JP2020073416A - Paper feeding device, and image forming apparatus - Google Patents

Abstract

To provide a paper feeding device and an image forming apparatus for reducing a problem that causes a feeding failure because the uppermost paper is hooked by a regulation member without double-feeding paper when the uppermost paper floated by air blown by an air blowing device is conveyed by a conveyor belt in a feeding direction while being sucked by a suction device.SOLUTION: A first vertical facing surface part 80a (a vertical facing surface part) is formed from a position of a reference surface part 73 in a feeding direction to a position separated to a feeding direction downstream side on an upper end side of a facing surface part on the facing surface part of a regulation plate 80 (a regulation member) for regulating movement of paper P2 under the uppermost paper P1 floated by an air blowing device 79 in the feeding direction, and an inclination facing surface part 80b is formed so as to be almost the same position by gradually approaching a position of a reference surface part 73 in the feeding direction downward from the bottom edge of the first vertical facing surface part 80a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet feeding device that feeds a sheet such as a transfer sheet, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine or a printing machine of them.

  BACKGROUND ART Conventionally, in an image forming apparatus such as a copying machine, a printer, or a printing machine, as a paper feeding device that feeds paper such as transfer paper, it has been aimed at the uppermost paper of a plurality of papers placed on a tray. There is known an air suction method in which air is blown from a blowing device, and the uppermost sheet floated by the blown air is sucked by a suction device and is conveyed in a feeding direction by a conveying belt (for example, , Patent Documents 1 and 2.).

Specifically, the sheet feeding device in Patent Document 1 and the like is provided with a mounting portion (bottom plate), a regulating member (sheet blocking member), a blowing device, a suction device, a conveyor belt (suction belt), and the like. ..
Then, among the plurality of sheets stacked on the stacking unit, while the air is blown to the end surface of the uppermost sheet by the air blower, the uppermost sheet that has floated is sucked by the suction device, and the uppermost sheet is Adsorbed on the conveyor belt. Then, the sheet adsorbed on the conveyor belt is fed in the feeding direction by the traveling of the conveyor belt.
Here, above the inner wall surface (reference surface portion) on the downstream side of the paper feeding tray in the feeding direction, a substantially plate-shaped paper blocking member (regulating member) that stands upright in the vertical direction is installed. There is. The sheet blocking member restricts the operation in the feeding direction with respect to the sheet below the uppermost sheet floated by the blower.

  On the other hand, in Patent Document 2, an air blower (opening) of an air blower that blows air toward the uppermost paper among a plurality of papers stacked on a mounting portion is inclined with respect to the vertical direction. In addition to the above, there is disclosed a technique in which the shutter plate that opens and closes the air blowing portion is also formed to be inclined.

The above-described conventional sheet feeding device is a blower device when the sheet placed on the placing portion is in a back curl state (a state in which the sheet is convexly curved upward in the feeding direction). When the uppermost sheet of paper floated by the air blown from the suction device is sucked by the suction device and is conveyed in the feeding direction by the conveyor belt, the sheet is caught by the regulation member (sheet blocking member) and jams. There was a possibility that feeding failure such as (paper jam) might occur.
On the other hand, it is conceivable to apply the technique of Patent Document 2 to form the regulating member (sheet blocking member) so as to be inclined with respect to the vertical direction. However, in that case, the sheet below the uppermost sheet to be regulated by the regulating member may be fed (double-fed) by the transport belt together with the uppermost sheet.

  The present invention has been made to solve the above-described problems, and conveys the uppermost sheet floated by the air blown from the air blower in the feeding direction by the feed belt in a state of being sucked by the suction device. It is another object of the present invention to provide a sheet feeding device and an image forming apparatus in which the uppermost sheet is prevented from being double-fed and the trouble that the feeding failure occurs due to the uppermost sheet being caught.

  The sheet feeding device according to the present invention is a sheet feeding device that feeds sheets in a predetermined feeding direction, and a state in which a plurality of sheets are in contact with a reference surface portion that rises upward on the downstream side in the feeding direction. The stacking unit formed so that it can be stacked and the downstream side in the feeding direction with respect to the above-mentioned placing unit, the air is directed toward the uppermost sheet of the plurality of sheets stacked on the above-mentioned placing unit. An air blower for blowing the sheet to raise the sheet, and a feeding direction with respect to the sheet below the uppermost sheet floated by the blower, installed so as to stand up from the reference surface portion. Member that regulates the operation of the above, a suction device that is installed above the placement unit and that sucks the uppermost sheet that is floated by the air blower, and the uppermost member that is suctioned by the suction device. When the paper of A transport belt for transporting the paper in the feeding direction, the regulation member includes a facing surface portion facing the paper floated by the blower, and the facing surface portion has a feeding direction at an upper end side thereof. The vertical facing surface portion formed so as to stand in a substantially vertical direction such that the position of the reference surface portion is separated from the position of the reference surface portion in the feeding direction downstream side, and the lower end of the vertical facing surface portion. From the downward direction, the position in the feeding direction gradually rises toward the position in the feeding direction of the reference surface portion so as to be substantially the same position, and is formed so as to be inclined and erected with respect to the vertical direction. And an inclined facing surface portion.

