Paper feeder and image forming apparatus

Abstract

To provide a paper feed device in which it is less likely that multiple sheets of paper are sent out in a stacked state, compared to a case of spraying gas on a paper bundle under only one fixed condition without changing conditions for spraying gas on the paper bundle.SOLUTION: There is provided a paper feed device, including: paper feed means for feeding a highest-level paper included in a paper bundle; spray means for spraying gas on a side of the paper bundle; and a processor that reduces an air volume of gas sprayed to the side when a certain predetermined condition is met. The processor reduces the air volume when an environment of a place where the paper feed device is installed satisfies a predetermined specific condition.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a paper feeder and an image forming apparatus. [Background technology]

[0002] Patent document 1 discloses a paper feeding device that includes a housing, a paper feed tray having a loading plate on which paper is loaded and that is attached to the inside and outside of the housing so that it can slide freely inside and outside, and a transport means that transports the paper loaded on the loading plate in a direction perpendicular to both the sliding direction of the paper feed tray and the loading direction of the paper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-653 A Summary of the Invention [Problem to be solved by the invention]

[0004] When sheets are fed out of a stack of sheets, gas may be blown onto the side of the stack of sheets to prevent the sheets below from sticking to the top sheet. Depending on the conditions under which the gas is blown, the lower sheet may be urged toward the uppermost sheet, and not only the uppermost sheet but also the lower sheets may be transported. The object of the present invention is to reduce the likelihood of multiple sheets of paper being sent out in an overlapping state, compared to when gas is blown onto a stack of paper under only one fixed condition without changing the conditions for blowing gas onto the stack of paper. [Means for solving the problem]

[0005] The invention described in claim 1 includes a paper feed means for feeding the topmost paper included in a paper stack, and a side portion of the paper stack. a leading edge side portion which is a side portion located at the leading edge in the paper feed direction by the paper feed means A blowing means for blowing gas onto the Tip sideThe gas is blown onto a guide surface that guides the gas toward the side, changing the direction in which the gas is directed, and then the gas is blown onto the guide surface that guides the gas toward the side. Tip side A blowing means for blowing on the side, When a predetermined condition is satisfied, the amount of gas blown onto the tip side portion by the blowing means is reduced, The paper feeder is configured so that the position of the guide surface relative to the stack of paper can be changed in the paper feed direction by the paper feed means. The invention described in claim 2 is a paper feeding device described in claim 1, in which at least a part of the guide surface is located downstream of the paper stack in the feed direction, and the position of the guide surface relative to the paper stack is changed by at least one of the paper stack and the guide surface moving downstream and upstream in the feed direction. The invention described in claim 3 is a paper feeding device described in claim 2, in which the guide surface is positioned above the paper stack and facing downward, and is configured to be able to take at least two states: a first state in which a part of the paper stack is located at the position facing the guide surface, and a second state in which the paper stack is not located at the position facing the guide surface. In the invention described in claim 4, the guide surface is formed so as to be convex upward, has a curvature, and has one end and the other end, and the gas flows along the guide surface and flows from the one end side to the other end side, and then the gas leaves the guide surface and flows into the Tip side Towards the side Tip side The paper feeder according to claim 3, wherein the air is sprayed onto the side. The invention described in claim 5 is a paper feeding device described in claim 1, further comprising a processor that changes the position of the guide surface relative to the paper stack, wherein the processor changes the position of the guide surface relative to the paper stack in the feed direction when the environment of the location where the paper feeding device is installed satisfies predetermined specific conditions. The invention described in claim 6 further comprises a paper feed means for feeding the topmost paper included in the paper stack, and a side portion of the paper stack. a leading edge side portion which is a side portion located at the leading edge in the paper feed direction by the paper feed means A blowing means for blowing gas onto the Tip sideThe gas is blown onto a guide surface that guides the gas toward the side, changing the direction in which the gas is directed, and then the gas is blown onto the guide surface that guides the gas toward the side. Tip side a blowing means for blowing on the side of the paper; and an image forming section for forming an image on the paper fed by the paper feeding means, When a predetermined condition is satisfied, the amount of gas blown onto the tip side portion by the blowing means is reduced, The image forming apparatus is configured so that the position of the guide surface relative to the stack of sheets can be changed in the sheet sending direction by the sheet sending means. Effect of the Invention

[0006] Claim 1、2 According to the invention, it is possible to reduce the likelihood of multiple sheets of paper being sent out in an overlapping state, compared to a case in which gas is blown onto a stack of paper under only one fixed condition without changing the conditions for blowing gas onto the stack of paper. Claim 3 According to this invention, the occurrence of double feeding is reduced compared to a configuration in which only one of a first state in which a part of the paper stack is located at the opposite position to the guide surface and a second state in which the paper stack is not located at the opposite position to the guide surface can be assumed. Claim 4 According to the invention, it is possible to generate a flow of gas that flows from obliquely above the stack of sheets toward the side of the stack of sheets. Claim 5 According to the invention, when the environment in which the paper feeder is installed satisfies a specific condition that is set in advance, the position of the guide surface with respect to the paper stack is changed. Claim 6 According to the invention, it is possible to reduce the likelihood of multiple sheets of paper being sent out in an overlapping state, compared to a case in which gas is blown onto a stack of paper under only one fixed condition without changing the conditions for blowing gas onto the stack of paper. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an image forming apparatus. [Diagram 2]1A to 1D are diagrams illustrating a paper feed section. [Diagram 3] 3 is a perspective view of the suction part as viewed from the direction of arrow III in FIG. 2(A). [Figure 4] 4 is a diagram of a paper stacking section and the like as viewed from the direction of arrow IV in FIG. 2(A). [Diagram 5] FIG. 2 is a diagram of the suction unit as viewed from the side. [Figure 6] FIG. [Figure 7] 7 is a view of the suction part as viewed from the direction of arrow VII in FIG. 2(B). [Figure 8] 8 is a cross-sectional view of the suction portion and the tip-side blowing mechanism taken along line VIII-VIII in FIG. 5. [Figure 9] 13(A) and 13(B) are diagrams showing other configuration examples of the recessed portion. [Figure 10] 13 is a diagram showing another example of the configuration of the paper feed section; FIG. [Figure 11] FIG. 2 is a diagram showing a configuration of a control unit. [Figure 12] FIG. 2 is a diagram showing the state of sheets included in a sheet stack. [Figure 13] 11A and 11B are diagrams illustrating a state of a stack of paper when air is blown onto the stack of paper. [Figure 14] FIG. 13 is a diagram illustrating a sprayed area. [Figure 15] FIG. 11 is a diagram illustrating another example of processing. [Figure 16] FIG. 11 is a diagram illustrating another example of processing. [Figure 17] 13A and 13B are diagrams showing other configuration examples of the guide surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus 1 according to an embodiment of the present invention. 1 is an intermediate transfer type image forming apparatus 1 called a tandem type. This image forming apparatus 1 is provided with an image forming section 1A that forms an image on paper P, which is an example of a recording material. In addition, a paper feeder 1B that sequentially feeds out paper P stacked in a paper stacking section 53 is provided.

[0009] Further, inside the image forming apparatus 1, an environment sensor S that acquires information about the environment inside the image forming apparatus 1 is provided. This environment sensor S acquires information about the temperature and humidity inside the image forming apparatus 1. The image forming section 1A, which is an example of an image forming means, is provided with a plurality of image forming units 111Y, 111M, 111C, and 111K that form toner images of respective color components by electrophotography.

[0010] The image forming section 1A is also provided with a primary transfer section 10 which transfers (primary transfers) the respective color component toner images formed by the image forming units 111Y, 111M, 111C, and 111K onto the intermediate transfer belt 15 in sequence. The image forming section 1A is also provided with a secondary transfer section 20 that transfers the superimposed toner images transferred onto the intermediate transfer belt 15 onto the paper P all at once (secondary transfer).

[0011] The image forming apparatus 1 is also provided with a fixing device 60 that fixes the toner image secondarily transferred onto the paper P onto the paper P. Further, there is provided a control unit 40 for controlling the operation of each device (each unit). Also, there is provided a UI (User Interface) 70, which is configured with a display panel or the like, and receives information from the user and displays the information to the user.

[0012] FIG. 11 is a diagram showing the configuration of the control unit 40. As shown in FIG. The control unit 40 is composed of a central processing unit (CPU) 103A, a read only memory (ROM) 103B, and a random access memory (RAM) 103C. ROM 103B stores a program executed by CPU 103A. CPU 103A, which is an example of a processor, reads out the program stored in ROM 103B and executes the program using RAM 103C as a working area.

