Fixing device, and image forming apparatus

Abstract

To provide a fixing device that reduces scratches on an inner peripheral surface of a fixing member (second rotating body).SOLUTION: A fixing device comprises: a first rotating body; a second rotating body that is disposed in contact with the first rotating body; a pressing member that is disposed on an inner peripheral surface of the second rotating body, and presses the second rotating body toward the first rotating body from the inner peripheral surface of the second rotating body; a slide member that is interposed between the inner peripheral surface of the second rotating body and the pressing member; and lubricant that is interposed between the inner peripheral surface of the second rotating body and the slide member. The slide member has a slide surface having irregularities, and having a surface roughness Ra1 of 0.20 μm or more and a load length rate Rmr of 35% or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a fixing device and an image forming apparatus.

Background Art

[0002] For example, Patent Document 1 discloses "a sliding member for an electrophotographic apparatus having irregularities on its surface and having a lubricant interposed therebetween and the sliding member and the surface with which it comes into contact, wherein at least the ten-point mean roughness Rz in the sliding direction of the surface is larger than the ten-point mean roughness surface roughness Rz in the direction perpendicular to the sliding direction."

[0003] Further, Patent Document 2 discloses "a belt device including a rotatable endless belt, a sliding member that relatively slides on the inner peripheral surface of the belt, a pressing member that contacts the sliding member via the belt and forms a nip portion therebetween, and a lubricant interposed between the inner peripheral surface of the belt and the sliding member, wherein among the sliding surfaces on which the belt and the sliding member slide, the elastic work rate of the sliding surface of the belt is 55% or more, and the surface roughness of the sliding surface of the sliding member is larger than the surface roughness of the sliding surface of the belt."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventionally, a fixing device (hereinafter also referred to as a specific fixing device) has been known, which includes a first rotating body, a second rotating body disposed in contact with the first rotating body, a pressing member disposed on the inner peripheral surface of the second rotating body and pressing the second rotating body against the first rotating body from the inner peripheral surface of the second rotating body, a sliding member interposed between the inner peripheral surface of the second rotating body and the pressing member, and a lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member.

[0006] An object of the present invention is to provide a fixing device in which damage to the inner peripheral surface of a fixing member (that is, the second rotating body) is reduced as compared with a case where the surface roughness Ra1 of the sliding member is less than 0.20 μm or the load length ratio Rmr of the sliding surface of the sliding member is less than 35% in a specific fixing device.

Means for Solving the Problem

[0007] Specific means for solving the above problems include the following aspects. <1> A first rotating body, a second rotating body disposed in contact with the first rotating body, a pressing member disposed on the inner peripheral surface of the second rotating body and pressing the second rotating body against the first rotating body from the inner peripheral surface of the second rotating body, a sliding member interposed between the inner peripheral surface of the second rotating body and the pressing member, a lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member, and the sliding member has a sliding surface having irregularities, a surface roughness Ra1 of 0.20 μm or more, and a load length ratio Rmr of 35% or more, a fixing device. <2> The fixing device according to <1> or <2>, wherein the surface roughness Ra1 is 0.20 μm or more and 5.00 μm or less. <3> The fixing device according to <1>, wherein the load length ratio Rmr is 36% or more and 75% or less. <4> The fixing device according to any one of <1> to <3>, wherein the sliding member has a planar heating element. <5> The fixing device according to <4>, wherein the sliding member has a glass layer on the sliding surface. <6> The surface roughness Ra1 of the sliding surface of the sliding member is less than the surface roughness Ra2 of the inner peripheral surface of the second rotating body, and the fixing device according to any one of <1> to <5>. <7> The difference (Ra1 - Ra2) between the surface roughness Ra1 of the sliding surface of the sliding member and the surface roughness Ra2 of the inner peripheral surface of the second rotating body is 0.05 μm or more and 2.00 μm or less, and the fixing device according to <6>. <8> The hardness A of the sliding surface of the sliding member is higher than the hardness B of the inner peripheral surface of the second rotating body, and the fixing device according to any one of <1> to <7>. <9> The difference (A - B) between the hardness A of the sliding surface of the sliding member and the hardness B of the inner peripheral surface of the second rotating body is 10 or more and 600 or less, and the fixing device according to <8>. <10> The viscosity of the lubricant is 20 mm 2 / s or more and 1000 mm 2 / s or less, and the fixing device according to any one of <1> to <9>. <11> An image forming apparatus including a photoreceptor, a latent image forming device that forms a latent image on the surface of the photoreceptor, a developing device that develops the latent image into a toner image using a developer, a transfer device that transfers the toner image developed on a recording medium, the fixing device according to any one of <1> to <10> that fixes the toner image on the recording medium, and a controller that controls the latent image forming device, the developing device, the transfer device, and the fixing device.

Advantages of the Invention

[0008] According to the invention according to <1>, in a specific fixing device, when the surface roughness Ra1 of the sliding surface of the sliding member is less than 0.20 μm, or when the load length ratio Rmr of the sliding surface of the sliding member is less than 35%, a fixing device is provided in which scratches on the inner peripheral surface of the fixing member are reduced as compared with the case where the surface roughness Ra1 of the sliding surface of the sliding member is 0.20 μm or more and the load length ratio Rmr of the sliding surface of the sliding member is 35% or more. According to the invention according to <2>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the surface roughness Ra1 is less than 0.20 μm or more than 5.00 μm. According to the invention according to <3>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the load length ratio Rmr is less than 36% or more than 75%. According to the invention according to <4>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the sliding member is a pressing member having no heater. According to the invention according to <5>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the sliding member does not have a glass layer on the outermost surface on the pressing member side. According to the invention according to <6>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the surface roughness Ra1 of the sliding surface of the sliding member is a value larger than the surface roughness Ra2 of the inner peripheral surface of the second rotating body. According to the invention according to <7>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the difference (Ra1 - Ra2) between the surface roughness Ra1 of the sliding surface of the sliding member and the surface roughness Ra2 of the inner peripheral surface of the second rotating body is less than 0.05 μm or more than 2.00 μm. According to the invention according to <8>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the hardness A of the sliding surface of the sliding member is a value lower than the hardness B of the inner peripheral surface of the second rotating body. According to the invention according to <9>, in a specific fixing device, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the difference (A - B) between the hardness A of the sliding surface of the sliding member and the hardness B of the inner peripheral surface of the second rotating body is less than 10 or more than 600. According to the invention according to <10>, in a specific fixing device, the viscosity of the lubricant is 20 mm 2 / s or less or 1000 mm 2 / s or more, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced. According to the invention according to <11>, an image forming apparatus including a fixing device in which the sliding surface roughness Ra1 of the sliding member is less than 0.20 μm or the load length ratio Rmr of the sliding surface of the sliding member is less than 35% provides an image forming apparatus including a fixing device in which scratches on the inner peripheral surface of the fixing member are reduced, as compared with an image forming apparatus including a fixing device in which the sliding surface roughness Ra1 of the sliding member is less than 0.20 μm or the load length ratio Rmr of the sliding surface of the sliding member is less than 35%.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment which is an example of the present invention will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the invention. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0011] Each component may contain a plurality of corresponding substances. When referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0012] When describing embodiments with reference to the drawings, members having substantially the same function may be given the same reference numerals throughout the drawings, and redundant descriptions may be omitted.

