JP5407134B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device used for, for example, a copying machine, a laser printer, a facsimile, and the like, and an image forming apparatus using the fixing device.

  Conventionally, as a fixing device used in an image forming apparatus, there are a heating roller heated by a heating unit and rotated by a driving unit, and a pressure roller that circumscribes the heating roller and rotates by the rotation of the heating roller. The recording material is sandwiched between the heating roller and the pressure roller, and the toner image is heated and melted and fixed on the recording material (Japanese Patent Laid-Open No. 2000-66545: Patent Document). 1).

In the heating roller, the surface of the central region in the width direction is smoothly formed, the surfaces of the regions in the both ends in the width direction are formed rough, and the friction coefficient between the heating roller and the recording material is determined in the central portion. I try to make it smaller. On the other hand, the surfaces of both end portions in the width direction of the pressure roller are formed smoothly.
JP 2000-66545 A

  However, in the conventional fixing device, the surfaces of both end portions of the heating roller are formed rough, whereas the surfaces of both end portions of the pressure roller are formed smoothly. When the recording material is passed between a roller and the pressure roller, the heating roller and the pressure roller are both ends of the heating roller corresponding to outside the recording material passage area and the pressure. There is a problem that the frictional resistance between the heating roller and the pressure roller is reduced because the contact is made only at both ends of the roller.

  Accordingly, the conveyance force of the recording material by the heating roller and the pressure roller is reduced, and slip occurs between the heating roller and the pressure belt, and the speed difference between the recording material and the heating roller. And image noise occurs.

  Further, if the width of both ends of the heating roller is increased in order to increase the conveying force of the recording material, there arises a problem that the width of the fixing device becomes large. On the other hand, if the pressing force of the recording material is increased, bending is prevented. Therefore, it is necessary to increase the frame strength of the fixing device, and it is necessary to increase the frame thickness, which causes a problem that the weight of the fixing device increases.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fixing device that can improve the image quality by preventing a recording material from passing through poorly and can be reduced in size and weight.

In order to solve the above problems, the fixing device of the present invention is:
A first rotating body and a second rotating body that form a nip portion that contacts each other to sandwich the recording material;
A driving unit that rotates the first rotating body and rotates the second rotating body following the rotation of the first rotating body;
Each of the first rotating body and the second rotating body is provided with a grip portion at least at one end in the rotating body width direction corresponding to the outside of the recording material passing range,
The outer diameter at the central portion in the width direction of the rotating body corresponding to the passing range of the recording material is constant,
The upper Symbol grip portion of the first rotary body and said second rotary member, the friction coefficient of the surface, is larger than the friction coefficient of the surface of the central portion of the rotary member widthwise, the grip portion The outer diameter of is gradually increased from the central portion side in the width direction of the rotating body toward the end face side in the width direction of the rotating body.

  Here, the said grip part is formed so that the outer diameter of the said grip part may become large in the end part side of the said rotary body width direction continuously or in steps, for example. Moreover, when the said grip part is formed in uneven | corrugated shape, let the outer diameter in the vertex of a convex part be the outer diameter of the said grip part.

  According to the fixing device of the present invention, each of the first rotating body and the second rotating body is provided with a grip portion at least at one end portion. The contact with the grip portion of the second rotating body can improve the frictional resistance between the grip portion of the first rotating body and the grip portion of the second rotating body, so that the first rotating body can be improved. The second rotating body can be reliably rotated by following the rotation of.

Further, the outer diameter of the grip portion gradually increases from the central portion side in the width direction of the rotating body toward the end face side in the width direction of the rotating body, so that when the recording material passes through the nip portion. Even if the distance between the first rotating body and the second rotating body is increased, the contact between the grip portion of the first rotating body and the grip portion of the second rotating body is maintained. The driving force can be transmitted from the first rotating body to the second rotating body, and the conveyance force can be secured.

  Therefore, even if the recording material having a small friction coefficient is passed through the nip portion, the conveying force of the recording material by the first rotating body and the second rotating body does not decrease, so the first rotation Slip between the body and the second rotating body is prevented, the speed difference between the recording material and the first rotating body is eliminated, and the occurrence of image noise is prevented. In addition, since it is not necessary to increase the conveyance force of the recording material, it is not necessary to increase the width of the grip portion, the width of the fixing device can be reduced and the size can be reduced, and the pressure contact force at the nip portion can be achieved. Therefore, it is not necessary to increase the frame strength of the fixing device to prevent bending, and the frame thickness can be reduced to reduce the weight.

  Thus, the frictional resistance between the first rotating body and the second rotating body outside the passing range of the recording material can be improved, and the passing quality of the recording material can be prevented to improve the image quality. In addition to the improvement, the fixing device can be reduced in size and weight.

In the fixing device of one embodiment,
The outer peripheral surface of the grip portion in the central portion side in the width direction of the rotating body and the outer peripheral surface of the central portion in the width direction of the rotating body are configured continuously.

In the fixing device of one embodiment,
The grip portion is provided at both ends of the first rotating body ,
The grip portion is provided at both ends of the second rotating body.

According to the fixing device in this embodiment, the grip portion is provided at both ends of the first rotating body, the grip portion is so provided on both end portions of the second rotary member, the The conveyance force of the recording material by the first rotating body and the second rotating body can be further improved, and the image quality can be further improved.