  According to the present invention, when the uppermost sheet floated by the air blown from the air blower is sucked by the suction device and is conveyed by the conveying belt in the feeding direction, the sheet is not double-fed. It is possible to provide a sheet feeding device and an image forming apparatus in which the problem that the upper sheet is caught by the regulation member and the feeding failure occurs is reduced.

1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows a paper feeder. FIG. 3 is a perspective view showing the inside of the paper feeding device with the transport device removed. FIG. 3 is an enlarged view showing a main part of the paper feeding device. It is a perspective view which expands and shows the vicinity of a regulation member. It is a figure which shows operation | movement of a paper feeder. It is an enlarged view showing the principal part of the conventional paper feeder. FIG. 9 is a diagram showing a main part of a paper feeding device as a first modification. FIG. 9 is an enlarged perspective view of the vicinity of the regulation member in the paper feeding device of FIG. 8. It is a figure which shows the principal part of a paper feed device as a modified example 2.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the duplicate description thereof will be appropriately simplified or omitted.

First, the overall configuration and operation of the image forming apparatus 1 will be described with reference to FIG.
In FIG. 1, 1 is a copying machine as an image forming apparatus, 2 is a document reading unit that optically reads image information of a document D, and 3 is a photoconductor that is an exposure light L based on the image information read by the document reading unit 2. An exposure unit for irradiating the drum 5 with 4 an image forming unit for forming a toner image (image) on the photosensitive drum 5, and a transfer unit 7 for transferring the toner image formed on the photosensitive drum 5 onto a sheet P (sheet). A transfer unit (image forming unit) 10, an original document conveyance unit (automatic original document conveyance device) for conveying the set original document D to the original document reading unit 2, and reference numerals 12 and 13 for feeding paper sheets P such as transfer sheets. A cassette (paper feeding device) 17, a registration roller (timing roller) that conveys the paper P toward the transfer unit 7, 20 a fixing device that fixes the toner image (unfixed image) carried on the paper P, 21 Is a fixing roller installed in the fixing device 20, and 22 is a fixing roller. A pressure roller installed in the fixing device 20, 31 is a discharge tray on which the paper P discharged from the apparatus main body 1 is stacked, and 70 is a paper feeding device (large-capacity paper feeding) in which a large amount of paper P is stored. Device).

With reference to FIG. 1, the operation of the image forming apparatus 1 during normal image formation will be described.
First, the document D is transported (fed) from the document table in the direction of the arrow by the transport rollers of the document transport unit 10 and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads the image information of the document D passing above.
Then, the optical image information read by the document reading unit 2 is converted into an electric signal and then transmitted to the exposure unit 3 (writing unit). Then, the exposure unit 3 emits exposure light L such as laser light based on the image information of the electric signal toward the photoconductor drum 5 of the image forming unit 4.

On the other hand, in the image forming unit 4, the photoconductor drum 5 is rotated in the clockwise direction in the drawing, and image information is formed on the photoconductor drum 5 through a predetermined image forming process (charging process, exposing process, developing process). An image (toner image) corresponding to is formed.
After that, the image formed on the photoconductor drum 5 is transferred onto the sheet P conveyed by the registration rollers 17 in the transfer unit 7 as an image forming unit.

On the other hand, the sheet P conveyed to the transfer section 7 (image forming section) operates as follows.
First, one of the plurality of paper feed cassettes 12 and 13 of the image forming apparatus main body 1 is automatically or manually selected (for example, the uppermost paper feed cassette 12 is selected). ). Then, the uppermost one sheet of the paper P stored in the paper feed cassette 12 is fed by the paper feed mechanism 52 (which is composed of a feed roller, a pickup roller, a backup roller, and the like), and the conveyance path. Is transported to. After that, the sheet P passes through the transport path in which the plurality of transport rollers are arranged and reaches the position of the registration roller 17.
When the large-capacity sheet feeding device 70 (large-capacity sheet feeding device) installed on the side of the apparatus main body 1 is selected, the mounting portion 72 of the sheet feeding device 70 (see FIG. 2 can be referred to). ), The uppermost sheet P among the plurality of sheets P stacked in (1) is fed toward the conveyance path in which the conveyance roller 55 is installed by the conveyance belt 76a of the conveyance device 76, and then the registration roller 17 You will reach the position.