[0013] <Fixing device / Image forming apparatus> The fixing device according to the present embodiment includes a first rotating body, a second rotating body disposed in contact with the first rotating body, a pressing member disposed on the inner peripheral surface of the second rotating body and pressing the second rotating body from the inner peripheral surface of the second rotating body toward the first rotating body, a sliding member interposed between the inner peripheral surface of the second rotating body and the pressing member, and a lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member. The sliding member has an uneven sliding surface, a surface roughness Ra1 of 0.20 μm or more, and a load length ratio Rmr of 35% or more.

[0014] The image forming apparatus according to the present embodiment an image carrier, a latent image forming device that forms a latent image on the surface of the image carrier, a developing device that develops the latent image into a toner image using a developer, a transfer device that transfers the toner image developed on a recording medium, a fixing device that fixes the toner image on the recording medium, and includes. And, in the image forming apparatus according to the present embodiment, the fixing device according to the above-described present embodiment is applied.

[0015] The fixing device and the image forming apparatus according to the present embodiment are excellent in both low slidability and charge suppression due to the above-described configuration. The reason is presumed as follows.

[0016] Conventionally, in order to form an image on an electrophotographic image forming apparatus such as a printer, a copier, or a facsimile, after transferring a toner image onto a recording medium such as recording paper, the recording medium onto which the toner image has been transferred is heated and pressed by a fixing device to fix the toner image on the surface of the recording medium.

[0017] Conventionally, various types of devices have been proposed as this fixing device, and among them, the above-mentioned specific fixing device is known.

[0018] In a conventional specific fixing device, from the viewpoint of holding a lubricant between the inner peripheral surface of the second rotating body and the sliding surface of the sliding member, a sliding member having irregularities on the sliding surface has been proposed. However, in the conventional sliding member, due to the uneven shape of its sliding surface, the inner peripheral surface of the second rotating body (for example, a fixing belt such as a pressure belt) tends to be damaged during sliding. Therefore, in this locally damaged region, it is difficult to hold the lubricant, and since the sliding member and the second rotating body come into direct contact, the rotational torque tends to increase and the second rotating body tends to wear.

[0019] On the other hand, in the fixing device according to the present embodiment, the sliding surface of the sliding member has irregularities, the surface roughness Ra1 is 0.20 μm or more, and the load length ratio Rmr is 35% or more. Here, the load length ratio Rmr will be described with reference to the drawings. FIG. 4 is a schematic diagram regarding the method for obtaining the load length ratio Rmr. As shown in FIG. 4, first, for the sliding surface of the sliding member, a roughness curve in the axial direction is obtained, and a reference length L is extracted in the direction of the average line of the roughness curve. Then, the ratio of the sum of the cut lengths (load length ηp = b1 + b2 +... + bn) obtained when the roughness curve of this extracted portion is cut at a cutting level c (%) parallel to the peak line to the reference length L is expressed as a percentage, which is the load length ratio Rmr (= ηp / L × 100). Note that the cutting level c when obtaining the load length ratio Rmr represents the ratio of the maximum height Ry, which is the interval between the peak line and the valley line of the extracted portion, as a percentage, and shows the value when the highest peak is 0% and the lowest valley is 100%.

[0020] As described above, the load length ratio Rmr represents the degree of smoothness of the convex portions on the sliding surface of the sliding member. Then, the fact that this load length ratio Rmr is 35% or more and the surface roughness Ra1 is 0.20 μm or more means that the sliding surface of the sliding member that contacts the inner peripheral surface of the second rotating body has unevenness while the tips of the convex portions are blunted, that is, it is moderately smooth. Therefore, scratches on the inner peripheral surface of the second rotating body are reduced even during sliding. As a result, it is considered that the lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member is easily retained, and an increase in rotational torque and wear of the inner peripheral surface of the second rotating body are suppressed.

[0021] Hereinafter, an example of the image forming apparatus according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the image forming apparatus according to the present embodiment. FIG. 2 is a schematic diagram showing an example of the fixing device according to the present embodiment. FIG. 3 is a plan view showing an example of the planar heating element 64 of the fixing device according to the present embodiment.

[0022] (Configuration of the image forming apparatus) As shown in FIG. 1, the image forming apparatus 100 according to the present embodiment includes electrophotographic first to fourth process cartridges 10Y, 10M, 10C, and 10K (an example of an image forming unit) that output images of respective colors of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These process cartridges 10Y, 10M, 10C, and 10K are arranged side by side at intervals along the outer peripheral surface of the intermediate transfer belt 20. Note that these process cartridges 10Y, 10M, 10C, and 10K are detachable from the image forming apparatus main body.

[0023] Above each of the process cartridges 10Y, 10M, 10C, and 10K (in FIG. 1), an intermediate transfer belt 20 as an intermediate transfer member is provided such that its outer peripheral surface faces each of the process cartridges. The intermediate transfer belt 20 is wound around a driving roller 22 and a support roller 24 that are spaced apart from each other and in contact with the inner peripheral surface of the intermediate transfer belt 20 to apply tension thereto, and is arranged to travel endlessly in the direction from the first process cartridge 10Y to the fourth process cartridge 10K.

[0024] Note that the support roller 24 is pressed in a direction away from the driving roller 22 by an elastic member such as a spring (not shown), and tension is applied to the intermediate transfer belt 20 wound between the two. Further, an intermediate transfer member cleaning device 20a is provided on the outer peripheral surface of the intermediate transfer belt 20 so as to face the driving roller 22.

[0025] Since the first to fourth process cartridges 10Y, 10M, 10C, and 10K have substantially the same configuration, here, the first process cartridge 10Y that forms a yellow image disposed on the upstream side in the traveling direction of the intermediate transfer belt will be described as a representative. In addition, the same reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) are assigned to the same portions as the first process cartridge 10Y, and the description of the second to fourth process cartridges 10M, 10C, and 10K will be omitted.

[0026] The first process cartridge 10Y has a photoreceptor 1Y that acts as an image holding member. Around the photoreceptor 1Y, a charging roller (an example of a charging device) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, a developing device 4Y that supplies charged toner contained in the developer to the electrostatic latent image to develop the electrostatic latent image, and a photoreceptor cleaning device 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after primary transfer are sequentially arranged. These are integrally configured within a housing 11Y (a casing). Similarly, for the first process cartridges 10M to 10Y, each member is integrally configured within housings 11M to 11Y (casings).

