Sheet feeding device

Abstract

To provide a sheet feeding device capable of reducing erroneous detection of sheet sizes.SOLUTION: A side guide 3 regulates the position of paper P loaded in a paper tray 2. The side guide 3 is movable in the front-to-rear direction. Detection electrodes 5A to 5C are each formed by a pair of electrodes 16A and 16B, and are each arranged at a predetermined position in the paper tray 2. A capacitance detection unit 7 detects the capacitance of each of the detection electrodes 5A to 5C. A control unit 8 detects the size of the paper P in the front-to-rear direction and the position of the side guide 3 based on the capacitance of each of the detection electrodes 5A to 5C detected by the capacitance detection unit 7.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] 2. Description of the Related Art As a sheet feeding device for feeding sheets, a paper feeding device that feeds sheets loaded in a paper tray to a printing device is known.

[0003] In such a paper feeder, a technique is known in which the size of the paper is detected by detecting the position of a movable paper guide that regulates the position of the paper loaded in the paper tray.

[0004] One such technology is disclosed in Patent Document 1. The image forming apparatus disclosed in Patent Document 1 includes a conductor provided on a paper guide, a first electrode and a second electrode positioned opposite the conductor, and a capacitance detector that outputs a signal according to the amount of electricity stored in the first electrode and the second electrode.

[0005] In this image forming device, as the position of the paper guide changes, the opposing area between the conductor and the first and second electrodes changes. This changes the output signal of the capacitance detector, which in turn changes the capacitance value detected from that output signal. Therefore, this image forming device detects the position of the paper guide from the capacitance value and determines the paper size from the position of the paper guide. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-83593 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the technology of Patent Document 1 does not directly detect the size of the paper, and therefore may misdetect the size of the paper. For example, if the user forgets to operate the paper guide or sets the paper guide in an inappropriate position, the misdetection of the size of the paper may occur.

[0008] The present invention has been made in view of the above, and has an object to provide a sheet feeding device that can reduce erroneous detection of sheet size. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the sheet supply device of the present invention is characterized by comprising a movable guide that regulates the position of sheets loaded on a tray, a plurality of detection electrodes each formed by a pair of electrodes and each arranged at a predetermined position on the tray, a capacitance detection unit that detects the capacitance of each of the plurality of detection electrodes, and a control unit that detects the size of the sheet in the movement direction of the guide and the position of the guide based on the capacitance of each of the plurality of detection electrodes detected by the capacitance detection unit. [Effects of the Invention]

[0010] According to the sheet feeding device of the present invention, it is possible to reduce erroneous detection of the size of the sheet. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view showing a schematic configuration of a paper feed device according to an embodiment; [Figure 2] FIG. 2 is a plan view of the paper feeder shown in FIG. [Figure 3] FIG. 10 is a diagram illustrating an example of the capacitance of a detection electrode. [Figure 4] 10A and 10B are diagrams illustrating other examples of the capacitance of the detection electrode. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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.

[0013] 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.

[0014] Fig. 1 is a side view showing a schematic configuration of a paper feeder according to an embodiment of the present invention. Fig. 2 is a plan view of the paper feeder shown in Fig. 1. In the following description, the direction perpendicular to the plane of Fig. 1 is referred to as the front-rear direction, and the front direction of the plane of Fig. 1 is referred to as the forward direction. Furthermore, the up-down and left-right directions of the plane of Fig. 1 are referred to as the up-down and left-right directions.

[0015] 1 and 2, a paper feeder (corresponding to a sheet supplying device) 1 according to this embodiment includes a paper tray (corresponding to a tray) 2, a pair of side guides (corresponding to guides) 3, an end guide (corresponding to a guide) 4, three pairs of detection electrodes 5A, 5B, and 5C, detection electrodes 6A, 6B, and 6C, a capacitance detection unit 7, and a control unit 8. Note that the alphabetical subscripts in the reference numerals of the detection electrodes 5A to 5C may be omitted to collectively represent them.

