JP5966993B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

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

2. Description of the Related Art An image forming apparatus such as a copying machine or a printer is known which includes a discharge device that includes a contact member that relaxes curl by contacting a recording medium (see, for example, Patent Document 1).
Also, a fixing device is known in which pressing means for preventing curling is provided on a paper discharge tray (see, for example, Patent Document 2).
Further, there is known an image forming apparatus that corrects curl of a sheet that has been curled by passing through a fixing device by using a sheet guide (see, for example, Patent Document 3).

JP 2012-91891 A JP 2011-133794 A JP-A-7-277777

  An object of the present invention is to provide a fixing device and an image forming apparatus capable of correcting a curl of a recording medium.

According to the first aspect of the present invention, a rotating body, an endless belt that circulates with a recording medium sandwiched between the rotating body, and an inner peripheral side of the endless belt are arranged along the rotation axis direction of the rotating body. A pressure member made of a single component that pressurizes the endless belt toward the rotating body, and is disposed downstream of the rotating body in the transport direction of the recording medium, and transports the recording medium. A contact forming portion that contacts the recording medium toward the rotating body, and on the opposite side of the endless belt side on the downstream side in the rotation direction with respect to the contact forming portion. a recessed recess, the recess viewed portion of the endless belt on the downstream side in the rotational direction and a pressing portion for pressing toward the rotating body than the recess portion, the pressure member the endless When the belt is pressed toward the rotating body, the endless belt And provided that are spaced apart by the contact-making portion, of the common tangent of the rotating body and the conveying roll in a side view, through the pressure member of the rotating body is arranged side In the fixing device, the common tangent is positioned upstream of the contact point in the rotating body in the rotation direction, and the pressing portion is positioned downstream of the contact point in the rotation direction.

According to a second aspect of the present invention, in the fixing device according to the first aspect, the pressure portion is disposed on the rotating body side of the common tangent.

The invention according to claim 3, an image forming section for forming the unfixed toner image on the recording medium, wherein according to the unfixed toner image to claim 1 or claim 2 is fixed on the recording medium An image forming apparatus comprising a fixing device.

  According to the first aspect of the present invention, it is possible to obtain a conveying apparatus that can correct curl as compared with the case where the present configuration is not provided.

According to the invention described in claim 2, as compared with the case not having this configuration, the transport device is obtained more curl straightening is performed.

According to the third aspect of the present invention, an image forming apparatus capable of correcting curl is obtained.

1 is a schematic configuration diagram showing an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of a heating roll and a pressure belt housed in a fixing device main body of the fixing device according to the embodiment. 1 is a schematic side view showing a fixing device according to an embodiment. The schematic perspective view of a pressurization body. FIG. 4 is a diagram illustrating a conveyance state of a recording medium in a fixing device.

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

  In FIG. 1, an image forming apparatus 10 includes an image forming apparatus main body 11 in which each component is housed. Inside the image forming apparatus main body 11, an accommodating portion 12 that accommodates a recording medium P such as paper, an image forming portion 14 that transfers a toner image that is an example of an unfixed toner image on the recording medium P, and undetermined And a fixing device 60 for fixing the received toner image to the recording medium P.

  Further, a transport unit 16 that transports the recording medium P from the storage unit 12 to the image forming unit 14 and a control unit 20 that controls the operation of each unit of the image forming apparatus 10 are provided. Further, 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). And an intermediate transfer belt 24 to which the toner images formed by the image forming units 22Y to 22K are transferred, and a first transfer roll for transferring the toner images formed by the image forming units 22Y to 22K to the intermediate transfer belt 24 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. The image forming unit 14 is not limited to the above-described configuration, and may have another configuration as long as it transfers an unfixed toner image onto 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 parts of the image forming units 22M, 22C, and 22K are omitted in FIG.

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

  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 in one direction (for example, counterclockwise in FIG. 1) while being in contact with the photosensitive member 32 when one of the winding rolls 42 and 44 is rotationally driven. Yes. 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. There are provided a plurality of transport rolls 50 for transporting the recording medium P sent out by the roll 46 to the second transfer position.