[0013] Here, the program executed by CPU 103A may be provided to control unit 40 in a state where it is stored on a computer-readable recording medium such as a magnetic recording medium (magnetic tape, magnetic disk, etc.), an optical recording medium (optical disk, etc.), a magneto-optical recording medium, or a semiconductor memory. Furthermore, the programs executed by the CPU 103A may be downloaded to the control unit 40 using a communication means such as the Internet.

[0014] In this embodiment, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). In addition, the operations of the processor may not only be performed by one processor, but may be performed by multiple processors in physically separate locations working together. The order of the operations of the processor is not limited to the order described in this embodiment, and may be changed.

[0015] The image forming apparatus 1 will be further described with reference to FIG. Each of the image forming units 111Y, 111M, 111C, and 111K is provided with the following devices. First, a charger 12 for charging the photoconductor drum 11 is provided around the photoconductor drum 11 which rotates in the direction of arrow A. Also, an exposure device 13 for writing an electrostatic latent image on the photoconductor drum 11 is provided. Furthermore, a developer 14 for developing the electrostatic latent image on the photoconductor drum 11 with toner is provided.

[0016] Further, each of the image forming units 111Y, 111M, 111C, and 111K is provided with a primary transfer roll 16 that transfers the toner image of each color component formed on the photosensitive drum 11 onto the intermediate transfer belt 15 at the primary transfer section 10. Further, each of the image forming units 111Y, 111M, 111C, and 111K is provided with a drum cleaner 17 for removing residual toner and the like from the photosensitive drum 11.

[0017] The intermediate transfer belt 15 circulates in the direction of arrow B shown in FIG. 1 at a predetermined speed. The primary transfer section 10 includes a primary transfer roll 16 disposed opposite the photosensitive drum 11 with an intermediate transfer belt 15 interposed therebetween. In this embodiment, the toner images on the photoconductor drums 11 are electrostatically attracted to the intermediate transfer belt 15 in sequence, and superimposed toner images are formed on the intermediate transfer belt 15 .

[0018] The secondary transfer unit 20 includes a secondary transfer roll 22 disposed opposite the outer circumferential surface of the intermediate transfer belt 15 , and a backup roll 25 . The secondary transfer roll 22 is pressed against the backup roll 25 with the intermediate transfer belt 15 sandwiched therebetween. Furthermore, a voltage is applied between the secondary transfer roll 22 and the backup roll 25, and the toner image is secondarily transferred onto the paper P transported to the secondary transfer unit 20.

[0019] In this embodiment, image data is output to the image forming apparatus 1 from an image reading device (not shown), a personal computer (PC), or the like. Then, this image data is subjected to image processing by an image processing device (not shown) to generate image data for the four colors Y, M, C, and K. This image data is then output to an exposure device 13 provided for each of the colors Y, M, C, and K.

[0020] In the exposure device 13, an exposure beam Bm emitted from, for example, a semiconductor laser is irradiated onto the photoconductor drums 11 of the image forming units 111Y, 111M, 111C, and 111K in accordance with input image data. After the surface of each photosensitive drum 11 is charged by the charger 12, the surface is scanned and exposed by the exposure device 13 to form an electrostatic latent image.

[0021] Then, after a toner image is formed on the photosensitive drum 11 by the developing device 14, this toner image is transferred onto the intermediate transfer belt 15 in the primary transfer section 10 where each photosensitive drum 11 and the intermediate transfer belt 15 come into contact with each other. After the toner images are sequentially transferred onto the surface of the intermediate transfer belt 15, As a result of this movement, the toner image is transported to the secondary transfer unit 20 .

[0022] In the secondary transfer section 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. The paper P conveyed from the paper stacking section 53 is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. As a result, the unfixed toner images held on the intermediate transfer belt 15 are electrostatically transferred all at once onto the paper P in the secondary transfer section 20 . Thereafter, the paper P onto which the toner image has been transferred passes through a fixing device 60 and is discharged to a paper discharge section (not shown).

[0023] The paper feeder 1B is provided with a paper feed section 1C that feeds the uppermost paper P among the papers P stacked in the paper stacking section 53. In other words, the paper feeder 1B is provided with a paper feed section 1C that feeds the uppermost paper included in the paper stack 54. Furthermore, in this embodiment, a plurality of transport rolls 52 are provided for transporting the paper P sent out by the paper sending section 1C. Each of the conveying rolls 52 is composed of a drive roll 52A that rotates by receiving a driving force from a motor not shown, and a driven roll 52B that is arranged in contact with the drive roll 52A and rotates by receiving a driving force from the drive roll 52A.

[0024] In this embodiment, the paper P sent out by the paper sending section 1C is first transported by the transport roll 52 (hereinafter referred to as the "upstream transport roll 52E") that is located most upstream in the transport direction of the paper P among the multiple transport rolls 52. Then, the paper P is further transported by other transport rolls 52 located downstream of the most upstream transport roll 52E, and headed toward the secondary transfer unit 20 and the fixing device 60. In this embodiment, a conveyor belt 55 is further provided. The transport belt 55 is provided downstream of the secondary transfer roll 22 in the transport direction of the paper P, and transports the paper P on which the secondary transfer has been performed to a fixing device 60.

[0025] Figures 2(A) to (D) are diagrams for explaining the paper-sending section 1C. Figure 3 is a perspective view of a suction section 100 (described later) as viewed from the direction of arrow III in Figure 2(A). 2A, paper feed section 1C, which is an example of a paper feed means, is provided with suction section 100 that sucks paper P loaded on paper stacking section 53. Furthermore, a movement mechanism (not shown) that moves suction section 100 in the direction indicated by arrow 2A in the figure is provided. Here, this movement mechanism may be configured using a known mechanism such as a motor, gear, rack, pinion, belt drive, etc., and is not limited to a specific mechanism.

[0026] In this embodiment, the suction unit 100 is moved by the movement mechanism in a direction toward the most upstream transport roll 52E and a direction away from the most upstream transport roll 52E, as indicated by an arrow 2A. In addition, in this embodiment, the suction unit 100 is moved from above the paper stack 54 in the direction toward the most upstream transport roll 52E by the movement mechanism. Furthermore, in this embodiment, the suction unit 100, which has been moved toward the most upstream transport roll 52E side by the movement mechanism, is moved toward the paper stack 54 side and returns to above the paper stack 54.

[0027] As shown in FIG. 2(A), the suction unit 100 is provided with a rectangular parallelepiped device body 101 and a plurality of moving members 102 that are provided in a state of hanging down from the device body 101. A suction tube (not shown) is connected to the device body 101, and in this embodiment, the paper P is sucked by the device body 101, as described later. The moving member 102 is formed in a plate shape and is provided so as to be movable in the up and down direction.

[0028] As shown in FIG. 3, in this embodiment, the movable members 102 include a first tip side movable member 102A, a second tip side movable member 102B, a first rear end side movable member 102C, a second rear end side movable member 102D, a first right side movable member 102E, a second right side movable member 102F, a first left side movable member 102G, and a second left side movable member 102H.

[0029] In this embodiment, these eight moving members 102 separate a rectangular parallelepiped reduced pressure space 105 located below the device body 101 from an atmospheric pressure space 106 located around this reduced pressure space 105. In this embodiment, a rectangular parallelepiped space surrounded by eight moving members 102 becomes the reduced pressure space 105. Moreover, the space located outside this reduced pressure space 105 becomes an atmospheric pressure space 106 that is at atmospheric pressure.

[0030] A plurality of holes 101Y are formed in the lower surface 101X of the device body 101, and air is sucked through these holes 101Y from within the reduced pressure space 105. As a result, the pressure within the reduced pressure space 105 becomes lower than atmospheric pressure. When the air in the reduced pressure space 105 is sucked in and the pressure in the reduced pressure space 105 decreases, as shown in Figures 2(A) and (B), the paper P located below the reduced pressure space 105 is sucked in, and the paper P moves toward the underside 101X of the device body 101 (see Figure 2(B)).

[0031] Then, the sheet P adheres to the lower surface 101X, which is an example of an adsorption portion. In other words, in this embodiment, the sheet P is adsorbed to the lower surface 101X. More specifically, in this embodiment, the sheet P is adsorbed to the lower surface 101X from below. Here, the lower surface 101X as an example of the suction portion is a flat surface, and in this embodiment, the suction portion is a planar suction portion, and the paper sheet P is suctioned to this planar suction portion. In other words, in this embodiment, the paper sheet P is suctioned to the suction surface.