[0016] The paper tray 2 is used to stack paper sheets P to be fed to a printing device (not shown). Paper sheets P are stacked centered on the stacking surface 2a, which is the top surface of the paper tray 2. Centering is an alignment in which the center line of the paper sheets P in the front-to-back direction coincides with the center line C of the paper tray 2 in the front-to-back direction. The paper sheets P stacked on the stacking surface 2a are transported from left to right by a transport mechanism (not shown), such as a transport roller, and are fed to the printing device.

[0017] The pair of side guides 3 regulates the front-to-rear position of the paper P loaded in the paper tray 2. The pair of side guides 3 are erected on the paper tray 2, parallel to each other in the front-to-rear direction with a center line C in between. The pair of side guides 3 are spaced from each other the same distance from the center line C. The pair of side guides 3 are configured to be movable in conjunction with each other in the front-to-rear direction, symmetrically across the center line C, by manual operation by the user. That is, when one side guide 3 moves away from the center line C, the other side guide 3 also moves away from the center line C, and when one side guide 3 moves closer to the center line C, the other side guide 3 also moves closer to the center line C. A conductor 11 made of metal such as an iron plate is disposed at the lower end of the side guide 3. The conductor 11 is covered with an insulating layer.

[0018] The end guide 4 regulates the left-right position of the paper P loaded in the paper tray 2. The end guide 4 is erected in the center of the loading surface 2a of the paper tray 2 in the front-to-rear direction. The end guide 4 is configured to be movable left-to-right by manual operation by the user. A conductor 12 made of metal such as an iron plate is disposed at the lower end of the end guide 4. Like the conductor 11, the conductor 12 is covered with an insulating layer.

[0019] Each of the detection electrodes 5A to 5C is formed by a pair of electrodes 16A and 16B. The electrodes 16A and 16B are arranged at the same height. The detection electrodes 5A to 5C are arranged below the loading surface 2a. The detection electrodes 5A to 5C are covered with an insulating layer.

[0020] Here, to avoid a short circuit that may occur when conductor 11 is positioned directly above detection electrode 5, making it impossible to determine the capacitance, conductor 11 and detection electrodes 5A to 5C are covered with an insulating layer as described above.

[0021] The pair of detection electrodes 5A are arranged spaced apart in the front-rear direction across the center line C. The pair of detection electrodes 5B are arranged spaced apart in the front-rear direction across the detection electrode 5A. The pair of detection electrodes 5C are arranged spaced apart in the front-rear direction across the detection electrodes 5A and 5B.

[0022] The detection electrodes 5A to 5C are each disposed at a predetermined position in the front-rear direction. Specifically, the detection electrode 5A is disposed in a position where it is covered by a first-size sheet P placed centered on the stacking surface 2a. The detection electrode 5B is disposed in a position facing the conductor 11 of the side guide 3, which is disposed in a position that regulates the position of the first-size sheet P in the front-rear direction. The detection electrode 5C is disposed in a position facing the conductor 11 of the side guide 3, which is disposed in a position that regulates the position of a second-size sheet P that is larger than the first size in the front-rear direction.

[0023] Like the detection electrodes 5A to 5C, the detection electrodes 6A to 6C are each formed of a pair of electrodes 16A and 16B. The detection electrodes 6A to 6C are arranged below the stacking surface 2a in the center of the paper tray 2 in the front-to-rear direction. The detection electrodes 6A to 6C are covered with an insulating layer.

[0024] Here, for the same reason that the conductor 11 and the detection electrodes 5A to 5C are covered with an insulating layer, the conductor 12 and the detection electrodes 6A to 6C are covered with an insulating layer, as described above.

[0025] Detection electrode 6B is disposed to the left of detection electrode 6A, and detection electrode 6C is disposed to the left of detection electrode 6B. Detection electrodes 6A to 6C are disposed at predetermined positions in the left-right direction. Specifically, detection electrode 6A is disposed in a position where it is covered by a first-size sheet P placed with its right edge aligned with the right edge of stacking surface 2a. Detection electrode 6B is disposed in a position opposite conductor 12 of end guide 4, which is disposed in a position to restrict the left edge of the first-size sheet P. Detection electrode 6C is disposed in a position opposite conductor 12 of end guide 4, which is disposed in a position to restrict the left edge of the second-size sheet P.

