JP6792331B2 - Fixing device and image forming device - Google Patents

Description

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

In the image forming apparatus, the medium fed from the paper feeding unit is sent to the transfer unit that secondarily transfers the toner image formed by the developing device to the medium. After the toner image is transferred to the medium at the transfer unit, the toner on the medium is melt-fixed at the fixing unit (fixing device). The medium on which the toner is fixed at the fixing portion is discharged from the downstream discharge portion.

The fixing device of the image forming apparatus described in Patent Document 1 is a belt nip type fixing device, and as a pair of members forming the nip portion, an endless fixing belt and an elastic roller (pressurizing roller) are used. Be prepared. This fixing device has a fixing member arranged on the inner peripheral surface side of the fixing belt. This fixing member receives a load by an elastic roller at the nip portion.

Japanese Unexamined Patent Publication No. 2001-42670

However, in the conventional technique described in Patent Document 1, the fixing belt and the fixing member come into close contact with each other when the belt is not used for a long period of time or when a cold start is performed after a certain period of time has passed from the stopped state. The torque at the start of driving the belt increases.

An object of the present invention is to suppress an increase in torque at the start of driving of a fixing belt in a belt nip type fixing device.

The present invention is a fixing device in which a medium on which a toner image is formed is heated and pressure-welded by a pair of rotating bodies to fix the toner image on the medium. This fixing device includes a tubular fixing belt which is one of a pair of rotating bodies, a pressure roller which is the other of the pair of rotating bodies and presses a medium against the outer peripheral surface of the fixing belt, and the inside of the fixing belt. A contact member having a contact portion that contacts the inner peripheral surface of the fixing belt. A plurality of convex shapes protruding from the reference surface toward the pressure roller side are formed at the contact portion of the contact member.

In this fixing device, since a plurality of convex shapes protruding from the reference surface are formed at the contact portion of the contact member, the contact area between the inner peripheral surface of the fixing belt and the contact member is reduced, and the device is stopped. At times, the force with which the fixing belt and the contact member come into close contact with each other can be weakened. Therefore, it is possible to suppress an increase in torque at the start of driving the fixing belt. Further, since the resistance when the fixing belt moves can be reduced without arranging another member such as a sliding sheet between the contact member and the fixing belt, the increase in cost can be suppressed while suppressing the increase in cost. The increase in torque can be suppressed.

The length of contact between one of the plurality of convex shapes and the inner peripheral surface of the fixing belt can be 0.55 mm or more in the width direction orthogonal to the moving direction of the fixing belt. The pitch of a plurality of adjacent convex shapes can be 1.1 mm or more. When such a plurality of convex shapes are formed, the force with which the fixing belt and the contact member are brought into close contact with each other can be suitably weakened, and an increase in torque at the start of driving of the fixing belt can be suppressed. Further, in the state where the fixing belt is driven, the load by the pressurizing roller can be made uniform, and the generation of a portion where the load is difficult to be applied can be suppressed at the contact portion.

The plurality of convex shapes may be arranged in a grid pattern along a width direction orthogonal to the moving direction of the fixing belt and arranged side by side in a direction intersecting the width direction. At least one of the plurality of convex shapes is arranged in the moving direction of the fixing belt. The plurality of convex shapes may be arranged without gaps over the entire width in the width direction when viewed from the moving direction of the fixing belt. This prevents the formation of a region that does not come into contact with the fixing belt. Therefore, in the contact member, the load by the pressurizing roller can be made uniform, and the generation of a portion where the load is difficult to be applied can be suppressed in the entire length of the contact portion.

The convex shape may have a band shape and extend in the width direction orthogonal to the moving direction of the fixing belt. The length of contact between one of the plurality of convex shapes and the inner peripheral surface of the fixing belt may be 0.55 mm or more in the moving direction of the fixing belt.

The convex shape may have a configuration having an inclined portion arranged outside in the width direction. The inclined portion may be inclined so as to be located from the upstream side to the downstream side in the moving direction of the fixing belt toward the outside in the width direction. As a result, the side end portion of the fixing belt can be smoothly moved.

The pitch of the plurality of adjacent convex shapes can be 1.1 mm or more in the moving direction of the fixing belt.

The contact portion may include a lubricant holding convex portion for holding the lubricant between the reference surface and the inner peripheral surface of the fixing belt. The lubricant holding convex portion may extend in the moving direction of the fixing belt and project from the reference surface toward the pressure roller side. The lubricant holding protrusions may be arranged on both sides in the width direction orthogonal to the moving direction of the fixing belt. As a result, it is possible to prevent the lubricant from flowing out from the protrusion for holding the lubricant.

The protrusion for holding the lubricant has a band shape, and the protrusion for holding the lubricant is outside the image formation region, which is a region where the toner image is formed on the medium, in the width direction, and is formed by a pressure roller. It is preferably formed in the nip load region, which is the region for receiving the load. Since the lubricant holding convex portion is arranged in the nip load region, the lubricant holding convex portion and the inner peripheral surface of the fixing belt can be reliably brought into contact with each other. Further, since the protrusion for holding the lubricant is arranged outside the image forming region, the lubricant can be held at a position corresponding to the image forming region.

The contact portion may have a structure having a base material and a surface layer formed on the base material. At least a portion of the base material, aluminum, stainless steel, liquid crystal polymer, may contain a polyphenylene sulfide or we selected one material. At least a part of the surface layer may contain at least one selected from polytetrafluoroethylene, perfluoroalkoxy alkane resin and modified products thereof. In such a case, the force with which the fixing belt and the contact member are brought into close contact with each other can be suitably weakened when the device is stopped. Therefore, it is possible to reliably suppress the increase in torque at the start of driving the fixing belt.

The contact portion is made of a plate material containing at least aluminum, and the thickness of the contact portion can be 0.2 mm or more and 0.5 mm or less. The plurality of convex shapes of the abutting portion can be formed by press working, etching processing, or laser processing.

The contact portion is made of a plate material containing at least stainless steel, and the thickness of the contact portion can be 0.1 mm or more and 0.3 mm or less. The plurality of convex shapes of the abutting portion can be formed by press working, etching processing, or laser processing.

At least a portion of the abutment can be molded from a material containing a liquid crystal polymer or polyphenylene sulfide. The plurality of convex shapes of the abutting portion can be formed by injection molding, etching processing, or laser processing.

The fixing device is arranged on the upstream side in the moving direction of the fixing belt with respect to the contact member, and is located on the lubricant supply unit that supplies the lubricant to the contact portion of the contact member and the downstream side in the moving direction of the fixing belt. A film of lubricant that is arranged and comes into contact with the inner peripheral surface of the fixing belt to regulate the shape when the fixing belt is rotating and moves, and also adheres to the inner peripheral surface of the fixing belt and moves downstream from the contact member. It is provided with a film thickness regulating section that regulates the thickness.

In this fixing device, the lubricant is supplied from the lubricant supply unit arranged on the upstream side of the contact member in the moving direction of the fixing belt. This lubricant adheres to the inner peripheral surface of the fixing belt, moves together with the fixing belt, and is supplied to the contact portion of the contact member. As a result, the lubricant is present between the contact portion of the contact member and the inner peripheral surface of the fixing belt, and an increase in torque at the start of driving of the fixing belt can be suppressed.

