Transport device and image formation device

Abstract

To make the whole of a configuration that biases a shaft body by a biasing section to apply a nip pressure to a transport section compact as compared with a conventional configuration that adjusts the nip pressure by moving support means that supports the biasing section in a radial direction of the shaft body to the radial direction.SOLUTION: A transport device includes: a shaft body having a transport section for transporting a medium and extending in a first direction intersecting a transport direction of the medium; a biasing section for biasing the shaft body from an outer peripheral side of the shaft body to apply a nip pressure to the transport section; and a movable section supported independently of the shaft body and moving in the first direction to enter between the shaft body and the biasing section, thereby separating the biasing section from the shaft body.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a conveying device and an image forming apparatus. [Background technology]

[0002] The sheet conveying device described in Patent Document 1 includes a pair of conveying rollers consisting of a drive roller to which drive force is transmitted and a driven roller that is pressed by the drive roller; a pressure arm section having first and second arm sections arranged on either side of a pivot point, rotatably supporting the driven roller at the tip of the first arm section, and having first and second points of action on the second arm section that are at different distances from the pivot point; first and second biasing force applying members that apply biasing forces to the first and second points of action of the pressure arm section, respectively; and an adjustment drive section that selectively switches between changing the operating lengths of the first and second biasing force applying members, increasing the biasing force of one of the first and second biasing force applying members while decreasing the biasing force of the other of the first and second biasing force applying members, thereby adjusting the pressure force of the driven roller on the drive roller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-136808 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present disclosure is to make the entire configuration more compact in a configuration in which a shaft is biased by a biasing portion to apply nip pressure to a conveying portion, compared to a configuration in which the nip pressure is adjusted by moving a support means that supports the biasing portion in the radial direction of the shaft in the radial direction. [Means for solving the problem]

[0005] A conveying device of a first aspect of the present disclosure has a conveying section that conveys a medium, and includes a shaft that extends in a first direction that intersects the conveying direction of the medium and is supported for rotation, a biasing section that biases the shaft from the outer periphery of the shaft to apply nip pressure to the conveying section, and a movable section that is supported independently of the shaft and moves in the first direction to enter between the shaft and the biasing section and separate the biasing section from the shaft.

[0006] A conveying device of a second aspect of the present disclosure is the conveying device of the first aspect, which includes a receiving portion arranged on the outer periphery of the shaft body and which moves in accordance with movement of the movable portion from a first position where the biasing force of the biasing portion is transmitted to the shaft body to a second position shifted in the first direction from the first position where the biasing force is released.

[0007] A transport device according to a third aspect of the present disclosure is the transport device according to the second aspect, wherein the movable portion has a tapered portion that is inclined toward the receiving portion and receives the biasing force.

[0008] A fourth aspect of the conveying device of the present disclosure is a conveying device according to the third aspect, wherein the urging portion has a circular cross section, and the central portion is in contact with the receiving portion while both ends arranged on either side of the shaft in the conveying direction are supported, and the tip of the tapered portion is located closer to the shaft than the center of the central portion at the first position.

[0009] A fifth aspect of the conveying device of the present disclosure is the conveying device of the second aspect, wherein the movable part extends toward the shaft at a position away from the receiving part in the first direction and has a return part that moves the receiving part together with the movable part in the direction opposite to the first direction.

[0010] A sixth aspect of the present disclosure provides a transport device according to the fifth aspect, wherein the movable part has an operation part that is operated by an operator when moving the movable part in the first direction or the opposite direction.

[0011] An image forming apparatus according to a seventh aspect of the present disclosure includes the conveying device according to any one of the first to sixth aspects, and an image forming section that forms an image on the medium conveyed by the conveying device. [Effects of the Invention]

[0012] According to the conveying device of the first aspect of the present disclosure, in a configuration in which a shaft body is biased by a biasing portion to apply nip pressure to a conveying portion supported on the shaft body, the overall configuration is more compact than a configuration in which the nip pressure is adjusted by moving a support means supported on the shaft body and supporting the biasing portion in the radial direction of the shaft body.

[0013] According to the conveyance device of the second aspect of the present disclosure, the entire device is more compact than a configuration in which the shaft is directly biased by the biasing portion.

[0014] According to the transport device of the third aspect of the present disclosure, it is easier to switch the position where the biasing force from the biasing portion is received, compared to a configuration in which the entire biasing surface of the movable portion that receives the biasing force of the biasing portion is aligned along the first direction.

[0015] According to the conveying device of the fourth aspect of the present disclosure, it is easier for the movable part to scoop up the urging part compared to a configuration in which the tip of the tapered part is located on the opposite side of the shaft body from the center of the central part at the first position.

[0016] According to the transport device of the fifth aspect of the present disclosure, the receiving portion is moved in the direction opposite to the first direction in conjunction with the movement of the movable portion in the direction opposite to the first direction.

[0017] According to the transport device of the sixth aspect of the present disclosure, the movable part can be moved more easily in the first direction and the opposite direction than in a configuration in which the movable part is box-shaped.

