JP2004131291A - Sheet feeding device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely feed paper by air even if the paper is sheets easily causing sucking phenomenon such as art paper and coat paper under high humidity. <P>SOLUTION: A shutter 415 vertically movable and having a slit 416 is fitted between the side end of a sheet bundle S and a blow duct 408 for sorting the sheet bundle by spraying air to the side end. The velocity of the blown air is varied by the movement of the shutter 415, and the sheet bundle is surely sorted by an increase in air velocity caused by the passing of the air through the slit 416. When the air velocity is below a specified value, a suction belt 407 is rotated to surely convey the uppermost sheet. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a sheet feeding apparatus that separates and feeds sheets one by one from a sheet bundle stacked in a sheet storage unit.

Conventionally, in image forming apparatuses such as copiers and printers, cut sheets as recording media that can be fed continuously are usually limited to high-quality paper and plain paper specified by the copier manufacturer. Such a sheet has low surface smoothness and low air permeability, so that air can easily flow between the sheets. Therefore, when removing sheets one by one from the stacked sheets, the sheets are attracted to each other and the weight is reduced. There was little occurrence of transmission.

However, in recent years, along with the diversification of recording media, in addition to cardboard, OHP paper, tracing paper, etc., art paper and coated paper that have been coated on the surface of the sheet to provide whiteness and gloss to meet the market demand for colorization There is an increasing demand for image formation even on a sheet having a smooth surface such as paper. However, these OHP papers, tracing papers, art papers, coated papers, and the like have high smoothness and air permeability. Therefore, especially when sheets are stacked in a highly humid environment, the sheets are attracted to each other, and the conventional copier In the friction separation method generally used in printers and printers, there is a problem that double feed and misfeed frequently occur.

On the other hand, the air-feeding type, which separates and feeds one sheet at a time from the upper sheet by a suction device and a conveyor belt arranged at the same time by blowing air from the side edge of the sheet bundle, is used for printing. It is used in the industry and some copiers. Compared to the friction separation method, this air feeding method has (1) wider latitude for setting the feeding conditions for materials, (2) can support high-speed feeding, (3) high durability, and (4) low running cost It has such advantages.

Many proposals related to such air feeding have been made.For example, air is blown to the leading end side of a sheet stacked on a sheet feeding table by an air blowing device from a direction parallel to the upper surface of the sheet, and at the same time, In addition, a method has been proposed in which an intake cylinder opened above a seat is set to a negative pressure by a negative pressure generating device and sucked. According to this sheet feeding device, the uppermost one of the sheets stacked on the sheet feeding table is lifted by the suction action from the opening, and the air blowing device is applied to the gap formed between the uppermost sheet and the next sheet. It is intended to reliably separate the two sheets by blowing air from the surface (for example, see Patent Document 1).

JP-A-62-249835

However, as described above, OHP paper, tracing paper, art paper, coated paper, and the like have high smoothness and air permeability, and therefore, when sheets are stacked in a highly humid environment, adsorption between the sheets occurs. . Here, when the air feeding method is adopted, since the air blown from the side ends of the sheet bundle is a constant flow, the upper part of the sheet bundle floats in a bundle state at the interface where the suction force is relatively weak. However, air cannot flow into the gaps between the sheet bundles that have floated, and it has been very difficult to reliably separate the sheet bundles one by one.

The present invention has been made in view of the above situation, material handling, high-speed paper feeding, in the air paper feeding system that is superior in terms of high durability, etc., in a simple configuration, reliably release the adsorption of the sheets, An object of the present invention is to provide a sheet feeding apparatus that prevents occurrence of misfeed and double feeding, to reduce the size of the apparatus, reduce product costs and running costs, and improve reliability.

