Sheet feeding device

Abstract

To provide a sheet feeder capable of reducing feeding failure of a sheet.SOLUTION: The conveyance unit 31 conveys the sheet P floated from the sheet bundle PT while holding the sheet P on the downward conveyance surface 46b. The curling amount detection part detects the curling amount of upward projecting curling along the carrying direction of the paper P held on the carrying surface 46b part. The inclination motor inclines the conveyance surface 46b so that the downstream side in the conveyance direction is higher than the upstream side. The control unit 11 controls the inclination motor so as to increase the inclination angle of the transport surface 46b as the curl amount detected by the curl amount detection unit increases.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device that feeds sheets. [Background technology]

[0002] 2. Description of the Related Art A sheet feeding device is known that blows air onto a sheet stack to lift the sheets, and then sucks and conveys the uppermost sheet of the lifted sheets by a suction and conveyance means to feed the sheet to a sheet supply destination.

[0003] In this type of sheet feeding device, if the sheet is curled, the sheet may come into contact with surrounding members, resulting in poor sheet feeding.

[0004] Patent Document 1 discloses a technology for reducing feeding problems caused by curled sheets. In this technology, after a sheet is attracted to a conveyor belt, the inclination angle of the inclined conveying surface of the conveyor belt is changed to raise the portion of the conveyor belt corresponding to the leading edge of the sheet. This makes it easier for air to enter between the top sheet and the next sheet, allowing for good separation and reducing feeding problems, even if the leading edge of the sheet is curled.

[0005] Another technique is disclosed in Patent Document 2. In this technique, the sheet tray is tilted to make the curl at the leading edge of the sheet closer to horizontal, allowing air to easily enter between the sheets. This allows the sheets to be lifted well, reducing poor adhesion of the sheets to the conveyor belt and enabling smooth sheet conveyance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-95543 [Patent Document 2] Japanese Patent Application Publication No. 10-1231 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the technology of Patent Document 1, the inclination angle of the inclined conveying surface is changed uniformly, so depending on the amount of curl in the sheet, the inclination angle may not be appropriate, and the sheet may not be separated properly, which may result in poor sheet feeding.

[0008] Furthermore, with the technology of Patent Document 2, even if the sheet tray is tilted, it is not possible to fully eliminate the effect of the curl of the sheet when the sheet is adsorbed onto the conveying belt, and there is a risk that the curled sheet may come into contact with surrounding components, resulting in poor sheet feeding.

[0009] The present invention has been made in view of the above, and has an object to provide a sheet feeding device that can reduce sheet feeding failures. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the sheet supply device of the present invention is characterized by comprising a conveying unit that holds a sheet that has floated up from a sheet stack on a downward-facing conveying surface and conveys it, a detection unit that detects the amount of upward convex curl along the conveying direction of the sheet held on the conveying surface, a tilt drive unit that tilts the conveying surface so that the downstream side in the conveying direction is higher than the upstream side, and a control unit that controls the tilt drive unit so that the tilt angle of the conveying surface increases as the amount of curl detected by the detection unit increases. [Effects of the Invention]

[0011] According to the sheet feeding device of the present invention, it is possible to reduce sheet feeding failures. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a paper feeder according to an embodiment; [Figure 2]FIG. 2 is a control block diagram of the paper feeder shown in FIG. [Figure 3] FIG. 2 is a schematic configuration diagram of an air paper feeding unit. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. 10 is a schematic diagram of the curl amount detection unit, showing a state in which an actuator of the curl amount detection unit is at a lower limit position. [Figure 7] FIG. 10 is a schematic diagram of the curl amount detection unit when the actuator is at the upper limit position. [Figure 8] 10 is a diagram showing the state in which the leading edge of the downwardly curled paper hits the separation gate. FIG. [Figure 9] FIG. 10 is a diagram showing a state in which the conveying surface of the conveying unit is inclined. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings.

[0014] The following embodiments are examples of devices that embody the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not limit the materials, shapes, structures, arrangements, etc. of each component to those described below. The technical idea of ​​the present invention can be modified in various ways within the scope of the claims.