[0018] According to the image forming apparatus of the seventh aspect of the present disclosure, an image is formed on the medium regardless of the thickness of the medium being conveyed. [Brief explanation of the drawings]

[0019] [Figure 1]1 is a schematic diagram illustrating the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2(A) is a plan view of a conveying device provided in the image forming apparatus according to this embodiment, and FIG. 2(B) is a side view of the conveying device. [Figure 3] FIG. 3 is a cross-sectional view of the transport section shown in FIG. 2(B) taken along line S3-S3. [Figure 4] FIG. 4(A) is a plan view of the transport device of this embodiment in a state where the operating unit abuts against the front wall of the intermediate bracket, and FIG. 4(B) is a side view of FIG. 4(A). [Figure 5] FIG. 5 is a plan view of the state shown in FIG. 4(A) with an intermediate spring removed. [Figure 6] FIG. 2 is a side cross-sectional view of the vicinity of a bearing in the conveying device according to the embodiment. [Figure 7] FIG. 7(A) is a plan view of the conveying device of this embodiment in a state where the auxiliary part is in contact with the rear wall of the intermediate bracket, and FIG. 7(B) is a side view of (A). [Figure 8] FIG. 8(A) is a plan view of a transport device according to a modified example of this embodiment, and FIG. 8(B) is a side view of (A). DETAILED DESCRIPTION OF THE INVENTION

[0020] First Embodiment An example of a conveying device and an image forming apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings. Note that arrow H in the drawings indicates the up-down direction of the image forming apparatus, arrow W indicates the width direction of the image forming apparatus, arrow DR indicates the rear side of the image forming apparatus in the front-to-rear direction, and arrow DF indicates the front side of the image forming apparatus in the front-to-rear direction. The up-down direction of the image forming apparatus, the width direction of the image forming apparatus, and the front-to-rear direction of the image forming apparatus are perpendicular to one another. These directions are defined for the sake of convenience, and the configuration of the image forming apparatus is not limited to these directions. In the descriptions of the various directions of the image forming apparatus, the term "image forming apparatus" may be omitted. The front-to-rear direction is an example of a first direction.

[0021] (Image forming device) The image forming apparatus 10 forms an image on a sheet material P. The sheet material P is an example of a medium. In the image forming apparatus 10, as shown in FIG. 1, each section is arranged inside an apparatus main body 10a. The image forming apparatus 10 mainly comprises a paper storage section 12, a main operation section 14, and a conveying section 18. The image forming apparatus 10 further comprises a display section 40 as an interface through which a user exchanges information with the image forming apparatus 10.

[0022] ((Paper storage section)) As shown in FIG. 1 , the paper storage unit 12 stores sheet materials P. The paper storage unit 12 has a first storage unit 22, a second storage unit 24, a third storage unit 26, and a fourth storage unit 28. The first storage unit 22, the second storage unit 24, the third storage unit 26, and the fourth storage unit 28 store sheet materials P of different sizes as appropriate. The first storage unit 22, the second storage unit 24, the third storage unit 26, and the fourth storage unit 28 are each provided with a feed roll 32 and a double-feed prevention roll 34. The feed roll 32 feeds out the stored sheet materials P one by one based on instructions from the management unit 20, which manages the operation of each unit. The double-feed prevention roll 34 transports the sheet materials P sent out from the feed roll 32 to a transport path 30 within the image forming apparatus 10 one by one.

[0023] ((Main operating part)) 1, the main operation unit 14 forms image data of the document digitized by the document reading unit 16 or image data received from an external device on the sheet material P conveyed from the paper storage unit 12. The main operation unit 14 has an image forming unit 60, a transfer unit 68, and a fixing device 58.

[0024] Image forming section 60 forms toner images. Image forming section 60 has image forming units 64K, 64C, 64M, and 64Y that form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. In the following description, the suffix Y, M, C, or K may be omitted unless a distinction is needed.

[0025] The image forming unit 64 includes a photosensitive drum 62, a charger 42, a developer 44, a cleaning member 46, and an exposure device 66 (66K, 66C, 66M, and 66Y). The charger 42 charges the rotating photosensitive drum 62, and the exposure device 66 irradiates the charged photosensitive drum 62 with exposure light to form an electrostatic latent image. The developer 44 then develops the electrostatic latent image to visualize it as a toner image. In other words, the image forming apparatus 10 of this embodiment is an electrophotographic device.

[0026] The transfer unit 68 transfers the toner image onto the sheet member P. As shown in FIG. 1, the transfer unit 68 is disposed below the image forming section 60. The transfer unit 68 includes a transfer belt 48, a primary transfer roll 50, a secondary transfer roll 52, an auxiliary roll 54, and a roll 56.

[0027] The transfer belt 48 is formed in an endless shape, has a triangular shape with its apex pointing downward when viewed from the front side in the front-rear direction, and contacts the image forming unit 60 from below in the up-down direction.

