Detection device

Abstract

To detect a front end and a rear end in a medium during conveyance, and to accurately detect positions of both ends of a medium in a direction perpendicular to a conveyance direction of the medium during the conveyance, compared to the case where a length of the medium in the direction perpendicular to the conveyance direction is estimated on the basis of a length of the medium in the conveyance direction.SOLUTION: A detection device includes: a first detection part for detecting a front end and a rear end in a medium during conveyance; and a second detection part for detecting both ends in a perpendicular direction perpendicular to the conveyance direction in the medium detected by the first detection part during the conveyance.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Patent document 1 discloses an image forming device that has an image forming section for forming images, a paper inversion section for double-sided printing, a guide means for maintaining the position of the paper in the paper inversion section, and a paper position maintaining means that, when paper is transported whose length in the paper transport direction is longer than the length of the transport path within the paper inversion section, continues to maintain the position of the paper using the guide means from the point when the entire paper is contained in the transport path, the transport operation stops, and the rear end of the paper reaches the inversion start position, and ends the maintenance and releases the paper when the next image forming operation becomes possible.

[0003] Patent document 2 discloses a sheet length measuring device having a rotating body that rotates in contact with a sheet material, a measurement mechanism that measures the amount of rotation of the rotating body, and a position detection mechanism that is provided upstream and downstream of the rotating body in the conveying direction of the sheet material, wherein the position detection mechanism has a detection member row in which multiple detection members are arranged, and the position detection mechanism is arranged across the side edges of the sheet material in the width direction and is arranged at an angle with respect to the conveying direction of the sheet material, and the sheet length of the sheet material is measured based on the amount of rotation of the rotating body measured by the measurement mechanism and the end position of the sheet material detected by the position detection mechanism. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4133702 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-114659 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to enable accurate detection of the positions of both ends of a medium in a direction perpendicular to the transport direction while the medium is being transported, compared to detecting the leading and trailing ends of the medium while it is being transported and estimating the length of the medium in a direction perpendicular to the transport direction based on the length of the medium in the transport direction. [Means for solving the problem]

[0006] The first aspect includes a first detection unit that detects the leading and trailing ends of a medium being transported, and a second detection unit that detects both ends of the medium in a direction perpendicular to the transport direction of the medium being transported and detected by the first detection unit.

[0007] The second aspect comprises a conveying section that conveys the medium, and a bumping section that is provided downstream in the conveying direction from the conveying section and against which the front end of the medium conveyed by the conveying section bumps, and the second detection section is provided downstream in the conveying direction from the bumping section.

[0008] In a third aspect, the second detection unit is divided into a portion that detects one end of the medium in the orthogonal direction and a portion that detects the other end, and is arranged to face each other in the orthogonal direction.

[0009] In a fourth aspect, at least one of the detection sections of the second detection section that is divided and arranged in the orthogonal direction detects the amount of positional deviation in the orthogonal direction on the medium.

[0010] In a fifth aspect, the medium conveying device includes an abutment portion against which the leading edge of the medium abuts, and the first detection portion is provided upstream of the abutment portion in the transport direction.

[0011] In a sixth aspect, the first detection unit includes a leading end detection unit that detects the leading end of the medium being transported, and a trailing end detection unit that has a plurality of detection elements arranged along the transport direction and detects the trailing end of the medium being transported, wherein the distance between the detection element arranged at the most upstream side in the transport direction and the leading end detection unit is shorter than the transport direction length of the largest size medium.

[0012] In the seventh aspect, two sets of the front end detection portion and the rear end detection portion are arranged so as to overlap each other when viewed in the conveying direction.

[0013] In the eighth aspect, the conveying section conveys the medium at a constant speed and at a conveying speed slower than the conveying speed upstream of the leading end detection section in the conveying direction, and each of the leading end detection section and the trailing end detection section detects the leading end and trailing end of the medium while it is being conveyed by the conveying section.

[0014] In a ninth aspect, the medium conveying unit is movable between a clamping position where the medium is clamped and a spaced position where the medium is spaced apart, and conveys the medium when positioned at the clamping position.The upstream conveying unit is arranged upstream in the conveying direction relative to the conveying unit, and each of the leading end detection unit and the trailing end detection unit detects the leading end and trailing end of the medium when the upstream conveying unit is positioned at the spaced position. [Effects of the Invention]

[0015] According to the configuration of the first aspect, the positions of both ends of a medium in a direction perpendicular to the transport direction of the medium can be detected with high accuracy while the medium is being transported.

[0016] According to the configuration of the second aspect,

[0017] The accuracy of detection of both ends of the medium by the second detection unit is improved compared to when the second detection unit is provided upstream of the abutment unit in the transport direction.

[0018] According to the configuration of the third aspect, it is possible to avoid placing the detection unit in areas that are not necessary for detecting both ends of the medium in the perpendicular direction, compared to when the second detection unit is not divided and is composed of a single detection unit extending from one end side to the other end side of the medium in the perpendicular direction.

[0019] According to the configuration of the fourth aspect,

[0020] The number of parts can be reduced compared to when a detection unit that detects the amount of positional deviation in the orthogonal direction of the medium is provided separately from the second detection unit.

[0021] According to the configuration of the fifth aspect, compared to when the first detection unit is provided downstream in the transport direction from the abutment unit, the influence on the medium whose orientation has been adjusted by the abutment unit when it is detected by the first detection unit can be reduced.

[0022] According to the configuration of the sixth aspect, the detection device can be made smaller in length in the transport direction than when the distance between the detection element located at the most upstream side in the transport direction of the trailing end detection unit and the leading end detection unit is longer than the transport direction length of the largest size medium.

[0023] According to the configuration of the seventh aspect, the detection accuracy of the leading and trailing edges of the medium is higher than when a pair of leading and trailing edge detection units are arranged so that they overlap when viewed in the transport direction.

[0024] According to the configuration of the eighth aspect, the detection accuracy of the leading and trailing ends of the medium P is higher than when the leading and trailing end detection units detect each of the leading and trailing ends of the medium while it is being transported by an upstream transport unit that transports the medium while gradually reducing the transport speed from the transport speed upstream of the leading end detection unit in the transport direction.

[0025] According to the configuration of the ninth aspect, the load (i.e., stress) acting on the medium can be reduced compared to when the leading end detection unit and the trailing end detection unit each detect the leading end and trailing end of the medium when the upstream conveying unit is positioned in the clamping position. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating a configuration in which an electrophotographic image forming unit is used in an image forming apparatus according to an embodiment of the present invention. [Figure 3] 10 is a schematic diagram illustrating a configuration in which a medium storage unit is disposed on a side of a conveyance path in an image forming apparatus according to the present embodiment. FIG. [Figure 4] 1 is a side cross-sectional view showing the configuration of a detection device according to an embodiment of the present invention. [Figure 5] FIG. 1 is a plan view showing a configuration of a detection device according to an embodiment of the present invention. [Figure 6] 1 is a side cross-sectional view showing the configuration of a detection device according to an embodiment of the present invention. [Figure 7] FIG. 2 is a block diagram showing an example of a hardware configuration of a control device according to the present embodiment. [Figure 8] FIG. 2 is a block diagram showing an example of a functional configuration of a processor of the control device according to the present embodiment. [Figure 9] FIG. 4 is a diagram showing a timing chart in the detection device according to the present embodiment. [Figure 10] 10 is a diagram illustrating measurement of the length in the transport direction of a medium having a cutting error. [Figure 11] 10 is a diagram illustrating measurement of the length of a skewed medium in the transport direction. [Figure 12] 1 is a diagram illustrating measurement of the width direction length of a medium. [Figure 13] 10 is a diagram illustrating a case where a side edge of an upstream portion of a medium in the transport direction is detected. [Figure 14] 10 is a diagram illustrating a case where a side edge portion of a medium on the downstream side in the transport direction is detected. DETAILED DESCRIPTION OF THE INVENTION

[0027] An example of an embodiment of the present invention will be described below with reference to the drawings.