Further, since this fixing device is configured to include a film thickness regulating portion arranged on the downstream side in the moving direction of the fixing belt, the lubricant that adheres to the inner peripheral surface of the fixing belt and moves downstream from the contact member. The film thickness is regulated. As a result, the amount of lubricant that moves downstream from the film thickness regulating portion can be reduced, and contamination by the lubricant can be suppressed inside the fixing belt. Similarly, the wear debris generated by the friction between the fixing belt and the contact member is suppressed from moving downstream by the film thickness regulating portion. As a result, it is possible to reduce the amount of wear debris that moves downstream from the film thickness regulating portion, and it is possible to suppress contamination by the wear debris inside the fixing belt. Further, since the film thickness regulating portion abuts on the inner peripheral surface of the fixing belt, the shape of the rotating fixing belt is restricted. As a result, the rotational runout of the fixing belt is suppressed. As a result, it is possible to prevent the fixing belt from unexpectedly hitting another member (for example, a separating member) arranged on the outer peripheral surface side of the fixing belt. The rotational runout is a displacement in the thickness direction of the fixing belt that occurs when the fixing belt is rotationally moved.

Further, the film thickness regulating portion may have a configuration having a protruding portion protruding outward in the radial direction of the fixing belt. The projecting portion projects outward from the nip surface formed along the surfaces where the outer peripheral surfaces of the pair of rotating bodies come into contact with each other in the radial direction of the fixing belt. According to this configuration, the film thickness regulating portion is arranged outside the contact portion of the contact member in the radial direction of the fixing belt. Since the film thickness regulating portion adheres more stably to the inner peripheral surface of the fixing belt, the lubricant and wear debris adhering to the inner peripheral surface of the fixing belt are surely regulated by the film thickness regulating portion. .. Therefore, contamination by the lubricant and abrasion powder is suppressed inside the fixing belt. Further, since the film thickness regulating portion and the fixing belt are surely adhered to each other, the displacement of the fixing belt in the thickness direction is suppressed, and the rotational runout of the fixing belt is preferably suppressed. Further, since the film thickness regulating portion is arranged outside the nip surface in the radial direction of the fixing belt, the fixing belt can be brought close to other members arranged on the outer peripheral surface side of the fixing belt.

The fixing device may further include a separating member for separating the medium adhering to the outer peripheral surface of the fixing belt. The separating member may be provided on the outlet side of the nip portion where the medium is sandwiched by the pair of rotating bodies. The protrusion may be arranged between the abutting member and the separating member in the moving direction of the fixing belt. As a result, the separating member is arranged downstream from the contact point between the protruding portion and the fixing belt. Therefore, the separating member can be arranged close to the fixing belt after passing through the protruding portion and suppressing the rotational runout.

The film thickness regulating portion has a guide surface that abuts on the inner peripheral surface of the fixing belt. The guide surface is curved along the circumferential direction of the fixing belt. As a result, the guide surface is brought into contact with the inner peripheral surface of the fixing belt, so that the fixing belt is guided and conveyed along the guide surface. Therefore, the shape of the fixing belt can be stabilized, and the rotational runout of the fixing belt can be suitably suppressed.

The film thickness regulating portion is formed at the upstream end of the guide surface in the moving direction of the fixing belt, and is in contact with the edge portion that scrapes off the lubricant adhering to the inner peripheral surface of the fixing belt and the moving direction of the fixing belt. It may be configured to have a lubricant accommodating portion which is on the downstream side of the contact member, is arranged on the upstream side of the edge portion, and accommodates the lubricant scraped off by the edge portion. According to this configuration, the lubricant adhering to the inner peripheral surface of the fixing belt is scraped off by the edge portion formed at the end portion of the guide surface. The lubricant scraped off by the edge portion is stored in the lubricant accommodating portion and recovered.

The edge portion may have an inclined surface that is inclined with respect to a tangent line that is in contact with the inner peripheral surface of the fixing belt. The inclined surface is a surface on the rotation center side of the fixing belt at the edge portion, and may be configured to be inclined with respect to a tangent line in contact with the inner peripheral surface of the fixing belt. As a result, the excess lubricant adhering to the inner peripheral surface of the fixing belt moves along the slope of the edge portion and is suitably separated from the inner peripheral surface of the fixing belt.

The fixing device may further include a separating member for separating the medium adhering to the outer peripheral surface of the fixing belt. The separating member may be provided on the outlet side of the nip portion where the medium is sandwiched by the pair of rotating bodies. The edge portion may be arranged between the contact member and the separating member in the moving direction of the fixing belt. As a result, the separating member is arranged downstream from the contact point between the edge portion and the fixing belt. Therefore, the separating member can be arranged close to the fixing belt after passing through the edge portion and suppressing the rotational runout.

The film thickness regulating portion may have a structure having a non-woven fabric that comes into contact with the inner peripheral surface of the fixing belt. When the non-woven fabric is provided in the film thickness regulating portion in this way, the lubricant adhering to the inner peripheral surface of the fixing belt is wiped off by the non-woven fabric, and the adhering amount is reduced.

The fixing belt may have a resin base material, and the lubricant supply unit may be configured to supply a black lubricant. As a result, the black lubricant can be applied to the inner peripheral surface of the fixing belt, and the radiant heat from the heat source arranged on the inner peripheral surface side of the fixing belt can be efficiently absorbed. Therefore, the fixing belt is efficiently heated.

According to the present invention, in the belt nip type fixing device, it is possible to suppress an increase in torque at the start of driving the fixing belt.

It is a schematic block diagram of the image forming apparatus provided with the fixing apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the fixing device of the belt nip type. It is sectional drawing which shows the fixing nip part enlarged. It is an enlarged perspective view which shows the contact part of the contact member which concerns on 1st Embodiment. It is a top view which shows the convex shape of the contact part enlarged. It is an enlarged perspective view which shows the contact part of the contact member which concerns on 2nd Embodiment. It is a top view which shows the convex shape of the contact part enlarged. It is a graph which shows the torque at the start of driving of a fixing belt. It is sectional drawing which shows the fixing apparatus which concerns on 3rd Embodiment. It is sectional drawing which shows the film thickness regulation part which concerns on the modification by enlargement. It is sectional drawing which shows the fixing apparatus which concerns on 4th Embodiment. It is sectional drawing which shows the edge part of the film thickness regulation member enlarged.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same parts or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

The image forming apparatus 1 according to the first embodiment is an apparatus for forming a color image using each color of magenta, yellow, cyan, and black. As shown in FIG. 1, the image forming apparatus 1 includes a medium conveying unit 10 for conveying the medium P, a developing apparatus 20 for developing an electrostatic latent image, and a transfer unit 30 for secondary transfer of a toner image to the medium P. A photoconductor drum 40, which is an electrostatic latent image carrier on which an image is formed on the peripheral surface, and a fixing device 50, which fixes a toner image on the medium P, are provided.

The medium transport unit 10 accommodates the medium P as a recording medium on which an image is formed, and transports the medium P on the transport path R1. The medium P is stacked and housed in the cassette K. The medium transfer unit 10 causes the medium P to reach the secondary transfer area R2 via the transfer path R1 at the timing when the toner image transferred to the medium P reaches the secondary transfer area R2.

Four developing devices 20 are provided for each color. Each developing device 20 includes a developing roller 21 that supports the toner on the photoconductor drum 40. In the developing apparatus 20, after the toner and the carrier are mixed and stirred to be sufficiently charged, the developing agent produced by the mixing of the toner and the carrier is supported on the developing roller 21. Then, when the developer is conveyed to the region facing the photoconductor drum 40 by the rotation of the developing roller 21, the toner of the developer carried on the developing roller 21 is formed on the peripheral surface of the photoconductor drum 40. It moves to the electrostatic latent image and the electrostatic latent image is developed.