  A fixing device 60 that fixes the toner image transferred to the recording medium P by the second transfer roll 28 to the recording medium P is provided on the downstream side in the transport direction from the second transfer position. Further, the fixing device 60 is provided with a discharge roll 52 that discharges the recording medium P on which the toner image is fixed to the discharge unit 18. 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 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)
In FIG. 1, a fixing device 60 according to the embodiment includes a fixing device main body 62 provided with each component. FIG. 2 is a perspective view of a heating roll 64 that is an example of a rotating body housed in the fixing device main body 62 of the fixing device 60 and a pressure belt 66 that is an example of an endless belt, and FIG. A schematic side view is shown. In FIG. 2, the heating roll 64 rotates around the rotation axis AR. The direction of the rotation axis AR is indicated by a solid line double arrow. Moreover, the rotation direction R of the heating roll 64 is shown by the solid line arrow in FIG.

  The fixing device 60 includes a heating roll 64, a pressure belt 66 that circulates with the recording medium P interposed between the heating rolls 64, and an inner peripheral side of the pressure belt 66 along the direction of the rotation axis AR of the heating roll 64. And a pressure member 80 that pressurizes the pressure belt 66 toward the heating roll 64 and a downstream side of the heating roll 64 in the conveyance direction of the recording medium P, and discharges the recording medium P to the outside. A discharge roll 52 is provided. The discharge roll 52 includes a discharge roll 52A and a discharge roll 52B, and discharges the recording medium P to the outside with the recording medium P sandwiched between the discharge roll 52A and the discharge roll 52B.

  In addition, the pressurizing member 80 contacts the recording medium P toward the heating roll 64, and the pressurizing belt 66 faces the heating roll 64 on the downstream side in the rotation direction R from the contact forming section 82 </ b> A. And a pressurizing part 82B for pressurizing. 82 A of contact formation parts are more than the contact T in the heating roll 64 of the common tangent C which passes along the side by which the pressurization member 80 of the heating roll 64 is arrange | positioned among the common tangents of the heating roll 64 and the discharge roll 52 in a side view. Located on the upstream side in the rotational direction R, the pressurizing part 82B is located on the downstream side in the rotational direction R with respect to the contact point T. In FIG. 3, the common tangent line C is indicated by a two-dot chain line.

  The fixing device 60 includes a heating source 64 </ b> B that heats at least one of the heating roll 64 and the pressure belt 66. In the region where the pressure belt 66 is pressed toward the heating roll 64, an unfixed toner image is generated. It is heated and fixed on the recording medium P. In the embodiment, the area to be pressurized is an area in which the pressure belt 66 is pressurized toward the heating roll 64 by the contact forming unit 82A and the pressure unit 82B. In the embodiment, the heating source 64B is provided inside the heating roll 64, but the pressure belt 66 may be heated by the heating source.

  An unfixed toner image is heated by the heating roll 64 and an unfixed toner image is pressed by the pressure belt 66 on the recording medium P that is sandwiched and conveyed by the heating roll 64 and the pressure belt 66. The toner image is fixed in the pressure region of the heating roll 64 and the pressure belt 66.

  Next, a specific configuration of the heating roll 64 and the pressure belt 66 and a support structure for the heating roll 64 and the pressure belt 66 will be described in detail.

  2 and 3, the heating roll 64 includes a cylindrical cylindrical member 64A and a heating source 64B such as a halogen lamp provided in the internal space of the cylindrical member 64A. The cylindrical member 64A is made of a metal material such as aluminum or stainless steel. A gear 64C for transmitting a rotational force from a drive motor (not shown) to the cylindrical member 64A is attached to one end of the cylindrical member 64A in the axial direction.

  2 and 3, the cylindrical member 64 </ b> A has both end portions in the axial direction as supported portions 64 </ b> D supported by the slide bearing 68.

  A covering member 64E that covers the outer peripheral surface of the cylindrical member 64A is provided between the supported portions 64D on both ends in the axial direction of the cylindrical member 64A. The covering member 64E is made of an elastic material such as rubber.

  The fixing device main body 62 shown in FIG. 1 is provided with a support 70 that supports the heating roll 64 and the pressure belt 66. The support 70 includes a roll support member 74 that supports the heating roll 64, and a pressure belt 66 and a belt support member 76.

  The roll support member 74 includes a pair of side plates 74A that are disposed on both axial ends of the heating roll 64 and support the heating roll 64, and a connection plate 74B that is disposed between the pair of side plates 74A and couples the pair of side plates 74A. I have.

  Slide bearings 68 are respectively attached to the pair of side plates 74A. The slide bearing 68 rotatably supports the supported portion 64D of the cylindrical member 64A.

  A shaft portion 74J that rotatably supports the belt support member 76 is provided at one end of the pair of side plates 74A.