[0028] (Image forming device 10) The configuration of an image forming apparatus 10 according to this embodiment will be described below. Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 10 according to this embodiment.

[0029] In addition, the arrow UP shown in the figure indicates the top (vertically upward) of the device, and the arrow DO indicates the bottom (vertically downward) of the device. Also, the arrow LH shown in the figure indicates the left side of the device, and the arrow RH indicates the right side of the device. Also, the arrow FR shown in the figure indicates the front of the device, and the arrow RR indicates the rear of the device. These directions are defined for the convenience of explanation, and the device configuration is not limited to these directions. In addition, in each direction of the device, the word "device" may be omitted. That is, for example, "above the device" may be simply expressed as "above."

[0030] In the following description, the "up-down direction" may be used to mean "both above and below" or "either above or below." The "left-right direction" may be used to mean "both right and left" or "either right or left." The "left-right direction" may also be referred to as the lateral direction or horizontal direction. The "front-rear direction" may be used to mean "both forward and backward" or "either forward or backward." The front-rear direction corresponds to the width direction described below, and may also be referred to as the lateral direction or horizontal direction. The up-down direction, left-right direction, and front-rear direction are directions that intersect with each other (specifically, directions that are perpendicular to each other).

[0031] In addition, the symbol "x" inside a "circle" in the figure indicates an arrow pointing from the front to the back of the page. In addition, the symbol "·" inside a "circle" in the figure indicates an arrow pointing from the back to the front of the page.

[0032] The image forming apparatus 10 shown in Fig. 1 is an apparatus for forming an image. Specifically, the image forming apparatus 10 is an inkjet image forming apparatus that forms an image on a medium P using ink. More specifically, as shown in Fig. 1, the image forming apparatus 10 has an image forming apparatus main body 11, a medium storage unit 12, a medium discharge unit 13, an image forming unit 14, a heating unit 19, a conveying mechanism 20, a detection device 500, and a control device 160.

[0033] The medium P, each part of the image forming apparatus 10, and the image forming operation in the image forming apparatus 10 will be described below.

[0034] (Medium P) The medium P is a target on which an image is formed by the image forming unit 14. Types of the medium P include, for example, paper and film. Examples of paper include cardboard and coated paper. Examples of film include resin film and metal film. In this embodiment, for example, paper is used as the medium P. Note that the types of the medium P are not limited to those described above, and various types of medium P can be used.

[0035] The size (i.e., dimensions) of the medium P is, for example, A3+ or larger, including sizes such as A2, A1, A0, and B series. Note that the size of the medium P is not limited to the above, and various sizes of medium P can be used.

[0036] Here, the length of the medium P along the transport direction is referred to as the transport direction length. The direction intersecting the transport direction of the medium P (specifically, the perpendicular direction) is referred to as the width direction, and the length along the width direction of the medium P is referred to as the width direction length. Note that the width direction is an example of the perpendicular direction. In each figure, the transport direction is indicated by an arrow H as appropriate.

[0037] In this embodiment, the upstream end of the medium P in the transport direction may be referred to as the leading end or the upstream end. The downstream end of the medium P in the transport direction may be referred to as the trailing end or the downstream end. The widthwise ends of the medium P may be referred to as the side ends.

[0038] (Image forming apparatus main body 11) 1, the image forming apparatus main body 11 is a portion in which each component of the image forming apparatus 10 is provided. Specifically, for example, the medium storage unit 12, the image forming unit 14, the heating unit 19, the conveying mechanism 20, and the detection device 500 are arranged inside the image forming apparatus main body 11.

[0039] The detection device 500 is detachably disposed in the image forming apparatus main body 11. In other words, the detection device 500 is detachably attached to the image forming apparatus main body 11.

[0040] (medium storage section 12) The medium container 12 is a portion of the image forming apparatus 10 that contains the medium P. The medium P contained in the medium container 12 is supplied to the image forming unit 14.

[0041] (Media discharge section 13) The medium discharge unit 13 is a portion of the image forming apparatus 10 to which the medium P is discharged. The medium P on which an image has been formed by the image forming unit 14 is discharged to the medium discharge unit 13.

[0042] (Image forming unit 14) 1 is an example of an image forming unit that forms an image on a medium P. Specifically, the image forming unit 14 forms an image on the medium P using ink. More specifically, the image forming unit 14 has ejection units 15Y, 15M, 15C, and 15K (hereinafter referred to as 15Y to 15K), a transfer body 16, and an opposing member 17 that faces the transfer body 16, as shown in FIG.

[0043] In the image forming unit 14, each of the ejection units 15Y to 15K ejects ink droplets of each color, yellow (Y), magenta (M), cyan (C), and black (K), onto the transfer body 16 to form an image on the transfer body 16. Furthermore, in the image forming unit 14, the image of each color formed on the transfer body 16 is transferred to the medium P passing through a transfer position TA between the transfer body 16 and an opposing member 17. In this way, an image is formed on the medium P. The transfer position TA can also be said to be an image forming position where an image is formed on the medium P.

[0044] Note that the image forming unit is not limited to the configuration of the image forming unit 14. For example, the image forming unit may have a configuration in which each of the ejection units 15Y to 15K ejects ink droplets directly onto the medium P without using the transfer body 16.

[0045] (Image forming unit 214) As an example of the image forming section, as shown in FIG. 2, an electrophotographic image forming section 214 that forms an image on the medium P using toner may be used.

[0046] As shown in FIG. 2, the image forming section 214 includes toner image forming sections 215Y, 215M, 215C, and 215K (hereinafter referred to as 215Y to 215K), a transfer body 216, and a transfer member 217.

[0047] In image forming unit 214, toner image forming units 215Y to 215K perform the steps of charging, exposing, developing, and transferring to form toner images of the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) on transfer body 216. The toner images of the respective colors formed on transfer body 216 are transferred by transfer member 217 to medium P passing through transfer position TA between transfer body 216 and transfer member 217. In this way, an image is formed on medium P. In this way, an example of an image forming apparatus may be an electrophotographic image forming apparatus.

[0048] As an example of the image forming section, each of the toner image forming sections 215Y to 215K may be configured to form a toner image directly on the medium P without using the transfer body 216.

[0049] (Heating section 19) 1 is an example of a heating section that heats the medium P on which an image has been formed by the image forming section 14. As an example, the heating section 19 heats the medium P without contacting the medium P using a heat source (not shown), thereby drying the ink image.

[0050] An example of the heating unit is not limited to the above-mentioned heating unit 19. An example of the heating unit may be, for example, a device that heats the medium P by contacting the medium P within a range that does not affect the image, and various heating units can be used.

[0051] In an electrophotographic image forming apparatus equipped with the image forming section 214, the heating section 19 functions as, for example, a fixing device that fixes a toner image by heating.

[0052] (Transport mechanism 20) The transport mechanism 20 is a mechanism that transports the medium P. As an example, the transport mechanism 20 transports the medium P using a transport member 29 such as a transport roll. Note that the transport member 29 may be a transport belt or the like, as long as it is a member that can apply a transport force to the medium P and transport the medium P.

