Paper length detection device

Abstract

To provide a sheet length detector capable of detecting a sheet length.SOLUTION: A sheet length detector according to an embodiment comprises a bottom plate, a first regulating unit, a second regulating unit, a magnet, a moving mechanism and an angle sensor. The bottom plate is allowed to rest a paper sheet having a first end side and a second end side opposite to the first end side. The first regulating unit moves relatively to the bottom plate and contacts the first end side, and the second regulating unit contacts the second end side. The magnet rotates in a state S-pole and N-pole parts are parallel with respect to the bottom plate. The moving mechanism supports the magnet and makes the magnet rotate in response to moving the first regulating unit close to or away from the second regulating unit with respect to the bottom plate. The angle sensor faces the magnet so as to output a signal depending on the absolute angle to the magnet.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a paper length detection device. [Background technology]

[0002] Various means have been used to detect the length of paper, such as the paper width, in an image forming apparatus. A known means for detecting the length of paper of a non-standard size is one that uses an encoder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-330068 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a paper length detection device capable of detecting the length of paper. [Means for solving the problem]

[0005] According to an embodiment, the paper length detection device has a bottom plate, a first regulating unit, a second regulating unit, a magnet, a moving mechanism, and an angle sensor. The bottom plate places a paper sheet having a first edge and a second edge opposite the first edge. The first regulating unit moves relative to the bottom plate and contacts the first edge. The second regulating unit contacts the second edge. The magnet rotates with its south pole and north pole parallel to the bottom plate. The moving mechanism supports the magnet and rotates the magnet in response to moving the first regulating unit closer to or farther away from the second regulating unit relative to the bottom plate. The angle sensor faces the magnet. and fixed to the bottom plate. , outputs a signal according to the absolute angle with the magnet and outputting the distance between the first restriction portion and the second restriction portion based on the signal. do. [Brief description of the drawings]

[0006] [Figure 1] 1 is a schematic perspective view showing an image forming apparatus according to an embodiment. [Diagram 2] 1 is a schematic diagram showing an overview of an image forming apparatus according to an embodiment; [Diagram 3] 1 is a schematic block diagram of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 2 is a schematic top view of a paper feed cassette of the image forming apparatus according to the first embodiment. [Diagram 5] 1 is a schematic perspective view showing a part of a paper length detection device of a paper feed cassette of an image forming apparatus according to a first embodiment. [Figure 6] 6 is a schematic perspective view showing the positional relationship between a first rotating body, a first magnet, and a first angle sensor of the paper length detection device shown in FIGS. 4 and 5; FIG. [Figure 7] FIG. 7 is a schematic diagram showing an overview of the first angle sensor shown in FIG. 6. [Figure 8] 7 is a graph showing the relationship between a first angle based on an output signal of a first angle sensor shown in FIG. 6 and a distance between a first restriction portion and a second restriction portion. [Figure 9] 5 is a flowchart of a process for detecting a paper size in the image forming apparatus according to the first embodiment. [Figure 10] FIG. 11 is a schematic block diagram of an image forming apparatus according to a modified example of the first embodiment. [Figure 11] FIG. 11 is a schematic perspective view showing a part of a paper length detection device of a paper feed cassette of an image forming apparatus according to a second embodiment. [Figure 12] FIG. 11 is a schematic top view of a paper feed cassette of an image forming apparatus according to a third embodiment. [Figure 13] FIG. 13 is a schematic block diagram of an image forming apparatus according to a modified example of the third embodiment. [Figure 14] FIG. 13 is a schematic perspective view showing a part of a paper length detection device of a paper feed cassette of an image forming apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment of the paper length detection device 30 of the image forming apparatus 10 will be described with reference to the drawings.

[0008] (First embodiment) An image forming apparatus 10 according to a first embodiment will be described with reference to FIGS. 1 to 9. FIG.

[0009] 1 and 2 is, for example, a multifunction printer (MFP). The image forming apparatus 10 includes a main body 12, a conveying unit 14, a printer 16, an operation panel 18 having a display 181, a scanner 20, a paper feed cassette housing unit 22, and a manual feed tray 24.

[0010] 3, the image forming apparatus 10 further includes a main control unit 26. The transport unit 14, the printer 16, the operation panel 18, the scanner 20, the paper feed cassette housing unit 22, the manual feed tray 24, and the main control unit 26 are provided in the main body 12. The main control unit 26 controls the transport unit 14, the printer 16, the operation panel 18, the scanner 20, the paper feed cassette housing unit 22, and the manual feed tray 24.

[0011] As shown in Figs. 1 and 2, the paper feed cassette storage section 22 has multiple paper feed cassettes 221, 222, 223, and 224 arranged in a vertical direction. Each of the paper feed cassettes 221, 222, 223, and 224 stores, for example, multiple sheets of paper stacked together as paper sheets (medium on which images are formed). The paper sheets are, for example, paper or label paper. The paper sheets may be any type of paper sheets on whose surface an image can be formed. Here, for the sake of simplicity of explanation, it is assumed that the paper sheets P (see the dashed line in Fig. 4) are square or rectangular with four edges Pa, Pb, Pc, and Pd.

[0012] The side where the user inserts and pulls out each of the paper feed cassettes 221, 222, 223, and 224 into and from the paper feed cassette housing unit 22 is referred to as the front side of the image forming apparatus 10. The image forming apparatus 10 is used with each of the paper feed cassettes 221, 222, 223, and 224 housed in the paper feed cassette housing unit 22.

[0013] The paper feed cassettes 221, 222, 223, and 224 each have a paper feed roller 231, 232, 233, and 234. The paper feed rollers 231, 232, 233, and 234 each take out a sheet of paper one by one from the paper feed cassettes 221, 222, 223, and 224. The paper taken out from the paper feed cassettes 221, 222, 223, and 224 is transported to the printer 16 by the transport unit 14.

[0014] The manual feed tray 24 is provided on, for example, the right side surface of the main body 12 when viewed from the front side of the image forming apparatus 10. The manual feed tray 24 has a paper feed roller 241. The paper feed roller 241 takes out sheets of paper one by one from the manual feed tray 24. The sheets taken out from the manual feed tray 24 are transported to the printer 16 by the transport unit 14.