[0028] The primary transfer rolls 50 (50K, 50C, 50M, and 50Y) are cylindrical and extend in the front-to-rear direction. They are positioned to correspond to the photosensitive drums 62, sandwich the transfer belt 48 between them, and transfer the toner image from the photosensitive drums 62 to the transfer belt 48.

[0029] The secondary transfer roll 52 is cylindrical and extends in the front-rear direction. The secondary transfer roll 52 is disposed below the primary transfer roll 50 and transfers the toner image on the transfer belt 48 to the sheet member P at a transfer position T.

[0030] The auxiliary roll 54 has a cylindrical shape that extends in the front-rear direction, and is disposed inside the transfer belt 48, on the opposite side of the transfer belt 48 from the secondary transfer roll 52.

[0031] A plurality of rolls 56 are arranged inside the transfer belt 48, and the transfer belt 48 is wound around them. One of the rolls 56 functions as a drive roll that rotates the transfer belt 48 in the direction of arrow C in the figure.

[0032] The fixing device 58 has a cylindrical shape that extends in the front-rear direction, and is disposed downstream of the transfer position T. The fixing device 58 fixes the toner image transferred onto the sheet material P onto the sheet material P.

[0033] ((Transportation section)) 1, the conveying unit 18 receives the sheet members P conveyed from the double-feed prevention roll 34 or inserted from outside the device main body 10a and conveys them one by one. The conveying unit 18 has a conveying path 30, conveying rolls 36, and a conveying device 38.

[0034] The conveying path 30 is a path that determines the conveying direction (hereinafter simply referred to as the "conveying direction CV") of the sheet material P. Note that the conveying direction CV intersects with the front-rear direction, but does not necessarily extend along the width direction.

[0035] The upstream portion of the conveying path 30 extends from below to above on one side in the width direction. A manual feeding path 33 is connected to the upper end of the upstream portion of the conveying path 30.

[0036] The downstream portion of the conveying path 30 extends from one side to the other in the width direction and is connected to a discharge unit 80 that discharges the sheet material P to the outside of the apparatus main body 10a. A duplex conveying path 31 is connected to the downstream end of the conveying path 30, along which the sheet material P is conveyed and turned over in order to form an image on the back side of the sheet material P. The duplex conveying path 31 is equipped with a switchback path 31a, and the sheet material P sent out from the switchback path 31a is turned over and sent to the upper end of the upstream portion of the conveying path 30 in the conveying direction CV.

[0037] The transport rolls 36 are cylindrical and extend in the front-rear direction, and a plurality of transport rolls 36 are arranged along the transport path 30. The transport rolls 36 are arranged in pairs in the apparatus main body 10a so as to sandwich the transport path 30 therebetween.

[0038] The conveying device 38 is disposed upstream of the transfer position T in the conveying direction CV, temporarily stops the sheet material P, and sends out the sheet material P to the secondary transfer position at a predetermined timing. The conveying device 38 has three functions: a basic function, a nip pressure application function, and a nip pressure adjustment function. The configuration of each function of the conveying device 38 will be described below.

[0039] [Basic functions] As shown in FIGS. 2(A) and 2(B), the transport device 38 includes a guide 110, a shaft 120, and a transport roll pair 130 as components for performing basic functions.

[0040] As shown in FIGS. 2(A), 2(B), and 3, the guide 110 is a long plate-like body extending in the front-rear direction and having an L-shaped cross section, which is composed of a floor portion 113 extending in the width direction and an upright portion 114 extending upward in the vertical direction relative to the floor portion 113. The guide 110 is supported by a frame (not shown) that constitutes the device main body 10a. As shown in FIG. 2(A), the guide 110 has holes 112 in the floor portion 113 that are spaced apart from each other in the front-rear direction. In this embodiment, the guide 110 has four holes 112. The guide 110 uses the floor portion 113 to guide the sheet material P in the conveying direction CV.

[0041] As shown in Fig. 2(A), the shaft 120 is an axial body that extends in the front-rear direction and has a center C1, and is rotatably supported by the guide 110. The shaft 120 is an example of an axial body. As shown in Fig. 2(B), the shaft 120 is disposed above the guide 110.

[0042] As shown in FIGS. 2A and 2B, the transport roll pair 130 is a pair of cylinders extending in the front-rear direction and arranged in the vertical direction. The transport roll pair 130 is an example of a transport section. The transport roll pair 130 has an upper roll arranged on the upper side in the vertical direction supported by the shaft 120, and a lower roll (see FIG. 1) arranged on the lower side in the vertical direction supported by the guide 110. The transport roll pair 130 is arranged at a position corresponding to the hole 112. The transport roll pair 130 transports the sheet material P in the transport direction CV with a portion of the cylindrical surface of the upper roll exposed from the hole 112 below the lower surface 110A of the guide 110 and pressed against the lower roll by a nip pressure applying function. In this embodiment, four pairs of transport rolls 130 are arranged corresponding to the four holes 112.