  In the fixing device according to an embodiment, the outer diameter of the grip portion of the at least one rotating body increases stepwise from the central portion in the rotating body width direction toward the end surface in the rotating body width direction.

  According to the fixing device of this embodiment, the outer diameter of the grip portion of the at least one rotating body increases stepwise from the central portion in the rotating body width direction toward the end surface in the rotating body width direction. Further, the conveying force of the recording material by the first rotating body and the second rotating body can be further improved, and the image quality can be further improved.

  In the fixing device according to the embodiment, the outer diameter of the grip portion of the at least one rotating body continuously increases from the central portion in the rotating body width direction toward the end surface in the rotating body width direction.

  According to the fixing device of this embodiment, the outer diameter of the grip portion of the at least one rotating body is continuously increased from the central portion in the rotating body width direction toward the end surface in the rotating body width direction. Further, the conveying force of the recording material by the first rotating body and the second rotating body can be further improved, and the image quality can be further improved.

  An image forming apparatus according to the present invention includes the fixing device.

  According to the image forming apparatus of the present invention, since the fixing device is provided, the image quality can be improved, and the size and weight can be reduced.

  According to the fixing device of the present invention, each of the first rotating body and the second rotating body is provided with a grip portion at least at one end, and the first rotating body or the second rotating body is provided. With respect to the grip portion of at least one of the rotating bodies, the outer diameter on the end surface side of the grip portion is larger than the outer diameter on the central portion side of the grip portion, and the maximum outer diameter of the grip portion is Since it is larger than the maximum outer diameter of the portion, the frictional resistance between the first rotating body and the second rotating body outside the passing range of the recording material can be improved, and the passing failure of the recording material can be prevented. Thus, the image quality can be improved and the fixing device can be reduced in size and weight.

  Also, according to the image forming apparatus of the present invention, since the fixing device is provided, the image quality can be improved, and the size and weight can be reduced.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a simplified configuration diagram showing an embodiment of an image forming apparatus according to the present invention. The image forming apparatus includes an image forming device 2 that forms an image by attaching unfixed toner to a recording material S, and a fixing device 1 that melts the toner and fixes the recording material S on the recording material S.

  The image forming apparatus 2 includes a photosensitive member 101, a developing device 104 that forms a toner image on the surface of the photosensitive member 101, and a transfer roller 105 that transfers the toner image on the photosensitive member 101 to the recording material S. Prepare.

  The fixing device 1 includes a heating roller 10 as a first rotating body, and an endless pressure belt as a second rotating body that circumscribes the heating roller 10 and rotates following the rotation of the heating roller 10. 20. The heating roller 10 and the pressure belt 20 are in contact with each other to form a nip portion N that sandwiches the recording material S. A separation claw 3 and a thermistor 4 are disposed on the outer peripheral surface of the heating roller 10.

  Next, the operation of this image forming apparatus will be described.

  The surface of the photosensitive member 101 is uniformly charged to a predetermined potential by a charger 102, and image exposure according to a document image is performed on the charged region from the image exposure device 103, and an electrostatic latent image is formed on the photosensitive member 101. Is formed. The electrostatic latent image is developed by the developing roller 141 to which a developing bias is applied in the developing device 104, and becomes a visible toner image.

  On the other hand, the recording material S is pulled out one by one by the paper feed roller 112 from the cassette 110 containing the recording material S such as recording paper and supplied to the pair of timing rollers 111. The timing roller 111 sends the recording material S between the photosensitive member 101 and the transfer roller 105 to which a transfer voltage is applied in synchronization with the toner image on the photosensitive member 101.

  Thereafter, the recording material S is passed through the mutual nip portion between the photoconductor 101 and the transfer roller 105, whereby a toner image is transferred to the recording material S. Subsequently, the fixing device 1 performs heating processing. A toner image is fixed on the recording material S under pressure.

  In the photoconductor 101, transfer residual toner and the like remaining on the photoconductor 101 after the transfer are removed and cleaned by a cleaner 107, and the residual electrification is erased by an eraser 108 to prepare for the next image formation.

  As shown in FIG. 2, the heating roller 10 is heated by a heater 7 serving as a heating unit disposed inside and rotated by a motor 8 serving as a driving unit. The pressing member 5 is disposed inside the pressure belt 20, and the pressing member 5 presses the pressure belt 20 toward the heating roller 10, so that the heating roller 10 and the pressure belt 20 are pressed. The nip portion N that sandwiches the recording material S is formed therebetween.

  The recording material S is conveyed by the nip portion N while melting and fixing the toner t of the recording material S. The recording material S is, for example, a sheet such as paper or an OHP sheet. The toner t is made of a material having heat melting properties such as a resin, a magnetic material, or a colorant.

  The heating roller 10 has at least a core metal and a surface layer. The core metal is preferably a metal such as aluminum or iron, has a pipe shape and a thickness of about 0.1 to 5 mm, and is preferably about 0.2 to 1.5 mm in consideration of weight reduction and warm-up time. .