[0015] The conveying unit 14 conveys the paper to the printer 16. The printer 16 forms an image on the paper using a developer such as toner. After the printer 16 forms the image on the paper, the conveying unit 14 conveys the paper to the paper discharge unit 121 of the main body 12.

[0016] The scanner 20 is provided, for example, above the paper discharge unit 121 of the main body 12. The scanner 20 has an automatic document feeder 201 and a document table glass 202. The automatic document feeder 201 is rotatably supported with respect to the main body 12. When the ADF 201 is closed, the ADF 201 covers the entire document reading area on the document table glass 202.

[0017] As shown in FIG. 4, the paper feed cassette housing section 22 and the paper feed cassette 221 have a paper length detection device 30. The paper length detection device 30 has, for example, a box-shaped paper storage section 32 that is open at the top. The paper storage section 32 has a substantially rectangular bottom plate 34 and side plates 361, 362, 363, and 364. The side plates 361, 362, 363, and 364 are provided on the four end sides 341, 342, 343, and 344 of the bottom plate 34, respectively. The side plates 361 and 362 are used as rails when the paper storage section 32 of the paper feed cassette 221 is pulled out from a predetermined position of the main body 12 and stored. The side plate 363 is used as a handle when the user pulls out the paper storage section 32 of the paper feed cassette 221 from a predetermined position of the main body 12 or stores the paper storage section 32 of the paper feed cassette 221 in a predetermined position. When the paper storage unit 32 of the paper feed cassette 221 is stored in a predetermined position in the main body 12, the side plate 364 is disposed on the rear side.

[0018] In this embodiment, an example is taken of a case where a pair of opposing end sides 341, 342 are longer than the remaining pair of end sides 343, 344. The opposing direction between the end sides 341, 342 is defined as a first length direction of the paper feed cassette 221 and paper P. The opposing direction between the end sides 343, 344 is defined as a second length direction of the paper feed cassette 221 and paper P. The relationship in size between the first length direction and the second length direction of the bottom plate 34 may be the same or different, and can be set appropriately. The paper length that can be detected by the paper length detection device 30 of this embodiment is the length in the direction along the first length direction.

[0019] The paper P that can be used in the image forming apparatus 10 of this embodiment is, for example, rectangular and has edges Pa, Pb, Pc, and Pd. The size of the paper P that can be used in the image forming apparatus 10 of this embodiment depends on the specifications of the main body 12, the conveying unit 14, the printer 16, and the paper feed cassette 221 of the image forming apparatus 10. The upper limit of the size of the paper P that can be used in the image forming apparatus 10 of this embodiment may be formed to a size exceeding, for example, A0 size, or the lower limit may be formed to a size below, for example, postcard size, depending on the specifications of the image forming apparatus 10. The fixed size of the paper P refers to standardized sizes such as A size and B size defined by ISO 216 or JIS P 0138. The non-fixed size of the paper P refers to non-standard sizes that are not defined by ISO 216 or JIS P 0138.

[0020] The paper storage section 32 has a positioning section 321 for the paper P on the side of the remaining end side 344 of the four end sides 341, 342, 343, and 344 of the bottom plate 34. The positioning section 321 is formed on the side of the bottom plate 34 opposite to the side plate 363, for example. The positioning section 321 determines the position of the paper P in the second length direction of the bottom plate 34 relative to the bottom plate 34 when the one end side Pd of the paper P abuts against the positioning section 321.

[0021] The size of the bottom plate 34 of the paper storage unit 32 depends on the size of paper P that can be transported by the transport unit 14 of the image forming device 10 and on which an image can be printed by the printer 16. In this embodiment, the size of the bottom plate 34 is formed to be large enough to accommodate, for example, A3 size paper P.

[0022] As shown in FIG. 4 and FIG. 5, the paper length detection device 30 has a first regulating section (paper regulating section) 42 and a second regulating section (paper regulating section) 44. The first regulating section 42 has a regulating surface 421 that regulates a first edge Pa of the paper P. The second regulating section 44 has a regulating surface 441 that regulates a second edge Pb opposite to the first edge Pa of the paper P. The regulating surface 421 of the first regulating section 42 and the regulating surface 441 of the second regulating section 44 face each other and are close to or spaced apart from each other along the first length direction. The distance between the opposing regulating surfaces 421, 441 of the first regulating section 42 and the second regulating section 44 is defined as the distance between the first regulating section 42 and the second regulating section 44.

[0023] The paper length detection device 30 has a first magnet 52 that can rotate with its magnetization direction from the S pole to the N pole parallel to the bottom plate 34. It is preferable to use a permanent magnet as the first magnet 52. In this embodiment, the first magnet 52 is formed in, for example, a disk shape. The first magnet 52 may also be formed in a ring shape, a rectangular parallelepiped shape including a bar shape, or the like.

[0024] The paper length detection device 30 has a first moving mechanism 601 that supports the first magnet 52 and rotates the first magnet 52 in response to the movement of the first regulating portion 42 and the second regulating portion 44 relative to the bottom plate 34. The first moving mechanism 601 converts the linear movement of the first regulating portion 42 and the second regulating portion 44 into a rotation mechanism that rotates the first magnet 52.

[0025] The first moving mechanism 601 has a disk-shaped first rotor 62 that supports the first magnet 52. The first rotor 62 is housed in a substantially circular recess 63 formed in the bottom plate 34. A virtual central axis (rotation axis) Oa of the first rotor 62 extends in a direction perpendicular to the paper surface of the paper P housed in the paper housing unit 32. In this embodiment, the first rotor 62 has a plurality of first meshing teeth (first gear) 621 on its outer circumferential surface. The first rotor 62 is formed, for example, as a pinion with the first meshing teeth 621 as a pinion gear.

[0026] The central axis Oa of the first rotating body 62 preferably coincides with the central axis of the first magnet 52. The central axis Oa of the first magnet 52 and the first rotating body 62 preferably are located at the center of the paper feed cassette 221 in the first length direction.

