JPH09194061A - Paper sheet feeding device and image forming device having the paper sheet feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet feeding device to reliably separate a lowermost paper sheet from other paper sheets thereabove and prevent the occurrence of the double feed of paper sheets. SOLUTION: An end part suction member 130 is arranged at one side part of a paper sheet against which air is jetted through a nozzle 105. The end part suction member 130 constantly sucks one side part of a paper sheet during the feed of paper sheets, and air jetted through the nozzle 105 is prevented from entering a position below a lowermost part S1, This constitution reliably separates the lowermost paper S1, sucked on the feed belt 104 side and the end part suction member 130 side, away from a paper sheet S2 situated next to and above the lowermost paper, by means of air jetted through the nozzle 105.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an image forming apparatus such as a copying machine, a printer or a facsimile, and separates a plurality of sheets such as a plurality of originals or recording sheets stacked on a sheet stacking unit one by one. The present invention relates to a sheet feeding device for feeding.

[0002]

2. Description of the Related Art A recycle type automatic document feeder (RDH) for reading an image of a sheet-like document sent from a sheet stacking unit and returning the document to the top of the sheet on the sheet stacking unit again. An image forming apparatus such as a copying machine or other various printing devices and printing devices provided with the above-mentioned copying machine includes sheets of originals and recording sheets stacked on the sheet stacking unit.
A sheet feeding device that feeds the sheets located on the lowermost surface separately from other sheets one by one and feeds the sheets.

In such a sheet feeding apparatus, as means for separating sheets one by one, a separation method by air jetting, a separation method by a separation claw, a separation method by a roller rotating in the reverse direction to the sheet feeding direction, and the like are used. is there.

Among these, a sheet feeding apparatus adopting a separation method by air injection is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-27.
A "sheet feeding apparatus" disclosed in Japanese Patent No. 2932 is generally known. Also, as a configuration similar to this, U.S. Pat. No. 3,198,514 (corresponding Japanese application; Japanese Patent Publication No. 55-19857) is known.

FIG. 9 is a side view showing the structure of the above-mentioned conventional sheet feeding apparatus. Further, FIG. 10 is a plan view of an essential part of the sheet feeding device. Further, FIG. 11 is a perspective view of the support tray 3 as a sheet stacking unit on which the recording papers 2 are stacked in this sheet feeding apparatus. As described above, the sheet feeding device shown in these figures has a configuration in which the recording papers 2 on the lowermost surface of the recording papers 2 stacked on the sheet stacking unit are separated and fed one by one. To be adopted.

The sheet feeding apparatus shown in these figures has a support tray (sheet stacking means) 3 on which recording sheets 2 are stacked.
It has. Then, on the support tray 3, there are provided a lateral regulating member (not shown) for regulating a side surface position (widthwise position) orthogonal to the feeding direction of the stacked recording papers 2, and a rear end position of the recording papers 2. A rear end regulating member 11 for regulating is provided. A notch 4 is formed on the downstream side of the support tray 3 in the feeding direction of the recording paper 2 (arrow G side in FIG. 9) and near the center of the support tray 3 in the width direction.

As shown in FIG. 9, a pair of feeding belts 7 having a large number of through holes are arranged below the support tray 3 so that the feeding belt 7 is exposed from the notch 4. It is stretched around the rotating rollers 5 and 6.

An intake duct 8 facing the notch 4 via the feeding belt 7 is arranged between the rotating rollers 5 and 6. Then, the recording paper 2 on the support tray 3 is vacuum-sucked to the feeding belt 7 by its suction duct 8, and the recording paper 2 is moved in the feeding direction by the feeding belt 7 which is driven and driven by the rotating rollers 5 and 6. It is fed in the direction G in FIG. 9).

On the other hand, a plurality of recording papers 2 on the support tray 3 may be simultaneously adsorbed by the feeding belt 7, and the adsorbed plural sheets may be simultaneously fed by the feeding belt 7. . Therefore, as shown in FIG.
An air injection duct 9 is provided at a predetermined position on the downstream side above in the feeding direction, and the nozzle 1 is parallel to the feeding direction (vertical direction in the drawing).
0b to 10e are provided so as to communicate with the plurality of nozzles 10a and 10f heading toward the center in the width direction. As shown in FIG. 11, the support tray 3 has a base portion 14 extending from the downstream side toward the upstream side in the feeding direction.
And side wings 15 and 16 which are formed obliquely upward from both widthwise side portions of the base portion 14.

