JP4760328B2 - Paper feeding device and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these.

An electrophotographic image forming apparatus typified by a copying machine or a laser printer has a paper feeding device having a paper separating mechanism for feeding recording media (sheets) for recording images one by one from a paper feeding tray accommodated one by one. Is provided.
As this sheet separating mechanism, various configurations have been conventionally proposed (for example, see Patent Document 1). Japanese Patent Application Laid-Open No. 2004-228561 discloses a configuration in which the air flow is controlled so that the upper side of the upper surface of the paper has a negative pressure, and the paper is separated and fed by the upward lift of the paper generated by the negative pressure.

  Examples of the configuration of the paper separating mechanism disclosed in Patent Document 1 include the following. That is, the paper separation mechanism is configured to blow air from the direction perpendicular to the side surface of the paper to the side surface and top surface of the paper loaded in the paper feed tray, and between the air spraying means and the paper side surface. Air blocking means that is arranged in parallel with the side surface and moves in the direction perpendicular to the sheet surface by the driving force of the electric motor. For this reason, when the drive motor is driven, the air flow path moves from the upper side to the lower side with respect to the side surface of the sheet. Further, by reciprocating this vertical movement, the effect of releasing the adhesion can be increased.

  Patent Document 1 also discloses a configuration of a sheet separating mechanism that includes direction changing means instead of air blocking means. The direction varying means includes a plurality of rectifying plates provided in parallel in the vertical direction at a predetermined interval between the air blowing means and the paper, and an angle varying unit that varies the support angle of the rectifying plates by the driving force of the electric motor. Have. And when a drive motor drives, an angle variable part will drive and a baffle plate will incline. For this reason, it is possible to release the adhesion between the sheets by sequentially blowing air from the upper sheet. Further, since air is blown while rectifying air by the rectifying plate, the air flow path can be moved without generating vortices, and the pressure loss of air can be reduced.

  Patent Document 1 also discloses a configuration of a sheet separating mechanism including a sheet lifting / lowering unit that lifts and lowers stacked sheets instead of the air blocking unit and the direction changing unit. The sheet lifting / lowering means has a bottom plate provided on the bottom surface of the paper feed tray, an arm that is in sliding contact with the lower surface of the bottom plate, and an electric motor that rotates the arm. When the electric motor is driven, the arm rotates and pushes up the end of the bottom plate, whereby the paper loaded on the bottom plate moves up and down. For this reason, by swinging the bottom plate, the sheet moves in the vertical direction with respect to the flow path of the stopped air blowing means. That is, the flow path of the air blowing means is moved relative to the paper, and air is blown from the top to the bottom with respect to the side surface of the paper.

JP-A-11-5543

However, in the configuration using the air blocking means and the configuration using the direction changing means, it is necessary to arrange a complicated mechanism near the edge of the stacked paper. Therefore, a space for arranging the mechanism is required, leading to an increase in the size of the apparatus. That is, it is difficult to reduce the size of the apparatus, and it is also difficult to reduce the cost because of its complicated mechanism.
Further, in the configuration using the paper lifting / lowering means, although a relatively simple structure can be obtained, the paper is moved by the paper lifting / lowering means for aligning the stacked paper with respect to the paper feeding means. It is necessary to wait for the paper feed height. That is, the sheet feeding operation and the sheet separating operation by air cannot be operated independently. For this reason, when dealing with high productivity, the paper lifting means is operated at a high speed, which requires a large driving force and durability of the driving mechanism, leading to an increase in size and cost of the apparatus. .

  The present invention has been made to solve the technical problems as described above, and an object of the present invention is to easily realize downsizing and cost reduction with a simple configuration.

For this purpose, a sheet feeding device to which the present invention is applied has a stacking unit for stacking sheets, and a blowing port that opens to face a side surface of a stack of sheets stacked on the stacking unit. A paper separating unit that blows air toward the side of the sheet bundle and floats the sheet, and a sending unit that sequentially sends out the upper sheet separated by the sheet separating unit among the sheet bundle loaded on the stacking unit, Is included.
The paper separation unit is loaded on the stacking unit and a control unit that controls the air volume from the blowout port so that the floating position of the paper blown and floated from the blowout port moves up and down the upper end of the blowout port. One end, which is rotatably held in the main body of the device so that it can be displaced in the stacking direction of the paper being placed, is located above the upper end of the outlet and contacts the stopper provided in the main body of the device to limit the rotation range. The other end portion is installed such that the initial position is between the upper end and the lower end of the outlet on the stacking portion, and a regulating portion that regulates the floating height of the paper that is blown and floated from the outlet The direction of the paper loaded on the stacking portion is provided between the one end portion and the other end portion of the restricting portion, and the other end portion of the restricting portion is located between the upper end and the lower end of the outlet. The regulating part is urged with elasticity And the sheet is lifted against the pressing force of the restricting part as the air volume blown from the outlet increases, and the pressing force received from the restricting part increases as the sheet rises. Paper that is regulated at a position that balances the lift force by the balance, and that is regulated at the balanced position, descends while receiving a pressing force from the regulating part as the air volume blown from the blowout port decreases. It is.