[0032] In this embodiment, when paper P is adsorbed to the lower surface 101X of the device main body 101, the eight movable members 102 shown in Figure 3 move upward from the state shown in Figure 2(A), and the eight movable members 102 become the state shown in Figure 2(B). 3, the eight moving members 102 are pressed from below by the paper P located below and move upward. Then, when the eight moving members 102 move upward, the paper P is attracted to the lower surface 101X of the device body 101.

[0033] In addition, in this embodiment, when the paper sheet P is adsorbed to the lower surface 101X, air is blown onto the edge 2G of the paper sheet P adsorbed to the lower surface 101X from above the lower surface 101X, as shown by the arrow 2F in Figure 2 (B). In addition, in this embodiment, air is blown onto the edge 2G of the paper sheet P that is adsorbed to the lower surface 101X from above the edge 2G.

[0034] More specifically, in this embodiment, the edge 2G shown in Figure 2(B) is the edge 2G located at the leading edge of the paper P when the paper P is transported (hereinafter referred to as the "leading edge 2G"), and in this embodiment, air is blown from above onto this leading edge 2G. In this embodiment, the case where air is blown against the leading edge 2G is described as an example, but air may be blown from above against an edge other than the leading edge 2G.

[0035] Thereafter, in this embodiment, as shown in FIG. 2(C), the suction section 100 moves toward the most upstream transport roll 52E, and the paper P adsorbed to the lower surface 101X of the device body 101 is supplied to this most upstream transport roll 52E. As a result, the transport of the paper P by the most upstream transport roll 52E starts.

[0036] In addition, in this embodiment, the suction unit 100 moves in a direction intersecting the vertical direction toward the most upstream transport roll 52E. As a result, the paper sheet P adhering to the lower surface 101X of the apparatus body 101 is supplied to the most upstream transport roll 52E, and transport of the paper sheet P by the most upstream transport roll 52E begins.

[0037] In other words, the uppermost sheet P included in the sheet stack 54 is sent toward the most upstream transport roll 52E, and transport of the sheet P by the most upstream transport roll 52E begins. Thereafter, in this embodiment, as shown in FIG. 2(D), the suction unit 100 returns to the side of the paper stack 54, and the suction unit 100 is again positioned above the paper stack 54.

[0038] Fig. 4 is a diagram of the paper stacking unit 53 and the like as viewed from the direction of arrow IV in Fig. 2(A). Additionally, Fig. 4 is a diagram of the paper stacking unit 53 and the like as viewed from above. 4, in this embodiment, a paper stack 54 in which multiple sheets of paper P are arranged in the thickness direction of the paper P is placed on the paper stacking section 53. The paper stack 54 and each sheet of paper P included in the paper stack 54 have a rectangular outer edge 104.

[0039] This rectangular outer periphery 104 is made up of a front outer periphery 104A, a rear outer periphery 104B, a first side outer periphery 104C, and a second side outer periphery 104D. The leading edge 104A is the outer edge 104 located on the most downstream side in the transport direction of the paper P. The leading edge 104A extends in a direction intersecting (orthogonal to) the transport direction of the paper P. The rear outer peripheral edge 104B is the outer peripheral edge 104 located most upstream in the transport direction of the paper P. This rear outer peripheral edge 104B also extends in a direction intersecting (orthogonal to) the transport direction of the paper P.

[0040] The first side outer periphery 104C is an outer periphery 104 that connects one end of the leading outer periphery 104A and one end of the trailing outer periphery 104B. The first side outer periphery 104C extends in the transport direction of the paper P. The second side outer peripheral edge 104D is an outer peripheral edge 104 that connects the other end of the leading outer peripheral edge 104A and the other end of the trailing outer peripheral edge 104B. This second side outer peripheral edge 104D also extends in the transport direction of the paper P.

[0041] Here, when the paper P is sucked, the device body 101 of the suction unit 100 is positioned inside the outer circumferential edge 104 of the paper stack 54, as indicated by reference symbol 4A in FIG. When the paper P is supplied to the most upstream transport roll 52E, the suction unit 100 moves toward the most upstream transport roll 52E as shown by an arrow 2B. Furthermore, in this embodiment, as shown in FIG. 4, a plurality of openings 4X are provided on the sides of the paper stack 54, and in this embodiment, air is sent from these openings 4X toward the paper stack 54, and air is also blown from the sides of the paper stack 54.

[0042] In this embodiment, a side blowing mechanism 400 as an example of a blowing means for blowing air onto the side of the paper stack 54 is provided on the side of the paper stack 54. The side blowing mechanism 400 includes an air supply source (not shown) such as a fan. The side blowing mechanism 400 also has an opening 4X, and blows air, which is an example of gas, from the opening 4X to a side of the paper stack 54 that faces a direction perpendicular to the feed direction of the paper P (hereinafter, referred to as the "orthogonal side 401").

[0043] Furthermore, in this embodiment, each of the driving roll 52A and the driven roll 52B provided on the most upstream transport roll 52E includes a rotating shaft 52X and a plurality of cylindrical members 52Y attached around the rotating shaft 52X. In this embodiment, when the suction section 100 moves toward the most upstream transport roll 52E, the suction section 100 enters between the two cylindrical members 52Y, so that no interference occurs between the suction section 100 and the most upstream transport roll 52E.

[0044] Referring again to FIG. 3, the configuration of the suction unit 100 will be further described. As described above, the suction unit 100 is provided with the device body 101. The device body 101 is provided with an air guide member 120 that guides air. The air guide member 120 is provided with an uneven portion 121 for imparting a wavy shape to the leading edge portion 2G of the paper P (see FIG. 2(B)).

[0045] The uneven portion 121 is arranged so as to extend in a direction perpendicular to the conveyance direction of the paper P. In addition, the uneven portion 121 is arranged so as to extend along the leading edge portion 2G of the paper P. There are. In this embodiment, when the paper P is attracted to the lower surface 101X of the device body 101, the leading edge 2G of the paper P is pressed against the uneven portion 121, and a wavy shape is imparted to the leading edge 2G.

[0046] Furthermore, the air guide member 120 is provided with a suction opening 122 on the lower surface 101X side of the uneven portion 121 for further suctioning the paper P adhering to the lower surface 101X. Furthermore, the air guide member 120 is provided with an air guide portion 123 that guides the air blown against the leading edge portion 2G.

[0047] In this embodiment, as described later, an air supply source such as a fan is provided below the lower surface 101X, which is the suction portion, and in this embodiment, air is once supplied from below the lower surface 101X toward above the lower surface 101X. In this embodiment, the air supplied in the upward direction is guided by the air guide portion 123, and the air flows downward.

[0048] In this embodiment, the uneven portion 121 and the air guide portion 123 are provided in one air guide member 120. In addition, in this embodiment, the air guide portion 123 is provided in the air guide member 120, which is the member in which the uneven portion 121 is provided. Additionally, in this embodiment, the uneven portion 121 and the air guide portion 123 are provided on the air guide member 120 which is a common member.

[0049] The air guide portion 123 is formed with a recess 124 that protrudes upward. More specifically, a recess 124 that protrudes upward is formed on the lower surface 123A of the air guide portion 123. In this embodiment, the inner surface of the recess 124 serves as a guide surface 129 that guides the air blown onto the paper stack 54. The recess 124 is formed in a groove shape. Furthermore, the recess 124 is provided along the direction in which the leading edge portion 2G of the paper sheet P extends, as shown in FIG.

[0050] More specifically, in this embodiment, a rectangular opening 125 is formed on the lower surface 123A (see FIG. 3) of the air guide portion 123, as shown in FIG. 4, and a recess 124 that protrudes upward is provided above this opening 125 (vertically upward), as shown in FIG. 3. 4, in this embodiment, an opening edge 126 exists around the periphery of the opening 125, surrounding the opening 125. The opening edge 126 is formed in a rectangular shape.

[0051] As shown in FIG. 4, the opening edge 126 is composed of a paper-side opening edge 126A, an opposite opening edge 126B, and two connecting opening edges 126C. The paper-side opening edge 126A is disposed so as to follow the leading edge 2G of the paper P. The opposite opening edge 126B is located on the opposite side to the leading edge 2G of the paper P, with the paper-side opening edge 126A in between. This opposite opening edge 126B is also disposed along the leading edge 2G of the paper P.