[0026] The capacitance detection unit 7 detects the capacitance of each of the detection electrodes 5A to 5C and 6A to 6C.

[0027] The control unit 8 controls the overall operation of the sheet feeding device 1. The control unit 8 includes a CPU, a memory, and the like.

[0028] When performing a paper feeding operation, the control unit 8 detects the size (paper width) of the paper P in the front-to-rear direction, which is the direction in which the side guide 3 moves, and the position of the side guide 3 based on the capacitance of each of the detection electrodes 5A to 5C detected by the capacitance detection unit 7.

[0029] In addition, when performing a paper feeding operation, the control unit 8 detects the size (paper length) of the paper P in the left-right direction, which is the direction of movement of the end guide 4, and the position of the end guide 4 based on the capacitance of each of the detection electrodes 6A to 6C detected by the capacitance detection unit 7.

[0030] Next, the operation of the paper feeder 1 will be described.

[0031] When the paper feeding device 1 performs a paper feeding operation, the control unit 8 acquires the capacitances of the detection electrodes 5A to 5C and 6A to 6C detected by the capacitance detection unit .

[0032] Here, when there is paper P directly above the detection electrode 5, the capacitance of the detection electrode 5 becomes larger than when there is no paper P, because the dielectric constant of paper is greater than that of air. Furthermore, when there is a side guide 3 directly above the detection electrode 5, the detection electrode 5 faces the conductor 11, so it can be considered that the distance between electrodes 16A and 16B of the detection electrode 5 is shorter than when there is paper P, and the capacitance of the detection electrode 5 becomes even larger.

[0033] Similarly, when there is paper P directly above the detection electrode 6, the capacitance is larger than when there is no paper P. Furthermore, when there is an end guide 4 directly above the detection electrode 6, the capacitance of the detection electrode 6 is even larger than when there is paper P.

[0034] From the above, the control unit 8 determines the presence or absence of the paper sheet P and the side guide 3 at the positions of the detection electrodes 5A to 5C based on the capacitance of each of the detection electrodes 5A to 5C. The control unit 8 also determines the presence or absence of the paper sheet P and the end guide 4 at the positions of the detection electrodes 6A to 6C based on the capacitance of each of the detection electrodes 6A to 6C.

[0035] Specifically, control unit 8 compares the capacitance of each of detection electrodes 5A to 5C with determination values ​​C1 and C2. Determination value C1 is a value set as the upper limit of the capacitance of detection electrode 5 when paper P is present at the position of detection electrode 5. Determination value C2 is a value set as the lower limit of the capacitance of detection electrode 5 when paper P is present at the position of detection electrode 5.

[0036] If the capacitance of detection electrode 5A is greater than or equal to determination value C2 and less than determination value C1, control unit 8 determines that paper P is present at the position of detection electrode 5A. If the capacitance of detection electrode 5A exceeds determination value C1, control unit 8 determines that side guide 3 is present at the position of detection electrode 5A. If the capacitance of detection electrode 5A is less than determination value C2, control unit 8 determines that neither paper P nor side guide 3 is present at the position of detection electrode 5A. Control unit 8 similarly determines the presence or absence of paper P and side guide 3 at each position for detection electrodes 5B and 5C.

[0037] 3, assume that the capacitance of detection electrode 5A is equal to or greater than determination value C2 and equal to or less than determination value C1, the capacitance of detection electrode 5B exceeds determination value C1, and the capacitance of detection electrode 5C is less than determination value C2. In this case, control unit 8 determines that there is paper P at the position of detection electrode 5A, there is side guide 3 at the position of detection electrode 5B, and there is neither paper P nor side guide 3 at the position of detection electrode 5C.