  For the surface layer, fluorine tubes such as PFA, PTFE, ETFE, etc. may be used, and it is possible to impart release properties such as fluorine coating and silicone, and may have conductivity. . As for the thickness of the said surface layer, about 5-100 micrometers is desirable. Examples of fluorine-based tubes include PFA350-J, 451HP-J, and 951HP Plus manufactured by Mitsui DuPont Fluorochemical Co., Ltd. The surface roughness Ra of the surface layer is preferably about 0.01 to 50 μm.

  In addition, an intermediate layer may be provided between the surface layer and the cored bar, and the intermediate layer has elasticity such as silicone rubber or fluorine rubber, and is preferably made of a material having high heat resistance. Although it is arbitrary, about 0.05 to 2 mm is desirable, and the outer diameter is arbitrary, but about 10 to 50 mm is desirable.

  The pressure belt 20 has at least a base material and a surface layer. The base material is made of polyimide, polyphenylene sulfide, nickel, iron, or the like.

  For the surface layer, fluorine tubes such as PFA, PTFE, ETFE, etc. may be used, and it is possible to impart release properties such as fluorine coating and silicone, and may have conductivity. . As for the thickness of the said surface layer, about 5-100 micrometers is desirable. Examples of fluorine-based tubes include PFA350-J, 451HP-J, and 951HP Plus manufactured by Mitsui DuPont Fluorochemical Co., Ltd. The surface roughness Ra of the surface layer is preferably about 0.01 to 50 μm.

  In addition, an intermediate layer may be provided between the surface layer and the base material, and the intermediate layer has elasticity such as silicone rubber or fluororubber, and is preferably made of a material having high heat resistance. Although it is arbitrary, about 0.05 to 2 mm is desirable, and the outer diameter is arbitrary, but about 10 to 50 mm is desirable.

  A lubricant such as oil or grease may be applied to the inner surface of the pressure belt 20. The material of the oil and grease is arbitrary, but is fluorine, silicone, polyolefin, mineral oil, or the like.

  The pressing member 5 has an elastic pad 5a located on the upstream side in the conveyance direction of the recording material S and a rigid pad 5b located on the downstream side of the elastic pad 5a.

  The elastic pad 5a has elasticity such as silicone rubber and fluorine rubber, and is preferably made of a material having high heat resistance. The thickness is arbitrary, but is preferably about 0.1 to 10 mm.

  The rigid pad 5b is made of polyphenylene sulfide, resin such as polyimide or liquid crystal polymer, metal such as aluminum or iron, ceramic, or the like.

  The shapes of the elastic pad 5a and the rigid pad 5b are arbitrary. The elastic pad 5a and the rigid pad 5b may be integrally assembled on a support member made of a metal plate such as SUS, aluminum, or iron in terms of ease of assembly and productivity. In addition, you may arrange | position another heat source in this support member, and may arrange | position other rotary bodies, such as a roller.

  The shape of the nip N depends on the shape of the elastic pad 5a and the rigid pad 5b, the thickness of the rubber layer of the heating roller 10, the thickness of the elastic pad 5a, the pressure applied to the nip N, and the like. ,It is determined. Although the load concerning the said nip part N is arbitrary, 100-600N is desirable.

  As shown in FIG. 3, the heating roller 10 is provided with grip portions G1 (shown by hatching) at both end portions 12 in the width direction corresponding to the outside of the passing range of the recording material S. The grip portion G1 has a friction coefficient larger than the friction coefficient of the surface of the central portion 11 in the width direction corresponding to the passing range of the recording material S.

  The pressure belt 20 is provided with grip portions G <b> 2 (shown by hatching) at both end portions 22 in the width direction corresponding to outside the passing range of the recording material S. The grip portion G2 has a friction coefficient larger than the friction coefficient of the surface of the central portion 21 in the width direction corresponding to the passing range of the recording material S.

  The grip portions G1 and G2 are preferably arranged only outside the passing range of the recording material S. If toner is present on the surface of the recording material S, the toner melts to lower the coefficient of friction and deteriorate the transportability. Because it does. Note that the passing range of the recording material S is a range through which the recording material S having the maximum width that can be processed by the fixing device passes.

  The grip portions G1 and G2 are 1/100 to 3/10 of the entire width of the heating roller 10 and the pressure belt 20, respectively, and the fixing of the recording material S is ensured while ensuring the transportability. An increase in the size of the apparatus can be prevented. On the other hand, if it is smaller than 1/100, the transportability of the recording material S cannot be ensured. On the other hand, if it is larger than 3/10, there is a drawback that the fixing device is enlarged.

  A grip portion pressing portion 6 is provided that is positioned inside the grip portion G2 at both ends of the pressure belt 20 and presses the grip portion G2 of the pressure belt 20 toward the grip portion G1 of the heating roller 10. ing.

  Both end portions of the pressing member 5 are positioned inside both end portions 22 of the pressure belt 20, and grip portions G <b> 2 of the both end portions 22 of the pressure belt 20 are gripped by grips of the both end portions 12 of the heating roller 10. The grip part pressing part 6 is configured to press toward the part G1.

  As shown in FIGS. 4A and 4B, the heating roller 10 includes a cored bar 15, an elastic material 16, and a release material 17 in order from the inside. The core metal 15 is made of, for example, iron, the elastic material 16 is made of, for example, silicone rubber, and the release material 17 is made of, for example, a fluorine-based resin.

  The elastic material 16 has a recess in a portion corresponding to the central portion 11, and the release material 17 is located in the recess.

