JP2018188272A - Paper feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device and an image forming device capable of stably feeding paper even under a condition on which the paper is hard to float.SOLUTION: A paper feeding device including a paper loading base 511 for storing sheets of paper in a stacked state, a separation air blowing part 52 for blowing air from a tip side of the stacked sheets of paper in a paper feeding direction, floating air blowing parts 53 and 54 provided at both sides of a direction parallel to the surface of the stacked sheets of paper and orthogonal to the paper feeding direction to blow air to the paper, a suction part 56 for sucking the floated paper on an uppermost part, wind direction switching members 534 and 544 for switching a wind direction in the floating air blowing part to an arbitrary direction from a direction toward a tip side of the stacked sheets of paper in the paper feeding direction over to a direction toward a rear end side thereof, and a control unit 400 for controlling switching in a wind direction in the floating air blowing part by the wind direction switching member according to at least one of a basis weight and a size of the paper and a floating state thereof.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet feeding device and an image forming apparatus.

2. Description of the Related Art Conventionally, in an image forming apparatus that forms an image on paper, an air suction type paper feeding device that stocks paper in a stacked state and supplies the paper to an image forming unit is known.
The air suction type paper feeding device includes a floating air blowing unit that blows air to the upper paper from both sides along a direction perpendicular to the paper conveyance direction with respect to the paper stacked on the paper stacking unit, and Paper is separated by a separation air blower that blows air from the leading edge in the conveyance direction of the uppermost sheet and separates the uppermost sheet from other sheets, and a conveyance belt disposed above the stacked sheets. A belt transport mechanism that feeds the toner in the transport direction while adsorbing the ink. By adsorbing only the uppermost sheet by these mechanisms and reliably separating it from other sheets, the sheets can be sent out one by one on the sheet conveyance path.

However, when the paper is heavy or large, the flying force by the flying air and the separation air is not sufficient, and the paper may not be sent out.
With respect to such a problem, Patent Document 1 discloses a technique for improving the levitation force by blowing air in a direction in which the levitation air and the separation air collide with each other. At this time, since the floating state of the sheet may become unstable due to the collision of air, a mechanism for sucking air from the rear end side of the sheet is provided.

JP 2014-169182 A

It is necessary to blow strong floating air under conditions where the paper does not easily float. Using the invention described in Patent Document 1, the collision of air further increases, and accompanying this, strong suction force from the rear end side. It is necessary to suck air.
However, if the suction force is increased, the sheet may be sucked carelessly, so that it becomes difficult to stabilize the airflow while maintaining the strength of the air.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device and an image forming apparatus that can stably feed a sheet even under a condition in which the sheet hardly floats.

In order to solve the above problem, a paper feeding device according to claim 1 is provided.
A paper stacking unit for storing paper in a stacked state;
A separation air blower that blows air onto the paper from the leading edge in the paper feeding direction of the loaded paper;
A floating air blower that blows air from both sides of the paper edge perpendicular to the paper feeding direction of the loaded paper;
An adsorbing part that adsorbs the uppermost sheet that has floated;
A wind direction switching unit that changes a blowing direction of the floating air blowing unit in an arbitrary direction from a direction toward a leading end side in a paper feeding direction of stacked sheets to a direction toward a rear end side; and
A control unit that controls a change in the blowing direction of the floating air blowing unit by the wind direction switching unit according to at least one of the basis weight and size of the sheet and the floating state of the sheet. .

The invention according to claim 2 is the paper feeding device according to claim 1,
Equipped with a floating detection unit that detects the floating of the loaded paper,
The controller is
When the floating detection unit detects the floating of the sheet, the blowing direction of the floating air blowing unit is changed to a direction toward the rear end side in the sheet feeding direction of the stacked sheets.

The invention according to claim 3 is the paper feeding device according to claim 1 or 2,
Equipped with a floating detection unit that detects the floating of the loaded paper,
The controller is
When the floating detection unit does not detect the floating of the paper within a predetermined period from the start of paper feeding, the blowing direction of the floating air blowing unit is changed to the direction toward the front end side of the stacked paper feeding direction. It is characterized by.

According to a fourth aspect of the present invention, in the paper feeding device according to any one of the first to third aspects,
The floating air blowing section is movable in a direction parallel to the surface of the stacked paper and orthogonal to the paper feeding direction.