[0027] Then, together with the first process cartridge 10Y, a primary transfer roller 5Y (an example of a primary transfer device) that transfers the developed toner image onto the intermediate transfer belt 20, and an exposure device 3 that forms an electrostatic latent image by exposing the charged surface with a laser beam 3Y based on the color-separated image signal are arranged to constitute an image forming unit. Note that the charging roller 2Y and the exposure device 3 correspond to an example of a latent image forming device.

[0028] Note that the primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 and provided at a position facing the photoreceptor 1Y. Further, bias power supplies (not shown) for applying a primary transfer bias are connected to the respective primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

[0029] (Configuration of Fixing Device) As shown in FIG. 2, the fixing device 60 includes a cylindrical pressure roller 52 (an example of a first rotating body) extending in the depth direction of the device, a pressure belt 62 (an example of a second rotating body), and a planar heating element 64 (an example of a sliding member). Further, the fixing device 60 includes a pressing member 68 that holds the planar heating element 64 and a frame member 72 that supports the pressing member 68.

[0030] The planar heating element 64 generates heat for heating. The planar heating element 64 is arranged inside the pressure belt 62 and on the opposite side of the pressure roller 52 with the pressure belt 62 interposed therebetween. This planar heating element 64 is a plate-shaped member whose plate surface faces the width direction of the device and extends from one end to the other end of the pressure belt 62 in the depth direction of the device.

[0031] As shown in FIG. 3, the planar heating element 64 has a rectangular shape extending in the depth direction of the apparatus when viewed from the plate thickness direction. The planar heating element 64 includes an electrically insulating base material 64A, an insulating layer 64B formed of a heat-resistant resin material, and a pair of electrodes 64C for voltage application. Further, the planar heating element 64 has a plurality of resistance heating portions 64D that generate heat when a voltage is applied to the electrodes 64C, and a pair of connection portions 64E that electrically connect both ends of each electrode 64C and the resistance heating portion 64D. The electrodes 64C, the resistance heating portions 64D, and the connection portions 64E are formed on the base material 64A, and the resistance heating portions 64D and the connection portions 64E are covered with the insulating layer 64B from the opposite side of the base material 64A.

[0032] Next, the operation of the fixing device 60 will be described. When fixing the toner image transferred to the sheet member P to the sheet member P, the pressure roll 52 is rotated by a rotational force transmitted from a motor (not shown) and rotates in the direction of arrow R1 as shown in FIG. 2. As a result, the pressure belt 62 in contact with the pressure roll 52 orbits in the direction of arrow R2 following the rotating pressure roll 52 while sliding on the planar heating element 64. A lubricant S is held between the inner peripheral surface 90 of the pressure belt 62 and the planar heating element 64. The lubricant S suppresses an increase in the sliding resistance generated between the pressure belt 62 and the planar heating element 64.

[0033] · Surface roughness Ra The surface roughness Ra1 of the sliding surface of the sliding member is 0.20 μm or more, preferably 0.20 μm or more and 5.00 μm or less, more preferably 0.20 μm or more and 2.00 μm or less, and even more preferably 0.20 μm or more and 1.00 μm or less. When the surface roughness Ra1 is below the upper limit value, it is more suppressed that the unevenness on the sliding surface of the sliding member damages the inner peripheral surface of the second rotating body. When the surface roughness Ra1 is above the lower limit value, it becomes easier to appropriately hold the lubricant interposed between the sliding member and the second rotating body.

[0034] The method for setting the surface roughness Ra1 of the sliding surface of the sliding member within the above range is not particularly limited. For example, a method of forming the sliding surface of the sliding member as a glass layer and polishing the surface of the glass layer with sandpaper having a predetermined particle size (for example, 0.05 μm or more and 0.15 μm or less) to form a convex shape; a method of forming the sliding surface of the sliding member as a glass layer and setting the firing temperature after forming the glass layer to 550°C or more and 1000°C or less (more preferably 700°C or more and 900°C or less); and the like can be mentioned.

[0035] The surface roughness Ra2 of the inner peripheral surface of the second rotating body is preferably 0.20 μm or more and 3.00 μm or less, more preferably 0.25 μm or more and 2.00 μm or less, and even more preferably 0.30 μm or more and 1.00 μm or less. When the surface roughness Ra2 of the inner peripheral surface of the second rotating body is equal to or less than the upper limit value, it is more suppressed that the lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member is discharged from the uneven portions on the inner peripheral surface of the second rotating body. When the surface roughness Ra2 of the inner peripheral surface of the second rotating body is equal to or greater than the lower limit value, the lubricant interposed between the sliding member and the second rotating body is more likely to be appropriately retained.

[0036] The method for setting the surface roughness Ra2 of the inner peripheral surface of the second rotating body within the above range is not particularly limited. For example, a method of performing uneven processing on the inner peripheral surface (for example, a pressure belt) of the second rotating body by shot blasting or the like (more preferably, adjusting the shot blasting time per unit area, bead diameter, etc. in shot blasting) and the like can be mentioned.

[0037] The surface roughness Ra1 and the surface roughness Ra2 are obtained as follows. A part of the surface layer of the sliding surface of the sliding member or the inner peripheral surface of the second rotating body is cut out with a cutter or the like to obtain a measurement sample. This measurement sample is measured using a stylus-type surface roughness measuring instrument (Surfcom 1400A: manufactured by Tokyo Seimitsu Co., Ltd., etc.). The measurement conditions shall comply with JIS B0601-1994, with an evaluation length Ln = 2.5 mm, a reference length L = 0.8 mm, and a cut-off value = 0.008 mm.

[0038] The surface roughness Ra1 of the sliding surface of the sliding member is preferably smaller than the surface roughness Ra2 of the inner peripheral surface of the second rotating body. When the surface roughness Ra1 is smaller than the surface roughness Ra2, the sliding surface of the sliding member has less unevenness than the inner peripheral surface of the second rotating body. Therefore, when the sliding member comes into contact with and slides on the second rotating body, the occurrence of scratches on the inner peripheral surface of the second rotating body is more suppressed.

[0039] The difference (Ra1 - Ra2) between the surface roughness Ra1 of the sliding surface of the sliding member and the surface roughness Ra2 of the inner peripheral surface of the second rotating body is preferably 0.05 μm or more and 2.00 μm or less, more preferably 0.07 μm or more and 1.00 μm or less, and even more preferably 0.08 μm or more and 0.60 μm or less. When the above difference is equal to or less than the upper limit value, the convex portions of the unevenness on the sliding surface of the sliding member are more suppressed from damaging the inner peripheral surface of the pressure belt 62. When the load length ratio Rmr is equal to or less than the lower limit value, the unevenness of the sliding surface of the sliding member is appropriately maintained, and the lubricant interposed between the pressure belt 62 and the sliding member is more easily retained. As a result, the inner peripheral surface of the pressure belt 62 is more suppressed from being damaged.

