Detection device and image forming device

Abstract

To improve detection accuracy of a front end and a rear end of a medium, compared to the case where the front end and the rear end of the medium during conveyance on a conveyance path is detected.SOLUTION: A detection device includes: a conveyance path on which a medium is conveyed; and a detection part for detecting a front end and a rear end of the medium in the state where the conveyance is stopped on the conveyance path and the ends are pulled in a tensile direction along the conveyance path.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a detection device and an image forming apparatus. [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 improve the accuracy of detecting the leading and trailing edges of a medium compared to when the leading and trailing edges of a medium are detected while being transported along a transport path. [Means for solving the problem]

[0006] The first aspect includes a transport path along which a medium is transported, and a detection unit that detects the leading and trailing ends of the medium in the transport path when transport is stopped and the medium is pulled in a pulling direction along the transport path.

[0007] The second aspect includes an upstream conveying section that conveys the medium in the conveying direction on the conveying path and stops the conveying, and a downstream conveying section that is arranged downstream in the conveying direction from the upstream conveying section and conveys the medium in the conveying direction on the conveying path and stops the conveying, and the upstream conveying section and the downstream conveying section pull the medium in the pulling direction.

[0008] In a third aspect, the downstream transport unit transports the medium together with the upstream transport unit, and stops transporting after the upstream transport unit stops transporting, thereby pulling the medium in the pulling direction together with the upstream transport unit.

[0009] In a fourth aspect, the upstream transport section or the downstream transport section has a first transport section and a second transport section arranged upstream of the first transport section in the transport direction.

[0010] In a fifth aspect, the second conveying section of the downstream conveying section pulls a medium whose length in the conveying direction is less than a predetermined length together with the upstream conveying section, and the first conveying section pulls a medium whose length in the conveying direction is equal to or greater than the predetermined length together with the upstream conveying section.

[0011] In a sixth aspect, the first transport section and the second transport section are rolls rotated by a common drive source.

[0012] In a seventh aspect, the upstream transport unit or the downstream transport unit changes the tensile force depending on the characteristics of the medium.

[0013] In the eighth aspect, the upstream conveying section or the downstream conveying section stops so that the amount of protrusion of the end of the medium from the upstream conveying section or the downstream conveying section is approximately the same regardless of the length of the medium in the conveying direction, and the medium is re-conveyed from the end side that has reached the approximately same protrusion amount.

[0014] In a ninth aspect, the detection unit detects the leading and trailing ends of a medium whose length in the transport direction is equal to or greater than a predetermined length when transport is stopped and the medium is pulled in the pulling direction, and does not detect the leading and trailing ends of a medium whose length in the transport direction is less than the predetermined length.

[0015] In a tenth aspect, when the detection unit detects the leading and trailing ends, the detection unit is provided with a side edge detection unit that detects the side edges of the medium, and a support unit that supports the side edges of the medium detected by the side edge detection unit.

[0016] In an eleventh aspect, the support portion is disposed along the side edge detection portion on the upstream side of the side edge detection portion in the transport direction.

[0017] A twelfth aspect includes an image forming unit that forms an image on a medium, a heating unit that heats the medium on which the image has been formed, a transport path along which the heated medium is transported, and a detection unit that detects the leading and trailing ends of the medium in a state where transport has been stopped and the medium is pulled in a pulling direction along the transport path, wherein the image forming unit forms an image again on the heated medium, and the detection unit detects the leading and trailing ends after the medium has been heated and before an image is formed again on the medium.

[0018] A thirteenth aspect includes an image forming unit that forms an image on a medium, a heating unit that heats the medium on which the image has been formed, a transport path along which the heated medium is transported, and a detection unit that detects the front and rear ends of the medium in the transport path when transport has stopped and the medium is pulled in a pulling direction along the transport path, and the detection unit and the heating unit are provided in different parts of a housing that is divided into multiple parts.

[0019] In a fourteenth aspect, the detection unit is provided below the heating unit.

[0020] A fifteenth aspect includes a suction unit that sucks the medium from a medium storage unit that stores the medium, a delivery unit that feeds out the medium sucked by the suction unit, a detection unit that detects the leading and trailing ends of the medium in a state where transportation has stopped and the medium is pulled in a pulling direction along the transportation path along which the medium delivered by the delivery unit is transported, and an image forming unit that forms an image on the medium detected by the detection unit, wherein the detection unit detects the leading and trailing ends of the medium when the leading and trailing ends pass through the delivery unit and are positioned between the delivery unit and the image forming unit.

[0021] A 16th aspect includes a transport path along which multiple types of media are transported, a detection device that detects the leading and trailing ends of the multiple types of media in a state where transport is stopped and the media is pulled in a pulling direction along the transport path, and an image forming unit that forms images on the multiple types of media based on the detection results of the detection device, and the detection device changes the pulling force depending on the type of media. [Effects of the Invention]

[0022] According to the configuration of the first aspect, the accuracy of detecting the leading and trailing edges of the medium is improved compared to when the leading and trailing edges of the medium are detected while being transported along the transport path.

[0023] According to the configuration of the second aspect, the number of parts is reduced compared to when the upstream transport section and the downstream transport section only have the function of transporting the medium.

[0024] According to the configuration of the third aspect, the total operating time for stopping and pulling is reduced compared to when the upstream conveying unit and the downstream conveying unit simultaneously stop conveying the medium, and then at least one of the upstream conveying unit and the downstream conveying unit operates to pull the medium.

[0025] According to the configuration of the fourth aspect, the degree of freedom in the position where the medium is pulled is higher than when the upstream transport section or the downstream transport section has only a single transport section.

[0026] According to the configuration of the fifth aspect, even for media whose length in the transport direction is equal to or greater than a predetermined length, bending at the front end portion of the media whose length in the transport direction is equal to or greater than a predetermined length is suppressed compared to when the second transport section pulls the media together with the upstream transport section.

[0027] According to the configuration of the sixth aspect, the number of parts is reduced compared to when the first transport section and the second transport section are rolls rotated by separate drive sources.

[0028] According to the configuration of the seventh aspect, wrinkles in the medium are suppressed compared to when the tensile force of the upstream transport section or the downstream transport section is constant.

[0029] According to the configuration of the eighth aspect, the amount by which the end of the medium protrudes from the upstream conveying section or the downstream conveying section varies depending on the medium, and conveying control when re-conveying the medium is simplified compared to when the medium is re-conveyed from the protruding side.

[0030] According to the configuration of the ninth aspect, the number of times the detection unit detects the leading and trailing edges of the medium is reduced compared to when the detection unit always detects the leading and trailing edges of the medium regardless of the length of the medium in the transport direction.

[0031] According to the configuration of the 10th aspect, the detection accuracy of the side edges of the medium is improved when the detection unit detects the leading and trailing edges of the medium compared to when the detection unit does not have a support unit that supports the side edges.

[0032] According to the configuration of the eleventh aspect, the accuracy of detecting the side edge of the medium is improved compared to when the support section is disposed downstream in the transport direction from the side edge detector.

[0033] According to the configuration of the 12th aspect, the accuracy of detecting the leading and trailing ends of a medium is improved, even for a medium that is re-transported to an image forming section after heating, compared to detecting the leading and trailing ends of a medium while it is being transported in the transport path.

[0034] According to the configuration of the thirteenth aspect, the influence of heat from the heating unit on the detecting unit is reduced compared to when the detecting unit and the heating unit are provided in the same part of the housing.

[0035] According to the configuration of the fourteenth aspect, the influence of heat from the heating unit on the detecting unit is reduced compared to when the detecting unit is provided above the heating unit.

[0036] According to the configuration of the fifteenth aspect, the influence of suction from the suction unit on the detection unit is reduced compared to when the detection unit detects the leading and trailing edges of the medium using the suction unit.

[0037] According to the configuration of the 16th aspect, it is possible to form an appropriate image for each type of media, compared to a method in which multiple types of media are pulled with a constant tensile force and image formation is performed based on the results of detecting the leading and trailing ends of multiple types of media. [Brief explanation of the drawings]

[0038] [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] FIG. 1 is a perspective view showing a configuration of a detection device according to an embodiment of the present invention. [Figure 5] 1 is a perspective view showing a state in which a first unit and a second unit in the detection device according to the present embodiment are removed from the detection device main body. FIG. [Figure 6] FIG. 1 is a plan view showing a configuration of a detection device according to an embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view for explaining positioning at the rear of the detection device according to the embodiment. [Figure 8] FIG. 10 is a perspective view for explaining positioning at the front of the detection device according to the present embodiment. [Figure 9] 10 is a cross-sectional view for explaining positioning at the front part of the detection device according to the embodiment. FIG. [Figure 10] 5 is a perspective view showing a state in which the opening / closing unit has been moved to an open position in the configuration shown in FIG. 4. FIG. [Figure 11] 2 is a perspective view of a detection device main body of the detection device according to the present embodiment, viewed from below. FIG. [Figure 12] FIG. 2 is an enlarged plan view showing a part of the configuration of the detection device according to the present embodiment. [Figure 13] 12. FIG. 13 is a cross-sectional view taken along line AA in FIG. 6 and a cross-sectional view taken along line AA in FIG. [Figure 14] FIG. 2 is a block diagram illustrating an example of a hardware configuration of one control device according to the present embodiment. [Figure 15] FIG. 2 is a block diagram showing an example of the functional configuration of a processor of one control device according to the present embodiment. [Figure 16] FIG. 2 is a side cross-sectional view of the detection device according to the present embodiment. [Figure 17] FIG. 2 is a side cross-sectional view of the detection device according to the present embodiment. [Figure 18] FIG. 10 is a block diagram showing an example of a hardware configuration of another control device according to the present embodiment. [Figure 19]FIG. 10 is a block diagram showing an example of a functional configuration of a processor of another control device according to the present embodiment. [Figure 20] FIG. 4 is a diagram showing a timing chart in the detection device according to the present embodiment. [Figure 21] 10A and 10B are conceptual diagrams for explaining a method for measuring the length of a medium in the transport direction in the detection device according to the present embodiment. [Figure 22] 22 is a diagram showing a state in which the medium is bent in the configuration shown in FIG. 21. FIG. [Figure 23] 10A and 10B are conceptual diagrams for explaining a method for measuring the length in the transport direction and the length in the width direction of a medium in the detection device according to the present embodiment. [Figure 24] FIG. 10 is a schematic diagram illustrating a configuration of an image forming apparatus using a delivery mechanism having a suction section. [Figure 25] FIG. 10 is a schematic diagram showing the configuration of a delivery mechanism having a suction section. DETAILED DESCRIPTION OF THE INVENTION

[0039] An example of an embodiment of the present invention will be described below with reference to the drawings.

[0040] (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.

[0041] 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."

[0042] 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).

[0043] 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.

[0044] 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 30, and a control device 160.

[0045] 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.

[0046] (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.

[0047] 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.

[0048] 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 of the medium P along the width direction is referred to as the width direction length.

[0049] 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.

[0050] (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 container 12, the image forming unit 14, the heating unit 19, the conveying mechanism 20, and the detection device 30 are arranged inside the image forming apparatus main body 11. The image forming apparatus main body 11 has a housing 18 divided into multiple portions 18A and 18B. The medium container 12, the image forming unit 14, and the heating unit 19 are arranged in the portion 18A of the housing 18. The detection device 30 is arranged in the portion 18B of the housing 18.

[0051] The detection device 30 is removably disposed in the image forming apparatus main body 11. In other words, the detection device 30 is detachable from the image forming apparatus main body 11. The arrangement of the detection device 30 will be described later.

[0052] (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.

[0053] (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.

[0054] (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.

[0055] 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.

[0056] 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.

[0057] (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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] (Heating section 19) 1 is an example of a heating unit that heats a medium P on which an image has been formed. As an example, the heating unit 19 heats the medium P without contacting the medium P using a heat source (not shown), thereby drying the ink image.

[0062] 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.

[0063] 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.

[0064] (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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] (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 a first image (hereinafter sometimes referred to as the "front image") is formed by the image forming unit 14 on one side (i.e., the front side) of the medium P. 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.

[0070] On the other hand, when forming images on both sides of the medium P, the medium P with the front image formed on one side passes through the heating unit 19 and is transported along the transport path 24, where it is turned over and returned to the image forming unit 14 (specifically, the transfer position TA). Then, the image forming unit 14 forms a second image (hereinafter sometimes referred to as a "back side image") on the other side (i.e., the back side) of the heated medium P. In other words, the image forming unit 14 forms an image again. The medium P is then discharged to the medium discharge unit 13 via the heating unit 19.

[0071] (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.

[0072] 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.

[0073] (Detection device 30) The detection device 30 shown in Fig. 1 is an example of a detection device that detects the edge of a medium P. Fig. 4 is a perspective view showing the configuration of the detection device 30. Fig. 5 is a perspective view showing the state in which the first unit 31 and the second unit 32 of the detection device 30 are removed from the detection device main body 40. Fig. 6 is a plan view showing the configuration of the detection device 30.

[0074] Here, in the detection device 30, "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.

[0075] 4 and 5, the detection device 30 includes a detection device main body 40, a first unit 31, a second unit 32, an opening / closing section 70, a conveying section 80 (see FIG. 1), front and rear end detection sections 90, side end detection sections 98, a presser member 110 (see FIGS. 12 and 13), a presser member 120 (see FIG. 6), and a rear end sensor 99. The shape of the detection device 30 and the configuration of each section of the detection device 30 will be described below. Furthermore, the control device 160, the arrangement of the detection device 30 in the image forming device 10, and removal of the detection device 30 from the image forming device main body 11 will be described.

[0076] (Shape of the detection device 30) As shown in FIG. 4, the detection device 30 is longer in the left-right direction (corresponding to the length in the transport direction) and the front-rear direction (corresponding to the length in the width direction) than in the up-down direction. That is, the detection device 30 is formed in a flat shape that is thin in the up-down direction and spreads in the front-rear and left-right directions (specifically, the horizontal direction). Furthermore, since the detection device 30 transports a medium P of size A3+ or larger, it has a size of at least A3+ or larger in plan view. The shape of the detection device 30 is not limited to a flat shape and can be various shapes.