[0052] One of the two connecting opening edges 126C connects one end of the paper-side opening edge 126A to one end of the opposite opening edge 126B. The other connecting opening edge 126C connects the other end of the paper-side opening edge 126A to the other end of the opposite opening edge 126B.

[0053] FIG. 5 is a diagram of the suction unit 100 as viewed from the side thereof. In this embodiment, as shown in FIG. 5, a tip side blowing mechanism 500 is provided as another example of the blowing means. The leading edge blowing mechanism 500 blows air, which is an example of a gas, onto one of the sides of the paper-sheet stack 54 that is located at the leading edge in the conveyance direction of the paper-sheets P (hereinafter, referred to as "leading edge side 510"). In other words, the leading edge blowing mechanism 500 blows air against a leading edge side portion 510 of the side portion of the paper-sheet stack 54 that is located downstream in the direction in which the paper-sheets P are sent out by the paper-sheet sending section 1C (see FIG. 1).

[0054] The distal end blowing mechanism 500 is provided with an air supply unit 150 that supplies air to be blown against the distal end side portion 510 . The air supply unit 150 is provided with an air supply source 151 such as a fan, and a pipe 152 that guides the air sent out by the air supply source 151 obliquely upward. The air supply source 151 and the pipe 152 are located below the lower surface 101X of the device body 101.

[0055] At the tip of the tube 152, an exhaust port 152A is provided for exhausting air toward the recess 124 provided in the air guide member 120. The pipe 152 is also provided with a first inner wall surface 152C and a second inner wall surface 152D that are arranged opposite each other. A third inner wall surface 152E and a fourth inner wall surface (not shown) that connect the first inner wall surface 152C and the second inner wall surface 152D are also provided. In this embodiment, the first inner wall surface 152C is located closer to the paper P than the second inner wall surface 152D.

[0056] In this embodiment, as shown by arrow 5A, air from below the lower surface 101X of the device body 101 flows upward above the lower surface 101X, and then flows downward, and is blown toward the tip side portion 510 from above the lower surface 101X. In addition, in this embodiment, air from below the extended surface 5X of the lower surface 101X flows upward from the extended surface 5X, and then flows downward from the extended surface 5X and is blown against the tip side portion 510. In other words, the air flows downward from the extension surface 5X, and is blown against the tip edge 2G (see FIG. 4).

[0057] In this embodiment, the air is guided upward by the pipe 152 and then flows downward. Then, in this embodiment, the downward air is blown against the leading edge side portion 510 of the stack of paper-sheets 54. In addition, in this embodiment, the lower surface 123A of the air guide member 120 is used to direct air coming from below the lower surface 101X of the device body 101 downward. Then, the air directed downward is blown onto the upper portion of the tip side portion 510.

[0058] In this embodiment, the discharge port 152A is provided below a contact portion 52S between the driving roll 52A and the driven roll 52B provided on the most upstream transport roll 52E. Additionally, in this embodiment, the air that passes through the tube 152 is discharged from the exhaust outlet 152A located at the tip of the tube 152, which is located below the contact point 52S between the driving roll 52A and the driven roll 52B.

[0059] In addition, in this embodiment, the pipe 152 that guides the air flowing upward is configured not to cross the transport path R100 of the paper P. In addition, in this embodiment, the discharge port 152A of the pipe 152 is located below the transport path R100 of the paper P.

[0060] As a result, in this embodiment, only air crosses the transport path R100 of the paper P. In addition, in this embodiment, the pipe 152 does not cross the transport path R100 of the paper P, and only the air blown to the leading edge portion 2G crosses the transport path R100 of the paper. In this embodiment, the air that has crossed the transport path R100 heads toward the recess 124. The air is guided by the guide surface 129 provided in the recess 124, and the guided air is blown against the tip side portion 510.

[0061] Here, in this embodiment, when air is blown from above onto tip side portion 510, the air is sent diagonally downward as shown by arrow 5H, and the air sent diagonally downward is blown onto tip side portion 510. More specifically, the air sent diagonally downward is blown onto an upper portion of tip side portion 510. More specifically, in this embodiment, air is sent obliquely downward from above the tip side portion 510 and away from the tip side portion 510, and this air is blown against the tip side portion 510.

[0062] More specifically, in this embodiment, the leading edge portion 2G of the topmost sheet of paper P is clamped, and air is sent diagonally downward toward the leading edge side portion 510 from the side opposite to the side where the lower surface 101X is provided and from above the lower surface 101X, and the air is blown toward the upper portion of the leading edge side portion 510. In this way, when air is sent diagonally downward, as shown by arrow 5H, air is more likely to enter between the sheets of paper P than when air is sent straight downward. In this case, the second and subsequent sheets of paper P (hereinafter referred to as "lower sheets of paper P") adhering to the topmost sheet of paper P adsorbed to the lower surface 101X are more likely to detach from the topmost sheet of paper P.

[0063] In this embodiment, when transporting the paper P stacked in the paper stacking section 53, first, as shown in Figures 2(A) and (B), the topmost paper P among the stacked papers P is adsorbed to the suction section 100, and one sheet of paper P is removed. In addition, the uppermost sheet P of the paper stack 54 is sucked by the suction section 100, and one sheet P is taken out.

[0064] Then, in this embodiment, as shown in FIG. 2(C), the suction section 100 with the paper P adsorbed thereto moves toward the most upstream transport roll 52E, and the paper P adsorbed to the suction section 100 is sent to the most upstream transport roll 52E. In this embodiment, when the sheet P is taken out (when the sheet P is attracted by the suction unit 100), the suction unit 100 does not move up and down. However, the present invention is not limited to this. When removing the paper P, the suction unit 100 may be lowered, and when the paper P adheres to the suction unit 100, the suction unit 100 may be raised.

[0065] Here, for example, when the adhesive force between the sheets P is large, the lower sheets P may adhere to the uppermost sheet P adsorbed to the suction unit 100. In this case, multiple sheets P are supplied to the most upstream transport roll 52E, causing so-called double feeding. In this embodiment, in order to prevent the occurrence of double feeding, as described above, air is blown from above onto the leading edge side portion 510. This makes it easier for the lower sheets P adhering to the uppermost sheet P to separate from the uppermost sheet P.

[0066] Here, in this embodiment, when the suction unit 100 moves toward the most upstream transport roll 52E, the leading end side blowing mechanism 500 blows air onto the leading end side portion 510. In addition, in this embodiment, the tip side blowing mechanism 500 is configured to constantly blow air, and the tip side blowing mechanism 500 also blows air when the suction section 100 is moved. However, the present invention is not limited to this, and when the suction unit 100 moves toward the most upstream transport roll 52E, the air blowing may be stopped or the amount of air blowing may be reduced.

[0067] To explain further, in this embodiment, as shown in FIG. 5, a paper-facing surface 700 that faces the paper P is provided downstream in one direction from a lower surface 101X, which is an example of a suction portion. More specifically, in this embodiment, the paper P adsorbed to the lower surface 101X is transported in one direction indicated by the arrow 5T in FIG. 5, and in this one direction, a paper-facing surface 700 facing downward is provided downstream of the lower surface 101X.

[0068] In this embodiment, the paper P comes into contact with a portion of this paper-facing surface 700 that faces downward. More specifically, in this embodiment, the paper-facing surface 700 is provided with the uneven portion 121 and the recessed portion 124, and the paper P comes into contact with the portion of the paper-facing surface 700 where the uneven portion 121 is provided (the portion where the uneven surface is provided). In this embodiment, a portion of the paper-facing surface 700 facing downward faces the paper P adsorbed to the lower surface 101X. More specifically, the portion of the paper-facing surface 700 where the uneven portion 121 is provided (the portion where the uneven surface is provided) faces the paper P.

[0069] Furthermore, in this embodiment, an air supply unit 150 is provided below the lower surface 101X, and this air supply unit 150 blows air obliquely upward. Furthermore, in this embodiment, the paper-facing surface 700 and an extension of the direction in which the air is blown by the air supply unit 150 intersect with each other. Here, intersecting the paper-facing surface 700 with the extension of the air blowing direction by the air supply unit 150 refers to a state in which the paper-facing surface 700 intersects with an extension of the central axis 152X of the tube 152, which extends along the axial direction of the tube 152.