From another point of view, an image forming apparatus to which the present invention is applied has a stacking unit that stacks sheets, and a blowing port that opens to face a side surface of a bundle of sheets stacked on the stacking unit. The paper separation part that blows air by blowing air toward the side of the paper bundle from the mouth, the supply source that supplies air to the paper separation part, and the paper separation part of the paper bundle loaded on the stacking part The image forming apparatus includes a sending unit that sequentially feeds the separated upper-level sheets one by one, and an image forming unit that forms an image on the sheet sent by the sending unit.
The paper separation unit is loaded on the stacking unit and a control unit that controls the air volume from the blowout port so that the floating position of the paper that is floated by the air of the supply source from the blowout port moves up and down the upper end of the blowout port. One end portion that is rotatably held by the apparatus main body so as to be displaceable in the paper stacking direction is positioned above the upper end of the outlet, and comes into contact with a stopper provided in the apparatus main body so that the rotation range is The other end that is restricted is installed so that the initial position is between the upper and lower ends of the air outlet on the stacking unit, and the floating height of the paper that floats by blowing the air of the supply source from the air outlet is regulated A regulating part that is mounted between the one end and the other end of the regulating part, and the other end of the regulating part is positioned between the upper end and the lower end of the outlet. The restricting part is elastic in the direction of the paper The pressing force received from the regulating portion according to possess and urging portion, the paper along with the paper against the pressing force of the regulation portion in accordance with the wind amount of air blown out from the air outlet is increased to flotation increases for biasing The paper is regulated at a position that balances with the lift due to air, and the paper that is regulated at the balanced position descends while receiving a pressing force from the regulating portion as the air volume blown from the blowout port decreases. It is what.
In addition, the image forming apparatus further includes a supply source control unit that changes an air supply amount of the supply source according to information on sheets loaded in the stacking unit.

  According to the present invention, it is possible to easily configure the sheet separating mechanism, and it is possible to easily realize downsizing and cost reduction.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to the present embodiment. In the figure, the inside of the apparatus is viewed from the front side (front side, out side).
The image forming apparatus shown in FIG. 1 includes an image forming apparatus main body 10 that forms an image on a sheet using an electrophotographic method. The image forming apparatus main body 10 includes a control unit 11 that controls the entire apparatus with respect to paper conveyance and image formation. The control unit 11 is connected to a document reading device 12A that reads a document and outputs image data, and an external device 12B such as a PC that generates image data and outputs the image data to the outside. When image data is output to the control unit 11 from the document reading device 12A or the external device 12B, a toner image is formed by the image forming unit 13 using the image data, and the toner image is transferred to a sheet (sheet). It is fixed later and a print image is output.

  The image forming unit 13 is formed by being exposed by a photosensitive drum 14 for carrying a toner image, an image writing device (hereinafter referred to as ROS) 15 for exposing the charged photosensitive drum 14, and the ROS 15. And a developing device 16 for developing the electrostatic latent image on the photosensitive drum 14. The image forming unit 13 also includes a transfer roller 17 that transfers the toner image developed by the developing device 16 and carried on the photosensitive drum 14 to a sheet, and a fixing that fixes the toner image transferred by the transfer roller 17 to the sheet. And a cleaner 19 that removes and collects the toner remaining on the photosensitive drum 14.

The image forming apparatus main body 10 is also provided with a series of paper transport systems. On the lower side of the image forming apparatus main body 10, paper feed trays (stacking units) 21, 22, 23, and 24 on which a stack of sheets are stacked are provided. Decorated. Each of the paper feed trays 21 to 24 is provided with a nudger roller (pickup roller, delivery roller) 25, a feed roller (paper feed roller) 26, and a retard roller 27. Each of the nudger roller 25, the feed roller 26, and the retard roller 27 constitutes a part of the delivery unit. Each of the paper feed trays 21 to 24 is provided with a paper separating device to be described later. The nudger roller 25 is configured to move up and down at a predetermined timing.
A series of paper transport systems is configured in this way, and the paper handling device handles the paper, and the paper taken out one by one from the paper feed trays 21 to 24 by the nudger roller 25, the paper feed roller 26, and the retard roller 27 is transported. Sending out towards the road 31.

In the sheet conveyance path 31, a conveyance roller 32 provided in the vicinity of the paper feed roller 26, gates 33 and 34 for switching the sheet conveyance direction in the vicinity of the discharge unit of the image forming apparatus main body 10, and gates 33 and 34. A conveyance roller 35 provided therebetween is provided. Further, in the sheet conveyance path 31, a discharge roller 38 that discharges to the discharge trays 36 and 37 in a face-down state (with the recording surface down), and a face-up tray 39 in a face-up state (with the recording surface up). And a face-up roller 40 for discharging.
In addition, when performing double-sided recording on a sheet, a sheet reversing conveyance path 41 is provided for reversing and feeding the sheet recorded on one side to a transfer unit (contact portion between the photosensitive drum 14 and the transfer roller 17). It has been.
In addition, on the side surface of the image forming apparatus main body 10, an openable and closable manual feed tray 42 is provided for supplying sheets of sizes and types that are not accommodated in the four-stage sheet feeding trays 21 to 24.

