JP2006044938A - Roller mechanism and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller mechanism capable of preventing the generation of noise when paper pass through. <P>SOLUTION: This roller mechanism is provided with a roller unit structured of a driving roller 101 and a driven roller 102 opposite to the driving roller and an energizing member 105 fixed to abut on a shaft body 103 of the driven roller 102 in the crossing condition and for energizing the driven roller 102 with the shaft body 103 toward the driving roller 101. The energizing member 105 is provided with a presser surface part 1051 structured to apply energizing force to the shaft body 103 in a direction (a direction expressed with an arrow H) eccentric in relation to the center direction (a direction expressed with an arrow T) from the shaft body 103 to a nip part 110 between the driven roller 102 and the driving roller 101 in the energizing condition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly to an image forming apparatus including a roller mechanism including a driving roller and a driven roller facing the driving roller.

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine has a conveyance path that conveys a sheet (sheet) to be printed (printed) in an electrophotographic process step, and a driving roller and a driving roller are provided at predetermined positions on the conveyance path. A roller unit (for example, a pair of discharge rollers) composed of opposed driven rollers is provided. Such a roller unit generally has a coiled spring 400 (cylindrical tension spring) as shown in FIG. The urging member shown in the disclosed “spring” (a nip is formed between the rollers by being pressed using an elastic member, and the conveyed paper passes through the nip portion of the roller unit. Thus, the sheet is conveyed downstream.
JP-A-6-135590

  By the way, a predetermined nip amount is secured between the outer diameter of the shaft body (metal shaft) penetrating the driven roller and the bearing hole portion of the bearing body (sheet metal portion) receiving the shaft body with respect to the driving roller. A clearance (gap: tolerance) necessary for smoothly sliding the driven roller is set. In other words, the driven roller is pressed against the driving roller by the biasing member so that the driven roller can be moved by the clearance. The body vibrates and a sound (vibration noise; abnormal noise) may be generated between the bearing body and the body.

  The present invention has been made in view of the above circumstances, and in a case where the driven roller is urged with a clearance so that a predetermined nip amount is ensured with respect to the driving roller, the paper passage can be performed with a simpler configuration. It is an object of the present invention to provide a roller mechanism capable of preventing the generation of sound accompanying time and the like and an image forming apparatus using the roller mechanism.

  A roller mechanism according to claim 1 of the present invention is fixed so as to abut on a roller unit composed of a driving roller and a driven roller facing the driving roller in a state of intersecting with the shaft of the driven roller. And a biasing member that biases the driven roller toward the driving roller, wherein the biasing member is directed from the shaft body to the nip portion between the driven roller and the driving roller in the biased state. And a pressing surface portion configured to apply an urging force in a direction eccentric to the central direction to the shaft body.

  According to the above configuration, the pressing surface portion of the urging member is held by the urging member fixed so as to come into contact with the shaft of the driven roller in the roller unit including the driving roller and the driven roller facing the driving roller. As a result, a biasing force is applied to the shaft body in a direction eccentric with respect to the central direction from the shaft body toward the nip portion between the driven roller and the drive roller. Thus, in a simpler configuration using an urging member having a pressing surface portion, for example, a predetermined nip amount of the roller unit is applied by applying an urging force to the shaft body in a direction eccentric from the center direction. In such a state that the shaft body of the driven roller supported by a certain support member with a clearance is always pressed against one side (peripheral edge portion) of the support portion (for example, the notch groove portion) of the support member. Thus, it is possible to prevent the generation of sound (abnormal noise) due to the vibration of the shaft through the driven roller when the sheet passes through the nip portion.

  A roller mechanism according to a second aspect of the present invention is the roller mechanism according to the first aspect, further comprising a support member that has a predetermined notch groove portion and supports the shaft body in a state of loosely fitting in the notch groove portion. The shaft body is brought into contact with one end edge of the notch groove portion or the one end edge and the bottom end edge by the biasing force in the eccentric direction. According to this, the shaft body of the driven roller is supported in a state where it is loosely fitted in the notch groove portion of the support member, and this shaft body is one side edge of the notch groove portion by the biasing force in the eccentric direction by the biasing member. Alternatively, the driven roller and the shaft body vibrate when the sheet passes through the nip portion, and the shaft body thus vibrated is notched. It is possible to prevent the sound from being generated by abutting the peripheral edge of (clearance).