[0043] [Application of nip pressure] The conveying device 30 includes a bearing 180, an end-side spring 190, an intermediate spring 140, an end-side bracket 192, and an intermediate bracket 190 as components for exerting a nip pressure application function. The end-side spring 190 and the intermediate spring 140 apply nip pressure to the conveying roll pair 130 via the shaft 120.

[0044] As shown in FIG. 5, bearing 180 is disposed on the outer periphery of shaft 120 and has a circular shape when viewed from the front in the front-rear direction. Bearing 180 is an example of a receiving portion. In this embodiment, bearing 180 is a rolling bearing. Bearing 180 reduces rotational resistance in a portion where a relatively strong nip pressure is applied. The length (thickness) of bearing 180 in the front-rear direction is designated TB (see FIG. 6).

[0045] As shown in Figures 2(A) and 2(B), the end-side springs 190 are disposed on both end sides in the front-rear direction, and in this embodiment, the end-side springs 190 are tension coil springs. As shown in Figure 2(B), the end-side springs 190 are disposed in a state in which a central portion 190C is bent in a U-shape so as to cover the upper and lower sides of the shaft 120, and one end 190A and the other end 190B are positioned on either side of the shaft 120 in the conveying direction CV. The end-side springs 190 bias the shaft 120 from the outer periphery while being supported by end-side brackets 192, as will be described later.

[0046] As shown in FIG. 3, the intermediate spring 140 is bent in a U-shape so that the central portion 140C covers the upper and lower sides of the shaft 120, and biases the shaft 120 from the outer periphery so that one end 140A and the other end 140B are positioned to the sides of the shaft 120.

[0047] 2(A) and 2(B), the intermediate spring 140 is disposed at a position intermediate the pair of end-side springs 190 in the front-rear direction, where no hole 112 is formed, and in this embodiment, the intermediate spring 140 is a tension coil spring. The intermediate spring 140 is an example of a biasing portion.

[0048] 6, the intermediate spring 140 is circular in shape with its center at CS and its radius to its outer periphery at RS in a cross section of the central portion 140C taken along the center C1 of the shaft 120. Twice the radius RS of the intermediate spring 140 (i.e., the diameter of the intermediate spring 140) is longer than the length TB of the bearing 180 in the front-to-rear direction.

[0049] The intermediate spring 140 has a larger elastic modulus than the end spring 190. The intermediate spring 140 biases the shaft 120 more strongly than the end spring 190. The intermediate spring 140 biases the shaft 120 via the bearing 180 while being supported by the intermediate bracket 190 as described below.

[0050] 2(A) and 2(B), the end bracket 192 has a plate-shaped main body 194 that conforms to the guide 110, and a pair of side walls 196 that rise from both ends of the main body 194 in the width direction, and has a U-shape that opens upward when viewed from the front to back direction. The end bracket 192 is fixed to the guide 110. The pair of side walls 196 each have a hook 196A on the front or rear side in the front to back direction.

[0051] The end-side brackets 192 are disposed on both end sides of the shaft 120, specifically between the two pairs of transport roll pairs 130 on the front-rear side and between the two pairs of transport roll pairs 130 on the rear side in the front-rear direction, and are fixedly supported on the upper and lower sides of the shaft 120. The hooks 196A support both end ends of the end-side spring 190 in a state in which the end-side bracket 192 is pressed against the shaft 120 from above in the vertical direction. In other words, the end-side spring 190 urges the shaft 120 by the center portion 190C in a state in which it is supported by the end-side bracket 192.

[0052] As shown in Figures 2(A) and 2(B), the intermediate bracket 150 has a front wall 151, a rear wall 152, a side wall 153, and a folding portion 154, and is located at the midpoint between the pair of end-side brackets 192 in the front-to-rear direction, and is positioned between the shaft 120 and the guide 110 in the up-down direction.

[0053] The front wall 151 is a wall that stands upward on the front side in the front-rear direction, as shown in Fig. 3. The front walls 151 are formed as a pair, spaced apart in the width direction, with the shaft 120 sandwiched between them.

[0054] 4(A) and 4(B), the rear wall 152 is a wall that stands upward on the rear side in the front-to-rear direction. The rear walls 152 are formed as a pair, spaced apart in the width direction, with the shaft 120 at the center.

[0055] As shown in FIGS. 4A and 4B, the side walls 153 are a pair of walls extending in the front-rear direction and standing upright in the up-down direction, spaced apart from each other in the width direction and sandwiching the shaft 120 therebetween. The side walls 153 are formed higher than the front wall 151 and the rear wall 152. The side walls 153 each have a hook 153A at the front end in the front-rear direction. The hook 153A supports both ends of the intermediate spring 140 at position P0 in the front-rear direction. In other words, the intermediate spring 140 biases the shaft 120 via the center portion 140C while supported by the side walls 153. Note that position P0 is the absolute position of the guide 110 and the intermediate bracket 150 in the device main body 10a. In other words, the guide 110 and the intermediate bracket 150 are fixed to the device main body 10a.