[0053] The transport mechanism 20 transports the medium P from the medium storage unit 12 to the image forming unit 14 (specifically, the transfer position TA). Furthermore, the transport mechanism 20 transports the medium P from the image forming unit 14 to the heating unit 19. Furthermore, the transport mechanism 20 transports the medium P from the heating unit 19 to the medium discharge unit 13. Furthermore, the transport mechanism 20 transports the medium P from the heating unit 19 to the image forming unit 14.

[0054] Therefore, the image forming apparatus 10 is formed with a transport path 21 from the medium storage unit 12 to the image forming unit 14, a transport path 22 from the image forming unit 14 to the heating unit 19, and a transport path 23 from the heating unit 19 to the medium discharge unit 13. Furthermore, the image forming apparatus 10 is formed with a transport path 24 from the heating unit 19 to the image forming unit 14.

[0055] The transport path 24 is a transport path that returns the medium P, on one side of which an image has been formed, to the image forming unit 14 (specifically, the transfer position TA). The transport path 24 is also a transport path that turns over the medium P, on one side of which an image has been formed.

[0056] A portion of the transport path 21 and the transport path 24 (specifically, a portion downstream in the transport direction) is shared. Therefore, it is possible to understand that the transport path 25, along which the medium P is transported from the medium storage unit 12, is connected to the transport path 24, and that the medium P is supplied from the medium storage unit 12 to the transport path 24. Therefore, the connection position where the transport path 25 is connected to the transport path 24 can be understood as a supply position 25A where new medium P from the medium storage unit 12 is supplied to the transport path 24 toward the image forming unit 14. In other words, in this embodiment, the medium P is supplied from the supply position 25A to the image forming unit 14 through the transport path 24.

[0057] (Image Forming Operation in Image Forming Apparatus 10) In the image forming apparatus 10, the medium P is transported from the medium storage unit 12 to the image forming unit 14 (specifically, the transfer position TA) via the transport path 21, and an image (hereinafter sometimes referred to as a "front image") is formed on one side (i.e., the front side) of the medium P by the image forming unit 14. When an image is formed on only one side of the medium P, the medium P with the front image formed on one side passes through the heating unit 19 and is discharged to the medium discharge unit 13.

[0058] On the other hand, when forming images on both sides of medium P, medium P with a front image formed on one side passes through heating section 19 and is transported along transport path 24, where it is turned over and returned to image forming section 14 (specifically, transfer position TA). Then, an image is formed on the other side (i.e., the back side) of medium P by image forming section 14, and medium P is then discharged to medium discharge section 13 via heating section 19. In this way, one side and the other side of medium P are image forming surfaces on which images are formed.

[0059] (Position of the medium storage unit 12) 1, the medium container 12 is disposed below the transport path 24. Therefore, the medium P in the medium container 12 is supplied to the supply position 25A of the transport path 24 from below.

[0060] As shown in FIG. 3, the medium storage unit 12 may be disposed laterally relative to the transport path 24. In this case, the medium P in the medium storage unit 12 is supplied from the side (the right side in FIG. 3) to the supply position 25A of the transport path 24. In the configuration shown in FIG. 3, the medium storage unit 12 is disposed laterally relative to the image forming unit 14 (specifically, the transfer position TA). This allows the medium P to be supplied from the side to the image forming unit 14 (specifically, the transfer position TA). The image forming apparatus main body 11 is not shown in FIG. 3.

[0061] (Detection device 500) The detection device 500 shown in Fig. 1 is an example of a detection device that detects the edge of the medium P. Note that the detection device 500 is shown in a simplified form in Fig. 1.

[0062] Fig. 4 is a side cross-sectional view showing the configuration of detection device 500. Fig. 5 is a plan view showing the configuration of detection device 500. Note that Figs. 4 to 6 and 10 to 14 show the device in a state where the left and right sides are reversed compared to Figs. 1 to 3. That is, in Figs. 4 to 6 and 10 to 14, the left and right sides of the device are shown facing inversely to the left and right sides on the paper.

[0063] Here, in the detection device 500, "detecting (or sensing) the edge" is not limited to directly detecting (or sensing) the edge (i.e., the edge) of the medium P itself, but also includes, for example, detecting (or sensing) a mark (such as a registration mark) attached to the edge of the medium P. The mark is attached at a predetermined distance from the edge of the medium P, and the distance from the edge of the medium P is known.

[0064] 4, the detection device 500 includes a first support 510, a second support 520, a transport mechanism 503, detection units 610 and 620, and a front end sensor 627. The configuration of each unit of the detection device 500 will be described below.

[0065] (First support 510) The first support 510 shown in FIG. 4 has a function of supporting a part of the transport mechanism 503 (specifically, drive rolls 531, 541, 551, 561, and 571, which will be described later).

[0066] 4, the first support 510 constitutes the lower part of the detection device 500. As an example, the first support 510 is formed in a flat shape that is thin in the up-down direction and wide in the front-rear and left-right directions.

[0067] The first support 510 has a guide plate 514 that guides the medium P. The guide plate 514 faces the lower surface of the medium P and guides the medium P transported by the transport mechanism 503 downstream in the transport direction.

[0068] (Second support 520) The second support 520 shown in FIGS. 4 and 5 has a function of supporting other parts of the transport mechanism 503 (specifically, driven rolls 532, 542, 552, 562, and 572, which will be described later).

[0069] 4, the second support 520 constitutes the upper part of the detection device 500. As an example, the second support 520 is formed in a flat shape that is thin in the up-down direction and widens in the front-rear and left-right directions.

[0070] The second support 520 has a guide plate 524 that guides the medium P. The guide plate 524 faces the upper surface of the medium P and guides the medium P transported by the transport mechanism 503 downstream in the transport direction.

[0071] (Transport mechanism 503) The transport mechanism 503 shown in FIGS. 4 and 5 is a mechanism that transports the medium P in the detection device 500. As shown in FIGS. 4 and 5, the transport mechanism 503 has transport rolls 530, 540, 550, 560, and 570. The transport rolls 530, 540, 550, 560, and 570 are arranged in this order toward the downstream side in the transport direction. Each of the transport rolls 530, 540, 550, 560, and 570 has the function of transporting the medium P and is configured as a pair of rolls as shown in FIG. 4. Specifically, the transport rolls 530, 540, 550, 560, and 570 each have a drive roll 531, 541, 551, 561, and 571, and a driven roll 532, 542, 552, 562, and 572.

[0072] The driving rolls 531, 541, 551, 561, and 571 are disposed below the driven rolls 532, 542, 552, 562, and 572, and are driven to rotate to apply a conveying force to the medium P.

[0073] The driven rolls 532, 542, 552, 562, and 572 are disposed above the drive rolls 531, 541, 551, 561, and 571, and rotate following the drive rolls 531, 541, 551, 561, and 571.

[0074] The driven rolls 532, 542, 552, 562, and 572 are supported by the second support 520 so as to be movable between a clamping position (position indicated by a solid line in FIG. 4) where they clamp the medium P with the drive rolls 531, 541, 551, 561, and 571, and a separated position (position indicated by a two-dot chain line in FIG. 4) where they are separated from the medium P. The transport rolls 530, 540, 550, 560, and 570 transport the medium P with the driven rolls 532, 542, 552, 562, and 572 positioned at the clamping position.

[0075] The transport roll 550 is an example of a transport unit, and has a function of transporting the medium P to the transport roll 560.

