JP6003748B2 - Conveying device, fixing device, image forming apparatus - Google Patents

Description

  The present invention relates to a conveyance device, a fixing device, and an image forming apparatus.

  Patent Document 1 includes a heating roll that heats a recording medium, an endless belt that pressurizes the heating roll, and a gear unit that is attached to the heating roll and rotates in response to an external force. A fixing device is disclosed that rotates as the gear unit rotates due to frictional force with the gear unit resulting from deformation of at least one of the gear unit and the heating roll.

JP 2012-133035 A

  An object of the present invention is to suppress damage to the first gear and the second gear that mesh with each other.

The invention according to claim 1 is a conveyance member, a conveyance roll that receives a load from the conveyance member and conveys the conveyance object by rotating the conveyance object between the conveyance member and the conveyance roll. A first gear provided on an outer periphery of the transport roll so as to have a gap between the outer peripheral surface of the transport roll, a transmission unit that transmits a rotational force from the first gear to the transport roll, and The first gear is engaged with the first gear on the side opposite to the conveying member, the driving force from the driving unit is transmitted to the first gear to rotate the first gear, and the first gear is moved to the opposite side. A second gear to be limited, a first abutting portion provided coaxially with the first gear and having a first cylindrical surface, provided coaxially with the second gear, abutting against the first cylindrical surface, Has a second cylindrical surface for maintaining the distance between the first gear and the second gear. A second abutting portion that is a feeding device comprising a.

  According to a third aspect of the present invention, there is provided the fixing device as the conveying device according to the first or second aspect, wherein the conveying roll heat-fixes an image formed on the recording medium as the conveyed object to the recording medium.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising: a forming unit that forms an image on a recording medium; and the fixing device according to the third aspect that fixes an image formed by the forming unit to the recording medium. .

  According to the structure of Claim 1 of this invention, compared with the case where the 2nd gear in this structure is not provided, the failure | damage of the 1st gear and 2nd gear which mesh | engage with each other can be suppressed.

According to the structure of Claim 1 of this invention, compared with the case where the 1st butting part and 2nd butting part in this structure are not provided, the failure | damage of the 1st gear and 2nd gear which mesh | engage mutually can be suppressed.

  According to the configuration of the third aspect of the present invention, it is possible to suppress the fixing failure caused by the breakage of the first gear and the second gear as compared with the case where the second gear in the present configuration is not provided.

  According to the configuration of the fourth aspect of the present invention, it is possible to suppress the image defect due to the fixing defect as compared with the case where the fixing device in the present configuration is not provided.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. It is a disassembled perspective view which shows the heating roll and pressure belt which concern on this embodiment, and its support structure. It is a perspective view which shows the heating roll and pressure belt which concern on this embodiment, and its support structure. It is the figure which looked at the axial direction cross section of the heating roll and pressure belt which concern on this embodiment. It is a disassembled perspective view which shows the structure of the axial direction edge part of the heating roll which concerns on this embodiment. It is a sectional side view which shows the structure of the axial direction edge part of the heating roll which concerns on this embodiment. It is the figure which looked at the drive transmission part which concerns on this embodiment in the axial direction. FIG. 8 is a diagram illustrating a state where a nip load is not applied in the configuration illustrated in FIG. 7. It is the figure which looked at the drive transmission part which concerns on a comparative example in the axial direction. It is a perspective view which shows the structure which concerns on a 1st modification. It is a side view which shows the structure which concerns on a 1st modification. It is a sectional side view showing the composition concerning the 2nd modification. It is a sectional side view showing the composition concerning the 3rd modification.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

(Configuration of image forming apparatus 10)
First, the configuration of the image forming apparatus 10 according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of the image forming apparatus 10. Note that an arrow UP shown in the drawing indicates a vertically upward direction.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 11 (housing) in which each component is housed. Inside the image forming apparatus main body 11, a storage unit 12 that stores a recording medium P such as paper, an image forming unit 14 (an example of a forming unit) that forms an image on the recording medium P, and an image from the storage unit 12. A transport unit 16 that transports the recording medium P to the forming unit 14 and a control unit 20 that controls the operation of each unit of the image forming apparatus 10 are provided. In addition, a discharge unit 18 for discharging the recording medium P on which an image is formed by the image forming unit 14 is provided on the upper portion of the image forming apparatus main body 11.