[0027] The first moving mechanism 601 has a first extending member 72 fixed to the first restricting portion 42 and extending from the first restricting portion 42 toward the second restricting portion 44 along the first length direction. The first extending member 72 is, for example, a long and narrow rectangular plate. The first extending member 72 is housed in a recess 73 formed in the bottom plate 34. The recess 73 is formed between the side plates 361 and 362 parallel to the positioning portion 321. The recess 73 is continuous with the recess 63. The first extending member 72 moves within a predetermined range of the recess 73 while maintaining a parallel state with the positioning portion 321. In this embodiment, the first extending member 72 has a plurality of first teeth (second gears) 721 at the end on the positioning portion 321 side that mesh with the first meshing teeth 621 of the first rotating body 62. The first extension member 72 is formed, for example, as a rack with the first tooth portion 721 as a rack gear. Therefore, the first extension member 72 and the first rotor 62 have a rack-and-pinion relationship.

[0028] In this embodiment, the first moving mechanism 601 has a second extending member 74 fixed to the second restricting portion 44 and extending from the second restricting portion 44 toward the first restricting portion 42 along the first length direction. The second extending member 74 is, for example, a long and narrow rectangular plate. The second extending member 74 is housed in a recess 75 formed in the bottom plate 34. The recess 75 is formed between the side plates 361 and 362 in parallel with the positioning portion 321. The second extending member 74 and the recess 75 are closer to the positioning portion 321 than the first extending member 72 and the recess 73. The recess 75 is continuous with the recess 63. The second extending member 74 moves within a predetermined range while maintaining a state parallel to the positioning portion 321. In this embodiment, the second extension member 74 has a second tooth portion (second gear) 741 that meshes with the first meshing teeth 621 of the first rotating body 62 at the end opposite to the positioning portion 321. The second extension member 74 is formed, for example, as a rack with the second tooth portion 741 as a rack gear. Therefore, the second extension member 74 and the first rotating body 62 have a rack-and-pinion relationship.

[0029] As shown in FIGS. 4 to 6 , the paper length detection device 30 has a first angle sensor 82 at a position facing the first magnet 52. The first angle sensor 82 is preferably provided in the paper feed cassette housing section 22 below the bottom plate 34. The first angle sensor 82 has a substrate 821 and an angle sensor element 822 fixed to the substrate 821 and outputting a signal according to the absolute angle with the first magnet 52. The substrate 821 and the angle sensor element 822 are located directly below the first magnet 52 and spaced apart from the first magnet 52. The substrate 821 is fixed to the paper feed cassette housing section 22.

[0030] As shown in FIG. 3, in this embodiment, the first angle sensor 82 is connected to the main control unit 26 and controlled by the main control unit 26.

[0031] As shown in Fig. 7, the angle sensor element 822 has four magnetic detection elements 841, 842, 843, and 844. Each of these magnetic detection elements 841, 842, 843, and 844 has a magnetic resistance element 85 magnetized in the direction indicated by the arrow in Fig. 7. The magnetization directions of the magnetic resistance elements 85 are perpendicular to each other between the magnetic resistance elements 85. The magnetic detection elements 841, 842, 843, and 844 are, for example, giant magnetoresistance type (GMR type) or tunnel magnetoresistance type (TMR type), which are capable of outputting a magnetic field that changes periodically with the rotation of the first magnet 52 as, for example, an output voltage change.

[0032] If the angle sensor element 822 of the first angle sensor 82 is rectangular, it is preferable that the central axis Oa of the first magnet 52 and the first rotor 62 passes through the center of gravity of the angle sensor element 822. Regardless of whether the first magnet 52 rotates or not, the four magnetic detection elements 841, 842, 843, and 844 output signals (two-phase signals) of sin θ, cos θ, -sin θ, and -cos θ, the phases of which are shifted by ¼ period each. These two-phase signals are input to the main control unit 26 through the board 821.

[0033] 3 amplifies each of the sin θ, cos θ, -sin θ, and -cos θ signals output from the first angle sensor 82 as necessary, A / D converts them, and performs a calculation to obtain arctan (sin / cos), thereby outputting the absolute angle of the first magnet 52. In this embodiment, the first angle sensor 82 outputs a two-phase signal to the main control unit 26. Therefore, the main control unit 26 outputs the absolute angle of less than one rotation (greater than 0° and less than 360°) of the first magnet 52 based on the output signal of the first angle sensor 82.

[0034] In the first moving mechanism 601 of the paper length detection device 30 of this embodiment shown in Figures 4 to 6, it is preferable that the first magnet 52 does not rotate one revolution between the position where the distance between the first and second regulating parts 42, 44 is minimum and the position where it is maximum. For example, when the distance between the first and second regulating parts 42, 44 is minimum, the magnetization direction of the first magnet 52, i.e., the direction in which the N pole faces, is set to a direction of 0° with respect to the central axis Oa of the first magnet 52 and the first rotating body 62. For example, when the distance between the first and second regulating parts 42, 44 is maximum, the magnetization direction of the first magnet 52 is set to an angle of less than 360°, for example, 350° (<360°), with respect to the central axis Oa of the first magnet 52 and the first rotating body 62. In the following description, it is assumed that when the distance between the first and second restricting portions 42, 44 is at a maximum, the absolute angle of the first magnet 52 is 350°.

[0035] In paper length detection device 30, first magnet 52 is installed on bottom plate 34 so that when the distance between first regulating portion 42 and second regulating portion 44 is minimum, the output from first angle sensor 82 causes main control portion 26 to output the absolute angle of first magnet 52 as 0°. Similarly, in paper length detection device 30, first magnet 52 is installed on bottom plate 34 so that when the distance between first regulating portion 42 and second regulating portion 44 is maximum, the output from first angle sensor 82 causes main control portion 26 to output the absolute angle of first magnet 52 as 350°.

[0036] 3, the image forming apparatus 10 has an angle / length table 90. The angle / length table 90 is controlled by the main control unit 26. The angle / length table 90 is formed as a storage unit that stores information on the distance between the first regulating unit 42 and the second regulating unit 44 corresponding to the absolute angle of the first magnet 52. Note that the angle / length table 90 stores information on the distance between the first regulating unit 42 and the second regulating unit 44 in increments of, for example, 0.5° or 1° within a range in which the absolute angle of the first magnet 52 is between 0° and 350° (<360°).