[0038] In the example of FIG. 3, the side guide 3 is disposed at the position of the detection electrode 5B for the first size paper P, and the side guide 3 is disposed at an appropriate position for the size of the paper P.

[0039] 4, for example, assume that the capacitance of detection electrode 5A is equal to or greater than determination value C2 and equal to or less than determination value C1, the capacitance of detection electrode 5B is less than determination value C2, and the capacitance of detection electrode 5C is greater than determination value C1. In this case, control unit 8 determines that there is paper P at the position of detection electrode 5A, there is neither paper P nor side guide 3 at the position of detection electrode 5B, and there is side guide 3 at the position of detection electrode 5C.

[0040] In the example of FIG. 4, for a first size sheet of paper P, the side guide 3 is positioned at the position of the detection electrode 5C away from the sheet of paper P, and the side guide 3 is positioned in an inappropriate position for the size of the sheet of paper P. If the user forgets to operate the side guide 3 or sets the side guide 3 in an inappropriate position, the side guide 3 may be positioned in an inappropriate position for the size of the sheet of paper P, as in the example of FIG. 4.

[0041] Furthermore, control unit 8 compares the capacitance of each of detection electrodes 6A to 6C with determination values ​​C3 and C4. Determination value C3 is a value set as the upper limit of the capacitance of detection electrode 6 when paper P is present at the position of detection electrode 6. Determination value C4 is a value set as the lower limit of the capacitance of detection electrode 6 when paper P is present at the position of detection electrode 6.

[0042] If the capacitance of detection electrode 6A is equal to or greater than determination value C4 and equal to or less than determination value C3, control unit 8 determines that paper P is present at the position of detection electrode 6A. If the capacitance of detection electrode 6A exceeds determination value C3, control unit 8 determines that end guide 4 is present at the position of detection electrode 6A. If the capacitance of detection electrode 6A is less than determination value C4, control unit 8 determines that neither paper P nor end guide 4 is present at the position of detection electrode 6A. Control unit 8 similarly determines the presence or absence of paper P and end guide 4 at each position for detection electrodes 6B and 6C.

[0043] Here, like the side guide 3, the end guide 4 may also be placed at an inappropriate position for the size of the paper P.

[0044] Then, the control unit 8 determines the size of the paper P in the front-to-rear direction (paper width) and the position of the side guide 3 based on the results of determining the presence or absence of the paper P and the side guide 3 at each position of the detection electrodes 5A to 5C as described above.

[0045] In the example of FIG. 3, the control unit 8 determines that the size (paper width) of the paper P in the front-rear direction is the size (paper width) in the front-rear direction of the first size, and the position of the side guide 3 is the position of the detection electrode 5B.

[0046] In the example of FIG. 4, the control unit 8 determines that the size (paper width) of the paper P in the front-rear direction is the size (paper width) in the front-rear direction of the first size, and the position of the side guide 3 is the position of the detection electrode 5C.

[0047] Furthermore, the control unit 8 determines the size of the paper P in the left-right direction (paper length) and the position of the end guide 4 based on the results of determining the presence or absence of the paper P and the end guide 4 at each position of the detection electrodes 6A to 6C as described above.

[0048] Here, for example, assume that the control unit 8 determines that there is paper P at the position of the detection electrode 6A, that there is end guide 4 at the position of the detection electrode 6B, and that there is neither paper P nor end guide 4 at the position of the detection electrode 6C. In this case, the control unit 8 determines that the size of the paper P in the left-right direction (paper length) is the left-right size (paper length) of the first size, and that the position of the end guide 4 is the position of the detection electrode 6B.

[0049] Also, for example, suppose that the control unit 8 determines that there is paper P at the position of detection electrode 6A, that there is neither paper P nor end guide 4 at detection electrode 6B, and that there is end guide 4 at the position of detection electrode 6C. In this case, the control unit 8 determines that the size of paper P in the left-right direction (paper length) is the left-right size (paper length) of the first size, and that the position of end guide 4 is the position of detection electrode 6C.