  The image forming unit 14 includes image forming units 22Y, 22M, 22C, and 22K (hereinafter referred to as 22Y to 22K) that form toner images of colors of yellow (Y), magenta (M), cyan (C), and black (K). The intermediate transfer belt 24 to which the toner images formed by the image forming units 22Y to 22K are transferred, and the first transfer for transferring the toner images formed by the image forming units 22Y to 22K to the intermediate transfer belt 24. A roll 26 and a second transfer roll 28 for transferring the toner image transferred to the intermediate transfer belt 24 by the first transfer roll 26 from the intermediate transfer belt 24 to the recording medium P are provided. The image forming unit 14 is not limited to the above-described configuration, and may be another configuration as long as it forms an image on the recording medium P.

  The image forming units 22 </ b> Y to 22 </ b> K are arranged side by side at the center in the vertical direction of the image forming apparatus 10 while being inclined with respect to the horizontal direction. Each of the image forming units 22Y to 22K includes a photoreceptor 32 that rotates in one direction (for example, the clockwise direction in FIG. 1). Since the image forming units 22Y to 22K are configured in the same manner, the reference numerals of the respective portions in the image forming units 22M, 22C, and 22K are omitted in FIG.

  Around each photoconductor 32, a charging roll 23 as a charging device for charging the photoconductor 32 and the photoconductor 32 charged by the charge roll 23 are exposed in order from the upstream side in the rotation direction of the photoconductor 32. An exposure device 36 that forms an electrostatic latent image on the photosensitive member 32; a developing device 38 that develops the electrostatic latent image formed on the photosensitive member 32 by the exposure device 36 to form a toner image; And a removing member 40 that removes the toner remaining on the photosensitive member 32.

  The exposure device 36 is configured to form an electrostatic latent image based on the image signal sent from the control unit 20. Examples of the image signal sent from the control unit 20 include an image signal acquired by the control unit 20 from an external device.

  The developing device 38 includes a developer supply body 38A that supplies the developer to the photoconductor 32, and a plurality of transport members 38B that transport the developer applied to the developer supply body 38A while stirring.

  The intermediate transfer belt 24 is formed in an annular shape and is disposed on the upper side of the image forming units 22Y to 22K. On the inner peripheral side of the intermediate transfer belt 24, winding rolls 42 and 44 around which the intermediate transfer belt 24 is wound are provided. The intermediate transfer belt 24 is circulated and moved (rotated) in one direction (for example, counterclockwise in FIG. 1) while being in contact with the photosensitive member 32 by rotating one of the winding rolls 42 and 44. It has become. The winding roll 42 is an opposing roll that faces the second transfer roll 28.

  The first transfer roll 26 faces the photoconductor 32 with the intermediate transfer belt 24 interposed therebetween. A space between the first transfer roll 26 and the photoconductor 32 is a first transfer position where the toner image formed on the photoconductor 32 is transferred to the intermediate transfer belt 24.

  The second transfer roll 28 faces the winding roll 42 with the intermediate transfer belt 24 interposed therebetween. A space between the second transfer roll 28 and the winding roll 42 is a second transfer position where the toner image transferred to the intermediate transfer belt 24 is transferred to the recording medium P.

  The transport unit 16 is disposed along the transport path 48 and is transported along a transport roll 48 for transporting the recording medium P stored in the storage section 12, a transport path 48 for transporting the recording medium P transported to the transport roll 46. A plurality of transport rolls 50 are provided for transporting the recording medium P delivered by the roll 46 to the second transfer position.

  As an example of a transport device that transports the recording medium P (an example of a transported body) downstream of the second transfer position in the transport direction, a toner image transferred to the recording medium P by the second transfer roll 28 is recorded on the recording medium P. There is provided a fixing device 60 for fixing the toner. A discharge roll 52 for discharging the recording medium P on which the toner image is fixed to the discharge unit 18 is provided on the downstream side in the transport direction of the fixing device 60. A specific configuration of the fixing device 60 will be described later.

  Next, an image forming operation for forming an image on the recording medium P in the image forming apparatus 10 according to the present embodiment will be described.

  In the image forming apparatus 10 according to the present embodiment, the recording medium P sent out from the storage unit 12 by the sending roll 46 is sent to the second transfer position by the plurality of conveying rolls 50.

  On the other hand, in the image forming units 22 </ b> Y to 22 </ b> K, the photosensitive member 32 charged by the charging roll 23 is exposed by the exposure device 36 to form an electrostatic latent image on the photosensitive member 32. The electrostatic latent image is developed by the developing device 38 to form a toner image on the photoreceptor 32. The color toner images formed by the image forming units 22Y to 22K are superimposed on the intermediate transfer belt 24 at the first transfer position to form a color image. Then, the color image formed on the intermediate transfer belt 24 is transferred to the recording medium P at the second transfer position.