[0070] Furthermore, in this embodiment, as shown in Figure 7 (a view of the suction section 100 from the direction of arrow VII in Figure 2 (B)), when the uneven portion (uneven surface) 121 is viewed from the downstream side in the feed direction of the paper P, the unevenness is provided symmetrically on the left and right. In addition, if we assume an axis of symmetry PC that passes through the center of the paper P in the width direction and extends along the vertical direction, in this embodiment, the uneven portion (uneven surface) 121 is formed in a linearly symmetric relationship with respect to this axis of symmetry PC.

[0071] The air guide member 120 will now be further described with reference to FIG. As shown in FIG. 5, the air guide member 120 is provided with suction openings 122 on the lower surface 101X side of the uneven portion 121 for further sucking the paper P after the paper P adheres to the lower surface 101X. In this embodiment, when the sheet P is attracted to the lower surface 101X, the suction opening 122 starts suctioning the sheet P.

[0072] In this embodiment, as shown in Fig. 5, a connection path 250 is provided that connects the suction opening 122 and the inside of the device body 101, and the inside of this connection path 250 is depressurized. Note that, as shown in Fig. 3, this connection path 250 is formed so that its width (width in the direction in which the tip edge portion 2G extends) gradually increases downward. In this embodiment, until the sheet P adheres to the lower surface 101X, a gap is formed between the sheet P and the suction opening 122, and the sheet P is not sucked by the suction opening 122.

[0073] When the sheet P is attracted to the lower surface 101X, the gap between the sheet P and the suction opening 122 disappears, and the sheet P is attracted by the suction opening 122. When the paper sheet P is sucked by the suction opening 122, the leading edge 2G of the paper sheet P is urged against the uneven portion 121, and the leading edge 2G is pressed against the uneven portion 121. This gives the leading edge 2G an uneven shape. In other words, a wavy shape (described later) is given to the leading edge 2G.

[0074] FIG. 6 is a diagram illustrating the recess 124. As shown in FIG. In this embodiment, as described above, the concave portion 124 that is convex toward the upper side is formed in the air guide portion 123. As described above, this concave portion 124 is formed in a groove shape and is disposed along the direction in which the leading edge portion 2G (see FIG. 4) of the paper P extends. In this embodiment, the inner surface 124A of the recess 124 functions as a guide surface 129. The guide surface 129 guides the air, and the guided air is blown against the tip side portion 510.

[0075] The guide surface 129 constitutes a part of the tip side spray mechanism 500 . The distal end side blowing mechanism 500 blows air against this guide surface 129 to change the direction of the air, and then blows the air against the distal end side portion 510. The guide surface 129 is disposed at an incline with respect to the direction of air flow that flows in one direction. More specifically, the direction indicated by the reference symbol 6E is the air flow direction, and the guide surface 129 is disposed at an incline (intersect) with respect to this air flow direction.

[0076] The guide surface 129 is formed so as to be convex upward and has a curvature, so that its cross-sectional shape describes a circular arc. Further, the guide surface 129 has one end 129 A and the other end 129 B. Further, the guide surface 129 is disposed above the stack of paper-sheets 54 and faces downward.

[0077] In the cross section in a plane perpendicular to the direction in which the tip edge portion 2G (see FIG. 4) extends, in this embodiment, the guide surface 129 is formed so as to be convex toward the upward side and has a curvature, and further, the cross-sectional shape is formed so as to describe a circular arc. Furthermore, in this cross section, the other end 129B of the guide surface 129 is located closer to the tip side portion 510, and one end 129A is located farther from the tip side portion 510 than the other end 129B. In this embodiment, the cross-sectional shape of the guide surface 129 is the same as the shape of the line segments that make up an ellipse, as shown in FIG. 6, but is not limited thereto and may be the same as the shape of the line segments that make up a perfect circle, or may be V-shaped, as described later.

[0078] The guide surface 129 is provided with an inclined surface 142 that slopes downward as it approaches the side closer to the tip side portion 510 from the side farther from the tip side portion 510 . In this embodiment, the downward air is guided by the inclined surface 142, and the downward air is blown against the tip side portion 510.

[0079] Furthermore, in this embodiment, a guide portion 143 is provided on the guide surface 129 as shown in FIG. The guide portion 143 is located on the opposite side of the inclined surface 142 to the side on which the tip side portion 510 is located.

[0080] The guide portion 143 guides the air that flows upward from the lower surface 101X of the device body 101 toward the inclined surface 142. In addition, the guide portion 143 guides the air that is sent from below toward the inclined surface 142. Guide portion 143 is inclined so as to approach inclined surface 142 as it extends upward, and guide portion 143 utilizes this inclination given to itself to guide air from below toward inclined surface 142.

[0081] In this embodiment, when an imaginary plane passing through the second inner wall surface 152D of the pipe 152 (hereinafter referred to as a "first imaginary plane 6X") is assumed, this first imaginary plane 6X passes through the opposite opening edge 126B. However, without being limited to this, the second inner wall surface 152D may be provided so that this first imaginary surface 6X passes between the opposite opening edge 126B and the bottom 124S of the guide surface 129 (the bottommost part of the guide surface 129 formed in a concave shape). By having the first imaginary plane 6X pass through the opposite opening edge 126B or between the opposite opening edge 126B and the bottom 124S, the amount of air flowing toward areas other than the recess 124 can be reduced compared to when the first imaginary plane 6X passes through, for example, the location indicated by the symbol 6Z.

[0082] Furthermore, in this embodiment, when a virtual plane passing through first inner wall surface 152C of pipe 152 (hereinafter referred to as “second virtual plane 6Y”) is assumed, this second virtual plane 6Y passes through bottom portion 124S of guide surface 129. However, the present invention is not limited to this, and the first inner wall surface 152C may be provided such that the second imaginary surface 6Y passes between the bottom portion 124S and the opposite opening edge 126B and on the bottom portion 124S side of the first imaginary surface 6X.

[0083] In this embodiment, when air is blown toward the tip side portion 510, the air flows along the guide surface 129, as shown by the symbol 6G in FIG. 6, and also flows from one end 129A toward the other end 129B. The air then leaves the guide surface 129 and travels towards the tip side 510 where it is blown against the tip side 510 .

[0084] In this embodiment, air is blown onto the tip side portion 510 from above the tip side portion 510, as shown by arrow 7A in FIG. 7, and the air is blown onto the portion of the tip side portion 510 that has a wavy shape. More specifically, in this embodiment, the leading edge portion 2G of the paper sheet P is pressed against the uneven portion 121, whereby the leading edge portion 2G of the paper sheet P is given a wavy shape. In this embodiment, air is blown from above onto the portion to which the corrugated shape is to be imparted.

[0085] This makes it easier for air to get in between the topmost sheet P adsorbed to the suction section 100 and the sheets P underneath. More specifically, air is likely to get in between the uppermost sheet P and the lower sheet P through the gap 7X that occurs between the uppermost sheet P and the lower sheet P. In this case, the lower sheet P becomes easier to separate from the uppermost sheet P.

[0086] Here, a "wavy shape" refers to a shape in which one convex portion protruding from one side of the paper P to the other side and toward the thickness direction of the paper P and another convex portion protruding from the other side of the paper P to one side and toward the thickness direction of the paper P are arranged alternately in the direction in which the leading edge portion 2G extends. Here, the number of the first convex portion and the other convex portion is not particularly limited, and even if one first convex portion and one other convex portion are provided and this one convex portion and this other convex portion are adjacent to each other, it can be said that a wavy shape is imparted.

[0087] FIG. 8 is a cross-sectional view of the suction part 100 and the tip side blowing mechanism 500 taken along the line VIII-VIII in FIG. In this embodiment, the width L1 of the recess 124 formed in the air guide portion 123 and the width L2 of the outlet 152A provided at the tip of the tube 152 are equal to each other. Additionally, when comparing the width in the direction in which the tip edge portion 2G (see Figure 4) extends, the width L1 of the recess 124 formed in the air guide portion 123 and the width L2 of the exhaust port 152A provided at the tip of the tube 152 are equal.

[0088] In this embodiment, the case has been described in which the width L1 of the recess 124 formed in the air guiding portion 123 is equal to the width L2 of the exhaust port 152A provided at the tip of the tube 152. However, the width L1 of the recess 124 formed in the air guiding portion 123 may be larger than the width L2 of the exhaust port 152A provided at the tip of the tube 152. Here, when width L1 of recess 124 formed in air guiding portion 123 is greater than or equal to width L2 of exhaust outlet 152A provided at the tip of tube 152, more air is directed toward tip edge 2G and more air is blown toward tip edge 2G than when width L1 of recess 124 formed in air guiding portion 123 is smaller than width L2 of exhaust outlet 152A provided at the tip of tube 152.