[0076] The transport roll 560 is provided downstream in the transport direction relative to the transport roll 550. This transport roll 560 is an example of an abutting section, and is an abutting roll that abuts against the front end of the medium P. Hereinafter, the transport roll 560 may also be referred to as the abutting roll 560. The abutting roll 560 has the function of correcting the inclination (i.e., skew) of the medium P by abutting against the front end of the medium P transported by the transport roll 550.

[0077] The transport roll 570 is provided downstream in the transport direction relative to the transport roll 560. This transport roll 570 is a correction roll that corrects misalignment of the medium P in the width direction. Hereinafter, the transport roll 570 may also be referred to as the correction roll 570. The correction roll 570 corrects misalignment of the medium P in the width direction by moving along the width direction while sandwiching the medium P based on the detection results of the detection unit 620. In this embodiment, the abutment roll 560 and the correction roll 570 together serve as adjustment units that adjust the tilt and misalignment of the medium P, and the medium P is transported to the image forming unit 14 (specifically, the transfer position TA) with the attitude, etc. of the medium P adjusted by this adjustment unit.

[0078] The transport rolls 530 and 540 are provided upstream in the transport direction relative to the transport roll 550. The transport rolls 530 and 540 are an example of an upstream transport section, and transport the medium P toward the transport roll 550.

[0079] In this embodiment, the transport roll 550 transports the medium P at a constant speed and at a transport speed slower than the transport speed on the upstream side in the transport direction relative to the leading end sensor 612 (described later). Specifically, the transport roll 550 transports the medium P at a constant speed and at a transport speed slower than the transport speed when the medium P is transported upstream in the transport direction relative to the transport roll 550.

[0080] Although the transport mechanism 503 includes the transport rolls 530, 540, 550, 560, and 570, the present invention is not limited to this. For example, a transport member such as a transport belt may be included instead of the transport rolls 530, 540, 550, 560, and 570. That is, an example of the transport unit and an example of the upstream transport unit are not limited to the transport rolls 530, 540, and 550, and a transport member such as a transport belt may be used. Furthermore, an example of the abutting unit is not limited to the abutting roll 560, and may be a transport member such as a transport belt, as long as it abuts against the leading edge of the medium P transported from the upstream side of the transport roll 550 in the transport direction.

[0081] (Detection unit 610) 4 and 5 is an example of a first detection unit, and has the function of detecting the leading and trailing edges of the medium P being transported. As shown in FIGS. 4 and 5, the detection unit 610 has a leading edge sensor 612 and a trailing edge sensor 614.

[0082] The leading edge sensor 612 is an example of a leading edge detection unit, and detects the leading edge of the medium P being transported. Specifically, the leading edge sensor 612 is a non-contact sensor that detects the leading edge of the medium P without coming into contact with the medium P. Even more specifically, the leading edge sensor 612 is an optical sensor that uses light irradiated toward the medium P. Even more specifically, the leading edge sensor 612 is a reflective optical sensor that detects the leading edge of the medium P by detecting reflected light of light irradiated onto the medium P. Note that a transmissive optical sensor may also be used as the leading edge sensor 612.

[0083] The trailing edge sensor 614 is an example of a trailing edge detection unit, and detects the trailing edge of the medium P being transported. As shown in FIG. 5, the leading edge sensor 612 and the trailing edge sensor 614 are arranged so as to overlap when viewed in the transport direction. Specifically, the leading edge sensor 612 and the trailing edge sensor 614 are arranged side by side along the transport direction (specifically, the left-right direction). Note that as viewed in the transport direction, this refers to a view from either the upstream or downstream side in the transport direction toward the other. Furthermore, "overlapping" here does not necessarily mean complete overlap, as long as there is at least a partial overlap.

[0084] 4 and 5, in this embodiment, the detection unit 610 is provided upstream of the abutting roll 560 in the transport direction. Specifically, the leading end sensor 612 is provided upstream of the abutting roll 560 in the transport direction and downstream of the transport roll 550 in the transport direction. The trailing end sensor 614 is provided upstream of the transport roll 530 in the transport direction.

[0085] The trailing edge sensor 614 is a non-contact sensor that detects the trailing edge of the medium P without coming into contact with the medium P. More specifically, the trailing edge sensor 614 is an optical sensor that uses light irradiated toward the medium P. More specifically, as shown in FIG. 4, the trailing edge sensor 614 has multiple detection elements 616 (specifically, light-emitting elements and light-receiving elements) arranged along the transport direction and is configured as a line sensor that is elongated in the transport direction. More specifically, as an example, the trailing edge sensor 614 is configured as a contact image sensor (CIS). Note that a line sensor other than a contact image sensor may also be used as the trailing edge sensor 614.

[0086] The rear end sensor 614 has a detection area 614R that detects the rear end of the medium P, from the detection element 616(X) located at the most upstream side in the transport direction to the detection element 616(Y) located at the most downstream side in the transport direction.

[0087] The trailing end sensor 614 detects the position of the trailing end of the medium P at the boundary between detection and non-detection of each detection element 616 in the detection area 614R, and position information indicated by its coordinates (specifically, the number of pixels from the downstream end of the detection area 614R in the conveying direction) is sent to, for example, the control device 160.

[0088] 4, in the detection unit 610, the distance D1 between the detection element 616(X), which is located on the most upstream side of the trailing edge sensor 614 in the transport direction, and the leading edge sensor 612 is shorter than the length D2 in the transport direction of the maximum-sized medium P. In other words, when the leading edge of the maximum-sized medium P is detected by the leading edge sensor 612, the trailing edge of the medium P protrudes from the detection area 614R toward the upstream side in the transport direction. Note that the detection area 614R is positioned so that the leading edge of the maximum-sized medium P is downstream in the transport direction from the leading edge sensor 612 and the trailing edge of the medium P is located within the range of the detection area 614R before it reaches the abutment roll 560.

[0089] In this embodiment, as shown by the reference symbols (A) and (B) in Fig. 5, two sets of the front end sensor 612 and the rear end sensor 614 are arranged. Specifically, the front end sensor 612 and the rear end sensor 614 are arranged in a front portion and a rear portion of the detection device 500.

[0090] In the detection unit 610, as shown in FIG. 6, the front end sensor 612 and the rear end sensor 614 each detect the front end and rear end of the medium P while it is being transported by the transport roll 550, with the driven rolls 532 and 542 of the transport rolls 530 and 540 positioned in the separated position.

[0091] Although the detection unit 610, which is an example of a first detection unit, has the above-described configuration, it is not limited to this configuration. As an example of a first detection unit, for example, a pair of the leading edge sensor 612 and the trailing edge sensor 614 may be arranged. As another example of a first detection unit, the leading edge sensor 612 and the trailing edge sensor 614 may be arranged so as to be offset in the width direction. As an example of a first detection unit, it is sufficient that it detects the leading edge and trailing edge of the medium P being transported.

[0092] (Front end sensor 627) 4 and 5 has a function of detecting the leading end of the medium P being transported and is detected by the detection unit 610. Specifically, the leading end sensor 627 is provided downstream of the correction roll 570 in the transport direction.

[0093] The front end sensor 627 detects the front end of the medium P being transported by the correction roll 570 with the transport rolls 530, 540, 550 and the driven rolls 532, 542, 552, 562 of the abutting roll 560 positioned at the separated positions.

[0094] Specifically, the leading edge sensor 627 is a non-contact sensor that detects the leading edge of the medium P without coming into contact with the medium P. Even more specifically, the leading edge sensor 627 is an optical sensor that uses light irradiated toward the medium P. Even more specifically, the leading edge sensor 627 is a reflective optical sensor that detects the edge of the medium P by detecting reflected light of light irradiated onto the medium P. Note that a transmissive optical sensor may also be used as the leading edge sensor 627.