[0040] · Load length ratio Rmr The load length ratio Rmr of the sliding surface of the sliding member is 35% or more, preferably 36% or more and 75% or less, more preferably 37% or more and 70% or less, and even more preferably 38% or more and 65% or less. These values are the values when the cutting level is 10%. When the load length ratio Rmr is equal to or more than the lower limit value, the convex portions of the unevenness on the sliding surface of the sliding member are more suppressed from damaging the inner peripheral surface of the pressure belt 62. When the load length ratio Rmr is equal to or less than the upper limit value, the unevenness of the sliding surface of the sliding member is appropriately maintained, and the lubricant interposed between the pressure belt 62 and the sliding member is more easily retained. As a result, the inner peripheral surface of the pressure belt 62 is more suppressed from being damaged.

[0041] The load length ratio Rmr (c%) of the sliding surface of the sliding member (where c represents the cutting level (%)) is a value measured as follows in accordance with JIS B 0601-1994.

[0042] The method of setting the load length ratio Rmr of the sliding surface of the sliding member within the above range is not particularly limited. For example, a method of making the sliding surface of the sliding member a glass layer and polishing the surface of the glass layer with sandpaper or the like having a predetermined particle size (for example, 0.05 μm or more and 0.15 μm or less) to form a convex shape; a method of making the sliding surface of the sliding member a glass layer and setting the firing temperature after forming the glass layer to 550°C or more and 1000°C or less (more preferably 700°C or more and 900°C or less); and the like can be mentioned.

[0043] · Hardness The hardness A of the sliding surface of the sliding member (sliding member) is preferably higher than the hardness B of the inner peripheral surface of the second rotating body. Thereby, it is further suppressed that the sliding surface of the sliding member becomes too hard and scratches are generated on the inner peripheral surface of the pressure belt 62.

[0044] The difference (A - B) between the hardness A of the sliding surface of the sliding member (sliding member) and the hardness B of the inner peripheral surface of the second rotating body is preferably 10 or more and 600 or less, more preferably 10 or more and 500 or less, and even more preferably 50 or more and 100 or less. Thereby, it is further suppressed that the sliding surface of the sliding member becomes too hard and scratches are generated on the inner peripheral surface of the pressure belt 62.

[0045] The hardness A of the sliding surface of the sliding member (sliding member) is preferably 100 or more and 600 or less, and more preferably 500 or more and 600 or less. When the hardness A of the sliding surface of the sliding member is equal to or less than the upper limit value, it is further suppressed that the material of the sliding member becomes too hard and damages the inner peripheral surface of the pressure belt 62. On the other hand, when it is equal to or more than the lower limit value, the lubricant interposed between the sliding member and the inner peripheral surface of the pressure belt 62 is more easily retained.

[0046] The method of setting the hardness A of the sliding surface of the sliding member (sliding member) within the above range is not particularly limited. For example, a method of making the sliding surface of the sliding member a glass layer can be mentioned.

[0047] It is preferable that the hardness B of the inner peripheral surface of the second rotating body is 70 or more and 500 or less, and more preferably 100 or more and 400 or less. When the hardness B of the inner peripheral surface of the second rotating body is within the above range, excessive friction occurs during the sliding between the sliding member and the second rotating body, and scratches on the inner peripheral surface of the second rotating body are further reduced.

[0048] The method for making the hardness B of the inner peripheral surface of the second rotating body within the above range is not particularly limited. For example, there are methods such as making the inner peripheral surface of the second rotating body a resin layer or a plating layer, or adding ceramic or carbon-based fillers.

[0049] The hardness of the sliding surface of the sliding member and the inner peripheral surface of the second rotating body is the Vickers hardness and is measured by the following method. Using a microhardness tester (MVK-HVL, manufactured by Akashi Seisakusho), a indenter is pressed into the surface of the measurement object, and the Vickers hardness Hv is measured under the conditions of a pressing load of 10 gf and a pressing time of 20 s. The measurement is performed at a location 20 μm deep from the surface after cutting the surface of the conductive support. Then, this operation is carried out at five locations, and the average value is taken as the Vickers hardness Hv.

[0050] -Pressing roll 52 (an example of the first rotating body)- The pressing roll 52 includes, for example, a metal shaft portion 54 having a heating source such as a halogen lamp inside and extending in the depth direction of the apparatus, a cylindrical elastic body layer 56 through which the shaft portion 54 passes, and a release layer 58 covering the elastic body layer 56.

[0051] The shaft portion 54 is composed of, for example, a metal cylindrical body such as aluminum or stainless steel. The elastic body layer 30b is composed of, for example, HTV silicone rubber or fluororubber (rubber hardness of about 45 degrees according to JIS-A, and the rubber hardness was measured in accordance with JIS K6301 by adding a load of 1,000 gf using a spring-type A hardness tester manufactured by Teclock) with a thickness of about 2 mm or more and 5 mm or less. The release layer 58 is composed of, for example, fluororubber, silicone rubber, fluororesin, silicone resin, etc. with a thickness of 20 μm or more and 50 μm or less. Of course, it is not limited to these, and it may be composed of conventionally known materials.

[0052] The pressure roll 52 has its speed adjusted by a drive source (not shown) for the fixing roll and is rotationally driven, for example, at a peripheral speed of 260 mm / sec. The outer diameter of the pressure roll 52 is generally about 25 mm or more and 80 mm or less, for example.

[0053] The surface temperature of the pressure roll 52 is detected by a temperature sensor (not shown) in contact with the surface and is controlled by a control circuit (not shown) so that the surface temperature becomes, for example, 175°C.

[0054] - Pressure belt 62 (an example of the second rotating body)- The pressure belt 62 is composed of at least a resin. This resin is a heat-resistant resin. Note that "heat resistance" means the property of not melting or decomposing even when the temperature of the fixing device rises to the temperature for fixing (for example, the fixing temperature). The same applies hereinafter.

[0055] The pressure belt 62 may be a single layer of a resin base layer, or a laminate having a resin base layer, an elastic layer provided on the resin base layer, and a release layer provided on the elastic layer, or a laminate having a resin base layer and a release layer provided on the resin base layer. The resin base layer may contain a conductive material in addition to the resin as required.

[0056] Examples of the resin contained in the resin base layer include polyimide resin, polyamideimide resin, polyetheretherketone resin, polyphenylene sulfide resin, polyethersulfone resin, polysulfone resin, polyphenylsulfone resin, etc. The resin may be a single kind alone or a combination of two or more kinds. Among these, it is more preferable to contain a polyimide resin as the resin.

[0057] Examples of the polyimide resin include imidized products of polyamic acids (precursors of polyimide resins), which are polymers of tetracarboxylic dianhydrides and diamine compounds. Examples of the polyimide resin include resins having a structural unit represented by the following general formula (I).

