JP2025066011A - Pulley, document transport device and image forming apparatus - Google Patents

Abstract

To provide a pulley for actualizing easy mounting work.SOLUTION: The pulley includes a belt suspension part rotatable around the shaft of a shaft part extending in one direction, and a flange 633 having a larger outer diameter than the belt suspension part, the flange 633 including a first hole formation part forming part of a first hole having an inner diameter larger than the outer diameter at the bottom of an annular groove formed in the shaft part and extending in the peripheral direction and smaller than the outer diameter of the shaft part, and a connection hole formation part forming part of a connection hole 85, the connection hole 85 including a second hole 92 linked with the first hole 91 and having an inner diameter larger than the outer diameter of the shaft part, part of the flange 633 being constructed to be elastically deformable so that a distance between two connection portions 96, 97 via which the first hole formation part and the second hole formation part are connected is changed from the state of being smaller than the outer diameter of the shaft part to the state of being larger.SELECTED DRAWING: Figure 6

Description

This invention relates to a pulley, a document transport device, and an image forming device, and in particular to a pulley that suspends a belt, a document transport device equipped with the pulley, and an image forming device equipped with the document transport device.

Image forming devices, such as MFPs (Multi Function Peripherals), use rollers to transport documents or paper. In addition, belts and pulleys are used to transmit the torque of a motor to the rollers. These pulleys are rotatable around a rotation axis and are fixed in the axial direction. Techniques for fixing the pulley in the axial direction are known.

For example, Japanese Patent Application Laid-Open No. 2003-74674 describes a pulley that includes a belt suspension section on which a belt is hung, a shaft section that protrudes from the belt suspension section in the direction of the rotation axis and has an annular groove that extends in the circumferential direction, and flanges that are provided on both outer sides of the belt suspension section in the direction of the rotation axis and have an outer diameter larger than the outer diameter of the belt suspension section, at least one of the flanges has a through hole into which the shaft section is inserted and has an inner diameter larger than the outer diameter of the shaft section at the bottom of the annular groove and smaller than the outer diameter of the shaft section at the edge of the annular groove, and is elastically deformable and fitted into the annular groove.

To fit the pulley described in JP 2003-74674 A into the annular groove, the worker must move the pulley in the direction of the rotation axis relative to the shaft. This operation causes the pulley to elastically deform in the direction of the rotation axis.

However, the inner diameter of the through hole is smaller than the outer diameter of the shaft at the edge of the annular groove formed in the shaft. This makes it difficult to align the pulley with respect to the shaft. If the through hole and the shaft are misaligned, or if a force that crosses the axial direction of the shaft acts on the pulley, an even force will not act on the periphery of the through hole. This means that a large force will act on a portion of the periphery of the through hole, causing that portion to deform too much, which may result in plastic deformation.

JP 2003-74674 A

One of the objectives of this invention is to provide a pulley that is easy to install.

Another object of the present invention is to provide a document transport device that is easy to manufacture.

Another object of the present invention is to provide an image forming device that is easy to manufacture.

According to one aspect of the invention, the pulley comprises a belt suspension part that can rotate around the axis of the shaft part that extends in one direction, and a flange with an outer diameter larger than the outer diameter of the belt suspension part, the flange comprises a first hole forming part that forms a part of a first hole with an inner diameter larger than the outer diameter at the bottom of a circumferentially extending annular groove formed in the shaft part and smaller than the outer diameter of the shaft part, and a connection hole forming part that forms a part of a connection hole, the connection hole includes a second hole that is connected to the first hole and has an inner diameter larger than the outer diameter of the shaft part, and the part of the flange is configured to be elastically deformable so that the distance between two connection parts where the first hole forming part and the second hole forming part are connected changes from a state smaller than the outer diameter of the shaft part to a state larger than the outer diameter of the shaft part.

According to another aspect of the invention, the document transport device includes the above-mentioned pulley, a drive source that rotates the belt, and a roller to which the rotational force of the pulley is transmitted and which transports the document placed on the document tray.

According to yet another aspect of the present invention, an image forming apparatus includes the above-mentioned document transport device, a document reading device that optically reads a document transported by the document transport device, and an image forming section that forms an image obtained by reading the document by the document reading device on a recording medium.

FIG. 2 is a perspective view showing an example of the appearance of an MFP. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the MFP. FIG. 2 is a diagram illustrating an example of an internal configuration of a document transport device. FIG. 2 is a diagram illustrating an example of a power transmission system in the document transport device. FIG. 4 is a plan view showing a detailed configuration of a third pulley and a fourth pulley. FIG. 4 is a plan view of the second flange. FIG. FIG. 4 is a perspective view of a third pulley attached to a shaft portion. FIG. 4 is a cross-sectional view of a third pulley attached to a shaft portion. 11 is a diagram showing an example of a positional relationship between a second flange and a shaft portion in a first step. FIG. 13 is a diagram showing an example of a positional relationship between a second flange and a shaft portion in a third step. FIG. 13 is a diagram showing an example of the positional relationship between the second flange and the shaft portion at the end of a third process. FIG. FIG. 11 is a plan view of a second flange in the first modified example. FIG. 13 is a perspective view of a second flange in the first modified example. FIG. 11 is a plan view of a second flange in a second modified example. FIG. 13 is a perspective view of a second flange in a second modified example.

Below, an embodiment of the present invention will be described with reference to the drawings. In the following description, identical parts are given the same reference numerals. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

Figure 1 is a perspective view showing an example of the exterior of an MFP. Figure 2 is a schematic cross-sectional view showing the internal configuration of an MFP. Some of the drawings following Figure 1 are marked with arrows indicating the mutually orthogonal X, Y, and Z directions. The X and Y directions are mutually orthogonal in a horizontal plane, and the Z direction corresponds to the vertical direction.

Referring to Figs. 1 and 2, MFP 100 is an example of an image forming device. MFP 100 includes document reading unit 130 for reading a document, document transport device 120 for transporting the document to document reading unit 130, image forming unit 140 for forming an image on paper or the like based on image data, paper feed unit 150 for supplying paper to image forming unit 140, and operation panel 160 as a user interface.

The document transport device 120 automatically transports multiple documents set on the document tray 125 one by one to the document reading position of the document reading unit 130. The document transport device 120 is equipped with a motor and a roller that rotates when the driving force of the motor is transmitted, along the transport path along which the document is transported. When the motor drives the roller, the roller rotates and the document is transported along the transport path. Details of the drive system of the document transport device 120 will be described later.

The document reading unit 130 includes a first document glass 11, a second document glass 12, a line sensor 13, a drive pulley 14, a driven pulley 15, and a belt 16. The first document glass 11 and the second document glass 12 are rectangular, flat glass plates. The size of the first document glass 11 is larger than that of an A3-sized sheet of paper. The length of the first document glass 11 in the longitudinal direction is larger than that of an A3-sized sheet of paper, and the length of the first document glass 11 in the lateral direction is larger than that of an A3-sized sheet of paper. The second document glass 12 is a rectangle extending in the main scanning direction parallel to the Y direction, and the length of the length of the length of the second document glass 12 in the longitudinal direction is longer than that of an A4-sized sheet of paper.