[0037] Fig. 8 shows an example of the relationship in this embodiment between the absolute angle of the first magnet 52 output by the main control unit 26 based on the signal output by the first angle sensor 82 and the distance between the first restricting portion 42 and the second restricting portion 44. In the example shown in Fig. 8, when the absolute angle of the first magnet 52 is 0°, the distance between the first restricting portion 42 and the second restricting portion 44 is about 30 mm. When the absolute angle of the first magnet 52 is 350°, the distance between the first restricting portion 42 and the second restricting portion 44 is about 300 mm.

[0038] The relationship between the absolute angle of the first magnet 52 and the distance between the first and second restricting portions 42 and 44 is changed depending on the size of the paper to be detected. For example, if the distance between the first and second restricting portions 42 and 44 is 841 mm (A0 size), and the absolute angle of the first magnet 52 is, for example, 350°, the distance between the first and second restricting portions 42 and 44 is approximately 841 mm. Therefore, the diameter of the first rotating body 62 and the number of teeth of the first meshing teeth 621 can be changed depending on the size of the paper to be detected. In addition, the distance between the first extending member 72 and the second extending member 74 can be changed depending on the size of the paper to be detected. The number of teeth of the first tooth portion 721 of the first extending member 72 and the second tooth portion 741 of the second extending member 74 can be changed depending on the size of the paper to be detected.

[0039] Next, the operation of the paper length detection device 30 of the image forming apparatus 10 will be described.

[0040] A user of the image forming apparatus 10 moves the first restricting portion 42 and the second restricting portion 44, for example, in a state in which the paper feed cassette 221 is pulled out from the paper feed cassette housing portion 22. The first tooth portion 721, which is a rack gear, moves in the first length direction of the paper feed cassette 221 along the recess 73, and the second tooth portion 741, which is a rack gear, moves in the first length direction of the paper feed cassette 221 along the recess 75. At this time, the first meshing teeth 621, which is a pinion gear of the first rotating body 62, rotates in conjunction with the first tooth portion 721 and the second tooth portion 741.

[0041] As the user moves the first restricting portion 42 and the second restricting portion 44 in a direction approaching each other along the first length direction, the first extending member 72 and the second extending member 74 move along the recesses 73 and 75. The movement of the first extending member 72 and the second extending member 74 along the recesses 73 and 75 causes the first rotating body 62 to rotate in a first direction α with respect to the central axis Oa. Therefore, the first magnet 52 supported by the first rotating body 62 rotates in the first direction α in accordance with the rotation of the first rotating body 62 in the first direction α.

[0042] In response to the user moving the first restricting portion 42 and the second restricting portion 44 in a separation direction in which they are separated from each other along the first length direction, the first rotating body 62 rotates in the second direction β with respect to the central axis Oa. Therefore, the first magnet 52 supported by the first rotating body 62 rotates in the second direction β in association with the rotation of the first rotating body 62 in the second direction β. Therefore, as the first extending member 72 and the second extending member 74 move along the recesses 73, 75, the first rotating body 62 and the first magnet 52 rotate.

[0043] When the user moves the first restricting portion 42 or the second restricting portion 44 in the first length direction, the first moving mechanism 601 moves the first extending member 72 and the second extending member 74 in conjunction with each other. When the first extending member 72 moves the first restricting portion 42 relative to the bottom plate 34, the first extending member 72 rotates the first rotating body 62 and the first magnet 52 by a rotation angle corresponding to the movement distance of the first restricting portion 42. When the second extending member 74 moves the second restricting portion 42 relative to the bottom plate 34, the second extending member 74 rotates the first rotating body 62 and the first magnet 52 by a rotation angle corresponding to the movement distance of the second restricting portion 44.

[0044] A paper length detection method for outputting the length (paper width or paper length) along the first length direction of a certain paper P using paper length detection device 30 of image forming apparatus 10 will be described with reference to Fig. 9. Here, it is assumed that paper feed cassette 221 is stored in paper feed cassette storage unit 22.

[0045] For example, when a user switches on the power of the image forming apparatus 10, the main control unit 26 acquires a signal output from the first angle sensor 82 (ACT1).

[0046] The main control unit 26 calculates the absolute angle of the first magnet 52 with respect to the first angle sensor 82 based on the signal obtained from the first angle sensor 82 (ACT2).

[0047] The main control unit 26 refers to the angle / length table 90 and obtains information on the distance corresponding to the absolute angle of the first magnet 52 (ACT3).

[0048] Then, the main control unit 26 outputs information on the distance between the first restriction portion 42 and the second restriction portion 44 with respect to the absolute angle of the first magnet 52 based on the information stored in the angle / length table 90 (ACT4). The main control unit 26 displays information on the distance between the restriction surface 421 of the first restriction portion 42 and the restriction surface 441 of the second restriction portion 44 on the display 181, for example.

[0049] Here, when one end side Pa of a certain sheet of paper P contacts the restricting surface 421 of the first restricting portion 42 and the other end side Pb contacts the restricting surface 441 of the second restricting portion 44, the distance between the first restricting portion 42 and the second restricting portion 44 matches the length in the first length direction of the certain sheet of paper P. Therefore, information on the distance between the first restricting portion 42 and the second restricting portion 44 can be the sheet width or sheet length when one end side Pa of a certain sheet of paper P contacts the restricting surface 421 of the first restricting portion 42 and the other end side Pb contacts the restricting surface 441 of the second restricting portion 44.

[0050] The main control unit 26 may display information on the display 181 as the distance between the first regulating unit 42 and the second regulating unit 44, or may display information on the display 181 as the paper width. When printing image data on a certain paper P, the main control unit 26 adjusts the magnification of the image data according to the information on the paper width or paper length. The main control unit 26 can use the information on the paper width or paper length of a certain paper P when controlling to print image data within the range of the paper P, for example.