[0050] As described above, the control unit 8 detects the size of the paper P (paper width and paper length), the position of the side guide 3, and the position of the end guide 4.

[0051] If the positions of the side guides 3 and end guide 4 are appropriate for the detected size of the paper P (paper width and paper length), the control unit 8 notifies the printing device of the detected size of the paper P and starts the paper feeding operation.

[0052] If the position of at least one of the side guide 3 and the end guide 4 is inappropriate for the detected size of the paper P (paper width and paper length), the control unit 8 outputs an alert to the printing device and stops the paper feeding operation.

[0053] As described above, in the paper feeding device 1, the control unit 8 detects the size of the paper P in the front-to-rear direction (paper width) and the position of the side guide 3 based on the capacitance of each of the detection electrodes 5A to 5C detected by the capacitance detection unit 7. The control unit 8 also detects the size of the paper P in the left-to-right direction (paper length) and the position of the end guide 4 based on the capacitance of each of the detection electrodes 6A to 6C detected by the capacitance detection unit 7.

[0054] In this way, by detecting the positions of the side guide 3 and the end guide 4 and directly detecting the size of the paper P, it is possible to reduce erroneous detection of the size of the paper P. As a result, it is possible to prevent paper P from being fed into the printing device with an incorrect size setting, and reduce paper waste and paper jams that would otherwise cause the printing operation of the printing device to stop.

[0055] Furthermore, since the detection electrodes 5A to 5C and 6A to 6C are provided on the paper tray 2, the risk of the wiring being broken can be reduced compared to when electrodes are provided on a movable part.

[0056] The conductor 11 of the side guide 3 may be omitted. Even in this case, it is possible to determine whether the side guide 3 or the paper P is present at the position of the detection electrode 5 based on the difference in dielectric constant between the resin or other material that forms the side guide 3 and the paper P. Similarly, the conductor 12 of the end guide 4 may be omitted. However, since the dielectric constant of the paper P is thought to be affected by humidity, it is preferable to provide the conductor 11 of the side guide 3 and the conductor 12 of the end guide 4.

[0057] Furthermore, the insulating layer covering the conductor 11 or the insulating layer covering the detection electrodes 5A to 5C may be omitted. Furthermore, the insulating layer covering the conductor 12 or the insulating layer covering the detection electrodes 6A to 6C may be omitted.

[0058] Furthermore, the detection electrodes 5A to 5C or the detection electrodes 6A to 6C may be omitted. Even in this case, it is possible to detect the position of the side guide 3 in the front-to-rear direction and directly detect the size of the paper P (paper width), or to detect the position of the end guide 4 in the left-to-right direction and directly detect the size of the paper P (paper length). This reduces erroneous detection of the size of the paper P.

[0059] Furthermore, 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.

[0060] 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.

[0061] [Note] The present application discloses the following inventions.

[0062] (Appendix 1) a movable guide for regulating the position of the sheets loaded on the tray; a plurality of detection electrodes each formed by a pair of electrodes and each disposed at a predetermined position on the tray; a capacitance detection unit that detects the capacitance of each of the plurality of detection electrodes; a control unit that detects the size of the sheet in the moving direction of the guide and the position of the guide based on the capacitance of each of the plurality of detection electrodes detected by the capacitance detection unit; A sheet feeding device comprising: [Explanation of symbols]

[0063] 1 Paper feeder 2 Paper Trays 2a Loading surface 3 Side guide 4 End guide 5,5A,5B,5C,6,6A,6B,6C detection electrode 7 Capacitance detection unit 8 Control Unit 11,12 Conductor 16A,16B electrode

Claims

[Claim 1] a movable guide for regulating the position of the sheets loaded on the tray; a plurality of detection electrodes each formed by a pair of electrodes and each disposed at a predetermined position on the tray; a capacitance detection unit that detects the capacitance of each of the plurality of detection electrodes; a control unit that detects the size of the sheet in the moving direction of the guide and the position of the guide based on the capacitance of each of the plurality of detection electrodes detected by the capacitance detection unit; A sheet feeding device comprising:

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