The air injection duct 9 and the support tray 3 of this conventional example are arranged in a positional relationship as shown in FIG. 10, and a flat air flow is generated by the nozzles 10a to 10f near the center position in the width direction of the support tray 3. I try to concentrate. The state of distribution of the air flow by the air injection duct 9 is as shown by the hatched portion in FIG.

[0011]

In such a conventional sheet feeding apparatus, air is jetted in the direction opposite to the feeding direction of the recording papers 2 stacked on the support tray 3, so that the loaded recording papers 2 are ejected. The rear end regulating member 11 that regulates the rear end position is essential (see FIG. 9). Therefore, different size recording paper 2
When the sheet is fed, the trailing edge regulating member 11 has to be moved according to the size of the recording paper 2, which makes the apparatus large and complicated. Further, even if the recording papers 2 having different sizes are fed at the same time, the recording papers 2 having a small size may move backward.

Further, when a recording paper or an original having a curl (upper and lower) on the leading end side in the paper feeding direction is fed, an air flow caused by air jet hits the curl portion, which may cause separation failure or feeding failure. was there.

Further, when the recording paper 2 is fed in the longitudinal direction (longitudinal length of A3, B4 size), the air jetted from the air jet duct 9 does not reach the rear end portion of the recording paper 2 and is heavy. Sending 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 wind pressure and air volume increase,
The number of rotations of the blower for generating air flow increases,
It causes a problem that the noise becomes loud.

Therefore, according to the present invention, the sheet size or the type of sheet (basis weight, thickness), the sheet leading end side in the sheet feeding direction of the sheet stacked on the support tray is not regulated, and the trailing end in the sheet feeding direction is controlled. An object of the present invention is to provide a sheet feeding apparatus that can reliably feed a sheet without causing a paper feeding failure regardless of the presence or absence of curl, and an image forming apparatus including the sheet feeding apparatus.

[0015]

According to a first aspect of the present invention, there is provided a sheet stacking unit for stacking a plurality of sheets, and a side for regulating the position of the sheet on the sheet stacking unit in a direction orthogonal to the sheet feeding direction. Regulating means, a feeding means for vacuum-adsorbing and conveying the lowermost sheet among the sheets stacked on the sheet stacking means, and injecting air to one side of the sheet on the sheet stacking means, Separation means for separating the sheet vacuum-adsorbed by the feeding means from other sheets,
And an end portion suction means for sucking the vicinity of one side portion of the lowermost sheet of the sheets to the sheet stacking means side.

According to the second aspect of the invention, the frictional resistance acting between the end suction means and the sheet is made smaller than the frictional resistance acting between the feeding means and the sheet. It has a feature.

According to a third aspect of the present invention, the suction surface of the end suction means contacting the sheet is substantially flush with the suction surface of the feeding means contacting the sheet. The sheet feeding device according to claim 1, wherein the sheet feeding device has a friction coefficient smaller than that of the suction surface of the means.

Further, the invention according to claim 4 is characterized in that the sheet suction force of the end suction means is smaller than the sheet suction force of the feeding means.

The invention according to claim 5 is characterized in that the end suction means always sucks the sheet regardless of whether the sheet suction of the feeding means is on or off.

Further, the image forming apparatus of the present invention comprises any one of the above-mentioned sheet feeding apparatus and an image forming means for forming an image on a sheet fed from the sheet feeding apparatus. It has a feature.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment of the Invention) FIG. 1 is a perspective view of a sheet feeding apparatus 110 showing a first embodiment of the present invention.
Further, FIG. 2 is a side sectional view of the sheet feeding apparatus 110. 3 is a front view of the sheet feeding device 110 (a front view seen from the right direction (paper feeding direction) in FIG. 2). Further, FIG. 4 is a plan view of the sheet feeding device 110.