  That is, the end 12 is composed of the core metal 15 and the elastic material 16 in order from the inside. The central portion 11 includes the core metal 15, the elastic material 16, and the release material 17 in order from the inside.

  The grip portion G1 is made of the elastic material 16. The grip portion G1 has a hardness lower than that of the surface of the central portion 11. The grip portions G1 at both ends and the portion inside the center portion 11 are integrally connected, and the grip portion G1 and the inside portion of the center portion 11 are formed from the same elastic material 16. Become.

  For each of the grip portions G1 at both ends, the outer diameter of the grip portion G1 on the end surface side in the width direction of the heating roller 10 is larger than the outer diameter of the grip portion G1 on the center portion 11 side in the width direction of the heating roller 10. large. Further, the maximum outer diameter of the grip portion G1 is larger than the maximum outer diameter of the central portion 11.

  Further, the outer diameter of the grip portion G1 continuously increases from the central portion 11 in the width direction of the heating roller 10 toward the end surface in the width direction of the heating roller 10. That is, the outer peripheral surface of the elastic member 16 of the grip portion G1 is formed in an inclined shape.

  As shown in FIG. 5, the pressure belt 20 includes a base material 25, and an elastic material 26 and a release material 27 located outside the base material 25. The base material 25 is made of, for example, polyimide, the elastic material 26 is made of, for example, silicone rubber, and the release material 27 is made of, for example, fluorine resin.

  The elastic material 26 is located in a portion corresponding to the end portion 22, and the release material 27 is located in a portion corresponding to the central portion 21.

  That is, the end 22 is composed of the base material 25 and the elastic material 26 in order from the inside. The central portion 21 includes the base material 25 and the release material 27 in order from the inside.

  The grip portion G2 is made of the elastic material 26. The grip portion G2 has a hardness lower than that of the surface of the central portion 21.

  For each of the grip portions G2 at both ends, the outer diameter of the grip portion G2 on the end surface side in the width direction of the pressure belt 20 is the outer diameter of the grip portion G2 on the center portion 21 side in the width direction of the pressure belt 20. Bigger than. Further, the maximum outer diameter of the grip portion G2 is larger than the maximum outer diameter of the central portion 21.

  The outer diameter of the grip portion G2 continuously increases from the center portion 21 in the width direction of the pressure belt 20 toward the end surface in the width direction of the pressure belt 20. That is, the outer peripheral surface of the elastic member 26 of the grip portion G2 is formed in an inclined shape.

  The grip portion pressing portion 6 of the pressing member 5 is located inside the grip portion G2, and the grip portions G2 at both ends 22 of the pressure belt 20 are connected to the grip portions G1 at both ends 12 of the heating roller 10. Press toward.

  In this way, the friction coefficient can be increased by bringing the grip portions G1 and G2 made of silicone rubber into contact with each other. This is apparent from the relationship between the material and the friction coefficient, as shown in [Table 1] below.

[Table 1]

  According to the fixing device having the above-described configuration, the heating roller 10 and the pressure belt 20 are provided with the grip portions G1 and G2, respectively. Therefore, the grip portion G1 of the heating roller 10 and the pressure belt 20 The contact with the grip part G2 can improve the frictional resistance between the grip part G1 of the heating roller 10 and the grip part G2 of the pressure belt 20, and the pressure applied by the rotation of the heating roller 10 The belt 20 can be reliably rotated.

  Further, regarding the grip portions G1 and G2 of at least one of the heating roller 10 and the pressure belt 20, the outer diameters on the end face sides of the grip portions G1 and G2 are the center portions 11 and 21 of the grip portions G1 and G2. When the recording material S passes through the nip portion N, the grip portion G1, G2 has a maximum outer diameter larger than that of the central portion 11, 21. In addition, even when the heating roller 10 and the pressure belt 20 are separated from each other, the contact between the grip portion G1 of the heating roller 10 and the grip portion G2 of the pressure belt 20 is maintained, and the heating is performed. The driving force can be transmitted from the roller 10 to the pressure belt 20, and the conveying force can be secured.

  Therefore, even if the recording material S having a small friction coefficient is passed through the nip portion N, the conveying force of the recording material S by the heating roller 10 and the pressure belt 20 does not decrease. Slip is prevented between the pressure belt 20 and the speed difference between the recording material S and the heating roller 10 is eliminated, thereby preventing occurrence of image noise. Further, since it is not necessary to increase the conveying force of the recording material S, it is not necessary to increase the width of the grip portions G1, G2, the width of the fixing device can be reduced, and the nip portion can be downsized. Since it is not necessary to increase the pressure contact force at N, it is not necessary to increase the frame strength of the fixing device to prevent bending, and the frame thickness can be reduced to reduce the weight.

  As described above, the frictional resistance between the heating roller 10 and the pressure belt 20 outside the passing range of the recording material S can be improved, and the image quality is improved by preventing the recording material S from passing through. In addition, the fixing device can be reduced in size and weight.

  Here, as a comparative example, as shown in FIG. 4C, when the outer diameter of the grip portion G10 of the end portion 12A of the heating roller 10A is suddenly increased with respect to the outer diameter of the central portion 11A, the central portion 11A and the end portion Insufficient pressure occurs near the boundary with the portion 12A, and fixing failure occurs.