  An image forming process of the image forming apparatus main body 10 configured as described above will be described. The surface of the photosensitive drum 14 of the image forming unit 13 is charged by a charger (not shown) and then exposed by the ROS 15 based on input image data to form an electrostatic latent image. On the other hand, in the developing device 16, toner is supplied from a toner box (not shown) and stirred inside the developing device 16. The electrostatic latent image formed on the photosensitive drum 14 is developed through, for example, a developing roller of the developing device 16, and a toner image is formed on the photosensitive drum 14. The toner image formed on the photoconductive drum 14 is transferred to a sheet by a transfer unit in which the transfer roller 17 is in contact with the photoconductive drum 14, heated and fixed by a fixing device 18, and output. On the other hand, residual toner remaining on the photosensitive drum 14 after the transfer is peeled off from the photosensitive drum 14 by the cleaner 19 and collected.

[First Embodiment]
FIG. 2 is a schematic configuration diagram showing the paper feed tray 21 according to the first embodiment together with the paper separating device 51, and is a plan view seen from the arrow A in FIG. Hereinafter, although the paper feed tray 21 will be described, the other paper feed trays 22 to 24 have the same configuration as that of the paper feed tray 21 and will not be described.
As shown in FIG. 2, the paper feed tray 21 includes side guides 21 a and 21 b and an end guide 21 c for placing paper at a fixed position in plan view. In the case of the first embodiment, the side guide 21a is fixed, and the side guide 21a and the end guide 21c are configured to be movable according to the size of the paper. A sheet separating device 51 that separates sheets one by one is disposed on the side guide 21a side.
The paper feed tray 21 has a bottom plate 21d on which paper is placed. The bottom plate 21d is adjusted by a push-up arm (not shown) so that the upper or uppermost sheet is positioned at a predetermined sheet feeding position. That is, every time a sheet is fed, the bottom plate 21d is raised by the action of a push-up arm (not shown).

  Since the paper feed tray 21 is configured in this way, the paper in the paper feed tray 21 is fed as follows. That is, the sheets separated one by one in the sheet feeding tray 21 by the action of the sheet separating device 51 are fed in the direction of arrow F by the nudger roller 25 and then fed one by one by the feed roller 26 and the retard roller 27. It is sent to the downstream side.

FIG. 3 is a schematic configuration diagram illustrating a state in which the sheet feeding tray 21 and the sheet separating device 51 according to the first embodiment are viewed from the arrow B in FIG. In FIG. 3, the end guide 21c is not shown for convenience.
As shown in FIG. 3, the sheet separating device 51 feeds the blower 511 that blows out high-pressure air, the duct 512 that blows air from the blower 511 into the paper feed tray 21, and the air blown by the duct 512. An air outlet 513 for blowing out toward the paper in the tray 21 and a blower output control unit (adjusting means, supply source control unit) 514 for controlling the output of the blower 511 are provided. The blower output control unit 514 constitutes a part of the control unit 11 (see FIG. 1).

The blower output control unit 514 performs control so that the output of the blower 511 sequentially changes. That is, the blower output control unit 514 continuously changes the air volume by controlling the power of the blower 511 variably. The blower output control unit 514 controls the air flow rate so as to change between 100% and 0% (substantially no wind) of the output capacity of the blower 511. By such control, the air volume can be pulsated.
Note that the blower output control unit 514 does not necessarily set the maximum air flow rate to 100% of the output capacity of the blower 511. The paper size (A4, etc.), the basis weight, the paper type (thick paper, etc.), etc. Depending on these conditions, a value of less than 100% may be considered. The specific parameters can be determined by actual experiments, thereby determining the air volume. In other words, the maximum air volume and the minimum air volume of the air, the cycle time for increasing / decreasing the air, and the like are determined by experiments or the like.

  Air from the air outlet 513 of the duct 512 passes through a notch 21e (see FIG. 2) provided in the paper feed tray 21 to the end surface of the paper placed on the bottom plate 21d in the paper feed tray 21. Blown out. More specifically, the high-pressure air from the blower 511 is blown out from the air outlet 513 so that the uppermost sheet (a plurality of overlapped sheets) among the sheets placed on the bottom plate 21d floats. In addition, the sheet that is levitated by the air can further rise beyond the position L at the upper end of the air outlet 513.

  Here, the floating height of the floating paper is determined according to the air volume. That is, when the air flow rate is low or absent, the levitated paper descends, while when the air flow rate is high, the paper rises and floats higher. As described above, the air volume of the blower 511 continuously increases and decreases by the blower output control unit 514. Accordingly, the sheet that is levitated by the air passes through the position L from the bottom to the top and passes from the top to the bottom. In this way, the sheet that is levitated by the air repeats vertical movement with respect to the position L at the upper end of the air outlet 513 as the air flow rate changes.

  In other words, when the air has a certain air volume, the sheet floats higher than the position L at the upper end of the air outlet 513 and is in a position where the air does not directly hit. By pulsating the air volume of the air to be blown and changing the floating position of the paper, the relative position between the edge of the floating paper and the boundary of the air blown to the paper edge can be moved sequentially in the paper stacking direction. It becomes possible.