[0077] (Detection device main body 40) 5, the detection device main body 40 is formed in a flat shape that is thin in the vertical direction and wide in the front-rear and left-right directions, similar to the overall shape of the detection device 30. Specifically, the detection device main body 40 has a plate body 41, a front plate 42, a rear plate 43, and a guide plate 44. The detection device main body 40 is formed, for example, from a metal material such as sheet metal, a resin material, or other materials.

[0078] The plate body 41 is formed in a plate shape that extends in the front-rear and left-right directions and has a thickness in the up-down direction. The upper surface of this plate body 41 serves as a conveying path surface 41A. The plate body 41 is formed with a plurality of openings 41B in which roll sections 842, 852, and 862, which will be described later, are disposed. In this embodiment, as an example, twelve openings 41B are formed. A plurality of reflecting plates 97, which will be described later, are disposed on the upper surface of the plate body 41. In this embodiment, as an example, eight reflecting plates 97 are disposed.

[0079] The front plate 42 is a plate that protrudes downward from the front end of the plate body 41 and is formed integrally with the plate body 41. The front plate 42 is formed in a plate shape with its thickness direction extending in the front-to-rear direction. The front plate 42 rotatably supports drive rolls 84, 85, and 86, which will be described later (see FIG. 11).

[0080] The front plate 42 is provided with a support portion 42A that supports the opening / closing portion 70. The support portion 42A is formed by cutting and raising a part of the plate body 41, for example.

[0081] The rear plate 43 is a plate that protrudes upward from the rear end of the plate body 41 and is formed integrally with the plate body 41. The rear plate 43 is formed in a plate shape with its thickness direction in the front-to-rear direction. As will be described later, the rear plate 43 functions as a positioning portion that positions the first unit 31 and the second unit 32. The rear plate 43 is formed with a plurality of insertion holes 45E into which protrusions 51E (described later) are inserted and a plurality of insertion holes 46E into which protrusions 61E (described later) are inserted. In this embodiment, as an example, two insertion holes 45E are formed, and in this embodiment, as an example, three insertion holes 46E are formed. The insertion holes 45E and the insertion holes 46E are elongated holes that are elongated in the left-right direction.

[0082] The guide plate 44 is connected to the right end of the plate body 41. It extends diagonally upward to the right from the right end of the plate body 41. The guide plate 44 has the function of guiding the medium P toward the plate body 41 (i.e., the left side). An opening 44B is formed at the lower end of the guide plate 44, through which the medium P passes as it is transported from the plate body 41 to the right side (i.e., in the second transport direction described below). The guide plate 44 has a relatively small curvature. Specifically, the curvature of the guide plate 44 is smaller than the curvature of the transport path 25, for example. Therefore, the medium P transported along the guide plate 44 is less likely to bend. As a result, the medium P and the image formed on the medium P are less likely to be scratched by rubbing against the guide plate 44.

[0083] (First Unit 31) 4 and 5, the first unit 31 is disposed on the upper side of the detection device main body 40. Specifically, the first unit 31 is disposed on the upper side of the left portion of the detection device main body 40. More specifically, the first unit 31 constitutes the upper left portion of the detection device 30.

[0084] The first unit 31 has a unit main body 50 and a substrate support section 59. The first unit 31 is further provided with driven rolls 87 and 88 (described later) of the conveying section 80, and sensors 91(A), 92(A), and 93(A)(B) and sensor substrates 95(A), 95(B), 95(C), and 95(D) (described later) in the front and rear end detection section 90 and the side end detection section 98. The first unit 31 is formed of, for example, a metal material such as sheet metal, a resin material, or other materials.

[0085] As shown in FIG. 5, the unit body 50 includes a plate 51, a front plate 52, a rear plate 53, a left plate 54, and a right plate 55. The plate 51 is formed like a plate extending in the front-rear and left-right directions and having a thickness in the up-down direction. The lower surface of the plate 51 serves as a conveying path surface 51A (see FIGS. 5, 7, and 13). The plate 51 is formed with an opening 51B in which driven rolls 87 and 88 are disposed, and an opening 51C (see FIG. 6) in which sensors 91(A), 92(A), and 93(A)(B) are disposed. The plate 51 is disposed above the plate 41 of the detection device body 40, facing the plate 41 with a gap between them (see FIGS. 7 and 13).

[0086] The front plate 52 is a plate that protrudes upward from the front end of the plate body 51. The rear plate 53 is a plate that protrudes upward from the rear end of the plate body 51. The front plate 52 and the rear plate 53 are formed in a plate shape with the thickness direction extending in the front-to-rear direction.

[0087] The left plate 54 is a plate that protrudes upward from the left end of the plate body 51. The right plate 55 is a plate that protrudes upward from the right end of the plate body 51. The left plate 54 and the right plate 55 are formed in a plate shape with the thickness direction extending in the left-right direction.

[0088] As shown in Figures 5, 6, and 7(A) and (B), a protrusion 51E is provided at the rear end of the plate body 51, which is inserted into the insertion hole 45E of the rear plate 43 of the detection device main body 40. This protrusion 51E is disposed on the same plane as the plate body 51 and protrudes rearward relative to the rear plate 53. As one example, the protrusion 51E is formed by cutting and raising a portion of the rear plate 53. At the rear of the first unit 31, as shown in Figures 7(A) and (B), the protrusion 51E is inserted into the insertion hole 45E, and the rear plate 53 abuts against the rear plate 43 of the detection device main body 40.

[0089] 8 and 9, a through hole 51D is formed in the front portion of the plate body 51, through which a fastening member 38 such as a bolt is passed. A plurality of through holes 51D are formed in the left-right direction. Then, in the front portion of the first unit 31, the plate body 51 and the plate body 41 are fastened together by the fastening member 38, with a spacer 39 sandwiched between the plate body 51 of the first unit 31 and the plate body 41 of the detection device main body 40.

[0090] The first unit 31 is positioned relative to the detection device main body 40 in the front-rear direction by the rear plate 53 abutting against the rear plate 43 of the detection device main body 40. Furthermore, the first unit 31 is positioned relative to the detection device main body 40 in the up-down direction and the left-right direction by the protrusion 51E being inserted into the insertion hole 45E and the plate body 51 and the plate body 41 being fastened together by the fastening member 38 via the spacer 39.

[0091] Furthermore, the first unit 31 can be removed from the detection device main body 40 by removing the fastening members 38. That is, the first unit 31 is disposed so as to be removable from the detection device main body 40. Note that, in the present embodiment, as described above, the first unit 31 is attached to the detection device main body 40 by the fastening members 38, but the attachment member for attaching the first unit 31 to the detection device main body 40 is not limited to the fastening members 38. The attachment member may be, for example, a clamp or the like, as long as it is a member that can attach the first unit 31 to the detection device main body 40.

[0092] As shown in Figures 4 and 5, the board support portion 59 is a portion that has the function of supporting a sensor board 95, which will be described later. Specifically, as shown in Figure 5, the board support portion 59 has an attachment plate 59A and a connecting plate 59B. The attachment plate 59A is disposed above the plate body 51. A plurality of sensor boards 95 are attached to the attachment plate 59A. The connecting plate 59B extends downward from the attachment plate 59A and is connected to the plate body 51.

[0093] (Second Unit 32) 4 and 5, the second unit 32 is disposed above the detection device main body 40. Specifically, the second unit 32 is disposed above the right portion of the detection device main body 40. More specifically, the second unit 32 constitutes the right portion of the upper part of the detection device 30. Therefore, the upper part of the detection device 30 can be divided into the first unit 31 and the second unit 32.

[0094] The second unit 32 has a unit main body 60 and a substrate support section 69. The second unit 32 is further provided with a driven roll 89 (to be described later) of the conveying section 80, sensors 91(B), 92(B), 94(A)(B) (to be described later) in the front and rear end detection section 90 and the side end detection section 98, and sensor substrates 95(E), 95(F), 95(G), 95(H) (to be described later). The second unit 32 is formed of, for example, a metal material such as sheet metal, a resin material, or other materials.

[0095] As shown in FIG. 5, the unit body 60 has a plate body 61, a front plate 62, a rear plate 63, a left plate 64, and a right plate 65. The plate body 61 is formed in a plate shape that extends in the front-rear and left-right directions and has a thickness in the up-down direction. The lower surface of the plate body 61 serves as a conveying path surface 61A (see FIGS. 5 and 7). The plate body 61 is formed with an opening 61B in which a driven roll 89 is disposed, and an opening 61C (see FIG. 6) in which sensors 91(B), 92(B), and 94(A)(B) are disposed. The plate body 61 is disposed above the plate body 41 of the detection device body 40, facing the plate body 41 with a gap between them (see FIG. 7).

[0096] The front plate 62 is a plate that protrudes upward from the front end of the plate body 61. The rear plate 63 is a plate that protrudes upward from the rear end of the plate body 61. The front plate 62 and the rear plate 63 are formed in a plate shape with the thickness direction extending in the front-to-rear direction.

[0097] The left plate 64 is a plate that protrudes upward from the left end of the plate body 61. The right plate 65 is a plate that protrudes upward from the right end of the plate body 61 along the guide plate 44. The left plate 64 is formed in a plate shape with its thickness in the left-right direction.

[0098] As shown in Figures 5, 6, and 7(A) and (B), a protrusion 61E is provided at the rear end of the plate body 61 to be inserted into the insertion hole 46E of the rear plate 43 of the detection device main body 40. This protrusion 61E is disposed on the same plane as the plate body 61 and protrudes rearward relative to the rear plate 63. As one example, the protrusion 61E is formed by cutting and raising a portion of the rear plate 63. Then, at the rear of the second unit 32, as shown in Figures 7(A) and (B), the protrusion 61E is inserted into the insertion hole 46E, and the rear plate 63 abuts against the rear plate 43 of the detection device main body 40.

[0099] 9, a through hole 61D is formed in the front portion of the plate 61, through which a fastening member 38 such as a bolt is passed. A plurality of through holes 61D are formed in the left-right direction. Then, in the front portion of the second unit 32, the plate 61 of the second unit 32 and the plate 41 of the detection device main body 40 are fastened to each other by the fastening member 38, with a spacer 39 sandwiched between them.

[0100] The second unit 32 is positioned relative to the detection device main body 40 in the front-rear direction by the rear plate 63 abutting against the rear plate 43 of the detection device main body 40. The second unit 32 is also positioned relative to the detection device main body 40 in the up-down direction and the left-right direction by the protrusion 61E being inserted into the insertion hole 46E and the plate body 61 and the plate body 41 being fastened together by the fastening member 38 via the spacer 39.

[0101] Moreover, the second unit 32 can be removed from the detection device main body 40 by removing the fastening members 38. That is, the second unit 32 is disposed in a detachable manner relative to the detection device main body 40.

[0102] As shown in Figures 4 and 5, the board support part 69 is a part that has the function of supporting a sensor board 95, which will be described later. Specifically, as shown in Figure 5, the board support part 69 has an attachment plate 69A and a connecting plate 69B. The attachment plate 69A is disposed above the plate body 61. A plurality of sensor boards 95 are attached to the attachment plate 69A. The connecting plate 69B extends downward from the attachment plate 69A and is connected to the plate body 61.

[0103] (Opening and closing part 70) As shown in FIGS. 4 and 10, the opening / closing unit 70 has a function of opening and closing an opening 77 that opens the transport path 80A (see FIG. 1) in the transport unit 80. As shown in FIG. 4, the opening / closing unit 70 is disposed above the detection device main body 40, between the first unit 31 and the second unit 32. The opening / closing unit 70 is disposed between the sensors 91(A) and 92(A) provided in the first unit 31 and the sensors 91(A) and 92(B) provided in the second unit 32, at a position where the sensors 91 to 94 are not present. The opening / closing unit 70 is formed, for example, from a metal material such as sheet metal, a resin material, or other materials.

[0104] 4 and 5, the opening / closing unit 70 has a plate body 71, a front plate 72, a rear plate 73, a left plate 74, and a grip part 76. The plate body 71 is formed in a plate shape that extends in the front-rear and left-right directions and has a thickness in the up-down direction. The lower surface of the plate body 71 serves as a transport path surface 71A (see FIG. 10).

[0105] The front plate 72 is a plate that protrudes upward from the front end of the plate body 71. The rear plate 73 is a plate that protrudes upward from the rear end of the plate body 71. The front plate 72 and the rear plate 73 are formed into plate shapes whose thickness direction is the front-to-rear direction. The left plate 74 is a plate that protrudes upward from the left end of the plate body 71. The left plate 74 is formed into a plate shape whose thickness direction is the left-to-right direction.

[0106] 4 and 10, the opening / closing unit 70 is supported by the detection device main body 40 so as to be able to open and close an opening 77 that opens the transport path 80A (see FIG. 1) in the transport unit 80. That is, the opening / closing unit 70 is movable between a closed position (position shown in FIG. 4) where the opening 77 is closed and an open position (position shown in FIG. 10) where the opening 77 is open. Specifically, the right end of the front plate 72 and the right end of the rear plate 73 of the opening / closing unit 70 are rotatably supported by the support portion 42A and the rear plate 43 of the detection device main body 40, respectively.

[0107] In the closed position, the opening / closing unit 70 is disposed above the plate body 41 of the detection device main body 40, facing the plate body 41 with a gap between them. The gripping portion 76 is provided on the front side of the front plate 72 and protrudes forward from the front plate 72. An operator grips the gripping portion 76 to move the opening / closing unit 70 between the closed position and the open position.