  A roller mechanism according to a third aspect is the roller mechanism according to the first or second aspect, wherein the pressing surface portion of the urging member includes a small diameter portion on one end side, a large diameter portion on the other end side, and the small diameter portion on the urging member. It is comprised from the taper part over a large diameter part, It is characterized by the above-mentioned. According to this, the biasing force (pressing surface portion) is provided with a taper portion to apply an urging force to the shaft body in an eccentric direction with respect to the central direction from the shaft body toward the nip portion. This can be easily performed by a simple configuration of urging while abutting against the shaft body.

  A roller mechanism according to a fourth aspect is the roller mechanism according to the first or second aspect, wherein the pressing surface portion of the urging member is gradually changed from a small diameter to a large diameter from one end side to the other end side of the urging member. It is characterized by being. According to this, the pressing surface portion of the urging member can be formed, for example, in a tapered shape with a simple configuration of gradually changing from a small diameter to a large diameter, and in the center direction from the shaft body toward the nip portion. On the other hand, it is possible to easily apply an urging force in an eccentric direction to the shaft body with a simple configuration in which the gradual change, for example, a tapered pressing surface portion is brought into contact with the shaft body and urged. become.

  A roller mechanism according to a fifth aspect is the roller mechanism according to the third or fourth aspect, wherein the biasing member is a tension spring formed in a coil shape. According to this, the urging member can be realized with a simpler configuration as a tension spring formed in a coil shape.

  An image forming apparatus according to a sixth aspect includes the roller mechanism according to any one of the first to fifth aspects.

  According to the above configuration, in the roller mechanism provided in the apparatus, the shaft body of the driven roller that is supported by the support member having a clearance so as to secure a predetermined nip amount of the roller unit is provided with the biasing member. Equipped with a tapered portion (portion that is gradually changed from a small diameter to a large diameter) and biased while abutting it against the shaft body, it is eccentric with respect to the central direction toward the nip portion. The urging force is applied in the selected direction so that the shaft is always pressed against one side (one side) of the support part (notch groove) of the support member. Thus, it is possible to provide an image forming apparatus including a roller mechanism in which generation of sound (abnormal noise) due to vibration of a shaft through a driven roller accompanying the above is prevented.

  According to the invention of claim 1, in a simpler configuration using an urging member having a pressing surface portion, by applying an urging force in a direction eccentric from the center direction to the shaft body, for example, The shaft of the driven roller supported by a certain support member with a clearance to secure a predetermined nip amount of the roller unit is connected to one side (periphery portion of the support portion (for example, a notch groove portion) of the support member. ) In a state where it is always pressed, and generation of noise (abnormal noise) due to vibration of the shaft through the driven roller when the sheet passes through the nip portion can be prevented.

  According to the second aspect of the present invention, the shaft body of the driven roller is supported in a state of loosely fitting in the notch groove portion of the support member, and the shaft body is notched by the biasing force in the eccentric direction by the biasing member. The one side edge, that is, one side edge or the one side edge and the bottom edge, so that the driven roller and the shaft body vibrate when the paper passes through the nip portion. Further, it is possible to prevent the sound from being generated by the vibration of the shaft body coming into contact with the peripheral edge of the notch groove (clearance).

  According to the third aspect of the present invention, the biasing force (pressing surface portion) is applied to the biasing member in the direction eccentric to the central direction from the shaft body toward the nip portion. This can be easily performed by a simple configuration in which the portion is urged while being in contact with the shaft body.

  According to the fourth aspect of the present invention, the pressing surface portion of the urging member can be formed, for example, in a tapered shape with a simple configuration of gradually changing from a small diameter to a large diameter, and from the shaft body toward the nip portion. A simple configuration in which an urging force in a direction eccentric with respect to the central direction is applied to the shaft body, and the urging force is applied by, for example, bringing the tapered pressing surface portion into contact with the shaft body. Can be easily done.

  According to the fifth aspect of the present invention, the urging member can be realized with a simpler configuration that is a tension spring formed in a coil shape.