[0089] In this embodiment, the first inner wall surface 152C is provided with three ribs RB extending along the air flow direction. Of the three ribs RB, the ribs RB located at both ends approach the center of the recess 124 in the width direction as they move toward the downstream side in the air flow direction. As a result, in this embodiment, more air is directed toward the recesses 124 than in a case where the ribs RB are not provided.

[0090] 9(A) and (B) are diagrams showing other configuration examples of the recess 124. In FIG. In the above, a curvature is provided to the guide surface 129. However, this is not limiting, and the guide surface 129 may be V-shaped as shown in Fig. 9(A). 9(A), the guide surface 129 is provided with an inclined surface 142 that slopes downward toward the tip side portion 510, as described above. Here, the inclined surface 142 is not given a curvature and is flat.

[0091] Also, in this configuration example, as in the above, a guide portion 143 is provided on the opposite side of the inclined surface 142 from the side on which the tip side portion 510 is located, to guide the air toward the inclined surface 142. The guide portion 143 is formed so as to rise toward the tip side portion 510. Furthermore, the guide portion 143 is not given a curvature, and is formed of a flat surface.

[0092] 9(B), an opposing member 180 is provided at a position opposing the guide surface 129. This opposing member 180 is disposed along the direction in which the tip edge portion 2G (see FIG. 4) extends. The opposing member 180 is fixed to the location indicated by the reference symbol 4Z in Fig. 4. In addition, the opposing member 180 is fixed to the portions of the air guide portion 123 that are located on both sides of the recessed portion 124.

[0093] 9B, the opposing member 180 is disposed with a gap between it and the guide surface 129, and is disposed at a position opposing the guide surface 129. As shown in FIG. Further, the opposing member 180 is located between the paper-side opening edge 126A and the opposite opening edge 126B.

[0094] In this configuration example, the space between the opposite opening edge 126B and the opposing member 180 is an air inlet 9EN. The space between the paper-side opening edge 126A and the opposing member 180 is an air outlet 9EX. In this configuration example, air supplied by the air supply unit 150 (not shown in FIG. 9(B)) passes through the inlet portion 9EN and heads toward the guide surface 129. The air is then guided by the guide surface 129 toward the outlet portion 9EX. The air leaving the outlet portion 9EX is then blown toward the tip side portion 510.

[0095] Next, control of the volume of air blown by the tip-end side blowing mechanism 500 will be described. In this embodiment, the CPU 103A (see FIG. 11), which is an example of a processor, reduces the amount of air blown to the tip side portion 510 when a specific predetermined condition is satisfied. Specifically, when a predetermined specific condition is satisfied, CPU 103A reduces the output of the air supply source provided in tip side blowing mechanism 500, and reduces the amount of air blown against tip side portion 510.

[0096] More specifically, when the environment where the paper feeding device 1B (see FIG. 1) is installed satisfies predetermined specific conditions, and when the paper P contained in the paper stack 54 satisfies specific conditions, the CPU 103A reduces the volume of air blown toward the leading edge side portion 510.

[0097] More specifically, when the humidity at the location where the paper feeding device 1B (see FIG. 1) is installed is lower than a predetermined threshold, and when a value determined by information regarding the thickness of the paper P contained in the paper stack 54 is lower than a predetermined threshold, the CPU 103A reduces the amount of gas blown toward the leading edge side portion 510. More specifically, the CPU 103A reduces the volume of air blown toward the leading edge side portion 510, for example, when the humidity at the location where the paper feeding device 1B is installed is less than 50% and when the basis weight of the paper P is less than 176 gsm (grams per square meter).

[0098] In the present embodiment, the case where basis weight is acquired as information relating to the thickness of the sheets P included in the sheet stack 54 has been described as an example. However, without being limited to this, a specific numerical value that represents the thickness of the paper P itself may be acquired as information regarding the thickness of the paper P included in the paper stack 54. In addition, information such as the model number or product number of the paper P may be obtained, and the thickness of the paper P may be ascertained based on this model number or product number.

[0099] In this embodiment, the humidity of the location where the sheet feeding device 1B is installed is acquired by an environmental sensor S (see FIG. 1). CPU 103A obtains the output from the environmental sensor S to obtain information about the humidity of the location where the sheet feeding device 1B is installed. In the present embodiment, information about the paper sheets P included in the paper stack 54 is input to the image forming apparatus 1 by the user operating the UI 70. The CPU 103A obtains the information about the paper sheets P by obtaining the information about the paper sheets P input via the UI 70.

[0100] The CPU 103A determines whether or not a predetermined condition is satisfied based on information from the environmental sensor S and the UI 70. Then, CPU 103A reduces the amount of air blown to tip side portion 510 when a predetermined condition is satisfied. Specifically, as described above, the CPU 103A reduces the volume of air blown toward the leading edge side portion 510 when, for example, the humidity at the location where the paper feeder 1B is installed is less than 50% and the basis weight of the paper P is less than 176 gsm.

[0101] When a predetermined condition is satisfied, by reducing the amount of air blown onto the leading end side portion 510, double feeding is less likely to occur. Specifically, by reducing the amount of air blown onto the leading edge side portion 510, the lower paper P is less likely to be forced toward the uppermost paper P, and the lower paper P is less likely to be sent out together with the uppermost paper P.

[0102] Here, it is assumed that the thickness of the paper P is small and that the humidity at the location where the paper feeder 1B is installed is lower than a predetermined threshold value. In this case, as shown in FIG. 12 (a diagram showing the state of sheets P contained in sheet bundle 54), the sheets P contained in sheet bundle 54 are likely to curl.

[0103] In this case, when air is blown onto the leading edge side portion 510, air tends to get in between, for example, the second sheet of paper P from the top and the third sheet of paper P from the top, as shown in (A) of Figure 13 (a diagram showing the state of the stack of paper 54 when air is blown). In this case, the second sheet P is lifted upward and urged toward the topmost sheet P. In this case, not only the topmost sheet P but also the second sheet P is sent out, which makes it easy for double feeding to occur.

[0104] In contrast, when the air volume is reduced as in the present embodiment, as shown in Fig. 13(B), air is less likely to get between the second sheet P and the third sheet P. In this case, the second sheet P is less likely to be biased toward the topmost sheet P, and double feeding is less likely to occur.

[0105] The amount of air blown to the tip side portion 510 may be zero (0), but it is preferable that the amount of air blown to the tip side portion 510 is not zero, and the output is reduced while air is blown to the tip side portion 510. The air blowing by the leading edge blowing mechanism 500 serves to separate the uppermost sheet P from the lower sheets P. If the air volume is set to zero, this separation becomes difficult to achieve. However, if air is blown to the leading edge side portion 510 while reducing the output, the function of separating the uppermost sheet P from the lower sheets P is maintained.

[0106] In the above, we have described a case in which the air volume is reduced when two conditions are met: the first condition that the paper P contained in the paper stack 54 satisfies a specific condition, and the second condition that the environment in which the paper feeding device 1B is installed satisfies a predetermined specific condition. However, the present invention is not limited to this, and the air volume may be reduced when one of these two conditions is satisfied.

[0107] Additionally, when the above two conditions are satisfied, CPU 103A may reduce the volume of air blown by side blowing mechanism 400 (see FIG. 4) against orthogonal side portion 401. Furthermore, when the above two conditions are satisfied, CPU 103A may stop side blowing mechanism 400 and set the volume of air blown against orthogonal side portion 401 to zero. By reducing or eliminating the volume of air blown by the side blowing mechanism 400 against the orthogonal side 401, the lower sheets P are less likely to be biased against the uppermost sheet P, and double feeding is less likely to occur. As described above, the reduction in the volume of air blown by the side blowing mechanism 400 toward the orthogonal side 401 is not limited to when both of the above two conditions are satisfied, and the reduction in the volume of air may be performed when either one of the two conditions is satisfied.

[0108] In addition, when the above two conditions are met, or when one of the two conditions is met, the CPU 103A may perform a process to reduce the airflow or to set the airflow to zero for both the side blowing mechanism 400 and the tip blowing mechanism 500. In addition, when the above two conditions are met, or when one of the two conditions is met, the CPU 103A may perform a process to reduce the airflow or to set the airflow to zero for only one of the side blowing mechanism 400 and the tip blowing mechanism 500.