  The recording medium P to which the toner image has been transferred is conveyed to the fixing device 60, and the transferred toner image is fixed by the fixing device 60. The recording medium P on which the toner image is fixed is discharged to the discharge unit 18 by the discharge roll 52. As described above, a series of image forming operations are performed.

(Configuration of Fixing Device 60)
Next, the configuration of the fixing device 60 (an example of a transport device) according to the present embodiment will be described.

  As shown in FIGS. 2 and 3, the fixing device 60 according to the present embodiment includes a recording medium P (an example of a conveyance target) between a pressure belt 66 (an example of a conveyance member) and the pressure belt 66. ) With a heating roll 64 (an example of a conveyance roll) that transports the recording medium P, a roll support portion 70 that supports the heating roll 64, and a belt support portion 80 that supports the pressure belt 66. Yes.

(Heating roll 64)
The heating roll 64 is composed of a cylindrical roll member, and includes a cylindrical base body 64A and an elastic layer 64B formed on the outer periphery of the base body 64A. A heating source 65 (see FIG. 4) such as a halogen lamp for heating the heating roll 64 is provided in the internal space of the heating roll 64.

  The base 64A is formed of a thin cylindrical body. The base body 64A is elastically deformed by the pressure applied by the pressure belt 66, and is restored to a cylindrical shape by its own rigidity in a non-pressurized state where no pressure is applied by the pressure belt 66, and has a high thermal conductivity. Consists of materials. Specifically, the base body 64A is formed of a metal material such as iron, nickel, nickel steel, stainless steel (SUS), or aluminum. A support member that supports the base body 64A is not disposed on the inner periphery of the base body 64A.

  The elastic layer 64B is made of a heat-resistant elastic body and covers the axially central side of the outer periphery of the base body 64A. That is, the outer peripheral surface at both axial end portions 64D of the base body 64A is exposed. The elastic layer 64B is made of a rubber material such as silicone rubber or fluorine rubber, for example. The heating roll 64 fixes the toner image by sandwiching the recording medium P between the elastic layer 64B and the pressure belt 66. Note that a release layer (not shown) is formed on the outer peripheral surface of the elastic layer 64B so that the recording medium P can be easily peeled off.

  In order to transmit the driving force (rotational force) from the driving motor 120 (an example of the driving unit) to the heating roll 64 at one end 64D in the axial direction of the base body 64A (end on the upper left side in FIGS. 2 and 3). Drive transmission unit 100 is provided. The specific configuration of the drive transmission unit 100 will be described later.

  Both end portions 64D in the axial direction of the base body 64A are supported portions that are supported by a slide bearing 76 described later. One end 64D in the axial direction of the base body 64A on the arrangement side of the drive transmission unit 100 is supported by a slide bearing 76 described later on the center side in the axial direction from the position where the later-described roll side gear 102 of the drive transmission unit 100 is attached. It has become so.

(Pressure belt 66)
The pressure belt 66 is an endless belt that rotates following the heating roll 64. Specifically, the pressure belt 66 is made of a polymer such as polyimide, polyamide, or polyimideamide, or a metal such as SUS, nickel, or copper. Note that a release layer (not shown) is formed on the outer peripheral surface of the pressure belt 66 to facilitate the separation of the recording medium P.

(Roll support part 70)
The roll support unit 70 includes a pair of side plates 72 disposed on both axial ends of the heating roll 64 and a plurality of connection plates 74 disposed between the pair of side plates 72 and connecting the pair of side plates 72. It is configured.

  The pair of side plates 72 are respectively formed with recesses 75 that are cut out in an arc shape and open upward. A pair of side plates 72 are each attached with a slide bearing 76 formed in an arc shape along the recess 75. The slide bearing 76 rotatably supports both end portions 64D of the heating roll 64 in the axial direction.

  A shaft portion 73 for rotatably supporting the belt support portion 80 is provided at one end portion of the pair of side plates 72 (end portion on the upper right side in FIGS. 2 and 3).

  An attachment portion 78 to which one end portion of a tension spring 99 as an urging member (elastic member) is attached is provided at the other end portion of the pair of side plates 72 (the end portion on the lower left side in FIGS. 2 and 3). It has been. Specifically, the attachment portion 78 is configured by a recess formed in the pair of side plates 72. A hook 99 </ b> A formed at one end of the tension spring 99 is hooked on the mounting portion 78 formed of a recess.

(Belt support part 80)
The belt support portion 80 is disposed along the axial direction (rotational axis direction) of the pressure belt 66 and includes an inner peripheral support portion 90 that supports the pressure belt 66 on its inner periphery and an inner peripheral support portion 90. And a pair of side plates 82 as supports that are supported at both ends of the pressure belt 66 in the axial direction.