The line sensor 13 has a plurality of photoelectric conversion elements arranged in a line in the main scanning direction parallel to the Y direction. The photoelectric conversion elements are, for example, CCDs (Charge Coupled Devices) or CMOSs (Complementary Metal Oxide Semiconductors). The line sensor 13 is fixed to the belt 16 with the photoelectric conversion elements facing upward. The belt 16 is suspended by the drive pulley 14 and the driven pulley 15 so as not to slacken. The driving force of the motor 17 is transmitted to the drive pulley 14. Therefore, when the motor 17 is driven, the drive pulley 14 rotates. The rotational force of the drive pulley 14 is transmitted to the driven pulley 15 via the belt 16. Therefore, when the motor 17 is driven, the line sensor 13 moves in the sub-scanning direction.

The document reading unit 130 reads the image formed on the document using two different methods. The first type of reading method is a method in which the line sensor 13 reads the image formed on the document while moving the line sensor 13 in the sub-scanning direction parallel to the X direction. The second type of reading method is a method in which the line sensor 13 reads the image formed on the document while the document transport device 120 transports the document, with the position of the line sensor 13 fixed.

When reading an image formed on a document using the first type of reading method, the document reading unit 130 drives the motor 17 to move the line sensor 13 in the sub-scanning direction below the first document glass 11. While moving in the sub-scanning direction, the line sensor 13 scans the image formed on the document in the main scanning direction while also scanning in the sub-scanning direction.

When reading an image formed on a document using the second type of reading method, the document reading unit 130 drives the motor 17 to move the line sensor 13 below the second document glass 12. While the document transported by the document transport device 120 passes above the second document glass 12, the line sensor 13 scans the image formed on the document in the main scanning direction and the sub-scanning direction.

The line sensor 13 outputs image data as an electrical signal while scanning the image formed on the original. The image data output by the line sensor 13 includes image data for each of red (R), green (G), and blue (B). The image data output by the line sensor 13 is output to the image forming unit 140. When the image data output by the line sensor 13 is input to the image forming unit 140, the image data is converted into data for printing. The image data output by the line sensor 13 may be stored in a storage device or may be transmitted externally.

Image forming section 140 includes image forming units 20Y, 20M, 20C, and 20K for yellow, magenta, cyan, and black, respectively. Here, "Y", "M", "C", and "K" stand for yellow, magenta, cyan, and black, respectively. Print data for yellow, magenta, cyan, and black is input to image forming units 20Y, 20M, 20C, and 20K, respectively. Image forming units 20Y, 20M, 20C, and 20K differ only in the color of the toner they handle, so here we will explain image forming unit 20Y for forming a yellow image.

The image forming unit 20Y includes an exposure device 21Y, a photoconductor drum 23Y which is an image carrier, a main charger 22Y, a developing device 24Y, a transfer charger 25Y, a toner bottle 41Y, and a toner hopper 42Y.

The exposure device 21Y emits light according to image data (electrical signals) and exposes the surface of the photoreceptor drum 23Y, which is rotated by a motor. The motor that drives the photoreceptor drum 23Y receives a load from the photoreceptor drum 23Y. After the photoreceptor drum 23Y is charged by the main charger 22Y, it is irradiated with laser light emitted by the exposure device 21Y. This forms an electrostatic latent image on the photoreceptor drum 23Y.

Then, the developer 24Y deposits toner supplied from the toner bottle 41Y onto the electrostatic latent image to form a toner image. The toner image formed on the photoconductor drum 23Y is transferred onto the intermediate transfer belt 30 by the transfer charger 25Y.

Meanwhile, the intermediate transfer belt 30 is suspended by a drive roller 33A and a driven roller 33C so as not to slacken. The drive roller 33A rotates by the driving force of a motor being transmitted to it. When the drive roller 33A rotates counterclockwise in FIG. 3, the intermediate transfer belt 30 rotates counterclockwise in the figure at a predetermined speed. As the intermediate transfer belt 30 rotates, the driven roller 33C rotates counterclockwise. The drive roller 33A receives a load from the intermediate transfer belt 30. The motor that drives the drive roller 33A receives a load from the drive roller 33A.

As a result, image forming units 20Y, 20M, 20C, and 20K transfer toner images onto intermediate transfer belt 30 in sequence. The timing at which each of image forming units 20Y, 20M, 20C, and 20K transfers a toner image onto intermediate transfer belt 30 is adjusted by detecting the reference marks on intermediate transfer belt 30. As a result, yellow, magenta, cyan, and black toner images are superimposed on intermediate transfer belt 30.

The toner image formed on the intermediate transfer belt 30 is transferred to the paper by the transfer roller 26. The paper with the toner image transferred to it is transported to the pair of fixing rollers 32. The pair of fixing rollers 32 includes a heating roller having a heat source, and a pressure roller that is pressed against the heating roller with a certain force. The pressure roller rotates when the driving force of the motor is transmitted to it. The motor that drives the pressure roller receives a load from the pressure roller. While the paper passes between the heating roller and the pressure roller, the toner formed on the paper is heated by the heating roller and pressurized by the pressure roller. This melts the toner and fixes it to the paper. The paper is then discharged to the paper output tray 159.

A removal device 28 is provided upstream of the image forming unit 20Y on the intermediate transfer belt 30. The removal device 28 removes toner remaining on the intermediate transfer belt 30.

Different sizes of paper are set in the paper feed cassettes 35, 35A, and 35B. The paper stored in the paper feed cassettes 35, 35A, and 35B is supplied to the transport path by the take-out rollers 36, 36A, and 36B attached to the paper feed cassettes 35, 35A, and 35B, respectively, and sent to the timing rollers 31 by the paper feed roller 37. The take-out rollers 36, 36A, and 36B, the paper feed roller 37, and the timing roller 31 are rotated by the driving force of the motor. The motor that drives the paper feed roller 37 receives a load from the paper feed roller 37.

When forming a full-color image, the MFP 100 drives all of the image forming units 20Y, 20M, 20C, and 20K. When forming a monochrome image, the MFP 100 drives any one of the image forming units 20Y, 20M, 20C, and 20K. The MFP 100 can also form an image by combining two or more of the image forming units 20Y, 20M, 20C, and 20K. The image forming section 140 is of a tandem type equipped with the image forming units 20Y, 20M, 20C, and 20K that form toner of each of the four colors on the paper. The image forming section 140 may be of a four-cycle type that transfers the toner of each of the four colors to one photosensitive drum onto the paper in sequence.

Figure 3 is a diagram showing an example of the internal configuration of the document transport device. With reference to Figure 3, the document transport device 120 includes a pick roller 51, a first transport roller 52, a registration roller 53, a second transport roller 54, a third transport roller 55, a discharge roller 56, and a back-side line sensor 57.

The pick roller 51, the first transport roller 52, the registration roller 53, the second transport roller 54, the third transport roller 55 and the discharge roller 56 are each cylindrical. The pick roller 51, the first transport roller 52, the registration roller 53, the second transport roller 54, the third transport roller 55 and the discharge roller 56 are each supported by a frame 120A (described later) of the document transport device 120 with their rotational axes parallel to the sub-scanning direction. The pick roller 51, the first transport roller 52, the registration roller 53, the second transport roller 54, the third transport roller 55 and the discharge roller 56 are each arranged along the document transport path indicated by the dotted arrow in the figure.