[0051] For example, the user pulls out the paper feed cassette 221 from the main body 12 and manually changes the distance between the first regulating unit 42 and the second regulating unit 44. Then, the user stores the paper feed cassette 221 in the main body 12. After the user stores the paper feed cassette 221 in the paper feed cassette storage unit 22, the main control unit 26 determines whether the output signal of the absolute angle of the first magnet 52 relative to the first angle sensor 82 has changed (ACT5). If the output signal of the absolute angle of the first magnet 52 relative to the first angle sensor 82 has changed, the main control unit 26 returns to ACT2 again, passes through ACT3, and outputs a new distance in ACT4.

[0052] If the output signal of the absolute angle of the first magnet 52 relative to the first angle sensor 82 has not changed, an output is made as to whether the power of the image forming apparatus 10 has been turned off (ACT6). If the power has been turned off, the process ends. If the power has not been turned off and is still on, the main control unit 26 performs the process of ACT4 again.

[0053] In this way, the paper length detection device 30 outputs the distance between the first regulating portion 42 and the second regulating portion 44 as a signal related to an angle. Then, the image forming apparatus 10 having the paper length detection device 30 outputs the distance between the first regulating portion 42 and the second regulating portion 44. Therefore, the image forming apparatus 10 outputs the distance between the first regulating portion 42 and the second regulating portion 44 as the length in the first length direction.

[0054] According to this embodiment, the paper length detection device 30 can output a signal related to the absolute angle of the first magnet 52 from the first angle sensor 82. For example, after the first regulating unit 42 and the second regulating unit 44 are manually operated while the power of the image forming apparatus 10 is OFF, the first angle sensor 82 of the paper length detection device 30 outputs a signal related to the absolute angle of the first magnet 52 to the main control unit 26 after the power of the image forming apparatus 10 is switched ON. Therefore, even if the image forming apparatus 10 is once changed to a power OFF state, it can output the distance between the first regulating unit 42 and the second regulating unit 44 when the power is ON.

[0055] The angle-related signal output by the paper length detection device 30 depends on the absolute angle of the first magnet 52 relative to the first angle sensor 82. For this reason, the distance along the first length direction between the first regulating portion 42 and the second regulating portion 44 does not depend on whether the paper P is a standard size or an irregular size.

[0056] The first magnet 52 and the first angle sensor 82 are separated from each other and are not in contact with each other. Therefore, the life of the first angle sensor 82 does not affect the sliding between the first extending member 72 and the recessed portion 73 and the sliding between the second extending member 74 and the recessed portion 75 that accompanies the movement of the first restricting portion 42 and the second restricting portion 44.

[0057] In this embodiment, the linear movement of the first restricting portion 42 or the second restricting portion 44 can be converted into the rotational movement of the first rotating body 62. The first rotating body 62 has, for example, the first meshing teeth 621, the first extending member 72 has, for example, the first tooth portion 721 at its end, and the second extending member 74 has, for example, the second tooth portion 741 at its end. The first extending member 72 moves without slipping between its end face and the outer circumferential surface of the first rotating body 62, and between its end face and the outer circumferential surface of the first rotating body 62. Therefore, the absolute angle of the first magnet 52 maintains the state shown in FIG. 8 with respect to the distance associated with the movement between the first restricting portion 42 and the second restricting portion 44. Therefore, the first angle sensor 82 outputs a signal related to the absolute angle of the first magnet 52, and the main control unit 26 can output the distance between the first restricting portion 42 and the second restricting portion 44. If the end face of the first extending member 72 moves without slipping between the outer circumferential surface of the first rotating body 62, the first meshing teeth 621 and the first teeth 721 may be omitted. If the end face of the second extending member 74 moves without slipping between the outer circumferential surface of the first rotating body 62, the first meshing teeth 621 and the second teeth 741 may be omitted. For this reason, the first moving mechanism 601 may be configured to rotate the first rotating body 62 and the first magnet 52 in accordance with the distance between the first restricting portion 42 and the second restricting portion 44.

[0058] In the present embodiment, an example has been described in which the main control unit 26 outputs the distance between the first restriction unit 42 and the second restriction unit 44 from the angle / length table 90 based on the output of the absolute angle of the first magnet 52 from the first angle sensor 82. If the graph shown in FIG. 8 is made into an equation and the equation is stored in the storage unit that has formed it into the angle / length table 90, the main control unit 26 can output the distance between the first restriction unit 42 and the second restriction unit 44 by substituting the output of the absolute angle of the first magnet 52 from the first angle sensor 82 into the equation.

[0059] In the present embodiment, an example has been described in which the first angle sensor 82 outputs a two-phase signal related to an absolute angle of 0° or more and less than 360°. For example, the first angle sensor 82 may have two magnetic detection elements 841, 842 and be configured to output a one-phase signal related to an absolute angle of 0° or more and less than 180°, i.e., less than half a rotation. In this case, the angle / length table 90 stores a distance corresponding to an angle of 0° or more and less than 180°. The main control unit 26 can then output a distance according to the output signal of the first angle sensor 82 for an absolute angle of 0° or more and less than 180°.

[0060] In the present embodiment, the paper feed cassette housing section 22 and the paper feed cassette 221 have been described as having the paper length detection device 30. It is also preferable that the paper feed cassette housing section 22 and the other paper feed cassettes 222, 223, and 224 each have the paper length detection device 30. It is also preferable that the manual feed tray 24 has the paper length detection device 30. In addition, in the present embodiment, an example in which the first angle sensor 82 is provided in the paper feed cassette housing section 22 has been described. The first angle sensor 82 may be fixed to the bottom plate 34 of the paper feed cassette 221. In this case, the first angle sensor 82 is connected to the main control section 26 when the paper feed cassette 221 is housed in the paper feed cassette housing section 22, and is disconnected from the main control section 26 when the paper feed cassette 221 is removed from the paper feed cassette housing section 22.

[0061] The first moving mechanism 601 of the paper length detection device 30 can be modified in various ways as long as it is configured to rotate the first magnet 52 in response to moving the first regulating portion 42 and the second regulating portion 44 closer to or farther apart.