  An attachment portion 74E to which one end portion of the tension spring 90 is attached is provided at the other end portion of the pair of side plates 74A. Specifically, the mounting portion 74E is formed of a recess formed in the pair of side plates 74A. A hook 90 </ b> A formed at one end of the tension spring 90 is hooked on the mounting portion 74 </ b> E configured by a recess.

  The belt support member 76 includes a pair of side plates 76 </ b> A disposed on both ends of the pressure belt 66 in the axial direction.

  The pressure belt 66 is supported by the belt support member 76 at a position facing the heating roll 64 so as to be able to go around the fixing device main body 62 shown in FIG. In the heating roll 64 and the pressure belt 66, the heating roll 64 is driven to rotate, and the pressure belt 66 is driven and rotated by the heating roll 64, so that the recording medium P onto which the toner image is transferred is sandwiched and conveyed. It has a configuration.

  An attachment portion 76C to which the other end portion of the tension spring 90 is attached is provided at the other end portion of the pair of side plates 76A. Specifically, the attachment portion 76C includes a through hole that penetrates the pair of side plates 76A. A hook 90 </ b> B formed on the other end of the tension spring 90 is hooked on the mounting portion 76 </ b> C configured by a through hole.

  The pair of side plates 76A are formed with insertion grooves 76B into which a later-described plate body 84 can be inserted.

(Configuration of the pressure member 80)
In FIG. 3, a pressure member 80 that pressurizes the pressure belt 66 to the heating roll 64 is disposed along the rotation axis AR of the pressure belt 66 on the inner periphery of the pressure belt 66. The pressurizing member 80 includes a pressurizing body 82 disposed on the heating roll 64 side, and a plate body 84 having an L shape in side view provided on the pressurizing body 82.

  FIG. 4 shows a schematic perspective view of the pressure member 82. The pressurizing body 82 has a length along the direction of the rotation axis AR of the heating roll 64 and is formed in a substantially rectangular shape (block shape) in a side view. On the heating roll 64 side of the pressurizing body 82, a contact forming portion 82A and a pressurizing portion 82B are formed. Here, although not shown in detail, the contact forming portion 82A and the pressurizing portion 82B are formed as contact surfaces.

  An insertion groove 82 </ b> C into which the plate body 84 is inserted is formed along the longitudinal direction of the pressure body 82 on the side away from the heating roll 64 of the pressure body 82. The insertion groove 82 </ b> C is disposed on the downstream side in the rotation direction R of the pressure belt 66 in the pressure body 82. The plate body 84 has a length along the direction of the rotation axis AR of the heating roll 64.

  The pair of side plates 76A of the belt support member 76 shown in FIGS. 2 and 3 and the pair of side plates 74A of the roll support member 74 are pulled by the tension spring 90, whereby the pressure member 80 rotates the rotation shaft of the pressure belt 66. The pressure belt 66 is pressed against the heating roll 64 by applying a load (pressure) at both ends in the direction.

  Since the pressurizing body 82 is applied with pressure from the plate body 84 inserted into the insertion groove 82C, the pressurizing portion 82B causes the pressurizing belt 66 to be attached to the second portion in the portion where the insertion groove 82C is disposed. Pressurize with pressure to maximize pressure. As a result, as shown in FIG. 4, the pressure F applied to the heating roll 64 of the pressure belt 66 is maximized at the pressure unit 82 </ b> B in a side view along the rotation axis direction of the pressure belt 66.

  The contact forming unit 82A is disposed on the upstream side in the transport direction with respect to the pressurizing unit 82B, and the pressurizing belt 66 is moved to the heating roll 64 so that the pressurizing belt 66 contacts the recording medium P with the heating roll 64. Pressurization is performed at a first pressure smaller than the second pressure. When the recording medium P is not present at the position where the contact forming portion 82A is disposed, there is a gap between the heating roll 64 and the pressure belt 66, or the heating roll 64 and the pressure belt 66 are in contact with each other. It is a state of not to do.

  FIG. 5 is a diagram illustrating a conveyance state of the recording medium P in the fixing device 60. In FIG. 5, the conveyance path of the recording medium P is indicated by a thick broken line arrow. 3 and 5, the fixing device 60 includes a paper guide 100A located on the downstream side of the heating roll 64 and the pressure belt 66, and a paper guide 100B located on the upstream side.