FIG. 4 is an explanatory diagram for explaining a state in which a plurality of overlapping sheets P are separated one by one by air. Note that FIG. 4 illustrates a case where the overlap sheet P is composed of four sheets P1, P2, P3, and P4. In addition, it is assumed that the sheet P1 is positioned at the lowest position of the overlapped sheet P, and then is positioned in the order of the sheets P2, P3, and P4.
As shown in FIG. 4, when the superposed paper P that has floated higher than the position L due to air with a large air volume descends due to a decrease in the air air volume and is positioned below the position L, if it directly hits the superposed paper P until then, The air that does not exist directly hits the upper sheets P2, P3, and P4 in order from the lowermost sheet P1 of the overlapped sheet P.

  More specifically, when the superposed paper P passes through the position L from the top to the bottom, the paper separating operation is performed. That is, when the superposed paper P descends from the position L, as shown in FIG. 4, air flows between the paper P1 and the paper P2, and the paper P1 is separated. As it further descends, air flows between the paper P2 and the paper P3, and air flows between the paper P3 and the paper P4. By such an inflow of air, each of the sheets P1, P2, P3, and P4 of the overlapped sheet P is separated into one sheet.

  In addition, although the case where the overlapped paper P is separated at a time has been described, depending on the situation, it is also assumed that not all the sheets are separated at once. However, since the blower output control unit 514 controls the blower 511 so that the air volume from the air outlet 513 repeatedly increases and decreases, the sheet that has not been separated is separated by the subsequent separating operation. As described above, there is a case where the overlapped paper P is consequently separated by a plurality of separation operations. That is, the greater the number of passes through the position L, the greater the separation effect due to the sheet separation operation.

  As described above, in the first embodiment, there is no need to provide an air blocking means (shutter mechanism) or a direction changing means (air flow direction changing mechanism) between the air blowing means and the paper, so that it is inexpensive. It is possible to adopt a configuration that does not take up space, and it is possible to realize a sheet separating unit using stable air. In addition, since the paper feeding operation and the operation of changing the air blowing position can be performed independently, it can be used for a highly productive apparatus.

[Modification of First Embodiment]
FIG. 5 is a schematic configuration diagram showing the paper feed tray 21 according to a modification of the first embodiment together with the paper separating device 51, and is a plan view seen from the arrow A in FIG. FIG. 6 is a schematic configuration diagram illustrating a state in which the paper feed tray 21 and the paper separation device 51 are viewed from the arrow C in FIG. In FIG. 6, the side guides 21a are not shown for convenience.
As shown in FIG. 5, the paper feed tray 21 is configured so that not only the side guide 21 b but also the side guide 21 a can be moved according to the size of the paper. Other configurations of the paper feed tray 21 are the same as those in FIG.

Further, as shown in FIGS. 5 and 6, the paper separating device 51 is disposed on the side surface of the paper feed tray 21 where the feed roller 26 and the retard roller 27 are located. That is, the air outlet 513 of the paper separating device 51 is provided on the lead edge side of the paper.
In this way, the air outlet 513 of the paper separating device 51 may be provided on the side edge side of the paper as shown in FIGS. 2 and 3, and as shown in FIGS. It may be provided on the lead edge side.
Note that the configuration of the sheet separating device 51 is the same as that in the case of FIGS. 2 and 3, and the description thereof is omitted.
Other embodiments will be described below, but in these cases as well, as in the case of the first embodiment and its modifications, it may be provided on either the side edge side or the lead edge side of the paper. .

[Second Embodiment]
Next, a second embodiment will be described. In the second embodiment, a configuration different from that of the first embodiment is used as means for generating a pulsation in which the amount of air continuously changes.
FIG. 7 is a schematic configuration diagram illustrating a state where the paper feed tray 21 and the paper separating device 52 according to the second embodiment are viewed from the arrow B in FIG. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In addition, the configuration different from that of the first embodiment is only the sheet separating device 52.

  As shown in FIG. 7, the sheet separating device 52 blows high-pressure air from a blower 521, and blows air from the blower 521 into the paper feed tray 21, and an opening 522 a is formed at an intermediate portion in the blowing direction. Duct 522. The sheet separating device 52 includes an air blowing port 523 for blowing the air blown by the duct 522 toward the sheet in the sheet feeding tray 21, and a shutter opening / closing mechanism (not shown) provided in the duct 522. ing.

  The shutter opening / closing mechanism (not shown) has a shutter 524 for opening and closing the opening 522a of the duct 522. The shutter 524 is slid by driving means (not shown) to continuously change the opening area of the opening 522a. For this reason, when the opening 522a is opened, a part of the air blown through the duct 522 is discharged from the opening 522a, not from the air outlet 523. A driving unit (not shown) for driving the shutter 524 is controlled by a shutter control unit (not shown). This shutter control unit constitutes a part of the control unit 11 (see FIG. 1).