[0095] (Detection unit 620) 4 and 5 is an example of a second detection unit, and has a function of detecting both widthwise ends (i.e., a pair of side ends) of the medium P being transported and detected by the detection unit 610. The detection unit 620 has a pair of side end sensors 628, as shown in FIG.

[0096] The pair of side edge sensors 628 detects one end and the other end in the width direction of the medium P. Furthermore, the pair of side edge sensors 628 are arranged to face each other in the width direction (see FIGS. 13 and 14). That is, the detection unit 620 is divided into a portion that detects one end in the width direction of the medium P and a portion that detects the other end, and these are arranged to face each other in the width direction.

[0097] In this embodiment, as shown in Fig. 5, the pair of side edge sensors 628 is composed of a side edge sensor 628(A) on the front side of the device and a side edge sensor 628(B) on the rear side of the device, and detects each of the pair of side edges of the medium P being transported. The pair of side edge sensors 628 are arranged so as to overlap when viewed in the width direction. Specifically, the pair of side edge sensors 628 are arranged side by side in the width direction (specifically, the front-to-rear direction).

[0098] In this embodiment, the detection unit 620 is provided downstream in the transport direction from the abutting roll 560. Specifically, the detection unit 620 is provided downstream in the transport direction from the front end sensor 627.

[0099] The pair of side edge sensors 628 are non-contact sensors that detect the pair of side edges of the medium P without coming into contact with the medium P. More specifically, the pair of side edge sensors 628 are optical sensors that use light irradiated toward the medium P. More specifically, as shown in FIG. 5, the pair of side edge sensors 628 are configured as line sensors that are elongated in the width direction and have multiple detection elements 629 (specifically, light-emitting elements and light-receiving elements) arranged along the width direction. More specifically, the pair of side edge sensors 628 are configured as contact image sensors (CIS), as an example. Note that line sensors other than contact image sensors may also be used as the pair of side edge sensors 628.

[0100] The pair of side edge sensors 628 have a detection region 628R that detects the side edge of the medium P, from the detection element 629(X) located on one end side in the width direction to the detection element 629(Y) located on the other end side in the width direction.

[0101] The pair of side edge sensors 628 detect the position of the side edge of the medium P at the boundary between detection and non-detection of each detection element 629 in the detection area 628R, and position information indicated by the coordinates (specifically, the number of pixels from the front end of the detection area 628R) is sent to, for example, the control device 160.

[0102] In the detection section 620, a pair of side edge sensors 628 detect each of a pair of side edges of the medium P being transported by the correction roll 570 with the transport rolls 530, 540, 550 and the driven rolls 532, 542, 552, 562 of the abutment roll 560 positioned in a spaced apart position.

[0103] Although the detection unit 620, which is an example of a second detection unit, has the above-described configuration, it is not limited to this configuration. As an example of a second detection unit, for example, multiple pairs of side edge sensors 628 may be arranged. As another example of a second detection unit, the pairs of side edge sensors 628 may be arranged offset in the transport direction. Furthermore, although the detection unit 620 was arranged downstream in the transport direction relative to the detection unit 610, it may be arranged upstream in the transport direction relative to the detection unit 610. As an example of a second detection unit, it is sufficient if it detects both ends of the medium P detected by the first detection unit, in a direction perpendicular to the transport direction, of the medium P being transported.

[0104] (Control device 160) Here, the configuration of the control device 160 will be described. The control device 160 has a control function that controls the operation of each unit of the image forming device 10, including each unit of the detection device 500. Furthermore, the control device 160 has a measurement function that measures the length of the medium P based on the detection results of the detection units 610 and 620. Specifically, as shown in FIG. 7, the control device 160 has a processor 161, a memory 162, a storage 163, and a timer 164.

[0105] The term "processor" refers to a processor in a broad sense, and processor 161 may be a general-purpose processor (e.g., a CPU (Central Processing Unit)) or a dedicated processor (e.g., a GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0106] The storage 163 stores various programs including a control program 163A (see FIG. 8) and various data. Specifically, the storage 163 is realized by a recording device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory.

[0107] Memory 162 is a work area for processor 161 to execute various programs, and temporarily records various programs or various data when processor 161 executes processing. Processor 161 reads various programs including control program 163A from storage 163 into memory 162, and executes the programs using memory 162 as a work area. Timer 164 is a measurement unit for measuring elapsed times X, Y, etc., which will be described later.

[0108] In the control device 160, the processor 161 executes the control program 163A to realize various functions. The following describes the functional configuration realized by the cooperation of the processor 161 as a hardware resource and the control program 163A as a software resource. Figure 8 is a block diagram showing the functional configuration of the processor 161.

[0109] As shown in FIG. 8, in the control device 160, the processor 161 executes a control program 163A to function as an acquisition unit 161A, a measurement unit 161B, and a control unit 161C.

[0110] The control unit 161C controls the transport mechanism 503, the detection units 610 and 620, and the front end sensor 627 to perform the detection operation described below.

[0111] As shown in FIG. 9 , the transport mechanism 503 transports the medium P at a predetermined transport speed 1 using, for example, transport rolls 530 and 540, and transports the medium P while decelerating to a transport speed 2 that is slower than the transport speed 1. In the transport mechanism 503, for example, the transport roll 550 receives the medium P from the transport rolls 530 and 540 and transports the medium P at a constant speed, that is, at transport speed 2. When the transport roll 550 transports the medium P, the driven rolls 532 and 542 of the transport rolls 530 and 540 move to the separated positions. In other words, the transport roll 550 alone transports the medium P toward the abutment roll 560 at a constant speed, that is, at transport speed 2 (see FIG. 6 ). Note that the constant speed may be an approximately constant speed, and does not have to be a completely constant speed.

[0112] When the leading edge sensor 612 of the detection unit 610 detects the leading edge of the medium P being transported by the transport rolls 550, the trailing edge sensor 614 detects the trailing edge of the medium P after a predetermined time (hereinafter referred to as elapsed time X) has elapsed. At this time, the leading edge of the medium P is located upstream of the abutting rolls 560 in the transport direction (see FIG. 6). In other words, the trailing edge is detected before the leading edge of the medium P abuts against the abutting rolls 560. Furthermore, the leading edge sensor 612 and the trailing edge sensor 614 each detect the leading edge and the trailing edge of the medium P when it is being transported independently by the transport rolls 550.

[0113] In the case of a maximum-sized medium P, when the leading edge is detected by the leading edge sensor 612, the trailing edge is located upstream in the conveying direction relative to the detection area 614R of the trailing edge sensor 614 (see FIG. 5), and after a predetermined elapsed time X has elapsed, the trailing edge is located within the detection area 614R of the trailing edge sensor 614 (see FIG. 6). In the case of a minimum-sized medium P, both when the leading edge is detected by the leading edge sensor 612 and after the predetermined elapsed time X has elapsed, the trailing edge is located within the detection area 614R of the trailing edge sensor 614.

[0114] Furthermore, the transport roll 550 transports the medium P for a predetermined time after the medium P hits the abutting roll 560, and stops transporting after the front end of the medium P hits the abutting roll 560 from one end to the other in the width direction.

[0115] Thereafter, the abutting roll 560 transports the medium P. When the abutting roll 560 transports the medium P, the transport rolls 530, 540, and 550 move the driven rolls 532, 542, and 552 to the separated positions. In other words, the abutting roll 560 transports the medium P toward the correction roll 570 by itself.