The transfer unit 30 transfers the toner image formed by the developing device 20 to the secondary transfer region R2 for secondary transfer to the medium P. The transfer unit 30 includes a transfer belt 31, suspension rollers 31a, 31b, 31c, 31d for suspending the transfer belt 31, a primary transfer roller 32 for sandwiching the transfer belt 31 together with the photoconductor drum 40, and a transfer belt together with the suspension roller 31d. It includes a secondary transfer roller 33 that sandwiches the 31.

The transfer belt 31 is an endless belt that circulates and moves by suspension rollers 31a, 31b, 31c, and 31d. The primary transfer roller 32 is provided so as to press the photoconductor drum 40 from the inner peripheral side of the transfer belt 31. The secondary transfer roller 33 is provided so as to press the suspension roller 31d from the outer peripheral side of the transfer belt 31.

Four photoconductor drums 40 are provided for each color. Each photoconductor drum 40 is provided along the moving direction of the transfer belt 31. A developing device 20, a charging roller 41, an exposure unit 42, and a cleaning unit 43 are provided on the periphery of the photoconductor drum 40.

The charging roller 41 uniformly charges the surface of the photoconductor drum 40 to a predetermined potential. The exposure unit 42 exposes the surface of the photoconductor drum 40 charged by the charging roller 41 according to the image formed on the medium P. As a result, the potential of the portion of the surface of the photoconductor drum 40 exposed by the exposure unit 42 changes, and an electrostatic latent image is formed. The four developing devices 20 develop an electrostatic latent image formed on the photoconductor drum 40 by toner supplied from a toner tank 22 provided opposite to each developing device 20 to generate a toner image. .. Each toner tank 22 is filled with magenta, yellow, cyan, and black toners, respectively. The cleaning unit 43 collects the toner remaining on the photoconductor drum 40 after the toner image formed on the photoconductor drum 40 is first transferred to the transfer belt 31.

The fixing device 50 fixes the toner image secondarily transferred from the transfer belt 31 to the medium P on the medium P. The fixing device 50 includes a fixing belt 51 that heats the medium P and a pressure roller (elastic roller) 52 that presses the fixing belt 51. The fixing belt 51 and the pressure roller 52 are formed in a cylindrical shape. A fixing nip portion 53, which is a contact region, is formed between the fixing belt 51 and the pressure roller 52, and the toner image is melt-fixed to the medium P by passing the medium P through the fixing nip portion 53, for example, in the transport direction. Let me.

Further, the image forming apparatus 1 is provided with discharge rollers 71 and 72 for discharging the medium P on which the toner image is fixed by the fixing device 50 to the outside of the device.

Next, the operation of the image forming apparatus 1 will be described. When the image signal of the recorded image is input to the image forming apparatus 1, the control unit of the image forming apparatus 1 makes the surface of the photoconductor drum 40 uniform at a predetermined potential by the charging roller 41 based on the received image signal. To be charged. After that, the surface of the photoconductor drum 40 is irradiated with laser light by the exposure unit 42 to form an electrostatic latent image.

On the other hand, in the developing apparatus 20, the electrostatic latent image is developed to form a toner image. The toner image thus formed is primarily transferred from the photoconductor drum 40 to the transfer belt 31 in the region where the photoconductor drum 40 and the transfer belt 31 face each other. Toner images formed on the four photoconductor drums 40 are sequentially laminated on the transfer belt 31, and one laminated toner image is formed. Then, the laminated toner image is secondarily transferred to the medium P transferred from the medium transfer unit 10 in the secondary transfer region R2 where the suspension roller 31d and the secondary transfer roller 33 face each other.

The medium P on which the laminated toner image is secondarily transferred is conveyed to the fixing device 50. By passing the medium P between the fixing belt 51 and the pressure roller 52 while applying heat and pressure, the laminated toner image is melt-fixed to the medium P. After that, the medium P is discharged to the outside of the image forming apparatus 1 by the discharge rollers 71 and 72.

Here, the fixing device 50 will be described in more detail.

As shown in FIG. 2, the fixing device 50 includes a fixing belt 51, a pressure roller 52, a contact member (fixing member) 54, and a heating source (heater) 55. Further, the fixing device 50 has a separating member 56 that separates the medium P adhering to the outer peripheral surface 51a of the fixing belt 51 from the fixing belt 51. The separating member 56 is arranged downstream of the fixing nip portion 53 in the transport path R3 of the medium P.

As shown in FIGS. 2 and 3, the fixing nip portion 53 is a portion in which the medium P is sandwiched between the fixing belt 51 and the pressure roller 52. The fixing nip portion 53 includes a portion (contact portion) where the outer peripheral surface 51a of the fixing belt 51 and the outer peripheral surface 52a of the pressure roller 52 are closest to each other. The internal pressure in the fixing nip portion 53 is generally 0.049 MPa or more and 0.196 MPa or less (0.5 kgf / cm ² or more, 2.0 kgf / cm ² or more). The internal pressure in the fixing nip portion 53 is the pressure received by the medium P sandwiched between the fixing belt 51 and the pressure roller 52.

The fixing belt 51 is a flexible tubular rotating body, and is formed of, for example, metal. Examples of the metal material used for the fixing belt 51 include stainless steel. Further, the fixing belt 51 may be formed of, for example, a resin.

As shown in FIG. 3, the fixing belt 51 is formed by laminating a plurality of types of materials. The fixing belt 51 has a base material 57, an elastic layer 58 laminated on the base material 57, and a surface layer 59 laminated on the elastic layer 58. The base material 57 is made of a metal material such as stainless steel or nickel. Further, the base material 57 may be formed of, for example, a resin such as polyimide (PI), polyamiimide (PAI), polyetheretherketone (PEEK), or liquid crystal polymer (LCP).

The elastic layer 58 is formed of, for example, rubber. The surface layer 59 is made of a fluororesin. The fluororesin is, for example, at least one selected from polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane resin (PFA), and modified products thereof. The thickness of the base material 57 is, for example, 20 μm or more and 120 μm or less, the thickness of the elastic layer 58 is, for example, 100 μm or 400 μm or less, and the thickness of the surface layer 59 is, for example, 10 μm or more and 50 μm or less.

The pressure roller 52 is a cylindrical rotating body having elasticity, and is formed of, for example, rubber (elastic body). The pressure roller 52 has an elastic layer 61 made of an elastic body and a surface layer 62 formed on the elastic layer 61. A rotating shaft 60 is inserted inside the pressurizing roller 52.

The contact member 54 is arranged inside the fixing belt 51 and receives a pressing load from the pressurizing roller 52. The contact member 54 is urged toward the pressure roller 52 by, for example, a spring member (not shown). The pressure roller 52 may be urged toward the contact member 54. Further, the pressure roller 52 may be urged to the contact member 54 side, and the contact member 54 may be urged to the pressure roller 52 side.

The contact member 54 extends in the axial direction of the tubular fixing belt 51 and penetrates in the axial direction, the support 64 fixed to the structure 63, and the support 64. The fixed sliding member 65 is provided.

The cross sections of the structure 63, the support 64, and the fixed sliding member 65 orthogonal to the longitudinal direction are, for example, U-shaped. The structure 63 has a pair of side walls 63a facing the transport direction (R3) of the medium P, and a main body 63b connecting the ends of the pair of side walls 63a on the pressure roller 52 side. The body portion 63b of the structure 63 forms a plate shape, thickness direction of the main body portion 63b has a rotational center _{O 51} of the fixing belt 51, a straight line L1 connecting the rotation center _{O 52} of the pressing roller 52 extends It may be arranged along the direction in which it is used.