Here, the shutter 524 continuously changes the opening area of the opening 522a by the slide reciprocating operation, and fully opens and closes the opening 522a. That is, when the opening 522a is opened by the sliding reciprocation of the shutter 524, a part of the air is discharged therefrom. When the amount of discharged air is large, the amount of air blown from the air blowing port 523 is reduced. When the amount of air discharged from the opening 522a is small, the air is blown from the air blowing port 523. Increases the amount of air. Furthermore, when the opening 522a is fully closed, the amount of air blown from the air blowing port 523 is the maximum, and when the opening 522a is fully opened, the amount of air blown from the air blowing port 523 is Is the smallest.
Thus, the amount of air blown out from the air outlet 523 can be reduced by sliding the shutter 524 back and forth without controlling the output of the blower 521. Then, by continuously changing the amount of air, the air pulsates, and the floating sheet can be moved up and down with respect to the position L at the upper end of the air outlet 523. For this reason, according to the present embodiment, the sheet separating device 52 can be configured easily.

[Third Embodiment]
Next, a third embodiment will be described. Also in the third embodiment, a configuration different from the first embodiment and the second embodiment is used as means for generating a pulsation in which the amount of air continuously changes.
FIG. 8 is a schematic configuration diagram illustrating a state in which the sheet feeding tray 21 and the sheet separating device 53 according to the third embodiment are viewed from the arrow B in FIG.
As shown in FIG. 8, the paper separating device 53 feeds the blower 531 that blows out high-pressure air, the duct 532 that blows the air from the blower 531 into the paper feed tray 21, and the air blown by the duct 532. An air outlet 533 for blowing out toward the paper in the tray 21 and a shutter opening / closing mechanism (not shown) provided in the duct 532 are provided.

A shutter opening / closing mechanism (not shown) includes a shutter 534 that slides and reciprocates so as to be slid by a driving means (not shown) to continuously change the cross-sectional area of the flow path in the duct 532. For this reason, even if the blower 531 supplies air with a constant air volume to the duct 532, the amount of air blown from the air outlet 533 can be continuously increased and decreased by the reciprocating motion of the shutter 534. . As a result, the floating sheet can be moved up and down with respect to the position L at the upper end of the air outlet 533.
A driving unit (not shown) for driving the shutter 534 is controlled by a shutter control unit (not shown). This shutter control unit constitutes a part of the control unit 11 (see FIG. 1).

  The shutter 534 is configured to be able to fully close the flow path. For this reason, even if the blower 531 is not particularly stopped, it is possible to prevent air from being blown out from the air blowing port 533 by the shutter 534 fully closing the flow path. More specifically, in the case of the first embodiment, the blower 511 (see FIG. 3) must be stopped for a while before the air can be prevented from blowing out from the air outlet 513 (see FIG. 3). . On the other hand, in the case of the third embodiment, if the flow path of the duct 532 is closed by the shutter 534, the air can be prevented from being immediately blown out from the air outlet 533. Therefore, according to the third embodiment, the followability when air is blown out from the air outlet 533 can be improved.

[Fourth Embodiment]
Next, a fourth embodiment will be described. In the fourth embodiment, another configuration is used as means for generating pulsations in which the amount of air continuously changes.
FIG. 9 is a schematic configuration diagram illustrating a state in which the sheet feeding tray 21 and the sheet separating device 54 according to the fourth embodiment are viewed from the arrow B in FIG.
As shown in FIG. 9, the paper separating device 54 blows high-pressure air from a blower 541 and blows air from the blower 541 into the paper feed tray 21, and an opening 542 a is formed at an intermediate portion in the blowing direction. Duct 542. In addition, the sheet separating device 54 includes an air blowing port 543 for blowing the air blown by the duct 542 toward the sheet in the sheet feeding tray 21, and an opening / closing mechanism 544 for opening and closing the opening 542a of the duct 542. It is equipped with.

  The opening / closing mechanism 544 includes a link (connecting portion) 544 a on which the intermediate portion m is pivotally supported, an opening / closing valve 544 b that is positioned inside the duct 542, and is attached to one end of the link 544 a, and above the paper tray 21. And a stopper 544c attached to the other end of the link 544a. One end of the link 544a is urged in the direction of arrow f (upward) by a spring member (connecting portion) (not shown). Therefore, the on-off valve 544b normally closes the opening 542a of the duct 542. is doing.

  The stopper 544c is disposed at the end of the paper at the air blowing position. It can also be said that the position where the stopper 544c is arranged is a portion where the movement of the paper is the most intense due to the blowing of air. Further, the position of the stopper 544c in the height direction is disposed above the position L of the upper end of the air outlet 543.

  When the sheet floated by the air from the air outlet 543 rises beyond the position L and contacts the stopper 544c, the stopper 544c is pressed upward by the sheet. When the stopper 544c is pressed upward, the other end of the link 544a moves upward. Along with this, one end of the link 544a moves downward, and the on-off valve 544b also moves downward. As a result, the opening 542a that has been closed by the on-off valve 544b until then is opened. Then, the air in the duct 542 is discharged from the opening 542a, and the amount of air blown out from the air outlet 543 decreases. Then, the sheet that has floated descends, and the sheet that has been pressing the stopper 544c up until then is separated from the stopper 544c. In other words, the levitated paper descends below the position L.