The sheet P that has reached the position of the registration roller 17 is conveyed toward the transfer unit 7 (image forming unit) at the same timing as the image formed on the photosensitive drum 5 in order to align the image.
Then, the paper P after the transfer process reaches the fixing device 20 via the transport path after passing through the position of the transfer unit 7. The sheet P reaching the fixing device 20 is sent between the fixing roller 21 and the pressure roller 22, and the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. (Fixing process). The sheet P after the fixing process, in which the toner image is fixed, is sent out from between the fixing roller 21 and the pressure roller 22 (which is a fixing nip), and then discharged from the image forming apparatus main body 1 to output an output image. As a result, the sheets are stacked on the discharge tray 31.
Thus, a series of image forming process is completed.

Next, the sheet feeding device 70 (large-capacity sheet feeding device), which is characteristic of the present embodiment, will be described in detail with reference to FIGS.
With reference to FIGS. 2 to 4, the paper feeding device 70 is for feeding the paper P in a predetermined feeding direction (the direction of the arrow in FIG. 2), and includes a paper storage unit 71, The transport device 76 and the air blower 79 are included.
The sheet storage unit 71 includes a mounting unit 72 (elevation tray), a reference surface unit 73 (reference fence), an end fence 74, a side fence 75, a regulation plate 80 as a regulation member, a height detection sensor 82, and the like. There is.
The transport device 76 includes a transport belt 76a stretched and supported by two roller members, a suction device 78 (belt suction device), and the like. Then, the paper P stored in the paper storage / accommodation section 71 is conveyed by the conveyance device 76 in the feeding direction indicated by the arrow in FIGS. 2 and 4.

Specifically, the reference surface portion 73 is an inner wall portion of a reference fence that is formed so as to stand upright in the upward direction on the downstream side of the sheet storage portion 71 (placement portion 72) in the feeding direction.
The mounting portion 72 is formed so that it can be stacked with the plurality of sheets P in contact with the reference surface portion 73. Further, in the mounting portion 72, the position of the uppermost sheet P1 in the height direction is a predetermined position (the position shown in FIG. 4 and is detected by the height detection sensor 82 regardless of the number of stacked sheets P). It is configured to be able to move up and down. That is, the loading section 72 is for loading a plurality of sheets P, and the lifting mechanism moves up and down in the direction of the double-headed arrow in FIG. 2 according to the number of loaded sheets (remaining amount). A known mechanism can be used as a lifting mechanism for lifting the mounting portion 72.

  At the installation position of the height detection sensor 82 (the position in the height direction, which is the position separated from the conveyor belt 76a shown in FIG. 4 by the distance H), the uppermost sheet P1 is conveyed by the conveyor belt 76a. In order to carry out suction conveyance, it is determined based on the floatability of the blower 79 and the suction of the suction device 78. In the present embodiment, the height detection sensor 82 is a reflective photosensor, and the paper P (inside the paper storage portion 71) is passed through the light transmission portion (window portion) formed in the reference surface portion 73 (reference fence). Paper P.).

2 and 3, etc., the end fence 74 has a position in the feeding direction (with respect to the reference surface portion 73) according to the size of the sheet P in the feeding direction (the left and right direction in FIG. 2). The interval) is manually (or automatically) variable.
With reference to FIG. 3, the side fences 75 have an interval in the width direction according to the size of the paper P in the width direction (the direction orthogonal to the feeding direction and perpendicular to the paper surface of FIG. 2). Can be changed manually (or automatically).
The user moves the side fence 75 and the end fence 74 so as to hit the placed paper P after placing the grasped paper P (sheet bundle) on the placement portion 72 so as to abut against the reference surface portion 73. By the operation, the setting of the sheet P (sheet bundle) in the sheet storage unit 71 is completed.
In the paper storage unit 71, a regulation plate 80 as a regulation member is installed above the reference plane 73 (reference fence), which will be described in detail later.