The present invention provides a sheet stacking means for stacking a plurality of sheets, a sheet sucking and conveying means for sucking and conveying by suction of air one by one from the top sheet stacked on the sheet stacking means, Air blowing means for blowing air to the side end of the sheet bundle loaded on the stacking means, and wind speed variable means for changing the wind speed of the air blown from the air blowing means, the top sheet by the wind speed variable means When the wind speed of the air blown in the vicinity of the bundle is equal to or less than a predetermined value, the sheet suction operation of the sheet suction and conveyance unit is performed.

The present invention provides a sheet stacking means for stacking a plurality of sheets, a sheet sucking and conveying means for sucking and conveying by suction of air one by one from the top sheet stacked on the sheet stacking means, Air blowing means for blowing air to the side end of the sheet bundle loaded on the stacking means, and wind direction variable means for changing the wind direction of the air blown from the air blowing means, the top sheet by the wind direction variable means When the air blown to the vicinity of the bundle is equal to or less than a predetermined value, the sheet transport operation of the sheet suction transport unit is performed.

The present invention provides a sheet stacking means for stacking a plurality of sheets, a sheet sucking and conveying means for sucking and conveying by suction of air one by one from the top sheet stacked on the sheet stacking means, Air blowing means for blowing air to the side end of the sheet bundle stacked on the stacking means, wind speed varying means for changing the wind speed of the air blown from the air blowing means, and a wind direction of the air blown from the air blowing means And a wind direction variable means for changing the wind speed, and when the wind speed of the air blown out near the uppermost sheet bundle by the cooperative action of the wind speed variable means and the wind direction variable means is equal to or less than a predetermined value, the sheet suction conveyance means Is carried out.

As described above, according to the present invention, the wind speed of the air blown in the vicinity of the uppermost sheet bundle by the wind speed variable unit that changes the wind speed of the air blown to the side end of the sheet bundle stacked on the sheet stacking unit is a predetermined value. Since the sheet conveyance operation of the sheet suction conveyance unit is performed at the following times, it is possible to provide an air feeding type sheet feeding apparatus capable of reliably separating and conveying only the top sheet by the sheet suction conveyance unit. I do.

The following is a description of a first embodiment of the present invention, with reference to the accompanying drawings.

(overall structure)
FIG. 1 is a cross-sectional view illustrating a configuration of a main part of an embodiment of a copying machine 1 showing an example of an image forming apparatus of the present invention.

As shown in FIG. 1, the copying machine 1 includes an image reader 200 for reading an image of a document, a printer 300 for forming an image on a sheet, and a paper feeding unit 400 for supplying the sheet to the printer 300. The paper feeding unit 400 includes paper decks 401 and 451 having a common paper feeding mechanism. The paper deck 401 can store up to 1000 sheets, and the paper deck 451 can store up to 1500 sheets. The paper feeding unit 400 will be described later in detail.

The image reader 200 is equipped with an automatic document feeder 100 for automatically feeding a document to the image reader 200. The automatic document feeder 100 feeds the documents set upward on the document tray 101 one by one from the top page one by one to the left in the figure, and flows the document on the platen glass 102 from the left through a curved path. The sheet is conveyed to the right through the reading position, and then discharged toward the external discharge tray 112.

(4) When the original passes through the scanning reading position on the platen glass 102 from left to right, the original image is read by the scanner unit 104 held at a position corresponding to the scanning reading position. This reading method is a method generally referred to as original reading. Specifically, when a document passes through the scanning reading position, the reading surface of the document is illuminated with the light of the lamp 103 of the scanner unit 104, and the reflected light from the document is passed through the mirrors 105, 106, and 107 to the lens. It is led to 108. The light passing through the lens 108 forms an image on the imaging surface of the image sensor 109.

By transporting the document so as to pass from the flow reading position from left to right in this way, the document reading scan in which the direction perpendicular to the document transport direction is the main scanning direction and the transport direction is the sub-scanning direction is performed. Done. That is, when the original passes through the scanning reading position, the original image is conveyed in the sub-scanning direction while the original image is read by the image sensor 109 line by line in the main scanning direction, so that the entire original image is read. The image that has been read is converted into image data by the image sensor 109 and output. The image data output from the image sensor 109 is input to the exposure control unit 110 of the printer 300 as a video signal after being subjected to predetermined processing in an image signal control unit (not shown).