[0058] [Chemical formula]

[0059] In the general formula (I), R 1 represents a tetravalent organic group, and R 2 represents a divalent organic group. Examples of the tetravalent organic group represented by R 1 include aromatic groups, aliphatic groups, cycloaliphatic groups, groups combining aromatic groups and aliphatic groups, or groups substituted therewith. Specific examples of the tetravalent organic group include residues of tetracarboxylic dianhydrides described later. Examples of the divalent organic group represented by R 2 include aromatic groups, aliphatic groups, cycloaliphatic groups, groups combining aromatic groups and aliphatic groups, or groups substituted therewith. Specific examples of the divalent organic group include residues of diamine compounds described later.

[0060] Specific examples of the tetracarboxylic dianhydride used as a raw material for the polyimide resin include pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,3,3',4-biphenyl tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)sulfonic acid dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, ethylene tetracarboxylic dianhydride, and the like.

[0061] Specific examples of the diamine compound used as a raw material for the polyimide resin include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, 3,3'-diaminodiphenyl methane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl 4,4'-biphenyldiamine, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl propane, 2,4-bis(β-aminotert-butyl)toluene, bis(p-β-amino-tert-butylphenyl) ether, bis(p-β-methyl-δ-aminophenyl) benzene, bis-p-(1,1-dimethyl-5-aminopentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di(p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 1,2-diaminooctadecane, 2,2-bis〔4-(4-aminophenoxy)phenyl〕propane, piperazine, H2N(CH2)3O(CH2)2O(CH2)NH2, H2N(CH2)3S(CH2)3NH2, H2N(CH2)3N(CH3)2(CH2)3NH2, and the like.

[0062] Examples of the polyamideimide resin include resins having an imide bond and an amide bond in the repeating unit. More specifically, examples of the polyamideimide resin include polymers of a trivalent carboxylic acid compound having an acid anhydride group (also referred to as tricarboxylic acid), and a diisocyanate compound or a diamine compound.

[0063] As the tricarboxylic acid, trimellitic anhydride and its derivatives are preferable. In addition to the tricarboxylic acid, a tetracarboxylic dianhydride, an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, etc. may be used in combination.

[0064] Examples of the diisocyanate compound include 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, and the like. Examples of the diamine compound include compounds having the same structure as the above isocyanate and having an amino group instead of an isocyanato group. The resin base material layer may contain other components in addition to the resin. Examples of the other components include a conductive material, a filler for improving mechanical strength, an antioxidant for preventing thermal degradation, a surfactant, a heat aging inhibitor, and the like.

[0065] Here, an example in which the first rotating body is a pressure roll and the second rotating body is a pressure belt has been given, but an embodiment in which the first rotating body is a pressure roll and the second rotating body is a heating belt is also included. When the first rotating body is a pressure roll, the configuration of the pressure roll is preferably the same as the configuration of the pressure roll 52 described above. When the second rotating body is a heating belt, the configuration of the heating belt is preferably the same as the configuration of the pressure belt 62 described above. In particular, when the second rotating body is a heating belt, it may be a single layer of a resin base material layer constituting the inner peripheral surface of the heating belt, or a laminate having a resin base material layer constituting the inner peripheral surface of the heating belt, an elastic layer provided on the resin base material layer, and a release layer provided on the elastic layer, or a laminate having a resin base material layer constituting the inner peripheral surface of the heating belt and a release layer provided on the resin base material layer, or a laminate in which a metal layer is provided on a resin base material layer constituting the inner peripheral surface of the heating belt and an elastic layer is provided thereon, and a release layer is provided on the elastic layer.

[0066] The elastic layer will be described. The elastic layer is composed of a heat-resistant elastic material. Examples of the heat-resistant elastic material include silicone rubber, fluororubber, etc. Examples of silicone rubber include RTV (Room Temperature Vulcanizing) silicone rubber, HTV (High Temperature Vulcanizing) silicone rubber, liquid silicone rubber, etc. Specifically, polydimethylsilicone rubber, methylvinylsilicone rubber, methylphenylsilicone rubber, fluorosilicone rubber, etc. can be mentioned. Examples of fluororubber include vinylidene fluoride-based rubber, ethylene tetrafluoride / propylene-based rubber, ethylene tetrafluoride / perfluoromethyl vinyl ether rubber, phosphazene-based rubber, fluoropolyether, etc.

[0067] The elastic layer may contain other components. Examples of other components include fillers, conductive materials, softeners (such as paraffin-based), processing aids (such as stearic acid), anti-aging agents (such as amine-based), vulcanizing agents (such as sulfur, metal oxides, peroxides), functional fillers (such as alumina), etc.

[0068] The release layer will be described. The release layer contains, for example, a heat-resistant release material. Examples of the heat-resistant release material include fluororubber, fluororesin, silicone resin, polyimide resin, etc. Among these, as the heat-resistant release material, a fluororesin is preferable. Specific examples of the fluororesin include, for example, polytetrafluoroethylene (PTFE); tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), tetrafluoroethylene-perfluoroethyl vinyl ether copolymer (EFA), tetrafluoroethylene-perfluoropropyl vinyl ether copolymer, and other tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers (PFA). Further, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), polyvinyl fluoride (PVF), etc. can be mentioned. Among these, particularly from the aspects of heat resistance, mechanical properties, etc., polytetrafluoroethylene (PTFE), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers (PFA) such as tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA) and tetrafluoroethylene-perfluoroethyl vinyl ether copolymer (EFA) are preferably used. The thickness of the release layer is preferably set to 5 μm to 100 μm, more preferably 10 μm to 30 μm.

[0069] - Pressing member 68 (an example of a pressing member)- As shown in FIG. 2, the pressing member 68 is disposed on the inner surface 90 of the pressure belt 62 and on the opposite side of the pressure roll 52 with the planar heating element 64 interposed therebetween. This pressing member 68 is formed of a resin material such as a highly heat-resistant LCP (liquid crystal polymer) and extends in the depth direction of the apparatus.

[0070] And, the cross-section orthogonal to the longitudinal direction of the pressing member 68 is U-shaped with the side of the planar heating element 64 being open, and the pressing member 68 is in contact with the planar heating element 64 at both ends of the pressing member 68 as viewed from the depth direction of the apparatus, holding the planar heating element 64.

[0071] - Planar heating element 64 (an example of a sliding member)- The sliding member is interposed between the inner peripheral surface of the second rotating body and the pressing member. The sliding member may be a resin sheet made of a heat-resistant resin as long as the sliding surface has irregularities and the surface roughness Ra1 and the load length ratio Rmr satisfy the above-mentioned ranges, or may be an aspect having a planar heating element such as a metal plate. When the sliding member is a resin sheet, well-known other additives may be added to the sliding member. The sliding member may be a single type or a combination of two or more types. When the planar heating element 64 described later is included in two or more types of sliding members, the sliding member that is the planar heating element 64 is provided on the sliding surface side.