[0108] As an example, the opening / closing unit 70 is opened and closed to clear a blockage (so-called jam) of the medium P that has occurred in the transport path 80A (see FIG. 1). The opening / closing unit 70 is not limited to the above-mentioned use, and may be opened and closed for various purposes, such as cleaning the transport path surface 71A and the transport path surface 41A of the transport path 80A (see FIG. 1). Here, it is required that the medium P and the image are not noticeably scratched. Whether or not a noticeable scratch occurs depends on the curvature of the guide plate 44 and the stiffness of the medium P, and noticeable scratches may also occur due to foreign matter that has entered the transport path 80A. Therefore, it is beneficial to be able to open and clean the transport path 80A.

[0109] (Overview of the conveying unit 80) The transport unit 80 shown in FIG. 1 has a transport path 80B along which the medium P is transported, and in the transport path 80B, the transport of the medium P is stopped and the medium P is pulled in a pulling direction along the transport path 80B.

[0110] Conveying path 80B is a path along which medium P heated by heating unit 19 is transported in detection device 30, and is formed by conveying path 80A. Conveying path 80A is a passage formed by conveying path surfaces 41A, 51A, 61A, and 71A. As shown in FIG. 1, conveying path 80A constitutes a part of conveying path 24 from heating unit 19 to image forming unit 14.

[0111] Furthermore, in the conveying unit 80, the conveyance of the medium P on which the front surface image has been formed is stopped, and after the medium P has stopped (i.e., is stationary), conveyance of the medium P is resumed toward the image forming unit 14 (specifically, toward the transfer position TA). Specifically, in the conveying unit 80, the medium P is conveyed to the left (hereinafter, the conveyance direction of the medium P before it has stopped is referred to as the "first conveyance direction"), the leftward conveyance of the medium P is stopped, and after the medium P has stopped, conveyance of the medium P is resumed to the right (hereinafter, the conveyance direction of the medium P after it has stopped is referred to as the "second conveyance direction"). That is, in the conveying unit 80, after the medium P has stopped, conveyance is resumed in a second conveyance direction different from the first conveyance direction. Furthermore, the first conveyance direction and the second conveyance direction are opposite directions. In other words, the conveying unit 80 can be said to switch back the medium P. Thus, in this embodiment, the leftward direction corresponds to the first conveyance direction, and the rightward direction corresponds to the second conveyance direction. Note that the conveying unit 80 conveys one sheet of medium P. Furthermore, the transport unit 80 stops the medium P at a predetermined stopping position.

[0112] As described above, in the transport unit 80, the medium P is transported in the transport direction on the transport path 80B, and then transport of the medium P in the transport direction is stopped. Furthermore, in the transport unit 80, the medium P whose transport has been stopped is pulled in a direction along the transport path 80B (hereinafter referred to as the pulling direction). The pulling direction is a direction that includes the first transport direction and the second transport direction.

[0113] As described above, since the first and second conveying directions are opposite to each other, the upstream side of the first conveying direction can be regarded as the downstream side of the second conveying direction, and the downstream side of the first conveying direction can be regarded as the upstream side of the second conveying direction. Therefore, in the detection device 30, each member arranged on the upstream side of the first conveying direction can be regarded as a member arranged on the downstream side of the second conveying direction, and each member arranged on the downstream side of the first conveying direction can be regarded as a member arranged on the upstream side of the second conveying direction.

[0114] In the description of the detection device 30, the "conveying direction" refers to the "first conveying direction." Therefore, in the description of the detection device 30, the "first conveying direction" may be simply referred to as the "conveying direction."

[0115] (Specific configuration of the conveying unit 80) 16 and 17, the transport unit 80 specifically has an upstream transport unit 80X that transports the medium P in a first transport direction on the transport path 80B and stops the transport, and a downstream transport unit 80Y that is disposed downstream in the transport direction from the upstream transport unit 80X and transports the medium P in the first transport direction on the transport path 80B and stops the transport. Note that in FIGS. 16 and 17, for simplicity of illustration, the transport path surfaces 51A, 61A, and 71A are shown as a single unit.

[0116] The upstream transport section 80X has a transport member 83. The transport member 83 is disposed in an upstream portion of the detection device 30 in the transport direction (specifically, in a portion on the right side).

[0117] The downstream transport unit 80Y has transport members 81 and 82. The transport members 81 and 82 are arranged downstream in the transport direction relative to the transport member 83 (specifically, on the left side). Specifically, the transport member 82 is arranged upstream in the transport direction relative to the transport member 81 and downstream in the transport direction relative to the transport member 83. Each of the transport members 81, 82, and 83 has a function of transporting the medium P in a first transport direction (corresponding to the left) on the transport path 80B and stopping the transport. Furthermore, the transport members 81, 82, and 83 have a function of pulling the medium P in a pulling direction on the transport path 80B. The transport members 81, 82, and 83 have a function of transporting the medium P in a second transport direction (corresponding to the right) on the transport path 80B. The transport members 81 and 82 are an example of a downstream transport unit, and the transport member 83 is an example of an upstream transport unit. Furthermore, the conveying member 81 is an example of a first conveying section, and the conveying member 82 is an example of a second conveying section.

[0118] The transport members 81, 82, 83 each have a driving roll 84, 85, 86 as a rotating member that is rotated to apply a transport force to the medium P, and a driven roll 87, 88, 89 as a driven member that is driven by the driving roll 84, 85, 86, respectively.

[0119] As shown in Fig. 11, the drive rolls 84, 85, and 86 each have a shaft portion 841, 851, and 861, roll portions 842, 852, and 862, and connection portions 843, 853, and 863. The shaft portions 841, 851, and 861 are arranged along the front-rear direction. One axial end portion (specifically, the front end portion) of each of the shaft portions 841, 851, and 861 is rotatably supported by the front plate 42 of the detection device main body 40. The other axial end portion (specifically, the rear end portion) of each of the shaft portions 841, 851, and 861 is rotatably supported by a shaft portion support portion (not shown) provided on the plate body 41 of the detection device main body 40.

[0120] The roll portions 842, 852, 862 are arranged at intervals along the axial direction of the shaft portions 841, 851, 861. Each of the roll portions 842, 852, 862 protrudes upward from the opening 41B of the plate body 41. That is, the roll portions 842, 852, 862 of the drive rolls 84, 85, 86 (i.e., the portions that contact the medium P) protrude upward from the transport path surface 41A of the detection device main body 40. In this embodiment, four roll portions 842, 852, 862 are provided, as indicated by the reference characters (A), (B), (C), and (D) in the drawing.

[0121] The connecting portions 843, 853, and 863 are connected to the connecting portions 743, 753, and 763, which rotate by driving force from driving sources 777 and 778, such as motors. The connecting portions 843, 853, and 863 and the connecting portions 743, 753, and 763 are configured as shaft joints (also referred to as couplings) that are axially connected to each other. The driving force from the driving source 777 is transmitted to the connecting portions 743 and 753 via transmission members such as gears (not shown). As a result, the conveying member 81, which includes the driving roll 84 and the driven roll 87, and the conveying member 82, which includes the driving roll 85 and the driven roll 88, are rotated by the common driving source 777. On the other hand, the driving force from the driving source 778 is transmitted to the connecting portion 763 via transmission members such as gears (not shown). As a result, the conveying member 83, which includes the driving roll 86 and the driven roll 89, is rotated by the driving source 778. The control device 160 functions as a control unit that controls the driving of the driving sources 777 and 778 .

[0122] In the present embodiment, as an example, the connection portions 743, 753, 763, the drive sources 777, 778, and the control device 160 are provided in the image forming apparatus main body 11. That is, in the present embodiment, the connection portions 743, 753, 763, the drive sources 777, 778, and the control device 160 are understood to be not components of the detection device 30. In this manner, the drive rolls 84, 85, 86 are rotated by the drive forces of the drive sources 777, 778 arranged in the image forming apparatus main body 11 being transmitted to the roll portions 842, 852, 862 via the shaft portions 841, 851, 861 by connecting the connection portions 843, 853, 863 to the connection portions 743, 753, 763 arranged in the image forming apparatus main body 11.

[0123] 4 and 5, a plurality of driven rolls 87, 88, 89 are provided. Specifically, the number of driven rolls 87, 88, 89 is the same as the number of roll portions 842, 852, 862. In this embodiment, four driven rolls 87, 88, 89 are provided, as indicated by the reference characters (A), (B), (C), and (D) in the drawings.

[0124] Each of the driven rolls 87, 88, and 89 is disposed opposite one of the roll sections 842, 852, and 862. That is, a plurality of each of the driven rolls 87, 88, and 89 (four in this embodiment) are disposed along the front-to-rear direction. The reference symbols (A), (B), (C), and (D) assigned to each of the driven rolls 87, 88, and 89 are assigned in this order from the roll disposed on the front side to the roll disposed on the rear side.

[0125] Each of the driven rolls 87(A) and 87(B), and the driven rolls 88(A) and 88(B) is arranged with a sensor 93(A) (described later) sandwiched between them in the front-to-back direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0126] Roll section 842(A) and roll section 842(B), and roll section 852(A) and roll section 852(B), are each arranged in the front-to-back direction, sandwiching sensor 93(A), which will be described later, when viewed in a direction perpendicular to the image forming surface of medium P.

[0127] Specifically, the driven rolls 87(A) and 87(B) and the roll portions 842(A) and 842(B) each sandwich a left side portion of a sensor 93(A) (described later) in the front-to-rear direction. The driven rolls 88(A) and 88(B) and the roll portions 852(A) and 852(B) each sandwich a right side portion of a sensor 93(A) (described later) in the front-to-rear direction.

[0128] Each of the driven rolls 87(C) and 87(D), and the driven rolls 88(C) and 88(D) is arranged with the sensor 93(B) described below sandwiched between them in the front-to-back direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0129] Roll section 842(C) and roll section 842(D), and roll section 852(C) and roll section 852(D), are each arranged in the front-to-back direction, sandwiching sensor 93(B), which will be described later, when viewed in a direction perpendicular to the image forming surface of medium P.

[0130] Specifically, the driven rolls 87(C) and 87(D) and the roll portions 842(C) and 842(D) each sandwich a left portion of a sensor 93(B) (described later) in the front-to-rear direction. The driven rolls 88(C) and 88(D) and the roll portions 852(C) and 852(D) each sandwich a right portion of a sensor 93(B) (described later) in the front-to-rear direction.

[0131] The driven rolls 89(A) and 89(B) and the roll portions 862(A) and 862(B) are each arranged, when viewed in a direction perpendicular to the image forming surface of the medium P, with the sensor 94(A) described below sandwiched between them in the front-to-back direction.

[0132] The driven rolls 89(C) and 89(D) and the roll portions 862(C) and 862(D) are each arranged on either side of the sensor 94(B) described below in the front-to-back direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0133] As described above, in this embodiment, the driven rolls 87, 88, 89 and the roll sections 842, 852, 862 are appropriately arranged to sandwich the sensors 93, 94 in the front-to-back direction (i.e., the width direction of the medium P) when viewed in a direction perpendicular to the image forming surface of the medium P.

[0134] Each of the driven rolls 87, 88 is disposed in the first unit 31, as shown in Fig. 5. Each of these driven rolls 87, 88 is rotatably supported by the plate body 51 so that its outer circumferential surface (i.e., the surface that contacts the medium P) protrudes downward from the opening 51B of the plate body 51 of the first unit 31, as shown in Fig. 13. That is, each of the driven rolls 87, 88 has its outer circumferential surface protruding downward from the transport path surface 51A of the first unit 31, and is in contact with each of the roll portions 842, 852.

[0135] The driven rolls 89 are disposed in the second unit 32. Specifically, each of the driven rolls 89, similar to the driven rolls 87 and 88, is rotatably supported by the plate body 61 such that its outer circumferential surface (i.e., the surface that contacts the medium P) protrudes downward from the opening 61B of the plate body 61 of the second unit 32. That is, the outer circumferential surface of the driven roll 89 protrudes downward from the transport path surface 61A of the plate body 61 and is in contact with the roll portion 862.

[0136] In the transport section 80, the drive rolls 84, 85, and 86 and the driven rolls 87, 88, and 89 each sandwich the medium P, and as the drive rolls 84, 85, and 86 are driven to rotate, a transport force is applied to the medium P, and the medium P is transported along the transport path 80B.

[0137] In addition, the conveying unit 80 conveys the medium P in the first conveying direction and the medium P in the second conveying direction along the conveying path 80B by changing the rotation direction of the conveying members 81, 82, and 83. Furthermore, the conveying unit 80 creates a state in which the conveyance of the medium P is stopped and the medium P is pulled in a pulling direction along the conveying path 80B (hereinafter, sometimes referred to as a "pulled state") between the conveyance of the medium P in the first conveying direction and the conveyance of the medium P in the second conveying direction. Here, the "pulled state" of the medium P refers to a state in which both one side and the other side of the stopped medium P are not in contact with the conveying path, as well as a state in which at least one of the one side and the other side of the stopped medium P is not in contact with the conveying path. The operation of the conveying unit 80 is controlled by the control device 160. Specific conveying operations in the conveying unit 80 will be described later.

[0138] Furthermore, the transport unit 80 has transport path surfaces 41A, 51A, 61A, and 71A that face one side and the other side of the medium P in the tensioned state, respectively (see FIG. 1). As described above, the transport path surface 41A is formed by the upper surface of the plate body 41 of the detection device main body 40 (see FIGS. 5 and 13), and faces the lower surface of the medium P in the tensioned state, guiding the lower surface of the medium P.

[0139] The transport path surface 41A is flat across the entire surface of the medium P. Specifically, the transport path surface 41A is flat across the entire surface of the maximum-sized medium P used in the image forming apparatus 10. Furthermore, the transport path surface 41A is formed larger than the maximum-sized medium P in the transport direction and width direction. The transport path surface 41A may have partial irregularities. The transport path surface 41A may have partial convex portions, for example, by providing a member such as a reflector 97 or by having members such as roll portions 842, 852, and 862 protrude. The transport path surface 41A may also have partial concave portions, for example, by forming holes such as the opening 416B, grooves, or recesses. The transport path surface 41A may also have a structure that reduces the contact area with the medium P by having at least one of concave and convex portions, for example, by forming ribs or drawing a metal plate. Thus, the above-mentioned "flat surface" includes a flat surface having partial irregularities.