The invention according to claim 5 is the paper feeding device according to any one of claims 1 to 4,
The floating air blowing section blows air obliquely upward with respect to the sheet surface.

The image forming apparatus according to claim 6,
A sheet feeding device according to any one of claims 1 to 5,
And an image forming unit that forms a toner image on a sheet.

  According to the present invention, it is possible to provide a sheet feeding device and an image forming apparatus that can stably feed a sheet even under a condition in which the sheet hardly floats.

1 is a diagram illustrating a schematic configuration of an image forming apparatus. 2 is a block diagram illustrating a main functional configuration of the image forming apparatus. FIG. 2 is a perspective view of a sheet feeding unit of the image forming apparatus. FIG. FIG. 4 is a partially cutaway side view showing a delivery unit, a suction unit, and a conveyance unit of a paper feeding unit. It is a top view which shows operation | movement of the wind direction switching member of a paper feed part. It is a top view which shows the sending part, adsorption | suction part, and conveyance part of a paper feed part. FIG. 10 is a side view illustrating a sheet state in a sheet feeding operation of a sheet feeding unit. It is a top view explaining the blowing direction of floating air. 3 is a flowchart illustrating an operation of the image forming apparatus.

  Embodiments according to the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

[Configuration of image forming apparatus]
FIG. 1 is an overall configuration diagram of an image forming apparatus 100 according to the present invention, and FIG. 2 is a block diagram showing a functional configuration of the image forming apparatus 100.
As shown in FIGS. 1 and 2, the image forming apparatus 100 mainly includes an image forming apparatus main body 100a, an image reading apparatus SC, an automatic document feeder DF, an image processing unit 30, a paper feeding device 500, a control unit 400, and a storage. The unit 410 and the communication unit 420 are configured.

The image forming apparatus main body 100a includes an image forming unit 10 including a photoreceptor 1, a charging unit 2, an image exposing unit 3, a developing unit 4, a transfer unit 5, a cleaning unit 6 and the like, a fixing unit 7, and a paper transport system. Has been. The paper transport system includes a first paper feed unit 11, a second paper feed unit 12, a paper feed cassette 13, a paper discharge unit 14, a transport path switching unit 15, a circulation refeed unit 16, and a reverse paper discharge unit 17. ing.
The paper feeding device 500 includes three paper feeding units 50 that are arranged side by side.

(1) Image Processing Unit The image processing unit 30 performs various types of image processing on the image data and transmits an image signal to the image forming unit 10.
A document d placed on the document table of the automatic document feeder DF is read on one or both sides by the optical system of the image reading device SC and read by the image sensor CCD. The image processing unit 30 performs analog processing, A / D conversion, shading correction, image compression processing, and the like on the analog signal photoelectrically converted by the image sensor CCD, and then sends the image signal to the image exposure unit 3.
The control unit 400 can communicate with an external device (for example, a personal computer) connected to the communication network from the communication unit 420, and the image processing unit 30 can control the external device under the control of the control unit 400. An image signal received from the apparatus may be sent to the image exposure unit 3.

(2) Image Forming Unit In the image forming unit 10, a charge is added to the photoreceptor 1 by the charging unit 2, and an electrostatic latent image is formed by laser light irradiation from the image exposure unit 3. The electrostatic latent image is visualized to become a toner image. Next, the paper P stored in the paper feed cassette 13 is conveyed from the first paper feed unit 11. The sheet P is conveyed in synchronization with the toner image by the second sheet feeding unit 12 formed of a registration roller. Thereafter, the paper P is fixed by the fixing unit 7 after the toner image is transferred by the transfer unit 5. Note that the toner remaining on the photosensitive member 1 is removed by the cleaning unit 6.
Further, not the paper P stored in the paper feeding cassette 13 but also the paper P stored in the paper feeding device 500 is fed to the image forming apparatus main body 100a, and the toner image is transferred to the paper P and fixed. .

  The paper P after fixing is discharged out of the apparatus by the paper discharge unit 14. In the case of duplex printing, the paper P on which the image is formed on the first surface is sent to the circulation refeed unit 16 by the conveyance path switching unit 15 and reversed, and the image forming unit 10 again forms an image on the second surface. After formation, the paper is discharged out of the apparatus by the paper discharge unit 14. In the case of reverse paper discharge, the paper P branched from the normal paper discharge path is switched back and upside down in the reverse paper discharge unit 17 and then discharged out of the apparatus by the paper discharge unit 14.