  When the sheet no longer presses the stopper 544c upward, the stopper 544c moves downward and returns to the normal position. The on-off valve 544b moves upward to close the opening 542a. Then, the amount of air discharged from the opening 542a decreases, so that the amount of air discharged from the air outlet 543 increases. For this reason, the sheet floating below the position L starts to rise above the position L. Thus, it can be said that the configuration in the fourth embodiment is a mechanism having an autonomous action in the sense that the floated sheet itself acts to adjust the air volume.

  In the fourth embodiment, since the opening / closing mechanism 544 is configured as described above, the floating sheet can be moved up and down with respect to the position L at the upper end of the air outlet 543 with a simple configuration. .

[Fifth Embodiment]
Next, a fifth embodiment will be described. In the fifth embodiment, a configuration in which a restricting portion for restricting the floating height of the sheet is added.
FIG. 10 is a schematic configuration diagram illustrating a state in which the paper feed tray 21 and the paper separating device 55 according to the fifth embodiment are viewed from the arrow C in FIG.
As shown in FIG. 10, the paper separating device 55 feeds the air blown from the blower (not shown) that blows out high-pressure air, the duct (not shown) that blows air from the blower into the paper feed tray 21, and the air blown by the duct. An air outlet 553 for blowing out toward the paper in the tray 21 and a regulating portion (stopper) 554 that is positioned above the paper feed tray 21 and regulates the floating height of the paper are provided. The restricting portion 554 is provided higher in the paper stacking direction than the position L at the upper end of the air outlet 553.
The paper separating device 55 includes means (not shown) for pulsating the amount of air blown from the air blowout port 553, and the means is the first to fourth embodiments described above. Can be used.

  In the fifth embodiment, since the regulation unit 554 that regulates the flying height of the paper is provided, the floated paper rises according to the air volume, and when the air volume reaches a certain level, the uppermost paper is the regulation unit 554. Abut. By pulsating the air in this state, the uppermost sheet moves up and down between the position of the restricting portion 554 and the range where the air from the air outlet 553 hits. Therefore, the floating sheet can be moved up and down with respect to the position L.

[Sixth Embodiment]
Next, a sixth embodiment will be described. In the sixth embodiment, as in the case of the fifth embodiment, a restriction unit for restricting the floating height of the paper is added. However, the fifth method is to restrict the floating height of the paper. This is different from the embodiment.
FIG. 11 is a schematic configuration diagram illustrating a state in which the paper feed tray 21 and the paper separating device 56 according to the sixth embodiment are viewed from the arrow C in FIG.
As shown in FIG. 11, the sheet separating device 56 feeds air blown by a duct (not shown) that blows out high-pressure air, a duct (not shown) that blows air from the blower into the paper feed tray 21, and air blown by the duct. An air outlet 563 for blowing out toward the paper in the tray 21 and a restricting portion (stopper) 564 that is located above the paper feed tray 21 and restricts the floating height of the paper are provided.

The restricting portion 564 includes a member where the restricting portions are separated from each other. In other words, the restricting portion 564 is spaced apart from the air outlet 563 in a direction perpendicular to the sheet stacking direction, and is provided at substantially the same height. An air outlet 563 is disposed between the restricting portions 564.
The separation distance s of the restricting portion 564 is a dimension that allows the portion of the paper directly hit by the air blown out from the air blowing port 563 to float. That is, in the case of the sixth embodiment, the entire sheet is not lifted at substantially the same height by air, but the portion of the sheet located in the vicinity of the air outlet 563 is lifted higher. is doing. The lower surface of the restricting portion 564 is positioned below the position L at the upper end of the air outlet 563. Note that the separation distance s may be appropriately determined according to the type of paper through experiments and the like.

  In the sixth embodiment, because it is configured as described above, the edge of the portion of the paper to which air is blown is deformed upward by the force of air, and the position L of the upper end of the air outlet 563 is caused by the air volume. It will be deformed to a state where it is located above. In this state, the sheet can be moved up and down while partially deforming the position L at the upper end of the air outlet 563 by pulsating the air. In this way, the amount of deformation of the paper is controlled by pulsating by the air outlet 563.

[Seventh Embodiment]
Next, a seventh embodiment will be described. In the seventh embodiment, a restricting portion for restricting the flying height of the sheet is added, and means for biasing the sheet in contact with the restricting portion downward is provided.
(A) of FIG. 12 is a schematic configuration diagram illustrating a state in which the paper feed tray 21 and the paper separating device 57 according to the seventh embodiment are viewed from the arrow C in FIG. 5, and (b) of FIG. It is the schematic block diagram seen from the direction of arrow XIIb of a).
As shown in FIG. 12A, the paper separating device 57 is blown by a blower (not shown) that blows out high-pressure air, a duct (not shown) that blows air from the blower into the paper feed tray 21, and a duct. An air outlet 573 for blowing air toward the paper in the paper feed tray 21, a restricting portion (stopper) 574 that is located above the paper feed tray 21 and restricts the floating height of the paper, and a restricting portion 574 And an urging portion 575 as a spring member for pushing back the paper when the paper is pressed upward by the paper.