  According to the sixth aspect of the present invention, in the roller mechanism provided in the apparatus, the shaft body of the driven roller supported by a certain supporting member having a clearance so as to ensure a predetermined nip amount of the roller unit. The urging member has a taper portion (a portion gradually changed from a small diameter to a large diameter) and is urged while being abutted against the shaft body, so that the central direction toward the nip portion is achieved. By applying an urging force in a direction that is eccentric to the shaft, it is possible to always press the shaft body against one side (peripheral edge portion) of the support portion (notch groove portion) of the support member, and the paper passes through the nip portion. It is possible to provide an image forming apparatus including a driven roller that is accompanied by time and the like, and a roller mechanism that prevents generation of sound (abnormal noise) due to vibration of the shaft body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a printer showing an example of an image forming apparatus to which a roller mechanism according to the present invention is applied. As shown in FIG. 1, the printer 1 includes a developing device 2 for each color of cyan (C), magenta (M), yellow (Y), and black (K) in the printer body. Each developing device 2 is provided with a photosensitive drum 3 made of a-Si (amorphous silicon) or the like, and rotates in the direction of the arrow in the figure. The photosensitive drum 3 is uniformly charged by the charging unit 4, and the LED light is exposed from the exposure unit 5 based on image data transmitted from an external device or the like connected to the printer 1 via a predetermined network. Irradiation on the surface of the body drum 3 forms an electrostatic latent image. Then, toner adheres to the electrostatic latent image to form a toner image on the surface of the photosensitive drum 3. The toner is supplied from the toner supply containers 7C, 7M, 7Y and 7B, respectively. A photosensitive drum 3 is provided for each toner color, and a paper transport belt 8 is provided below the photosensitive drum 3. The sheet conveying belt 8 is pressed against each photosensitive drum 3 by the transfer roller 9 and is rotated according to a driving roller 10 that is rotationally driven by a motor (not shown) and a sheet conveying belt 8 that is rotated endlessly by the driving roller 10. The driven roller 11 is rotated in the direction opposite to the rotation direction of the photosensitive drum 3. Each photosensitive drum 3 is provided with a cleaning mechanism 6 for removing residual toner and the like on the photosensitive drum 3. An adsorption roller 12 for electrostatically adsorbing the sheet to the sheet conveying belt 8 is provided at a position facing the driven roller 11, for example, on the most upstream side of the sheet conveying belt 8.

  On the other hand, the sheet is conveyed from the sheet feeding mechanism 13 to the sheet conveying belt 8 via the sheet conveying path 14, and the sheet feeding operation for the image transfer operation by the photosensitive drums 3 and the transfer rollers 9 is performed by the registration rollers 15. Timing is adjusted. After this timing adjustment, the registration roller 15 is driven to rotate, and the sheet is conveyed between the photosensitive drum 3 and the sheet conveying belt 8. While the sheet is conveyed between the photosensitive drum 3 and the sheet conveying belt 8, the toner images of the respective colors on the surface of the photosensitive drums 3 are sequentially transferred onto the sheet. The sheet on which the toner image has been transferred by all the photosensitive drums 3 is conveyed to the fixing roller pair 16 and the toner image is fixed to form a color image. The fixing roller pair 16 includes a heat roller 161 with a built-in heater, and a pressure roller 162 provided in pressure contact with the heat roller 161. By passing the paper between the rollers, the paper is passed. Heat and press to fix the toner image on the paper.

  The sheet that has passed through the fixing roller pair 16 is sent to the sheet conveyance path 17 and discharged to the discharge tray 19 by the discharge roller pair 18 or discharged to the discharge tray 21 by the discharge roller pair 20. Switching of the discharge destination to the discharge tray 19 or the discharge tray 21 is performed by the branching claw 22. However, the switching of the discharge destination is performed according to an operation instruction from the operation unit (not shown) of the printer 1 or the external device. In the printer 1, when discharging the paper to the discharge tray 21, the print surface is discharged in a so-called face-up state where the print surface is face up, and when discharging to the discharge tray 19, the print surface is face down. It is discharged in a so-called face-down state.