(3) Paper Feeding Device FIG. 3A is a perspective view showing an outline of the paper feeding unit 50 of the paper feeding device 500. As described above, the three sheet feeders 50 are arranged in the sheet feeder 500 in the vertical direction. Since these are all configured in the same way, only one sheet feeder 50 will be described here. Assumed to be performed.

The paper feed unit 50 includes a paper stacking base 511 as a horizontally oriented paper stacking unit on which a plurality of papers P are stacked, and behind the paper stacking base 511, that is, upstream of the paper feeding direction a. The rear end regulating member 512 provided and the front end regulating member 513 provided in front of the paper stacking base 511, that is, downstream in the paper feeding direction a are provided.
In the following description of the paper feeding unit 50, the left hand direction is “left” and the horizontal direction perpendicular to the paper feeding direction a is a horizontal direction perpendicular to the paper feeding direction a and facing the paper feeding direction a. The right hand direction is “right” in the state where the paper feeding direction “a” is directed.

The paper stacking base 511 is supported so as to be movable up and down in the paper feed unit 50, and the rear end regulating member 512 and the front end regulating member 513 are fixedly installed in the paper feed unit 50.
The upper end portion of the front end regulating member 513 is somewhat lower in height than the upper end portion of the rear end regulating member 512. On the other hand, the sheet stacking table 511 is moved up and down by an actuator (not shown), and the uppermost portion of the sheets P stacked on the sheet stacking table 511 maintains a specified height that is slightly lower than the upper end of the leading edge regulating member 513. As described above, the actuator is controlled by the control unit 400. The height control by the actuator is performed based on sensing of a sensor (not shown) that detects the height of the uppermost sheet P provided on the rear end regulating member 512 side.
Further, the sheet stacking table 511 can be lowered when the sheet P is not supplied, such as when the sheet P is replenished.

A separation air blower 52 is provided adjacent to the leading edge regulating member 513 and downstream of the leading edge regulating member 513 in the paper feeding direction a. In addition, floating air blowing units 53 and 54 are provided on the left and right sides of the paper stacking base 511, respectively, and the inner side surfaces of the floating air blowing units 53 and 54 are flat and run in the vertical direction. It functions as a regulating member that regulates the position in the left-right direction.
The floating air blowing units 53 and 54 are provided so as to be movable in the left-right direction by an actuator (not shown) so that the wall surfaces of the floating air blowing units 53 and 54 are in contact with the end portions in the width direction of the paper. The actuator is controlled by the control unit 400. Note that the position in the left-right direction by the actuator is determined based on the size information of the sheets stacked on the sheet feeding unit 50 stored in the storage unit 410.

  Blower fans 521, 531, and 541 are provided inside the separation air blower 52 and the floating air blowers 53 and 54, respectively, and are configured to blow air from the blower ports 522, 532, and 542.

FIG. 3B is a main part configuration diagram of the floating air blowing unit 54. In addition, since the floating air blowing unit 53 has the same configuration as the floating air blowing unit 54, a configuration diagram of main parts thereof is omitted.
As shown in FIG. 3 (B), the floating air blowing sections 53 and 54 are arranged in a horizontal direction or more than the horizontal direction from the left and right sides of the uppermost sheet P positioned at the regulated height toward the sheet P. Nozzles 533 and 543 are provided for blowing air in a direction inclined upward. The air blowing ports 532 and 542 of the nozzles 533 and 543 are formed so that the upper edge portion thereof is lower than the uppermost sheet P positioned at the regulated height.

As shown in FIG. 3, the floating air blowing units 53 and 54 include wind direction switching members 534 and 544, shafts 535 and 545, gear pairs 536 and 546, and motors 537 and 547, respectively.
The air direction switching members 534 and 544 are disposed between the air blowing ports 532 and 542 and the stacked sheets, and are provided to be rotatable about shafts 535 and 545. The driving force by the motors 537 and 547 is transmitted to the shafts 535 and 545 by the gear pairs 536 and 546, and the shafts 535 and 545 rotate. Note that the wind direction switching members 534 and 544 are formed so that the upper edge portion thereof is higher than the uppermost sheet P located at the regulated height.
That is, air is blown from the air blowing ports 532 and 542 and the upper paper is guided by the air direction switching members 534 and 544 so that the floating air is blown obliquely upward against the paper surface of the upper paper P in the stacked state. It is possible to raise P.