It is also possible to convey the original on the platen glass 102 by the automatic original feeder 100, stop the original at a predetermined position, and scan the scanner unit 104 from left to right in this state to read the original. This reading method is a so-called fixed original reading method.

When reading a document without using the automatic document feeder 100, first, the user lifts the automatic document feeder 100, places the document on the platen glass 102, and scans the scanner unit 104 from left to right. Then, the original is read. That is, when reading a document without using the automatic document feeder 100, fixed document reading is performed.

The exposure controller 110 of the printer 300 modulates and outputs a laser beam based on the input video signal, and the laser beam is irradiated on the photosensitive drum 111 while being scanned by a polygon mirror. An electrostatic latent image corresponding to the scanned laser beam is formed on the photosensitive drum 111. Here, the exposure control unit 110 outputs a laser beam so that a correct image (an image that is not a mirror image) is formed at the time of original fixed reading, as described later.

(4) The electrostatic latent image on the photosensitive drum 111 is visualized as a developer image by a developer supplied from a developing device (not shown). The sheet fed from each of the paper decks 401 and 451 is conveyed between the photosensitive drum 111 and the transfer unit 116 at a timing synchronized with the start of laser beam irradiation by the registration roller 115. The developer image formed on the photosensitive drum 111 is transferred onto the sheet fed by the transfer unit 116.

(4) The sheet on which the developer image has been transferred is conveyed to the fixing unit 117, and the fixing unit 117 fixes the developer image on the sheet by applying heat and pressure to the sheet. The sheet that has passed through the fixing unit 117 is discharged to a first discharge tray 119 via a first discharge roller 118 or a second discharge tray 121 via a second discharge roller 120 by switching a flapper (not shown).

Next, the paper deck of the air feeding type according to the present invention will be described in detail. The paper deck 401 and the paper deck 451 differ only in the maximum number of sheets that can be stored. Therefore, the same or corresponding components are denoted by the same reference numerals and will be described based on the paper deck 401.

FIG. 2 is a perspective view of the paper deck 401 of the air feeding type according to the present embodiment. The paper deck 401 is configured to stack and store a sheet bundle S on an intermediate plate 403 which is a sheet stacking means provided to be movable up and down in a storage 402. Rails 404 and 405 (rails 404 are shown in FIG. 1) are provided at the lower edges on both sides of the storage box 402, and the front side (the operation unit side of the copying machine, which is perpendicular to the paper surface in FIG. 1) with respect to the apparatus main body 1A. ) Can be withdrawn. The sheet bundle S stacked and stored in the storage 402 is fixed at a predetermined position by the pre-separation plate 406 at the leading end, by the trailing end regulating plate 412 at the rear end, and by side regulating plates 410 and 411 at the side end. It is placed.

A sheet feeding unit 409 is provided above the stacked sheet bundle S in the sheet feeding direction, which is a sheet suction conveyance unit for sucking and sending out the uppermost sheet by air. The sheet feeding section 409 includes a suction duct 408 connected to suction means (not shown) and capable of generating a static suction pressure above the sheet bundle, and a suction belt having a number of holes surrounding the suction duct 408. Reference numeral 407 is provided so as to be rotatable in the sheet feeding direction.

{Circle around (4)} In the sheet feeding unit 409, the sheet is sucked by the suction belt 407 by the suction duct 408, and the sheet is fed by rotating the suction belt 407.

Next, the configuration and operation of the air blowing means for blowing the blowing air provided in the side regulating plate 410 to the side end of the sheet bundle S will be described in detail with reference to FIG.