[0015] FIG. 1 is a schematic diagram of a paper feeder according to an embodiment of the present invention. FIG. 2 is a control block diagram of the paper feeder shown in FIG. 1. FIG. 3 is a schematic diagram of an air paper feed unit of the paper feeder shown in FIG. 1. FIG. 4 is an enlarged view of the vicinity of the floating air outlet of the paper feeder shown in FIG. 1. FIG. 5 is an enlarged perspective view of the vicinity of the mounting plate of the paper feeder shown in FIG. 1. FIG. 6 is a schematic diagram of the curl amount detection unit of the paper feeder shown in FIG. 1, showing a state in which the actuator of the curl amount detection unit is in the lowermost position. FIG. 7 is a schematic diagram of the curl amount detection unit with the actuator in the uppermost position. In the following description, the direction perpendicular to the plane of the paper in FIG. 1 is defined as the front-to-rear direction, and the front direction of the paper is defined as the front. Furthermore, the up, down, left, and right directions of the plane of the paper in FIG. 1 are defined as the up, down, left, and right directions.

[0016] As shown in Figures 1 and 2, the paper feeding device (corresponding to a sheet supplying device) 1 of this embodiment includes a paper feed tray 2, a paper feed guide plate 3, a separation gate 4, an end fence 5, a floating section 6, a separation section 7, an air paper feed unit 8, an inclined motor (corresponding to an inclined drive section) 9, a curl amount detection section (corresponding to a detection section) 10, and a control section 11.

[0017] The paper feeder 1 is a device that feeds (supplies) paper (corresponding to a sheet) P to a printing device (not shown). The direction from left to right in Fig. 1 is the direction in which paper P is conveyed by a conveying section 31 of an air paper feed unit 8, which will be described later. In the following description, upstream and downstream refer to upstream and downstream in the direction in which paper P is conveyed by the conveying section 31.

[0018] The paper feed tray 2 is configured to be able to move up and down by a motor (not shown) on which paper sheets P to be fed to the printing device are stacked.

[0019] The paper feed guide plate 3 is a member that regulates the position of the downstream end (right end) of the paper P on the paper feed tray 2. The paper feed guide plate 3 is disposed near the downstream side of the paper feed tray 2. The upper end of the paper feed guide plate 3 is inclined so that it is higher on the downstream side. Also, as shown in FIG. 4, the paper feed guide plate 3 has a cutout portion 3a formed by cutting out the upper center portion in the front-to-rear direction to blow air from the floating portion 6 onto the paper P on the paper feed tray 2.

[0020] The separation gate 4 is a member that blocks all of the sheets P floated by the floating portion 6 except for the topmost sheet P that is adsorbed to the conveying section 31. As shown in Fig. 3, the separation gate 4 is disposed near the lower end of the downstream end of the conveying section 31. As shown in Fig. 4, two separation gates 4 are installed spaced apart from each other in the front-to-rear direction.

[0021] The end fence 5 is a member that regulates the position of the upstream end (left end) of the paper P on the paper feed tray 2.

[0022] The floating section 6 blows air onto a paper stack (corresponding to a sheet stack) PT consisting of multiple sheets of paper P stacked on the paper feed tray 2 by driving a fan not shown, thereby floating up the multiple sheets of paper P at the top end of the paper stack PT.

[0023] The floating section 6 has two floating air outlets 21, which are air outlets for floating the sheets P of the sheet stack PT. As shown in Fig. 3, the floating air outlets 21 are arranged near the lower downstream end of the conveying section 31. As shown in Fig. 4, the two floating air outlets 21 are arranged spaced apart from each other in the front-to-rear direction.

[0024] The floating part 6 also has a shutter (not shown) that switches between blowing air from the floating air outlet 21 and stopping the blowing.

[0025] The separation section 7 blows out air by driving a fan (not shown) to separate the topmost sheet P floated by the floating section 6 and held in the conveying section 31 from the second and subsequent sheets P from the top.