  As shown in FIG. 4, the inner circumferential side support portion 90 includes a pressure body 92 (pressure pad) disposed on the heating roll 64 side on the inner circumference of the pressure belt 66, and the pressure body 92 and the pressure body 92. A low friction sheet 94 as a film body disposed between the belt 66, a guide member 96 disposed on the inner circumference of the pressure belt 66 on the side opposite to the heating roll 64, and a pressure body 92 And a holder 98 as a holding portion for holding the friction sheet 94 and the guide member 96.

  The pressure body 92 has a length along the axial direction of the pressure belt 66, and is formed in a substantially rectangular shape (block shape) in a side view (axial view) as shown in FIG. Yes. On the heating roll 64 side of the pressurizing body 92 (on the diagonally lower left side in FIG. 4), a facing surface 92 </ b> A that faces the heating roll 64 through the low friction sheet 94 and the pressurizing belt 66 is formed. The facing surface 92A functions as a pressing surface pressed against the heating roll 64 side.

  The holder 98 is formed in an L shape in a side view and has a length along the axial direction of the pressure belt 66. At both ends in the longitudinal direction of the holder 98, projecting portions 98A (see FIG. 2) projecting outward in the longitudinal direction are formed.

  The low friction sheet 94 has a length along the axial direction of the pressure belt 66, and is disposed between the facing surface 92 </ b> A of the pressure body 92 and the inner peripheral surface of the pressure belt 66.

  The guide member 96 has a length along the axial direction of the pressure belt 66. The guide member 96 includes a peripheral wall 96A that is in sliding contact with the inner peripheral surface of the rotating pressure belt 66. The peripheral wall 96A is formed along a part of the circumferential direction of the pressure belt 66, and a portion in contact with the pressure belt 66 is along the circumferential direction of the peripheral wall 96A (the rotation direction of the pressure belt 66). A plurality of ribs 96B and 96C are formed.

  Between the rib 96B and the rib 96C in the peripheral wall 96A, an impregnation member 95 impregnated with lubricating oil supplied to the inner peripheral surface of the pressure belt 66 is disposed. The impregnation member 95 is made of, for example, sponge or felt.

  Further, at both ends in the longitudinal direction of the holder 98, as shown in FIG. 2, a restricting member 88 for restricting the axial movement of the pressure belt 66 is provided. The limiting member 88 is attached to the holder 98 by inserting the protruding portion 98 </ b> A of the holder 98 into the insertion hole 88 </ b> A formed in the limiting member 88. The limiting member 88 projects outward in the radial direction from the outer peripheral surface of the guide member 96 in a state where the limiting member 88 is mounted on the holder 98. Thus, when the pressure belt 66 moves in the axial direction, the side end of the pressure belt 66 hits the limiting member 88 so that the movement of the pressure belt 66 in the axial direction is limited.

  The pair of side plates 82 are formed with insertion grooves 86 into which the projecting portions 98A of the holder 98 can be inserted from the diagonally lower left side in FIG. Each of the protrusions 98 </ b> A is inserted into the insertion grooves 86 of the pair of side plates 82, so that the inner peripheral side support portion 90 that supports the pressure belt 66 is supported by the pair of side plates 82. As a result, the pressure belt 66 is rotatably supported by the belt support portion 80.

  Further, at one end of the pair of side plates 82 (ends on the lower right side in FIG. 2), supported holes 83 as supported portions supported by the shaft portions 73 of the side plates 72 in the roll support portion 70 are respectively provided. Is formed. By inserting the shaft portion 73 into the supported hole 83, the pair of side plates 82 are supported so as to be rotatable around the shaft of the shaft portion 73 with respect to each of the pair of side plates 72.

  Furthermore, attachment portions 81 to which the other ends of the tension springs 99 are attached are provided at the other ends of the pair of side plates 82 (ends on the upper left side in FIG. 2). Specifically, the attachment portion 81 is configured by a through hole that penetrates the pair of side plates 82. A hook 99 </ b> B formed at the other end of the tension spring 99 is hooked on the mounting portion 81 configured by a through hole. When the pair of side plates 82 and the pair of side plates 72 are pulled by the tension spring 99, the pressure belt 66 is pressed against the heating roll 64, and the heating roll 64 receives the load (pressing force) of the pressure belt 66. It has become.

  In this state, the heating roller 64 is rotationally driven by the drive transmission unit 100 and the pressure belt 66 is driven to rotate by the heating roller 64, whereby the recording medium P to which the toner image is transferred becomes the heating roller 64 and the pressure belt. 66 and is conveyed between the two. The recording medium P sandwiched and transported between the heating roll 64 and the pressure belt 66 is heated with the toner by the heating roll 64 and pressurized with the pressure belt 66, and the heating roll 64 and the pressure belt 66. The image is fixed in the nip area.