  By the way, the paper conveyance path of the printer 1, for example, the paper conveyance path 17, is composed of a roller unit including a driving roller 101 and a driven roller 102 disposed opposite to the driving roller 101, and has been conveyed from upstream. A roller mechanism 100 is provided that passes the paper through the nip portion 110 between the driving roller 101 and the driven roller 102 and conveys the paper to the downstream. The roller mechanism 100 will be described in detail later.

  In addition to the various devices described above, the printer 1 includes a ROM (Read Only Memory) that stores a control program (OS program) and the like of the printer 1, a RAM (Random Access Memory) that temporarily stores data, and A CPU (Central Processing Unit) that reads the above control program from the ROM and executes it, and receives a predetermined instruction information from an external device or the operation unit of the printer 1 to control the entire apparatus ( (Not shown) etc. are built in.

  FIG. 2 is an enlarged detailed view of the roller mechanism 100, and is a perspective view of the side wall plate portion 120 inside the paper conveyance path 17 shown in FIG. However, FIG. 2 shows a state in which a biasing member 105 described later is removed. As shown in FIG. 2, the roller mechanism 100 includes a driving roller 101, a driven roller 102, a shaft body 103, a support member 104, an urging member 105 (see FIG. 3) described later, and the like. The drive roller 101 is a pair of rollers that are driven by a predetermined drive motor or the like and arranged perpendicularly to the conveyance direction of the paper conveyance path 17 (disposed horizontally in the paper conveyance path 17) (FIG. 2). In this case, the driving roller 101 is located in the sheet conveyance path 107 behind the side wall plate portion 120 and a part of the driving roller 101 is visible), and the pair of driving rollers 101 are rotationally driven in conjunction with each other. It has come to be. Further, the drive roller 101 is a so-called rubber roller formed of, for example, a rubber material that can ensure a predetermined frictional force against the sheet to be caught in the nip portion 110.

  The driven roller 102 is a pair of rollers disposed so as to face the pair of driving rollers 101, and a so-called boss portion 1021 formed in a cylindrical shape is formed at the center of rotation of the roller. Yes. The driven roller 102 is a resin roller (resin roller) made of, for example, a POM (Polyoxymethylene) material, and the leading edge of the conveyed paper is brought into contact with the surface of the driven roller 102, and the rotation of this roller In addition, an operation of sliding the sheet toward the nip portion 110 while being slid is easily performed.

  The shaft body 103 supports a pair of driven rollers 102 while being bridged, and is a shaft made of a predetermined metal material or the like. The shaft body 103 rotatably supports each driven roller 102 in the vicinity of both end portions (inside both end portions). A bearing portion 1031 (journal) having, for example, a cylindrical shape (or a plurality of circular collars) is formed at a portion of the shaft body 103 that supports the driven roller 102. The boss portion 1021 is rotatably fitted. In addition, the left and right end portions of the shaft body 103 are formed with supported portions 1032 that are substantially rectangular when viewed in axial section, and the supported portions 1032 are loosely fitted into cutout groove portions 1041 of the support member 104 described later. It has become. Note that the cross-sectional shape of the supported portion 1032 (shaft body 103) is not limited to the rectangular shape, and various shapes such as a square shape, a polygonal shape having five or more corners, and an ellipse can be employed. However, depending on the shape of the supported portion 1032, various shapes can be adopted for the notch groove portion 1041.

  The support member 104 supports the shaft body 103 (at the supported portions 1032 at both ends), and the left and right sides from the side wall plate portion 120 of the paper transport path 17 toward the inside (opposite direction of the arrow A). It is a pair of plate-shaped bodies (sheet metal) which are erected at predetermined intervals. The support member 104 is formed with a notch groove portion 1041 (slit) having a substantially rectangular shape in a side view that is opened toward the inside at a substantially central portion in the vertical direction, and in the notch groove portion 1041 of the shaft body 103. The supported portion 1032 is inserted with a predetermined clearance (gap). However, in this embodiment, the upper side and the lower side of the “rectangle” of the supported portion 1032 are fitted so as to be substantially parallel (horizontal) to the upper side and the lower side of the “rectangular” of the cutout groove portion 1041. The support member 104 may be configured to be supported on both inner sides of the driven roller 102 instead of being supported on the left and right outer sides of the pair of driven rollers 102 as shown in FIG.

