2 mm.

Further, as shown in FIG. 7, the feeding belt 104 is wound around the rotating rollers 103a, 103b, 103c in a substantially "V" shape so that the right end portion of the feeding belt 104 is closer to the tip end side of the slope 100b. Is also located below and functions to form a separated space between the front end surface of the stacked sheets S (the right end in FIG. 7) and the lowermost sheet S1. By exhausting the air jetted from the nozzle 105, this space exerts a rectifying effect on the air and prevents flapping of the sheet due to the blown air.

Further, the feeding belt 104 of the feeding means 101
The positional relationship between the sheet and the end surface on the sheet side is preferably 3 mm to 10 mm on the opposite side of the nozzle 105. The relationship is
When the lowermost sheet S1 is adsorbed to the feeding belt 104, the range is such that fluttering due to air blowing from the nozzle 105 does not occur.

Next, the side regulating means provided on the sheet tray 100 will be described. The side restricting member 121 as the side restricting means restricts the side end portion of the stacked sheets S at a position facing the nozzle 105.
A holding member 123 that holds the stacked sheets is provided substantially at the center of the side regulating member 121. The holding member 123 is
For example, an elastic member such as a sponge is used, and by pressing the side end surface of the stacked sheets S to apply resistance, movement of the sheets S in a bundle in the feeding direction, double feeding, and takeout are prevented. The side regulating member 121 is attached to the sheet tray 100 so that the position of the sheet in the width direction (direction orthogonal to the sheet feeding direction) can be adjusted according to the size of the sheet to be fed.

On the other hand, the side regulating member 120 as the side regulating means located on the nozzle 105 side is the tray 100.
A convex portion 124 that is fixed to a predetermined position above and abuts a part of the stacked sheets S is provided. The convex portion 124 is, for example,
A rib-shaped member punched from the side regulating member 120 may be used. The convex portions 124 are provided so as to lift up the side edges of the stacked sheets S and to facilitate the air flow from the air injection nozzle 105 to enter the lower surface side of each rolled up sheet S.

Next, the nozzle 105 will be described with reference to FIGS.
This will be described with reference to FIG. The air injection nozzle 105
Is provided with an air injection opening at a position separated from the side edge of the stacked sheets S (left edge in the figure) by a predetermined distance (10 mm to 50 mm). As shown in FIGS. 3 and 5, the nozzle 105 is arranged at an angle θ (30 ° to 60 °), and the jetted air flow is blown onto the surface of the sheet tray 100 as indicated by the arrow in the figure. After being blown, the blown airflow is directed toward the side edge of the stacked sheets S. Therefore, the rectified airflow hits the stacked sheets S, and the sheets S are reliably separated one by one.

Further, in the nozzle 105, as shown in FIG. 4, the air flow injection opening (direction of the injected air flow) is from the upstream side of the sheet feeding direction to the downstream side of the sheet feeding direction with respect to the sheet feeding direction. It is arranged at an angle α so as to cross diagonally toward the side. In this way, by inclining the nozzle 105 by the angle α, the airflow ejected from the nozzle 105 flows from the central portion of the sheet feeding apparatus 110 to the downstream side in the feeding direction. Therefore, the sheet tray 10
It is possible to prevent the sheets S stacked on the sheet 0 from being locally lifted up, and to prevent the sheets S from flapping, so that the sheets can be reliably separated and fed.

Therefore, the sheet feeding device 110 described above.
The sheet can be fed regardless of different sheets (size, thickness, etc.) by injecting air from one end side of the sheet toward the feeding unit 101. However, since air is jetted from one end side of the sheet, the remaining stacked sheets S that have separated the sheet S1 before the sheet S1 separated from the stacked sheet S, especially the bottom of the stacked sheets S, are conveyed. Since the sheet position of the sheet S2 (FIG. 7) becomes unstable due to the force of the air jet, and the sheet S2 moves, the separated sheet S1 and the bottom sheet S2 are Rarely double feeds are being conveyed at the same time.
Therefore, an air flow is jetted to one side portion of the stacked sheet S in the feeding direction to levitate the stacked sheets to eliminate separation failure and paper feeding failure, and only the stacked sheets other than the separated bottommost sheet are separated. By restricting feeding to prevent sheet misalignment, only the separated lowermost sheet is fed to avoid double feeding of sheets and prevent sheet separation failure or sheet feeding failure. The configuration of the sheet feeding device partially modified to ensure reliable feeding will be described below with reference to FIGS. 1 to 5.