FIG. 4 is a cross-sectional view showing a configuration around the front end of the uppermost sheet P in the sheet feeding direction a in the sheet stacking table 511.
The separation air blowing unit 52 includes a nozzle 523 for blowing air from the blowing port 522 toward a direction slightly inclined upward from the downstream side of the paper feeding direction a, and the floating air blowing units 53 and 54. The air is blown to the downstream end in the paper feeding direction a of the plurality of sheets that have floated due to the air, so that air is blown between the floated sheet P and the other sheets, and the sheets other than the uppermost sheet P are separated. It is possible to descend.

FIG. 5 shows the relationship between the direction of the wind direction switching member 544 and the blowing direction.
Hereinafter, a direction perpendicular to the sheet feeding direction a on the sheet surface is defined as a left-right direction b, and a side surface connected to the shaft 545 among the side surfaces of the wind direction switching member 544 is defined as a rotation surface 544a.
For example, as shown in FIG. 5A, when the rotating surface 544a stops at an angle (θ1) of 90 degrees with respect to the left-right direction b, the flying air is directed from the blower port 542 in a direction orthogonal to the paper feeding direction a. Blown out.
On the other hand, as shown in FIG. 5B, when the rotation surface 544a stops at an angle (θ2) directed to the rear end side of the sheet with respect to the left-right direction b, It blows out toward the upstream side (the rear end side of the paper).
As shown in FIG. 5C, when the rotation surface 544a stops at an angle (θ3) directed to the front end side of the sheet with respect to the left-right direction b, the downstream side ( Blows out toward the leading edge of the paper.
That is, by driving the motors 537 and 547 under the control of the control unit 400 and rotating the wind direction switching members 534 and 544, the blowing direction of the floating air is changed.

  FIG. 6 is a plan view of the delivery unit 55 and the suction unit 56. As shown in FIGS. 3, 4, and 6, a sending unit 55 is provided above the sheet stacking table 511. In FIG. 3, the sending unit 55 is shifted to the position indicated by the arrow so that the surrounding configuration is not hidden, but actually, as shown in FIG. 4, the feeding direction a of the sheet stacking table 511 It is arrange | positioned above the downstream edge part.

The sending unit 55 includes four belts 556 arranged in the left-right direction perpendicular to the paper feeding direction a on the paper feeding surface, a motor 551 serving as a paper feeding drive source for driving these belts 556, and each belt 556 and motor 551. A transmission gear train 552 interposed therebetween.
Each belt 556 includes a large-diameter roller 553 provided on the upstream side in the paper feeding direction a, two small-diameter rollers 554 and 555 provided on the downstream side in the paper feeding direction a, and these rollers 553 and 554. , 555, and a belt 556. Torque is applied from the motor 551 to the large-diameter roller 553 of each belt mechanism in a direction in which the lower portion of each belt 556 advances in the paper feeding direction a. A sprocket may be used instead of the rollers 553, 554, and 555.
Each belt 556 is formed with a plurality of small holes penetrating the front and back over the entire surface, and the sheet P is placed under each belt 556 through the small holes by suction of the suction portion 56 described later. It is possible to adsorb.

At the upstream side of the belt 556 in the paper feeding direction “a”, a suction detection unit 557 that detects the suction of the paper with respect to each belt 556 is provided. The adsorption detection unit 557 includes a substantially rod-shaped detection body 557a supported so as to be swingable, and a light-sensitive sensor 557b.
One end of the detection body 557a protrudes below the lower portion of the belt 556. When the paper P is attracted to the belt 556, the detection body 557a swings and the one end thereof is pushed back upward. Yes. The other end portion of the detection body 557a is lowered when the one end portion is pushed back upward, and the sensor 557b is arranged to shield the sensor 557b. The sensor 557b controls the change in the amount of received light due to the shielding. To cause the control unit 400 to recognize the suction of the paper P.