The support 64 has a pair of side walls 64a facing in the transport direction of the medium P, and a main body 64b that connects the ends of the pair of side walls 64a on the pressure roller 52 side. The main body portion 64b of the support body 64 has a plate shape, and the plate thickness direction of the main body portion 64b is arranged along the direction in which the straight line L1 extends. The support 64 is attached to the structure 63 and is arranged so as to cover the pressure roller 52 side of the structure 63. The main body portion 64b of the support 64 covers the main body portion 63b of the structure 63, and the pair of side walls 64a of the support 64 covers the pair of side walls 63a of the structure 63, respectively.

The fixed sliding member 65 has a pair of side walls 65a facing in the transport direction of the medium P, and a main body portion (contact portion) 65b for connecting the ends of the pair of side walls 65a on the pressure roller 52 side. .. The main body portion 65b of the fixed sliding member 65 has a plate shape, and the plate thickness direction of the main body portion 65b is arranged along the direction in which the straight line L1 extends. The fixed sliding member 65 is attached to the support 64 and is arranged so as to cover the pressure roller 52 side of the support 64. The main body portion 65b of the fixed sliding member 65 covers the main body portion 64b of the support 64, and the pair of side walls 65a of the fixed sliding member 65 covers the pair of side walls 64a of the support 64, respectively.

The fixed sliding member 65 has a base material and a surface layer formed on the base material. The base material of the fixed sliding member 65 is formed of, for example, a metal material such as aluminum or stainless steel. Further, the fixed sliding member 65 may be formed of a heat-resistant resin such as a liquid crystal polymer (LCP) or polyphenylene sulfide (PPS).

Further, a fluororesin is applied to the surface (surface layer) of the main body portion 65b of the fixed sliding member 65. The fluororesin is, for example, at least one selected from polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane resin (PFA), and modified products thereof.

As shown in FIG. 3, the main body portion 65b of the fixed sliding member 65 of the contact member 54 is a contact portion that abuts on the inner peripheral surface 51b of the fixing belt 51. The pressure roller 52 rotates about an axis by transmitting power from a drive motor (not shown). The outer peripheral surface 52a of the pressure roller 52 is in contact with the outer peripheral surface 51a of the fixing belt 51 at the fixing nip portion 53. The fixing belt 51 rotates about an axis by transmitting the rotational force of the pressure roller 52.

In the fixing nip portion 53, the fixing belt 51 receives a pressing load from the pressure roller 52 and slides in contact with the main body portion 65b of the fixed sliding member 65. The fixing belt 51 forms a flat surface along the main body portion 65b of the fixed sliding member 65 at the fixing nip portion 53. In the fixing nip portion 53, the moving direction Y of the fixing belt 51 coincides with the conveying direction (R3) of the medium P. The nip surface N of the fixing nip portion 53 is a virtual surface sandwiched between the fixing belt 51 and the pressure roller 52.

Here, as shown in FIGS. 3, 4 and 5 (a), the main body portion 65b of the fixed sliding member 65 has a plurality of convex shapes 67 protruding from the reference surface 66 toward the pressure roller 52. It is formed. The reference surface 66 is a surface of the main body 65b on the pressure roller 52 side, and is, for example, a surface orthogonal to the straight line L1. The plurality of convex shapes 67 have, for example, a rectangular shape in a plan view. The plurality of convex shapes 67 have, for example, the same dimensions and the same shape.

In the convex shape 67, the length L X 67 along the width direction X orthogonal to the moving direction Y is, for example, 0.55 _mm or more. Further, the pitch (arrangement interval) P ₆₇ between the convex shapes 67 adjacent to each other in the width direction X is, for example, 1.1 mm or more.

Further, the plurality of convex shapes 67 are arranged side by side at equal intervals in the width direction X to form a row (first row X1, second row X2). The plurality of convex shapes 67 forming a row in the width direction X are arranged at equal intervals in the Y direction. For example, the convex shape 67 of the second row X2 is arranged so as to fill the gap between the plurality of convex shapes 67 of the first row X1. The length L _X 67 of the convex shape 67 is larger than the gap D ₆₇ between the convex shapes 67.

At least one of the plurality of convex shapes 67 is arranged in the moving direction Y of the fixing belt 51. The plurality of convex shapes 67 are arranged without gaps over the entire width in the width direction X when viewed from the moving direction Y of the fixing belt 51. That is, it is prevented that a region that does not come into contact with the fixing belt 51 is formed over the entire length of the main body portion 65b in the transport direction of the medium P. Therefore, in the fixed sliding member 65, the load by the pressure roller 52 can be made uniform, and the generation of a portion in the fixing nip portion 53 where no load is applied can be suppressed.

The height H ₆₇ of the plurality of convex shapes 67 is, for example, 5 μm or more and 30 μm or less. The height H ₆₇ of the plurality of convex shapes 67 is the difference in height from the reference surface 66 to the plane of the top of the convex shapes 67.

When the fixed sliding member 65 having a plurality of convex shapes 67 is formed of a metal material, the plurality of convex shapes 67 can be formed by, for example, press working, etching processing, or laser processing. When the fixed sliding member 65 having a plurality of convex shapes 67 is formed of a resin material, the plurality of convex shapes 67 can be formed by, for example, injection molding, etching processing, or laser processing. .. By corroding the surface of the substance by the action of chemicals and performing etching processing, the surface of the abutting portion can be textured to form a convex shape 67. Further, etching processing can be performed to form a geometric pattern on the surface of the abutting portion to form a plurality of convex shapes 67.

Further, when a plurality of convex shapes 67 are formed by laser processing, a laser engraving machine that irradiates lasers from a plurality of directions can be used. Thereby, a plurality of convex shapes 67 having a complicated shape can be formed.

Further, when the base material of the fixed sliding member 65 is formed of an aluminum plate material, if the thickness of the base material is, for example, 0.2 mm or more and 0.5 mm or less, the influence of springback during press working is suppressed. be able to. Thereby, a plurality of convex shapes 67 can be clearly formed.

Further, when the base material of the fixed sliding member 65 is formed of a stainless steel plate material, if the thickness of the base material is, for example, 0.1 mm or more and 0.3 mm or less, the influence of springback during press working is suppressed. be able to. Thereby, a plurality of convex shapes 67 can be clearly formed.

In such a fixing device 50, since a plurality of convex shapes 67 protruding from the reference surface 66 are formed at the contact portion which is the main body portion 65b of the fixed sliding member 65, the inner peripheral surface 51b of the fixing belt 51 is formed. And the contact area of the fixed sliding member 65 with the main body 65b can be reduced. As a result, an increase in torque at the start of driving the fixing belt 51 is suppressed. Further, since the friction between the fixed sliding member 65 and the fixing belt 51 is reduced, energy consumption when driving the fixing belt 51 can be suppressed. Further, the sliding resistance can be reduced without arranging another member such as a sliding sheet between the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51. Therefore, it is possible to simplify the structure of the device, suppress the increase in cost, and suppress the increase in torque at the start of driving the fixing belt 51.

Further, since a plurality of convex shapes 67 protruding from the reference surface 66 are formed in the main body portion 65b of the fixed sliding member 65, lubrication is performed on the reference surface (non-contact portion) 66 around the plurality of convex shapes 67. The agent can be retained. As a result, the fixing belt 51 is preferably slid, the fixing belt 51 can be prevented from deteriorating over time, and the quality of the fixing device 50 can be maintained for a long period of time.

Further, in one convex shape 67 of the fixed sliding member 65, the length of contact with the inner peripheral surface 51b of the fixing belt 51 is 0.55 mm or more in the width direction X. Further, the pitch P ₆₇ of the plurality of adjacent convex shapes ₆₇ is 1.1 mm or more. In this fixing device 50, since the plurality of convex shapes 67 as described above are formed, the adhesive force between the fixing belt 51 and the fixed sliding member 65 is suitably weakened, and the torque at the start of driving the fixing belt 51 is reduced. Increase is suppressed. Further, in the fixed sliding member 65, the load by the pressurizing roller 52 can be made uniform while the fixing belt 51 is being driven, and the generation of a portion in the fixing nip portion 53 where no load is applied is suppressed. be able to. In the configuration having a plurality of convex shapes 67, the internal pressure in the fixing nip portion 53 is 0.098 Mpa or less.