  The urging member 105 is fixed so as to come into contact with the shaft body 103 so as to intersect with the shaft body 103 and urges the driven roller 102 toward the driving roller 101 together with the shaft body 103. The urging member 105 is fixed in a state of being hooked on the hooked portion 121 provided on the side wall plate portion 120. The hooked portion 121 is provided at a vertical position across the shaft body 103 as viewed in the direction of the arrow A, and has a shape that allows a hooking portion 1052 of an urging member 105 described below to be hooked (here, in the vertical direction). The belt-like body is formed in a mountain shape projecting inward.

  In addition, the part shown by the code | symbol 106 in the side wall board part 120 is what the side wall board part 120 is bent inside, and, thereby, the paper which passed the nip part 110 is conveyed suitably downstream. That is, the leading edge of the paper is caught in this place, and jamming or the like does not occur.

  Here, the urging member 105 will be described in detail with reference to FIGS. 3 and 4. FIG. 3 is a detailed view showing an example of the urging member 105. 4 is a schematic side view showing an example of a state in which the urging member 105 shown in FIG. 3 is attached to the hooked portion 121 of the roller mechanism 100 shown in FIG.

  The urging member 105 is a so-called tension spring (coil spring) formed in a coil shape (spring shape), and includes a pressing surface portion 1051 and a latching portion 1052 as shown in FIG. The pressing surface portion 1051 is centered from the shaft body 103 toward the nip portion 110 (an arrow shown in FIG. 4) in a state where the urging member 105 is fixed to the side wall plate portion 120 so as to come into contact with the shaft body 103. A biasing force (hereinafter referred to as an eccentric force) in a direction deviated from the T direction (horizontal direction), that is, a direction deviated obliquely from the center direction (in the direction of arrow H shown in FIG. 4) is applied to the shaft body 103. Thus, a pressing surface for pressing against the shaft 103 is configured.

  The pressing surface portion 1051 includes a small-diameter portion 1053, a large-diameter portion 1054 having a larger coil diameter than the small-diameter portion 1053, and a tapered portion 1055 having a substantially truncated cone shape formed from the small-diameter portion 1053 to the large-diameter portion 1054. These are integrally formed as a concentric shaft as a tension spring (main body). Note that the ratio of the small diameter portion 1053, the large diameter portion 1054, and the tapered portion 1055 in the pressing surface portion 1051 (width of each portion in the concentric axis direction) is not limited to that shown in FIG. 3, and the tapered portion 1055 is, for example, the pressing surface portion 1051. In other words, the narrower portion 1053 and the larger diameter portion 1054 may be narrower and the tapered portion 1055 may be wider.

  The hooking portions 1052 are hooks provided at both ends of the pressing surface portion 1051, and here, so-called round hooks are employed. However, it is not limited to a round hook, and various hook shapes such as a semi-round hook, a V hook, or a square hook can be adopted. Moreover, the position of the opening part of each said hook may be arrange | positioned on the same side instead of mutually arrange | positioning as shown in FIG. Furthermore, the number of hooks may not be one at each end, but may be two or more.

  As shown in FIG. 4, the urging member 105 configured as described above includes a pressing surface portion 1051, particularly a tapered portion 1055 (or a boundary portion between the small diameter portion 1053 and the tapered portion 1055 indicated by reference numeral 1056 in FIG. 3). The hooking portion 1052 is hooked on the hooked portion 121 while being in contact with the outer surface of the shaft body 103 (surface opposite to the nip portion 110). At this time, the pressing surface portion 1051 is in an extended state, and the eccentric force is generated based on a force (contraction force) for returning from the extended state to the original state.

  Here, the latching portion 1052 on the small diameter portion 1053 side is latched on the latching portion 121 disposed on the upper side, and the latching portion 1052 on the large diameter portion 1054 side is latched on the latching portion 121 disposed on the lower side. Therefore, the generated eccentric force acts on the shaft body 103 from the center direction shown in the arrow T direction to the direction biased in the arrow H direction. As a result, the shaft body 103 The upper surface portion 1033 of the supported portion 1032 is pressed against the upper end edge portion 1042 of the notch groove portion 1041. However, not only the upper end edge portion 1042 of the notch groove portion 1041 but also the side surface portion 1034 of the supported portion 1032 may be in contact with the bottom end edge portion 1043 of the notch groove portion 1041.