  Further, the outer diameter of the grip portion G1 provided at both end portions 12 of the heating roller 10 is larger on the end face side than the central portion 11 side, and the grip portions provided at both end portions 22 of the pressure belt 20. Since the outer diameter of G2 is larger on the end face side than on the central portion 21 side, the conveying force of the recording material S by the heating roller 10 and the pressure belt 20 can be further improved, and the image quality can be further improved.

  Further, regarding the grip portions G1 and G2 of at least one of the heating roller 10 and the pressure belt 20, the outer diameters of the grip portions G1 and G2 are continuously increased from the central portions 11 and 21 toward the end surface. Therefore, the conveyance force of the recording material S by the heating roller 10 and the pressure belt 20 can be further improved, and the image quality can be further improved.

  Further, both end portions of the pressing member 5 are located inside the both end portions 22 of the pressure belt 20, and the grip portions G2 of the both end portions 22 of the pressure belt 20 are connected to both end portions 12 of the heating roller 10. Since the grip portion pressing portion 6 that presses toward the grip portion G1 is configured, the pressing member 5 is not only formed with the nip portion N but also with the grip portion G1 of the heating roller 10 and the pressure. It can also be used to increase the frictional resistance with the grip portion G2 of the belt 20.

  In addition, since the grip portions G1 and G2 are made of the elastic materials 16 and 26, the friction coefficient of the grip portions G1 and G2 can be easily increased, and the grip portion G1 is elastically deformed by the grip portions G1 and G2. , G2 can be increased in contact area, and frictional resistance can be improved.

  Further, since the grip portions G1 and G2 have lower hardness than the surface of the central portions 11 and 21, the contact area between the grip portions G1 and G2 is increased by elastic deformation of the grip portions G1 and G2. Can improve the frictional resistance.

  Moreover, since the grip part G1 of the said both ends and the part inside the surface of the said center part 11 are connected integrally, regarding the said heating roller 10, while being able to manufacture easily, durability can be improved.

  In addition, since the grip portion G1 and the inner portion of the central portion 11 are made of the same elastic material 16, the friction coefficient of the grip portion G1 can be easily increased, and other factors can be obtained by elastic deformation of the grip portion G1. The contact area to the grip part G2 can be increased, and the frictional resistance can be improved.

  Further, according to the image forming apparatus having the above configuration, since the fixing device is provided, the image quality can be improved, and the size and weight can be reduced.

(Second Embodiment)
FIG. 6 shows a second embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the second embodiment, the configuration of the heating roller is different.

  As shown in FIG. 6, the heating roller 30 of the second embodiment includes a core metal 35, an elastic material 36, and a release material 37 in order from the inside. The core metal 35 is made of, for example, iron, the elastic material 36 is made of, for example, silicone rubber, and the release material 37 is made of, for example, a fluorine-based resin. The release material 37 is located in the central portion 31.

  That is, the end portion 32 is composed of the core metal 35 and the elastic material 36 in order from the inside. The central portion 31 includes the core bar 35, the elastic material 36, and the release material 37 in order from the inside.

  The grip portion G3 is made of the elastic material 36. The grip portions G3 at the both ends and the portion inside the surface of the central portion 31 are integrally connected, and the grip portion G3 and the portion inside the central portion 31 are made of the same elastic material 36. Become.

  For each of the grip portions G3 at both ends, the outer diameter of the grip portion G3 on the end surface side in the width direction of the heating roller 30 is larger than the outer diameter of the grip portion G3 on the center portion 31 side in the width direction of the heating roller 30. large. Further, the maximum outer diameter of the grip part G3 is larger than the maximum outer diameter of the central part 31.

  The outer diameter of the grip portion G3 continuously increases from the central portion 31 in the width direction of the heating roller 30 toward the end surface in the width direction of the heating roller 30. That is, the outer peripheral surface of the elastic member 36 of the grip portion G3 is formed in an inclined shape.

(Third embodiment)
FIG. 7 shows a third embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the third embodiment, the configuration of the heating roller is different.

  As shown in FIG. 7, the heating roller 40 of the third embodiment includes a cored bar 45, a first elastic member 46a and a second elastic member 46b located outside the cored bar 45, and the first elastic member. And a release material 47 located outside 46a.

  The core metal 45 is made of, for example, iron, the first elastic material 46a and the second elastic material 46b are made of, for example, silicone rubber, and the release material 47 is made of, for example, a fluorine resin.

  The first elastic material 46 a is located at the central portion 41, the second elastic material 46 b is located at the end portion 42, and the release material 47 is located at the central portion 41.

  That is, the end 42 is composed of the cored bar 45 and the second elastic member 46b in order from the inside. The central portion 41 includes the cored bar 45, the first elastic material 46a, and the release material 47 in order from the inside.

  The grip part G4 is made of the second elastic material 46b. The second elastic material 46b of the grip portion G4 at both ends and the first elastic material 46a in the portion inside the surface of the central portion 41 are separate processed bodies.

  For each of the grip portions G4 at both ends, the outer diameter of the grip portion G4 on the end surface side in the width direction of the heating roller 40 is larger than the outer diameter of the grip portion G4 on the center portion 41 side in the width direction of the heating roller 40. large. Further, the maximum outer diameter of the grip portion G4 is larger than the maximum outer diameter of the central portion 41.