The pick roller 51, the first conveyor roller 52, the registration roller 53, the second conveyor roller 54, the third conveyor roller 55 and the discharge roller 56 each receive a rotational force from a motor M (see FIG. 4) described later and rotate. A clutch may be disposed between the pick roller 51, the first conveyor roller 52, the registration roller 53, the second conveyor roller 54, the third conveyor roller 55 and the discharge roller 56 and the motor M. By opening and closing the clutch, the timing at which the rotational force of the motor M is transmitted to the pick roller 51, the first conveyor roller 52, the registration roller 53, the second conveyor roller 54, the third conveyor roller 55 and the discharge roller 56 can be made independent.

Of the multiple documents placed on the document tray 125, the topmost document is transported by the pick roller 51. The document transported by the pick roller 51 proceeds along the document transport path toward the first transport roller 52. The document that reaches the first transport roller 52 is transported by the first transport roller 52.

A first sub-conveyor roller 52A is provided opposite the first conveyor roller 52. The first sub-conveyor roller 52A is cylindrical and is arranged with its rotational symmetry axis parallel to the rotational axis of the first conveyor roller 52. The first sub-conveyor roller 52A is rotatable around its rotational symmetry axis, which is biased toward the first conveyor roller 52. The original document, sandwiched between the first conveyor roller 52 and the first sub-conveyor roller 52A, advances along the original document conveying path toward the registration roller 53. The original document that reaches the registration roller 53 is conveyed by the registration roller 53.

The sub-registration roller 53A is provided opposite the registration roller 53. The sub-registration roller 53A is cylindrical and is arranged with its rotational symmetry axis parallel to the rotational axis of the registration roller 53. The sub-registration roller 53A is rotatable around its rotational symmetry axis, which is biased toward the registration roller 53. The original is sandwiched between the registration roller 53 and the sub-registration roller 53A and travels along the original transport path toward the second transport roller 54. The original that reaches the second transport roller 54 is transported by the second transport roller 54.

A second sub-transport roller 54A is provided opposite the second transport roller 54. The second sub-transport roller 54A is cylindrical and is arranged with its rotational symmetry axis parallel to the rotational axis of the second transport roller 54. The second sub-transport roller 54A is rotatable around its rotational symmetry axis, which is biased toward the second transport roller 54. The original document is sandwiched between the second transport roller 54 and the second sub-transport roller 54A and travels along the original transport path toward the third transport roller 55.

The document reading position is determined between the second transport roller 54 and the third transport roller 55 on the document transport path. The document reading position is above the second document glass 12. While the document transported by the second transport roller 54 passes through the document reading position, the document is scanned in the main scanning direction and the sub-scanning direction by the line sensor 13.

The document that reaches the third transport roller 55 is transported by the third transport roller 55. A third sub-transport roller 55A is provided opposite the third transport roller 55. The third sub-transport roller 55A is cylindrical and is arranged with its rotational symmetry axis parallel to the rotational axis of the third transport roller 55. The third sub-transport roller 55A is rotatable around its rotational symmetry axis, which is biased toward the third transport roller 55. The document advances along the document transport path toward the discharge roller 56 while being sandwiched between the third transport roller 55 and the third sub-transport roller 55A.

The document that reaches the discharge roller 56 is transported by the discharge roller 56. A secondary discharge roller 56A is provided opposite the discharge roller 56. The secondary discharge roller 56A is cylindrical and is arranged with its rotational symmetry axis parallel to the rotational axis of the discharge roller 56. The secondary discharge roller 56A is rotatable around its rotational symmetry axis, which is biased toward the discharge roller 56. The document is sandwiched between the discharge roller 56 and the secondary discharge roller 56A and discharged to the document discharge tray 127.

Figure 4 is a diagram showing an example of a power transmission system in a document transport device. For ease of explanation, Figure 4 shows the power transmission system from motor M to first transport roller 52, registration roller 53, second transport roller 54, and discharge roller 56. The power transmission system from motor M to pick roller 51 and third transport roller 55 is not shown, but power is transmitted from motor M to them.

Referring to FIG. 4, the rotation shaft AX of the motor M is connected to the first pulley 61 by a first belt 81. The first pulley 61 has a gear that meshes with a gear of the second pulley 62. This allows the rotational force of the motor M to be transmitted to the second pulley 62 via the first pulley 61.

The gear of the third pulley 63 meshes with the first gear 71. The second gear 72 meshes with the first gear 71 and the third gear 73. The third gear 73 meshes with the fourth gear 74. The rotation shaft of the fourth gear 74 is connected to the rotation shaft of the first conveyor roller 52. Therefore, the rotation force of the second pulley 62 is transmitted to the first conveyor roller 52 via the first gear 71, the second gear 72, the third gear 73, and the fourth gear 74.

The first gear 71 meshes with a gear of the third pulley 63. The third pulley 63 is connected to the fourth pulley 64 by the second belt 82. The gear of the fourth pulley 64 meshes with a fifth gear 75. The rotation shaft of the fifth gear 75 is connected to the rotation shaft of the registration roller 53. Therefore, the rotation force of the second pulley 62 is transmitted to the registration roller 53 via the first gear 71, the third pulley 63, the fourth pulley 64, and the fifth gear 75.

The fifth pulley 65 is connected to the second pulley 62 by a third belt 83. The gear of the fifth pulley 65 meshes with the sixth gear 76. The rotation shaft of the sixth gear 76 is connected to the rotation shaft of the second conveyor roller 54. Therefore, the rotation force of the second pulley 62 is transmitted to the second conveyor roller 54 via the fifth pulley 65 and the sixth gear 76.

The sixth pulley 66 is connected to the second pulley 62 by a fourth belt 84. The rotation shaft of the sixth pulley 66 is connected to the rotation shaft of the discharge roller 56. Therefore, the rotation force of the second pulley 62 is transmitted to the discharge roller 56 via the sixth pulley 66.

Figure 5 is a plan view showing the detailed configuration of the third pulley and the fourth pulley. Referring to Figure 5, the third pulley 63 is attached to the shaft portion 123 extending in the Y direction from the frame 120A of the document transport device 120 in a rotatable state around the shaft portion 123.

The third pulley 63 and the fourth pulley 64 have the same configuration, so the third pulley 63 will be mainly described as an example. The third pulley 63 includes a belt suspension portion 631, a first flange 632, and a second flange 633.

The belt suspension part 631 has a flat cylindrical shape with a hole formed in the center. The shaft part 123 is inserted into the hole of the belt suspension part 631, so that the belt suspension part 631 is rotatably attached to the shaft part 123. A groove is formed on the side of the belt suspension part 631, which engages with a rack formed on the inner surface of the second belt 82. This prevents slippage between the belt suspension part 631 and the second belt 82.

The first flange 632 has a flat cylindrical shape with a hole formed in the center. The shaft portion 123 is inserted into the hole in the first flange 632, so that the first flange 632 is rotatably attached to the shaft portion 123. The outer diameter of the first flange 632 is larger than the outer diameter of the belt suspension portion 631. Teeth are formed on the side of the first flange 632 to mesh with the first gear 71. This allows the rotational force of the first gear 71 to be transmitted to the first flange 632.

The first flange 632 is attached to the shaft portion 123 on the frame 120A side of the belt suspension portion 631. In addition, the first flange 632 and the belt suspension portion 631 rotate integrally around the shaft portion 123 while attached to the shaft portion 123. Therefore, the rotational force of the first flange 632 is transmitted to the belt suspension portion 631. The belt suspension portion 631 and the first flange 632 may be integrally formed from the same member.