  By the way, the generation of the sound is likely to occur with respect to a roller unit provided in a conveyance path arranged in a vertical direction (vertical direction) such as a sheet conveyance path 17 as shown in FIG. This is because the conveyance direction of the paper is opposite to the direction in which gravity acts, and for example, the roller drive (the paper passes through the nip portion) causes the notch groove 1041 and the supported portion 1032 to move. This is because, within the range of the clearance, the operation in which the driven roller is lifted upward and the operation in which the driven roller in the lifted state is dropped by gravity are repeatedly vibrated. Therefore, in the roller mechanism 100 disposed in the paper conveyance path 17, as shown in FIG. 4, the shaft body 103 (supported portion 1032) is directed toward the paper conveyance direction (upward), that is, a notch. It is preferable to apply an eccentric force so as to press the groove portion 1041 toward the upper end edge portion 1042 side.

  However, the lower end edge portion 1044 (or the lower end edge portion 1044 and the bottom end edge portion 1043) of the notch groove 1041 is opposite to the above-described case even if it is disposed in the vertical conveyance path in this way. It is good also as a structure which applies eccentric force so that it may press toward the side. In this case, the direction of the urging member 105 to be hooked on the hooked portion 121 is opposite to that in FIG. 4, that is, the hooked portion 1052 on the large diameter portion 1054 side is connected to the upper hooked portion 121. The latching portion 1052 on the small diameter portion 1053 side is latched to the latched portion 121 on the lower side.

  Note that the state in which the urging member 105 is attached (fixed) is not limited to the state illustrated in FIG. 4. For example, the pressing surface portion 1051 until the positions of both end portions of the urging member 105 come close to the position of the hooked portion 121. May be in a stretched state.

  Further, regarding the attachment of the urging member 105, the hooking portion 1052 of the urging member 105 may be in any form as long as it can be fixed to the hooked part 121 without being in the form of the hook. For example, a form that is fixed by screws or the like, or a form that is fixed (fixed) by welding or the like may be used. In accordance with this, the hooked portion 121 also has a configuration (shape) according to each fixing form of the hooking portion 1052.

  Further, the arrangement of the hooked portions 121 in the side wall plate portion 120 may not be arranged in series in the vertical direction, as shown in FIGS. However, it may be arranged so as to be shifted in the form of upper and lower steps with respect to the surface of the side wall plate portion 120. However, when shifting to this stepped shape, the eccentric position caused by the taper of the taper portion 1055 is obtained by setting the latching position of the biasing member 105 on the large diameter portion 1054 side to be lower than the latching position on the small diameter portion 1053 side. Together with the force, a stronger eccentric force can be generated.

  By the way, the above-mentioned “eccentric force” is roughly expressed as a force that is pushed straight in the center direction (arrow T direction) and a force that is pushed in an oblique direction (depending on the degree of taper) by the tapered surface. It is a combined force. Actually, the biasing member 105 is moved in various directions according to the coil shape (unevenness caused by the coil winding state), the surface shape of the shaft body 103, or the latching position (latching direction) of the latching portion 1052. A force (biasing force) is generated, and the resultant force becomes an eccentric force.

  The urging member 105 is not limited to that shown in FIG. 3 as long as it is configured to generate an eccentric force in this way, and various shapes can be adopted. In this regard, the biasing member may have a shape shown in FIG. 5, for example. In the urging member 200 shown in FIG. 5, the pressing surface portion 201 has its outer diameter gradually changed from a small diameter to a large diameter from one end side to the other end side of the urging member 105. ) It has been formed. In other words, it can be said that the pressing surface portion 201 is composed of only the tapered portion 1055 without the small diameter portion 1053 and the large diameter portion 1054. However, in FIG. 5, the pressing surface portion 201 has a tapered shape in which the outer diameter increases linearly, that is, a conical shape (conical frustum shape) as the gradually changed shape, but is not limited thereto. For example, the outer diameter may be increased in a curved shape.