In these figures, the sheet feeding device 11
0 is a sheet tray (sheet stacking unit) 100 on which the sheets S are stacked, and is arranged on the upstream side of the lower surface of the sheet tray 100 in the feeding direction, and the lowermost sheet S of the stacked sheets S is arranged.
A sheet feeding means 101 for adsorbing and conveying 1 and a sheet tray 10.
Nozzles (separating means) 105 for injecting air toward the width direction (direction orthogonal to the feeding direction) side end surface of the sheet S stacked on 0, and the width direction side end surface (side surface) of the stacked sheets S
And a pair of side regulating members 120 and 121 as side regulating means for regulating the.

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. 2 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 connected to a driving means such as a motor (not shown). Further, the intake duct 102 is connected to a compressor or the like (not shown).

The sheet tray 100 has a sheet stacking surface 100c on which sheets S are stacked, and an inclined surface 100a inclined downward from the end of the sheet stacking surface 100c in the sheet feeding direction in FIG.
And from the lowermost end of the slope 100a to the downstream side in the feeding direction (see FIG.
It is configured with a slope 100b that rises toward the middle right side). It should be noted that it is desirable that the tip of the slope 100b (the right end in FIG. 2) be higher than the horizontal plane of the sheet tray stacking surface 100c.

The purpose of making the tip end of the above-mentioned slope 100b higher than the sheet stacking surface 100c is to feed the lowermost sheet S1 and to feed the lowermost sheet S1 and to stack the stacked sheet bundle. Is to prevent the sheet from moving downstream in the feeding direction. That is, the stacked sheets S
Is to prevent the sheet tray slope 100b from moving downstream in the feeding direction.

The sheet tray 100 has a slope 10
0a and the slope 100b, the recess 100 _{1 on the} sheet stacking surface.
Is formed. The recess 100 ₁ maximum deep part 2mm~5mm lowered with respect to the sheet stacking surface 100c (FIG. 2
It is formed so as to be positioned in the middle lower part), thereby stabilizing the sheet separating and feeding operations.

Here, the maximum depth of the recess 100 ₁ is the intersection of the slope 100a and the slope 100b. Further, the stable separation and feeding operation of the sheets means that the lowermost sheet S1 of the stacked sheets S is peeled off from the other stacked sheets S when the lowermost sheet S1 of the stacked sheets S is attracted by the feeding means 101, and the peeling is performed. The lowermost sheet S1 thus formed is the sheet tray 1
00 to be closely attached to the concave portion 100 ₁ formed on the stack sheet S
And a space is formed between the lowermost sheet S1. 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 slope 100b upstream of the sheet tray 100 in the feeding direction, there is provided a notch portion 100d which faces (exposes) the feeding belt 104 of the feeding means 101 described above. The relationship between the slope 100b of the sheet tray 100 and the feeding belt 104 is that the feeding belt 104 has the slope 100b.
It is preferable that the feeding belt 104 is parallel to b and is at least substantially on the same plane as the inclined surface 100b (preferably, it is projected from the same plane to about 2 mm).

Further, as shown in FIG. 2, 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 (the right end in FIG. 2) of the stacked sheets S and the lowermost surface 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.

Furthermore, the positional relationship between the feeding belt 104 and the side end surface of the sheet S is as shown in FIG.
On the side where the is arranged (the left side in FIG. 3), the distance l from the side end surface of the sheet S to the side edge of the feeding belt 104 is 3 m.
It is desirable to set it to m to 10 mm. This feeding belt 10
4 and the side end surface of the sheet S are the lowermost sheet S
When 1 is adsorbed on the feeding belt 104, the nozzle 105
The range in which the sheet S1 does not flap due to the air jetted from

Next, the side regulating means provided on the sheet tray 100 will be described.

The side regulating member 121 as the side regulating means is provided at a position facing the air injection nozzle 105.
The side edges of the stacked sheets S are regulated. 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 made of, for example, an elastic member such as a sponge, and presses the side end surface of the stacked sheets S to apply resistance, thereby preventing movement of the sheets S in a bundle in the feeding direction, double feeding, and removal. To do. In addition, the side regulating member 121, depending on the sheet size to be fed,
It 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.