In FIG. 1, reference numeral 500 denotes a leading edge regulating means (hereinafter referred to as "leading edge regulating member") which regulates the feeding leading edge of the stacked sheets to prevent the sheets from being displaced. As shown in FIGS. 1 and 3, the tip regulation member 500 includes a shaft 501.
Are supported so as to be rotatable around the fulcrum. Pulley 502
Is integrally connected to the tip regulation member 500,
The torque of the stepping motor 503 is applied to the motor pulley 50.
4, through the timing belt 505 and the pulley 502, it can be transmitted to the tip regulation member 500. The home position sensor 506 detects the reference rotation angle phase by detecting the detection flab 500a of the tip regulation member 500. By controlling the stepping motor 503 based on the detection signal from the home position sensor 506, the tip regulation member 5
The height of 00, that is, the gap G shown in FIGS. 2, 3, and 5 can be freely adjusted.

That is, after the home position sensor 506 detects the detection flag 500a, the stepping motor 503 is rotated by the number of pulses according to any one of the weight, size, thickness, etc. of the sheet S to be fed, and the leading end is rotated. Regulating member 50
Adjust the height of 0 (gap G). For example, when the weight of the sheet S is heavy, the size is large, or the sheet S is thick, it is difficult to lift the sheet S, so that the gap G is made small to prevent double feeding, and the sheet is light, the size is small, or the sheet is thin. Since the sheet is easily lifted up, it is preferable to increase the gap G so that the sheet to be fed is not caught by the leading edge regulating member 500.

As shown in FIG. 5, until the sheets S are stacked on the sheet tray 100 and the stacked sheets S are floated, the lowermost surface of the leading edge regulating member 500 is positioned on the surface of the sheet tray 100. are doing. At this time, the gap G is zero. The lowermost surface of the leading edge regulating member 500 may be located below the surface of the sheet tray 100. Then, when the stacked sheets S are floated by the airflow injection pressure from the nozzle 105, the leading end regulating member 500 starts the opening operation and forms the gap G.
The stacked sheet S receives a force upstream in the sheet feeding direction due to the airflow injection pressure inclined by the angle α (α), but the floating stacked sheet (not including the lowermost sheet S1) is moved by the leading edge regulating member 500. It becomes impossible to move.

Since the lowermost sheet S1 is vacuum-sucked to the feeding belt 104 as described above, it can be conveyed through the gap G below the lower end surface of the tip regulating member 500. Therefore, depending on the weight, size, thickness, etc. of the stacked sheets S, the size of the gap G shown in FIG. By setting the optimum value, only the lowermost sheet S1 can be reliably conveyed from the gap G.

Next, the operation of the present invention will be described with reference to FIGS. 2, 3 and 5.

First, FIG. 5 shows a state in which the sheets S are stacked on the sheet tray 100. Until the stacked sheets S are floated, the lowermost surface of the leading edge regulating member 500 is located on the surface of the sheet tray 100.
At this time, the gap G is zero. Thus, the gap G
By setting 0 to 0, it is possible to prevent the lower sheet from shifting to the downstream side through the gap G when the sheets are stacked, the tip of the sheet bundle is regulated straight, and sheets other than the sheet to be sent are surely secured. It is regulated by the tip regulation member 500. FIG. 2 shows the lowermost sheet S1 of the stacked sheets S.
1 is a sectional view showing a state in which the stacked sheets S are fed from a recess 100 ₁ (FIG. 2) provided in the sheet tray 100 by an air flow (indicated by a dashed arrow in FIG. 1) from the nozzle 105 according to FIG. It is slightly floating toward the front in the paper direction. Further, the stacked sheets S1 are deformed by the suction of the sheet feeding means 101 along the concave portions 100 ₁ provided in the sheet tray 100.

Then, the air (flow) from the nozzle 105 enters the space between the lowermost sheet S1 thus formed and the sheet immediately above it, and the air (flow) separates the sheet S1 and the immediately above sheet. When the stacked sheets S are floated by the airflow injection pressure from the nozzles 105, the leading edge regulating member 500 starts the opening operation by the stepping motor 503, and rotates to a state in which a gap G shown in FIG. A gap G is formed. The stacked sheets S (not including the lowermost sheet S1) receive a force upstream in the sheet feeding direction due to the airflow injection pressure inclined by the angle α, but since they are floating, they are regulated by the leading edge regulation member 500 and moved. It is in the impossible state and is prevented from being conveyed in the direction of the conveying rollers 1 and 2 (rightward in the drawing).

Then, only the separated and conveyed sheet S1 is adsorbed and conveyed by the feeding belt 104 in the gap G below the leading edge regulating member 500, whereby the separating and conveying operation is performed. The separated and conveyed sheet S1 passes through the paper feed sensor lever 3 by the guide member 4 and is pulled out by the conveying rollers 1 and 2.