FIG. 3 is a cross-sectional view when FIG. 2 is viewed from the paper feeding direction. Here, a blowing means is provided inside the side regulating plate 410. The blowing means is connected to a blowing fan 417 (shown in FIG. 2) which is a supply source of blowing air, and is connected to the blowing fan 417. A blowing duct 413 having an opening 414 opened toward the side end of the sheet bundle S stacked and stored in the storage 402 is provided. Thereby, the blowing air is blown from the opening 414 toward the side end of the sheet bundle S, and the sheets are separated.

(4) A shutter 415, which is a wind speed variable means, is provided which is movable in a substantially vertical direction between a side end of the sheet bundle S and the opening 414 by a drive source (not shown) (for example, a motor or a solenoid). Part of the shutter 415 has a slit 416 having a width sufficiently smaller than the width of the opening 414. The shutter 415 does not block the air blown out of the opening 414 when it is at the lowest position, and completely blocks the air blown out of the opening 414 when it is at the highest position. At a position between the lowermost position and the uppermost position of the shutter 415, the air blown out from the opening 414 is blown to the side end of the sheet bundle S through the slit 416 of the shutter 415. Note that a detection unit Sa that can detect the position of the shutter 415 when the shutter 415 is at the highest position is provided.

Next, the operation will be described in detail. When a sheet bundle to be fed is set on the paper deck 401 and inserted into the apparatus main body 1A, the intermediate plate 403 is lifted up to a predetermined height by a not-shown sheet height detecting means by a not-shown lift-up motor. Here, when the copy button is pressed, the paper feeding operation is started.

First, the upper suction means starts the suction operation, the suction duct 408 starts the suction operation, and the blowing fan 417 operates to blow air to the side end of the sheet bundle S. Here, the shutter 415 is driven by a driving source (not shown) and reciprocates up and down between the side end of the sheet bundle S and the opening 414 of the blowing duct 413.

In the initial state, the shutter 415 is at the lowest position, and the air blown from the entire opening 414 is blown to the side edge of the sheet bundle S (FIG. 3A). Next, the shutter 415 moves upward, and the slit 416 moves with it. Here, when the slit 416 faces the opening 414, the air velocity passing through the slit 416 increases due to the difference in width. Since the air whose wind speed has been increased by passing through the slit 416 continuously blows upward and blows to the side end of the sheet bundle S, a better loosening effect than the conventional steady flow air can be expected (FIG. 3B). ), FIG. 3 (c)).

Further, when the shutter 415 reaches the uppermost position, the opening 414 of the blowing duct 413 is completely closed by the shutter 415, so that all the sheet bundles floated by the blowing air fall, and only the uppermost sheet is sucked. The suction of the duct 408 causes the suction belt 407 to be sucked (FIG. 3D). At this point, the uppermost sheet is sent out by driving and rotating the suction belt 407. By repeating this, the sheets can be reliably separated and fed one by one.

In the case where it is desired to feed a sheet, such as art paper or coated paper, which tends to be attracted by high humidity, the shutter 415 may be moved up and down several times as a pre-feed operation. For example, as described above, in the one-way loosening operation from the lowermost position to the uppermost position of the shutter 415 (FIG. 3A → FIG. 3D), if the sheet cannot be separated due to the suction of the sheet, reciprocation is performed a plurality of times (FIG. (D) → FIG. 3 (a) → FIG. 3 (d) a plurality of times), so that air can reliably flow between the sheets of the sheet bundle that has been sucked, and the suction can be released. Then, the sheet bundle loosened at the position shown in FIG. 3D is blown when the sheet is fed, so that only the uppermost sheet adsorbed on the adsorption belt 407 is conveyed, thereby reliably preventing the second and subsequent sheets from being double-fed. can do.

In the above description, the initial position of the shutter 415 is set at the lowest position, but the position is not limited to this and may be any position. The air supply source of the suction means and the blowing means may be a fan such as a sirocco fan or a compressor.