[0056] As shown in FIGS. 4(A) and 4(B), the bent portion 154 is a protrusion formed by bending the front end of the side wall 153 toward the shaft 120 in the upward and downward direction of the hook 153A. The bent portion 154 is disposed on the rear side of the intermediate spring 140 in the forward and backward direction, closer to both ends in the conveying direction CV than the center portion 140C of the intermediate spring 140. The bent portion 154 prevents deformation of the intermediate spring 140 toward the rear side in the forward and backward direction. As shown in FIG. 3, the bent portion 154 is disposed above the center of the shaft 120 in the upward and downward direction.

[0057] With the above configuration, a nip pressure is applied to the pair of transport rolls 130.

[0058] [Nip pressure adjustment] The conveying device 30 is provided with a nip pressure adjustment mechanism 100 as a configuration for performing a nip pressure adjustment function. The nip pressure adjustment mechanism 100 is configured with a structure for supporting a bearing 180 slidably on a shaft 120 and a structure for providing a movable part 160 slidably on a shaft 112.

[0059] The bearing 180 is slidable (reciprocating) in the front-to-rear direction on the outer periphery of the shaft 120 to adjust the nip pressure. Specifically, the inner diameter of an inner ring constituting the bearing 180 is slightly smaller than the outer diameter of the shaft 120, and the shaft 120 is inserted into this inner ring, thereby allowing the bearing 180 to slide relative to the shaft 120. As shown in FIG. 5, the position of the bearing 180 in the front-to-rear direction of the shaft 120 is indicated by position P1. In other words, position P1 indicates the reference position of the bearing 180 relative to the shaft 120. Position P1 is an example of a first position.

[0060] Here, adjustment refers to switching between a state in which intermediate spring 140 is applied to shaft 120 and a state in which it is not applied to shaft 120. The adjustment of nip pressure is automatically determined by the positional relationship between bearing 180's positions P1 and P0.

[0061] As shown in Figures 2(A) and 2(B), the movable part 160 is formed in an arch shape with concaves and convexes on its outer surface, and is supported independently of the shaft 120. Specifically, the movable part 160 extends in the front-rear direction, and is supported by the intermediate bracket 150 so as to be slidable in the front-rear direction, with the shaft 120 passing through two arch-shaped openings that sandwich the bearing 180 in the front-rear direction. More specifically, as shown in Figure 6, the movable part 160 is supported on the intermediate bracket 150 so as to be slidable in the front-rear direction, while being spaced radially from the outer periphery of the shaft 120, and its movement in the up-down direction is restricted. The movable part 160 has a main body 162, an operating part 176, an auxiliary part 178, and a return part 170.

[0062] As shown in Figures 3, 4(A), 4(B), and 6, the main body 162 is formed in an arch shape on the front side in the front-rear direction. An opening is formed inside the main body 162 through which the shaft 120 can pass (see Figure 6). The main body 162 is supported by the intermediate bracket 150 via a guide means (not shown), and is slidable in the front-rear direction on the intermediate bracket 150 while its movement in the up-down direction is restricted. The main body 162 is disposed forward of the intermediate spring 140 in the front-rear direction. When the movable part 160 moves rearward in the front-rear direction, a tapered portion 166 (described later) enters between the shaft 120 and the intermediate spring 140, separating the intermediate spring 140 from the shaft 120 (details will be described later).

[0063] As shown in FIGS. 4B and 6 , the tapered portion 166 is formed on the upper surface of the main body 162 and slopes from the front to the rear in the front-to-rear direction. The tapered portion 166 is a part of the main body 162. The tip end EG of the tapered portion 166 is located closer to the shaft 120 than the center CS of the intermediate spring 140. Here, the tip end EG refers to the end point of the curved front end of the rear end surface 166A of the main body 162 in the front-to-rear direction, when the rear end surface 166A is curved in the front-to-rear direction. The length of the tapered portion 166 in the front-to-rear direction is longer than the diameter of the intermediate spring 140 (twice the radius RS). When the intermediate spring 140 is positioned on the tapered portion 166, i.e., when the position P1 of the bearing 180 is deviated from the position P0, the intermediate spring 140 receives a biasing force from the intermediate spring 140.

[0064] As shown in Figures 4(A) and 4(B), the operating portion 176 is located at the front end of the main body 162 in the front-rear direction, and is formed in a flange shape that protrudes in the up-down and width directions beyond the main body 162, and is a plate-like member that extends along the up-down and width directions. The operating portion 176 is a portion that is operated by an operator (not shown) when moving the movable portion 160 in the front-rear direction. The tapered portion 166 extends up to the operating portion 176. The movable portion 160 is movable forward in the front-rear direction until it hits the front wall 151 of the intermediate bracket 150.

[0065] The auxiliary part 178 is formed in an arch shape and, as shown in FIG. 6 , is disposed at a position where the intermediate spring 140 is sandwiched between the auxiliary part 178 and the main body 162 in the front-rear direction and spaced a distance DM from the main body 162 while the biasing force of the intermediate spring 140 is in effect. An opening through which the shaft 120 can pass is formed inside the auxiliary part 178. As shown in FIGS. 7(A) and 7(B), the auxiliary part 178 has a stopper function in which a protrusion 178A formed at its rear end in the front-rear direction hits the rear wall 152 of the intermediate bracket 150, thereby stopping the movement of the movable part 160 in the front-rear direction. The distance DM between the auxiliary part 178 and the main body 162 is longer than twice the radius RS of the intermediate spring 140 (i.e., the diameter of the intermediate spring 140).