  The fixing device 60 includes a moving mechanism (not shown) that moves the side plate 82 in the direction away from the side plate 72 against the urging force of the tension spring 99. The pressure state of the pressure belt 66 against the heating roll 64 is released by a moving mechanism (not shown). The moving mechanism (not shown), for example, moves the side plate 82 in the direction away from the side plate 72 (arrow X direction in FIG. 3) by a mechanism that pushes or pulls the overhanging portion 85 that protrudes outward in the axial direction from the pair of side plates 82. It is supposed to let you. In the present embodiment, the nip load between the heating roll 64 and the pressure belt 66 may be adjusted by a moving mechanism (not shown).

(Drive transmission unit 100)
As shown in FIGS. 5 and 6, the drive transmission unit 100 is a roll side gear 102 (an example of a first gear) to which a driving force (rotational force) from a driving motor 120 (see FIG. 2) is transmitted (input). ), A coil-like coil spring 104 (an example of a transmission portion) into which the axial end 64D of the heating roll 64 is inserted, and a coil mounted on the axially outer portion (left portion in FIG. 6) of the roll-side gear 102. And a restricting member 106 that restricts the spring 104 from coming off the heating roll 64.

  The roll side gear 102 includes a cylindrical gear main body 102E, a cylindrical portion 102C that is formed on the axially inner side (right side in FIG. 6) of the gear main body 102E and extends in the axial direction of the heating roll 64 (left and right direction in FIG. 6). have.

  A tooth portion 102F that meshes with a tooth portion 122A (see FIG. 2) of the motor-side gear 122 that outputs the driving force of the drive motor 120 is formed on the outer periphery of the gear body 102E. An accommodation recess 102A for accommodating the coil spring 104 is formed on the inner peripheral side of the gear body 102E, and the inner diameter of the gear body 102E is made larger than the outer diameter of the base body 64A of the heating roll 64 by the accommodation recess 102A. ing.

  Further, as shown in FIG. 5, an insertion portion 102B into which a later-described protrusion 104A of the coil spring 104 accommodated in the accommodation recess 102A is inserted is formed on the inner wall forming the outer edge of the accommodation recess 102A in the gear body 102E. Has been. As shown in FIG. 6, the inner diameter of the cylindrical portion 102C is larger than the outer diameter of the base body 64A of the heating roll 64, and the inner peripheral surface of the cylindrical portion 102C and the outer peripheral surface of the base body 64A of the heating roll 64 are A gap S1 is formed between them. That is, the roll-side gear 102 is provided on the outer periphery of the heating roll 64 so as to have a gap S <b> 1 between the outer peripheral surface of the heating roll 64. The inner diameter of the cylindrical portion 102C is the same as the inner diameter of the slide bearing 76.

  As shown in FIG. 5, the coil spring 104 has a protruding portion 104 </ b> A whose one end protrudes radially outward of the heating roll 64. The protrusion 104A is inserted into the insertion portion 102B, so that the rotation of the coil spring 104 around the axis with respect to the roll side gear 102 is restricted.

  The inner diameter of the coil spring 104 is smaller than the outer diameter of the base body 64A of the heating roll 64 when the coil spring 104 is not loaded. That is, the coil spring 104 is fitted to the base body 64 </ b> A of the heating roll 64 by an interference fit. On the other hand, the outer diameter of the coil spring 104 is formed to be smaller than the inner diameter of the gear body 102E of the roll side gear 102. That is, in the state where the coil spring 104 is accommodated in the gear main body 102E, a gap S2 is generated between the outer peripheral surface of the coil spring 104 and the inner peripheral surface of the gear main body 102E.

  The coil spring 104 is configured in a coil shape that is wound in the rotational direction of the roll side gear 102 (in the direction of arrow B in FIG. 5). In other words, the coil spring 104 receives a rotational force that is rotated in the reduction direction (arrow B direction in FIG. 5) in which the inner diameter is reduced from the roll side gear 102 through the protrusion 104A, and rotates together with the roll side gear 102. It is supposed to be.

  Therefore, the coil spring 104 is deformed so that the rotational force in the reduction direction is transmitted from the roll-side gear 102 and the inner diameter is reduced, and is brought into close contact with the outer peripheral surface of the heating roll 64. Thereby, the coil spring 104 rotates the heating roll 64 by a frictional force with the outer peripheral surface of the heating roll 64.

  When the rotation of the roll side gear 102 stops, the inner diameter of the coil spring 104 is expanded and the contact state between the coil spring 104 and the outer circumferential surface of the heating roll 64 is released. As described above, the coil spring 104 functions as a spring clutch in driving transmission to the heating roll 64.