Next, a first modification of the convex shape will be described with reference to FIG. 5 (b). The convex shape is not limited to the rectangular shape, and may be a convex shape 68 forming a rhombus in a plan view.

Of the two diagonals of the rhombus convex 68, the longer diagonal L2 is, for example, arranged along the moving direction Y. Of the two diagonals of the convex 68, the shorter diagonal L3 is, for example. , Arranged in the width direction X.

In the convex shape 68, the length L _X68 along the width direction X orthogonal to the moving direction Y is, for example, 0.55 mm or more. Further, the pitch P ₆₈ between the convex shapes 68 adjacent to each other in the width direction X is, for example, 1.1 mm or more. The length L _{X 68} of the convex shape 68 is larger than the gap D ₆₈ between the convex shapes 68.

Next, a second modification of the convex shape will be described with reference to FIG. 5 (c). The convex shape 69 according to the second modification may be a convex shape forming a circle in a plan view.

The plurality of convex shapes 69 form a row side by side in the width direction (first direction) X, and the plurality of convex shapes 69 forming a row along the width direction X form a moving direction (second direction) Y. Multiple columns are arranged in. Further, the plurality of convex shapes 69 in rows adjacent to each other in the width direction X are arranged at different positions in the width direction X. The plurality of convex shapes 69 are arranged in a grid pattern. The direction in which the convex shapes 69 form a row is not limited to the width direction X and the moving direction Y, and may be other directions. Further, the first direction and the second direction of forming the grid pattern may be orthogonal directions or intersecting directions so as to be inclined at a predetermined angle.

The diameter L _X 69 of the convex shape 69 is, for example, 0.55 mm or more. Further, the pitch P ₆₉ between the convex shapes 69 adjacent to each other in the width direction X is, for example, 1.1 mm or more. The diameter L _X 69 of the convex shape 69 is larger than the gap D ₆₉ between the convex shapes 69.

Next, with reference to FIG. 6, the convex shape of the fixed sliding member of the contact member according to the second embodiment will be described. The main body (contact portion) 81b of the fixed sliding member 81 of the second embodiment is formed with strip-shaped convex shapes 82 and 83 as a plurality of convex shapes. A plurality of convex shapes 82 extend in the width direction X and are spaced apart from each other in the moving direction Y. Further, the convex shape 83 extends along the moving direction Y on both sides of the width direction X.

The convex shape 83 is arranged outside the convex shape 82 in the width direction X. In the fixing device 50, the lubricant is held between the main body portion 81b of the fixed sliding member 81 and the inner peripheral surface 51b of the fixing belt 51. The convex shape 83 functions as a lubricant holding convex portion for holding the lubricant existing between the main body portion 81b of the fixed sliding member 81 and the inner peripheral surface 51b of the fixing belt 51. The convex shape 83 is arranged outside the image forming region of the medium P in the width direction X and inside the nip load region that receives the load from the pressurizing roller 52. The image forming region of the medium P is a region in which the toner image is formed in the medium P. The nip load region is a region where the fixing belt 51 and the pressure roller 52 are in contact with each other.

The width _LY82 of the convex shape 82 is, for example, 0.55 mm or more. Further, the pitch P ₈₂ between the convex shapes 82 adjacent to each other in the moving direction Y is, for example, 1.1 mm or more. The width of the convex shape 83 is, for example, _{equal to} or _larger than the width _LY82 of the convex shape 82.

When the band-shaped convex shapes 82 are formed on both sides in the width direction X in this way, the width direction X of the lubricant between the main body portion 65b of the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51. Movement is restricted in. As a result, in the fixing nip portion 53, leakage of the lubricant from the outside in the width direction X is prevented.

Next, a modified example of the strip-shaped convex shape will be described with reference to FIG. 7. The band-shaped convex shapes 85 to 87 shown in FIGS. 7 (a) to 7 (c) are modified examples of the band-shaped convex shape 82 shown in FIG. 6 (third modified example to fifth modified example). Is. In FIG. 7, among the band-shaped convex shapes 85 to 87, from the central portion in the longitudinal direction to one end portion is illustrated.

As shown in FIG. 7A, the strip-shaped convex shape 85 according to the third modification is inclined at a predetermined inclination angle with respect to the straight line extending in the width direction X of the medium P. The band-shaped convex shape 85 is not orthogonal to the moving direction Y. The strip-shaped convex shape 85 is inclined over the entire length in the longitudinal direction. Further, the inclination angle of the strip-shaped convex shape 85 may be constant or different depending on the position in the longitudinal direction.

As shown in FIG. 7B, the strip-shaped convex shape 86 according to the fourth modification has a central portion 86a and an end portion 86b in the longitudinal direction. The central portion 86a has a length of, for example, about 1/3 of the total length in the longitudinal direction of the convex shape 86. The central portion 86a is orthogonal to the moving direction Y. The end portion 86b is an inclined portion inclined with respect to the central portion 86a on both sides of the central portion 86a. As for the end portion 86b, a portion on the central portion 86a side is arranged upstream in the moving direction Y, and a portion outside in the longitudinal direction is arranged downstream in the moving direction Y. The angle at which the end portion 86b and the central portion 86a intersect is, for example, about 5 (deg) or more and 30 (deg) or less.

Further, the strip-shaped convex shape may not include a portion orthogonal to the moving direction Y in the central portion in the longitudinal direction, and may be inclined from the center to both end portions. For example, they may be arranged in a V shape with the center in the longitudinal direction as the apex. Also in this case, the central side is arranged upstream of the moving direction Y, and the outer side in the longitudinal direction is arranged downstream of the moving direction Y.

Further, the strip-shaped convex shape has a portion orthogonal to the moving direction Y in the central portion in the longitudinal direction, and is curved so as to be arranged on both sides thereof on the downstream side of the moving direction Y toward the outside in the longitudinal direction. It may be in the shape of

As shown in FIG. 7C, the strip-shaped convex shape 87 according to the fifth modification may be curved so as to form a waveform. The convex shape 87 has a plurality of curved portions, and curved portions that are curved on opposite sides are alternately arranged in the width direction X. Also in this case, both ends in the longitudinal direction are arranged downstream in the moving direction Y toward the outside.

Next, with reference to FIG. 8, the torque at the start of driving the fixing belt will be described. FIG. 8 is a graph showing the torque at the start of driving the fixing belt 51. In FIG. 8, the horizontal axis shows the load (N) at the fixing nip portion, and the vertical axis shows the torque (Nm) at the start of driving the fixing belt 51.

As the first embodiment, as shown in FIG. 4, a fixing device including a fixed sliding member 65 in which a plurality of rectangular convex shapes 67 are formed is used. As Comparative Example 1, a fixing device provided with a fixed sliding member having a flat surface and no uneven shape was used. In Example 1 and Comparative Example 1, they are the same except for the presence or absence of a convex shape. Then, the maximum value of the torque at the start of driving the fixing belt 51 was measured and graphed.

In Example 1 and Comparative Example 1, the load on the fixing nip portion 53 was changed, and the measurement was performed a plurality of times. In FIG. 8, the measurement result in Example 1 is shown in Graph G1, and the measurement result in Comparative Example 1 is shown in Graph G2. For example, it was found that the torque of Example 1 was reduced by 30% or more with respect to the torque of Comparative Example 1 at a load of about 300 (N).