[0066] 5, the return portion 170 is disposed between the main body 162 and the auxiliary portion 178, and connects the main body 162 and the auxiliary portion 178. In this embodiment, the return portion 170, the main body 162, and the auxiliary portion 178 are integrally formed.

[0067] Furthermore, the return portion 170 is formed so as to be recessed in the width direction toward the shaft 120. Specifically, the return portion 170 has a shape in which both ends in the front-rear direction extend further toward the shaft 120 than the center portion in the front-rear direction, and the bearing 180 is sandwiched between the both ends. That is, the return portion 170 of the movable portion 160 moves the bearing 180 in the front-rear direction as it moves in the front-rear direction. Specifically, when the bearing 180 comes into contact with the rear end portion of the return portion 170 in the front-rear direction, the bearing 180 is moved forward in the front-rear direction, and when the bearing comes into contact with the front end portion of the return portion 170 in the front-rear direction, the bearing 180 is moved backward in the front-rear direction.

[0068] As described above, the nip pressure on the transport roll pair 130 is adjusted by the nip pressure adjusting mechanism 100 in accordance with the position of the movable part 160, that is, the bearing 180.

[0069] Then, the image forming apparatus 10 forms a toner image formed by the main operation unit 14 on the sheet material P transported from the paper storage unit 12 via the transport unit 18.

[0070] <Action and effect> The operation of the conveying device 38 of this embodiment will be described. As shown in Figures 4(A) and 4(B), when position P1 coincides with position P0, the bearing 180 receives a biasing force from the intermediate spring 140 on its outer circumferential surface. When the bearing 180 receives the biasing force, nip pressure is generated in the conveying roll pair 130 via the shaft 120. At this time, because the intermediate spring 140 has a larger elastic modulus than the end-side spring 190, the nip pressure is greater than when nip pressure is applied to the conveying roll pair 130 by only the end-side spring 190.

[0071] Next, a description will be given of adjusting the nip pressure. To change the nip pressure, the operator grasps the operating portion 176 of the movable portion 160 and moves the movable portion 160 together with the bearing 180 rearward in the front-to-rear direction. As shown in FIGS. 7(A) and 7(B), when position P1 deviates from position P0, that is, when position P1 is located rearward of position P0 in the front-to-rear direction, the bearing 180 is released from the biasing force of the intermediate spring 140, and the movable portion 160, more specifically, the tapered portion 166, receives the biasing force. When position P1 deviates from position P0, the intermediate spring 140 moves toward the operating portion 176 along the tapered portion 166 of the movable portion 160. When the auxiliary portion 178 abuts against the intermediate bracket 150, the movable portion 160 stops moving in the front-to-rear direction.

[0072] The conveying device 38 of this embodiment has a conveying roll pair 130 that conveys the sheet material P, and includes a shaft 120 that extends in a front-to-rear direction intersecting the conveying direction CV and is rotatably supported, an intermediate spring 140 that biases the shaft 120 from the outer periphery to apply nip pressure to the conveying roll pair 130, and a movable part 160 that is supported independently of the shaft 120 and moves in the front-to-rear direction to enter between the shaft 120 and the intermediate spring 140 and separate the intermediate spring 140 from the shaft 120. According to this configuration, in a configuration in which the intermediate spring 140 biases the shaft 120 to apply nip pressure to the conveying roll pair 130 supported by the shaft 120, the entire configuration is more compact than a configuration in which the nip pressure is adjusted by radially moving a support means that is supported by the shaft 120 and supports the intermediate spring 140 in the radial direction of the shaft 120.

[0073] Furthermore, conveying device 38 of this embodiment includes bearing 180, which is disposed on the outer periphery of shaft 120 and moves with movement of movable part 160 from position P1, where the biasing force of intermediate spring 140 is transmitted to shaft 120, to position P0, which is shifted forward or backward from position P1 and where the biasing force is released. According to this configuration, bearing 180 has an outer diameter larger than the outer diameter of shaft 120. Therefore, compared to a configuration in which shaft 120 is directly biased by intermediate spring 140, the overall device can be made more compact by reducing the biasing amount of intermediate spring 140 by the difference between the outer diameter of bearing 180 and the outer diameter of shaft 120.

[0074] Furthermore, in the transport device 38 of this embodiment, the movable part 160 has a tapered part 166 that is inclined toward the bearing 180 and receives the biasing force. With this configuration, it is easier to switch the position at which the biasing force from the intermediate spring 140 is received, compared to a configuration in which the entire biasing surface of the movable part 160 that receives the biasing force of the intermediate spring 140 is aligned in the front-to-rear direction.