On the other hand, the side regulating member 120 as a side regulating means located on the air injection nozzle 105 side is provided with a convex portion 124 which is fixed at a predetermined position on the tray 100 and abuts against a part of the stacked sheets S. There is. 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 air injection nozzle 105 will be described with reference to FIGS.

The air injection nozzle 105 has a predetermined distance (10 mm to 50 mm) from the side end (the left end in the drawing) of the stacked sheets S.
mm) away from each other, an air injection opening is provided. As shown in FIG. 3, the air injection nozzle 105 has an angle θ (3
(0 ° -60 °), the jetted airflow is blown onto the surface of the sheet tray 100 as indicated by an arrow in the figure, and then the blown airflow is fed to the sheet S.
It goes to the side edge of. Therefore, the rectified airflow hits the stacked sheets S, and the sheets S are reliably separated one by one.

Further, as shown in FIG. 4, the air jet nozzle 105 has the air flow jet opening portion (the direction of the jetted air stream) from the upstream 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 downstream side in the direction. 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, it is possible to prevent the sheets S stacked on the sheet tray 100 from locally lifting and also to prevent the sheets S from flapping.
It is possible to reliably separate and feed sheets. (Second Embodiment of the Invention) FIGS. 5 to 7 are explanatory views of a second embodiment of the present invention. Of which, Figure 5
6 is a plan view of the sheet feeding device, FIG. 6 is a view in the direction of arrow A in FIG. 5, and FIG. 7 is an operation explanatory diagram of the sheet feeding device according to the present embodiment. In these drawings, the same components as those in FIGS. 1 and 2 of the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

The sheet feeding device 110 according to the second embodiment will be described in detail below.

In these figures, the feeding means 102 is
An intake duct 140 is arranged below the feeding belt 104 having a large number of suction holes in FIG.
The suction fan 142 is attached to the lower end of FIG.
In the intake passage 141 of the intake duct 140, the intake passage 141
A valve 143 that opens and closes is disposed.

The valve 143 and the suction fan 1
The intake duct 140 between the
A duct 131 that branches from 0 and extends upward in FIG. 6 is formed so as to suck the sheet end portion on the nozzle 105 side. At the upper end of the duct 131 in FIG. 6, an end suction member (end suction means) 13 having a large number of suction holes 130a is provided.
0 is attached. This end suction member 130 is
The upper surface is formed to be substantially flush with the upper surface of the conveyor belt, and the width for sucking the sheet is formed to be a predetermined width (for example, about 5 to 20 mm) from the widthwise end portion of the sheet. There is.

As shown in FIG. 6, the feeding belt 104 side is sucked by the suction fan 142 through the intake duct 140, and the suction state is turned on / off by the valve 143 as described above. Has become. On the other hand, the end suction member 130 side is sucked by the suction fan 142 via the duct 131, the suction is not turned on / off, and is always sucked by the suction fan 142 during sheet feeding. There is. The end suction member 1
Since the sheet 30 is fed while sliding on the end suction member 130 while being adsorbed, the sheet is made of a material having a small friction resistance on its surface, or is subjected to a surface treatment so that the coefficient of friction of the surface becomes small. It is desirable to use the above-mentioned one and further chamfer the edge portion of the suction hole 130a.

Next, the operation of the sheet feeding apparatus according to this embodiment will be described.

As shown in FIG. 7A, when the sheet feeding operation is started, first, air is blown from the nozzle 105, and the entire sheet on the sheet tray 100 is floated.

Next, as shown in FIG. 7B, the suction fan 142 (see FIG. 6) is turned on, and the intake duct 140 is turned on.
When suction on the feeding belt 104 side and suction on the sheet end side are started via the duct 131 and the duct 131, the lowest sheet S1 is attracted to the feeding belt 104 and the end suction member 130, and the lowest sheet S1 and the second sheet S2 (other stacked sheets) are separated. And the feeding belt 10
When the sheet 4 is rotationally driven, the sheet S1 is conveyed to the downstream side. At this time, blown air enters between the sheet S1 and the sheet S2, and the sheets above the sheet S2 are floating, so that they are not pulled and fed by the sheet S1. Further, the sheet S1 is conveyed to the downstream side, and the conveying roller 1
When it reaches 09, the sheet S1 is pulled out by the transport roller 109.