The second flange 633 is made of resin and has a flat cylindrical shape. The outer diameter of the second flange 633 is larger than the outer diameter of the belt suspension part 631. The second flange 633 is fitted into an annular groove 123A (see FIG. 9) extending in the circumferential direction formed on the shaft part 123 on the opposite side of the frame 120A with respect to the belt suspension part 641. This allows the second flange 633 to be attached to the shaft part 123. Since the second flange 633 is fitted into the annular groove 123A of the shaft part 123, the axial movement of the shaft part 123 is restricted. Therefore, the second flange 633 restricts the movement of the belt suspension part 631 and the first flange 632 in the axial direction of the shaft part 123.

In the third pulley 63, the outer diameters of the first flange 632 and the second flange 633 are larger than the outer diameter of the belt suspension portion 631. The belt suspension portion 631 is disposed between the first flange 632 and the second flange 633. In the fourth pulley 64, the outer diameters of the first flange 642 and the second flange 643 are larger than the outer diameter of the belt suspension portion 641. The belt suspension portion 641 is disposed between the first flange 642 and the second flange 643. This allows the second belt 82 to be maintained in a state in which it is suspended by the belt suspension portion 631 of the second pulley 62 and the belt suspension portion 641 of the fourth pulley 64.

The third pulley 63 has a first flange 632 to which a rotational force is transmitted from the first gear 71, and the rotational force is transmitted from the first flange 632 to the belt suspension part 631. When the belt suspension part 631 rotates, the second belt 82 rotates. The fourth pulley 64 has a belt suspension part 641 to which a rotational force is transmitted from the second belt 82, and the rotational force is transmitted from the belt suspension part 641 to the first flange 642. The teeth formed on the side of the first flange 642 mesh with the fifth gear 75, so the rotational force of the first flange 642 is transmitted to the fifth gear 75.

Figure 6 is a plan view of the second flange. Figure 7 is a perspective view of the second flange. With reference to Figures 6 and 7, the second flange 633 of the third pulley 63 includes a main body portion 98 and an outer edge portion 99. The outer edge portion 99 is a circular ring portion at a predetermined distance from the outer periphery of the second flange 633, and has a cylindrical shape. The main body portion 98 is a flat plate located inside the outer edge portion 99, and has a cylindrical shape. The thickness of the outer edge portion 99 is greater than the thickness of the main body portion 98.

The main body 98 has a first hole 91, a second hole 92, and a notch 93. The first hole 91 is a circular hole that penetrates the main body 98. The center of the first hole 91 overlaps with the center of the second flange 633. The second hole 92 is an example of a connection hole 85. The second hole 92 is a circular hole that penetrates the main body 98. The second hole 92 is formed at a position where a part of the second hole 92 overlaps with the first hole 91. The inner diameter of the second hole 92 is larger than the inner diameter of the first hole 91. The inner diameter of the second hole 92 is also larger than the outer diameter of the shaft 123. The amount of overlap between the first hole 91 and the second hole 92 (connection hole 85) is smaller than 1/2 of the inner diameter of the first hole 91 in the radial direction of the first hole 91.

The notch 93 penetrates the main body 98. The notch 93 includes a first side 86A, a second side 86B, and a connecting portion 86C that connects the first side 86A, the second side 86B, and the first hole 91. The connecting portion 86C connects the first side 86A to the first hole 91, and also connects the second side 86B to the first hole 91. The first side 86A and the second side 86B are formed on both sides of the first hole 91 and a portion of the second hole 92. A portion of the second hole 92 includes a portion that overlaps with the first hole 91. The first hole 91 and a portion of the connecting hole 85A are disposed between the first side 86A and the second side 86B, and are sandwiched between the first side 86A and the second side 86B.

The main body portion 98 includes a first elastic deformation portion 94 and a second elastic deformation portion 95. The first elastic deformation portion 94 is a portion of the main body portion 98 surrounded by the first hole 91, the second hole 92, the first side portion 86A, and the connecting portion 86C. The second elastic deformation portion 95 is a portion of the main body portion 98 surrounded by the first hole 91, the second hole 92, the second side portion 86B, and the connecting portion 86C.

The portion of the first elastic deformation portion 94 that contacts the first hole 91 and the portion of the second elastic deformation portion 95 that contacts the first hole 91 are the first hole forming portions. The portion of the first elastic deformation portion 94 that contacts the second hole 92 and the portion of the second elastic deformation portion 95 that contacts the second hole 92 are the connection hole forming portions.

The portion where the first hole forming portion of the first elastic deformation portion 94 and the connection hole forming portion meet is the first connection portion 96. The portion where the first hole forming portion of the second elastic deformation portion 95 and the connection hole forming portion meet is the second connection portion 97. The first connection portion 96 and the second connection portion 97 are two points where the outer periphery of the first hole 91 and the outer periphery of the second hole 92 intersect. The distance between the first connection portion 96 and the second connection portion 97 is smaller than the inner diameter of the first hole 91.

Figure 8 is a perspective view of the third pulley mounted on the shaft. Figure 9 is a cross-sectional view of the third pulley mounted on the shaft. Figure 9 shows a cross section cut along a plane passing through the center of the shaft and parallel to the axial direction. With reference to Figures 8 and 9, the shaft 123 is formed with an annular groove 123A extending in the circumferential direction. The inner diameter of the first hole 91 of the second flange 633 shown in Figure 6 is larger than the outer diameter at the bottom of the annular groove 123A and smaller than the outer diameter of the shaft 123. The thickness of the main body 98 of the second flange 633 is smaller than the width of the annular groove 123A. Therefore, the second flange 633 shown in Figure 6 fits into the annular groove 123A of the shaft 123. Specifically, the first hole forming portion, which is a part of each of the first elastic deformation portion 94 and the second elastic deformation portion 95 of the main body 98 of the second flange 633, is fitted into the annular groove 123A.

Figures 10 to 12 are diagrams showing the procedure for attaching the second flange to the shaft portion by an operator. In Figures 10 to 12, a cross section of the bottom of the annular groove 123A of the shaft portion 123 is shown. Figure 10 is a diagram showing an example of the positional relationship between the second flange and the shaft portion in the first step. With reference to Figure 10, the operator grasps the second flange 633 and moves the second flange 633 so that the shaft portion 123 is located inside the second hole 92. First, the operator moves the second flange 633 vertically and horizontally relative to the shaft portion 123 within a plane perpendicular to the axial direction of the shaft portion 123, and moves the second flange 633 to a position where the tip of the shaft portion 123 fits into the second hole 92. Next, the operator moves the second flange 633 axially relative to the shaft portion 123, and moves the second flange 633 to a position where the shaft portion 123 is inserted into the second hole 92. As shown in FIG. 10, the inner diameter of the second hole 92 is larger than the outer diameter of the shaft portion 123. Therefore, the operator can move the second flange 633 to a position where the shaft portion 123 is inserted into the second hole 92 simply by applying a force to the second flange 633 to move the second flange 633 in the axial direction.

In the second step, the worker moves the second flange 633 vertically and horizontally relative to the shaft portion 123 within a plane perpendicular to the axial direction of the shaft portion 123. Specifically, the worker moves the second flange 633 to a position where the first connection portion 96 and the second connection portion 97 of the second flange 633 abut the bottom of the annular groove 123A of the shaft portion 123. In the second step, the worker only needs to apply to the second flange 633 a force that moves the second flange 633.