[0075] Furthermore, in the conveying device 38 of this embodiment, the intermediate spring 140 has a circular cross section, and the central portion 140C is in contact with the bearing 180 while being supported at both end portions 140A and 140B disposed on either side of the shaft 120 in the conveying direction CV, and the tip end EG of the tapered portion 166 is positioned closer to the shaft 120 than the center CS of the central portion 140C at position P1. With this configuration, it is easier for the movable portion 160 to scoop up the intermediate spring 140 compared to a configuration in which the tip end EG of the tapered portion 166 is positioned on the opposite side to the shaft 120 with respect to the center CS of the central portion 140C at position P1.

[0076] Furthermore, in the transport device 38 of this embodiment, the movable part 160 has a return part 170 that extends toward the shaft 120 at a position spaced apart from the bearing 180 in the front-rear direction and moves the bearing 180 in the front-rear direction together with the movable part 160. According to this configuration, the bearing 180 moves rearward in the front-rear direction as the movable part 160 moves rearward in the front-rear direction.

[0077] Furthermore, in the transport device 38 of this embodiment, the movable part 160 has an operation part 176 that is operated by an operator when moving the movable part 160 in the front-rear direction. With this configuration, the movable part 160 can be moved in the front-rear direction more easily than in a configuration in which the movable part 160 is box-shaped.

[0078] The image forming apparatus 10 of this embodiment includes a conveying unit 18 having the above-described conveying device 38, and a main operation unit 14 that forms an image on the sheet material P conveyed by the conveying unit 18. According to this configuration, an image is formed on the sheet material P regardless of the thickness of the sheet material P being conveyed.

[0079] <Modification> Although the present disclosure has been described in detail with respect to specific embodiments, it will be apparent to those skilled in the art that the present disclosure is not limited to such embodiments and that the present disclosure can take on various other embodiments within the scope of the present disclosure.

[0080] Although the image forming apparatus 10 has been described as an electrophotographic apparatus, the image forming apparatus 10 is not limited to this and may be an inkjet apparatus.

[0081] Although the intermediate spring 140 is supported by the intermediate bracket 150 in the above embodiment, the present invention is not limited to this. The intermediate spring 140 may be supported by the device main body 10a via the intermediate bracket 150, or may be supported directly by the device main body 10a. The intermediate spring 140 may also be a compression coil spring or a leaf spring.

[0082] The conveying device 38 in the above embodiment is provided with a bearing 180 that is disposed on the outer periphery of the shaft 120 and moves as the movable part 160 moves from position P1, where the biasing force of the intermediate spring 140 is transmitted to the shaft 120, to position P0, which is shifted forward and backward from position P1 and where the biasing force is released, but this is not essential. The bearing 180 may be a sliding bearing, or the intermediate spring 140 may directly bias the shaft 120 without providing a bearing 180.

[0083] In the above embodiment, the movable part 160 has a tapered part 166 formed on its upper surface, but this is not limited to this. For example, as shown in FIG. 8, a flat part 266 that is flat along the front-rear direction may be formed on the upper surface of the movable part 260. In this case, when an operator (not shown) operates the operation part 276, the biasing force that the flat part 266 receives from the intermediate spring 140 is constant, making operation in the front-rear direction easier, except for the fact that the flat part 266 moves in an arc starting from both ends of the intermediate spring 140. Furthermore, both a tapered part and a flat part may be formed on the upper surface of the movable part. Note that the configuration other than the movable part 260 is the same as the basic configuration of the above embodiment.

[0084] In the conveying device 38 of the above embodiment, the intermediate spring 140 has a circular cross section, and the central portion 140C is in contact with the bearing 180 while both end portions 140A and 140B, which are arranged on either side of the shaft 120 in the conveying direction CV, are supported, and the tip end EG of the tapered portion 166 is located on the shaft 120 side with respect to the center CS of the central portion 140C at position P1, but this is not essential. The intermediate spring 140 may have a rectangular cross section as long as it biases the bearing 180 and the movable portion 160.

[0085] In the transport device 38 of the above embodiment, the movable part 160 includes the return part 170, which extends toward the shaft 120 at a position spaced apart from the bearing 180 in the front-rear direction and moves the bearing 180 forward in the front-rear direction together with the movable part 160, but this is not essential. For example, the movable part 160 and the return part 170 may be configured as separate parts.

[0086] In the transport device 38 of the above embodiment, the movable unit 160 has the operation unit 176 that is operated by an operator when moving the movable unit 160 in the forward and backward directions, but this is not limited to this. For example, the movable unit 160 and the operation unit 176 may be configured as separate parts.

[0087] The image forming apparatus 10 of the above embodiment includes the conveying section 18 having the conveying device 38, and the main operation section 14 that forms an image on the sheet material P conveyed by the conveying section 18, but is not limited to this. The image forming apparatus 10 may be applied to an apparatus configured with a paper feeder and a conveying device, or an apparatus configured with a post-processing device such as bookbinding or folding, and a conveying device.