  Note that when the roll side gear 102 rotates in the reverse direction (rotates in the direction opposite to the reduction direction), the inner diameter of the coil spring 104 becomes large and idles with respect to the heating roll 64.

  The restricting member 106 is formed in a disc shape, and has a function of restricting the movement of the coil spring 104 to the outside in the axial direction so that the coil spring 104 housed in the housing recess 102A does not come off from the housing recess 102A. Have. That is, when the coil spring 104 moves outward in the axial direction, one end of the coil spring 104 in the axial direction hits the limiting member 106 so that further movement of the coil spring 104 in the axial direction is restricted. It has become. Further, the limiting member 106 is configured to limit the movement of the heating roll 64 in the axial direction (left side in FIG. 6) with respect to the roll-side gear 102 when it hits the end face 64E of the heating roll 64.

  Note that the axial side of the roll side gear 102 with respect to the heating roll 64 (see FIG. 6) is provided on the outer side in the axial direction of the limiting member 106 (left side in FIG. 6) and the end of the heating roll 64 on the side where the limiting member 106 is not provided. A restricting member (not shown) for restricting the relative movement of the left side in FIG. This prevents the roll side gear 102 from being detached from the heating roll 64. The limiting member (not shown) is fixed to the image forming apparatus main body 11.

  Further, as shown in FIGS. 2 and 3, the drive transmission unit 100 transmits (inputs) the driving force (rotational force) from the driving motor 120 to the roll side gear 102 (motor side gear 122 (second gear). Example). Here, in the present embodiment, as shown in FIGS. 3 and 7, the motor side gear 122 is disposed at a position opposite to the pressure belt 66 with respect to the roll side gear 102.

  Specifically, one tooth tip (tip portion) of the tooth portion 102F of the roll side gear 102 and the tooth portion 122A of the motor side gear 122 is on the other tooth root (root portion) of the tooth portion 102F and the tooth portion 122A. By at least hitting, the movement of the roll side gear 102 toward the slide bearing 76 is restricted.

  2 and 3, the motor side gear 122 may be a gear attached to the drive shaft 120A of the drive motor 120, or from the drive motor 120 via one or more gears. A gear to which the driving force is transmitted may be used. That is, when the driving force of the driving motor 120 is transmitted to the roll-side gear 102 by the gear train (a plurality of gears), the motor-side gear 122 is a gear arranged at the final stage of the gear train.

(Operation according to this embodiment)
Next, the operation according to this embodiment will be described.

  In the present embodiment, as shown in FIG. 7, when the nip load F from the pressure belt 66 is acting on the heating roll 64, the pressure belt 66 side portion of the heating roll 64 (FIG. 7). The lower part) is crushed. The portion of the heating roll 64 on the slide bearing 76 side (the upper portion in FIG. 7) is expanded in diameter by being pressed against the slide bearing 76. The sliding bearing 76 side portion of the heating roll 64 has an outer diameter along the sliding surface of the sliding bearing 76 and the inner wall of the cylindrical portion 102 </ b> C of the roll side gear 102. Further, the heating roll 64 is pressed over a half circumference of the cylindrical portion 102 </ b> C of the roll side gear 102 so that the position of the roll side gear 102 is determined.

  On the other hand, when the side plate 82 is moved away from the side plate 72 (in the direction of arrow X in FIG. 3) against the urging force of the tension spring 99 by a moving mechanism (not shown), the nip load F from the pressure belt 66 is increased. Does not act on the heating roll 64. In this state, as shown in FIG. 8, the heating roll 64 is restored to a circular shape when viewed in the axial direction. When the heating roll 64 is restored to a circular shape, there is a gap S1 between the outer peripheral surface of the axial one end portion 64D of the heating roll 64 and the inner peripheral surface of the roll side gear 102. Positioning by the roll 64 is not performed.

  Therefore, in the comparative example (see FIG. 9) in which the motor side gear 122 is not disposed at the opposite position (upper side in FIG. 9) to the side opposite to the pressure belt 66 with respect to the roll side gear 102, it hits the outer peripheral surface of the heating roll 64. Movement of the roll side gear 102 to the sliding bearing 76 side is allowed in the range. Thereby, when the nip load F from the pressure belt 66 is acting (see FIG. 9A) and when the nip load F from the pressure belt 66 is not acting (see FIG. 9A). ) May cause a deviation W of the roll side gear 102.