Figure 11 is a diagram showing an example of the positional relationship between the second flange and the shaft portion in the third step. In the third step, the worker moves the second flange 633 in the direction indicated by the arrow AR1. The arrow AR1 indicates the direction in which the first hole 91 faces the shaft portion 123 in a plane perpendicular to the axial direction of the shaft portion 123. The distance between the first connection portion 96 and the second connection portion 97 of the second flange 633 is smaller than the outer diameter of the bottom of the annular groove 123A of the shaft portion 123. When the worker moves the second flange 633 in the direction indicated by the arrow AR1 in a plane perpendicular to the axial direction of the shaft portion 123, the first connection portion 96 receives a force in the direction indicated by the arrow AR2 from the shaft portion 123, and the second connection portion 97 receives a force in the direction indicated by the arrow AR2 from the shaft portion 123.

The first elastic deformation portion 94 is an area surrounded by the first side portion 86A, the connecting portion 86C, the first hole 91, and a portion of the second hole 92, and includes a first connection portion 96. The second elastic deformation portion 95 is an area surrounded by the second side portion 86B, the connecting portion 86C, the first hole 91, and a portion of the second hole 92, and includes a second connection portion 97. When the first connection portion 96 and the second connection portion 97 receive a force from the shaft portion 123 in a direction moving them away from each other, the first elastic deformation portion 94 and the second elastic deformation portion 95 elastically deform in a direction moving them away from each other. This increases the distance between the first connection portion 96 and the second connection portion 97.

The width of each of the first side portion 86A and the second side portion 86B is determined by the distance between the first connection portion 96 and the second connection portion 97 before and after the first elastic deformation portion 94 and the second elastic deformation portion 95 are elastically deformed. The distance between the first connection portion 96 and the second connection portion 97 is smaller than the outer diameter of the bottom of the annular groove 123A of the shaft portion 123 before the first elastic deformation portion 94 and the second elastic deformation portion 95 are elastically deformed. The distance between the first connection portion 96 and the second connection portion 97 is larger than the outer diameter of the bottom of the annular groove 123A of the shaft portion 123 after the first elastic deformation portion 94 and the second elastic deformation portion 95 are elastically deformed. The first elastic deformation portion 94 elastically deforms toward the first side portion 86A, and after elastic deformation, it blocks a part of the first side portion 86A. The second elastic deformation portion 95 elastically deforms toward the second side portion 86B, and after elastic deformation, blocks a part of the second side portion 86B. The widths of the first side portion 86A and the second side portion 86B are determined based on the distance between the first connection portion 96 and the second connection portion 97 when the first elastic deformation portion 94 and the second elastic deformation portion 95 are in the most elastically deformed state. The distance between the first connection portion 96 and the second connection portion 97 is greater than the outer circumference of the bottom of the annular groove 123A of the shaft portion 123.

In the third step, the worker further moves the second flange 633 in the direction indicated by the arrow AR1. This causes the first connection portion 96 and the second connection portion 97 to overcome the portion of the outer periphery at the bottom of the annular groove 123A of the shaft portion 123 that has the maximum diameter. In this case, the elastic force of the first elastic deformation portion 94 applies a force in the opposite direction to the arrow AR2 to the first connection portion 96, and the elastic force of the second elastic deformation portion 95 applies a force in the opposite direction to the arrow AR3 to the second connection portion 97.

Figure 12 is a diagram showing an example of the positional relationship between the second flange and the shaft portion at the end of the third step. Referring to Figure 12, the shaft portion 123 fits inside the first hole 91. In Figure 12, the outer periphery of the portion of the shaft portion 123 other than the annular groove 123A is shown by a dotted line. The inner diameter of the first hole 91 is larger than the outer periphery of the bottom of the annular groove 123A of the shaft portion 123 and smaller than the outer periphery of the portion of the shaft portion 123 other than the annular groove 123A. Therefore, the first hole forming portion, which is part of the first elastic deformation portion 94 of the second flange 633, and the first hole forming portion, which is part of the second elastic deformation portion 95, fit into the annular groove 123A of the shaft portion 123.

<First Modification>
Fig. 13 is a plan view of the second flange in the first modification. Fig. 14 is a perspective view of the second flange in the first modification. Referring to Figs. 13 and 14, the second flange 633A in the first modification is different from the second flange 633 shown in Figs. 6 and 7 in that the connection hole 85 is changed to a connection hole 85A, the notch 93 is changed to a notch 93A, and the first elastic deformation portion 94 and the second elastic deformation portion 95A are changed to a first elastic deformation portion 94A and a second elastic deformation portion 95A. The other configurations are the same as those of the second flange 633 shown in Figs. 6 and 7, and therefore description thereof will not be repeated here.

The connection hole 85A includes a second hole 92. The inner diameter of the second hole 92 is larger than the inner diameter of the first hole 91. The inner diameter of the second hole 92 is also larger than the outer diameter of the shaft portion 123. The second hole 92 is disposed at a position where a portion of the second hole 92 overlaps with the outer edge portion 99. The connection hole 85A is formed at a position where a portion of the second hole 92 overlaps with the first hole 91.

The notch 93A penetrates the main body 98. The notch 93A includes a first side 86A, a second side 86B, and a connecting portion 86C that connects each of the first side 86A and the second side 86B to the second hole 92. The connecting portion 86C connects the first side 86A to the second hole 92 and also connects the second side 86B to the second hole 92. The first side 86A and the second side 86B are formed on both sides of the first hole 91 and a portion of the second hole 92. The connecting hole 85A includes a portion that overlaps with the first hole 91. The first hole 91 and a portion of the connecting hole 85A are disposed between the first side 86A and the second side 86B, and are sandwiched between the first side 86A and the second side 86B.

The main body 98 includes a first elastic deformation portion 94A and a second elastic deformation portion 95A. The first elastic deformation portion 94A is a portion of the main body 98 surrounded by the first hole 91, the connection hole 85A, the first side portion 86A, and the connecting portion 86C. The second elastic deformation portion 95A is a portion of the main body 98 surrounded by the first hole 91, the connection hole 85A, the second side portion 86B, and the connecting portion 86C.

The portion of the first elastic deformation portion 94A that contacts the first hole 91 and the portion of the second elastic deformation portion 95A that contacts the first hole 91 are the first hole forming portions. The portion of the first elastic deformation portion 94A that contacts the connection hole 85A and the portion of the second elastic deformation portion 95A that contacts the connection hole 85A are the connection hole forming portions.

The first connection portion 96 is the portion where the first hole forming portion of the first elastic deformation portion 94A and the connection hole forming portion meet. The second connection portion 97 is the portion where the first hole forming portion of the second elastic deformation portion 95 and the connection hole forming portion meet. The first connection portion 96 and the second connection portion 97 are two points where the outer periphery of the first hole 91 and the outer periphery of the connection hole 85A intersect. The distance between the first connection portion 96 and the second connection portion 97 is smaller than the inner diameter of the first hole 91. The amount of overlap between the first hole 91 and the connection hole 85A in the radial direction of the first hole 91 is smaller than 1/2 the inner diameter of the first hole 91.

Next, the work of attaching the second flange 633A in the first modified example to the shaft portion 123 will be described. In the first step, the worker grasps the second flange 633A in the first modified example and moves the second flange 633A so that the shaft portion 123 is positioned inside the connection hole 85A.