[0072] Examples of the heat-resistant resin include fluororesin, polyimide resin, polyamide resin, polyamideimide resin, polyetherimide resin, polyethersulfone resin, polyetherketone resin, bismaleimide triazine resin, aramid resin, polyphenylene resin, polyphenylene sulfide resin, etc. Among them, fluororesin is preferable from the viewpoints of heat resistance and slidability.

[0073] Preferable examples of the fluororesin also include fluororesin subjected to electron beam crosslinking. Specifically, for example, polytetrafluoroethylene (PTFE) subjected to electron beam crosslinking is preferably used. Note that a fluororesin subjected to electron beam crosslinking (for example, electron beam crosslinked PTFE) may be blended with an uncrosslinked fluororesin (for example, uncrosslinked PTFE) and used.

[0074] Note that the heat-resistant resin is a resin that does not melt or decompose even when the temperature of the device rises (for example, the fixing temperature).

[0075] The sliding member may be porous (having a large number of pores). Thereby, the lubricant holding ability is improved. Examples of the porous sliding member include those obtained by foaming a heat-resistant resin to make it porous, those obtained by stretching a heat-resistant resin in a uniaxial or biaxial direction to make it porous, or sintering molding.

[0076] In addition, when a porous sliding member is employed, it is preferable to interpose a lubricant permeation prevention member (sheet member) for preventing the penetration of the lubricant S between the sliding member and the pressing pad 50 on the side of the pressing member 68.

[0077] The sliding member preferably satisfies the above-mentioned ranges of the surface roughness Ra1 and the load length ratio Rmr, and from the viewpoint of further improving the fixing property of the recording medium, an aspect having a planar heating element such as a metal plate is preferable, and it is more preferable that the planar heating element has a glass layer on the sliding surface.

[0078] The planar heating element is formed, for example, as a long plate-like body along the longitudinal direction of a heating portion such as a nip, and includes an electrically insulating base material, an insulating layer formed of a polyimide-based heat-resistant resin, a pair of electrodes for power supply, and a resistor made of, for example, stainless steel that generates heat when power is supplied from this electrode. Further, the electrode and the resistor are connected by a power supply portion, and the electrode, the power supply portion, and the resistance heating portion are buried in the insulating layer. And the electrode of the planar heating element is grounded with the resistor interposed therebetween.

[0079] The glass layer refers to silica glass; water glass (including aqueous solutions such as sodium metasilicate and sodium silicate); oxide glass (for example, borate glass mainly composed of B2O3, glass mainly composed of P2O5, GeO2, TeO2, V2O5, etc.); non-oxide glass (for example, glass mainly composed of chalcogenides such as As2S3, GeS2, As2Se3; including halide glasses such as ZrF4, BaF2, AlF3, etc.). Note that silica glass refers to a layer of silicon dioxide that does not have a clear crystalline state (that is, is in an amorphous state) in the diffraction spectrum obtained by the powder X-ray diffraction method. Among the above, the glass layer is preferably silica glass.

[0080] - Lubricant S - The lubricant S is interposed between the inner peripheral surface of the pressure belt 62 and the sliding member. Examples of the lubricant S include grease, silicone oil (e.g., dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, sulfonic acid-modified silicone oil, etc.), fluorine oil (e.g., fluorosilicone oil, perfluoropolyether oil, etc.). Among these, from the viewpoint of setting the viscosity of the lubricant within the range described below, it is preferable that the lubricant contains silicone oil, and it is more preferable that it contains long-chain alkyl-modified silicone oil (e.g., having 3 or more carbon atoms).

[0081] The lubricant may contain other additives (e.g., antioxidants, etc.).

[0082] The viscosity of the lubricant is 2 1000 mm 2 / s or less, preferably 2 50 mm 2 / s or more and 2 600 mm 2 / s or less, more preferably When the viscosity of the lubricant is within the above range, appropriate fluidity and retention are imparted, and it is easy for the lubricant to be interposed between the inner peripheral surface of the second rotating body and the pressing member. Also, even when a scratch or the like occurs on the inner peripheral surface of the second rotating body, it is easy for the lubricant to fill the portion where the scratch or the like has occurred.

[0083] The method for setting the viscosity of the lubricant within the above range is not particularly limited. For example, a method of using long-chain alkyl-modified silicone oil in which the side chain has a low molecular weight and the intermolecular interaction is relatively low and adjusting the molecular weight of the main chain can be mentioned.

[0084] The viscosity of the lubricant is the viscosity at room temperature (23 °C) and is measured by a rotational viscometer Rheomat 115 (manufactured by Contraves).

[0085] Lubricant S may contain other components in addition to oil. Examples of other components include grease (such as silicone grease), heat conductive agents, antioxidants, surfactants, silicone particles, organic metal salts, hindered amines, and the like.

[0086] (Image forming operation of the image forming apparatus) Hereinafter, the image forming operation of the image forming apparatus according to the present embodiment will be described. Note that the image forming operation will be described by taking as an example the operation of forming a yellow image in the first process cartridge 10Y.

[0087] First, prior to the image forming operation, the surface of the photoreceptor 1Y is charged to a potential of, for example, about -600 V by the charging roller 2Y.

[0088] The photoreceptor 1Y is formed by laminating a photosensitive layer on, for example, a conductive substrate. This photosensitive layer is usually, for example, highly resistant, but has the property that when irradiated with the laser beam 3Y, the specific resistance of the portion irradiated with the laser beam changes. Therefore, according to the yellow image data sent from a control unit (not shown), the laser beam 3Y is output via the exposure device 3 onto the surface of the charged photoreceptor 1Y. The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic latent image of the yellow printing pattern on the surface of the photoreceptor 1Y.

[0089] The electrostatic latent image thus formed on the photoreceptor 1Y is rotated to the developing position as the photoreceptor 1Y travels. Then, at this developing position, the electrostatic latent image on the photoreceptor 1Y is visualized (toner image) by the developing device 4Y.

[0090] Inside the developing device 4Y, a developer containing, for example, yellow toner and carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres only to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y on which the yellow toner image is formed continues to travel, and the toner image developed on the photoreceptor 1Y is conveyed to the primary transfer position.

[0091] When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, and the toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (-) of the toner, and is, for example, controlled to a constant current of about +10 μA by a control unit (not shown) in the first process cartridge 10Y.

[0092] Also, the primary transfer biases applied to the primary transfer rollers 5M, 5C, 5K after the second process cartridge 10M are similarly controlled.

[0093] In this way, the intermediate transfer belt 20 onto which the yellow toner image is transferred by the first process cartridge 10Y is sequentially conveyed through the second to fourth process cartridges 10M, 10C, 10K, and the toner images of each color are similarly overlapped and multi-transferred.