[0109] From another perspective, in this embodiment, when the above two conditions are met, or when one of the two conditions is met, the CPU 103A changes the size of the blown area WA of the paper stack 54 onto which air is blown. Specifically, when the above two conditions are satisfied, or when one of the two conditions is satisfied, the CPU 103A changes the sprayed area WA from the state shown in (A) of Figure 14 (a diagram explaining the sprayed area WA) to the state shown in (B).

[0110] In this embodiment, the leading edge blowing mechanism 500 blows air onto a blown area WA extending in the vertical direction on a leading edge side portion 510 of the paper-stack 54, as shown in FIG. 14(A). When the above two conditions are satisfied, or when one of these two conditions is satisfied, the CPU 103A changes the size of this sprayed area WA.

[0111] Specifically, when the humidity at the location where the paper feeding device 1B is installed is lower than a predetermined threshold value, and / or when the value identified by information regarding the thickness of the paper P contained in the paper stack 54 is lower than a predetermined threshold value, the CPU 103A reduces the size of the sprayed area WA, as shown in FIG. 14(B). More specifically, for example, when the humidity at the location where the paper feeding device 1B is installed is less than 50% and / or when the basis weight of the paper P is less than 176 gsm, the CPU 103A reduces the size of the sprayed area WA, as shown in FIG. 14(B).

[0112] More specifically, CPU 103A reduces the size of blown area WA so that the width of blown area WA in the up-down direction becomes smaller, as shown in FIGS. 14(A) and 14(B). More specifically, as shown in Figures 14(A) and (B), CPU 103A changes the position of the lower end 98 of the sprayed area WA so that the position of the lower end 98 moves upward, thereby reducing the width of the sprayed area WA in the vertical direction and reducing the size of the sprayed area WA.

[0113] In this embodiment, the sprayed area WA is an area including the location where the uppermost sheet P is located, as shown in FIGS. The leading edge side blowing mechanism 500 blows air onto the blown area WA which extends in the vertical direction and which includes the location where the uppermost sheet P is located.

[0114] When changing the size of the sprayed area WA, CPU 103A changes the position of lower end 98 to change the size of the sprayed area WA, as described above. Furthermore, in this embodiment, the CPU 103A changes the size of the sprayed area WA without changing the position of the upper end 99 of the sprayed area WA, or even if it changes the position of the upper end 99, without moving the upper end 99 downward.

[0115] In this manner, in the present embodiment, when a specific condition is satisfied, CPU 103A moves the position of the lower end 98 of the sprayed area WA upward to reduce the size of the sprayed area WA. As a result, similarly to the above, and as shown in FIG. 14(B), air is less likely to get between the second sheet of paper P and the third sheet of paper P below the second sheet of paper P, making it less likely that double feeding will occur.

[0116] In this embodiment, when changing the size of the blown area WA, the CPU 103A changes the size of the blown area WA by changing the volume of air blown by the tip side blowing mechanism 500 against the tip side portion 510. More specifically, the CPU 103A reduces the volume of air blown by the tip side blowing mechanism 500 against the tip side portion 510, thereby reducing the size of the blown area WA, and increases the volume of air blown by the tip side blowing mechanism 500, thereby increasing the size of the blown area WA. More specifically, CPU 103A changes the amount of air flowing from air supply unit 150 toward guide surface 129, thereby changing the size of blown area WA.

[0117] As shown in FIG. 14(A), the tip side blowing mechanism 500 includes a guide surface 129. This guide surface 129 is a guide surface 129 that guides the air blown against the tip side portion 510, and is inclined (intersecting) with respect to the flow direction of the air flowing in one direction indicated by the arrow 14A. More specifically, guide surface 129 is inclined with respect to the flow direction of air flowing from air supply unit 150 toward guide surface 129 in one direction indicated by arrow 14A. CPU 103A changes the amount of this air flowing from air supply unit 150 toward guide surface 129, thereby changing the size of blown area WA.

[0118] Specifically, CPU 103A increases the amount of air flowing from air supply unit 150 toward guide surface 129, thereby increasing the size of blown area WA. 14(A), an air flow with a wide width W is generated. In this case, the air is blown over a wider range of the tip side portion 510, and the blown area WA becomes larger.

[0119] Furthermore, CPU 103A reduces the amount of air flowing from air supply unit 150 toward guide surface 129, thereby reducing the size of blown area WA, as shown in FIG. 14(B). When the amount of air heading toward guide surface 129 is small, the air flows in a laminar state along guide surface 129. In this case, an air flow with a narrower width W is generated compared to when the amount of air heading toward guide surface 129 is large. In this case, air is blown onto a narrower range of the tip side portion 510, and the size of the blown area WA becomes smaller.

[0120] The process of reducing the blown area WA may be performed by the side blowing mechanism 400 (see FIG. 4). If the area WA (not shown) of the paper stack 54 onto which the air is blown by the side blowing mechanism 400 is large, the air is blown over a wide area extending in the vertical direction. In this case, air gets between the papers P in this wide area extending in the vertical direction. This makes it difficult for double feeding to occur due to the papers P sticking to each other.

[0121] On the other hand, if the blown area WA is large, the lower sheet P is urged toward the uppermost sheet P, as in the above case, and double feeding is likely to occur. In this case, as with the above, when certain predetermined conditions are met, making the sprayed area WA smaller (reducing the vertical width of the sprayed area WA) makes it less likely that the paper P will move upward, and makes it less likely that the lower paper P will be forced toward the topmost paper P. As described above, the size of the sprayed area WA created by the side spray mechanism 400 may be changed when the above two conditions are satisfied, or when one of the two conditions is satisfied, as described above.

[0122] Alternatively, the size of the blown area WA may be changed by providing a shutter (movable member) that narrows the air flow path and moving the shutter. In this case, if the flow path is narrowed to reduce the size of the blown area WA, the air flow rate increases, and the increased flow rate makes it easier for the paper P to move upward. For this reason, when narrowing the flow path to reduce the size of the blown area WA, it is preferable to also reduce the air flow rate.

[0123] 15 and 16 are diagrams for explaining other processing examples. In the above, the occurrence of double feeding is suppressed by reducing the amount of air blown onto the paper stack 54 and by reducing the blown area WA. In addition to this, for example, the occurrence of double feeding can also be suppressed by changing the position of the guide surface 129 relative to the paper stack 54. In the paper feeder 1B of this embodiment, the suction unit 100 is provided to be movable, so that the position of the guide surface 129 relative to the paper stack 54 can be changed. In this processing example, the position of the guide surface 129 relative to the stack of paper-sheets 54 is changed to prevent the occurrence of double feeding.

[0124] Specifically, the sheet feeding device 1B of this embodiment is configured to be capable of taking at least two states: a first state shown in FIG. 15 and a second state shown in FIG. 15, a part (leading edge portion 2G) of the paper-sheet stack 54 is located opposite the guide surface 129. In the second state shown in FIG.

[0125] The CPU 103A moves the suction section 100 so that the stack of paper 54 is in one of two states: a first state in which a portion of the stack of paper 54 is located at a position opposite the guide surface 129, and a second state in which the stack of paper 54 is not located at a position opposite the guide surface 129. In this embodiment, the case where the suction section 100 is moved is described; however, for example, the stack of paper 54 may be moved, or both the stack of paper 54 and the suction section 100 may be moved, to switch from one of the above two states to the other. In other words, "changing the position of guide surface 129 relative to stack of paper 54" is not limited to a case where guide surface 129 is moved to change the position of guide surface 129 relative to stack of paper 54, but also includes a case where stack of paper 54 is moved to change the position of guide surface 129 relative to stack of paper 54.

[0126] In this processing example, CPU 103A changes the position of guide surface 129 with respect to stack of paper-sheets 54 when the environment in which paper-feeding device 1B is installed satisfies a specific condition that is determined in advance. Specifically, when the humidity at the location where the paper feeding device 1B is installed is greater than a predetermined threshold, the CPU 103A sets the paper stack 54 to a first state in which a portion of the paper stack 54 is positioned opposite the guide surface 129, as shown in FIG. 15.

[0127] In addition, when the humidity at the location where paper feeding device 1B is installed is lower than a predetermined threshold, CPU 103A sets the paper stack 54 to a second state in which a portion of the paper stack 54 is not positioned opposite guide surface 129, as shown in FIG. More specifically, when the humidity at the location where the paper feeding device 1B is installed is lower than a predetermined threshold value, the CPU 103A positions the leading edge 2G of the paper stack 54 opposite the other end 129B of the guide surface 129, as shown in FIG. 16, or positions the leading edge 2G closer to the uneven portion 121 than the other end 129B.