As shown in FIGS. 3, 4, and 6, the suction portion 56 includes a duct 561 arranged with one end portion being inserted inside each belt 556 of the delivery portion 55, and the other end portion of the duct 561. And a fan 562 that makes the inside of the duct 561 have a negative pressure.
The duct 561 is formed in a substantially rectangular parallelepiped shape at one end inserted into each belt 556, and an opening 561a is formed in the lower part thereof. And the inside of the duct 561 is made into a negative pressure by the fan 562, so that the outside air can be sucked from the opening 561a.
The duct 561 is arranged so that the opening 561a straddles the lower part of the four belts 556, and the range corresponding to the opening 561a of each belt 556 is a suction region B for the sheet.

  With the above configuration, the sending unit 55 and the suction unit 56 are lifted by the suction force generated in the suction region B when the upper sheet P on the sheet stacking table 511 is lifted by the above-described blowing air blowing units 53 and 54. The uppermost paper P is attracted to the lower part of each belt 556, and the paper P can be sent out in the paper feeding direction a by rotational driving of each belt 556.

  As shown in FIG. 4, a transport unit 57 is disposed in the vicinity of the sending unit 55 and on the downstream side in the paper feeding direction a. The conveyance unit 57 is provided in the middle of the insertion guide unit 571 into which the paper P fed from the lower part of the belt 556 can be inserted, and is conveyed downstream of the paper feeding direction a with the paper P interposed therebetween. Large and small transport rollers 572, 573, a motor (not shown) as a drive source for rotationally driving the transport rollers 572, 573, the arrival of the leading end of the paper P to the insertion guide portion 571, and the rear end of the paper P A paper detection unit 574 that is an optical or contact type sensor that detects the passage of the unit.

The insertion guide portion 571 is formed in a shape in which the end on the upstream side in the paper feeding direction a is wide open up and down, and the vertical width is narrowed toward the paper feeding direction a. The upstream end is connected to the conveyance path of the paper P toward the image forming apparatus main body 100a.
The large-diameter conveyance roller 572 and the small-diameter conveyance roller 573 are arranged so as to contact each other, and the insertion guide so that the paper P passing through the insertion guide portion 571 passes between the conveyance roller 572 and the small-diameter conveyance roller 573. The portion 571 is provided.
The large-diameter transport roller 572 uses a motor (not shown) as a drive source, and the motor is driven by the control unit 400. Since the small-diameter conveyance roller 573 is in contact with the large-diameter conveyance roller 572, a reverse rotation torque is transmitted to the large-diameter conveyance roller 572 so that the rotation is performed.

The paper detection unit 574 is arranged in the vicinity of the respective transport rollers 572 and 573 and upstream of the paper feeding direction a, detects the presence or absence of the paper P at the position of the paper detection unit 574, and the detection result Is input to the control unit 400 as needed. That is, when the detection state changes from a state where there is no paper P to a certain state, the control unit 400 recognizes that the leading end of the paper P has reached the position of the paper detection unit 574, and the state where the paper P is present When the detection state is changed to a state where there is no paper, it is recognized that the trailing edge of the paper P has passed the position of the paper detection unit 574.
The leading edge of the paper P indicates the downstream edge of the paper P in the paper feeding direction a, and the trailing edge of the paper P indicates the upstream edge of the paper P in the paper feeding direction a.

(4) Control Unit The control unit 400 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, and the like. The CPU 401 reads out a program corresponding to the processing content from the ROM 402 and develops it in the RAM 403. In cooperation with the developed program, each block of the image forming apparatus 100 (image reading device SC, automatic document feeder DF, image processing unit 30). The image forming apparatus main body 100a, the sheet feeding device 500, and the like) are centrally controlled. At this time, various data stored in the storage unit 410 are referred to. The storage unit 410 is configured by, for example, a nonvolatile semiconductor memory (so-called flash memory) or a hard disk drive.
The control unit 400 includes a communication unit 420 including a communication control card such as a LAN card (not shown), and is connected to an external network connected to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network). Various data can be transmitted to and received from a device (for example, a personal computer).

[Paper control method]
A method of controlling the sheet feeding operation by each sheet feeding unit 50 of the sheet feeding device 500 by the control unit 400 will be described.

In the paper feeding operation of the paper feeding unit 50, the upper paper P is floated by the floating air from the floating air blowing units 53 and 54, and is sucked to the lower part of each belt 556 and sent to the conveying unit 57 side. The sheet P that has floated is adsorbed to the lower part of the belt 556, but as shown in FIG. 7A, not only the uppermost sheet P but also one or more sheets below it float. Further, as shown in FIG. 7B, the sheet is pushed up by the floating air, and another sheet is brought into close contact with the lower side of the uppermost sheet P.
Therefore, the separation air blower 52 blows the separation air onto the sheet that has floated, so that the sheet P adsorbed on the lower portion of the belt 556 and the other sheets are separated as shown in FIG. Drop the paper by its own weight.