[0140] As described above, the transport path surface 51A is formed by the underside of the plate body 51 of the first unit 31 (see Figures 7 and 13), and faces the upper surface of the medium P in the tensioned state, guiding the upper surface of the medium P. As described above, the transport path surface 61A is formed by the underside of the plate body 61 of the second unit 32 (see Figure 7), and faces the upper surface of the medium P in the tensioned state, guiding the upper surface of the medium P. As described above, the transport path surface 71A is formed by the underside of the plate body 71 of the opening / closing section 70 (see Figure 10), and faces the upper surface of the medium P in the tensioned state, guiding the upper surface of the medium P.

[0141] The road surface above the medium P in the tensioned state, which is formed by the transport road surfaces 51A, 61A, and 71A, is flat over the entire surface of the medium P. Specifically, this road surface is flat over the entire surface of the maximum size medium P used in the image forming device 10.

[0142] As described above, the transport members 81 and 82 have the function of transporting the medium P, but they can also be understood as support portions that support the medium P transported by the transport member 83. Specifically, the drive rolls 84 and 85 support the underside of the medium P with roll portions 842 and 852 that protrude upward relative to the transport path surface 41A of the detection device main body 40. The driven rolls 87 and 88 press the medium P against the drive rolls 84 and 85 with their outer peripheral surfaces that protrude downward relative to the transport path surface 51A of the first unit 31.

[0143] In this way, in the transport section 80, the drive rolls 84 and 85 support the lower surface of the medium P at a position above the transport path surface 41A of the detection device main body 40 (ie, at a position away from the transport path surface 41A).

[0144] Conveying members 81 and 82 are arranged at a plurality of positions corresponding to media P with different lengths in the conveying direction. Specifically, conveying member 81 is arranged at a position where it can support the lower end side in the conveying direction of a medium P of the maximum size (specifically, the longest length in the conveying direction) used in image forming apparatus 10. Conveying member 82 is arranged at a position where it can support the lower end side in the conveying direction of a medium P of the minimum size (specifically, the shortest length in the conveying direction) used in image forming apparatus 10.

[0145] Furthermore, in the conveying section 80, the distance between the conveying member 82 of the downstream conveying section 80Y and the upstream conveying section 80X (specifically, the conveying member 83) is greater than the distance between the conveying member 81 and the conveying member 82 in the downstream conveying section 80Y.

[0146] (Rear end sensor 99) The trailing end sensor 99 is a detection unit that detects the trailing end of the medium P. The trailing end sensor 99 is disposed on the upstream side in the transport direction relative to the transport member 83. In other words, the trailing end sensor 99 detects the trailing end of the medium P on the upstream side in the transport direction relative to the transport member 83.

[0147] Specifically, the trailing edge sensor 99 is a non-contact sensor that detects the trailing edge of the medium P without coming into contact with the medium P. Even more specifically, the trailing edge sensor 99 is an optical sensor that uses light that is irradiated toward the medium P. Even more specifically, the trailing edge sensor 99 is a reflective optical sensor that detects the trailing edge of the medium P by detecting reflected light of light that is irradiated onto the medium P. Note that a transmissive optical sensor may also be used as the trailing edge sensor 99.

[0148] In this embodiment, as will be described later, each part of the transport unit 80 is operated based on the timing when the trailing edge sensor 99 detects the trailing edge of the medium P.

[0149] (Control device 160) Here, the configuration of the control device 160 will be described. The control device 160 has a control function for controlling the operation of the image forming apparatus 10 including the detection device 30. In this embodiment, the control device 160 controls the operation of the conveying unit 80 of the detection device 30. Specifically, as shown in FIG. 18 , the control device 160 has a processor 161, a memory 162, a storage 163, and a timer 164.

[0150] 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.).

[0151] The storage 163 stores various programs including a control program 163A (see FIG. 19) 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.

[0152] 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 first, second, and third elapsed times, which will be described later.

[0153] 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 19 is a block diagram showing the functional configuration of the processor 161.

[0154] 19, in the control device 160, the processor 161 executes the control program 163A to function as an acquisition unit 161A and a control unit 161C. The acquisition unit 161A acquires detection information indicating that the rear end of the medium P has been detected by the rear end sensor 99.

[0155] The control unit 161C controls the transport unit 80 (specifically, the drive sources 777 and 778) to perform the transport operation described below.

[0156] 20, in the transport section 80, the drive rolls 84, 85, and 86 are rotationally driven to rotate in the forward direction (counterclockwise in FIG. 16), and the driven rolls 87, 88, and 89 are driven to rotate in the forward direction (clockwise in FIG. 16), thereby transporting the medium P in the first transport direction (corresponding to the left).

[0157] Next, after the first elapsed time has elapsed since the trailing edge sensor 99 detected the trailing edge of the medium P, the drive roll 86 and the driven roll 89 stop rotating (specifically, start to stop rotating).

[0158] Next, after a second elapsed time has elapsed since the drive roll 86 and the driven roll 89 stopped rotating (specifically, since they started to stop rotating), the drive rolls 84, 85 and the driven rolls 87, 88 also stop rotating (specifically, since they started to stop rotating). This brings the medium P to a stopped state. In this way, the drive roll 86 and the driven roll 89, and the drive rolls 84, 85 and the driven rolls 87, 88 stop rotating with a time difference, and the medium P is pulled in the pulling direction. That is, the medium P is stopped from being transported in the transport path 80B and is pulled in the pulling direction.

[0159] Then, after a third elapsed time has elapsed since the drive rolls 84 and 85 stopped rotating (specifically, since they started to stop rotating), the drive rolls 84, 85, and 86 rotate in the reverse direction (clockwise in FIG. 16), and the driven rolls 87, 88, and 89 rotate in the reverse direction (counterclockwise in FIG. 16), thereby transporting the medium P in the second transport direction (corresponding to the right).

[0160] In this way, in the conveying unit 80, the conveying members 81, 82, and 83 (drive rolls 84, 85, and 86 and driven rolls 87, 88, and 89) convey the medium P in the first conveying direction and then stop the conveying. Furthermore, after the conveying member 83 stops conveying the medium P, the conveying members 81 and 82 also stop conveying the medium P, causing the conveying members 81, 82, and 83 to pull the medium P in the pulling direction. Then, the ends of the medium P in the pulled state (specifically, the front and rear ends and a pair of side ends) are detected by the front and rear end detection unit 90 and the side end detection unit 98, as described below.

[0161] Since the conveying members 81 and 82 are driven by a common driving source 777, the conveying member 81 rotates (forward and reverse) and stops together with the conveying member 82.

[0162] As described above, in this embodiment, the rotation of the transport member 83 is stopped based on the detection timing when the rear end sensor 99 detects the rear end of the medium P, and the transport member 83 stops transporting the medium P so that the amount by which the rear end of the medium P protrudes from the transport member 83 upstream in the transport direction becomes approximately the same regardless of the length of the medium P in the transport direction. Furthermore, the transport members 81, 82, and 83 re-transport the medium P from the end side where the amount of protrusion has become approximately the same (i.e., the upstream end side in the transport direction (specifically, the right end side)).

[0163] FIG. 16 shows the stopping positions on the transport path 80B where the smallest size medium P stops, and FIG. 17 shows the stopping positions on the transport path 80B where the largest size medium P stops.

[0164] At this stop position, the upstream portion of the smallest-sized medium P in the transport direction is sandwiched between the drive roll 86 and the driven roll 89, and the downstream portion in the transport direction is sandwiched between the drive roll 85 and the driven roll 88. Therefore, the transport member 82 (drive roll 85 and driven roll 88) pulls the smallest-sized medium P together with the transport member 83 (drive roll 86 and driven roll 89).

[0165] At the stop position, the upstream portion of the maximum-sized medium P in the transport direction is sandwiched between the drive roll 86 and the driven roll 89, and the downstream portion of the maximum-sized medium P in the transport direction is sandwiched between the drive roll 84 and the driven roll 87. Therefore, the transport member 81 (drive roll 84 and driven roll 87) pulls the maximum-sized medium P together with the transport member 83 (drive roll 86 and driven roll 89).

[0166] The maximum size medium P is an example of a "medium whose length in the transport direction is equal to or greater than a predetermined length," and is at least the medium P whose length in the transport direction is the maximum. The minimum size medium P is an example of a "medium whose length in the transport direction is less than a predetermined length," and is at least the medium P whose length in the transport direction is the minimum.

[0167] Although the control device 160 is disposed in the image forming apparatus 10, this is not limitative. For example, the control device 160 may be disposed in the detection device 30 or another device disposed outside the image forming apparatus 10, and the location of the control device 160 is not limited.

[0168] (Front and rear end detection unit 90) The front and rear end detection unit 90 has a function of detecting the front and rear ends of the medium P when the transport is stopped and the medium P is pulled in the pulling direction. The front and rear end detection unit 90 is an example of a detection unit.

[0169] As shown in FIGS. 5 and 6, the front and rear end detection unit 90 includes sensors 91, 92, 93, and 94 (hereinafter referred to as 91 to 94), a sensor board 95, wiring 96 (see FIG. 6), and a reflector 97 (see FIG. 5).

[0170] 5 and 6, a plurality of sensors 93 and 94 are provided. Specifically, a pair (i.e., two) of sensors 93 and 94 are provided, as indicated by the symbols (A) and (B) in the drawings.

[0171] Sensor 93 is a detection unit that detects the leading edge of medium P. Sensor 94 is a detection unit that detects the trailing edge of medium P. Sensors 93 and 94 are non-contact sensors that detect the edges of medium P without coming into contact with medium P. More specifically, sensors 93 and 94 are optical sensors that use light irradiated toward medium P. Even more specifically, sensors 93 and 94 have multiple detection elements (specifically, light-emitting elements and light-receiving elements) arranged along the transport direction and are configured as line sensors that are elongated in the transport direction. Even more specifically, sensors 93 and 94 are configured as contact image sensors (CIS), as an example. Note that line sensors other than contact image sensors may be used as sensors 93 and 94.

[0172] In sensors 93 and 94, a detection area is formed by multiple detection elements arranged along the transport direction. The length of the detection area in the transport direction is the same as or shorter than the length of sensors 93 and 94 in the transport direction. Sensors 93 and 94 detect the position of the edge of medium P at the boundary between detection and non-detection of each detection element in the detection area, and position information indicated by the coordinates (specifically, the number of pixels from the downstream end of the detection area in the transport direction) is sent to, for example, control device 160.

[0173] The sensor 93 is disposed in a downstream portion of the detection device 30 in the transport direction (specifically, the left portion). The sensor 93 is disposed in a position facing the downstream end of the tensioned medium P in the transport direction. Specifically, the sensor 93 is disposed so that its longitudinal direction intersects with the downstream end of the tensioned medium P in the transport direction when viewed in a direction perpendicular to the image forming surface of the medium P, and detects this downstream end. More specifically, the sensor 93 is disposed so that its detection area intersects with the downstream end of the tensioned medium P in the transport direction when the tensioned medium P is stopped at a predetermined position when viewed in a direction perpendicular to the image forming surface of the medium P. In other words, the sensor 93 is disposed so that the downstream end of the tensioned medium P in the transport direction when the tensioned medium P is stopped at a predetermined position is located between one end and the other end of the longitudinal direction of the detection area of ​​the sensor 93.

[0174] The sensor 94 is disposed in an upstream portion of the detection device 30 in the transport direction (specifically, the right side portion). This sensor 94 is disposed in a position facing the upstream end of the tensioned medium P in the transport direction. Specifically, the sensor 94 is disposed so that its longitudinal direction intersects with the upstream end of the tensioned medium P in the transport direction when viewed in a direction perpendicular to the image forming surface of the medium P, and detects this upstream end. Even more specifically, the sensor 94 is disposed so that its detection area intersects with the upstream end of the tensioned medium P in the transport direction when the tensioned medium P is stopped at a predetermined position when viewed in a direction perpendicular to the image forming surface of the medium P. In other words, the sensor 94 is disposed so that the upstream end of the tensioned medium P in the transport direction when the tensioned medium P is stopped at a predetermined position is located between one end and the other end of the longitudinal direction of the detection area of ​​the sensor 94.

[0175] Specifically, sensors 93(A) and 94(A) are arranged side by side in the left-right direction in the front part of the detection device 30. On the other hand, sensors 93(B) and 94(B) are arranged side by side in the left-right direction in the rear part of the detection device 30.

[0176] In the front and rear end detection unit 90, a plurality of sensor substrates 95, wirings 96, and reflectors 97 are provided. Specifically, the number of sensor substrates 95, wirings 96, and reflectors 97 provided is the same as the number of sensors 93, 94. In the front and rear end detection unit 90, four wirings 96 and four reflectors 97 are provided. Furthermore, four sensor substrates 95 are provided, as indicated by the symbols (B), (C), (F), and (G) in the figure.

[0177] Each of the four sensor substrates 95 is a drive substrate that drives each of the four sensors 93, 94. Each of the four sensor substrates 95 is disposed adjacent to each of the four sensors 93, 94. Specifically, each of the sensors 93, 94 is driven by the sensor substrate 95 disposed closest to it among the four sensor substrates 95. That is, each of the sensors 93(A), 93(B), 94(A), and 94(B) is driven by each of the sensor substrates 95(B), 95(C), 95(F), and 95(G).

[0178] Each of the four wirings 96 is a connection line that electrically connects each of the four sensor substrates 95 with each of the four sensors 93, 94. The four wirings 96 are not bundled together and are spaced apart from one another. In other words, the four wirings 96 are not arranged such that one wiring 96 runs alongside the other wirings 96. The four wirings 96 are also arranged so that they do not cross each other. Each of the four reflecting plates 97 is provided on the conveyance path surface 41A of the plate body 41 of the detection device main body 40, facing each of the four sensors 93, 94. Considering the use of white paper as the medium P, the reflecting plate 97 is colored black, for example, which has a relatively large difference in reflectance from white.