[0062] In the paper length detection device 30 according to the present embodiment, both the first regulating unit 42 and the second regulating unit 44 move in conjunction with each other. In the paper length detection device 30, one of the first regulating unit 42 and the second regulating unit 44 may be configured to move. For example, the regulating surface 441 of the second regulating unit 44 may be formed as a positioning unit similar to the positioning unit 321. In this case, the first rotating body 62 and the first magnet 52 may be disposed on the edge side 342 side of the bottom plate 34 rather than the center of the first length direction of the paper feed cassette 221. For this reason, the paper length detection device 30 may include at least one of the first regulating unit 42 and the second regulating unit 44. In addition, the first moving mechanism 601 may be configured to rotate the first magnet 52 in response to, for example, moving the first regulating unit 42 relative to the bottom plate 34.

[0063] Therefore, according to this embodiment, it is possible to provide a paper length detection device 30 capable of detecting the size of paper.

[0064] (Modification of the first embodiment) In the first embodiment, an example has been described in which the signal from the first angle sensor 82 is calculated by the main control unit 26 to output the absolute angle of the first magnet 52. As shown in FIG. 10, the first angle sensor 82 of the paper length detection device 30 preferably includes, in addition to the substrate 821 and the angle sensor element 822, an angle / length table 90 and a control unit 100 that outputs the paper length stored in the angle / length table 90 based on the signal from the angle sensor element 822. The angle / length table 90 and the control unit 100 are provided on the substrate 821, for example. In this case, the first angle sensor 82 is formed as an IC chip that includes the angle / length table 90 and the control unit 100. The control unit 100 outputs the absolute angle of the first magnet 52 and the distance between the first regulating unit 42 and the second regulating unit 44 corresponding to the absolute angle of the first magnet 52 based on the output signal from the angle sensor element 822.

[0065] Therefore, the paper length detection device 30 can output the distance between the first regulating unit 42 and the second regulating unit 44 without using the main control unit 26. The paper length detection device 30 can display the distance between the first regulating unit 42 and the second regulating unit 44 on the display 181, for example, using the main control unit 26 connected to the control unit 100.

[0066] According to this modification, it is possible to provide a paper length detection device 30 capable of detecting the size of paper.

[0067] Second embodiment A second embodiment of the image forming apparatus 10 will be described with reference to Fig. 11. In the second embodiment, the description of matters common to the first embodiment (including the modified examples) will be omitted where appropriate.

[0068] Fig. 11 is a schematic diagram showing a part of the paper length detection device 30. The positional relationship between the first regulating portion 42, the second regulating portion 44, the first extending member 72, and the second extending member 74 shown in Fig. 11 is the same as the example shown in Fig. 5 of the first embodiment.

[0069] The first moving mechanism 601 of the paper length detection device 30 has a first rotating body 62, a second rotating body 64, a first extending member 72, and a second extending member 74. As shown in FIG. 11, the first rotating body 62, the second rotating body 64, the first extending member 72, and the second extending member 74 of the paper length detection device 30 are placed on the bottom plate 34. The first rotating body 62, the first extending member 72, and the second extending member 74 are preferably disposed in a recess formed in the bottom plate 34, similar to the recesses 63, 73, and 75 described in the first embodiment. The second rotating body 64 is also preferably disposed in a recess formed in the bottom plate 34.

[0070] In this embodiment, the first rotating body 62 supporting the first magnet 52 is not positioned between the first extension member 72 and the second extension member 74, but is positioned closer to the positioning portion 321 than the second extension member 74.

[0071] The second extension member 74 has a plurality of third teeth 742 on the opposite side to the second teeth 741 in addition to the second teeth 741 described in the first embodiment. The third teeth 742 of the second extension member 74 mesh with the first meshing teeth 621 of the first rotating body 62 when the second regulating portion 44 is moved relative to the bottom plate 34. The second extension member 74 is formed, for example, as a rack with the third teeth 741 as a rack gear. The first rotating body 62 is formed, for example, as a pinion with the first meshing teeth 621 as a pinion gear. Therefore, in this embodiment, the second extension member 74 and the first rotating body 62 are in a rack-and-pinion relationship.

[0072] The second rotor 64 is formed in a disk shape with a smaller diameter than the first rotor 62. The virtual central axis (rotation axis) Ob of the second rotor 64 extends in a direction perpendicular to the paper stored in the paper storage unit 32. The second rotor 64 has second meshing teeth 641 on the outer circumferential surface of the second rotor 64. The second meshing teeth 641 mesh with both the first toothed portion 721 of the first extension member 72 and the second toothed portion 741 of the second extension member 74. The second rotor 64 is formed as a pinion with the second meshing teeth 641 as a pinion gear.

[0073] In the movable range of the first restricting portion 42 and the second restricting portion 44, the second rotating body 64 rotates more than one rotation (360°). In the movable range of the first restricting portion 42 and the second restricting portion 44, the rotation angle of the first magnet 52 and the first rotating body 62 does not exceed one rotation. Therefore, the first angle sensor 82 directly below the first magnet 52 and the first rotating body 62 outputs a signal related to the absolute angle of the first magnet 52 to the main control portion 26.

[0074] The second rotor 64 has a smaller diameter than the first rotor 62. If the first meshing teeth 621 of the first rotor 62 and the second meshing teeth 641 of the second rotor 64 have the same number of teeth, using the second rotor 64 between the first extension member 72 and the second extension member 74 allows the first regulating portion 42 and the second regulating portion 44 to move more smoothly than using the first rotor 62.

[0075] Incidentally, the operation of the image forming apparatus 10 including the paper length detection device 30 has been described in the first embodiment, and therefore will not be described here.

[0076] According to this embodiment, it is possible to provide a paper length detection device 30 capable of detecting the paper length.

[0077] Third embodiment A third embodiment of the image forming apparatus 10 will be described with reference to Fig. 12 and Fig. 13. In the third embodiment, the description of matters common to the first embodiment (including the modified examples) and the second embodiment will be omitted.

[0078] 12, paper length detection device 30 has a third restriction unit (paper restriction unit) 46 that restricts a third edge of the paper. Paper length detection device 30 has a second movement mechanism 602 that supports a second magnet 54 and rotates the second magnet 54 in response to movement of the third restriction unit 46 relative to the bottom plate 34. The third restriction unit 46 is movable by the second movement mechanism 602 along the second length direction in a direction approaching and moving away from positioning unit 321.