  In FIG. 5, the recording medium P is guided by the paper guide 100 </ b> A and is conveyed along the outer periphery of the heating roll 64 to the position where the contact forming portion 82 </ b> A is disposed. The contact forming unit 82 </ b> A pressurizes the pressure belt 66 so that the recording medium P contacts the heating roll 64. The recording medium P is advanced along the heating roll 64 to the position of the pressure unit 82B while being curved.

  The pressurizing part 82B is located downstream of the contact point T in the rotation direction R. Further, the contact forming portion 82 </ b> A is located upstream of the contact point T in the rotation direction R. Here, in the case of only the pressurizing unit 82B, if it is located downstream of the contact point T in the rotation direction R, it becomes difficult to draw the recording medium P conveyed from the upstream side, and the recording medium P Wraps around the heating roll 64.

  On the other hand, in the embodiment, since the contact forming part 82A is located on the upstream side in the rotation direction R from the contact point T in addition to the pressurizing part 82B, the recording medium P conveyed from the upstream side is drawn. Further, the recording medium P curled along the heating roll 64 is pressed by the pressure forming unit 82B via the pressure belt 66 using the contact forming unit 82A as a pressing part, and the curl generated along the heating roll 64 is reversed. Bend to. As a result, the recording medium P does not go in the direction of winding around the heating roll 64, but goes to the paper guide 100B located on the upstream side. The curl of the recording medium P is also corrected by hitting the paper guide 100B. Therefore, it is possible to obtain the fixing device 60 that can correct the curl of the recording medium P without adding components.

  The effect of correcting the curl generated in the recording medium P is greater as the distance in the rotation direction R where the heating roll 64 and the recording medium P are in contact with each other is longer.

  The speed of the paper discharge roll 52 and the heating roll 64 is basically the same speed, but the speed of the paper discharge roll 52 so that the recording medium P is slackened between the paper discharge roll 52 and the heat roll 64. May be reduced, or the speed of the discharge roll 52 may be increased in order to pull the recording medium P.

  The present invention is not limited to the above embodiment, and various modifications, changes, and improvements can be made. For example, instead of the pressurizing member 80 having the contact forming portion 82A and the pressurizing portion 82B, the contact formation is located upstream of the contact point T in the rotation direction R and pressurizes the pressure belt 66 toward the heating roll 64. There may be provided a member and a pressure member that is located downstream of the contact point T in the rotation direction R and pressurizes the pressure belt 66 toward the heating roll 64.

  Specifically, the presser on the upstream side of the tangent line T when the pressurizing unit 82B is pressed through the pressurizing belt 66 and bent in the opposite direction is not limited to the contact forming unit 82A, and may be other components. . For example, the belt support member 76 may be a protrusion provided along the direction of the rotation axis of the heating roll 64, or the pressurizing body 82 may include a contact forming member and a pressurizing member.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 14 ... Image forming part, 60 ... Fixing device, 64 ... Heating roll which is an example of rotating body, 64B ... Heat source, 66 ... Pressure belt which is an example of endless belt, 80 ... Pressure member , 82A ... contact forming part, 82B ... pressurizing part, AR ... rotating shaft, C ... common tangent, P ... recording medium, R ... rotating direction, T ... contact.

Claims (3)

A rotating body,
An endless belt that circulates around the recording medium between the rotating body,
A pressure member made of a single component that is arranged on the inner peripheral side of the endless belt along the rotation axis direction of the rotating body and pressurizes the endless belt toward the rotating body;
A transport roll that is disposed downstream of the rotating body in the transport direction of the recording medium and transports the recording medium;
The pressure forming member is configured to contact the recording medium toward the rotating body; and
A recess portion recessed on the side opposite to the endless belt side of the contact-making portion at the downstream side in the rotational direction, pressing toward the endless belt on the downstream side in the rotation direction than the depressions viewed portion to said rotating member A pressurizing part for pressing,
The indented portion is provided so as to be separated from the endless belt when the pressure member presses the endless belt toward the rotating body,
Of the common tangent lines between the rotating body and the transport roll in the side view,
A common tangent line passing through the side where the pressure member of the rotating body is disposed is positioned upstream of the contact point of the rotating body in the rotating direction, and the pressing portion is positioned downstream of the contact point in the rotating direction. A fixing device characterized by being located. The said pressurizing part is arrange | positioned at the said rotary body side of the said common tangent.
The fixing device according to 1 . An image forming unit for transferring an unfixed toner image onto the recording medium;
Claim to fix the toner image of the unfixed on the recording medium 1 or claim 2
An image forming apparatus comprising the fixing device described in 1.

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