[0128] The inventors investigated whether or not double feeding occurred by successively changing the position of the guide surface 129 relative to the stack of paper-sheets 54. As a result, the inventor discovered that double feeding is less likely to occur by setting the first state when the humidity is greater than a predetermined threshold (e.g., 50%) and setting the second state when the humidity is less than the predetermined threshold.

[0129] Here, when the humidity was greater than a predetermined threshold, and the second state in which a portion of the paper stack 54 was not positioned opposite the guide surface 129 was used, more double feeding occurred than when the first state was used. In addition, when the humidity was lower than a predetermined threshold, multiple feeding occurred more frequently in the first state in which a part of the paper stack 54 was located at the position facing the guide surface 129 than in the second state.

[0130] In addition, a more preferred aspect of the above-mentioned "first state in which a part of paper stack 54 is located at a position facing guide surface 129" is an aspect in which leading edge 2G of paper stack 54 is located closer to the other end 129B than bottom 124S (the bottommost part of guide surface 129 which is formed in a concave shape) (see Figure 15), and this leading edge 2G is located closer to bottom 124S than the other end 129B. In other words, a more preferable embodiment is one in which, when comparing positions in the horizontal direction, leading edge portion 2G is located closer to other end portion 129B than bottom portion 124S, and is located closer to bottom portion 124S than other end portion 129B.

[0131] (others) In the above, as an example of the process for preventing double feeding, the process of reducing the air volume and / or reducing the blown area WA when a specific predetermined condition is satisfied has been described. Incidentally, even if this predetermined specific condition is satisfied, if another predetermined second condition is satisfied, the air volume may be increased midway through or the blown area WA may be enlarged.

[0132] Specifically, in this embodiment, as described above, when the humidity at the location where sheet feeding device 1B is installed is lower than a predetermined threshold, the air volume is reduced and the blown area WA is made smaller. In this case, if a predetermined second condition is satisfied, for example, when the stack of paper 54 is a stack of paper 54 immediately after being opened, the air volume may be increased midway through or the blown area WA may be enlarged. More specifically, for example, when a predetermined number of sheets P have been conveyed from the sheet stack 54, the air volume may be increased or the blown area WA may be enlarged.

[0133] Here, curling of the sheets P does not necessarily occur in all sheets P contained in the sheet stack 54. In the case of the sheet stack 54 immediately after opening as described above, the upper sheets P that are more likely to be exposed to the outside air are more likely to curl, but the sheets P other than the upper sheets P are less likely to curl. In this case, initially, the air volume is reduced and the blown area WA is made smaller, but after a predetermined number of sheets of paper have been transported, the process may be changed to increase the air volume and enlarge the blown area WA.

[0134] Moreover, in the above, the guide surface 129 that is curved and has a curvature has been described as an example. Incidentally, it is not essential to give a curvature to guide surface 129. As shown in FIG. 17 (a diagram showing another example of the configuration of guide surface 129), guide surface 129 may be formed flat without giving a curvature. Even if the guide surface 129 is formed flat, the guide surface 129 guides the air, and the air is blown against the side portion 510 on the leading end side of the stack of paper-sheets 54 .

[0135] In the above, the suction section 100 is moved to move the paper P toward the most upstream transport roll 52E, but this is not limited to the above. As shown in Figure 10 (a diagram showing another example configuration of the paper feed section 1C), the paper P may be moved toward the most upstream transport roll 52E without moving the suction section 100.

[0136] In this configuration example shown in FIG. 10, the suction section 100 is provided with a device body 101 having a lower surface 101X, and a belt member 190 that moves in a circulating manner. The device main body 101 is disposed inside the belt member 190, and furthermore, the belt member 190 is provided with a plurality of through holes (not shown) that connect the inside and outside of the belt member 190.

[0137] In this configuration example, when the paper sheet P is sucked by the device body 101, the paper sheet P adheres to the outer peripheral surface of the belt member 190. Here, in this configuration example, the surface of the outer peripheral surface of the belt member 190 facing downward becomes an adsorption portion to which the paper sheet P is adsorbed. Here, this adsorption portion is configured in a flat shape. When the paper sheet P adheres to the outer peripheral surface of the belt member 190, air is blown against the leading edge portion 2G of the paper sheet P in the same manner as described above. Then, the belt member 190 starts to rotate. As a result, the paper sheet P is supplied to the most upstream transport roll 52E.

[0138] In this configuration example, the rotation of the belt member 190 starts after the blowing of air to the leading edge portion 2G is stopped or the amount of air blown to the leading edge portion 2G is reduced. Additionally, in this configuration example, there is no functional part supporting the leading edge portion 2G from above, such as the air guide member 120 shown in FIG. 5, and as the paper sheet P passes the position opposite the discharge outlet 152A (see FIG. 10), the paper sheet P is likely to flutter due to the air blown against it. Therefore, in this configuration example, when the paper P is moved to the most upstream transport roll 52E, the blowing of air is stopped or the volume of the blown air is reduced.

[0139] As another embodiment, air may be blown directly onto the tip side portion 510 from above. In the above, air from the air supply source 151 located below is once moved upward, and then moved downward, and the air is blown from above against the tip side portion 510. However, the form of blowing is not limited to this. For example, an air supply source such as a fan may be provided above the lower surface 101X of the device body 101, and air may be supplied directly from above to the tip side portion 510. In this case, the recess 124 described above may be omitted.

[0140] Also, in the above description, an example has been described in which the sheet feeding device 1B is provided in the image forming apparatus 1. However, the sheet feeding device 1B is not limited to being provided in the image forming apparatus 1, and may be provided in another device that does not have an image forming function. For example, the above-described paper feeder 1B may be installed in a device that handles paper that has already been printed, such as banknotes. [Explanation of symbols]

[0141] 1...image forming apparatus, 1A...image forming section, 1B...paper feeder, 1C...paper delivery section, 54...paper stack, 98...lower end, 103A...CPU, 129...guide surface, 129A...one end, 129B...other end, 500...leading end blowing mechanism, 510...leading end side, P...paper, WA...blowing area

Claims

1. a sheet feeding means for feeding the topmost sheet included in the sheet stack; a blowing means for blowing gas onto a leading edge side portion, which is a side portion of the paper stack and is located at the leading edge in a paper feed direction by the paper feed means, the blowing means blowing the gas onto a guide surface that guides the gas toward the leading edge side portion to change the direction of the gas, and then blowing the gas onto the leading edge side portion; Equipped with When a predetermined condition is satisfied, the amount of gas blown onto the tip side portion by the blowing means is reduced, A paper feeder configured to change the position of the guide surface relative to the stack of paper in a paper feed direction by the paper feed means.

2. At least a part of the guide surface is located downstream of the paper stack in the paper feed direction, 2. The paper feeder according to claim 1, wherein at least one of the paper stack and the guide surface moves downstream and upstream in the feed direction, thereby changing the position of the guide surface relative to the paper stack.

3. The guide surface is disposed above the stack of paper sheets and faces downward; 3. A paper feeding device as described in claim 2, configured to be capable of taking at least two states: a first state in which a portion of the paper stack is located at a position opposite the guide surface, and a second state in which the paper stack is not located at a position opposite the guide surface.

4. The guide surface is formed to be convex upward, has a curvature, and has one end and an other end, 4. A paper feeding device as described in claim 3, wherein gas flows along the guide surface and from the one end side to the other end side, and then the gas leaves the guide surface and moves toward the tip side portion, where it is blown onto the tip side portion.

5. a processor for changing a position of the guide surface with respect to the stack of paper sheets; The paper feeder according to claim 1 , wherein the processor changes the position of the guide surface relative to the stack of paper in the feed direction when an environment in which the paper feeder is installed satisfies a predetermined specific condition.

6. a sheet feeding means for feeding the topmost sheet included in the sheet stack; a blowing means for blowing gas onto a leading edge side portion, which is a side portion of the paper stack and is located at the leading edge in a paper feed direction by the paper feed means, the blowing means blowing the gas onto a guide surface that guides the gas toward the leading edge side portion to change the direction of the gas, and then blowing the gas onto the leading edge side portion; an image forming section for forming an image on the paper fed by the paper feeding means; Equipped with When a predetermined condition is satisfied, the amount of gas blown onto the tip side portion by the blowing means is reduced, An image forming apparatus configured so that the position of the guide surface relative to the stack of sheets can be changed in the sheet sending direction by the sheet sending means.

Images