FIG. 4 shows the relationship between the drive timing of the suction belt 407 and the movement cycle of the shutter 415. If the suction belt 407 is driven when the shutter 415 is at the highest position, a good separation and feeding operation can be performed. Therefore, as is apparent, by setting the moving period of the shutter 415 to n times (n = 1, 2, 3,... (Integer)) the driving timing of the suction belt 407, a favorable sheet can be obtained without reducing productivity. It becomes possible to provide a feeding device. As an example, when the number of copies of the apparatus main body is 50 cpm (copy-per-minute), the moving speed is 50 rpm (revolution-per-minute) in the shutter moving period (a) shown in FIG. It becomes 100 rpm. The moving speed of the shutter may be set to an optimum value according to the conditions such as the material. For example, in the case of a sheet in which the adsorption phenomenon is likely to occur between the sheets, separation can be reliably performed by increasing the moving cycle of the shutter 415.

The air passing through the slit 416 when the slit 416 faces the opening 414 as shown in FIGS. 3B and 3C has a maximum wind speed. As a result of an experiment, the maximum wind speed depends on the type of sheet. Although there is some variation, about 20 m / sec is optimal. Further, in the above embodiment, as shown in FIG. 3D, when the shutter 415 completely covers the opening 414, the suction belt 407 is rotated to separate and feed the sheet, but the sheet is not completely shut off. If the sheet does not float even in this state, the sheet may be separated and fed by rotating the suction belt 407 while blowing air. As a result of the experiment, if the paper is plain paper, there is no problem if it is about 30% (6 m / sec) or less of the maximum wind speed, and if it is thick paper such as coated paper, there is no problem if it is 40% (8 m / sec) or less. And separate feeding is possible.
(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals in the drawings denote the same components as in the first embodiment, and a description thereof will be omitted.

In the present embodiment, the blowing duct 413 and the vertically movable shutter 415 are provided on the leading end side of the sheet bundle in the sheet feeding direction. Further, a separation nozzle 419 is provided in a separation duct 418 connected to a separation fan (not shown), and the separation nozzle 419 supplies the separation air obliquely toward the suction belt 407. This separation air works effectively to attract only the top sheet to the suction belt and separate and drop the next sheet and below.

In the case of the present embodiment, the shutter 415 reciprocates from the uppermost position (FIG. 5A) to the lowermost position (FIG. 5B), but the suction belt 407 and the blowing duct 413 in the sheet feeding direction. A paper path P for transporting the sheet separated between the paper paths to the downstream is provided, and the paper path P cannot be closed. Therefore, the uppermost position for closing the opening 414 as in the first embodiment. The shutter 415 cannot be moved upward.

Therefore, a valve 420 as a wind speed variable means is provided inside the blowing duct 413, and the inside of the blowing duct 413 can be shielded / opened freely, and a state in which the blowing air is blown from the opening 414 (FIG. 5A 5) and a shut-off state (the state of the valve 420 in FIG. 5B). Thus, in the present embodiment, it is not shown that the top sheet is attracted to the attraction belt 407 by the attraction operation after the sheet bundle is sufficiently separated by the blowing air from the opening 414 by the reciprocating operation of the shutter 415 a predetermined number of times. After being detected by a detecting means such as a suction sensor, the blowing air is shut off by blocking the valve 420 (the state shown in FIG. 5B), and only the uppermost paper is cooperated with the separation air from the separation nozzle 419. And the next sheet can be completely separated.

In the present embodiment, setting the moving speed of the shutter 415 as described in the second embodiment can prevent the productivity from being affected. That is, the movement cycle of the shutter 415 can be freely set according to the material and environmental conditions. Therefore, it is possible to provide a sheet feeding apparatus that can achieve both productivity and separation performance.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals in the drawings denote the same components as in the first embodiment and the second embodiment, and a description thereof will be omitted.