Next, the sheet feeding device 1 of the present invention described above.
An image forming apparatus (copier) having the configuration of 10 will be described with reference to the sectional view of FIG.

As shown in the figure, an image forming apparatus (hereinafter referred to as “apparatus body”) 200 includes a document placing table 206, a light source 207, an optical system 208, a paper feeding section 209, and an image forming section (image forming means) 202. Etc. are arranged. Paper feed unit 209
Has a paper feed tray 210, a cassette 211, and a paper deck 213. The image forming unit 202 is provided with a photoconductor 214, a developing device 215 containing a toner, a transfer charging device 216, a separation charging device 217, a cleaner 218, a primary charging device 219, and the like. Image forming unit 2
On the downstream side of 02, the conveying unit 220, the fixing device 204,
Discharge rollers 205 and the like are provided.

In this image forming apparatus, when a sheet feeding signal is output from a controller (not shown) provided in the apparatus main body 200, the sheet S is fed from the sheet feeding tray 210, the cassette 211 or the paper deck 213. It On the other hand, the light radiated from the light source 207 to the original placed on the original placing table 206 and reflected is condensed on the photoconductor 214 via the optical system 208. The photoconductor 214 is charged in advance by a primary charger 219, and an electrostatic latent image is formed by light reflected from a document, and then a toner image is formed by a developing device 215.

The sheet S fed from the sheet feeding section 209 is
The skew feeding is corrected by the registration roller 201, and the timing is adjusted to be sent to the image forming unit 202. In the image forming unit 202, the transfer charger 216 transfers the toner image on the photoconductor 214 to the sent sheet S, and the transferred sheet S is separated from the transfer charger 216 by the separation charger 217. Photosensitive member 2 charged with polarity
Separated from 14. Then, the separated sheet is conveyed to the fixing device 204 by the conveying device 220, and the unfixed transfer image is permanently fixed by the fixing device 204. The sheet S on which the image has been fixed is discharged out of the apparatus main body 200 by the discharge roller 205.

On the other hand, in the case of double-sided copying or multiplex copying, the sheet copied on one side is discharged in the direction of arrow F on the sheet tray 100 of the sheet feeding apparatus 110 according to the above-described embodiment. Then, the sheet tray 100
As described above, the sheets stacked on the sheet are reliably separated one by one from the lowest sheet, re-fed, and sent from the registration roller 201 to the image forming unit 202 to be copied again. . As a result, first, the paper feeding unit 209
The sheet S fed from is subjected to double-sided copying or multiple copying and is discharged to the outside of the apparatus main body 200.

The present invention is not limited to the above embodiment, but may be applied to, for example, an automatic document feeder (ADF) for automatically feeding a document. As the above-described automatic document feeder, for example, as shown in FIG. 8, a document tray 300 on which a document is placed, a sheet feeding device 301 to which the present invention is applied, and a sheet feeding device 301 A transport belt 302 for sandwiching and transporting a document sent from the tray 300 with a document placing table 206,
It may be roughly configured by a discharge tray 303 on which a document having an image read by a document reading unit configured by a light source 207, an optical system 208, and the like is stacked.

Next, an embodiment in which the tip regulating member is changed will be described with reference to FIG.

As shown in FIG. 9, the tip regulating member 510
Is rotatably supported about a shaft 511, and one end of the tip regulating member 510 forms an unevenness 510 ', and a part of the leaf spring 512 enters the groove of the recess, and at that position, The tip regulation member 510 is fixed. For example, when the tip regulating member 510 is rotated with a finger or the like, the leaf spring 512 is rotated.
Can enter the groove of the next concave portion while elastically deforming, and change the position of the tip regulating member 510 in the height direction stepwise.

In this embodiment, the unevenness 5 of the tip regulating member 510 is
10 'according to the sheet size index (A3, B4, A
4, B5) are provided, and the leaf spring 512 is set so as to match the recess of the index of the size of the sheet S to be used. The index may be the weight or thickness of the sheet S.

In the above structure, the user manually switches the height of the leading edge regulating member 510 according to the weight, size, thickness or the like of the stacked sheets S,
The optimum gap G can be adjusted, and reliable sheet separation / feeding becomes possible.

The present invention is not limited to the above embodiment, but instead of the leaf spring 512, a spherical member fitted in the groove of the recess, and the spherical member attached to the groove of the recess. It may be constituted by a coil spring that is biased to abut.