[0116] Thereafter, the correction roll 570 transports the medium P. When the correction roll 570 transports the medium P, the transport rolls 530, 540, 550 and the abutting roll 560 move the driven rolls 532, 542, 552, 562 to the separated positions. In other words, the correction roll 570 transports the medium P solely downstream in the transport direction.

[0117] When the leading edge sensor 627 of the detection unit 620 detects the leading edge of the medium P being transported by the correction roll 570, after a predetermined time (hereinafter referred to as elapsed time Y) has elapsed, the pair of side edge sensors 628 detect the pair of side edges of the medium P. The leading edge sensor 627 and the pair of side edge sensors 628 detect the pair of side edges of the medium P when it is being transported by the correction roll 570 alone.

[0118] The correction roll 570 corrects misalignment of the medium P in the width direction by moving along the width direction based on the amount of misalignment detected by the detection unit 620 (see below).

[0119] In addition, when the image forming unit 214 is used as the image forming unit, the abutting roll 560 resumes transporting the medium P so that the timing when the toner image formed on the transfer body 216 reaches the transfer position TA and the timing when the medium P reaches the transfer position TA are synchronized.

[0120] The acquisition unit 161A acquires detection information obtained by the detection units 610, 620 detecting the leading end, trailing end, and pair of side ends of the medium P. The detection information for the trailing end and pair of side ends includes position information indicating the positions of the trailing end and pair of side ends of the medium P. Specifically, the position information is position information indicating the position in the transport direction for the trailing end of the medium P, and is position information indicating the position in the width direction of the medium P for the side ends of the medium P.

[0121] Specifically, the acquisition unit 161A, for example, detects the position of the rear end of the medium P at the boundary between detection and non-detection of the individual detection elements 616 in the detection area 614R by the rear end sensor 614, and acquires position information indicated by its coordinates (specifically, the number of pixels from the downstream end of the detection area 614R in the transport direction).

[0122] In addition, the acquisition unit 161A, for example, detects the position of the side edge of the medium P at the boundary between detection and non-detection of each of the pair of side edge sensors 628 in the detection area 628R of the individual detection elements 629, and acquires position information indicated by the coordinates (specifically, the number of pixels from the front end of the detection area 628R).

[0123] The measuring unit 161B measures the length of the medium P in the transport direction based on the position information acquired by the acquiring unit 161A, for example, as follows.

[0124] For example, based on the position information, the measurement unit 161B determines the distance LA (see Figure 6) from the downstream end of the detection area 614R of the trailing end sensor 614 in the conveying direction (i.e., the detection element 616(Y) arranged on the most downstream side in the conveying direction) to the trailing end of the medium P.

[0125] Specifically, the distance LA is calculated using the following formula (1) based on the total number of pixels P1 (pixels / mm) of the detection element 616 of the trailing end sensor 614 and the number of pixels P2 (pixels) from the downstream end of the detection area 614R of the trailing end sensor 614 in the transport direction to the trailing end of the medium P.

[0126] Formula (1): LA = P2 ÷ P1

[0127] The distance LB (see FIG. 6) from the downstream end of the detection area 614R of the trailing end sensor 614 in the transport direction to the leading end sensor 612 is known. Furthermore, by multiplying the known transport speed 2 by the known elapsed time X, the distance LC (see FIG. 6) from the leading end sensor 612 to the leading end of the medium P is determined in advance as a known value. Then, the measurement unit 161B determines the length L1 of the medium P in the transport direction using the following equation (2):

[0128] Equation (2): L1 = LA + LB + LC

[0129] In this embodiment, as shown in Fig. 10, the transport direction length L1 of one end portion and the other end portion in the width direction of the medium P is measured based on the detection results of two sets of leading end sensors 612(A)(B) and trailing end sensors 614(A)(B). Note that Figs. 10 to 12 schematically show the two sets of leading end sensors 612(A)(B) and trailing end sensors 614(A)(B).

[0130] Here, when paper is used as the medium P, the conveying direction length L1 may differ between one end portion and the other end portion of the medium P in the width direction due to cutting error, as shown in Fig. 10, and it is possible to measure this cutting error. Note that the average, minimum, and maximum values ​​of the conveying direction length L1 between one end portion and the other end portion of the medium P in the width direction can be used as the conveying direction length of the medium P.

[0131] 11, it is possible to detect skew of the medium P from the difference in detection timing between the two pairs of front end sensors 612(A)(B). When the medium P skews, an error may occur between the calculated transport direction length L1 and the true transport direction length Lm.

[0132] Therefore, to correct this error, the amount of skew can be calculated from the transport speed 2(v) of the medium P, the time difference Δt between the leading end sensors 612(A) and (B), and the distance X between the leading end sensors 612(A) and (B), as shown in the following equation (3), and correction can be performed to obtain the true paper length Lm.

[0133] Equation (3): Lm=(√((Δt÷v) 2 +X 2 )÷X)×L1

[0134] The measuring unit 161B measures the width direction length W1 of the medium P, for example, as follows, based on the position information acquired by the acquiring unit 161A.

[0135] For example, based on the position information, the measurement unit 161B determines the distance WA (see Figure 12) from the front end of the detection area 628R of the side edge sensor 628(A) (i.e., the detection element 629(Y) arranged on the front end side) to one side edge of the medium P (specifically, the side edge on the front side of the device).

[0136] Specifically, the distance WA is calculated using the following equation (4) based on the total number of pixels P3 (pixels / mm) of the detection element 629 of the side edge sensor 628(A) and the number of pixels P4 (pixels) from the front end of the detection area 628R of the side edge sensor 628(A) to one side end (specifically, the side end on the front side of the device).

[0137] Equation (4) WA = P4 ÷ P3

[0138] Furthermore, based on the position information, the measurement unit 161B determines the distance WB (see FIG. 12) from the front end of the detection area 628R of the side edge sensor 628(B) (i.e., the detection element 629(Y) arranged on the front end side) to the other side edge of the medium P (specifically, the side edge on the rear side of the device).

[0139] Specifically, the distance WB is calculated using the following equation (5) based on the total number of pixels P5 (pixels / mm) of the detection element 629 of the side edge sensor 628(B) and the number of pixels P6 (pixels) from the front end of the detection area 628R of the side edge sensor 628(B) to the other side end (specifically, the side end on the rear side of the device).

[0140] Formula (5) WB=P6÷P5

[0141] The distance WC from the front end of the detection area 614R of the side edge sensor 628(A) to the front end of the detection area 614R of the side edge sensor 628(B) is known. Then, the measurement unit 161B calculates the width direction length W1 of the medium P using the following equation (6).

[0142] Formula (6): W1=WC+WB-WA

[0143] Furthermore, the measurement unit 161B detects the amount of positional deviation in the width direction of the medium P based on the position information acquired by the acquisition unit 161A, for example, as follows.

[0144] Based on the position information, the measurement unit 161B, for example, determines the distance WA (see Figure 12) from the front end of the detection area 628R of the side edge sensor 628(A) (i.e., the detection element 629(Y) arranged on the front end side) to one side edge of the medium P (specifically, the side edge on the front side of the device), as described above.

[0145] Here, the distance WM (see Figure 12) from the front end of the detection area 628R of the side edge sensor 628(A) (i.e., the detection element 629(Y) arranged on the front end side) to one side edge of the medium P at the reference position of the medium P (specifically, the side edge on the front side of the device) is determined in advance as a known value.

[0146] The reference position of the medium P is a position in the width direction that is set in advance as a position where the medium P should be placed when the medium P is transported.