As shown in FIGS. 2 and 4, the blower device 79 is installed on the downstream side (the left side in FIGS. 2 and 4) in the feeding direction with respect to the placement unit 72 (sheet storage unit 71). There is. The air blower 79 blows air toward the uppermost sheet P1 of the plurality of sheets P stacked on the mounting portion 72 to float the sheet P1 (see FIG. 6B). Can be referenced).
More specifically, the blower device 79 includes a blower fan, a blower duct, a first blower nozzle 79a, a second blower nozzle 79b, and a shutter that opens and closes the two blower nozzles 79a and 79b separately. Then, the air taken in from the blower fan is ejected from the first blower nozzle 79a through the blower duct, and the air is blown to the uppermost sheet P (and the sheet P overlapping therebelow), so that the air is blown. The uppermost sheet P is separated by the positive pressure of and is floated upward. Then, since suction is performed by the suction device 78 at the upper side, the suction of the uppermost sheet P toward the transport belt 76a is promoted. The blower 79 (first blower nozzle 79a) ejects air toward the uppermost sheet P at the same timing as when the suction operation by the suction device 78 is started, or more than that. It is preferable that the timing is a little earlier.

Here, in the paper feeding device 70 in the present embodiment, the paper feeding device 70 is installed on the downstream side in the feeding direction with respect to the mounting portion 72 (paper storage portion 71) and floated by the air blowing device 79 (first air blowing nozzle 79a). A second blower is provided to blow air between the uppermost sheet P1 and the lower sheet P2 to separate the lower sheet P2.
In the present embodiment, the blower device 79 including the first blower nozzle 79a is configured to function also as the above-described second blower device. Specifically, the blower 79 is provided with a first shutter that opens and closes the first blow nozzle 79a and a second shutter that opens and closes the second blow nozzle 79b. When the opening and closing operations of these shutters are controlled to open the first blower nozzle 79a and close the second blower nozzle 79b, the blower device 79 causes the uppermost sheet to move as shown in FIG. 6B. When the first blower nozzle 79a is closed and the second blower nozzle 79b is opened by functioning as a blower (first blower) that blows air toward P1 to float the paper P1, FIG. As shown in, the air blower 79 functions as a second air blower that blows air toward the uppermost sheet P1 and the sheet P2 below it to separate the lower sheet P2.
In this embodiment, the blower device (first blower device) and the second blower device are integrally configured as one blower device 79, but the blower device (first blower device) and the second blower device are combined. Can also be provided separately.

With reference to FIG. 2, FIG. 4, etc., the suction device 78 is installed above the mounting portion 72 (sheet storage portion 71). The suction device 78 is for sucking the uppermost sheet P1 floated by the air blower 79 (air blown from the first air blow nozzle 79a). In other words, the suction device 78 is configured to generate a negative pressure of air above the plurality of sheets P stacked on the mounting portion 72 and suck the uppermost sheet P1.
Specifically, the suction device 78 includes a suction fan, a suction duct, a suction chamber, and the like. The suction chamber is installed inside the conveyor belt 76a, and the opening formed at the bottom thereof is formed so as to communicate with the space below through a plurality of small-diameter holes formed in the conveyor belt 76a. A hole formed on one end side in the width direction is connected to a suction fan via a suction duct. Then, by operating the suction fan, air is sucked from the bottom of the conveyor belt 76a in the direction of the white arrow in FIG.

With reference to FIGS. 2 and 4, the conveyor belt 76a conveys the uppermost sheet P1 in the feeding direction in a state where the uppermost sheet P1 is attracted by suction by the suction device 78.
More specifically, the conveyor belt 76 a is installed above the paper storage unit 71, on the most downstream side in the feeding direction, and across the discharge port of the paper feeding device 70. The conveyor belt 76a is stretched and supported by two roller members, and one roller member is rotationally driven by the drive motor to rotate (run) in the clockwise direction in FIG. A plurality of small-diameter holes are formed on the entire surface of the conveyor belt 76a.

  Here, referring to FIGS. 2 to 6, in sheet feeding device 70 in the present embodiment, a regulating plate 80 as a regulating member is installed so as to stand up from reference surface portion 73 upward. .. The regulation plate 80 functions as a regulation member that regulates the operation in the feeding direction with respect to the sheet P2 below the uppermost sheet P1 floated by the blower 79 (air blown from the first blowing nozzle 79a). To do. That is, in the regulation plate 80 (regulation member), the lower sheet P2 which is not scheduled to be suctioned and transported by the transport belt 76a is fed together with the uppermost sheet P1 which is scheduled to be suctioned and transported by the transport belt 76a. This is to prevent the trouble of (double feed). Specifically, when the lower sheet P2 is about to be double-fed, the sheet P2 interferes with the regulation plate 80 and the operation in the feeding direction (feeding) is restricted.