Next, the fixing device 90 according to the third embodiment will be described with reference to FIG. The fixing device 90 shown in FIG. 9 can be used in place of the fixing device 50 in the image forming device 1 of FIG. In the description of the fixing device 90 of the third embodiment, the same description as in the first and second embodiments described above will be omitted.

The fixing device 90 includes a fixing belt 51, a pressure roller 52, a contact member 54, and a heating source (heater) 55. Further, the fixing device 90 has a separating member 56 that separates the medium P adhering to the outer peripheral surface 51a of the fixing belt 51 from the fixing belt 51. The separating member 56 is arranged downstream of the fixing nip portion 53 in the transport path R3 of the medium P.

The contact member 54 is arranged inside the fixing belt 51 and receives a pressing load from the pressurizing roller 52. The contact member 54 extends in the axial direction of the tubular fixing belt 51 and penetrates in the axial direction, the support 64 fixed to the structure 63, and the support 64. The fixed sliding member 65 is provided. The fixed sliding member 65 has a plurality of convex shapes 67.

Further, the fixing device 90 includes a reflector 92 that covers the outer surface of the contact member 54. The reflector 92 extends in the axial direction of the fixing belt 51, and has a U-shaped cross section orthogonal to the longitudinal direction. The reflector 92 includes a pair of side walls 92a facing each other in the transport direction of the medium P, and a connecting portion 92b that connects the pair of side walls 92a to each other. In the cross section shown in FIG. 9, the ends of the pair of side walls 92a (specifically, the ends on the heating source side) are connected by a connecting portion 92b.

The pair of side walls 92a are attached to the pair of side walls 65a so as to cover the pair of side walls 65a of the fixed sliding member 65. The reflector 92 reflects the radiant heat from the heating source 55 toward the inner peripheral surface 51b of the fixing belt 51. Further, the radiant heat from the inner peripheral surface 51b of the fixing belt 51 is reflected toward the inner peripheral surface 51b of the fixing belt 51.

Further, the fixing device 90 includes a lubricant supply unit 93 arranged on the upstream side of the main body portion 65b, which is the contact portion, and the main body portion in the moving direction Y of the fixing belt 51 at the contact portion of the fixed sliding member 65. A film thickness regulating unit 94 arranged on the downstream side of 65b is provided.

The lubricant supply unit 93 is arranged, for example, at the upstream end of the main body 65b of the fixed sliding member 65 in the moving direction Y of the fixing belt 51, and is attached to the fixed sliding member 65. The lubricant supply unit 93 has a length corresponding to the width of the fixing belt 51 in the axial direction of the fixing belt 51. The inside of the lubricant supply unit 93 is filled with a lubricant, and the lubricant that has exuded to the outer surface of the lubricant supply unit 93 is applied to the inner peripheral surface 51b of the fixing belt 51. Then, the lubricant adhering to the inner peripheral surface 51b moves with the movement of the fixing belt 51 and is supplied between the main body portion 63b and the inner peripheral surface 51b.

The film thickness regulating portion 94 is arranged, for example, at the downstream end of the main body portion 65b of the fixed sliding member 65 in the moving direction Y of the fixing belt 51, and is attached to the support 64. The film thickness regulating unit 94 has a length corresponding to the width of the fixing belt 51 in the axial direction of the fixing belt 51.

Further, the film thickness regulating unit 94 regulates the shape when the fixing belt 51 is rotationally moving in contact with the inner peripheral surface 51b of the fixing belt 51. The film thickness regulating portion 94 projects outward in the radial direction of the fixing belt 51 and is pressed against the inner peripheral surface 51b. Further, the film thickness regulating unit 94 regulates the film thickness of the lubricant that has moved downstream from the main body portion 65b. That is, the lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 is suppressed from moving to the downstream side by the film thickness regulating portion 94.

The film thickness regulating portion 94 is made of a non-woven fabric. The non-woven fabric is composed of, for example, heat-resistant fibers. As the heat resistance performance of the non-woven fabric, for example, it is preferable to have a heat resistance performance of 300 ° C. or higher. Further, the non-woven fabric has heat resistance and flame retardancy, and is preferably V0 or higher in the flammability UL94 standard, for example. The thickness of the non-woven fabric is, for example, 0.8 mm or more and 4.5 mm or less. The basis weight of the non-woven fabric is, for example, 200 g / m ² or more. Further, as the non-woven fabric, aramid fiber which is a heat resistant fiber can be used.

The film thickness regulating unit 94 may have, for example, a structure in which a non-woven fabric is wound around a rod-shaped member. Further, the film thickness regulating unit 94 may have a configuration in which a plurality of non-woven fabrics are laminated. Further, the film thickness regulating portion 94 may be formed of other members such as resin.

In this fixing device 90, the lubricant is supplied from the upstream of the fixed sliding member 65, and the lubricant exists between the main body portion 65b of the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51. Become. As a result, the frictional resistance between the main body portion 65b of the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51 can be reduced, and an increase in the torque of the fixing belt 51 can be suppressed. In the fixing device 90, the torque at the start of driving and during driving can be reduced.

In this fixing device 90, since a lubricant is present between the main body portion 65b of the fixed sliding member 65 and the inner peripheral surface 51b of the fixing belt 51, the fixed sliding member 65 is compared with the case where there is no lubricant. And the friction between the fixing belt 51 and the fixing belt 51 suppresses the generation of friction powder. By reducing the amount of friction powder generated in this way, contamination by friction powder is prevented. For example, the surface layer formed on the inner peripheral surface 51b of the fixing belt 51 may be peeled off to generate abrasion powder, but the fixing device 90 suppresses the generation of friction powder. Therefore, the amount of friction powder that moves downstream together with the excess lubricant is limited, and contamination inside the fixing belt 51 is suppressed on the heating source 55 side.

Further, in the fixing device 90, the film thickness of the lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 is regulated by the film thickness regulating unit 94. A lubricant having a thickness of a predetermined thickness or more hits the film thickness regulating portion 94, and its movement to the downstream side is restricted. Since the film thickness regulating portion 94 has a non-woven fabric, the excess lubricant adhering to the inner peripheral surface 51b of the fixing belt 51 is wiped off by the non-woven fabric, and the amount of adhering is reduced. Further, a small amount of abrasion powder generated by friction between the fixed sliding member 65 and the fixing belt 51 is also wiped off together with the lubricant by the non-woven fabric of the film thickness regulating portion 94, and the movement downstream from the film thickness regulating portion 94 is restricted. Will be done.

Therefore, contamination by the lubricant and abrasion powder is suppressed. Inside the fixing belt 51, the lubricant and abrasion powder adhering to the inner peripheral surface 51b of the fixing belt 51 are prevented from falling. As a result, the lubricant and abrasion powder adhering to the reflector 92 can be reduced, and the decrease in the reflection efficiency due to the reflector 92 can be suppressed. As a result, the radiant heat from the heating source 55 is efficiently transmitted to the fixing belt 51, so that the fixing belt 51 is efficiently heated. As a result, the toner image can be reliably fixed to the medium P.

Further, in the fixing device 90, since the film thickness regulating portion 94 comes into contact with the inner peripheral surface 51b of the fixing belt 51, the shape of the rotating fixing belt 51 is restricted. The shape of the fixing belt 51 is regulated by the film thickness regulating portion 94 so as to be extruded outward in the radial direction. As a result, the rotational runout of the fixing belt 51 is suppressed. The rotational runout is a position change that occurs when the fixing belt 51 rotates and moves, and is a change in the thickness direction of the fixing belt 51. In the fixing device 90, since the rotational runout is suppressed, the risk of contact between the separating member 56 arranged on the outer peripheral surface 51a side of the fixing belt 51 and the fixing belt 51 is reduced. The rotational shape (orbital trajectory) of the fixing belt 51 is stabilized, and the fixing belt 51 and the separating member 56 are prevented from unexpectedly hitting each other.