  The outer diameter of the grip portion G4 continuously increases from the central portion 41 in the width direction of the heating roller 40 toward the end surface in the width direction of the heating roller 40. That is, the outer peripheral surface of the second elastic member 46b of the grip part G4 is formed in an inclined shape.

(Fourth embodiment)
FIG. 8 shows a fourth embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the fourth embodiment, the configuration of the heating roller is different.

  As shown in FIG. 8, the heating roller 50 of the fourth embodiment includes a cored bar 55, a first elastic member 56a and a second elastic member 56b located outside the cored bar 55, and the first elastic member. And a release material 57 located outside 56a.

  The core metal 55 is made of, for example, iron, the first elastic member 56a is made of, for example, silicone rubber, the second elastic member 56b is made of, for example, a silicone sponge as a heat-resistant foam, and the release member 57 is For example, it consists of fluorine resin.

  The first elastic material 56 a is located at the central portion 51, the second elastic material 56 b is located at the end portion 52, and the release material 57 is located at the central portion 51.

  That is, the end 52 is composed of the core metal 55 and the second elastic member 56b in order from the inside. The central portion 51 includes the core metal 55, the first elastic material 56 a, and the release material 57 in order from the inside.

  The grip part G5 is made of the second elastic material 56b. The second elastic material 56b of the grip portion G5 at both ends and the first elastic material 56a in the portion inside the surface of the central portion 51 are separate processed bodies.

  Since the grip portion G5 is made of a heat-resistant foam, the grip portion G5 can be made flexible, and the contact area to other grip portions can be increased by elastic deformation of the grip portion G5, thereby improving the frictional resistance. The second elastic material 56b may be a fluororubber foam.

  For each of the grip portions G5 at both ends, the outer diameter of the grip portion G5 on the end surface side in the width direction of the heating roller 50 is larger than the outer diameter of the grip portion G5 on the center portion 51 side in the width direction of the heating roller 50. large. Further, the maximum outer diameter of the grip portion G5 is larger than the maximum outer diameter of the central portion 51.

  The outer diameter of the grip portion G5 continuously increases from the central portion 51 in the width direction of the heating roller 50 toward the end surface in the width direction of the heating roller 50. That is, the outer peripheral surface of the second elastic member 56b of the grip portion G5 is formed in an inclined shape.

(Fifth embodiment)
FIG. 9 shows a fifth embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the fifth embodiment, the configuration of the heating roller is different.

  As shown in FIG. 9, the heating roller 60 of the fifth embodiment includes a core metal 65, an elastic material 66, and a release material 67 in order from the inside.

  The core metal 65 is made of, for example, iron, the elastic material 66 is made of, for example, silicone rubber, and the release material 67 is made of, for example, fluorine resin.

  The surface of the release material 67 is formed smoothly at the central portion 61 and is formed to be uneven at the end portion 62.

  That is, the end 62 is composed of the concave and convex portions of the core metal 65, the elastic material 66, and the release material 67 in order from the inside. The central portion 61 is composed of smooth portions of the core metal 65, the elastic material 66, and the release material 67 in order from the inside.

  The grip part G <b> 6 is composed of an uneven part of the release material 67. As described above, since the surface of the grip part G6 is formed in an uneven shape, it is not necessary to use another member having a different material from that of the surface of the central part 61 for the grip part G6, thereby reducing the number of parts. it can.

  The uneven shape on the surface of the grip part G6 may be formed by transferring a mold or may be formed by post-processing.

  For each of the grip portions G6 at both ends, the outer diameter of the grip portion G6 on the end surface side in the width direction of the heating roller 60 is larger than the outer diameter of the grip portion G6 on the center portion 61 side in the width direction of the heating roller 60. large. Further, the maximum outer diameter of the grip portion G6 is larger than the maximum outer diameter of the central portion 61.

  The outer diameter of the grip portion G6 continuously increases from the central portion 61 in the width direction of the heating roller 60 toward the end surface in the width direction of the heating roller 60. In this way, when the grip portion G6 is formed in a concavo-convex shape, the outer diameter at the apex of the convex portion is the outer diameter of the grip portion G6.

(Sixth embodiment)
FIG. 10 shows a sixth embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the sixth embodiment, the configuration of the heating roller is different.

  As shown in FIG. 10, the heating roller 70 of the sixth embodiment includes a core metal 75, an elastic material 76, and a release material 77 in order from the inside.

  The core metal 75 is made of, for example, iron, the elastic material 76 is made of, for example, silicone rubber, and the release material 77 is made of, for example, fluorine resin.

  The surface of the release material 77 is formed smoothly at the central portion 71, and the fiber portion 78 is provided at the end portion 72. This fiber part 78 consists of an aramid fiber, for example.

  That is, the end portion 72 includes the core metal 75, the elastic material 76, the release material 77, and the fiber portion 78 in order from the inside. The central portion 71 includes the core metal 75, the elastic material 76, and the release material 77 in order from the inside. That is, the grip part G7 is composed of the fiber part 78, and the surface of the grip part G7 is formed in an uneven shape.

  For each of the grip portions G7 at both ends, the outer diameter of the grip portion G7 on the end surface side in the width direction of the heating roller 70 is larger than the outer diameter of the grip portion G7 on the center portion 71 side in the width direction of the heating roller 70. large. Further, the maximum outer diameter of the grip portion G7 is larger than the maximum outer diameter of the central portion 71.