Here, with reference to FIG. 4, FIG. 5, etc., the regulation plate 80 (regulation member) is a facing surface portion (a surface portion facing the side of the paper storage portion 71) facing the paper P floated by the blower 79. .) Has been formed.
The facing surface portion of the regulation plate 80 includes a first vertical facing surface portion 80a as a vertical facing surface portion, an inclined facing surface portion 80b, and a second vertical facing surface portion 80c.

The position of the first vertical facing surface portion 80a (vertical facing surface portion) in the feeding direction is separated from the position of the reference surface portion 73 in the feeding direction to the downstream side in the feeding direction on the upper end side of the regulation plate 80 (facing surface portion). It is formed so as to stand in a substantially vertical direction so as to be positioned. That is, the first vertical facing surface portion 80a is formed at a position shifted to the left in FIG. 4 by the distance M with respect to the reference surface portion 73.
The above-mentioned distance M is the top end of the sheet P1 when the uppermost sheet P1 floated by the air blower 79 and having a back curl is adsorbed and conveyed by the conveyor belt 76a (suction device 78). It is set according to the locus (behavior) of the tip (the tip in the feeding direction) so as not to interfere. The distance M is the minimum necessary and the shorter the distance M is, the more compact the regulation plate 80 (paper feeding device 70) can be.

The inclined facing surface portion 80b is vertically arranged so that the position in the feeding direction gradually approaches the position of the reference surface portion 73 in the feeding direction from the lower end of the first vertical facing surface portion 80a to the substantially same position. It is formed so as to be inclined with respect to the direction. That is, the inclined facing surface portion 80b has its upper end shifted to the left side of FIG. 4 by the distance M with respect to the reference surface portion 73, its lower end in the vicinity of the upper end of the reference surface portion 73, and from the upper end to the lower end. Inclining to the right of FIG.
Note that the “inclination” here includes not only a linear inclination but also a curved inclination (a curved shape). That is, the inclined facing surface portion 80b is defined to include all of them if the distance M from the reference surface portion 73 continuously increases upward. The inclination angle of the inclined facing surface portion 80b (the counterclockwise angle with the reference surface portion 73 in FIG. 4) is set to an acute angle (in the present embodiment, about 30 to 60 degrees). ing.

  The second vertical facing surface portion 80c rises in a substantially vertical direction from the lower end of the inclined facing surface portion 80b downward so that the position in the feeding direction is substantially the same as the position in the feeding direction of the reference surface portion 73. Is formed. That is, the second vertical facing surface portion 80c is formed along the reference surface portion 73 (reference fence). More specifically, although the illustration is simplified in FIG. 4, as shown in FIG. 5, the second vertical facing surface portion 80c is formed to be substantially flush with the reference surface portion 73.

By using the regulation plate 80 (regulation member) configured as described above, the sheet P placed on the placing section 72 is in a back curled state as shown in FIG. 6A (feeding upward). Even when the uppermost sheet P1 floated by the air blown from the air blower 79 (first air blow nozzle 79a) is sucked by the suction device 78 and is conveyed. When the sheet P1 is conveyed by the belt 76a in the feeding direction, the problem that the sheet P1 is caught by the regulation plate 80 and a feeding failure such as a jam (paper jam) occurs is surely reduced.
That is, as shown in FIG. 7, when the regulating plate 800 formed along the reference surface portion 73 from the upper end to the lower end is used, the back curled sheet P1 is sucked and conveyed by the conveying belt 76a. At that time, the leading end of the sheet is caught by the regulation plate 800, which causes a feeding failure such as a jam.
On the other hand, in the present embodiment, the upper end side (first vertical facing surface portion 80a) of the regulation plate 80 is shifted to the downstream side in the feeding direction, and toward that portion (first vertical facing surface portion 80a). Since the inclined facing surface portion 80b that is gently inclined from the reference surface portion 73 is provided, even if the paper P1 is curled back, it is floated by the air blower 79 and sucked and conveyed by the conveying belt 76a (suction device 78). In the series of operations, the leading end of the sheet P1 (the leading end in the feeding direction) is less likely to interfere with the regulation plate 80. Therefore, the problem that the sheet P1 is caught by the regulation plate 80 and a feeding failure such as a jam (paper jam) occurs is reliably reduced.
Further, since the facing surface portion of the regulation plate 80 is not formed only by the inclined facing surface portion from the lower end to the upper end, but the first vertical facing surface portion 80a is formed on the upper end portion side, the uppermost sheet is formed. It is possible to reliably reduce the problem that the sheet P2 below the sheet P1 is fed (double-fed) by the conveyor belt 76a. That is, when the uppermost sheet P1 is sucked and conveyed by the conveyor belt 76a, the lower sheet P2 is caught by the first vertical facing surface portion 80a, and its feeding (double feeding) is restricted. ..