  On the other hand, in the present embodiment, as shown in FIG. 8, the motor side gear 122 is disposed at the opposite position on the opposite side of the pressure belt 66 with respect to the roll side gear 102. When the nip load F is not applied, the roll side gear 102 which is going to move to the opposite side hits the motor side gear 122, and the movement of the roll side gear 102 to the slide bearing 76 side is restricted. Specifically, at least one tooth tip of the tooth part 102F of the roll side gear 102 and the tooth part 122A of the motor side gear 122 hits the other tooth bottom of the tooth part 102F and the tooth part 122A, so that the roll side The movement of the gear 102 toward the slide bearing 76 is limited.

As a result, regardless of whether the nip load F from the pressure belt 66 is acting on the heating roll 64, the meshing state of the roll side gear 102 and the motor side gear 122 is unlikely to change, and the roll side gear The distance between the shafts 102 and the motor side gear 122 can be kept constant. For this reason, even when the heating roll 64 is driven to rotate after the nip load F is applied to the state where the nip load F is not applied, the roll side gear 102 and the motor side gear 122 are damaged or the roll side Tooth skipping between the gear 102 and the motor side gear 122 is suppressed. Further, since the distance between the shafts of the roll side gear 102 and the motor side gear 122 can be kept constant, the heating roll 64 can be rotated stably even if the nip load, the driving torque conditions, and the like are changed.
7, 8, and 9, the gap between the outer peripheral surface of the heating roll 64 and the inner peripheral surface of the roll-side gear 102 is exaggerated for easy understanding of the operation.

(First Modification of Drive Transmission Unit 100)
In the drive transmission unit 100 described above, the motor side gear 122 is in contact with the roll side gear 102 at the tooth portion 122A to limit the movement of the roll side gear 102. However, in the drive transmission unit 150 according to the first modification, As shown in FIGS. 10 and 11, the movement of the roll side gear 102 is limited at portions other than the tooth portion 122 </ b> A.

  Specifically, in the drive transmission unit 150 according to the first modification, the cylindrical portion 102C provided coaxially with the gear body 102E of the roll side gear 102 functions as a first abutting portion having a first cylindrical surface 102D. It is supposed to be. The outer diameter of the cylindrical portion 102C is larger than the outer diameter of the tooth tip circle of the gear body 102E.

  Furthermore, the drive transmission unit 150 according to the first modified example includes an abutting portion 124 (an example of a second abutting portion) that is provided coaxially with the motor-side gear 122 and abuts against the cylindrical portion 102C. The abutting portion 124 has a second cylindrical surface 124A that abuts against the first cylindrical surface 102D of the cylindrical portion 102C. The second cylindrical surface 124 </ b> A abuts against the first cylindrical surface 102 </ b> D of the cylindrical portion 102 </ b> C, thereby restricting the movement of the roll-side gear 102 toward the slide bearing 76, and between the axes of the roll-side gear 102 and the motor-side gear 122. The distance D is maintained. The sum of the outer diameter D1 of the abutting portion 124 and the outer diameter D2 of the cylindrical portion 102C is twice the inter-axis distance D between the roll side gear 102 and the motor side gear 122.

  According to the configuration of the first modified example, the movement of the roll side gear 102 toward the slide bearing 76 side is restricted by the abutting portion 124 abutting against the cylindrical portion 102C, so the tooth portion 102F of the roll side gear 102 and the motor side The load in the direction orthogonal to the axial direction does not act on the tooth portion 122A of the gear 122, and damage to the roll side gear 102 and the motor side gear 122 is suppressed.

  The motor side gear 122 may be configured to limit the movement of the roll side gear 102 by both the abutting portion 124 and the tooth portion 122A. That is, it is sufficient that the movement of the roll side gear 102 is limited at least one of the abutting portion 124 and the tooth portion 122A.

(Second Modification of Drive Transmission Unit 100)
In the drive transmission unit 100 described above, the driving force from the drive motor 120 is transmitted to the heating roll 64 by the coil spring 104 as the transmission unit. However, in the drive transmission unit 200 according to the second modification, FIG. As shown in the figure, the driving force from the driving motor 120 is transmitted to the heating roll 64 by using a driving transmission rubber 202 (high friction member) as a transmitting portion.

  The drive transmission rubber 202 is formed in an annular shape (ring shape) and is accommodated in the accommodating recess 102 </ b> A of the roll side gear 102. The drive transmission rubber 202 is fixed to the inner wall of the roll-side gear 102 and has a gap S <b> 1 with respect to the heating roll 64.