  The outer diameter of the grip portion G7 increases continuously from the central portion 71 in the width direction of the heating roller 70 toward the end surface in the width direction of the heating roller 70. In addition, when the grip part G7 is formed in a concavo-convex shape in this way, the outer diameter at the apex of the convex part is taken as the outer diameter of the grip part G7.

(Seventh embodiment)
FIG. 11 shows a seventh embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the seventh embodiment, the configuration of the pressure belt is different.

  As shown in FIG. 11, the pressure belt 80 includes a base material 85, an elastic material 86, and a release material 87 in order from the inside. The base material 85 is made of polyimide, for example, the elastic material 86 is made of silicone rubber, for example, and the release material 87 is made of fluorine resin, for example.

  The elastic material 86 has a recess in a portion corresponding to the central portion 81, and the release material 87 is located in the recess.

  That is, the end 82 is composed of the base material 85 and the elastic material 86 in order from the inside. The central portion 81 includes the base material 85, the elastic material 86, and the release material 87 in order from the inside.

  The grip portion G8 is made of the elastic material 86. The grip portion G8 has a lower hardness than the surface hardness of the central portion 81. The grip portions G8 at the both ends and the portion inside the surface of the central portion 81 are integrally connected, and the grip portion G8 and the portion inside the central portion 81 are made of the same elastic material 86. Become.

  For each of the grip portions G8 at both ends, the outer diameter of the grip portion G8 on the end surface side in the width direction of the pressure belt 80 is the outer diameter of the grip portion G8 on the center portion 81 side in the width direction of the pressure belt 80. Bigger than. Further, the maximum outer diameter of the grip part G8 is larger than the maximum outer diameter of the central part 81.

  The outer diameter of the grip portion G8 continuously increases from the central portion 81 in the width direction of the pressure belt 80 toward the end surface in the width direction of the pressure belt 80. That is, the outer peripheral surface of the elastic member 86 of the grip portion G8 is formed in an inclined shape.

(Eighth embodiment)
FIG. 12 shows an eighth embodiment of the fixing device of the present invention. The difference from the first embodiment (FIG. 4) will be described. In the eighth embodiment, the configuration of the pressure belt is different.

  As shown in FIG. 12, the pressure belt 90 of the eighth embodiment includes a base material 95, an elastic material 96, and a release material 97 in order from the inside. The base material 95 is made of, for example, polyimide, the elastic material 96 is made of, for example, silicone rubber, and the release material 97 is made of, for example, fluorine-based resin. The release material 97 is located in the central portion 91.

  That is, the end 92 is composed of the base material 95 and the elastic material 96 in order from the inside. The central portion 91 includes the base material 95, the elastic material 96, and the release material 97 in order from the inside.

  The grip portion G9 is made of the elastic material 96. The grip portion G9 at both ends and the portion inside the center portion 91 are integrally connected, and the grip portion G9 and the inside portion of the center portion 91 are made of the same elastic material 96. Become.

  For each of the grip portions G9 at both ends, the outer diameter of the grip portion G9 on the end surface side in the width direction of the pressure belt 90 is the outer diameter of the grip portion G9 on the center portion 91 side in the width direction of the pressure belt 90. Bigger than. Further, the maximum outer diameter of the grip portion G9 is larger than the maximum outer diameter of the central portion 91.

  The outer diameter of the grip portion G9 continuously increases from the central portion 91 in the pressure belt 90 width direction toward the end surface in the pressure belt 90 width direction. That is, the outer peripheral surface of the elastic member 96 of the grip portion G9 is formed in an inclined shape.

(Example)
Next, [Table 2] shows the relationship between the shape and quality of the heating roller and the pressure belt.

[Table 2]

  Here, as a structure of a heating roller and a pressure belt, what is shown to the said 1st Embodiment (FIG. 4B, FIG. 5) is used. As the dimensions of the heating roller, the width of the central part is 240 mm, the outer diameter of the central part is 26 mm, and the width of the end part is 15 mm. As the dimensions of the pressure belt, the width of the central portion is 230 mm, the outer diameter of the central portion is 30 mm, and the width of the end portion is 15 mm.

  In “the shape of the grip part”, “continuously large” means that the shape of the grip part is the shape shown in FIG. 4B or FIG. 5, and “abruptly large” means that the shape of the grip part is that shown in FIG. The “straight” means a shape in which the outer diameter of the grip portion is the same as the outer diameter of the central portion.

  The “outer diameter difference” is a value obtained by subtracting the maximum outer diameter of the central portion from the maximum outer diameter of the grip portion.

  In “Quality”, “○” indicates “no paper feeding and no noise”, “△” indicates “no paper feeding and no noise”, and “×” indicates “no paper feeding” “Noisy”. “○” and “△” indicate no problem.

  In “Fixability” of “Quality”, “○” indicates “Fixability is good”, “△” indicates “Fixability is weak”, and “X” indicates “Fixability is poor”. Show. “○” and “△” indicate no problem.