[0094] The intermediate transfer belt 20 on which toner images of all colors are multiply transferred through the first to fourth process cartridges reaches a secondary transfer unit composed of the intermediate transfer belt 20, a support roller 24 in contact with the inner peripheral surface of the intermediate transfer belt 20, and a secondary transfer roller (an example of a secondary transfer device) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording medium P is fed between the secondary transfer roller 26 and the intermediate transfer belt 20 via a feeding mechanism, and a secondary transfer bias is applied to the support roller 24. The transfer bias applied at this time has a (-) polarity that is the same polarity as the polarity of the toner ( - ), and an electrostatic force directed from the intermediate transfer belt 20 toward the recording medium P acts on the toner image, and the toner image on the intermediate transfer belt 20 is transferred onto the recording medium P. Incidentally, the secondary transfer bias at this time is determined according to the resistance detected by resistance detection means (not shown) that detects the resistance of the secondary transfer unit, and is controlled at a constant voltage. Note that the intermediate transfer belt 20, the primary transfer roller 5Y, and the secondary transfer roller 26 correspond to an example of a transfer device.

[0095] Thereafter, the recording medium P is fed into the fixing device 28 and inserted into a contact area formed by the pressure roller 52 that is rotationally driven in the direction of the arrow and the pressure belt 62 being in pressure contact. At this time, the recording medium P is inserted so that the surface of the recording medium P on which the unfixed toner image is formed faces the surface of the pressure roller 52. When the recording medium P passes through this contact area, heat and pressure are applied to the recording medium P, whereby the unfixed toner image is fixed to the recording medium P. After passing through the contact area, the fixed recording medium is peeled off from the pressure roller 52 and discharged from the fixing device 28.

[0096] In this way, the fixing process is performed and permanently fixed onto the recording medium P. The recording medium P on which the fixing of the color image is completed is carried out toward the discharging unit, and a series of color image forming operations is terminated.

Example

[0097] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0098] <Production of the pressure belt> (Production of the pressure belt (1)) Shot blasting was performed at a shot blasting time per unit area of 1 min / mm 2 A silicone-based release agent was applied to the surface of an aluminum cylindrical core body having an uneven shape formed on its surface by shot blasting (bead diameter: 100 μm), and after baking treatment at 300 °C for 1 hour, an N-methylpyrrolidone solution containing a precursor of polyimide resin was dip-coated on this surface and dried at 100 °C for 1 hour. Thereby, a resin base material layer constituting the inner peripheral surface of the pressure belt was formed. Next, a fluororesin dispersion (specifically, a PTFE dispersion) was coated on the outer peripheral surface of the resin base material layer, and then, after drying at 60 °C for 10 minutes in a baking furnace, it was gradually heated to 380 °C, baked for 20 minutes, and then cooled to room temperature to form a release layer. Thereafter, the resin base material layer having the release layer formed thereon was removed from the core body and cut into a desired size by a cutting machine to obtain the pressure belt (1).

[0099] (Production of the pressure belt (2)) The shot blasting time per unit area was set to 5 min / mm 2 A pressure belt was obtained in the same manner as in the production of the pressure belt (1), except that the surface roughness of the aluminum cylindrical core body having an uneven shape formed on its surface by shot blasting was adjusted.

[0100] (Production of the pressure belt (3)) The shot blasting time per unit area was set to 0 min / mm 2 A pressure belt was obtained in the same manner as in the production of the pressure belt (1), except that the surface roughness of the aluminum cylindrical core body having an uneven shape formed on its surface by shot blasting was adjusted.

[0101] (Production of the Pressurized Belt (4)) A pressurized belt was obtained in the same manner as the production of the pressurized belt (1), except that 30 parts of SiC particles were added to the polyimide precursor solution (Fujimi Incorporated).

[0102] (Production of the Pressurized Belt (5)) A pressurized belt was obtained in the same manner as the production of the pressurized belt (1), except that 15 parts of SiC particles were added to the polyimide precursor solution (Fujimi Incorporated).

[0103] (Production of the Sliding Member) (Production of the Sliding Member (1)) On an alumina substrate, a resistive heating part made of stainless steel was printed and fired at 850 degrees. Then, after measuring the resistance value, a pair of electrodes were printed and further fired at 850 degrees. Subsequently, the surface was coated with silica glass so as to cover the electrodes and the resistive heating part, fired at 850 degrees, and then fired again at 870 degrees. Thereafter, the surface was ground using sandpaper with a particle size of 0.1 μm until the load length ratio Rmr became the value shown in Table 1, and a sliding member that is a planar heating element was obtained.

[0104] (Production of the Sliding Member (2)) A sliding member that is a planar heating element was obtained in the same manner as the production of the sliding member (1), except that the re-firing temperature after coating the surface with silica glass was set to 950 °C.

[0105] (Production of the Sliding Member (3)) A sliding member that is a planar heating element was obtained in the same manner as the production of the sliding member (1), except that the re-firing temperature after coating the surface with silica glass was set to 600 °C.

[0106] (Production of the Sliding Member (4)) A sliding member that is a planar heating element was obtained in the same manner as the production of the sliding member (1), except that the processing time with sandpaper was doubled.

[0107] (Manufacture of the sliding member (5)) A sliding member that is a planar heating element was obtained by the same method as the manufacture of the sliding member (1), except that the processing time with sandpaper was set to 0.75 times.

[0108] (Manufacture of the sliding member (6)) A sliding member that is a planar heating element was obtained by the same method as the manufacture of the sliding member (1), except that the re-firing temperature after coating the surface with silica glass was set to 870°C, then cooled and fired again at 870°C.

[0109] (Manufacture of the sliding member (7)) A sliding member that is a planar heating element was obtained by the same method as the manufacture of the sliding member (1), except that silica glass was used as the toughened glass (product name: Pandra King, manufacturer: Xuhong).

[0110] (Manufacture of the sliding member (8)) A sliding member that is a planar heating element was obtained by the same method as the manufacture of the sliding member (1), except that electroless nickel plating was formed on the glass surface.

[0111] (Manufacture of the sliding member (9)) Polyetheretherketone resin (PEEK) (Victrex 450G (manufactured by Victrex)) was melted by heating at 380°C in a twin-screw extrusion melt kneader (twin-screw melt kneading extruder L / D60 (manufactured by Parker Corporation)), supplied from the side of the kneader using a side feeder, melt-kneaded, the kneaded melt was put into a water tank for cooling and solidification, cut into the desired size, and mixed resin pellets containing silicone resin particles were obtained. The obtained mixed resin pellets were put into a single-screw extrusion device, and the melted mixed resin was extruded in a sheet shape from a T-die mold (melt discharge gap: 200 μm) heated to 380°C and wound around a cooling roll at 190°C for cooling. This cooled sheet was shaped at 400°C and 10 Mpa pressure using a roll with a 100-mesh SUS wire mesh wound around its surface to obtain a concavo-convex sheet. The concavo-convex sheet was cut into a predetermined size to obtain the sliding member (8).