[0147] Then, the measurement unit 161B detects the amount of misalignment WN in the width direction of the medium P from the difference between the distance WM and the distance WA. In this way, the amount of misalignment WN in the width direction of the medium P is detected based on the detection result of the side edge sensor 628(A), which is an example of one of the detection units of the detection unit 620.

[0148] The measurement unit 161B may detect the amount of misalignment in the width direction of the medium P based on the distance WB from the front end of the detection area 628R of the side edge sensor 628(B) (i.e., the detection element 629(Y) arranged on the front end side) to the other side edge of the medium P (specifically, the side edge on the rear side of the device). The measurement unit 161B may also detect the amount of misalignment in the width direction of the medium P based on the distance WA and the distance WB.

[0149] In this embodiment, the pair of side edge sensors 628 may detect a pair of side edges (see FIG. 13) on the upstream side in the transport direction of the medium P and a pair of side edges (see FIG. 14) on the downstream side in the transport direction of the medium P. From the detection results, the width direction length W1 of the upstream side in the transport direction and the downstream side in the transport direction of the medium P may be measured.

[0150] Specifically, for example, after an elapsed time Y has elapsed since the front end sensor 627 of the detection unit 620 detected the front end of the medium P being transported by the correction roll 570, a pair of side end sensors 628 detect a pair of side ends of the medium P, thereby detecting a pair of side ends in the upstream portion of the transport direction of the medium P, as shown in Figure 13.

[0151] In the example shown in Figure 13, the pair of side edges of the medium P are detected at a position where the leading edge of the medium P is transported from the leading edge sensor 627 a distance M1 calculated by multiplying the transport speed by the correction roll 570 by the elapsed time Y.

[0152] Furthermore, after an elapsed time Z, which is longer than the elapsed time Y, has elapsed since the front end sensor 627 of the detection unit 620 detected the front end of the medium P being transported by the correction roll 570, a pair of side end sensors 628 detects a pair of side ends of the medium P, thereby detecting a pair of side ends in the downstream portion of the medium P in the transport direction, as shown in Figure 14.

[0153] 14, the pair of side edges of the medium P are detected at a position where the leading edge of the medium P has been transported from the leading edge sensor 627 a distance M2, which is the transport speed by the correction roll 570 multiplied by the elapsed time Z. Distance M2 is longer than distance M1.

[0154] Here, when paper is used as the medium P, the width direction length W1 may differ between the upstream and downstream portions of the medium P in the transport direction due to cutting errors, and it is possible to measure this cutting error. Note that the average, minimum, and maximum values ​​of the width direction length W1 of the upstream and downstream portions of the medium P in the transport direction can be used as the width direction length of the medium P.

[0155] Furthermore, in this embodiment, the pair of side edge sensors 628 detect a pair of side edges (see Figure 13) on the upstream side of the transport direction of the medium P and a pair of side edges (see Figure 14) on the downstream side of the transport direction of the medium P, and based on the detection results, the error that occurs between the calculated widthwise length W1 and the true widthwise length due to the medium P being skewed may be corrected.

[0156] 12 to 14, the front end sensor 627 and the pair of side end sensors 628 are shown schematically.

[0157] (Action according to this embodiment) In this embodiment, the detection unit 620 detects both widthwise ends (i.e., a pair of side ends) of the medium P detected by the detection unit 610 and being transported.

[0158] Therefore, the positions of the pair of side ends of the medium P being transported can be detected with greater accuracy than when the front and rear ends of the medium P being transported are detected and the length of the medium B in the width direction is estimated based on the length of the medium P in the transport direction.

[0159] 4 and 5, in this embodiment, the detection unit 620 is provided downstream in the transport direction relative to the abutting roll 560. This allows the detection unit 620 to detect a pair of side edges of the medium P when the medium P has been adjusted in position by the medium P abutting against the abutting roll 560. As a result, the detection accuracy of the detection unit 620 for detecting both ends of the medium P (i.e., a pair of side edges) is improved compared to when the detection unit 620 is provided upstream in the transport direction relative to the abutting roll 560.

[0160] In this embodiment, the detection unit 620 is divided into a portion that detects one end of the medium P in the width direction and a portion that detects the other end, and the portions are arranged to face each other in the width direction.

[0161] Therefore, compared to when the detection unit 620 is not divided and is composed of a single detection unit extending from one end side of the medium P in the width direction to the other end side, it is possible to avoid placing the detection unit in areas that are not necessary for detecting both ends of the medium P in the width direction.

[0162] In this embodiment, the side edge sensor 628(A), which is an example of one of the detecting units of the detecting unit 620, detects the amount of misalignment of the medium P in the width direction.

[0163] Therefore, compared to a case where a detector for detecting the amount of positional deviation in the width direction of the medium P is provided separately from the detector 620, the number of parts is reduced.

[0164] In this embodiment, as shown in FIGS. 4 and 5, the detection unit 610 is provided on the upstream side of the abutting roll 560 in the transport direction.

[0165] Here, in a configuration (hereinafter referred to as configuration A) in which the detection unit 610 is provided downstream in the transport direction from the abutting roll 560, the detection unit 610, which is long in the transport direction, is provided downstream in the transport direction from the abutting roll 560, so that the abutting roll 560 is positioned upstream in the transport direction in the transport path of the medium P in the detection device 500. As a result, the distance between the transfer position TA and the abutting roll 560 becomes longer, and the medium B, whose posture has been adjusted by the abutment of the abutting roll 560, may become skewed again.

[0166] In contrast, in this embodiment, the detection unit 610 is provided upstream of the abutting roll 560 in the transport direction, so the abutting roll 560 is positioned further downstream in the transport direction in the transport path of the medium P in the detection device 500. As a result, the distance between the transfer position TA and the abutting roll 560 is shorter, and compared to configuration A, the effect on the medium P whose posture has been adjusted by the abutting roll 560 when detected by the detection unit 610 is reduced.

[0167] In this embodiment, the detection unit 610 is provided on the upstream side of the correction roll 570 in the transport direction, as shown in FIGS.

[0168] Here, in a configuration (hereinafter referred to as configuration X) in which the detection unit 610 is provided downstream in the transport direction from the correction roll 570, the detection unit 610, which is long in the transport direction, is provided downstream in the transport direction from the correction roll 570, so that the correction roll 570 is disposed upstream in the transport direction in the transport path of the medium P in the detection device 500. As a result, the distance between the transfer position TA and the correction roll 570 becomes longer, and the medium B, whose positional deviation has been corrected by the correction roll 570, may become misaligned again.

[0169] In contrast, in this embodiment, the detection unit 610 is provided upstream of the correction roll 570 in the transport direction, so the correction roll 570 is disposed further downstream in the transport direction in the transport path of the medium P in the detection device 500. As a result, the distance between the transfer position TA and the correction roll 570 is shortened, and compared to the case of configuration X, the influence on the medium P whose positional deviation has been corrected by the correction roll 570 when detected by the detection unit 610 is suppressed.

[0170] In this embodiment, as shown in FIG. 4, the distance D1 between the detection element 616(X) located at the most upstream side of the trailing end sensor 614 in the transport direction and the leading end sensor 612 is shorter than the length D2 of the maximum size medium P in the transport direction.

[0171] Therefore, the detection device can be made smaller in length in the transport direction compared to when the distance D1 between the detection element 616(X) located at the most upstream side in the transport direction of the rear end sensor 614 and the front end sensor 612 is longer than the transport direction length D2 of the maximum size medium P.