  As shown in FIG. 12B, an urging portion 575 is attached to an intermediate portion of the restricting portion 574. Further, the restricting portion 574 has one end 574a rotatably held on the image forming apparatus main body 10 (see FIG. 1) side, and a restricting portion 574 serving as a stopper that restricts a rotation range provided on the image forming apparatus main body 10 side (not shown). Is placed so that the initial position of the other end 574b is between the upper end and the lower end of the air outlet 573. More specifically, one end 574a of the restricting portion 574 is located higher in the paper stacking direction than the position L at the upper end of the air outlet 573, and the other end 574b of the restricting portion 574 is located below the position L. . As described above, the restriction portion 574 that restricts the flying height of the sheet by the elastic force is installed so that the initial position is between the upper end and the lower end of the air outlet 573.

  For this reason, the restricting unit 574 presses the sheet floated by air downward. In other words, the paper in the paper feed tray 21 is lifted by the other end 574 b of the restricting portion 574 and comes into contact with the restricting portion 574. As the air volume increases, the uppermost sheet floats against the pressing force of the restricting portion 574. As the floated sheet rises, the pressing force received from the restricting portion 574 increases and is regulated at a position that balances with the lift force by air. When the air volume decreases due to pulsation, it descends. Since the descending sheet receives a pressing force from the regulating unit 574, the sheet descends more quickly than in the case of natural fall. That is, by forcibly lowering the paper, the cycle of the vertical movement of the paper can be shortened, and it becomes easy to cope with a high-speed machine.

  As described above, when the air flow rate from the air outlet 573 increases, the restricting portion 574 is displaced upward by the force from the paper that comes into contact with the restricting portion 574. Conversely, when the air flow rate decreases, the restricting portion 574 decreases. Descends. Therefore, it is possible to move the uppermost sheet in contact with the restricting portion 574 up and down with respect to the position L at the upper end of the air outlet 573 by air pulsation.

[Eighth Embodiment]
Next, an eighth embodiment will be described. In the eighth embodiment, as in the case of the seventh embodiment, a restricting portion for restricting the flying height of the sheet is added, and a means for urging the sheet in contact with the restricting portion downward is provided. It is a configuration. In addition, the eighth embodiment is a combination of the configuration of the sixth embodiment and the configuration of the seventh embodiment.
FIG. 13 is a schematic configuration diagram illustrating a state in which the paper feed tray 21 and the paper separating device 58 according to the eighth embodiment are viewed from the arrow C in FIG.
As shown in FIG. 13, the paper separating device 58 feeds the air blown from the blower (not shown) that blows out high-pressure air, the duct (not shown) that blows air from the blower into the paper feed tray 21, and the air blown by the duct. An air outlet 583 for blowing out toward the paper in the tray 21, a restricting portion (stopper) 584 that is located above the paper feed tray 21 and restricts the floating height of the paper, and the restricting portion 584 is located above the paper. And an urging portion 585 as a spring member for pushing the paper back downward when pressed.

The restricting portions 584 are arranged apart from each other, and an air blowing port 583 is arranged therebetween. Due to the air blowing from the air blowing port 583, the portion of the paper located in the vicinity thereof is lifted higher.
Further, the lower surface of the restricting portion 584 is usually positioned below the position L at the upper end of the air outlet 583 due to the pressing of the urging portion 585. When the sheet floats, the lower surface of the restricting portion 584 may be positioned above the position L accordingly.
In this way, in the eighth embodiment, it is possible to control the amount of deformation of the paper and shorten the cycle of vertical movement of the paper.

[Ninth Embodiment]
Next, a ninth embodiment will be described. In the ninth embodiment, a restricting portion that restricts the flying height of the sheet and presses the sheet downward by its own weight is added.
FIG. 14A is a schematic configuration diagram showing the state of the paper feed tray 21 and the paper separating device 59 according to the ninth embodiment as viewed from the arrow C in FIG. 5, and FIG. It is the schematic block diagram seen from the direction of arrow XIVb of a).
As shown in FIG. 14A, the sheet separating device 59 is blown by a blower (not shown) that blows out high-pressure air, a duct (not shown) that blows air from the blower into the paper feed tray 21, and a duct. An air outlet 593 for blowing air toward the paper in the paper feed tray 21 and a restricting portion (stopper) 594 that is located above the paper feed tray 21 and regulates the floating height of the paper are provided. Yes.