Further, in the fixing device 90, since the rotational shape of the fixing belt 51 near the outlet side of the fixing nip portion 53 is stable, the tip portion of the separating member 56 is arranged close to the outer peripheral surface 51a of the fixing belt 51. be able to. As a result, the medium P adhering to the outer peripheral surface 51a of the fixing belt 51 can be reliably peeled off.

Further, the film thickness regulating unit 94 has a plurality of functions of a function of restricting the movement of the lubricant and abrasion powder adhering to the fixing belt 51 to the downstream and a function of stabilizing the rotational shape of the fixing belt 51 as one component. It is realized by. As a result, it is not necessary to provide separate parts, the number of parts can be reduced, and the configuration of the device can be simplified.

FIG. 10 is an enlarged cross-sectional view showing the film thickness regulating portion according to the modified example. As shown in FIG. 10, the film thickness regulating portion 94 may be configured to include a protruding portion 94a protruding toward the fixing belt 51 side. The protruding portion 94a is a portion including a surface of the fixing belt 51 facing the inner peripheral surface 51b, and protrudes outward in the radial direction of the fixing belt 51. The protruding portion 94a projects toward the pressure roller 52 side from the main body portion 65b of the fixed sliding member 65. Further, the protruding portion 94a may protrude toward the pressure roller 52 side from the nip surface N. As a result, the position where the protrusion 94a and the fixing belt 51 come into contact with each other can be arranged outside the nip surface N in the radial direction. When the protruding portion 94a protrudes outward from the nip surface N in this way, the film thickness regulating portion 94 can be stably applied to the fixing belt 51, and the rotational runout of the fixing belt 51 can be reliably performed. It can be suppressed. In addition, the lubricant and abrasion powder adhering to the inner peripheral surface 51b of the fixing belt 51 can be reliably reduced.

Next, the fixing device 100 according to the fourth embodiment will be described with reference to FIG. The fixing device 100 shown in FIG. 11 is different from the fixing device 90 of the third embodiment in that the structure of the film thickness regulating section 102 is different and that the lubricant recovered by the film thickness regulating section 102 is accommodated. The point is that the lubricant accommodating portion 103 is provided. In the description of the fixing device 100 of the fourth embodiment, the same description as the fixing device of the first to third embodiments is omitted.

The fixing device 100 includes a film thickness regulating member 101 having a film thickness regulating unit 102. The film thickness regulating member 101 extends in the axial direction of the fixing belt 51. The film thickness regulating member 101 has a length corresponding to the width of the fixing belt 51 in the axial direction of the fixing belt 51. The film thickness regulating member 101 has a support portion 101a in addition to the film thickness regulating portion 102. The support portion 101a is fixed to the contact member 54.

The support portion 101a has, for example, a prismatic shape and extends in the axial direction of the fixing belt 51. The support portion 101a is fixed to, for example, a side wall 64a on the downstream side of the support 64 (downstream side in the moving direction Y of the fixing belt 51). The support portion 101a may be fixed to the structure 63 of the contact member 54.

The film thickness regulating portion 102 is continuously formed on the support portion 101a (the film thickness regulating portion 102 is integrally formed with the support portion 101a). The film thickness regulating portion 102 has a guide surface 102a, an edge portion 102b, and an inclined surface 102c. The film thickness regulating portion 102 is formed so as to project outward from the support portion 101a in the radial direction of the fixing belt 51. The film thickness regulating portion 102 has a guide surface 102a formed so as to abut the inner peripheral surface 51b of the fixing belt 51. The guide surface 102a is formed, for example, along an arc centered on the rotation center O ₅₁ of the fixing belt 51. Further, the guide surface 102a has a predetermined length in the circumferential direction of the fixing belt 51. The length of the guide surface 102a in the circumferential direction of the fixing belt 51 is, for example, about 10% of the circumferential length of the fixing belt 51.

Further, the guide surface 102a is formed of, for example, a resin. A resin having excellent heat resistance and flame retardancy can be used for the guide surface 102a. For example, polyphenylene sulfide (PPS), polyethylene terephthalate (PET), liquid crystal polymer (LCP), polyetheretherketone () PEEK) and the like can be used. Further, the guide surface 102a may be formed of a non-woven fabric.

FIG. 12 is an enlarged cross-sectional view showing the edge portion 102b of the film thickness regulating member 101. As shown in FIG. 12, the edge portion 102b, which is the end portion of the guide surface 102a on the upstream side in the moving direction Y, is the tip portion of the separating member 56 (upstream in the conveying direction of the medium P) in the circumferential direction of the fixing belt 51. It is arranged between the end portion on the side) and the main body portion 65b of the fixed sliding member 65.

In the edge portion 102b, the surface of the fixing belt 51 on the rotation center O ₅₁ side constitutes an inclined surface 102c that is inclined with respect to the tangent line L51b in contact with the inner peripheral surface 51b of the fixing belt 51. The inclination angle θ _102c of the straight line L102c along the inclined surface 102c with respect to the tangent line L51b is, for example, about 15 (deg) or more and 45 (deg) or less.

The fixing device 100 has a lubricant accommodating unit 103 for accommodating the lubricant recovered by the film thickness regulating unit 102. The lubricant accommodating portion 103 is arranged on the downstream side of the fixed sliding member 65 and on the upstream side of the edge portion 102b in the moving direction Y of the fixing belt 51. The lubricant accommodating portion 103 has an opening on the inner peripheral surface 51b side of the fixing belt 51.

The lubricant accommodating portion 103 accommodates excess lubricant in the space formed between the side wall 65a (see FIG. 1) of the fixed sliding member 65 of the contact member 54 and the film thickness regulating portion 102. The lubricant that has adhered to and moved to the fixing belt 51 hits the edge portion 102b of the film thickness regulating portion 102 and is peeled off from the fixing belt 51. The peeled lubricant moves along the inclined surface 102c of the edge portion 102b and is accommodated in the lubricant accommodating portion 103.

In such a fixing device 100 of the fourth embodiment, as in the fixing device 90 of the third embodiment, contamination by the lubricant and abrasion powder can be suppressed.

In the fixing device 100 of the fourth embodiment, the film thickness regulating member 101 and the support 64 have separate configurations, but the film thickness regulating member 101 and the support 64 are formed as an integral member. You may. As a result, the number of parts in the fixing device can be reduced, and the device can be simplified.

The present invention is not limited to the above-described embodiment, and various modifications as described below are possible without departing from the gist of the present invention.

In the above fixing device, the fixing belt 51 may have a resin base material 57, and the lubricant supply unit 93 may supply a black lubricant. As a result, the black lubricant can be applied to the inner peripheral surface 51b of the fixing belt 51. Therefore, when a resin that cannot be surface-treated in black is used as the base material of the fixing belt 51, a black lubricant is applied to the inner peripheral surface 51b of the fixing belt 51 to increase the absorption rate of radiant heat in the fixing belt 51. Can be improved. As a result, the heating efficiency can be improved and the fixing in the fixing device can be stabilized. The black lubricant is a fluorine-based lubricant to which, for example, carbon black or a black dye is added. The lubricant may be blackened by other methods.

Further, in the above embodiment, the main body portion 65b, which is the contact portion of the fixed sliding member 65, has a convex shape. However, in the fixing devices 90 and 100 according to the third and fourth embodiments, the main body portion is formed. A configuration in which a convex shape is not formed on the portion 65b may be used.