[0026] The separation section 7 has two separation air outlets 26, which are air outlets for separating the uppermost sheet P from the second and subsequent sheets P. As shown in Fig. 3, the separation air outlets 26 are located near the lower downstream end of the conveyance section 31. As shown in Fig. 4, the two separation air outlets 26 are located spaced apart from each other in the front-to-rear direction.

[0027] The air paper feed unit 8 uses air suction to hold and transport the uppermost sheet P of multiple sheets P that have been floated from the stack of sheets PT by air blown out from the floating section 6. As shown in Figures 3 and 4, the air paper feed unit 8 includes a transport section 31, a chamber 32, and a suction fan 33. Note that in Figure 4, illustration of a metal plate 51 and the like, which will be described later, is omitted.

[0028] The transport section 31 holds and transports the paper P. The transport section 31 has two belt units 41 arranged side by side in the front-rear direction.

[0029] The belt unit 41 includes a conveyor belt 46, a drive roller 47, and a driven roller 48.

[0030] The conveyor belt 46 is a circular belt that is stretched over a drive roller 47 and a driven roller 48. A plurality of belt holes 46a are formed around the entire circumference of the conveyor belt 46. The conveyor belt 46 holds the paper P on the conveying surface 46b by the suction force generated in the belt holes 46a by the drive of the suction fan 33.

[0031] The conveying surface 46b is a downward-facing horizontal surface that is the lower surface of the lower part of the conveying belt 46 between the driving roller 47 and the driven roller 48. With the paper P held on the conveying surface 46b, the conveying belt 46 rotates (moves endlessly) due to the driving of the driving roller 47, thereby conveying the paper P.

[0032] The drive roller 47 rotates the conveyor belt 46. The drive rollers 47 of the two belt units 41 are connected to each other by a shaft 49. The shaft 49 is rotated by the drive of a motor (not shown), which causes the drive rollers 47 of the two belt units 41 to rotate.

[0033] The driven roller 48 supports the conveyor belt 46 together with the drive roller 47. The driven roller 48 rotates following the rotation of the rotating conveyor belt 46. The driven rollers 48 of the two belt units 41 are connected to each other by a shaft 50.

[0034] The chamber 32 forms a negative pressure chamber for generating an adhesive force at the belt holes 46a of the conveyor belt 46. The chamber 32 holds the belt unit 41 and the curl amount detection unit 10 inside so that the conveying surface 46b of the conveyor belt 46 and a paper contact portion 66 of the curl amount detection unit 10 (described later) are exposed to the outside. A ventilation hole (not shown) is formed in the bottom plate of the chamber 32 at a portion where the conveyor belt 46 passes. Air is sucked into the chamber 32 through the belt holes 46a of the conveyor belt 46 and the ventilation hole of the chamber 32, generating an adhesive force at the belt holes 46a.

[0035] The suction fan 33 exhausts air from the chamber 32. When the suction fan 33 exhausts air from the chamber 32, air is sucked into the chamber 32 from outside the chamber 32 through the belt holes 46a in the conveying surface 46b of the conveyor belt 46 and the ventilation holes in the chamber 32. The suction fan 33 is disposed above the chamber 32.

[0036] 3 and 5, a metal plate 51 is attached to the air paper feed unit 8. A mounting plate 53 is connected to the right end of the metal plate 51 by a suction shaft 52. The mounting plate 53 is connected to a support plate 54 arranged inside the paper feeder 1 so as to be movable up and down.

[0037] This allows the air paper feed unit 8 to be tilted so that the downstream side (right side) is higher than the upstream side (left side).As a result, the conveying surface 46b of the conveying section 31 can also be tilted so that the downstream side (right side) is higher than the upstream side (left side).

[0038] The left end of air feeding unit 8 is suspended via an interlock switch. Even if the right end of air feeding unit 8 moves up and down due to the vertical movement of mounting plate 53, the height position of the left end does not change.

[0039] The tilt motor 9 moves the mounting plate 53 up and down to tilt the air paper feed unit 8 (transport surface 46b) so that the downstream side is higher than the upstream side, and adjusts the tilt angle.