Next, as shown in FIG. 7C, the sheet S
When 1 is nipped by the conveyance roller 109, the feeding belt 10
4 and the air suction on the side of the feeding belt 104 are stopped. At this time, since the suction on the end portion side of the sheet and the blowing of the air from the nozzle 105 are still 0N, the end portion in the width direction of the sheet S1 is adsorbed on the tray surface as shown in FIG.
The sheet above the second sheet S2 and the lowest sheet S1
And are separated by the air blown from the nozzle 105. Therefore, the air blown out from the nozzle 105 does not enter below the lowest sheet S1, and only the lowest sheet S1 is pulled out by the transport roller 109.

Therefore, the sheet feeding apparatus according to the present embodiment does not cause a sheet above the second sheet S2 to be double-fed along with the lowest sheet S1 and is stable sheet feeding. It can be performed. Further, the sheet feeding apparatus according to the present embodiment uses the end suction member 130 whose surface has a small friction resistance or is subjected to a surface treatment, and further, the edge portion of the suction hole 130a is Since the sheet is chamfered, even if the sheet slides on the end suction member 130, the resistance that causes the sheet feeding failure does not act, and the sheet is not damaged. (Image Forming Apparatus) Next, an image forming apparatus (copier) including the above-described sheet feeding apparatus 110 of the present invention will be described with reference to the sectional view of FIG.

As shown in the figure, the image forming apparatus main body 200 is provided with a document placing table 206, a light source 207, an optical system 208, a sheet feeding section 209, an image forming section (image forming means) 202 and the like. The paper feed unit 209 includes a paper feed tray 210, a cassette 211, and a paper deck 213.
The image forming unit 202 includes a photoconductor 214, a developing device 215 containing toner, a transfer charger 216, and a separation charger 21.
7, a cleaner 218, a primary charger 219, etc. are arranged respectively. Downstream of the image forming unit 202, a conveying unit 220, a fixing device 204, a discharge roller 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 by the conveying device 2
The sheet 20 is conveyed to the fixing device 204, and the fixing device 204 permanently fixes the unfixed transferred image. 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 multiple 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. (Other Embodiments) The present invention is not limited to the above embodiment, and may be applied to, for example, an automatic document feeder (ADF) for automatically feeding a document.

As this automatic document feeder, for example, as shown in FIG. 8, a document tray 30 on which a document is placed is placed.
0, a sheet feeding device 301 to which the present invention is applied, a conveyance belt 302 that conveys a document fed from the document tray 300 by the sheet feeding device 301 by sandwiching it with a document placing table 206, and a light source 207. And optical system 20
There is one that is roughly configured by a discharge tray 303 on which a document whose image is read by a document reading unit configured by 8 and the like is stacked.

[0052]

As described above, in the sheet feeding device of the present invention, the sheets stacked on the sheet stacking means are held by the side regulating means, and the air is jetted toward one side of the sheet by the separating means. However, it is possible to prevent the air blown from the separating means from entering below the lowest sheet by adsorbing the vicinity of one side of the lowest sheet of the sheets to the sheet stacking means side by the end suction means. , The lowest sheet and other sheets can be separated regardless of the type of sheet (size, basis weight, thickness), and the separated lowest sheet can be reliably fed by the feeding means. Can be effectively prevented from being double-fed. Further, according to the present invention, since the separating means injects the intake air toward one side portion of the seat, it is not necessary to provide a member for restricting the rear end position of the seat, and the device is downsized and complicated. Can be effectively prevented, and even if the tip of the sheet is deformed such as curl,
The lowermost sheet and the other sheets can be reliably separated, and the double feeding of the sheets can be effectively prevented. Further, in the sheet feeding apparatus of the present invention, the separating unit can inject air toward one side portion of the sheet to reliably separate the lowermost sheet adsorbed by the feeding unit from other sheets. Therefore, it is not necessary to increase and change the wind pressure and the air volume of the separating unit according to the sheet stacking amount, and it is possible to prevent the generation of noise due to the increase in the capacity of the separating unit and improve the quietness of the apparatus.