[0172] In this embodiment, as shown by the reference symbols (A) and (B) in FIG. 5, two sets of the front end sensor 612 and the rear end sensor 614 are arranged so as to overlap each other when viewed in the conveying direction.

[0173] Therefore, the detection accuracy of the leading and trailing edges of the medium P is higher than in a configuration in which a pair of the leading edge sensor 612 and the trailing edge sensor 614 are arranged so as to overlap when viewed in the transport direction.

[0174] Also, in this embodiment, as shown in FIG. 6, the leading end sensor 612 and the trailing end sensor 614 each detect the leading end and the trailing end of the medium P while it is being transported by the transport roll 550, which transports the medium P at a constant speed and at a transport speed slower than the transport speed upstream of the leading end sensor 612 in the transport direction.

[0175] In a configuration (hereinafter referred to as configuration B) in which the leading end sensor 612 and the trailing end sensor 614 each detect the leading end and trailing end of the medium P being transported by a transport unit that transports the medium P while gradually slowing down the transport speed from the transport speed upstream in the transport direction relative to the leading end sensor 612, the leading end and trailing end of the medium P, whose speed fluctuates, are detected. Therefore, with this configuration, the detection accuracy of the leading end and trailing end of the medium P is higher than with configuration B.

[0176] In this embodiment, as shown in FIG. 6, the leading end sensor 612 and the trailing end sensor 614 detect the leading end and trailing end of the medium P, respectively, when the driven rolls 532, 542 of the transport rolls 530, 540 are positioned in the separated position.

[0177] Therefore, the load (i.e., stress) acting on the medium P is reduced compared to a configuration in which the front end sensor 612 and the rear end sensor 614 detect the front end and rear end of the medium P, respectively, when the driven rolls 532, 542 of the transport rolls 530, 540 are positioned in the clamping position.

[0178] (Variation) 4 and 5, in the present embodiment, the detection unit 620 is provided downstream of the abutting roll 560 in the transport direction, but this is not limiting. For example, the detection unit 620 may be configured to be provided upstream of the abutting roll 560 in the transport direction.

[0179] In the present embodiment, the detection unit 620 is divided into a portion that detects one end of the medium P in the width direction and a portion that detects the other end, and the portions are arranged to face each other in the width direction, but this is not limited to this. For example, the detection unit 620 may be configured as a single detection unit that is not divided and extends from one end side to the other end side of the medium P in the width direction.

[0180] In this embodiment, the amount of misalignment in the width direction of the medium P is detected by the side edge sensor 628(A) as an example of one of the detection units of the detection unit 620, but this is not limited to this. For example, a detection unit that detects the amount of misalignment in the width direction of the medium P may be provided separately from the detection unit 620.

[0181] 4 and 5, in the present embodiment, the detection unit 610 is provided on the upstream side of the abutting roll 560 in the transport direction, but this is not limiting. The detection unit 610 may also be configured to be provided on the downstream side of the abutting roll 560 in the transport direction.

[0182] 4, in this embodiment, the distance D1 between the detection element 616(X) located on the most upstream side in the transport direction of the trailing edge sensor 614 and the leading edge sensor 612 is shorter than the length D2 of the maximum size medium P in the transport direction, but this is not limited to this. The distance D1 may be longer than the length D2 of the maximum size medium P in the transport direction.

[0183] 6 , in this embodiment, the leading end sensor 612 and the trailing end sensor 614 each detect the leading end and the trailing end of the medium P being transported by the transport roll 550, which transports the medium P at a constant speed and a transport speed slower than the transport speed upstream of the leading end sensor 612 in the transport direction, but this is not limited to this. For example, the leading end sensor 612 and the trailing end sensor 614 may each detect the leading end and the trailing end of the medium P being transported by a transport unit that transports the medium P while gradually reducing the transport speed from the transport speed upstream of the leading end sensor 612 in the transport direction. Furthermore, the medium P does not need to be transported at a constant speed, as long as the deceleration of the medium P between the time when the detection unit 610 detects the leading end and the trailing end of the medium P is smaller than the deceleration at the times before and after the detection of the leading end and the trailing end of the medium P by the detection unit 610.

[0184] 6, in this embodiment, the leading end sensor 612 and the trailing end sensor 614 each detect the leading end and the trailing end of the medium P when the driven rolls 532, 542 of the transport rolls 530, 540 are positioned in the separated position, but this is not limited to this. For example, the leading end sensor 612 and the trailing end sensor 614 may each be configured to detect the leading end and the trailing end of the medium P when the driven rolls 532, 542 of the transport rolls 530, 540 are positioned in the sandwiched position.

[0185] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit of the present invention. For example, the above-described modified examples may be appropriately combined to form a configuration. [Explanation of symbols]

[0186] 500 Detection Device 530, 540 transport rolls (an example of the upstream transport section) 550 Transport roll (an example of a transport section) 560 Abutting roll (an example of the abutting part) 610 detection unit (an example of a first detection unit) 612 Front end sensor (an example of a front end detection part) 614 Rear end sensor (an example of a rear end detection unit) 620 detection unit (an example of a second detection unit)

Claims

1. a first detector for detecting a leading edge and a trailing edge of the medium being conveyed; a second detection unit that detects both ends of the medium in a direction perpendicular to the conveyance direction of the medium being conveyed, the second detection unit being detected by the first detection unit; Equipped with The first detection unit a leading edge detection unit that detects the leading edge of the medium being conveyed; a trailing edge detection unit having a plurality of detection elements arranged along the transport direction and configured to detect the trailing edge of the medium being transported, wherein the distance between the detection element arranged on the most upstream side of the transport direction and the leading edge detection unit is shorter than the length of a maximum-sized medium in the transport direction; have Detection device.

2. a conveying unit that conveys the medium; an abutment portion that is provided downstream in the transport direction relative to the transport portion and against which the front end of the medium transported by the transport portion abuts; Equipped with The second detection unit is provided downstream of the abutment unit in the conveying direction. The detection device according to claim 1 .

3. The second detection unit is divided into a portion for detecting one end of the medium in the orthogonal direction and a portion for detecting the other end, and is arranged to face each other in the orthogonal direction.

3. The detection device according to claim 1 or 2.

4. At least one of the second detection units arranged in the orthogonal direction detects the amount of positional deviation in the orthogonal direction of the medium. The detection device according to claim 3 .

5. an abutting portion against which the front end of the medium abuts; Equipped with The first detection unit is provided on the upstream side of the abutting unit in the conveying direction. The detection device according to any one of claims 1 to 4.

6. Two sets of the front end detection unit and the rear end detection unit are arranged so as to overlap when viewed in the conveying direction. The detection device according to any one of claims 1 to 5.

7. The conveying unit conveys the medium at a conveying speed that is slower than a conveying speed on the upstream side of the leading end detection unit in the conveying direction, and at a constant speed; The leading edge detector and the trailing edge detector detect the leading edge and the trailing edge of the medium being transported by the transport unit, respectively. The detection device according to claim 2 and any one of claims 3 to 6 dependent on claim 2.

8. An upstream conveying section that is movable between a clamping position where the medium is clamped and a separated position where the medium is separated from the clamping position, and that conveys the medium while positioned at the clamping position, and that is arranged upstream in the conveying direction relative to the conveying section. Equipped with Each of the front end detection unit and the rear end detection unit detects whether the upstream transport unit is in the separated position. and detecting the leading edge and the trailing edge of the medium in this state. The detection device according to claim 2 and any one of claims 3 to 7 dependent on claim 2.

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