[0079] The second moving mechanism 602 has a disk-shaped third rotor 66 that supports the second magnet 54. The third rotor 66 is housed in a substantially circular recess 67 formed in the bottom plate 34. A virtual central axis (rotation axis) Oc of the third rotor 66 extends in a direction perpendicular to the paper stored in the paper storage unit 32. The third rotor 66 has a plurality of third meshing teeth 661 on its outer circumferential surface. The third rotor 66 is formed as a pinion with the third meshing teeth 661 as a pinion gear.

[0080] The second moving mechanism 602 has a third extending member 76 fixed to the third restricting portion 46 and extending from the third restricting portion 46 toward the positioning portion 321 along the second length direction. The third extending member 76 is, for example, a long and narrow rectangular plate. The third extending member 76 is housed in a recess 77 formed in the bottom plate 34. The recess 77 is formed between the side plate 363 and the positioning portion 321. The third extending member 76 and the recess 77 extend in a direction perpendicular to the moving direction of the first restricting portion 42 and the second restricting portion 44. The recess 77 communicates with the recess 67. The third extending member 76 moves within a predetermined range while maintaining a state parallel to the side plates 361 and 362. The third extending member 76 has, for example, a fourth tooth portion 761 at the end portion on the side plate 361 side that meshes with the third meshing tooth 661 of the third rotating body 66. The third extension member 76 is formed as a rack with the fourth tooth portion 761 as a rack gear.

[0081] A contact state is maintained between the third meshing teeth 661 of the third rotating body 66 and the fourth tooth portion 761 of the third extending member 76. The second moving mechanism 602 moves the third extending member 76 along the recessed portion 77 in response to moving the third restricting portion 46 in an approaching direction to approach the positioning portion 321. The third extending member 76 and the third rotating body 66 have a rack-and-pinion relationship.

[0082] It should be noted that the third extension member 76 shown in FIG. 12 is configured to pass under the first extension member 72, for example.

[0083] The second moving mechanism 602 rotates the third rotating body 66 in a first direction α with respect to the central axis Oc in response to the movement of the third restricting portion 46 in a proximity direction to the positioning portion 321 along the second length direction. Therefore, the second magnet 54 supported by the third rotating body 66 rotates in the first direction α with the rotation of the third rotating body 66 in the first direction α. ​​The second moving mechanism 602 rotates the third rotating body 66 in a second direction β with respect to the central axis Oc in response to the movement of the third restricting portion 46 in a separation direction to move away from the positioning portion 321 along the second length direction. Therefore, the second magnet 52 supported by the third rotating body 66 rotates in the second direction β with the rotation of the third rotating body 66 in the second direction β. Therefore, as the third extending member 76 moves along the recessed portion 77, the third rotating body 66 and the second magnet 54 rotate. The central axis Oc of the second magnet 54 and the third rotating body 66 does not move. The central axis Oc of the second magnet 54 and the third rotating body 66 is located, for example, at the center of the first length direction of the paper feed cassette 221.

[0084] The paper length detection device 30 has a second angle sensor 86 at a position facing the second magnet 54, which outputs a signal according to the absolute angle with respect to the second magnet 54. The second angle sensor 86 is preferably provided in the paper feed cassette storage section 22 below the bottom plate 34.

[0085] 13, the second angle sensor 86 is connected to, for example, the main control unit 26 and is controlled by the main control unit 26. The second angle sensor 86 is configured similarly to the first angle sensor 82. That is, the second angle sensor 86 outputs signals (two-phase signals) of sin θ, cos θ, -sin θ, and -cos θ, the phases of which are shifted by ¼ period, regardless of whether the second magnet 54 rotates or not.

[0086] In this embodiment, when the width between the third restricting portion 46 and the positioning portion 321 is at a minimum, the direction in which the N pole of the second magnet 54 faces is set to a direction of 0° with respect to the central axis Oc of the second magnet 54 and the third rotating body 66. For this reason, the main control portion 26 outputs an absolute angle of less than one rotation (greater than 0° and less than 360°) of the third rotating body 66 supporting the second magnet 54, based on a signal output from the second angle sensor 86.

[0087] 8, a length according to the absolute angle of the second magnet 54 is specified according to the output of the absolute angle of the second magnet 54 by the second angle sensor 86. This information is stored in an angle / length table 90. Therefore, the main control unit 26 outputs the length of the paper based on the information stored in the angle / length table 90.

[0088] The paper length detection device 30 according to the present embodiment described above includes the bottom plate 34, the third regulating unit 46, the positioning unit 321 as the regulating unit, the second magnet 54, the second moving mechanism 602, and the second angle sensor 86. The second moving mechanism 602 supports the second magnet 54 and rotates the second magnet 54 in response to the movement of the third regulating unit 46 relative to the bottom plate 34. The second angle sensor 86 faces the second magnet 54 and outputs a signal according to the absolute angle with the second magnet 54. Such a paper length detection device 30 outputs the paper length in the second length direction between the regulating surface 461 of the third regulating unit 46 and the positioning unit 321 as a signal related to the angle. Then, the image forming apparatus 10 having the paper length detection device 30 outputs the distance between the third regulating unit 46 and the positioning unit 321.

[0089] The paper length detection device 30 according to this embodiment can detect both the length along the first length direction and the length along the second length direction of the paper P. Therefore, according to this embodiment, it is possible to provide a paper length detection device 30 that can detect the paper length.

[0090] In addition, the central axis Oc of the second magnet 54 and the third rotating body 66 may be located, for example, on the end side 341 or end side 342 of the bottom plate 34 rather than at the center of the first longitudinal direction of the paper feed cassette 221.

[0091] (Fourth embodiment) A fourth embodiment of the image forming apparatus 10 will be described with reference to Fig. 14. In the fourth embodiment, the description of matters common to the first embodiment (including the modified examples) to the third embodiment will be omitted.