[0058]

As described above, according to the present invention, air is jetted to one side portion in the feeding direction of stacked sheets,
The separated lowermost surface is prevented by floating the stacked sheets to eliminate separation failure and paper feeding failure, and restricting the feeding of only stacked sheets other than the separated lowermost sheet to prevent the sheets from shifting. Only the sheet on the side is fed to avoid double feeding of the sheets, and it is possible to reliably feed sheets by preventing separation defects and feeding defects, thus preventing jams and improving the reliability of the device. It can be dramatically improved.

Further, depending on the sheet feeding apparatus of the present invention, air is jetted from one end side of the stacked sheets toward the sheet feeding means, so that the lowest sheet and the other sheets (sheets, size, tsubo) The sheet can be separated regardless of the type, quantity, and thickness, and the separated lowest sheet can be reliably fed by the feeding means, and the double feeding of sheets can be effectively prevented.

Since the image forming apparatus of the present invention is provided with the above-mentioned structure, it is possible to form an image based on the document of the separated sheets without fail, so that omission of image formation or the like can be avoided. Therefore, the reliability of the image forming apparatus can be further improved.

Further, since it is possible to form an image on the recording sheets of the separated sheets with certainty, it is possible to avoid jamming due to the feeding of a plurality of recording sheets, and the reliability of the image forming apparatus is remarkably improved. Can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of an entire sheet feeding device embodying the present invention.

FIG. 2 is a side sectional view of a sheet feeding device embodying the present invention.

FIG. 3 is a front view of the same.

FIG. 4 is a plan view of the same.

FIG. 5 is a front view of the sheet feeding device showing a state where the leading edge regulating member is completely lowered.

FIG. 6 is a perspective view of the entire sheet feeding device.

FIG. 7 is a front sectional view of the same.

FIG. 8 is a sectional view of the image forming apparatus according to the present invention.

FIG. 9 is a front view of the sheet feeding device in which the leading edge regulating member is partially changed.

FIG. 10 is a side sectional view of a conventional sheet feeding device.

FIG. 11 is a plan view (top view) of a main part of a conventional sheet feeding device.

FIG. 12 is a perspective view of a tray in a conventional sheet feeding device.

FIG. 13 is an explanatory view of air flow distribution in the conventional sheet feeding apparatus.

[Explanation of symbols]

100 Sheet Stacking Means (Sheet Tray) 101 Feeding Means 105 Floating Means (Nozzles) 110 Sheet Feeding Devices 120 Side Restricting Means (Side Restricting Members) 121 Side Restricting Means (Side Restricting Members) 200 Image Forming Apparatus (Device Main Body) ( Image reading device) 202 Image forming means (image forming part) 207 Image reading means (light source) 208 Image reading means (optical system) 500 Tip regulation means (tip regulation member) 503 Lifting means (stepping motor) 510 Tip regulation means (tip) Restriction member) S sheet (stacked sheet) S1 Bottom sheet

Claims (8)

[Claims] 1. A sheet stacking unit for stacking a plurality of sheets, a side restricting unit for restricting a position of the sheet stacking unit in a direction intersecting a sheet feeding direction, and a side stacking unit stacked on the sheet stacking unit. A feeding unit that vacuum-adsorbs and conveys the lowermost sheet of the sheets, a levitation unit that injects air to one side portion of the sheet in the feeding direction and floats the stacked sheets, and the stacking unit. A sheet feeding device comprising: a leading edge regulating unit configured to regulate a feeding leading edge portion of a sheet that has floated up. 2. The sheet feeding according to claim 1, wherein a height between a lowermost portion of the leading end regulating means for regulating the sheet and a sheet supporting surface of the sheet stacking means is adjustable. apparatus. 3. Elevating means for elevating and lowering the leading edge regulating means, and control means for controlling the elevating means according to any one of weight, size and thickness of a sheet to be fed to adjust the height. The sheet feeding apparatus according to claim 2, further comprising: 4. The sheet feeding apparatus according to claim 3, wherein the elevating means is a stepping motor, and the height is adjusted by rotating the stepping motor in steps corresponding to the sheet to be fed. 5. The lowermost part that regulates the sheet is the sheet supporting surface of the sheet stacking means from the time when the leading edge restricting means stacks the sheet on the sheet stacking means to the time when the sheet is floated. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is maintained at a position in a range lower than the sheet supporting surface from substantially the same height. 6. The sheet feeding according to claim 1, wherein the floating means injects air from one side portion of the sheet toward a downstream side in a diagonal sheet feeding direction. apparatus. 7. A sheet feeding device according to claim 1, and an image forming unit for forming an image on a recording sheet fed from the sheet feeding device. An image forming apparatus characterized by the above. 8. A sheet feeding apparatus according to claim 1, and an image reading unit for reading an image of a document sent from the sheet feeding apparatus. Image reading device.