Further, in the sheet feeding device of the present invention, the frictional resistance acting between the end suction means and the sheet is made smaller than the frictional resistance acting between the feeding means and the sheet. The sheet can be reliably fed by the feeding means without applying a resistance that causes a feeding failure to the sheet.

Further, in the sheet feeding apparatus of the present invention, the surface of the end suction means contacting the sheet is substantially flush with the surface of the feeding means contacting the sheet, and the suction surface of the feeding means is the same. Since the friction coefficient is smaller than the coefficient of friction of the sheet, the sheet can be smoothly and reliably fed without exerting a resistance that causes a sheet feeding failure.

Further, in the sheet feeding apparatus of the present invention, the end suction means always sucks the sheet regardless of whether the sheet suction of the feeding means is on or off. It is possible to reliably feed only the lowermost sheet and prevent double feeding of the sheets more effectively without the air blown from the separating means entering below.

Further, since the image forming apparatus of the present invention is equipped with the sheet feeding apparatus as described above, the image can be surely formed on the sheet and the reliability of the image forming apparatus is remarkably improved. The image forming apparatus can be downsized, and the quietness can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sheet feeding device according to a first embodiment of the present invention.

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

FIG. 3 is a front view (front view) of the sheet feeding device.

FIG. 4 is a plan view (top view) of the sheet feeding device.

FIG. 5 is a plan view of a sheet feeding device according to a second embodiment of the present invention.

6 is a view as seen from the direction of arrow A in which a part of the sheet feeding device of FIG. 5 is cut away.

FIG. 7 is an operation explanatory view of the sheet feeding device. 7A is a first operation explanatory diagram, FIG. 7B is a second operation explanatory diagram, and FIG. 7C is a third operation explanatory diagram.

FIG. 8 is a sectional view of an image forming apparatus including a sheet feeding device according to the present invention.

FIG. 9 is a side sectional view of a conventional sheet feeding device.

FIG. 10 is a plan view (top view) of a main part of a conventional sheet feeding device.

FIG. 11 is a perspective view of a tray in a conventional sheet feeding device.

FIG. 12 is an explanatory view of air flow distribution in the conventional sheet feeding apparatus.

[Explanation of symbols]

 100 Sheet Tray (Sheet Stacking Means) 101 Feeding Means 105 Nozzle (Separating Means) 110 Sheet Feeding Device 120 Side Regulation Member (Side Regulation Means) 121 Side Regulation Member (Side Regulation Means) 130 End Suction Member (End Suction) Means) 202 image forming unit (image forming means) S sheet S1 lowermost sheet

Claims (6)

[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 orthogonal to a sheet feeding direction, and a stacking unit for stacking the sheet on the sheet stacking unit. Feeding means for vacuum-adsorbing and transporting the lowermost sheet of the sheets, and injecting air to one side portion of the sheet on the sheet stacking means, the sheet vacuum-adsorbed by the feeding means to another side. A sheet feeding device comprising: a separating unit that separates the sheet from the sheet; and an end suction unit that sucks the vicinity of one side of the lowermost sheet of the sheets to the sheet stacking unit side. 2. The sheet according to claim 1, wherein the frictional resistance acting between the end suction means and the sheet is made smaller than the frictional resistance acting between the feeding means and the sheet. Feeding device. 3. The suction surface of the end suction means that comes into contact with the sheet is substantially on the same plane as the suction surface of the feeding means that comes into contact with the sheet, and has a friction coefficient greater than that of the suction surface of the feeding means. The sheet feeding device according to claim 1, wherein the sheet feeding device is formed so as to have a small friction coefficient. 4. The sheet feeding apparatus according to claim 1, wherein the sheet attracting force of the edge attracting means is smaller than the sheet attracting force of the feeding means. 5. The sheet feeding apparatus according to claim 1, wherein the edge suction means always sucks the sheet regardless of whether the sheet suction of the feeding means is on or off. 6. The method according to claim 1, wherein
An image forming apparatus, comprising: the sheet feeding device according to the item 1; and an image forming unit that forms an image on a sheet fed from the sheet feeding device.