In addition, in the present embodiment, the lower end of the inclined facing surface portion 80b (or the upper end of the second vertical facing surface portion 80c) is a distance from the conveyor belt 76a, which is detected by the predetermined position (detected by the height detection sensor 82). It is set at a position in the height direction substantially the same as the position in the height direction separated by H.).
As a result, the function of the regulation plate 80 described above is easily exerted.

Further, in the present embodiment, the regulation plate 80 (regulation member) is configured so that its position in the height direction can be manually adjusted.
Specifically, with reference to FIG. 5, the regulation plate 80 is fixed to the reference surface portion 73 (reference fence) by fastening screws 85 and 86, and the position in the height direction thereof is determined. Then, by loosening the fastening of the screws 85 and 86, the regulation plate 80 is configured to be movable in the vertical direction with respect to the reference surface portion 73 (reference fence). Specifically,
Holes through which the screws 85 and 86 pass are elongated holes extending in the vertical direction in the reference plane 73 (reference fence). A scale 73a is formed on the reference surface portion 73 so that the adjustment position of the regulation plate 80 in the height direction can be grasped.
By configuring the position of the regulation plate 80 in the height direction to be finely adjusted as described above, the uppermost sheet P and the lower sheet P2 are floated due to various factors such as dimensional accuracy and assembly accuracy of various components. Even in the case where the series of behaviors during suction / conveyance slightly changes, it is possible to arrange the regulation plate 80 applied to the change. Further, depending on the type, thickness, size, etc. of the sheet P placed on the placing section, a series of behaviors of the uppermost sheet P and the lower sheet P2 at the time of floating, sucking, and conveying may be slightly changed. Even in such a case, it is possible to arrange the regulation plate 80 applied to the change.

Hereinafter, the operation of the sheet feeding device 70 in the present embodiment will be described as a summary with reference to FIGS.
Here, as shown in FIG. 6A, it is assumed that the back-curled sheets P1 and P2 are set in the placing section 72 (sheet storing section 71).
When the user presses the copy button of the image forming apparatus 1, first, as shown in FIG. 6B, air is blown from the first blowing nozzle 79a of the blowing device 79 toward the uppermost sheet P1, The uppermost sheet P1 floats toward the transport device 76. At about the same time, suction by the suction device 78 is started, and the uppermost sheet P1 is sucked onto the transport belt 76a as shown in FIG. 6C. At this time, the inclined facing surface portion 80b is formed on the regulation plate 80 so that the leading end portion thereof does not interfere with the regulation plate 80 even when the floating sheet P1 is back-curled. In the state of FIG. 6B, the lower sheet P2 also slightly floats.
Thereafter, as shown in FIG. 6C, air is blown from the second blowing nozzle 79b of the blowing device 79 toward the uppermost sheet P1 and the lower sheet P2, and the uppermost sheet P1 is blown. The lower sheet P2 is separated from P1, and the separated lower sheet P2 drops toward the placing portion 72.
Then, as shown in FIG. 6D, the conveyance belt 76 a starts rotating (running) in the direction of the arrow, and the sheet P <b> 1 in a state of being adsorbed by the conveyance belt 76 a is fed toward the conveyance roller 55. Will be sent. At this time, even if the sheet P1 to be fed is in a back curl state, the leading end of the sheet P1 hanging downward does not interfere with the regulation plate 80 and the lower sheet P2 is prevented from being double-fed. Since the upper end portion (first vertical facing surface portion 80a) of 80 is formed, a paper feed failure such as a jam or a double feed does not occur.
After that, the uppermost sheet P1 is conveyed in the direction of the arrow, and its rear end passes through the position of the suction device 78, and then the next sheet P2 (which is newly the uppermost sheet). Then, the operations of FIGS. 6B to 6D are repeated.

<Modification 1>
FIG. 8 is a diagram illustrating a main part of the sheet feeding device 70 according to the modified example 1, and is a diagram corresponding to FIG. 6C in the present embodiment. Further, FIG. 9 is an enlarged perspective view showing the vicinity of the regulating member in the paper feeding device 70, and is a view corresponding to FIG. 5 in the present embodiment.
As shown in FIGS. 8 and 9, in the first modification, the second suction device 90 (separation suction device) is installed on the downstream side in the feeding direction with respect to the placement unit 72 (sheet storage unit 71). There is. The second suction device 90 is for sucking the sheet P2 below the uppermost sheet P1 floated by the blower 79 (air blown from the first blowing nozzle 79a), and is described above. This is for sucking the lower sheet P2 and further positively separating it in the process of FIG. 6C.
The second suction device 90 includes a duct 91 having a suction port 91a, a suction fan connected to the duct 91, and the like. When the second suction device 90 is installed in this way, the duct 91 restricts the operation in the feeding direction with respect to the sheet P2 below the uppermost sheet P1 floated by the blower 79. Can function as. Then, the edge portion 91b of the suction port 91a in the duct 91 can function as the facing surface portion of the regulating member. Specifically, the duct is formed by forming a first vertical facing surface portion, an inclined facing surface portion, or a second vertical facing surface portion on the edge portion 91b of the suction port 91a, similarly to the facing surface portion of the regulation plate 80 in the present embodiment. 91 can be made to function similarly to the regulation plate 80 in the present embodiment.