  Here, if the blown air amount is not sufficient at the start of the blowing of the floating air, the uppermost sheet P does not float to the lower part of each belt 556 and is adsorbed to the belt 556 as shown in FIG. Can not. Heavy paper such as thick paper (for example, paper having a basis weight of 300 g or more) is difficult to float, and the state as shown in FIG. 7D is likely to occur. It is necessary to make it larger than when feeding paper.

However, if the flying air is too strong after the paper has floated, the paper posture may become unstable, such as paper flapping.
Further, since the floating air continues to hit when the paper is separated, the separation efficiency by the separation air is lowered. In particular, when feeding soft paper with low density such as bulky paper, the floated paper is difficult to separate, so the uppermost paper P and one or more papers below it are attached to the transport unit 57 side. May cause multiple feeds.
Therefore, after the sheet floats, it is necessary to reduce the air flow rate of the floating air with respect to the air flow rate of the separation air blown to the front end of the paper.

Therefore, in the present embodiment, the amount of air blown is controlled by controlling the blowing air blowing direction by the floating air blowing units 53 and 54.
First, since a large air blowing amount is required to float the paper P at the start of paper feeding, as shown in FIG. 8A, the air blowing direction of the floating air by the floating air blowing portions 53 and 54 is changed to that of the paper P, respectively. By directing in the front end direction (downstream of the paper feeding direction a), the separation air and the floating air collide with each other. The collided air travels upward, and therefore has a strong levitation force for causing the paper P to float.
At this time, the air direction switching members 534 and 544 are controlled so that the air blowing ports 532 and 542 are opened to the separation air blowing portion 52 side by rotation as shown in FIG.

  Next, when the suction detection unit 557 detects the suction of the paper P, the control unit 400 determines that the uppermost paper P has floated. If the collided air continues to hit the paper after the paper P is lifted, the posture of the paper, such as paper flapping, may be disturbed. In addition, in order to separate the uppermost sheet P from the lower sheet, it is necessary to weaken the blowing air. Therefore, after the sheet P is lifted, as shown in FIG. 8B, the sheet P is rotated toward the rear end side of the sheet P from the direction in which the air blowing ports 532 and 542 open to the separation air blowing unit 52 side. By swinging the air blowing direction of the air blowing units 53 and 54 in the rear end direction of the paper P (upstream side in the paper feeding direction a), excessive floating force is suppressed and the air flow is stabilized.

In addition, since the ease of floating or separation differs depending on the type of paper as described above, it is possible to control the blowing direction of the floating air according to the type of paper.
For example, in the case of light paper such as bulky paper or thin paper, it is necessary to reduce the air volume of the floating air with respect to the separation air in order to ensure separation. In this case, as shown in FIG. 8C, the air blowing direction of the floating air blowing units 53 and 54 is directed to the rear end direction of the paper P (upstream side of the paper feeding direction a) from the start of paper feeding. . In the case of a light paper, even a weak floating air can sufficiently float, so there is no problem even if the blowing direction of the floating air is as described above from the start of paper feeding. At this time, the wind direction switching members 534 and 544 are controlled so as to be in the direction shown in FIG.

Next, the operation of the image forming apparatus 100 will be described using the flowchart of FIG.
First, when a print instruction is received, the control unit 400 acquires sheet information for a sheet designated by the user (step S901). The sheet information includes information about the basis weight and size of the sheet.

  Next, the control unit 400 determines whether the sheet is likely to float based on the sheet information (step S902). If it is determined that the sheet is likely to float (step S902: Yes), the process proceeds to step S911. If it is determined that the sheet is not likely to float (step S902: No), the process proceeds to step S903. Here, it is determined that the paper is likely to float when the paper has a basis weight of less than 300 g.

  In step S903, the control unit 400 controls the motors 537 and 547 to rotate the air direction switching members 534 and 544 so that the flying air is blown toward the leading edge of the sheet. That is, the wind direction switching members 534 and 544 are arranged in the direction as shown in FIG.