[0179] (Side edge detection unit 98) The side edge detection unit 98 has the function of detecting the side edges of the medium P when the front and rear edge detection unit 90 detects the front and rear edges. In other words, the side edge detection unit 98 detects the side edges of the tensioned medium P. As shown in Figures 5 and 6, the side edge detection unit 98 includes sensors 91 and 92, a sensor board 95, wiring 96 (see Figure 6), and a reflector 97 (see Figure 5).

[0180] 5 and 6, a plurality of sensors 91 and 92 are provided. Specifically, a pair (i.e., two) of sensors 91 and 92 are provided, as indicated by the symbols (A) and (B) in the drawings.

[0181] Sensor 91 is a detection unit that detects one side edge of medium P (specifically, the side edge on the front side of the device). Sensor 92 is a detection unit that detects the other side edge of medium P (specifically, the side edge on the rear side of the device). Sensors 91 and 92 are non-contact sensors that detect the edges of medium P without coming into contact with medium P. More specifically, sensors 91 and 92 are optical sensors that use light irradiated toward medium P. Even more specifically, sensors 91 and 92 are configured as line sensors that have multiple detection elements (specifically, light-emitting elements and light-receiving elements) arranged along the width direction and are elongated in the width direction. Even more specifically, sensors 91 and 92 are configured as contact image sensors (CIS), as an example. Note that line sensors other than contact image sensors may be used as sensors 91 and 92.

[0182] In sensors 91 and 92, a detection area is formed by multiple detection elements arranged along the width direction. The width length of the detection area is the same as or smaller than the width length of sensors 91 and 92. Sensors 91 and 92 detect the position of the edge of medium P at the boundary between detection and non-detection of each detection element in the detection area, and position information indicated by the coordinates (specifically, the number of pixels from the rear end of the detection area) is sent to, for example, control device 160.

[0183] The sensor 91 is disposed in a front portion of the detection device 30. The sensor 91 is disposed in a position facing one side edge (i.e., one end in the width direction) of the tensioned medium P. Specifically, the sensor 91 is disposed so as to intersect with one side edge of the tensioned medium P in the longitudinal direction when viewed in a direction perpendicular to the image forming surface of the medium P, and detects this one side edge. More specifically, the sensor 91 is disposed so that, when viewed in a direction perpendicular to the image forming surface of the medium P, its detection area intersects with one side edge of the tensioned medium P stopped at a predetermined position in the longitudinal direction. In other words, the sensor 91 is disposed so that one side edge of the tensioned medium P stopped at a predetermined position is located between one end and the other end of the longitudinal direction of the detection area of ​​the sensor 91.

[0184] The sensor 92 is disposed in the rear portion of the detection device 30. The sensor 92 is disposed in a position facing the other side edge (i.e., the other end in the width direction) of the tensioned medium P. Specifically, the sensor 92 is disposed so that its longitudinal direction intersects with the other side edge of the tensioned medium P when viewed in a direction perpendicular to the image forming surface of the medium P, and detects the other side edge. More specifically, the sensor 92 is disposed so that its detection area intersects with the other side edge of the tensioned medium P stopped at a predetermined position when viewed in a direction perpendicular to the image forming surface of the medium P. In other words, the sensor 92 is disposed so that the other side edge of the tensioned medium P stopped at a predetermined position is located between one end and the other end of the longitudinal direction of the detection area of ​​the sensor 92.

[0185] Specifically, the sensor 91(A) and the sensor 92(A) are arranged side by side along the front-rear direction in a downstream portion of the detection device 30 in the conveying direction (specifically, the first unit 31). On the other hand, the sensor 91(B) and the sensor 92(B) are arranged side by side along the front-rear direction in an upstream portion of the detection device 30 in the conveying direction (specifically, the second unit 32).

[0186] Furthermore, in this embodiment, sensors 91 and 92 are located between sensors 93 and 94 in a side view. That is, sensors 91 and 92 are disposed upstream in the transport direction relative to sensor 93 and downstream in the transport direction relative to sensor 94. Note that a side view refers to a view from one side to the other in the width direction of medium P.

[0187] In the side edge detection unit 98, a plurality of sensor substrates 95, wirings 96, and reflectors 97 are provided. Specifically, the same number of sensor substrates 95, wirings 96, and reflectors 97 are provided as the sensors 91, 92. In the side edge detection unit 98, four of each of the wirings 96 and reflectors 97 are provided. Furthermore, four of the sensor substrates 95 are provided, as indicated by the symbols (A), (D), (E), and (H) in the figure.

[0188] Each of the four sensor substrates 95 is a drive substrate that drives each of the four sensors 91, 92. Each of the four sensor substrates 95 is disposed adjacent to each of the four sensors 91, 92. Specifically, each of the sensors 91, 92 is driven by the sensor substrate 95 disposed closest to it among the four sensor substrates 95. That is, each of the sensors 91(A), 92(A), 91(B), and 92(B) is driven by each of the sensor substrates 95(A), 95(D), 95(E), and 95(H).

[0189] Each of the four wirings 96 is a connection line that electrically connects each of the four sensor substrates 95 with each of the four sensors 91, 92. The four wirings 96 are not bundled together and are spaced apart from one another. In other words, the four wirings 96 are not arranged such that one wiring 96 runs alongside the other wirings 96. The four wirings 96 are also arranged so that they do not cross each other. Each of the four reflecting plates 97 is provided on the transport path surface 41A of the plate body 41 of the detection device main body 40, facing each of the four sensors 91, 92. Considering the use of white paper as the medium P, the reflecting plate 97 is colored black, for example, which has a relatively large difference in reflectance from white.

[0190] In this embodiment, the sensor boards 95(A), 95(B), 95(C), and 95(D) are attached to the mounting plate 59A of the board support part 59 so as to be arranged in this order toward the rear side. The sensor boards 95(E), 95(F), 95(G), and 95(H) are attached to the mounting plate 69A of the board support part 69 so as to be arranged in this order toward the rear side.

[0191] In this embodiment, sensors 91(A), 92(A), 93(A)(B) and sensor substrates 95(A), 95(B), 95(C), 95(D) are provided in the first unit 31. Wiring 96 is provided in the first unit 31 to electrically connect each of the sensors 91(A), 92(A), 93(A)(B) to each of the sensor substrates 95(A), 95(B), 95(C), 95(D).

[0192] In this embodiment, sensors 91(B), 92(B), 94(A)(B) and sensor substrates 95(E), 95(F), 95(G), and 95(H) are provided in the second unit 32. Wiring 96 electrically connecting each of sensors 91(B), 92(B), and 94(A)(B) to each of sensor substrates 95(E), 95(F), 95(G), and 95(H) is provided in the second unit 32. As described above, because sensors 91-94 are provided in the first unit 31 and second unit 32, they detect the edge of medium P from above the tensioned medium P. Therefore, adhesion of foreign matter such as paper dust to sensors 91-94 is suppressed compared to when sensors 91-94 detect the edge of medium P from below the tensioned medium P.

[0193] (Pressing member 110) 12 and 13 is a member that presses down the end of the tensioned medium P. Pressing down the end of the medium P means restricting the movement of the end of the medium P from above and below.

[0194] As shown in Figures 12 and 13, a plurality of pressing members 110 are provided. Specifically, in this embodiment, four pressing members 110 are provided, as indicated by the reference characters (A), (B), (C), and (D) in Figure 12. The pressing members 110 are made of a plate-shaped elastic member such as a resin film.

[0195] As shown in Fig. 13, the presser members 110(A) and 110(B) are disposed between the conveying members 81 and 82 in a side view. Also, as shown in Fig. 12, the presser members 110(A) and 110(B) are disposed with the sensor 93(A) sandwiched between them in the front-to-rear direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0196] 13, the presser members 110(C) and 110(D) are disposed downstream in the conveying direction relative to the conveying member 81 in a side view. Also, as shown in FIG. 12, the presser members 110(C) and 110(D) are disposed with the sensor 93(A) sandwiched between them in the front-to-rear direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0197] The upstream ends (i.e., right ends) of the pressing members 110(A), 110(B), 110(C), and 110(D) in the conveying direction are attached to the conveying path surface 41A of the detection device main body 40, and the downstream portions (i.e., left portions) in the conveying direction are pressed against the conveying path surface 51A of the first unit 31 by their own elastic force. As a result, the pressing members 110(A), 110(B), 110(C), and 110(D) press the medium P conveyed between them and the conveying path surface 51A against the conveying path surface 51A, thereby pressing the ends (specifically, the downstream ends) of the medium P in a tensioned state.

[0198] Although not shown in Figures 12 and 13, in this embodiment, similar to the configuration described above, a pressure member 110 is arranged to sandwich the sensor 93 (B) in the front-to-back direction when viewed in a direction perpendicular to the image forming surface of the medium P.

[0199] As described above, in this embodiment, the presser members 110 are disposed so as to sandwich the sensor 93 in the front-rear direction as appropriate when viewed in a direction perpendicular to the image forming surface of the medium P.

[0200] (Pressing member 120) 6 is an example of a support unit, and supports the medium P whose side edge is detected by the side edge detection unit 98. Specifically, the presser member 120 presses down the side edge of the medium P in a tensioned state. Note that pressing down the side edge of the medium P means restricting movement of the side edge of the medium P from above and below.

[0201] As shown in Fig. 6, a plurality of pressing members 120 are provided. Specifically, in this embodiment, four pressing members 120 are provided, as indicated by the reference characters (A), (B), (C), and (D) in Fig. 6. The pressing members 120 are made of a plate-shaped elastic member such as a resin film.

[0202] The pressing members 120(A), 120(B), 120(C), and 120(D) are arranged downstream of the conveying member 83 in the conveying direction, and upstream of the conveying member 82 in the conveying direction.

[0203] The pressing member 120(A) is disposed along the sensor 92(A) on the upstream side of the sensor 92(A) in the conveying direction. The length of the pressing member 120(A) in the front-rear direction is approximately the same as the length of the sensor 92(A) in the front-rear direction.

[0204] The pressing member 120(B) is disposed along the sensor 92(B) on the upstream side in the conveying direction relative to the sensor 92(B). The length of the pressing member 120(B) in the front-to-rear direction is approximately the same as the length of the sensor 92(B) in the front-to-rear direction. The pressing members 120(A) and 120(B) are disposed behind the sensors 93(B) and 94(B).

[0205] The pressing member 120(C) is disposed along the sensor 91(A) on the upstream side of the sensor 91(A) in the conveying direction. The length of the pressing member 120(C) in the front-rear direction is approximately the same as the length of the sensor 91(A) in the front-rear direction.

[0206] Pressing member 120(D) is disposed along sensor 91(B) on the upstream side in the conveying direction relative to sensor 91(B). The length of pressing member 120(D) in the front-to-rear direction is approximately the same as the length of sensor 91(B) in the front-to-rear direction. Pressing members 120(C) and 120(D) are disposed forward of sensors 93(A) and 94(A).

[0207] The upstream ends (i.e., right ends) of the presser members 120(A), 120(B), 120(C), and 120(D) in the conveying direction are attached to the conveying path surface 41A of the detection device main body 40, and the downstream portions (i.e., left portions) in the conveying direction are pressed against the conveying path surface 51A of the first unit 31 by their own elastic force. As a result, the presser members 120(A), 120(B), 120(C), and 120(D) press the medium P conveyed between themselves and the conveying path surface 51A against the conveying path surface 51A, thereby pressing the side edges of the medium P in a tensioned state. This supports the side edges of the medium P.

[0208] Then, sensors 91(A), 91(B), 92(A), and 92(B) detect the side edges of medium P, the side edges of which are supported by pressing members 120(A), 120(B), 120(C), and 120(D).

[0209] In this embodiment, the pressing members 120(A), 120(B), 120(C), and 120(D) have a length in the front-to-rear direction, but each of the pressing members 120(A), 120(B), 120(C), and 120(D) may be composed of multiple members divided into multiple parts in the front-to-rear direction.

[0210] (Control function of the control device 160 for the detection device 30) Here, a control function of the control device 160 to control the operation of the detection device 30 will be described. Figures 14 and 15 illustrate components of the control device 160 that perform the control function of controlling the operation of the detection device 30. Specifically, as described above, the control device 160 has the processor 161, memory 162, and storage 163 (see Figure 14).

[0211] 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 15 is a block diagram showing the functional configuration of the processor 161.

[0212] As shown in FIG. 15, 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.

[0213] The acquisition unit 161A acquires detection information obtained by the front and rear end detection unit 90 and the side end detection unit 98 detecting the ends of the medium P. The detection information includes position information indicating the positions of the ends of the medium P. Specifically, the position information is position information indicating the position in the transport direction for the front and rear ends 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.

[0214] Specifically, the acquisition unit 161A, for example, detects the position of the edge of the medium P at the boundary between detection and non-detection of individual detection elements in the detection area using sensors 93 and 94, and acquires position information indicated by the coordinates (specifically, the number of pixels from the downstream end of the detection area in the conveying direction).

[0215] In addition, the acquisition unit 161A, for example, detects the position of the edge of the medium P at the boundary between detection and non-detection of each detection element in the detection area by the sensors 91 and 92, and acquires position information indicated by its coordinates (specifically, the number of pixels from the rear end of the detection area).

[0216] Based on the position information acquired by the acquisition unit 161A, the measurement unit 161B measures the transport direction length and width direction length of the medium P. Specifically, the measurement unit 161B measures the transport direction length of the medium P, for example, as follows.

[0217] For example, as shown in FIGS. 21 and 23, the measurement unit 161B determines the distance LB from the trailing edge of the medium P to the upstream edge (ie, the right edge) of the detection area of ​​the sensor 94 based on the position information.