In the second step, the worker moves the second flange 633A in the first modified example vertically and horizontally relative to the shaft portion 123 within a plane perpendicular to the axial direction of the shaft portion 123. This moves the second flange 633A to a position where the first connection portion 96 and the second connection portion 97 of the second flange 633A abut against the bottom of the annular groove 123A of the shaft portion 123.

In the third step, the worker moves the second flange 633A in the first modified example in a plane perpendicular to the axial direction of the shaft portion 123, in a direction in which the first hole 91 moves toward the shaft portion 123. In the third step, the first elastic deformation portion 94A and the second elastic deformation portion 95A elastically deform in directions away from each other. This increases the distance between the first connection portion 96 and the second connection portion 97.

The width of each of the first side portion 86A and the second side portion 86B is determined by the distance between the first connection portion 96 and the second connection portion 97 before and after the first elastic deformation portion 94A and the second elastic deformation portion 95A are elastically deformed. The distance between the first connection portion 96 and the second connection portion 97 is smaller than the outer diameter of the bottom of the annular groove 123A of the shaft portion 123 before the first elastic deformation portion 94A and the second elastic deformation portion 95A are elastically deformed. The distance between the first connection portion 96 and the second connection portion 97 is larger than the outer diameter of the bottom of the annular groove 123A of the shaft portion 123 after the first elastic deformation portion 94A and the second elastic deformation portion 95A are elastically deformed. The first elastic deformation portion 94A elastically deforms toward the first side portion 86A, and after elastic deformation, it blocks a part of the first side portion 86A. The second elastic deformation portion 95A elastically deforms toward the second side portion 86B, and after elastic deformation, blocks a part of the second side portion 86B. The widths of the first side portion 86A and the second side portion 86B are determined based on the distance between the first connection portion 96 and the second connection portion 97 when the first elastic deformation portion 94A and the second elastic deformation portion 95A are in the most elastically deformed state. The distance between the first connection portion 96 and the second connection portion 97 is greater than the outer circumference of the bottom of the annular groove 123A of the shaft portion 123.

In the third step, the worker further moves the second flange 633A in the first modified example in a plane perpendicular to the axial direction of the shaft portion 123 in a direction in which the first hole 91 faces the shaft portion 123. This causes the first connection portion 96 and the second connection portion 97 to overcome the portion of the outer periphery of the bottom of the annular groove 123A of the shaft portion 123 that has the maximum diameter. In this case, the first hole forming portion of the second flange 633A in the first modified example fits into the annular groove 123A of the shaft portion 123 due to the elastic force of the first elastic deformation portion 94A and the elastic force of the second elastic deformation portion 95A. The first hole forming portion of the second flange 633A in the first modified example is a part of the first elastic deformation portion 94A and a part of the second elastic deformation portion 95A.

<Second Modification>
Fig. 15 is a plan view of the second flange in the second modification. Fig. 16 is a perspective view of the second flange in the second modification. Referring to Figs. 15 and 16, the second flange 633B in the second modification is different from the second flange 633 shown in Figs. 6 and 7 in that it does not have an outer edge portion 99, the cut portion 93 is changed to the first cut portion 87 and the second cut portion 88, and the first elastic deformation portion 94 and the second elastic deformation portion 95A are changed to the first elastic deformation portion 94B and the second elastic deformation portion 95B. The other configurations are the same as those of the second flange 633 shown in Figs. 6 and 7, and therefore description thereof will not be repeated here.

The first cutout 87 and the second cutout 88 penetrate the main body 98. The first cutout 87 connects the second hole 92 (connection hole 85) to the outer periphery of the main body 98. The second cutout 88 extends from the first hole 91 in the opposite direction to the second hole 92.

The main body portion 98 includes a first elastic deformation portion 94B and a second elastic deformation portion 95B. The first elastic deformation portion 94B is a portion of the main body portion 98 that is surrounded by the first hole 91, the second hole 92, the second cut portion 88, the first cut portion 87, and the outer periphery of the main body portion 98. The second elastic deformation portion 95A is a portion of the main body portion 98 that is surrounded by the first hole 91, the second hole 92, the second cut portion 88, the first cut portion 87, and the outer periphery of the main body portion 98.

The portion of the first elastic deformation portion 94B that contacts the first hole 91 and the portion of the second elastic deformation portion 95B that contacts the first hole 91 are the first hole forming portions. The portion of the first elastic deformation portion 94A that contacts the second hole 92 (connection hole 85) and the portion of the second elastic deformation portion 95A that contacts the second hole 92 (connection hole 85) are the connection hole forming portions.

The first connection portion 96 is the portion where the first hole forming portion of the first elastic deformation portion 94B and the connection hole forming portion meet. The second connection portion 97 is the portion where the first hole forming portion of the second elastic deformation portion 95B and the connection hole forming portion meet. The first connection portion 96 and the second connection portion 97 are two points where the outer periphery of the first hole 91 and the outer periphery of the second hole 92 (connection hole 85) intersect. The distance between the first connection portion 96 and the second connection portion 97 is smaller than the inner diameter of the first hole 91. The amount of overlap between the first hole 91 and the second hole 92 (connection hole 85) in the radial direction of the first hole 91 is smaller than 1/2 the inner diameter of the first hole 91.

The following describes the procedure for attaching the second flange 633B of the second modified example to the shaft portion 123. In the first step, the worker grasps the second flange 633B of the second modified example and moves the second flange 633B so that the shaft portion 123 is positioned inside the connection hole 85.

In the second step, the worker moves the second flange 633B in the second modified example vertically and horizontally relative to the shaft portion 123 within a plane perpendicular to the axial direction of the shaft portion 123. This moves the second flange 633B to a position where the first connection portion 96 and the second connection portion 97 of the second flange 633B abut against the bottom of the annular groove 123A of the shaft portion 123.

In the third step, the worker moves the second flange 633B in the second modified example in a plane perpendicular to the axial direction of the shaft portion 123, in a direction in which the first hole 91 faces the shaft portion 123. In the third step, the first elastic deformation portion 94B and the second elastic deformation portion 95B elastically deform in directions away from each other. This increases the distance between the first connection portion 96 and the second connection portion 97.

In the third step, the worker further moves the second flange 633B in the second modified example in a plane perpendicular to the axial direction of the shaft portion 123, in the direction in which the first hole 91 faces the shaft portion 123. This causes the first connection portion 96 and the second connection portion 97 to overcome the portion of the outer periphery of the bottom of the annular groove 123A of the shaft portion 123 that has the maximum diameter. The first hole forming portion fits into the annular groove 123A of the shaft portion 123 due to the elastic force of the first elastic deformation portion 94B and the elastic force of the second elastic deformation portion 95B. The first hole forming portion is a part of the first elastic deformation portion 94B and a part of the second elastic deformation portion 95B of the second flange 633B in the second modified example.