[0088] <Additional Notes> (((1))) a shaft body having a transport section that transports a medium, extending in a first direction intersecting a transport direction of the medium, and supported for rotation; a biasing section that biases the shaft from an outer circumferential side of the shaft to apply nip pressure to the conveying section; a movable portion that is supported independently of the shaft body and moves in the first direction to enter between the shaft body and the biasing portion and separate the biasing portion from the shaft body; A conveying device comprising: (((2))) The conveying device described in (((1))) includes a receiving portion that is arranged on the outer periphery of the shaft body and moves in accordance with movement of the movable portion from a first position where the biasing force of the biasing portion is transmitted to the shaft body, to a second position shifted in the first direction from the first position where the biasing force is released. (((3))) The conveying device according to (((2))), wherein the movable portion has a tapered portion that is inclined toward the receiving portion and receives the biasing force. (((4))) the biasing portion has a circular cross section, and a central portion thereof is in contact with the receiving portion while both end portions thereof, which are disposed on either side of the shaft body in the conveying direction, are supported; The conveying device according to (((3))), wherein the tip of the tapered portion is located closer to the shaft body than the center of the central portion at the first position. (((5))) The conveying device described in any one of (((2))) to (((4))), wherein the movable part extends toward the shaft body at a position away from the receiving part in the first direction and has a return part that moves the receiving part together with the movable part in a direction opposite to the first direction. (((6))) The conveying device according to any one of (((2))) to (((5))), wherein the movable part has an operating part that is operated by an operator when moving in the first direction or the opposite direction. (((7))) A conveying device according to any one of (((1))) to (((6))), an image forming unit that forms an image on the medium transported by the transport device; An image forming apparatus comprising: According to the conveying device of (((1))), in a configuration in which the shaft is biased by a biasing section to apply nip pressure to the conveying section, the overall configuration is more compact than a configuration in which the nip pressure is adjusted by moving a support means that supports the biasing section in the radial direction of the shaft. According to the conveying device of (((2))), the entire device can be made more compact than a configuration in which the shaft is directly biased by the biasing portion. According to the conveying device (((3))), the position where the biasing force is received from the biasing portion can be easily switched compared to a configuration in which the entire biasing surface of the movable portion that receives the biasing force of the biasing portion is aligned along the first direction. According to the conveying device (((4))), it is easier for the movable part to scoop up the urging part compared to a configuration in which the tip of the tapered part is located on the opposite side of the shaft body from the center of the central part at the first position. According to the conveying device of (((5))), the receiving portion is moved in the direction opposite to the first direction as the movable portion is moved in the direction opposite to the first direction. According to the conveying device of (((6))), the movable part can be moved more easily in the first direction and the opposite direction than in a configuration in which the movable part is box-shaped. According to the image forming apparatus (((7))), an image is formed on the medium regardless of the thickness of the medium being conveyed. [Explanation of symbols]

[0089] 10 Image forming device 10a Device body 12 Paper storage section 14 Main operating part 16 Document reading unit 18 Conveyor 30 Transport Route 36 Transport roll 38 Conveyor equipment 60 Image forming unit 100 Nip pressure adjustment mechanism 110 Guide 120 shaft 130 Transport Roll Pair 150 Intermediate bracket 160, 260 moving parts 162 Main Unit 166 Tapered section 176, 276 Operation section 178 Auxiliary Department 180 bearing 192 End bracket 266 Flat area EG tip P sheet material T transcription position

Claims

1. a shaft body that has a transport section that transports a medium, extends in a first direction that intersects with a transport direction of the medium, and is rotatably supported; a biasing section that biases the shaft from an outer circumferential side of the shaft to apply nip pressure to the conveying section; a movable portion that is supported independently of the shaft body and moves in the first direction to enter between the shaft body and the biasing portion and separate the biasing portion from the shaft body; A conveying device comprising:

2. 2. The conveying device according to claim 1, further comprising a receiving portion that is disposed on the outer periphery of the shaft body and moves in accordance with movement of the movable portion from a first position where the biasing force of the biasing portion is transmitted to the shaft body to a second position where the biasing force is released at a position shifted in the first direction from the first position.

3. The transport device according to claim 2 , wherein the movable portion has a tapered portion that is inclined toward the receiving portion and receives the biasing force.

4. the biasing portion has a circular cross section, and a central portion thereof is in contact with the receiving portion while both end portions thereof, which are disposed on either side of the shaft body in the conveying direction, are supported; The conveying device according to claim 3 , wherein the tip of the tapered portion is located closer to the shaft than the center of the central portion at the first position.

5. The conveying device according to claim 2 , wherein the movable portion has a return portion that extends toward the shaft body at a position spaced apart from the receiving portion in the first direction and moves the receiving portion together with the movable portion in a direction opposite to the first direction.

6. The transport device according to claim 5 , wherein the movable portion has an operating portion that is operated by an operator when moving the movable portion in the first direction or the opposite direction.

7. A conveying device according to any one of claims 1 to 6; an image forming unit that forms an image on the medium transported by the transport device; An image forming apparatus comprising:

Images