Further, the convex shape is not limited to a rectangular shape, a rhombus shape, a circular shape, and a strip shape, and may be another shape such as a trapezoidal shape or an elliptical shape.

Further, the arrangement interval of the plurality of convex shapes is not limited to 1.1 mm or more, and may be less than 1.1 mm. Further, the arrangement interval of the convex shape may be constant, and may be different depending on, for example, the position in the width direction X. Further, the contact length with the convex fixing belt is not limited to 0.55 mm or more, and may be less than 0.55 mm.

1 ... image forming apparatus, 50, 90, 100 ... fixing device, 51 ... fixing belt, 51a ... outer peripheral surface of fixing belt, 51b ... inner peripheral surface of fixing belt, 52 ... pressure roller, 53 ... fixing nip portion, 54 ... Contact member, 56 ... Separation member, 65 ... Fixed sliding member, 65b ... Main body (contact part) of fixed sliding member, 66 ... Reference surface, 67 to 69 ... Convex shape, 81 ... Fixed sliding member , 81b ... Main body (contact portion), 82,85-87 ... Belt-shaped convex shape, 83 ... Belt-shaped convex shape (lubricant holding convex portion), 94,102 ... Film thickness regulating portion, 101 ... Film thickness Regulatory member, 102a ... guide surface, 102b ... edge portion, 103 ... lubricant accommodating portion, P ... medium, X ... width direction, Y ... moving direction of fixing belt.

Claims (15)

In a fixing device in which a medium on which a toner image is formed is heated and pressure-welded by a pair of rotating bodies to fix the toner image on the medium.
A tubular fixing belt that is one of the pair of rotating bodies and
A pressure roller which is the other of the pair of rotating bodies and presses the medium against the outer peripheral surface of the fixing belt.
A contact member which is arranged inside the fixing belt and has a contact portion that contacts the inner peripheral surface of the fixing belt.
A plurality of convex shapes protruding from the reference surface toward the pressure roller side are formed in the contact portion.
The plurality of convex shapes are arranged in a plurality of rows extending in a width direction orthogonal to the moving direction of the fixing belt, and when viewed from the moving direction of the fixing belt, the fixing belt A fixing device arranged without a gap in the width direction of the above. The length of contact between one of the plurality of convex shapes and the inner peripheral surface of the fixing belt is 0.55 mm or more in the width direction of the fixing belt.
The fixing device according to claim 1, wherein the pitch between adjacent convex shapes among the plurality of convex shapes in the width direction of the fixing belt is 1.1 mm or more. The plurality of convex shapes are arranged in each of the rows at equal intervals in the width direction of the fixing belt.
A claim that the length of each convex shape of the plurality of convex shapes in the width direction of the fixing belt is larger than the gap between adjacent convex shapes among the plurality of convex shapes in the width direction of the fixing belt. The fixing device according to 1 or 2. In a fixing device in which a medium on which a toner image is formed is heated and pressure-welded by a pair of rotating bodies to fix the toner image on the medium.
A tubular fixing belt that is one of the pair of rotating bodies and
A pressure roller which is the other of the pair of rotating bodies and presses the medium against the outer peripheral surface of the fixing belt.
A contact member which is arranged inside the fixing belt and has a contact portion that contacts the inner peripheral surface of the fixing belt.
A plurality of convex shapes protruding from the reference surface toward the pressure roller side are formed in the contact portion.
The convex shape forms a band shape and extends in the width direction orthogonal to the moving direction of the fixing belt.
The convex shape has an inclined portion arranged outside in the width direction, and has an inclined portion.
The inclined portion toward the outer side in the width direction, the fixing belt inclined to have a fixing device so as to be positioned downstream from the upstream side the moving direction. Wherein one said inner peripheral surface is in contact length of the fixing belt of the plurality of convex shape, in the moving direction of the fixing belt, a fixing device according to claim 4 is at least 0.55 mm. The contact portion includes a lubricant holding convex portion for holding the lubricant between the reference surface and the inner peripheral surface of the fixing belt.
The lubricant holding protrusion extends in the moving direction of the fixing belt.
The fixing device according to claim 4 or 5 , wherein the lubricant holding convex portions are arranged on both sides of the fixing belt in the width direction, respectively. The protrusion for holding the lubricant has a band shape.
The lubricant holding convex portion is outside the image forming region, which is a region where the toner image is formed on the medium, in the width direction of the fixing belt, and is loaded by the pressurizing roller. The fixing device according to claim 6 , which is formed in a nip load region which is a region. The contact portion has a base material and a surface layer formed on the base material.
The base material comprises aluminum, stainless steel, liquid crystal polymer, a polyphenylene sulfide or we selected one material,
The fixing device according to any one of claims 1 to 7 , wherein the surface layer contains at least one selected from polytetrafluoroethylene, perfluoroalkoxy alkane resin and modified products thereof. The contact portion is made of a plate material containing at least aluminum.
The thickness of the contact portion is 0.2 mm or more and 0.5 mm or less.
The fixing device according to any one of claims 1 to 8 , wherein the plurality of convex shapes of the contact portion are formed by press working, etching processing, or laser processing. The contact portion is made of a plate material containing at least stainless steel.
The thickness of the contact portion is 0.1 mm or more and 0.3 mm or less.
The fixing device according to any one of claims 1 to 8 , wherein the plurality of convex shapes of the contact portion are formed by press working, etching processing, or laser processing. The contact portion is made of a material containing a liquid crystal polymer or polyphenylene sulfide.
The fixing device according to any one of claims 1 to 8 , wherein the plurality of convex shapes of the contact portion are formed by injection molding, etching processing, or laser processing. The fixing device is
A lubricant supply unit that is arranged on the upstream side of the fixing belt in the moving direction with respect to the contact member and supplies a lubricant to the contact portion of the contact member.
Wherein said fixing belt is arranged on the downstream side in the moving direction, the inner peripheral surface of the fixing belt together with the fixing belt in contact with the inner peripheral surface of the fixing belt to regulate the shape when rotating movement The fixing device according to any one of claims 1 to 11 , further comprising a film thickness regulating unit that regulates the film thickness of the lubricant that has adhered to and moved downstream from the contact member. The film thickness regulating portion has a protruding portion that projects outward in the radial direction of the fixing belt.
The protruding portion protrudes outward from the nip surface formed along the surfaces where the outer peripheral surfaces of the pair of rotating bodies come into contact with each other in the radial direction of the fixing belt.
The fixing device further includes a separating member for separating the medium adhering to the outer peripheral surface of the fixing belt,
The separating member is provided on the outlet side of the nip portion where the medium is sandwiched by the pair of rotating bodies.
The protrusion, the in the moving direction of the fixing belt, the fixing device according to claim 12, which is disposed between the contact member and the separating member. The film thickness regulating portion has a guide surface that abuts on the inner peripheral surface of the fixing belt.
The guide surface is curved along the circumferential direction of the fixing belt.
The film thickness control unit
An edge portion of the guide surface formed at the upstream end of the fixing belt in the moving direction and scraping off the lubricant adhering to the inner peripheral surface of the fixing belt.
A lubricant accommodating portion that is located on the downstream side of the abutting member and upstream of the edge portion in the moving direction of the fixing belt and accommodates the lubricant scraped off by the edge portion.
Have,
The edge portion has an inclined surface inclined against the tangent in contact with the inner peripheral surface of the fixing belt,
The inclined surface is a surface of the rotation center side of the fixing belt of the edge portion, fixing device according to claim 12 which is inclined with respect to tangent to the inner circumferential surface of the fixing belt. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 14 .

Images