As described above, the third pulley 63 in this embodiment includes a belt suspension portion 631 that can rotate around the axis of the shaft portion 123 extending in one direction, and a second flange 633 having an outer diameter larger than the outer diameter of the belt suspension portion 631. The second flange 633 includes a first hole forming portion and a connection hole forming portion. The first hole forming portion forms a part of a first hole 91 having an inner diameter larger than the outer diameter at the bottom of the annular groove 123A extending in the circumferential direction formed in the shaft portion 123 and smaller than the outer diameter of the shaft portion 123. The connection hole forming portion forms a part of a connection hole 85. The connection hole 85 includes a second hole 92 that is connected to the first hole 91 and has an inner diameter larger than the outer diameter of the shaft portion 123. The first elastic deformation portion 94 and the second elastic deformation portion 95 of the second flange 633 are configured to be elastically deformable so that the distance between the first connection portion 96 and the second connection portion 97, which connect the first hole forming portion and the connection hole forming portion, changes from a state smaller than the outer diameter of the shaft portion 123 to a state larger than the outer diameter of the shaft portion 123.

Since the connection hole 85 includes a second hole 92 having an inner diameter larger than the outer diameter of the shaft portion 123, the shaft portion 123 can be passed through the connection hole 85. The connection hole 85 is connected to the first hole 91. The first elastic deformation portion 94 and the second elastic deformation portion 95 of the second flange 633 are configured to be elastically deformable so that the distance between the first connection portion 96 and the second connection portion 97, where the first hole forming portion and the second hole forming portion are connected, is changed from a state smaller than the outer diameter of the shaft portion 123 to a state larger than the outer diameter of the shaft portion 123. Therefore, the shaft portion 123 passing through the connection hole 85 can be moved to the first hole 91. The first hole forming portion forms a part of the first hole 91 having an inner diameter larger than the outer diameter at the bottom of the annular groove 123A formed in the shaft portion 123 and smaller than the outer diameter of the shaft portion 123. The first hole forming portion fits into the annular groove 123A formed in the shaft portion 123. Therefore, the second flange 633 fits into the annular groove 123A, and the second flange 633 itself is fixed to the annular groove 123A that is set in the axial direction of the shaft portion 123. As a result, the worker can easily attach the second flange 633 to the shaft portion 123.

The second flange 633 also has a cutout portion 93, which includes a first side portion 86A and a second side portion 86B that are two cutouts that sandwich at least a part of the first hole 91 and the connection hole 85 between them. This allows the flange to elastically deform the first elastic deformation portion 94 and the second elastic deformation portion 95, which are two parts sandwiched between the first hole 91 and the connection hole 85 and the first side portion 86A and the second side portion 86B, respectively. This makes it easier to expand the inner diameter of the first hole 91 and the connection hole 85. Similarly, the second flange 633A in the first modified example has a cutout portion 93A, which includes a first side portion 86A and a second side portion 86B that are two cutouts that sandwich at least a part of the first hole 91 and the connection hole 85A between them. This allows the flange to elastically deform the first elastic deformation portion 94A and the second elastic deformation portion 95A, which are the two portions sandwiched between the first hole 91 and the connection hole 85A and the first side portion 86A and the second side portion 86B, respectively. This makes it easier to enlarge the inner diameter of the first hole 91 and the connection hole 85A.

In addition, the second flange 633 further includes a connecting portion 86C that connects the first side portion 86A and the second side portion 86B, which are two notches, to the first hole 91. The connecting portion 86C connects the first side portion 86A to the first hole 91, and also connects the second side portion 86B to the first hole 91. A first elastic deformation portion 94 surrounded by the first hole 91, the connecting hole 85, and the first side portion 86A and a second elastic deformation portion 95 surrounded by the first hole 91, the connecting hole 85, and the second side portion 86B are formed. Therefore, the force that elastically deforms the first elastic deformation portion 94 can be reduced, and the force that elastically deforms the second elastic deformation portion 95 can be reduced. Similarly, the second flange 633A in the first modified example further includes a connecting portion 86C that connects the first side portion 86A and the second side portion 86B, which are two notches, to the connection hole 85A. The connecting portion 86C connects the first side portion 86A to the connection hole 85A, and also connects the second side portion 86B to the connection hole 85A. A first elastic deformation portion 94A surrounded by the first hole 91, the connection hole 85A, and the first side portion 86A, and a second elastic deformation portion 95A surrounded by the first hole 91, the connection hole 85A, and the second side portion 86B are formed. The force that elastically deforms the first elastic deformation portion 94A can be reduced, and the force that elastically deforms the second elastic deformation portion 95A can be reduced.

The second flange 633B in the second modified example further includes a first cutout 87 that connects the second hole 92 and the outer periphery of the second flange 633B. Since the second hole 92 and the outer periphery of the second flange 633B are connected by the first cutout 87, the second flange 633B is divided into two parts, the first elastic deformation part 94B and the second elastic deformation part 95B, by the first hole 91, the second hole 92, and the first cutout 87. This makes it possible to reduce the force that elastically deforms the first elastic deformation part 94B and the second elastic deformation part 95B.

The center of the first hole 91 also overlaps with the center of rotation of the second flanges 633A, 633A, 633B. This allows the centers of the second flanges 633A, 633A, 633B to coincide with the axis of the shaft portion 123, allowing the second flanges 633A, 633A, 633B to rotate stably around the shaft portion 123.

The second flanges 633A, 633A, and 633B are also made of resin. This makes it easier to manufacture the second flanges 633A, 633A, and 633B.

The document transport device 120 also includes a second flange 633, a motor M that rotates the belt suspension part 631, and a pick roller 51, a first transport roller 52, a registration roller 53, a second transport roller 54, a third transport roller 55, and a discharge roller 56 to which the rotational force of the belt suspension part 631 is transmitted to transport the document placed on the document tray 125. This makes it easy to manufacture the document transport device.

The MFP 100 also includes a document transport device 120, a document reading unit 130 that optically reads the document transported by the document transport device 120, and an image forming unit 140 that forms an image obtained by reading the document by the document reading unit 130 on a recording medium. This makes it easy to manufacture the MFP 100.

<Other embodiments>
(1) In the above-described embodiment, the third pulley 63 has been described as an example, but the first pulley 61, the second pulley 62, the fourth pulley 64, the fifth pulley 65 and the sixth pulley 66 can each be configured in a similar manner to the third pulley 63.

In addition, the present invention is not limited to the pulleys used in the document transport device 120, as long as they are pulleys that suspend a belt. For example, the present invention can be applied to the drive pulley 14 and the driven pulley 15 of the document reading unit 130. In addition, when a belt is used to drive the timing roller 31, the fixing roller pair 32, the drive roller 33A, the driven roller 33C, etc., which are provided in the image forming unit 140, the present invention may be applied to the pulleys used in the power transmission system thereof. In addition, there are cases where a belt is used to operate the toner bottles 41M, 41M, 41C, 41K, the toner hoppers 42Y, 42M, 42C, 42K, the photoconductor drums 23Y, 23M, 23C, 23K, and the developers 24Y, 24M, 24C, 24K. In this case, the present invention may be applied to the pulleys used in the power transmission system thereof. Furthermore, in the case where a belt is used to rotate the take-out rollers 36, 36A, 36B, the feed roller 37, etc., which are provided in the feed unit 150, the present invention may be applied to pulleys used in the power transmission system thereof.
, can be applied.

(2) In this embodiment, an example has been described in which the second flange 633 is formed from resin, but the present invention is not limited to this. The second flange 633 may be formed from a material that has a predetermined hardness and is elastically deformable. The second flange 633 may be formed from a metal such as stainless steel, for example.