[0218] Specifically, the distance LB is calculated using the following formula (1) based on the total number of pixels P1 (pixels / mm) of the detection elements of the sensor 94 and the number of pixels P2 (pixels) from the upstream end of the detection area of ​​the sensor 94 in the transport direction to the rear end of the medium P. Note that Figures 21 to 23 are conceptual diagrams, and each component (transport members 82, 83, sensors 91 to 94) is shown schematically.

[0219] Formula (1): LB=P2÷P1

[0220] Furthermore, the measurement unit 161B calculates the distance LC from the leading edge of the medium P to the upstream edge (ie, the right edge) of the detection area of ​​the sensor 93 based on the position information, for example.

[0221] Specifically, the distance LC is calculated using the following formula (2) based on the total number of pixels P3 (pixels / mm) of the detection elements of the sensor 93 and the number of pixels P4 (pixels) from the upstream end of the detection area of ​​the sensor 93 in the transport direction to the front end of the medium P.

[0222] Formula (2): LC=P4÷P3

[0223] Here, the distance LA from the upstream end (i.e., the right end) of sensor 94 to the upstream end (i.e., the right end) of sensor 93 is known. Then, the measurement unit 161B calculates the transport direction length L1 of the medium P using the following equation (3).

[0224] Equation (3): L1 = LA + LC - LB

[0225] Furthermore, the measuring unit 161B measures the width direction length of the medium P, for example, as follows.

[0226] For example, as shown in FIG. 23, the measurement unit 161B determines the distance WB from one side edge of the medium P (i.e., the edge toward the rear of the device) to the rear edge of the detection area of ​​the sensor 92 (i.e., the edge toward the rear of the device) based on the position information.

[0227] Specifically, the distance WB is calculated using the following equation (4) based on the total number of pixels P5 (pixels / mm) of the detection elements of the sensor 92 and the number of pixels P6 (pixels) from the rear end of the detection area of ​​the sensor 92 to one side end of the medium P.

[0228] Formula (4): WB=P6÷P5

[0229] Furthermore, the measurement unit 161B, for example, calculates the distance WC from the other side edge of the medium P (i.e., the edge on the front side of the device) to the rear edge of the detection area of ​​the sensor 91 (i.e., the edge on the rear side of the device) based on the position information.

[0230] Specifically, the distance WB is calculated using the following equation (5) based on the total number of pixels P7 (pixels / mm) of the detection elements of the sensor 91 and the number of pixels P8 (pixels) from the rear end of the detection area of ​​the sensor 91 to the other side end of the medium P.

[0231] Formula (5): WC=P8÷P7

[0232] Here, the distance WA from the rear end of sensor 92 to the rear end of sensor 91 is known. Then, the measurement unit 161B calculates the width direction length W1 of the medium P using the following equation (6).

[0233] Formula (6): W1=WA+WC-WB

[0234] Then, the measuring unit 161B measures the size (dimensions) of the medium P from the measured length of the medium P in the transport direction and the length of the medium P in the width direction.

[0235] In this embodiment, the conveying direction length L1 of the medium P at one end and the other end in the width direction is measured from the detection results of sensors 93(B) and 94(B) arranged in the left-right direction in the rear part of the detection device 30 and the detection results of sensors 93(A) and 94(A) arranged in the left-right direction in the front part of the detection device 30.

[0236] Here, when paper is used as the medium P, the transport 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, but it is possible to measure the cutting error by measuring the transport direction length L1 between the one end portion and the other end portion of the medium P in the width direction. Note that, for example, any one of the average value, minimum value, and maximum value of the transport direction length L1 between the one end portion and the other end portion of the medium P in the width direction can be set as the transport direction length of the medium P.

[0237] In addition, in this embodiment, the widthwise length W1 of the medium P at the downstream and upstream portions in the transport direction is measured from the detection results of sensors 91(A) and 92(A) arranged along the front-to-back direction in the left portion of the detection device 30 and the detection results of sensors 91(B) and 92(B) arranged along the front-to-back direction in the right portion of the detection device 30.

[0238] Here, when paper is used as the medium P, the width direction length W1 may differ between the downstream and upstream portions of the medium P in the transport direction due to cutting errors, but it is possible to measure the cutting error by measuring the width direction length W1 of the downstream and upstream portions of the medium P in the transport direction. Note that, for example, the width direction length of the medium P can be determined as any one of the average value, minimum value, and maximum value of the width direction length W1 of the downstream and upstream portions of the medium P in the transport direction.

[0239] Furthermore, in this embodiment, for example, skew (i.e., tilt) of medium P may be detected from the deviation in detection position between sensors 91(A), 92(A), 93(A), and 94(A) and sensors 91(B), 92(B), 93(B), and 94(B). The amount of tilt of medium P may be corrected to determine the length of medium P in the transport direction and the length of medium P in the width direction.

[0240] The control unit 161C performs image adjustment of the image formed on the medium P whose edge has been detected, based on the size (dimensions) of the medium P measured by the measurement unit 161B. That is, after the detection device 30 detects the edge of the medium P, the control unit 161C performs image adjustment of the back-side image formed on the detected medium P, based on the size (dimensions) of the medium P measured by the measurement unit 161B. For example, when the size of the medium P measured by the measurement unit 161B is smaller than the size specified as the size of the medium P on which the image is to be formed, the control unit 161C controls the image forming unit 14 to reduce and form the back-side image.

[0241] Although the control device 160 is disposed in the image forming apparatus 10, this is not limitative. For example, the control device 160 may be disposed in the detection device 30 or another device disposed outside the image forming apparatus 10, and the location of the control device 160 is not limited.

[0242] (Arrangement of the detection device 30) As described above, the detection device 30 is disposed inside the image forming apparatus main body 11. Specifically, the detection device 30 is disposed above the medium storage unit 12 in the vertical direction. As described above, the detection device 30 is formed in a flat shape that extends in the front-to-rear and left-to-right directions (specifically, the horizontal direction), thereby saving space in the vertical direction.

[0243] Furthermore, the detection device 30 including the transport unit 80 is disposed at a position in the image forming apparatus 10 in which the detection device 30 is disposed, where transport of the medium P is stopped. More specifically, the detection device 30 including the transport unit 80 is disposed in the transport path 24 of the image forming apparatus 10, where the medium P is stopped to change the direction of the transported medium P. Specifically, the transport path 24 is the transport path where the medium P is stopped to turn the medium P over.

[0244] In the conveying path 24, the medium P is turned over by being switched back. The switchback is an operation of moving the medium P back and forth within the same path. In other words, the switchback is an operation of changing the direction of the medium P.

[0245] As described above, the conveying path 24 is a path along which the medium P is conveyed from the heating unit 19 to the image forming unit 14. Furthermore, the detection device 30 is disposed on the conveying path 24 upstream in the conveying direction of the supply position 25A where new medium P is supplied toward the image forming unit 14.

[0246] In this embodiment, as described above, the medium container 12, the image forming unit 14, and the heating unit 19 are arranged in the portion 18A of the housing 18. The detection device 30 is arranged in the portion 18B of the housing 18. In other words, the detection device 30 including the front and rear edge detection unit 90 and the heating unit 19 are provided in different portions 18A and 18B of the housing 18.

[0247] Furthermore, in this embodiment, as described above, the detection device 30 including the front and rear end detection unit 90 is provided downstream in the transport direction from the heating unit 19. Therefore, after the medium P is heated and before an image is formed on the medium P again, the front and rear end detection unit 90 detects the front and rear ends of the medium P, which is in a tensioned state and whose transport has been stopped.

[0248] In this embodiment, the detection device 30 including the front and rear end detection unit 90 is provided below the heating unit 19.

[0249] (Action according to this embodiment) As described above, in the detection device 30, the front and rear end detection unit 90 detects the front and rear ends of the medium P when the transport is stopped and the medium P is being pulled in the pulling direction.

[0250] Here, in a configuration (Comparative Example 1) in which the front and rear ends of the medium P being transported on the transport path 80B are detected by a detection unit having a sensor or the like, since the medium P is moving, the posture of the medium P is prone to change, and it may not be possible to accurately detect the front and rear ends of the medium P.

[0251] Furthermore, for example, in a configuration (Comparative Example 2) in which the transport of a medium P is stopped and the leading and trailing ends of the medium P are detected, if the medium P is bent, the leading and trailing ends may come close to each other, and the relative positions of the leading and trailing ends may not be accurately detected, as shown in Fig. 22. Specifically, as shown in Fig. 22, the distance LC is found as the distance LD.

[0252] In contrast, in this embodiment, as described above, the leading and trailing edge detector 90 detects the leading and trailing edges of the medium P when the transport is stopped and the medium is pulled in the pulling direction. This makes it possible to detect the leading and trailing edges of the medium P in a state where the medium P is less warped or wrinkled in the transport direction than in Comparative Examples 1 and 2. In other words, this embodiment reduces the likelihood of the leading and trailing edges of the medium P being detected when they are closer to each other in the transport direction than in Comparative Examples 1 and 2. Furthermore, this embodiment makes it possible to detect the leading and trailing edges of the medium P when the medium P is in a state where its orientation is closer to a plane than in Comparative Examples 1 and 2. As a result, the detection accuracy of the leading and trailing edges of the medium P is improved. Furthermore, the measurement accuracy of the length of the medium P in the transport direction is improved. Note that in FIG. 22 , the warped medium P is indicated by a solid line, and the pulled medium P is indicated by a two-dot chain line. 22 also shows a simplified view of the upper transport path surface of the medium P, which is made up of the transport path surfaces 51A, 61A, and 71A. The medium P in a bent state comes into contact with the upper transport path surfaces 51A, 61A, and 71A and the lower transport path surface 41A.

[0253] In this embodiment, in the transport path 80B, transport members 81, 82, and 83 that transport the medium P in the first transport direction and then stop the transport pull the medium P in the pulling direction.

[0254] Therefore, there is no need to provide a separate pulling means for pulling the medium P, and the number of parts is reduced compared to when the transport members 81, 82, and 83 only have the function of transporting the medium P.

[0255] In this embodiment, after the transport member 83 stops transporting the medium P, the transport members 81 and 82 stop transporting the medium P, and the transport members 81, 82, and 83 pull the medium P in the pulling direction.

[0256] Therefore, the medium P can be pulled while being stopped, and the total operation time for stopping and pulling is reduced compared to when the transport members 81, 82, and 83 simultaneously stop transporting the medium P and then at least one of the transport members 81, 82, and 83 operates to pull the medium.

[0257] In this embodiment, the downstream transport section 80Y has a transport member 81 and a transport member 82 arranged upstream of the transport member 81 in the transport direction.

[0258] Therefore, the degree of freedom in the position where the medium P is pulled is higher than when the downstream transport section 80Y has only a single transport member.

[0259] In this embodiment, the transport member 82 pulls the medium P of the smallest size together with the transport member 83, and the transport member 81 pulls the medium P of the largest size together with the transport member 83.

[0260] Therefore, even for the maximum size medium P, bending at the front end portion of the maximum size medium P is suppressed compared to when the medium P is pulled by the transport members 82 and 83.

[0261] In this embodiment, the conveying members 81 and 82 are rotated by a common drive source 777. Therefore, the number of parts is reduced compared to when the conveying members 81 and 82 are rolls rotated by separate drive sources.

[0262] In this embodiment, the pair of conveying parts with a short distance (specifically, conveying member 81 and conveying member 82) share a common drive source, and the pair of conveying parts with a long distance (specifically, conveying member 82 and conveying member 83) have separate drive sources, thereby reducing the number of parts while maintaining the pulling effect.

[0263] In this embodiment, the transport member 83 stops transporting the medium P so that the amount by which the rear end of the medium P protrudes from the transport member 83 toward the upstream side in the transport direction becomes approximately the same regardless of the length in the transport direction of the medium P. Furthermore, the transport members 81, 82, and 83 re-transport the medium P from the end side where the amount of protrusion has become approximately the same (i.e., the upstream end side in the transport direction (specifically, the right end side)).

[0264] Here, in a configuration in which the amount by which the rear end of medium P protrudes from conveying member 83 toward the upstream side in the conveying direction varies depending on the medium P, and medium P is re-conveyed from the side where it protrudes (hereinafter referred to as configuration A), the amount of protrusion changes, and therefore the time it takes for the medium to reach a conveying section, such as a conveying roll, located downstream in the conveying direction from conveying member 83 when re-conveyed varies, and in order to accommodate this, conveyance control of the conveying section may become complicated. In contrast, in this embodiment, conveyance of medium P is stopped so that the amount of protrusion from conveying member 83 toward the upstream side in the conveying direction is approximately the same regardless of the length of medium P in the conveying direction, and therefore conveyance control when re-conveying medium P is simplified compared to configuration A.

[0265] In this embodiment, a presser member 120 supports the medium P whose side edge is detected by the side edge detector 98. Here, in a configuration (hereinafter referred to as configuration B) that does not include a presser member 120 that supports the side edge when detecting the side edge of the medium P, the posture of the side edge of the medium P is likely to fluctuate. In contrast, in this embodiment, the presser member 120 supports the medium P whose side edge is detected by the side edge detector 98, so fluctuations in the posture of the side edge of the medium P are suppressed compared to configuration B, and it is possible to detect the side edge of the medium P in a state where sagging and wrinkles in the width direction of the medium P are reduced. As a result, the detection accuracy of the side edge of the medium is improved.

[0266] Each of the presser members 120(A), 120(B), 120(C), and 120(D) is disposed along each of the sensors 92(A), 92(B), 91(A), and 91(B) on the upstream side in the conveying direction of each of the sensors 92(A), 92(B), 91(A), and 91(B). Therefore, each of the presser members 120(A), 120(B), 120(C), and 120(D) detects the medium P in a supported state where the flexing of the medium P is eliminated, compared to when each of the presser members 120(A), 120(B), 120(C), and 120(D) is disposed downstream in the conveying direction of each of the sensors 92(A), 92(B), 91(A), and 91(B), thereby improving the detection accuracy of the side edges of the medium P.