  As shown in FIG. 14B, one end 594a of the restricting portion 594 is rotatably held on the image forming apparatus main body 10 (see FIG. 1) side, and is provided on the image forming apparatus main body 10 (not shown). A part of the restricting portion 594 is brought into contact with a stopper that limits the range so that the initial position of the other end 594b is between the upper end and the lower end of the air outlet 573. The restricting portion 594 can be formed of, for example, aluminum or stainless steel (SUS) having a certain weight. For this reason, the restricting unit 594 presses the paper in the paper feed tray 21 and always presses the paper with a constant pressing force even while the paper is levitated by the air from the air outlet 593. That is, in the ninth embodiment, the restricting portion 594 configured to restrict the flying height of the sheet is configured to be displaceable in the sheet stacking direction while applying a constant force due to its own weight to the sheet. As in the case of the seventh and eighth embodiments, it is not necessary to provide the urging unit 575 (see FIG. 12) or the urging unit 585 (see FIG. 13). Therefore, it is possible to obtain the same effects as in the seventh and eighth embodiments with a simple configuration.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. FIG. 2 is a schematic configuration diagram viewed from an arrow A in FIG. 1, showing a paper feed tray according to the first embodiment together with a paper separating device. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 1st Embodiment from the arrow B of FIG. It is explanatory drawing explaining a mode that the superposition | polymerization sheet | seat which consists of several sheets is separated one by one with air. It is a schematic block diagram which shows the paper feed tray which concerns on the modification in 1st Embodiment with a paper separation apparatus. FIG. 6 is a schematic configuration diagram illustrating a state where the paper feed tray and the paper separation device are viewed from the arrow C in FIG. 5. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 2nd Embodiment from the arrow B of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 3rd Embodiment from the arrow B of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 4th Embodiment from the arrow B of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 5th Embodiment from the arrow C of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 6th Embodiment from the arrow C of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 7th Embodiment from the arrow C of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 8th Embodiment from the arrow C of FIG. It is a schematic block diagram which shows the state which looked at the paper feed tray and paper separation apparatus which concern on 9th Embodiment from the arrow C of FIG.

Explanation of symbols

21, 22, 23, 24 ... paper feed tray, 25 ... nudger roller, 26 ... feed roller, 27 ... retard roller, 51, 52, 53, 54, 55, 56, 57, 58, 59 ... paper separating device, 513 523, 533, 543, 553, 563, 573, 583, 593 ... Air outlet, 554, 564, 574, 584, 594 ... Restriction part, 575, 585 ... Biasing part, L ... Position, P ... Superposition paper

Claims (3)

A loading section for loading paper;
A paper handling unit that has a blowout opening that opens to face the side of the sheet bundle stacked on the stacking unit, and blows air toward the side of the sheet bundle from the blowout opening to float the paper;
A sending unit that sends out in order from the upper sheet that is separated by the sheet separating unit among the bundle of sheets stacked on the stacking unit;
Only including,
The paper separating section is
A control unit for controlling the air volume from the blowout port so that the floating position of the paper blown and floated from the blowout port moves up and down the upper end of the blowout port;
One end portion that is rotatably held by the apparatus main body so as to be displaceable in the stacking direction of the sheets stacked on the stacking section is located above the upper end of the outlet and is provided in the apparatus main body. The other end, which is in contact with the stopper and whose rotation range is limited, is installed so that the initial position is between the upper end and the lower end of the air outlet on the stacking part, and air is blown from the air outlet to float. A regulation unit that regulates the floating height of the paper to be
It is provided between the one end and the other end of the restricting portion, and is loaded on the loading portion so that the other end of the restricting portion is located between the upper end and the lower end of the outlet. An urging portion for urging the regulating portion with an elastic force in the direction of the paper being
Have
A position where the sheet floats against the pressing force of the restricting portion as the air volume blown from the outlet increases and the pressing force received from the restricting portion increases as the sheet rises to balance the lift force by air The sheet feeding device is characterized in that the sheet regulated at the balance position is lowered while receiving a pressing force from the regulating portion as the air volume blown out from the blowing port decreases . A loading section for loading paper;
A paper handling unit that has a blowout opening that opens to face a side surface of the sheet bundle stacked on the stacking unit, and blows air toward the side surface of the sheet bundle from the blowout opening to float the paper;
A supply source for supplying air to the paper separating section;
A sending section for sending one by one from the upper-level sheets separated by the sheet separating section among the bundle of sheets stacked on the stacking section;
Image forming means for forming an image on a sheet sent by the sending unit;
Including
The paper separating section is
A control unit for flotation position of the paper to be levitated by the air of said source from said outlet to control the air volume of air from the air outlet so as to lower the upper end of the outlet,
One end portion that is rotatably held by the apparatus main body so as to be displaceable in the stacking direction of the sheets stacked on the stacking section is located above the upper end of the outlet and is provided in the apparatus main body. other end initial position the outlet of the installed air of the supply source to be between the upper end and the lower end of the outlet at the top of the stacking section where the stopper abuts the rotation range is restricted A regulation unit that regulates the floating height of the paper that is blown and floated from
It is provided between the one end and the other end of the restricting portion, and is loaded on the loading portion so that the other end of the restricting portion is located between the upper end and the lower end of the outlet. An urging portion for urging the regulating portion with an elastic force in the direction of the paper being
I have a,
A position where the sheet floats against the pressing force of the restricting portion as the air volume blown from the outlet increases and the pressing force received from the restricting portion increases as the sheet rises to balance the lift force by air The image forming apparatus is characterized in that the sheet regulated at the balance position is lowered while receiving a pressing force from the regulating unit as the air volume blown from the blowout port decreases . The image forming apparatus according to claim 2 , further comprising a supply source control unit that changes an air supply amount of the supply source according to information on a sheet mounted on the stacking unit.

Images