[0040] The curl amount detection unit 10 detects the amount of downward curl, which is an upward convex curl along the conveyance direction of the sheet P held on the conveyance surface 46b. The curl amount detection unit 10 is disposed between the two belt units 41 in the front-rear direction. In the left-right direction, the curl amount detection unit 10 is disposed at the right end of the belt unit 41. As shown in FIG. 6, the curl amount detection unit 10 includes an actuator 61 and a sensor unit 62.

[0041] The actuator 61 includes a paper contact portion 66 , a slit plate 67 , and a rotation shaft 68 .

[0042] The paper contact portion 66 comes into contact with the paper P held on the transport surface 46b and is pushed up by the paper P. The paper contact portion 66 rotates around a rotation shaft 68, so that the paper P pushes up.

[0043] The slit plate 67 is a sector-shaped plate having a plurality of slits 67a and is fixed to a rotation shaft 68 so as to rotate around the rotation shaft 68.

[0044] The rotation shaft 68 extends in the front-rear direction and holds the paper contact portion 66 and the slit plate 67 in a rotatable manner.

[0045] Here, in a state such as that shown in Figure 6 where no paper P is held on the conveying surface 46b, the weight of the actuator 61 (paper contact portion 66) is designed to be positioned at the lowest position by its own weight, so that the actuator 61 does not become a resistance to the paper being attracted to the conveying surface 46b.

[0046] When the sheet P is not curled (the curl amount is zero) and is attracted to the transport surface 46b, the actuator 61 is pushed up to the upper limit position by the sheet P, as shown in FIG.

[0047] The sensor unit 62 has a light-emitting element and a light-receiving element (neither shown) arranged opposite each other with a slit plate 67 in between. The light-emitting element emits light toward the light-receiving element. When the slit plate 67 rotates, the light from the light-emitting element passes through the slit 67a or is blocked by the slit plate 67. The light-receiving element receives the light from the light-emitting element that has passed through the slit 67a and outputs an electrical signal corresponding to the amount of light received. If the amount of light received by the light-receiving element is equal to or greater than a threshold, the slits 67a are detected. Then, when the actuator 61 moves from the lower limit position and the slit plate 67 rotates as the sheet P is attracted to the transport surface 46b, the number of slits 67a corresponding to the amount of curl of the sheet P is detected.

[0048] The control unit 11 controls the overall operation of the sheet feeding device 1. The control unit 11 includes a CPU, RAM, ROM, a hard disk, and the like.

[0049] Specifically, the control unit 11 causes the floating unit 6 to float the sheet P at the top end of the stack of sheets PT on the sheet feed tray 2, causing the topmost sheet P to be adsorbed to the conveyor belt 46. Thereafter, the control unit 11 controls the inclination motor 9 to increase the inclination angle of the conveyor surface 46b as the curl amount of the sheet P adsorbed to the conveyor surface 46b detected by the curl amount detection unit 10 increases. Then, the control unit 11 drives the conveyor unit 31 to convey the sheet P toward the printing device.

[0050] Next, the operation of the paper feeder 1 will be described.

[0051] When feeding paper, the control unit 11 starts driving the floating unit 6, the separating unit 7, and the suction fan 33.

[0052] As a result, air is blown out from the floating air outlet 21 and the separation air outlet 26. Also, an attraction force is generated in the belt holes 46a of the conveyor belt 46.

[0053] The air blown out from the floating air outlet 21 causes the uppermost sheets P of the sheet stack PT to float from the sheet stack PT, and the uppermost sheet P among them is adsorbed to the conveyance surface 46b of the conveyance belt 46.

[0054] Here, before the paper sheet P starts to float, the actuator 61 of the curl amount detection unit 10 is located at the lowest position due to its own weight. When the floated paper sheet P is attracted to the transport surface 46b as described above, the paper sheet P pushes up the paper sheet contact unit 66, causing the paper sheet contact unit 66 and the slit plate 67 to rotate. At this time, the sensor unit 62 detects the number of slits 67a corresponding to the amount of curl of the paper sheet P attracted to the transport surface 46b. The control unit 11 determines the amount of curl of the paper sheet P based on the number of slits 67a detected by the sensor unit 62.