In the present embodiment, as shown in FIGS. 6 and 7, when the suction belt 407 is driven (when it is turned on), the wind speed of the blowing air is set to be smaller than the wind speed when loosening between the paper sheets. I do. In this embodiment, as shown in FIG. 6, a shutter 415 having a slit 416 is reciprocated up and down in a duct opening 414 so that the sheet is sufficiently loosened when the slit 416 is above the sheet bundle, that is, when the blowing air velocity is high. At this time, the suction belt 407 is not driven (FIG. 6A). Next, when the slit 416 moves downward, that is, when the blowing air velocity is low, the suction belt 407 is driven to feed the paper downstream (FIG. 6B). As a result of the experiment, as shown in FIG. 7, the wind speed as the separating air between the sheets slightly varies depending on the type of the sheet, but is optimally about 20 m / sec. Also, the wind speed of the blowing air at the time of feeding the paper, that is, at the time of driving the suction belt 407 (when it is on), is not completely zero, but is such that the sheet floats and a plurality of sheets are not pressed against the suction belt 407 (wind speed). (Vm / sec or less), the sheet may be separated and fed by rotating the suction belt 407 while blowing air to some extent. As a result of an experiment, there is no problem if the value is about 30% (6 m / sec) or less of the maximum wind speed for plain paper, and 40% (8 m / sec) or less for thick paper such as coated paper. If there is no problem, separation and feeding are possible.
Further, in the above example, since the valve 420 is not provided as compared with the second embodiment, an inexpensive apparatus can be provided. Further, the cycle of the intensity of the blowing air can be set to n times (n = 1, 2, 3,... (Integer)) the drive timing of the suction belt 407 as in the first embodiment. In this case, it is possible to provide a sheet feeding device that achieves both productivity and separation performance.

Further, the method of reducing the blowing velocity of the blowing air at the time of sheet feeding is not limited to the method described above, and may be performed by the strength of the blowing air driving source. Alternatively, the maximum shielding area of the valve 420 in the second embodiment may be reduced by the blowing duct 413. It can also be implemented by setting the cross-sectional area to 30 to 40%.

(Embodiment 4)
A fourth embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals in the drawings denote the same components as in the first and second embodiments, and a description thereof will be omitted.

In the present embodiment, a swing nozzle 421 that is a wind direction variable means capable of vertically rotating the upper end of the sheet bundle in the blowing duct 413 provided at the leading end side of the sheet bundle is provided. The swing nozzle 421 continuously blows upward air in FIG. 8A, substantially horizontal direction in FIG. 8B, and downward air in FIG. Since the swing nozzle 421 blows air while rotating up and down, air with a continuously changing wind direction can be given to the sheet bundle, and the adsorbed sheets and the stacked sheets are slightly shifted up and down. The effect of allowing air to flow into the gaps between the sheets and separating them is very high.

Further, by setting the drive timing of the suction belt 407 to the timing shown in FIG. 8B or FIG. 8C, it is possible to avoid blowing up the lowermost sheet with extra air, so that good sheet feeding is achieved. Separation performance can be secured.

It is to be noted that the configuration of the present embodiment is combined with the configuration of turning on / off the air blowing of the second or third embodiment and the configuration of reducing the wind speed at the sheet feeding timing, so as to be more optimal. Separation performance may be ensured.

As described above, in each embodiment, the sheet bundle can be reliably separated, and air can flow between the sheets even if the sheets are absorbed by coated paper or the like in a high humidity environment. Thus, separation can be reliably performed.

も ち ろ ん Of the embodiments described above, it is of course possible to use the embodiments in appropriate combinations. In each of the above embodiments, the positions of the blowing duct 413 and the shutter 415 are arbitrary as long as they correspond to the side end or the front end of the sheet bundle S.

Further, the configuration of the separation nozzle 419 for blowing out the separation air described in the second embodiment, or a combination with another type of separation means such as a separation claw, a separation pad, and a reverse roller (retard roller) is also optional. is there.