In a state where the nip load F from the pressure belt 66 is applied to the heating roll 64, the axial end 64 </ b> D of the heating roll 64 is pressed against the drive transmission rubber 202, and the inner periphery of the drive transmission rubber 202. Adheres to the surface and increases the frictional force between them. Due to such rubber friction, the driving force of the roll side gear 102 is transmitted to the heating roll 64 via the drive transmission rubber 202.
(Third Modification of Drive Transmission Unit 100)
In the drive transmission unit 100 described above, the driving force from the drive motor 120 is transmitted to the heating roll 64 by the coil spring 104 serving as the transmission unit. However, in the drive transmission unit 300 according to the third modification, FIG. As shown in the figure, the driving force from the driving motor 120 is transmitted to the heating roll 64 by using the protruding portion 310 and the groove portion 320 as the transmitting portion.

The protrusion 310 is formed on the outer peripheral surface of the heating roll 64 and protrudes outward in the radial direction of the heating roll 64. The groove 320 is formed on the inner peripheral surface of the gear body 102E of the roll side gear 102, and the protrusion 310 can be fitted therein. Also in this configuration, a gap S <b> 3 is formed between the outer peripheral surface of the heating roll 64 and the inner peripheral surface of the roll-side gear 102.
Note that the protrusion 310 may be formed on the inner peripheral surface of the gear body 102 </ b> E, and the protrusion 310 may be formed on the outer peripheral surface of the heating roll 64. In addition, at least one of the protruding portion 310 and the groove portion 320 is formed in plural along the circumferential direction of the heating roll 64.

  In this configuration, in a state where the nip load F from the pressure belt 66 is acting on the heating roll 64, the protrusion 310 of the heating roll 64 fits into the groove 320 of the roll side gear 102, and the protrusion 310 is By pushing the inner wall of the groove 320, the driving force of the roll side gear 102 is transmitted to the heating roll 64.

(Other variations)
In the above embodiment, the pressure belt 66 is used as the conveying member. However, the present invention is not limited to this, and for example, a pressure roll may be used.

  In the above embodiment, the fixing device 60 is used as the transport device. However, the present invention is not limited to this, and the transport device may be a device having a function other than fixing in addition to the transport function of transporting the transported object. An apparatus having only a transport function may be used.

  In the above-described example, the coil spring 104, the drive transmission rubber 202 (second modified example), the projecting portion 310, and the groove portion 320 (as a transmission portion that transmits the rotational force (driving force) from the roll side gear 102 to the heating roll 64. Although the third modified example is used, the present invention is not limited to this, and other configurations may be used.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made. For example, the modification examples described above may be appropriately combined.

10 Image forming apparatus 60 Fixing apparatus (an example of a conveying apparatus)
64 Heating roll (an example of a transport roll)
66 Pressure belt (an example of a conveying member)
102 Roll side gear (example of first gear)
102C Cylindrical part (an example of the first butting part)
102D 1st cylindrical surface 120 Drive motor (an example of a drive part)
122 Motor side gear (example of second gear)
124A Second cylindrical surface 124 Abutting portion (an example of a second abutting portion)

Claims (4)

A conveying member;
A transport roll that receives a load from the transport member and transports the transported body by rotating the transported body between the transport member and the transport member;
A first gear provided on the outer periphery of the transport roll so as to have a gap with the outer peripheral surface of the transport roll;
A transmission unit for transmitting a rotational force from the first gear to the transport roll;
The first gear engages with the first gear on the opposite side of the conveying member, transmits the driving force from the drive unit to the first gear, rotates the first gear, and the first gear toward the opposite side. A second gear that restricts movement of one gear;
A first abutting portion provided coaxially with the first gear and having a first cylindrical surface;
A second abutting portion that is provided coaxially with the second gear and has a second cylindrical surface that abuts against the first cylindrical surface and maintains an interaxial distance between the first gear and the second gear;
A transport apparatus comprising:   A conveying member;
  A transport roll that receives a load from the transport member and transports the transported body by rotating the transported body between the transport member and the transport member;
  A first gear provided on the outer periphery of the transport roll so as to have a gap with the outer peripheral surface of the transport roll;
  A transmission unit for transmitting a rotational force from the first gear to the transport roll;
  The first gear engages with the first gear on the opposite side of the conveying member, transmits the driving force from the drive unit to the first gear, rotates the first gear, and the first gear toward the opposite side. A second gear that restricts movement of one gear;
  With
  The shaft of the first gear and the shaft of the second gear are arranged side by side along the direction in which the load from the transport member acts on the transport roll as viewed in the axial direction of the transport roll.
  Conveying device. The fixing device as a transport device according to claim 1, wherein the transport roll heat-fixes an image formed on a recording medium as the transported body to the recording medium. A forming unit for forming an image on a recording medium;
The fixing device according to claim 3, wherein the image formed by the forming unit is fixed on the recording medium.
An image forming apparatus comprising:

Images