<Summary of the embodiment>
(Item 1) A belt suspension part that can rotate around an axis of a shaft part extending in one direction;
a flange having an outer diameter larger than an outer diameter of the belt suspension portion,
the flange has a first hole forming portion that forms a part of a first hole having an inner diameter larger than an outer diameter at a bottom of a circumferentially extending annular groove formed in the shaft portion and smaller than an outer diameter of the shaft portion;
a connection hole forming portion that forms a part of the connection hole,
the connecting hole includes a second hole that communicates with the first hole and has an inner diameter larger than an outer diameter of the shaft portion;
A pulley, wherein a portion of the flange is configured to be elastically deformable so that the distance between two connection portions where the first hole forming portion and the connection hole forming portion are connected changes from a state smaller than the outer diameter of the shaft portion to a state larger than the outer diameter of the shaft portion.

According to this aspect, the connection hole includes a second hole having an inner diameter larger than the outer diameter of the shaft portion, so that the shaft portion can be passed through the connection hole. In addition, the connection hole is connected to the first hole, and a part of the flange is configured to be elastically deformable so that the distance between the two connection parts where the first hole forming part and the second hole forming part are connected can be changed from a state where it is smaller than the outer diameter of the shaft portion to a state where it is larger, so that the shaft portion passing through the connection part can be moved to the first hole. In addition, the first hole forming part forms a part of the first hole having an inner diameter larger than the outer diameter at the bottom of the annular groove extending in the circumferential direction formed in the shaft portion and smaller than the outer diameter of the shaft portion, so that the first hole forming part fits into the annular groove formed in the shaft portion. Therefore, since the flange fits into the annular groove, the flange itself is fixed to the annular groove determined in the axial direction of the shaft portion. As a result, a pulley that facilitates installation can be provided.

(Item 2) The pulley described in Item 1, wherein the flange further includes two notches sandwiching at least a portion of the first hole and the connecting hole, or at least a portion of the first hole and the connecting hole.

According to this aspect, since the flange has two notches sandwiching at least a portion of the first hole and the connecting hole, or at least a portion of the first hole and the connecting hole, the flange can elastically deform the two portions sandwiched between the first hole and the connecting hole and the two notches. This makes it easier to enlarge the first hole and the connecting hole.

(Item 3) The pulley described in Item 2, wherein the flange further includes a connecting portion that connects the two notches to either the first hole or the second hole.

In this aspect, the connecting portion connects the two notches to either the first hole or the second hole, so that the force that elastically deforms the two portions sandwiched between the first hole and the connecting hole and the two notches can be reduced.

(Item 4) The pulley described in Item 1, wherein the flange further includes a notch connecting the second hole and the outer periphery of the flange.

According to this aspect, the second hole and the outer periphery of the flange are connected by the cut, so that the flange is divided into two parts by the first hole, the second hole, and the cut. This makes it possible to reduce the force that elastically deforms the two parts of the flange that are divided by the first hole, the second hole, and the cut.

(Item 5) A pulley according to any one of items 1 to 4, in which the center of the first hole overlaps with the center of rotation of the flange.

In this way, the center of the flange and the axis of the shaft can be aligned, allowing the flange to rotate stably around the shaft.

(Item 6) A pulley according to any one of items 1 to 5, in which the flange is made of resin.

This makes it easier to manufacture the flange.

(Item 7) A pulley according to any one of Items 1 to 6,
A drive source that rotates the belt suspension portion;
a roller to which a rotational force of the belt suspension portion is transmitted and which transports the document placed on the document tray.

In accordance with this aspect, it is possible to provide a document transport device that is easy to manufacture.

(Item 8) The document transport device according to item 7,
a document reading device that optically reads the document conveyed by the document conveying device;
an image forming section that forms an image obtained by reading the document with the document reading device on a recording medium;

In accordance with this aspect, it is possible to provide an image forming device that is easy to manufacture.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

100 MFP, 100 MFP, 120 document transport device, 130 document reading section, 140 image forming section, 150 paper feeding section, 14 driving pulley, 15 driven pulley, 16 belt, 17 motor, 20C, 20M, 20Y, 20K image forming unit, 23C, 23M, 23Y, 23K photoconductor drum, 24C, 24M, 24Y, 24K developer, 26 transfer roller, 30 intermediate transfer belt, 31 timing roller, 32 fixing roller pair, 33A driving roller, 33C driven roller, 36, 36A, 36B take-out roller, 37 paper feeding roller, 41C, 41M, 41Y, 41K toner bottle, 42C, 42M, 42Y, 42K toner hopper, 51 pick roller, 52 First conveying roller, 53 Registration roller, 54 Second conveying roller, 55 Third conveying roller, 56 Discharge roller, 57 Back surface line sensor, 61 First pulley, 62 Second pulley, 63 Third pulley, 64 Fourth pulley, 65 Fifth pulley, 66 Sixth pulley, 71 First gear, 72 Second gear, 73 Third gear, 74 Fourth gear, 75 Fifth gear, 76 Sixth gear, 81 First belt, 82 Second belt, 83 Third belt, 84 Fourth belt, 85, 85A Connection hole, 86A First side portion, 86B Second side portion, 86C Connection portion, 87 First cut portion, 88 Second cut portion, 91 First hole, 92 Second hole, 93, 93A Cut portion, 94, 94A, 94B First elastic deformation portion, 95, 95A, 95B Second elastic deformation portion, 96 First connection part, 97 second connection part, 98 main body part, 99 outer edge part, 120A frame, 123 shaft part, 123A annular groove, 125 document tray, 127 document discharge tray, 159 discharge tray, 160 operation panel, 631 belt suspension part, 632 first flange, 633, 633A, 633B second flange, 641 belt suspension part, 642 first flange, 643 second flange, AR1, AR2, AR3 arrow, AX rotation axis, M motor.

Claims (8)

A belt suspension part that is rotatable around an axis of a shaft part that extends in one direction;
a flange having an outer diameter larger than an outer diameter of the belt suspension portion,
the flange has a first hole forming portion that forms a part of a first hole having an inner diameter larger than an outer diameter at a bottom of a circumferentially extending annular groove formed in the shaft portion and smaller than an outer diameter of the shaft portion;
a connection hole forming portion that forms a part of the connection hole,
the connecting hole includes a second hole that communicates with the first hole and has an inner diameter larger than an outer diameter of the shaft portion;
A pulley, wherein a portion of the flange is configured to be elastically deformable so that the distance between two connection portions where the first hole forming portion and the connection hole forming portion are connected changes from a state smaller than the outer diameter of the shaft portion to a state larger than the outer diameter of the shaft portion. The pulley of claim 1, wherein the flange further comprises two notches sandwiching at least a portion of the first hole and the connecting hole, or at least a portion of the first hole and the connecting hole. The pulley of claim 2, wherein the flange further includes a connecting portion that connects the two notches to either the first hole or the second hole. The pulley of claim 1, wherein the flange further comprises a notch connecting the second hole and the outer periphery of the flange. A pulley according to any one of claims 1 to 4, wherein the center of the first hole overlaps with the center of rotation of the flange. A pulley according to any one of claims 1 to 4, wherein the flange is made of resin. A pulley according to any one of claims 1 to 4,
A drive source that rotates the belt suspension portion;
a roller to which a rotational force of the belt suspension portion is transmitted and which transports the document placed on the document tray. The document transport device according to claim 7 ;
a document reading device that optically reads the document conveyed by the document conveying device;
an image forming section that forms an image obtained by reading the document with the document reading device on a recording medium;

Images