<Modification 2>
FIG. 10 is a diagram showing a main part of a sheet feeding device 70 as a modified example 2, and is a diagram corresponding to FIG. 6A in the present embodiment.
As shown in FIG. 10, the second modification is configured so that the movement mechanism 101 can automatically move the regulation plate 80 in the vertical direction. That is, the regulation plate 80 (regulation member) is configured so that its position in the height direction can be automatically adjusted. As the moving mechanism 101, for example, a moving mechanism configured by a pinion rack mechanism can be used.
With this configuration, the position of the regulation plate 80 in the height direction is automatically adjusted based on at least one of the type, thickness, and size of the sheet P placed on the placing section 72. You can also Specifically, referring to FIG. 10, the type of the paper P is detected based on the information about the paper P input on the operation panel 102 installed on the exterior portion of the apparatus body 1, or a known thickness detection sensor is used. The thickness of the paper P is detected by 103, the size of the paper P is detected by a known size detection sensor 104, and the appropriate height of the regulation plate 80 is controlled by the control unit 100 based on the detection results. Is required. Then, the movement mechanism 101 is controlled by the control of the control unit 100 so that the regulation plate 80 has an appropriate height.
When configured in this way, the regulation plate 80 can properly function regardless of the type, thickness, size, etc. of the paper P, as in the present embodiment.

As described above, the sheet feeding device 70 according to the present embodiment regulates the operation in the feeding direction with respect to the sheet P2 below the uppermost sheet P1 floated by the blower 79 (regulating plate). The first vertical facing surface portion 80a (vertical facing surface portion) is formed on the facing surface portion of the (member) on the upper end side thereof at a position distant from the position of the reference surface portion 73 in the feeding direction to the downstream side in the feeding direction. The inclined facing surface portion 80b is formed so as to gradually approach the position of the reference surface portion 73 in the feeding direction downward from the lower end of the facing surface portion 80a and be located at substantially the same position.
As a result, when the uppermost sheet P1 floated by the air blown from the blower 79 is sucked by the suction device 78 and is conveyed in the feeding direction by the conveyor belt 76a, the sheets P1 and P2 are double-fed. Without this, it is possible to reduce the problem that the uppermost sheet P1 is caught by the regulation plate 80 and a feeding failure occurs.

Although the present invention is applied to the sheet feeding device 70 installed in the monochrome image forming apparatus 1 in the present embodiment, it goes without saying that the present invention is also applied to the sheet feeding device installed in the color image forming apparatus. The present invention can be applied.
Further, in the present embodiment, the present invention is applied to the paper feeding device 70 installed in the electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and other methods are also applicable. The present invention can also be applied to a sheet feeding device installed in an image forming apparatus (for example, an inkjet image forming apparatus, a stencil printing machine, or the like).
Further, in the present embodiment, the present invention is applied to the large-capacity sheet feeding device 70 in the image forming apparatus 1, but the sheet feeding cassettes 12 and 13 as the sheet feeding devices are of the air suction type. Therefore, the present invention can be naturally applied, and naturally, the present invention can be applied to the original conveying unit 10 (automatic original conveying apparatus) as a paper feeding apparatus as long as it is of the air suction type. You can
Even in such cases, the same effect as that of the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be appropriately modified, other than what is suggested in the present embodiment, within the scope of the technical idea of the present invention. is there. Further, the number, position, shape, etc. of the constituent members are not limited to those in the present embodiment, and the number, position, shape, etc. suitable for carrying out the present invention can be adopted.

  In the present application, “paper” includes not only transfer sheets but also sheet-shaped recording media such as OHP, and further includes originals fed by an automatic document feeder as a paper feeding device. It is defined as.