  Subsequently, the control unit 400 controls the separation air blowing unit 52 and the floating air blowing units 53 and 54 to start blowing the separation air and the floating air (step S904), and the suction detection unit 557 detects the floating of the sheet. It is determined whether or not it has been done (step S905). When the control unit 400 determines that the ascent is not detected (step S905: No), the process proceeds to step S906. When the control unit 400 determines that the ascent is detected (step S905: Yes), the process proceeds to step S908.

  In step S906, the control unit 400 determines whether or not a predetermined time has elapsed. If the control unit 400 determines that the predetermined time has not elapsed (step S906: No), the process proceeds to step S905, but determines that the predetermined time has elapsed. Then (step S906: Yes), the motors 537 and 547 are controlled to rotate the air direction switching members 534 and 544 so that the blowing direction of the flying air is further directed toward the leading edge of the sheet (step S907), and the process returns to step S905. .

In step S908, the control unit 400 controls the motors 537 and 547 to rotate the wind direction switching members 534 and 544, and swings the flying air toward the trailing edge of the sheet. That is, the wind direction switching members 534 and 544 are operated as shown in FIG.

  Subsequently, the control unit 400 determines whether or not it is the last page (step S909), and determines that it is the last page (step S909: Yes). (Step S909: No), the control unit 400 controls the motors 537 and 547 to rotate the air direction switching members 534 and 544 so that the flying air is blown toward the leading edge of the paper (Step S910), and the process proceeds to Step S905. And return.

  In step S911, the control unit 400 controls the motors 537 and 547 to rotate the air direction switching members 534 and 544 so that the flying air is blown toward the rear end of the sheet. That is, the wind direction switching members 534 and 544 are arranged in the direction as shown in FIG.

  Subsequently, the control unit 400 controls the separation air blowing unit 52 and the floating air blowing units 53 and 54 to start blowing the separation air and the floating air (step S912), and determines whether it is the last page. (Step S913) If it is determined that the page is the last page (Step S913: Yes), the control is terminated. If it is determined that the page is not the last page (Step S913: No), the process of Step S913 is repeated.

  As described above, by changing the blowing air blowing direction according to the paper type, adjustment is made so that the air volume suitable for the floating and separation of the paper is obtained.

  As described above, the image forming apparatus 100 according to the present embodiment includes the separation air blowing unit 52, the floating air blowing units 53 and 54, and the delivery unit 55 having the suction unit 56, and the floating air blowing unit. 53 and 54 are further provided with wind direction switching members 534 and 544 and shafts 535 and 545, gear pairs 536 and 546, and motors 537 and 547, respectively, capable of switching the blowing direction. The control unit 400 changes the blowing direction by the floating air blowing units 53 and 54 according to the basis weight, size, and floating state of the paper. Therefore, stable paper feeding can be performed by adjusting the amount by which the flying air and the separation air collide under conditions that make it difficult to fly, such as when the paper is heavy or large.

  Further, in the image forming apparatus 100 according to the present embodiment, when the suction detection unit 557 detects that the uppermost sheet P has floated, the air blowing direction by the floating air blowing units 53 and 54 is moved upstream in the paper feeding direction. And turn. Therefore, a stable airflow can be obtained without excessive air flow by flowing the flying air to the rear end side of the paper after the paper has floated.

  Further, in the image forming apparatus 100 according to the present embodiment, when the suction detection unit 557 does not detect that the uppermost sheet P has floated for a predetermined time, the blowing direction by the floating air blowing units 53 and 54 is set to the sheet feeding direction. Turn downstream. Therefore, until the sheet rises, the air is blown so that the flying air and the separation air collide with each other, so that a strong flying force can be obtained.

  Further, in the image forming apparatus 100 according to the present embodiment, the floating air blowing units 53 and 54 also function as a regulating member and can move in the left-right direction. Therefore, even if the size of the paper is changed, it is possible to move from the vicinity of the paper on which the paper is stacked to a position where air can be blown.

  In addition, the image forming apparatus 100 according to the present embodiment includes air direction switching members 534 and 544 for blowing air in a horizontal direction or a direction inclined slightly above the horizontal direction. Therefore, since the flying air is blown toward the sheet floating direction, the sheet can be efficiently lifted.