  As can be seen from [Table 2], if the shape of the grip portion of the heating roller or pressure belt is continuously large, there is no problem in the paper passing property and fixing property, and the grip portion of the heating roller and pressure belt. If the shape is continuously large, the paper passing property and the fixing property are improved. In addition, even if the shape of the grip portion is continuously large, if the difference in outer diameter is large, a problem occurs in the fixing property.

  In the first embodiment to the eighth embodiment, as a method for manufacturing the heating roller or the pressure belt, a rubber as an elastic material at a central portion and a rubber as an elastic material at a grip portion are cast. After forming or coating by a coating method such as blade, spraying or dipping, a release material as a surface layer may be covered, or a release material as a surface layer may be laminated at the same time only at the central portion during forming. Alternatively, there is a method in which only the grip portion is formed by extrusion molding or the like and inserted later. Alternatively, a method may be used in which rubber is molded only on the grip portion by spraying or the like. Alternatively, the releasable member as the surface layer at the end may be removed, and the rubber as the intermediate layer may be exposed on the surface.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the grip portion may be provided on at least one end of each of the heating roller and the pressure belt.

  Further, regarding the grip portion of at least one of the heating roller or the pressure belt, the outer diameter of the grip portion may be larger on the end face side than on the central portion side.

  Further, the outer diameter of the grip portion may be increased stepwise from the central portion toward the end surface, and the conveyance force of the recording material by the heating roller and the pressure belt can be further improved. Image quality can be further improved.

  Further, at least one of the heating roller and the pressure belt may be formed as in the first to eighth embodiments.

  Further, the first rotating body may be a belt in addition to the heating roller 10. The second rotating body may be a roller other than the pressure belt 20. Further, the heater 7 may be disposed outside the heating roller 10. Moreover, you may use electromagnetic induction heating as a heating part which heats the said heating roller 10. FIG.

  The image forming apparatus may be any one of a monochrome / color copying machine, a printer, a FAX, and a complex machine of these.

1 is a simplified configuration diagram showing a first embodiment of an image forming apparatus of the present invention. 1 is a simplified configuration diagram illustrating a first embodiment of a fixing device according to the present invention. It is a front view which shows a heating roller and a pressure belt. It is a front view which shows a heating roller. It is sectional drawing which shows a heating roller. It is a front view which shows the comparative example of a heating roller. It is sectional drawing which shows a pressurization belt. It is sectional drawing of a heating roller while showing 2nd Embodiment of the fixing device of this invention. It is sectional drawing of a heating roller while showing 3rd Embodiment of the fixing device of this invention. It is sectional drawing of a heating roller while showing 4th Embodiment of the fixing device of this invention. It is sectional drawing of a heating roller while showing 5th Embodiment of the fixing device of this invention. It is sectional drawing of a heating roller while showing 6th Embodiment of the fixing device of this invention. FIG. 10 is a sectional view of a pressure belt, showing a fixing device according to a seventh embodiment of the present invention. It is sectional drawing of a pressure belt while showing 8th Embodiment of the fixing device of this invention.

DESCRIPTION OF SYMBOLS 1 Fixing device 2 Image forming device 5 Pressing member 5a Elastic body pad 5b Rigid body pad 6 Grip part pressing part 7 Heater (heating part)
8 Motor (drive unit)
10, 30, 40, 50, 60, 70 Heating roller (first rotating body)
11, 31, 41, 51, 61, 71 Central portion 12, 32, 42, 52, 62, 72 End portion 20, 80, 90 Pressure belt (second rotating body)
21, 81, 91 Central portion 22, 82, 92 End portion G1 to G9 Grip portion N Nip portion S Recording material t Toner

Claims (6)

A first rotating body and a second rotating body that form a nip portion that contacts each other to sandwich the recording material;
A driving unit that rotates the first rotating body and rotates the second rotating body following the rotation of the first rotating body;
The first rotating body and the second rotating body are each provided with a grip portion at least at one end in the width direction of the rotating body corresponding to the outside of the passing range of the recording material,
The outer diameter at the central portion in the width direction of the rotating body corresponding to the passing range of the recording material is constant,
The upper Symbol grip portion of the first rotary body and said second rotary member, the friction coefficient of the surface, is larger than the friction coefficient of the surface of the central portion of the rotary member widthwise, the grip portion The fixing device is characterized in that an outer diameter of the fixing member gradually increases from a central portion side in the width direction of the rotating body toward an end face side in the width direction of the rotating body. The fixing device according to claim 1,
The fixing device according to claim 1, wherein an outer peripheral surface of the grip portion on a central portion side in the width direction of the rotating body and an outer peripheral surface of the central portion in the width direction of the rotating body are configured continuously. The fixing device according to claim 1 or 2 ,
The grip portion is provided at both ends of the first rotating body ,
The grip portion, a fixing device, characterized in that are provided at both ends of the second rotating body. The fixing device according to any one of claims 1 to 3 ,
The fixing device according to claim 1, wherein an outer diameter of the grip portion of the at least one rotating body increases stepwise from a central portion in the rotating body width direction toward an end surface in the rotating body width direction. The fixing device according to any one of claims 1 to 3 ,
The fixing device according to claim 1, wherein an outer diameter of the grip portion of the at least one rotating body is continuously increased from a central portion in the rotating body width direction toward an end surface in the rotating body width direction. An image forming apparatus comprising the fixing device according to any one of claims 1 5.

Images