1 image forming apparatus (image forming apparatus main body),
70 Paper feeder (large capacity paper feeder),
71 paper storage,
72 Placement part (elevation tray),
73 Reference surface part (reference fence),
73a scale,
74 end fence, 75 side fence,
76 transport device,
76a conveyor belt,
78 suction device (belt suction device),
79 blower,
79a 1st ventilation nozzle (blower),
79b second blowing nozzle (second blowing device),
80 restriction plate (regulation member),
80a First vertical facing surface portion (vertical facing surface portion),
80b inclined facing surface portion,
80c second vertical facing surface portion,
82 Height detection sensor,
85, 86 screws,
90 Second suction device (separation suction device),
91 duct (regulating member),
91a Suction port, 91b Edge portion (opposing surface portion),
P, P1, P2 paper.

JP, 2015-110464, A Japanese Patent No. 4894573

The sheet feeding device according to the present invention is a sheet feeding device that feeds sheets in a predetermined feeding direction, and includes a reference surface portion that is erected upward on the downstream side in the feeding direction , and is capable of stacking sheets. The placement unit, a blower unit that is installed on the downstream side in the feeding direction with respect to the placement unit, blows air toward the sheets stacked on the placement unit to float the sheet, and the reference surface unit. From the above, the restricting unit is installed so as to stand up from above, and restricts the operation of the sheet floated by the air blowing unit in the feeding direction, and the air blowing unit is installed above the placing unit. comprising a suction device for sucking is floated sheets, and a conveyor belt for conveying paper sucked by the suction device in the feeding direction by the regulating unit, Oite at its upper end side, of the reference surface Separated from the position in the feeding direction to the downstream side in the feeding direction As will become location is obtained by including a vertical surface portion formed to stand up in a substantially vertical direction, and a slope portion which is formed to be closer to the reference surface from the lower end of the vertical surface portion.

Claims (8)

A paper feeding device for feeding paper in a predetermined feeding direction,
A placing portion formed to be stackable in a state where a plurality of sheets are in contact with a reference surface portion that is erected upward on the downstream side in the feeding direction,
An air blower that is installed on the downstream side in the feeding direction with respect to the placement unit, and blows air toward the uppermost sheet of the plurality of sheets stacked on the placement unit to levitate the sheet,
A restricting member that is installed so as to stand upright from the reference surface portion and that restricts the operation in the feeding direction with respect to a sheet below the uppermost sheet that is levitated by the blower,
A suction device that is installed above the placement unit and that sucks the uppermost sheet floated by the blower,
A transport belt that transports the sheet in the feeding direction in a state where the uppermost sheet is sucked by suction by the suction device,
Equipped with
The restriction member includes a facing surface portion that faces the sheet floated by the blower,
The facing surface portion,
On its upper end side, a vertical facing surface portion formed so as to stand in a substantially vertical direction such that the position in the feeding direction is a position separated from the position in the feeding direction of the reference surface portion to the downstream side in the feeding direction. When,
From the lower end of the vertical facing surface portion downward, the position in the feeding direction gradually approaches the position in the feeding direction of the reference surface portion, and stands up inclined with respect to the vertical direction so that the position becomes substantially the same position. An inclined facing surface portion formed to
A sheet feeding device comprising:   The facing surface portion of the restricting member extends in a substantially vertical direction from the lower end of the inclined facing surface portion downward so that the position in the feeding direction is substantially the same as the position in the feeding direction of the reference surface portion. The sheet feeding device according to claim 1, further comprising a second vertical facing surface portion formed so as to stand upright. The placement unit is configured to be movable up and down so that the position of the uppermost sheet in the height direction becomes a predetermined position regardless of the number of sheets to be stacked,
The sheet feeding device according to claim 1 or 2, wherein a lower end of the inclined facing surface portion is at a position in the same height direction as the predetermined position.   The sheet feeding device according to any one of claims 1 to 3, wherein the regulating member is configured such that its position in the height direction can be adjusted manually or automatically.   The position in the height direction of the regulating member is automatically adjusted based on at least one of the type, thickness, and size of the sheet placed on the placing section. Paper feeder. A second suction device that is installed on the downstream side in the feeding direction with respect to the placement unit and that suctions a sheet below the uppermost sheet floated by the blower,
The second suction device includes a duct having a suction port.
The restriction member is the duct,
The sheet feeding device according to claim 1, wherein the facing surface portion of the regulation member is an edge portion of the suction port in the duct.   The sheet is installed on the downstream side in the feeding direction with respect to the placing section, and air is blown between the uppermost sheet floated by the air blower and the sheet below the upper sheet to separate the lower sheet. The sheet feeding device according to any one of claims 1 to 6, further comprising a second air blower.   An image forming apparatus comprising the sheet feeding device according to claim 1.

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