Sectional view of a copying machine illustrating an embodiment of the present invention. FIG. 1 is a perspective view of a paper deck illustrating an embodiment of the present invention. Configuration diagram illustrating a first embodiment of the present invention. Explanatory drawing of timing in the device of the first embodiment Configuration diagram illustrating a second embodiment of the present invention. Configuration diagram illustrating a third embodiment of the present invention. Explanatory drawing of timing in the third embodiment Configuration diagram illustrating a fourth embodiment of the present invention.

Explanation of reference numerals

300 Printer 401, 451 Paper deck 407 Suction belt 408 Suction duct 413 Blowing duct 414 Opening 415 Shutter 416 Slit 421 Swing nozzle

Claims (11)

Sheet stacking means for supporting a plurality of sheets,
Sheet suction and conveyance means for sucking and conveying by suction of air one by one from a top sheet supported by the sheet stacking means;
Air blowing means for blowing air to a side end of the sheet bundle supported by the sheet stacking means,
Wind speed variable means for changing the wind speed of the air blown from the air blowing means,
With
The sheet feeding device according to claim 1, wherein when the wind speed of the air blown to the vicinity of the uppermost sheet bundle by the wind speed changing unit is equal to or less than a predetermined value, the sheet conveying operation of the sheet suction conveying unit is performed. 2. The sheet feeding device according to claim 1, wherein the wind speed changing unit periodically changes the wind speed, and the cycle of the wind speed change is set to an integral multiple of a period of a sheet conveying operation of the sheet suction conveying unit. . The wind speed variable unit is a shutter that moves in a substantially vertical direction between the air blowing unit and a side end of the sheet bundle, and the shutter has a slit through which air can pass, and the position of the slit is The sheet feeding device according to claim 1, wherein the air velocity is changed by increasing or decreasing the supply air. 2. The sheet feeding device according to claim 1, wherein the wind speed changing unit changes a wind speed by increasing or decreasing supply air from an air supply source of the air blowing unit. 3. 2. The sheet feeding apparatus according to claim 1, wherein the wind speed varying means includes an air shielding means capable of shielding / opening a flow path of air from the air blowing means. 2. The sheet feeding apparatus according to claim 1, wherein the sheet conveying operation of the sheet suction and conveying unit is performed when a wind speed of air blown near the uppermost sheet bundle by the wind speed changing unit is substantially stopped. Sheet loading means for loading a plurality of sheets,
Sheet adsorbing and conveying means for adsorbing and conveying by suction of air one sheet at a time from the top sheet stacked on the sheet stacking means;
Air blowing means for blowing air to a side end of the sheet bundle stacked on the sheet stacking means,
Wind direction variable means for changing the direction of the air blown from the air blowing means,
With
The sheet feeding device according to claim 1, wherein when the air blown to the vicinity of the uppermost sheet bundle by the wind direction changing unit is equal to or less than a predetermined value, the sheet conveying operation of the sheet suction conveying unit is performed. 8. The sheet feeding apparatus according to claim 7, wherein the wind direction changing means periodically changes a wind direction, and the wind direction change cycle is set to an integral multiple of a sheet conveyance operation cycle by the sheet suction conveyance means. The sheet feeding device according to claim 7, wherein the wind direction changing unit includes a swing nozzle rotatable in a vertical direction. Sheet loading means for loading a plurality of sheets,
Sheet adsorbing and conveying means for adsorbing and conveying by suction of air one sheet at a time from the top sheet stacked on the sheet stacking means;
Air blowing means for blowing air to a side end of the sheet bundle stacked on the sheet stacking means,
Wind speed variable means for changing the wind speed of the air blown from the air blowing means,
Wind direction variable means for changing the direction of the air blown from the air blowing means,
With
When the wind speed of the air blown to the vicinity of the uppermost sheet bundle by the cooperative action of the wind speed varying means and the wind direction varying means is equal to or less than a predetermined value, the sheet conveyance operation of the sheet suction conveyance means is performed. Sheet feeding device. A sheet feeding device according to any one of claims 1 to 10,
An image forming unit for forming an image on a sheet fed from the sheet feeding device.

Images