  Moreover, the shape shown in FIG. 6 may be sufficient as an urging | biasing member, for example. This urging member 300 has a pressing surface portion 301 arranged on a concentric shaft at a predetermined interval (not necessarily spaced) in the middle of the cylindrical portion 302 and the cylindrical portion 302, respectively. For example, the shape is composed of two spherical portions 303 and 304 (which may be elliptical spheres) that are different in (mountain height). When the urging member 300 is attached to the roller mechanism, the shaft body is brought into contact with, for example, a recessed portion indicated by reference numeral 305 (a side wall portion inside the spherical portions 303 and 304) of the pressing surface portion 301. Thereby, the eccentric force can be generated by a (virtual) tapered portion having an inclination as indicated by reference numeral 306.

  As described above, according to the roller mechanism of the present invention, in the roller unit composed of the driving roller 101 and the driven roller 102 opposed to the driving roller 101, the attachment is fixed so as to come into contact with the shaft body 103 of the driven roller 102. The biasing member 105 is eccentric with respect to the central direction from the shaft body 103 toward the nip portion 110 between the driven roller 102 and the driving roller 101 with respect to the shaft body 103 by the pressing surface portion 1051 of the biasing member 105. A biasing force (eccentric force) acts in the direction. Accordingly, in a simpler configuration in which the biasing member 105 having the pressing surface portion 1051 is used, for example, by applying a biasing force in a direction eccentric from the center direction to the shaft body 103, for example, a predetermined roller unit The shaft body 103 of the driven roller 102 supported by the support member 104 with a clearance so as to ensure the nip amount of the nip is always provided on one side (peripheral edge portion) of the notch groove portion 1041 (support portion) of the support member 104. It becomes possible to energize in the pressed state, and the generation of sound (abnormal noise) due to the vibration of the shaft body 103 (in the notch groove portion 1041) via the driven roller 102 when the paper passes through the nip portion 110 or the like. Can be prevented.

  Further, the shaft body 103 of the driven roller 102 is supported in a state of loosely fitting in the notch groove portion 1041 of the support member 104, and the shaft body 103 is supported by the biasing force in the eccentric direction by the biasing member 105. Since it is abutted (pressed) on one side edge (for example, the upper edge 1042 shown in FIG. 4), or one side edge (upper edge 1042) and the bottom edge (bottom edge 1043), The driven roller 102 and the shaft body 103 vibrate when the sheet passes through the nip portion 110 and the shaft body 103 vibrates and comes into contact with the peripheral edge portion of the notch groove portion 1041 (clearance). Can be prevented.

  The pressing surface portion 1051 of the urging member 105 includes a small-diameter portion 1053 on one end side of the urging member 105, a large-diameter portion 1054 on the other end side, and a tapered portion 1055. The biasing member 105 (pressing surface portion 1051) is provided with a taper portion 1055 to apply a biasing force to the shaft body 103 in an eccentric direction with respect to the central direction from the center 103 toward the nip portion 110. This can be easily performed by a simple configuration in which the shaft body 103 is urged while being in contact therewith.

  In addition, the pressing surface portion 201 of the urging member 200 is gradually changed from a small diameter to a large diameter from one end side to the other end side of the urging member 200. The pressing surface portion 201 can be formed, for example, in a tapered shape by a simple configuration of gradually changing from a small diameter to a large diameter, and in a direction eccentric with respect to the central direction from the shaft body 103 toward the nip portion 110. This urging force can be easily applied to the shaft body 103 by a simple configuration in which the gradually pressingly deformed, for example, the tapered pressing surface portion 201 is urged against the shaft body 103.

  Furthermore, since the biasing member 105 (200, 300) is a tension spring formed in a coil shape, the biasing member 105 can be realized with a simpler configuration. In addition, this invention can take the following aspects.

  (A) The roller mechanism 100 in the above embodiment is not applied only to the one arranged in the paper conveyance path arranged in the vertical direction, but includes the paper conveyance path etc. arranged in the horizontal direction. The present invention can be applied to those arranged at various places.