[0267] In this embodiment, the front and rear end detection unit 90 detects the front and rear ends of the medium P in a tensioned state after the medium P has been heated and before an image is formed on the medium P again.

[0268] Therefore, even for media that are re-transported to the image forming unit 14 after heating, the detection accuracy of the leading and trailing ends of the media P is improved compared to when detecting the leading and trailing ends of the media P while it is being transported in the transport path.

[0269] In this embodiment, the detection device 30 including the front and rear end detection unit 90 and the heating unit 19 are provided in different parts 18A and 18B of the housing 18. Therefore, the influence of heat that the front and rear end detection unit 90 receives from the heating unit 19 is reduced compared to when the front and rear end detection unit 90 and the heating unit 19 are provided in the same part of the housing 18.

[0270] In this embodiment, the detection device 30 including the front and rear end detection units 90 is provided below the heating unit 19. Therefore, the front and rear end detection units 90 are less susceptible to the heat from the heating unit 19 than when the front and rear end detection units 90 are provided above the heating unit 19.

[0271] (Modification to the configuration for pulling the medium P) In the present embodiment, in the transport path 80B, the transport members 81, 82, and 83 that transport the medium P in the first transport direction and stop the transport pull the medium P in the pulling direction, but this is not limited to this. For example, the transport members 81, 82, and 83 may transport and stop the transport of the medium P, and a separately provided pulling means may pull the medium P. Examples of the pulling means include transport members such as transport rolls and transport belts, and a means that pulls the medium P using suction force.

[0272] Furthermore, in this embodiment, after the transport member 83 stops transporting the medium P, the transport members 81 and 82 stop transporting the medium P, and the transport members 81, 82, and 83 pull the medium P in the pulling direction, but this is not limited to this. For example, the transport members 81, 82, and 83 may simultaneously stop transporting the medium P, and then at least one of the transport members 81, 82, and 83 may operate to pull the medium. Note that when the transport members 81 and 82 operate, the drive rolls 84 and 85 rotate forward, and when the transport member 83 operates, the drive roll 86 rotates reversely.

[0273] (Modifications of the upstream transport section 80X and the downstream transport section 80Y) In the present embodiment, the downstream transport unit 80Y includes the transport member 81 and the transport member 82 disposed upstream of the transport member 81 in the transport direction, but is not limited to this. For example, the downstream transport unit 80Y may be configured to include only a transport unit such as a single transport member. Specifically, the downstream transport unit 80Y may be configured to include only the transport member 82, for example. In this configuration, media P of all sizes, including the minimum and maximum sizes, are pulled by the transport members 82 and 83.

[0274] In this way, in this embodiment, the minimum size medium P and the maximum size medium P may be pulled by the same transport unit such as the same transport member. Furthermore, the downstream transport unit 80Y may be configured to have three or more transport units such as the same transport members.

[0275] Furthermore, in this embodiment, the upstream transport unit 80X has only the transport member 83, but it may have transport units such as multiple transport members. In this case, for example, it is possible for the downstream transport unit 80Y to have a single transport unit, and the upstream transport unit 80X to have a configuration (hereinafter referred to as a first configuration) including a first transport unit and a second transport unit arranged upstream in the transport direction from the first transport unit. In the first configuration, the first transport unit may pull, together with the downstream transport unit 80, a medium P whose length in the transport direction is less than a predetermined length, and the second transport unit may pull, together with the downstream transport unit 80, a medium P whose length in the transport direction is equal to or greater than the predetermined length.

[0276] Furthermore, in the first configuration, for example, instead of the rear end sensor 99, a front end sensor is provided as a detection unit that detects the front end of the medium P, and the medium P can be stopped based on the timing when the front end sensor detects the front end of the medium P. Furthermore, by stopping the medium P based on the timing when the front end sensor detects the front end of the medium P, the downstream transport unit 80Y can stop transport of the medium P so that the amount by which the front end of the medium P protrudes downstream in the transport direction from the downstream transport unit 80Y is approximately the same regardless of the length of the medium P in the transport direction.

[0277] Furthermore, in a modified example in which the detection device 30 is positioned downstream in the conveying direction relative to the conveying path 80A and upstream in the conveying direction relative to the transfer position TA, the conveying members 81, 82, and 83 can re-convey the medium P from the end side (i.e., the downstream side in the conveying direction) that has approximately the same protrusion amount.

[0278] (Change in pulling force by conveying members 81, 82, 83) The tensile force of the conveying members 81, 82, and 83 may be changed depending on the characteristics of the medium P. Specifically, the tensile force of the conveying members 81, 82, and 83 may be changed depending on the type of the medium P. The types of the medium P include types related to thickness, such as thin paper, plain paper, and thick paper, and types related to whether or not the medium is coated, such as coated paper and uncoated paper. The characteristics of the medium P include the type, stiffness, thickness, basis weight, size, weight, temperature, and the like of the medium P.

[0279] Specifically, the conveying members 81, 82, and 83 are configured to apply, for example, a first tensile force to a first type of medium P, and a second tensile force stronger than the first tensile force to a second type of medium having higher rigidity than the first type of medium P.

[0280] The tensile force is changed by changing the second elapsed time (i.e., the time difference) from when the conveying member 83 stops rotating until the conveying members 81 and 82 stop rotating. That is, by lengthening the second elapsed time, the tensile force is increased.

[0281] In this configuration in which the tensile force is changed depending on the type of medium P, multiple types of medium P are transported along transport path 80B. Along transport path 80B, detection device 30 (specifically, front and rear end detection unit 90) detects the front and rear ends of multiple types of medium P when transport is stopped and the medium P is in a tensioned state. This detection device 30 changes the tensile force depending on the type of medium P. Then, image forming unit 14 forms images on multiple types of medium P based on the detection results of detection device 30.

[0282] In a configuration in which the tensile force of the conveying members 81, 82, and 83 is changed depending on the characteristics of the medium P, wrinkles in the medium P are suppressed compared to when the tensile force of the conveying members 81, 82, and 83 is constant.

[0283] Furthermore, in this example, the detection device 30 changes the tensile force depending on the type of medium P, so that appropriate image formation can be performed for the type of medium P, compared to a system in which multiple types of media P are pulled with a constant tensile force and image formation is performed based on the results of detecting the front and rear ends of multiple types of media P.

[0284] (Modification of image formed on medium P) In the present embodiment, the front image as the first image is formed on one side of the medium P, and the back image as the second image is formed on the other side of the medium P, but this is not limiting. The second image may be formed on the side of the medium P on which the first image is formed.

[0285] Furthermore, in this embodiment, the front image as the first image and the back image as the second image are formed by the same image forming unit 14, but they may be formed by different image forming units.

[0286] The first image may be, for example, an image formed by other means (for example, an image forming unit provided in the image forming device 10 separately from the image forming unit 14, or an image forming device separate from the image forming device 10) instead of or in addition to the image formed by the image forming unit 14. The first image may be any image formed on the medium P before the edge of the medium P is detected.

[0287] (Modification of the conveying section 80) In the present embodiment, the connectors 743, 753, 763, the drive sources 777, 778, and the control device 160, which are connected to the connectors 843, 853, 863 of the drive rolls 84, 85, 86, are provided in the image forming apparatus main body 11. However, the present invention is not limited to this. The connectors 743, 753, 763, the drive sources 777, 778, and the control device 160 may be provided in the detection device 30.

[0288] In the present embodiment, the transporting members 81 and 82 are configured to be rotated by a common drive source 777, but this is not limiting. For example, the transporting members 81 and 82 may be configured to be rotated by separate drive sources.

[0289] Furthermore, in the present embodiment, the transport member 83 stops transport of the medium P so that the amount by which the rear end of the medium P protrudes from the transport member 83 toward the upstream side in the transport direction is substantially the same regardless of the length of the medium P in the transport direction, but this is not limited to this. For example, the amount by which the rear end of the medium P protrudes from the transport member 83 toward the upstream side in the transport direction may be configured to vary depending on the medium P.

[0290] In this embodiment, drive rolls 84, 85, and 86 are used as the rotating members, but this is not limited thereto. For example, rolls, rollers, belts, wheels, etc. may be used alone or in combination as the rotating members. When a belt is used as the rotating member, the belt is wound around multiple rolls and rotates by receiving driving force from the rolls. Furthermore, the rotating members may be members that are not driven to rotate, as long as they rotate.

[0291] In this embodiment, the driven members are the driven rolls 87, 88, and 89, but are not limited to this. The driven members may be, for example, rollers, belts, wheels, etc., as long as they are members that are driven by the rotating member.

[0292] In addition, in the present embodiment, the drive rolls 84, 85, and 86 as rotating members are arranged in the detection device main body 40, and the driven rolls 87, 88, and 89 as driven members are arranged in the first unit 31 and the second unit 32, which are units arranged above the detection device main body 40. However, this is not limited to this. For example, a configuration may be possible in which driven members such as the driven rolls 87, 88, and 89 are arranged in the detection device main body 40, and rotating members such as the drive rolls 84, 85, and 86 are arranged in the first unit 31 and the second unit 32.

[0293] Furthermore, in the present embodiment, the driven rolls 87, 88, 89 and roll portions 842, 852, 862 are arranged to sandwich the sensors 93, 94 in the front-to-rear direction (i.e., the width direction of the medium P) as appropriate when viewed in a direction perpendicular to the image forming surface of the medium P, but this is not limited to this. For example, the driven rolls 87, 88, 89 and roll portions 842, 852, 862 may be arranged to sandwich the sensors 93, 94 in the transport direction as appropriate when viewed in a direction perpendicular to the image forming surface of the medium P. Furthermore, the driven rolls 87, 88, 89 and roll portions 842, 852, 862 may be arranged in positions that do not sandwich the sensors 93, 94.

[0294] In this embodiment, the first conveying direction is the leftward direction, and the second conveying direction is the rightward direction, but this is not limiting. The first conveying direction and the second conveying direction may be, for example, forward, backward, upward, downward, or any other direction.

[0295] Although the second transport direction is the opposite direction to the first transport direction in the above embodiment, it is not limited to this. The second transport direction may be, for example, a direction intersecting the first transport direction, or may be any direction different from the first transport direction. When the second transport direction is intersecting the first transport direction, the detection device 30 may be configured to invert the medium P by a Möbius turn method. The Möbius turn method is a method of inverting the medium P by transporting the medium P by turning it back and forth multiple times so that the orientation of the medium P changes by 90 degrees each time, as viewed in a direction perpendicular to the image formation surface of the medium P. Furthermore, the second transport direction may be, for example, the same direction as the first transport direction.

[0296] (Modification of the pressing member 110) In the present embodiment, the presser member 110 is disposed so as to sandwich the sensor 93 in the front-to-rear direction as appropriate when viewed in a direction perpendicular to the image forming surface of the medium P, but this is not limited to this. The presser member 110 may be disposed so as to sandwich the sensor 93 in the conveyance direction as appropriate when viewed in a direction perpendicular to the image forming surface of the medium P. The presser member 110 may also be disposed in a position that does not sandwich the sensor 93. For example, the presser member 110 may be disposed in a position facing the sensor 93, or in a position shifted from the facing position, as long as the presser member 110 does not affect detection by the sensor 93.

[0297] Furthermore, in this embodiment, the presser member 110 presses down the downstream end of the medium P detected by the sensor 93, but instead of or in addition to this, it may be configured to press down one side end, the other side end, and the downstream end of the medium P detected by each of the sensors 91, 92, and 94. Note that the presser member 110 only needs to press down the end of the medium P that is the detection target, so in a configuration where there is an end that is not the detection target, the presser member 110 does not need to be arranged for that end.

[0298] Furthermore, the pressing member 110 is not limited to a plate-shaped elastic member such as a resin film. The pressing member 110 may be any member that supports the detection device main body 40 at a position above the transport path surface 41A, and may be a protruding part such as a rib, a driving, driven, or non-rotating roll, a belt, a roller, a wheel, or the like. Furthermore, the member that supports the medium P may be a member that supports the medium P by blowing or sucking a gas such as air.

[0299] (Modification of the pressing member 120) In the present embodiment, each of the presser members 120(A), 120(B), 120(C), and 120(D) is disposed along each of the sensors 92(A), 92(B), 91(A), and 91(B) on the upstream side of each of the sensors 92(A), 92(B), 91(A), and 91(B) in the conveying direction, but this is not limiting. For example, each of the presser members 120(A), 120(B), 120(C), and 120(D) may be disposed downstream of each of the sensors 92(A), 92(B), 91(A), and 91(B) in the conveying direction.

[0300] Furthermore, an example of the support unit is not limited to the presser member 120. An example of the support unit may be anything that supports the medium P whose side edge is detected by the side edge detection unit 98, such as a protruding part such as a rib, a driving, driven, or non-rotating roll, a belt, a roller, or a wheel. Another example of the support unit may be something that supports the medium P by blowing or sucking gas such as air.

[0301] Furthermore, this embodiment may be configured without the presser member 120 that supports the medium P whose side edge is detected by the side edge detector 98.

[0302] (Modification of the opening / closing unit 70) In this embodiment, the opening / closing unit 70 is disposed between the sensors 91(A), 92(A) and the sensors 91(A), 92(B) at a position where the sensors 91 to 94 are not present, but this is not limiting. For example, the opening / closing unit 70 may be disposed at a position where the sensors 93 and 94 are not present, and may be opened and closed together with the sensors 91 and 92. In this case, it is necessary to configure the opening / closing unit 70 so that the positioning accuracy of the opening / closing unit 70 does not affect the detection accuracy of the sensors 91 and 92.

[0303] Furthermore, the detection device 30 may not have the opening / closing unit 70, and may have a configuration in which the opening 77 that opens the transport path 80A (see FIG. 1) in the transport unit 80 cannot be opened or closed.