[0055] Next, the control unit 11 determines the inclination angle of the transport surface 46b of the transport unit 31 based on the amount of curl of the paper sheet P. Here, the greater the amount of curl of the paper sheet P, the greater the inclination angle of the transport surface 46b.

[0056] Then, the control unit 11 controls the tilt motor 9 to adjust the position of the mounting plate 53 so that the tilt angle of the conveying surface 46b becomes the determined tilt angle.

[0057] Next, the control unit 11 closes the shutter of the floating unit 6 to stop the air from being blown out from the floating air outlet 21. As a result, the uppermost sheet P is separated from the second and subsequent sheets P by the air blown out from the separation air outlet 26 of the separation unit 7, and the second and subsequent sheets P fall.

[0058] Next, the control unit 11 drives the conveying unit 31 to convey the paper P.

[0059] Here, unlike the present embodiment, if the conveying surface 46b of the conveying section 31 is not inclined and is always horizontal, then uncurled paper P, such as paper P shown by the thick two-dot chain line in Fig. 8, will pass through the separation gate 4 and be fed. However, paper P that is curled downward, such as paper P shown by the thick solid line, may not be sufficiently adsorbed at its leading edge, as shown in Fig. 8, and the leading edge of the paper P may hit the separation gate 4 and not be fed.

[0060] 9, even when the paper P is curled downward, the leading edge of the paper P is raised by tilting the conveying surface 46b at an angle corresponding to the amount of curl of the paper P. This makes it possible to feed the paper P without the leading edge hitting the separation gate 4, even when the paper P is curled downward.

[0061] Next, the control unit 11 opens the shutter of the floating unit 6 to float the next sheet P in order to feed the next sheet P.

[0062] By repeating the above operation, the sheets P are sequentially fed from the sheet feeder 1 to the printing device. When the printing device has finished feeding the number of sheets to be printed, the series of operations ends.

[0063] As described above, in the paper feeder 1, the control unit 11 controls the tilt motor 9 so that the tilt angle of the conveying surface 46b increases as the curl amount of the paper P detected by the curl amount detection unit 10 increases. This reduces the likelihood that the leading edge of the paper P that is curled downward will hit the separation gate 4. As a result, feeding failures of the paper P can be reduced.

[0064] Furthermore, since feeding problems can be prevented even if the paper P is curled, the storage environment for the paper P does not need to be strictly specified.

[0065] In the above-described embodiment, a paper feeder that feeds paper has been described, but the present invention can also be applied to a device that feeds sheets other than paper.

[0066] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments.

[0067] [Note] The present application discloses the following inventions.

[0068] (Appendix 1) a conveying section that holds a sheet that has floated from the sheet stack on a downward conveying surface and conveys the sheet; a detection unit that detects the amount of upward convex curl along the conveyance direction of the sheet held on the conveyance surface; a tilt drive unit that tilts the conveying surface so that the downstream side in the conveying direction is higher than the upstream side; a control unit that controls the tilt drive unit so that the tilt angle of the conveying surface increases as the curl amount detected by the detection unit increases; A sheet feeding device comprising: [Explanation of symbols]

[0069] 1 Paper feeder 2 Paper feed tray 3 Paper feed guide plate 4 Sabaki Gate 5 End Fence 6 Floating section 7 Separation part 8 Air feeding unit 9 Inclined Motor 10 Curl amount detection unit 11 Control section 31 Conveyor 32 Chamber 33 Suction fan 41 Belt unit 46 Conveyor belt 46a belt hole 46b Conveying surface 61 Actuator 62 Sensor section 66 Paper contact part 67 Slit Plate 67a Slit 68 Rotating shaft

Claims

[Claim 1] a conveying section that holds a sheet that has floated from the sheet stack on a downward conveying surface and conveys the sheet; a detection unit that detects the amount of upward convex curl along the conveyance direction of the sheet held on the conveyance surface; a tilt drive unit that tilts the conveying surface so that the downstream side in the conveying direction is higher than the upstream side; a control unit that controls the tilt drive unit so that the tilt angle of the conveying surface increases as the curl amount detected by the detection unit increases; A sheet feeding device comprising:

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