  In the above flowchart, two types of control are performed according to whether or not the sheet is likely to float, but the type of the sheet may be changed in the blowing direction for each sheet width. The correspondence relationship between the paper type and the angle of the wind direction switching members 534 and 544 with respect to the horizontal direction b may be preliminarily tabulated and stored in the storage unit 410 or set by the user according to the paper type. It is good also as what to do.

It is also possible to change the air blowing direction according to the paper width size.
For example, when the sheet width is large and the floating air blowing parts 53 and 54 are located at positions separated from each other in the left-right direction, the separation air and the floating air are less likely to collide with each other. In such a case, the air direction switching members 534 and 544 are directed more toward the center in the width direction of the paper, thereby making it easy to cause separation air and flying air to collide.
The correspondence relationship between the paper width and the angle of the wind direction switching members 534 and 544 with respect to the left-right direction b may be preliminarily tabulated and stored in the storage unit 410 or set by the user according to the paper width. It may be a thing.

[Other Embodiments]
As mentioned above, although concretely demonstrated based on embodiment which concerns on this invention, said embodiment is a suitable example of this invention, and is not limited to this.

  For example, in the above-described embodiment, the case where the paper feeding device is mounted on the electrophotographic image forming apparatus is illustrated, but the type of the image forming apparatus is not limited thereto. For example, the paper feeding device 500 can be applied to any type of image forming apparatus that forms an image on an ink jet type or other paper.

In the above embodiment, the sheet floating is detected by detecting the contact of the sheet with the detection body 557a. However, the present invention is not limited to this.
For example, when the sheet is adsorbed to the adsorbing unit 56, the opening 561a is blocked, and the suction pressure is changed. It is also possible to detect the floating of the paper by detecting this suction pressure.
In addition, a reflection type sensor may be provided on both the left and right sides of the paper stacking table 511, or the reflected light from the floating paper may be detected to detect the floating of the paper.

  In addition, the detailed configuration of each apparatus constituting the image forming apparatus and the detailed operation of each apparatus can be appropriately changed without departing from the gist of the present invention.

50 Paper Feeder 51 Paper Stacking Unit (Paper Stacking Unit)
52 Separation air blower 53, 54 Floating air blower 531, 541 Blower fan 532, 542 Blower port 533, 543 Nozzle 534, 544 Air direction switching member (wind direction switching unit)
535,545 shaft (wind direction switching part)
536,546 Gear pair (wind direction switching part)
537, 547 Motor (wind direction switching part)
55 Delivery unit 557 Adsorption detection unit (floating detection unit)
557a detector 557b sensor 56 suction unit 57 transport unit 100 image forming apparatus 100a image forming apparatus main body 400 control unit 500 paper feeding device

Claims (6)

A paper stacking unit for storing paper in a stacked state;
A separation air blower that blows air onto the paper from the leading edge in the paper feeding direction of the loaded paper;
A floating air blower that blows air from both sides of the paper edge perpendicular to the paper feeding direction of the loaded paper;
An adsorbing part that adsorbs the uppermost sheet that has floated;
A wind direction switching unit that changes a blowing direction of the floating air blowing unit in an arbitrary direction from a direction toward a leading end side in a paper feeding direction of stacked sheets to a direction toward a rear end side; and
A control unit that controls a change in the blowing direction of the floating air blowing unit by the wind direction switching unit according to at least one of the basis weight and size of the sheet and the floating state of the sheet. Paper feeder. Equipped with a floating detection unit that detects the floating of the loaded paper,
The controller is
When the floating detection unit detects the floating of the sheet, the blowing direction of the floating air blowing unit is changed to a direction toward the rear end side in the sheet feeding direction of the stacked sheets. The sheet feeding device according to 1. Equipped with a floating detection unit that detects the floating of the loaded paper,
The controller is
When the floating detection unit does not detect the floating of the paper within a predetermined period from the start of paper feeding, the blowing direction of the floating air blowing unit is changed to the direction toward the front end side of the stacked paper feeding direction. The sheet feeding device according to claim 1, wherein:   The sheet feeding device according to any one of claims 1 to 3, wherein the floating air blowing section is movable in a direction parallel to a surface of the stacked sheets and perpendicular to a sheet feeding direction.   5. The sheet feeding device according to claim 1, wherein the floating air blowing unit blows air obliquely upward with respect to a sheet surface. A sheet feeding device according to any one of claims 1 to 5,
An image forming apparatus comprising: an image forming unit that forms a toner image on a sheet.

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