[0304] (Modifications of the front and rear edge detectors 90 and the side edge detectors 98) In this embodiment, the sensors 91 to 94 are reflective optical sensors, but are not limited to this. For example, the sensors 91 to 94 may be transmissive optical sensors. The sensors 91 to 94 may be detectors that detect the edge of the medium P by contact with the edge of the medium P, and various detectors may be used. An example of a detector that detects the edge of the medium P by contact with the edge of the medium P is a detector that uses a contact member (e.g., a guide member) that contacts the side edge of the medium P. The sensors 91 to 94 may be cameras that capture images of the medium P and detect the edge of the medium P. Even when the length of the medium P is measured from an image captured by a camera, the length is the distance between the edges of the medium P, and therefore the edge of the medium P can be said to be detected.

[0305] In this embodiment, each of the sensors 91 to 94 is arranged so as to intersect with the end of the medium P in a tensioned state in the longitudinal direction when viewed in a direction perpendicular to the image forming surface of the medium P, but this is not limited to this. For example, each of the sensors 91 to 94 may be arranged so as to intersect with the end of the medium P in the lateral direction. Furthermore, each of the sensors 91 to 94 may be a sensor that does not have a longitudinal direction (for example, a square sensor when viewed in a direction perpendicular to the image forming surface of the medium P).

[0306] In addition, in this embodiment, the front and rear edge detection unit 90 and the side edge detection unit 98 detect one edge of the medium P using multiple sensors, but this is not limited to this. For example, a configuration may be provided in which only one sensor is provided to detect one edge of the medium P.

[0307] In addition, in the present embodiment, the sensors 91 to 94 are provided in the first unit 31 and the second unit 32, but this is not limiting. For example, the sensors 91 and 93 may be provided in the detection device main body 40, and the sensors 92 and 94 may be provided in the first unit 31 and the second unit 32.

[0308] Furthermore, in this embodiment, the front and rear end detectors 90 and the side end detectors 98 are provided, but it is sufficient if at least the front and rear end detectors 90 are provided.

[0309] The front and rear end detection unit 90 may be configured to detect the front and rear ends of the tensioned medium P for the largest size medium P, which has the longest length in the transport direction, and not detect the front and rear ends of the tensioned medium P for the smallest size medium P, which has the smallest length in the transport direction. In this configuration, for example, the front and rear end detection unit 90 detects the front and rear ends of the tensioned medium P for media P of sizes other than the smallest size, including the largest size medium P, and does not detect the front and rear ends of the tensioned medium P for the smallest size medium P.

[0310] Furthermore, in this configuration, for example, the size of the medium P is measured upstream in the conveying direction relative to the detection device 30, and based on the measurement results, the front and rear end detection unit 90 determines whether or not to perform the detection operation of the front and rear ends of the medium P.

[0311] In this configuration, for the smallest size medium P, which has the smallest length in the conveying direction, the front and rear end detection unit 90 does not detect the front and rear ends of the medium P, so the number of times the front and rear end detection unit 90 detects the front and rear ends of the medium P is reduced compared to when the front and rear end detection unit 90 always detects the front and rear ends of the medium P regardless of the length of the medium P in the conveying direction.

[0312] (Modification of the arrangement of the detection device 30) In the present embodiment, the detection device 30 is disposed inside the image forming apparatus main body 11, but this is not limiting. The detection device 30 may be disposed outside the image forming apparatus main body 11. When the detection device 30 is disposed outside the image forming apparatus main body 11, the detection device 30 may be disposed directly outside the image forming apparatus main body 11, or may be disposed indirectly with another device or the like interposed between the detection device 30 and the image forming apparatus main body 11. Furthermore, the detection device 30 may be disposed in another device disposed in the image forming apparatus main body 11. The detection device 30 may operate in cooperation or in conjunction with the image forming apparatus main body 11 as necessary.

[0313] In the present embodiment, the detection device 30 including the front and rear end detection units 90 and the heating unit 19 are provided in different parts 18A and 18B of the housing 18, but this is not limiting. For example, the detection device 30 including the front and rear end detection units 90 and the heating unit 19 may be provided in the same part of the housing 18.

[0314] In the present embodiment, the detection device 30 including the front and rear end detection units 90 is provided below the heating unit 19, but this is not limiting. The detection device 30 including the front and rear end detection units 90 may be configured to be provided above the heating unit 19.

[0315] Furthermore, in the present embodiment, the detection device 30 is disposed on the upstream side of the transport path 24 in the transport direction relative to the supply position 25A where new medium P is supplied toward the image forming unit 14 (specifically, on the transport path 80A). However, this is not limited to this. For example, instead of or in addition to the detection device 30 disposed on the transport path 24 (specifically, on the transport path 80A), the detection device 30 may be disposed downstream of the transport path 80A in the transport direction and upstream of the supply position 25A in the transport direction. In this configuration, for example, the detection device 30 is disposed at a position where it is stopped to maintain a distance from the medium P supplied from the medium storage unit 12 to the supply position 25A. In the transport unit 80 in this configuration, for example, transport of the medium P on which an image has been formed on the front side in the first transport direction is stopped and the medium P is pulled. After the medium P is stopped, transport of the medium P is resumed in the second transport direction, which is the same direction as the first transport direction, toward the image forming unit 14 (specifically, the transfer position TA). In this configuration, the detection device 30 disposed on the transport path 80A may not be provided, and the transport path 24 may be configured as a transport path in which the medium P is not reversed. In this configuration, the second image is formed again on one side (front side) of the medium P on which the front side image as the first image is formed. In this way, the second image may be an image formed on the side on which the first image is formed.

[0316] Furthermore, for example, instead of or in addition to the detection device 30 arranged in the transport path 24 (specifically, the transport path 80A), the detection device 30 may be arranged downstream in the transport direction from the supply position 25A. In this configuration, for example, the detection device 30 is arranged at a position where the detection device 30 is stopped in order to adjust the timing of transport of the medium P to the image forming unit 14 (specifically, the transfer position TA). In the transport unit 80 in this configuration, for example, transport of the medium P on which an image has been formed on the front side in the first transport direction is stopped and the medium P is pulled, and after the medium P has stopped, transport of the medium P is resumed in the second transport direction, which is the same direction as the first transport direction, toward the image forming unit 14 (specifically, the transfer position TA).

[0317] (Configuration when using a delivery mechanism 250 having a suction unit 252) 24, a configuration may be used in which the medium P stored in the medium storage unit 12 is sent out by a sending mechanism 250 having a suction unit 252. As shown in FIGS. 24 and 25, the sending mechanism 250 has a suction unit 252 that sucks the medium P from the medium storage unit 12, and a sending roll 245 that sends out the medium P sucked by the suction unit 252. The sending roll 245 is an example of a sending unit.

[0318] In the delivery mechanism 250, as shown in Figures 25(A) and 25(B), a suction unit 252 disposed above the medium storage unit 12 adsorbs the medium P to its lower surface by suction, and as shown in Figure 25(C), the suction unit 252 moves toward the delivery roll 245, thereby transferring the medium P to the delivery roll 245. Then, the delivery roll 245 rotates to deliver the medium P. The medium P delivered by the delivery roll 245 is transported along a transport path 21A from the medium storage unit 12 to the image forming unit 14.

[0319] 24, in addition to or instead of the detection device 30 disposed in portion 18B of the housing 18, a detection device 30 is provided, for example, on the transport path 21A. In this configuration, the front and rear end detection units 90 of the detection device 30 detect the front and rear ends of the medium P in a tensioned state on the transport path 21A along which the medium P delivered by the delivery roll 245 is transported. Furthermore, the image forming unit 14 forms an image on the medium detected by the front and rear end detection units 90. Furthermore, the front and rear end detection units 90 detect the front and rear ends of the medium P when they pass through the delivery roll 245 and are positioned between the delivery roll 245 and the image forming unit 14.

[0320] Therefore, compared to when the leading and trailing edge detector 90 detects the leading and trailing edges of the medium P using the suction unit 252, the influence of suction from the suction unit 252 on the detection unit is reduced.

[0321] 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]

[0322] 10 Image forming device 14, 214 Image forming section 18 Case 19 Heating section 30 Detection device 80B, 21A transport route 80X Upstream transport section 80Y downstream transport section 81 conveying member (an example of a first conveying portion) 82 conveying member (an example of a second conveying section) 90 Front and rear end detection unit (example of detection unit) 98 Side edge detector 120 Pressing member (an example of a support part) 245 Delivery roll (an example of the delivery section) 252 Suction part 777 Power Source P medium

Claims

1. a transport path along which the medium is transported; a detection unit that detects the leading edge and the trailing edge of the medium when the medium is stopped and pulled in a pulling direction along the transport path; an upstream transport unit that transports the medium in the transport path in a transport direction and stops the transport; a downstream transport unit that is disposed downstream in a transport direction relative to the upstream transport unit and that transports the medium in the transport path in the transport direction and stops the transport; Equipped with The medium is a medium that may bend during transportation, The upstream transport unit and the downstream transport unit pull the medium in the pulling direction. Detection device.

2. The downstream conveying section The medium is transported by the upstream transport unit, and the transport is stopped after the upstream transport unit stops transporting, thereby pulling the medium in the pulling direction by the upstream transport unit. The detection device according to claim 1 .

3. The upstream conveying section or the downstream conveying section is A first conveying unit; a second conveying section disposed upstream of the first conveying section in a conveying direction; have 3. The detection device according to claim 1 or 2.

4. The second conveying section of the downstream conveying section is The medium having a length in a transport direction that is less than a predetermined length is pulled by the upstream transport unit, The first conveying section The medium having a length in the transport direction equal to or greater than a predetermined length is pulled by the upstream transport unit. The detection device according to claim 3 .

5. The first conveying section and the second conveying section are The rolls are rotated by a common drive source.

5. The detection device according to claim 3 or 4.

6. The upstream conveying section or the downstream conveying section is The tension force is changed depending on the characteristics of the medium. The detection device according to any one of claims 1 to 5.

7. The upstream conveying section or the downstream conveying section is stopped so that the amount by which the end of the medium protrudes from the upstream conveying section or the downstream conveying section is approximately the same regardless of the length of the medium in the conveying direction, The medium is re-transported from the end side where the protrusion amount is approximately the same. The detection device according to any one of claims 1 to 6.

8. The detection unit For a medium whose length in the transport direction is equal to or greater than a predetermined length, the leading edge and trailing edge of the medium are detected when transport is stopped and the medium is pulled in the pulling direction, and for a medium whose length in the transport direction is less than the predetermined length, the leading edge and trailing edge of the medium are not detected. The detection device according to any one of claims 1 to 6.

9. A side edge detection unit that detects the side edges of the medium when the detection unit detects the front edge and the rear edge; a support portion that supports the side edge of the medium detected by the side edge detection portion; The detection device according to any one of claims 1 to 8, comprising:

10. The support portion is disposed along the side edge detection portion on the upstream side of the side edge detection portion in the conveying direction. The detection device according to claim 9.

11. An image forming unit that forms an image on a medium; a heating section that heats the medium on which the image is formed; a conveying path along which the heated medium is conveyed; a detection unit that detects the leading edge and the trailing edge of the medium when the medium is stopped and pulled in a pulling direction along the transport path; an upstream transport unit that transports the medium in the transport path in a transport direction and stops the transport; a downstream transport unit that is disposed downstream in a transport direction relative to the upstream transport unit and that transports the medium in the transport path in the transport direction and stops the transport; Equipped with The medium is a medium that may bend during transportation, the upstream transport unit and the downstream transport unit pull the medium in the pulling direction; the image forming unit forms an image again on the heated medium, The detector detects the leading and trailing edges of the media after the media is heated and before the media is reimaged. Image forming device.

12. An image forming unit that forms an image on a medium; a heating section that heats the medium on which the image is formed; a conveying path along which the heated medium is conveyed; a detection unit that detects the leading edge and the trailing edge of the medium when the medium is stopped and pulled in a pulling direction along the transport path; an upstream transport unit that transports the medium in the transport path in a transport direction and stops the transport; a downstream transport unit that is disposed downstream in a transport direction relative to the upstream transport unit and that transports the medium in the transport path in the transport direction and stops the transport; Equipped with The medium is a medium that may bend during transportation, the upstream transport unit and the downstream transport unit pull the medium in the pulling direction; The detecting unit and the heating unit are provided in different parts of a housing divided into a plurality of parts. Image forming device.

13. The detection unit is provided below the heating unit. The image forming apparatus according to claim 12.

14. A suction section that sucks the medium from a medium storage section that stores the medium; a delivery unit that delivers the medium sucked by the suction unit; a detection unit that detects a leading end and a trailing end of the medium in a state where the medium is stopped and pulled in a pulling direction along the transport path along which the medium sent out by the delivery unit is transported; an image forming unit that forms an image on the medium detected by the detection unit; an upstream transport unit that transports the medium in the transport path in a transport direction and stops the transport; a downstream transport unit that is disposed downstream in a transport direction relative to the upstream transport unit and that transports the medium in the transport path in the transport direction and stops the transport; Equipped with The medium is a medium that may bend during transportation, the upstream transport unit and the downstream transport unit pull the medium in the pulling direction; The detection unit detects the leading end and the trailing end of the medium when the leading end and the trailing end pass through the sending unit and are positioned between the sending unit and the image forming unit. Image forming device.

15. A transport path along which multiple types of media are transported; a detection device that detects the leading and trailing edges of the plurality of types of media in a state where the media is stopped from being conveyed and is pulled in a pulling direction along the conveyance path; an image forming unit that forms images on the plurality of types of media based on the detection result of the detection device; an upstream transport unit that transports the medium in the transport path in a transport direction and stops the transport; a downstream transport unit that is disposed downstream in a transport direction relative to the upstream transport unit and that transports the medium in the transport path in the transport direction and stops the transport; Equipped with The medium is a medium that may bend during transportation, the upstream transport unit and the downstream transport unit pull the medium in the pulling direction; The detection device changes the tension force depending on the type of the medium. Image forming device.

Images