  (B) The biasing member 105 (200, 300) may be not limited to a tension spring as long as it is attached and generates a biasing force, and is made of a predetermined elastic material, for example, a flexible elastic rubber. It may be. Also in this case, of course, the pressing surface portion is formed in the shape shown in FIGS. 3, 5, and 6 and is configured to be able to generate an eccentric force as described above.

  (C) The driven roller 102 is preferably a resin roller, but is not limited thereto, and may be a rubber roller similar to the drive roller 101, for example. The drive roller 101 is not limited to a rubber roller. In short, any roller unit including a driving roller and a driven roller may be used.

  (D) A single shaft body 103 (roller unit) is urged by a plurality of (for example, two) urging members 105 (a plurality of hooked portions 121 are also provided correspondingly). It may be a configuration. In this case, a stronger urging force (eccentric force) in a direction decentered with respect to the central direction from the shaft body 103 toward the nip portion 110 can be applied to the shaft body 103 and left and right (1 The pair of driven rollers 102 can be more stably pressed against the driving roller 101, and generation of noise (abnormal noise) due to vibration of the shaft body 103 (driven roller 102) can be more reliably prevented. it can.

1 is a schematic configuration diagram of a printer showing an example of an image forming apparatus to which a roller mechanism according to the present invention is applied. It is an enlarged detail drawing of a roller mechanism.

FIG. 2 is a perspective view showing an appearance of the printer, and particularly shows a detailed structure of a paper tray and an opening / closing cover.
It is detail drawing which shows an example of a biasing member. FIG. 4 is a schematic side view showing an example of a state in which the urging member shown in FIG. 3 is attached to the hooked portion of the roller mechanism shown in FIG. 2. It is a figure which shows one modification of a biasing member. It is a figure which shows one modification of a biasing member. It is a figure which shows the conventional urging | biasing member.

Explanation of symbols

1 Printer (image forming device)
DESCRIPTION OF SYMBOLS 2 Developing device 3 Photoconductor drum 10 Drive roller 11 Driven roller 16 Fixing roller pair 17 Paper conveyance path 100 Roller mechanism 101 Drive roller 102 Driven roller 1021 Boss part 103 Shaft body 1031 Bearing part 1032 Supported part 1033 Upper surface part 1034 Side face part 104 Support member 1041 Notch groove 1042 Upper edge (one side edge)
1043 Bottom edge (bottom edge)
1044 Lower edge (one side edge)
105 Biasing member (tension spring)
1051 Holding surface part (holding surface part according to claim 3)
1052 Latching part 1053 Small diameter part 1054 Large diameter part 1055 Tapered part 107 Paper transport path 110 Nip part 120 Side wall plate part 121 Engaged part 200, 300 Biasing member (tensile spring)
201 holding surface part (holding surface part according to claim 4)
301 Pressing surface portion 302 Cylindrical portion 303 Spherical portion 400 Coil spring

Claims (6)

A roller unit composed of a driving roller and a driven roller facing the driving roller;
A roller mechanism that includes a biasing member that is fixed so as to abut against the shaft of the driven roller and biases the driven roller toward the drive roller together with the shaft;
In the biased state, the biasing member is configured to apply a biasing force in a direction eccentric to the center direction from the shaft body toward the nip portion of the driven roller and the drive roller to the shaft body. A roller mechanism having a holding surface portion. A support member that has a predetermined notch groove portion and supports the shaft body in a state of loosely fitting in the notch groove portion;
2. The biasing member according to claim 1, wherein the biasing member abuts the shaft body on one side edge of the notch groove portion, or the one side edge and the bottom edge by a biasing force in the eccentric direction. The roller mechanism described.   The pressing surface portion of the urging member includes a small diameter portion on one end side of the urging member, a large diameter portion on the other end side, and a tapered portion extending from the small diameter portion to the large diameter portion. The roller mechanism according to claim 1 or 2.   The roller according to claim 1 or 2, wherein the pressing surface portion of the urging member is gradually changed from a small diameter to a large diameter from one end side to the other end side of the urging member. mechanism.   The roller mechanism according to claim 3 or 4, wherein the urging member is a tension spring formed in a coil shape.   An image forming apparatus comprising the roller mechanism according to claim 1.

Images