[0092] The paper length detection device 30 shown in Fig. 14 has the same configuration as the first regulating unit 42, the second regulating unit 44, the second rotating body 64 of the first moving mechanism 601, the first extending member 72, and the second extending member 74 shown in Fig. 11. Also, the paper length detection device 30 shown in Fig. 14 has the same configuration as the third regulating unit 46, the third rotating body 66 of the second moving mechanism 602, and the third extending member 76 shown in Fig. 12.

[0093] 14 restricts the end face of the paper sheet with the first restricting unit 42 and the second restricting unit 44, and measures the paper sheet length by moving the third restricting unit 46 closer to or away from the positioning unit 321. The example shown in FIG 14 is an example that does not use the first magnet 52, the first rotating body 62, and the first angle sensor 82.

[0094] The paper length detection device 30 according to this embodiment can detect the paper length. Therefore, according to this embodiment, it is possible to provide a paper length detection device 30 that can detect the paper length.

[0095] According to at least one of the embodiments described above, it is possible to provide a paper length detection device 30 capable of detecting the paper length.

[0096] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. The following is a summary of the claims of this application as filed. [Appendix 1] a bottom plate on which paper sheets are placed, the bottom plate having a first end side and a second end side opposite to the first end side; a first restriction portion that moves relative to the bottom plate and contacts the first end side; a second restriction portion contacting the second end side; A magnet that rotates with its south pole and north pole parallel to the bottom plate; a moving mechanism that supports the magnet and rotates the magnet in response to moving the first regulating portion closer to or farther from the second regulating portion with respect to the bottom plate; an angle sensor that faces the magnet and outputs a signal according to an absolute angle with the magnet; A paper length detection device having the following. [Appendix 2] A control unit that outputs the absolute angle based on the signal; a storage unit that stores a distance between the first restriction portion and the second restriction portion according to the absolute angle being equal to or greater than 0° and less than 360°, or equal to or greater than 0° and less than 180°; Equipped with 2. The paper length detection device according to claim 1, wherein the control unit outputs the distance from the memory unit in accordance with the absolute angle. [Appendix 3] The moving mechanism includes: A disk-shaped first rotor that supports the magnet; a first extending member that is fixed to the first regulating portion, extends from the first regulating portion to an outer circumferential surface of the first rotating body, and rotates the first rotating body by a rotation angle corresponding to a moving distance of the first regulating portion when the first regulating portion is moved relative to the bottom plate; 3. The paper length detection device according to claim 1, further comprising: [Appendix 4] the outer circumferential surface of the first rotor is provided with a first gear; 4. The paper length detection device according to claim 3, wherein the first extension member includes a second gear that meshes with the first gear. [Appendix 5] The second restricting portion is movable relative to the bottom plate, The moving mechanism includes: a second rotor having a disk shape with a smaller diameter than the first rotor and an outer circumferential surface that contacts an end of the first extension member opposite to the first rotor; a second extension member that is fixed to the second regulating portion, extends between the second regulating portion and the outer circumferential surface of the second rotating body, and rotates the second rotating body and the first rotating body by a rotation angle corresponding to a moving distance of the second regulating portion when the second regulating portion is moved relative to the bottom plate; 5. The paper length detection device according to claim 3 or 4, [Explanation of symbols]

[0097] 10...image forming apparatus, 22...paper feed cassette housing section, 221, 222, 223, 224...paper feed cassette, 231, 232, 233, 234...paper feed roller, 24...manual feed tray, 241...paper feed roller, 26...main control section, 30...paper length detection device, 32...paper housing section, 321...positioning section, 34...bottom plate, 341, 342, 343, 344...edge, 361, 362, 363...side plate, 42...first regulation section, 421...regulation surface, 44...second regulation Control portion, 441...regulating surface, 52...first magnet, 601...first moving mechanism, 62...first rotating body, 621...first meshing tooth, 63...recess, 72...first extension member, 721...first tooth portion, 73...recess, 74...second extension member, 741...second tooth portion, 75...recess, 82...first angle sensor, 821...substrate, 822...angle sensor element, 841, 842, 843, 844...magnetic detection elements, 85...magnetic resistance element, 90...angle / length table

Claims

1. a bottom plate on which a sheet of paper is placed, the bottom plate having a first end side and a second end side opposite to the first end side; a first restriction portion that moves relative to the bottom plate and contacts the first end side; a second restriction portion contacting the second end side; a magnet that rotates with its south pole and north pole parallel to the bottom plate; a moving mechanism that supports the magnet and rotates the magnet in response to moving the first restricting portion closer to or farther from the second restricting portion with respect to the bottom plate; an angle sensor that is fixed to the bottom plate facing the magnet, outputs a signal according to an absolute angle with respect to the magnet, and outputs a distance between the first restriction portion and the second restriction portion based on the signal; A paper length detection device having the following.

2. A control unit that outputs the absolute angle based on the signal; a storage unit that stores a distance between the first restriction portion and the second restriction portion according to an absolute angle of 0° or more and less than 360°, or an absolute angle of 0° or more and less than 180°; Equipped with The paper length detection device according to claim 1 , wherein the control unit outputs the distance from the storage unit in accordance with the absolute angle.

3. The moving mechanism includes: A first rotating body having a disk shape that supports the magnet; a first extending member that is fixed to the first regulating portion, extends from the first regulating portion to an outer circumferential surface of the first rotating body, and rotates the first rotating body by a rotation angle corresponding to a moving distance of the first regulating portion when the first regulating portion is moved relative to the bottom plate; The sheet length detection device according to claim 1 or 2, further comprising:

4. The outer circumferential surface of the first rotor includes a first gear, The paper length detection device according to claim 3 , wherein the first extension member includes a second gear that meshes with the first gear.

5. The second restricting portion is movable with respect to the bottom plate, The moving mechanism includes: a second rotor having a disk shape with a smaller diameter than the first rotor and an outer circumferential surface that contacts an end of the first extension member opposite to the first rotor; a second extending member that is fixed to the second regulating portion, extends between the second regulating portion and the outer circumferential surface of the second rotating body, and rotates the second rotating body and the first rotating body by a rotation angle corresponding to a moving distance of the second regulating portion when the second regulating portion is moved relative to the bottom plate; The sheet length detection device according to claim 3 or 4, further comprising:

Images