[0112] (Fabrication of the sliding member (10)) A sliding member, which is a planar heating element, was obtained by the same method as the fabrication of the sliding member (1), except that the re-firing temperature after coating the surface with silica glass was set to 600 °C and the processing time with sandpaper was set to 1.5 times.

[0113] (Fabrication of the sliding member (11)) A sliding member, which is a planar heating element, was obtained by the same method as the fabrication of the sliding member (1), except that the processing time with sandpaper was set to 0.9 times.

[0114] The ten-point average roughness of the sliding surface of each sliding member was measured based on the JIS B-0601 standard. The results are shown in Table 1. Also, the following properties obtained by the above-described measurement method are summarized and shown in Table 1. · Surface roughness Ra1 of the sliding surface of the sliding member · Load length ratio Rmr of the sliding surface of the sliding member · Surface roughness Ra2 of the inner peripheral surface of the second rotating body · Hardness A of the sliding surface of the sliding member · Hardness B of the inner peripheral surface of the second rotating body · Difference (Surface roughness Ra1 of the sliding surface of the sliding member - Surface roughness Ra2 of the inner peripheral surface of the second rotating body) · Difference (Hardness A of the sliding surface of the sliding member - Hardness B of the inner peripheral surface of the second rotating body) · Viscosity of the lubricant

[0115] <Lubricant> · Lubricant (1): Long-chain alkyl-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name KF-4003) · Lubricant (2): Fluoroalkyl-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name FL-100-1000CS) · Lubricant (3): Long-chain alkyl-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name KF-4917)

[0116] <Examples 1 to 17, Comparative Examples 1 to 6> With the combinations shown in Table 1, a pressure belt, a sliding member, and a lubricant were installed in the fixing device of the image forming apparatus "Refurbished APEOS PORT PrintC5570" manufactured by Fuji Film Business Innovation Co., Ltd.

[0117] Using this apparatus as the image forming apparatus for each example, the following evaluations were carried out.

[0118] <Evaluation: Presence or absence of scratches on the inner peripheral surface of the pressure belt> A solid image (blue solid 100% density) was continuously output on A4 paper at 1000 kPV. Then, the pressure belt was removed from the image forming apparatus, and scratches on a 100 mm × 100 mm width area of the inner peripheral surface of the pressure belt were visually evaluated according to the following criteria. A: No scratches B: One or more and ten or fewer scratches can be confirmed C: Ten or more and fifty or fewer scratches can be confirmed D: Fifty or more scratches can be confirmed

[0119] <Evaluation: Torque increase of the pressure belt> Regarding the torque increase of the pressure belt, it was measured as follows. The measuring gear of a direct torque meter (a device manufactured in-house by Fuji Film Business Innovation Co., Ltd.) was fitted to the gear part of the fixing roll, and the value A0 of the torque at the initial drive of the fixing roll and the value A of the torque required when driven at 100 kPV 100 were measured (unit: Nm). The drive torque increase (A0 - A 100 ) of this fixing roll was evaluated as the torque increase value of the pressure belt. If the drive torque increases too much, the drive gear of the fixing roll, which is the drive source, will be burdened, resulting in practical problems. In particular, as phenomena indicating malfunctions, paper wrinkles occur on the paper for obtaining images, or abnormal noises of the gear occur. In the comparative example, the number of paper outputs (kPV = 1000 × number of paper outputs) when the drive torque reached 0.9 N·m is shown.

[0120]

Table 1

[0121] From the above results, it was found that the fixing device of this embodiment suppresses wear and scratches on the inner peripheral surface of the pressure belt (second rotating body) and suppresses an increase in the torque of the pressure belt as compared with the fixing device of the comparative example.

[0122] This embodiment includes the following aspects. ((1)) A first rotating body, A second rotating body disposed in contact with the first rotating body, A pressing member disposed on the inner peripheral surface of the second rotating body and pressing the second rotating body against the first rotating body from the inner peripheral surface of the second rotating body, A sliding member interposed between the inner peripheral surface of the second rotating body and the pressing member, A lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member, Comprising The sliding member has a sliding surface with irregularities, a surface roughness Ra1 of 0.20 μm or more, and a load length ratio Rmr of 35% or more, and is a fixing device. ((2)) The fixing device according to ((1)), wherein the surface roughness Ra1 is 0.20 μm or more and 5.00 μm or less. ((3)) The fixing device according to ((1)) or ((2)), wherein the load length ratio Rmr is 36% or more and 75% or less. ((4)) The fixing device according to any one of ((1)) to ((3)), wherein the sliding member has a planar heating element. ((5)) The fixing device according to ((4)), wherein the sliding member has a glass layer on the sliding surface. ((6)) The surface roughness Ra1 of the sliding surface of the sliding member is A value smaller than the surface roughness Ra2 of the inner peripheral surface of the second rotating body, and is the fixing device according to any one of ((1)) to ((5)). ((7)) The surface roughness Ra1 of the sliding surface of the sliding member and The fixing device according to the above ((6)), wherein the difference (Ra1 - Ra2) from the surface roughness Ra2 of the inner peripheral surface of the second rotating body is 0.05 μm or more and 2.00 μm or less. ((8)) The hardness A of the sliding surface of the sliding member is higher than the hardness B of the inner peripheral surface of the second rotating body, and the fixing device according to any one of the above ((1)) to ((7)). ((9)) The difference (A - B) between the hardness A of the sliding surface of the sliding member and the hardness B of the inner peripheral surface of the second rotating body is 10 or more and 600 or less, and the fixing device according to the above ((8)). ((10)) The lubricant is 20 mm 2 / s or more and 1000 mm 2 / s or less, and the fixing device according to any one of the above ((1)) to ((9)). ((11)) An image carrier, a latent image forming device that forms a latent image on the surface of the image carrier, a developing device that develops the latent image into a toner image using a developer, a transfer device that transfers the toner image developed on the recording medium, the fixing device according to any one of the above ((1)) to ((10)) that fixes the toner image on the recording medium, and an image forming apparatus comprising the same.

[0123] According to the invention according to ((1)), in a specific fixing device, when the surface roughness Ra1 of the sliding surface of the sliding member is less than 0.20 μm, or when the load length ratio Rmr of the sliding surface of the sliding member is less than 35%, a fixing device is provided in which scratches on the inner peripheral surface of the fixing member are reduced. According to the invention according to ((2)), in a specific fixing device, a fixing device is provided in which scratches on the inner peripheral surface of the fixing member are reduced as compared with the case where the surface roughness Ra1 is less than 0.20 μm or more than 5.00 μm. According to the invention according to ((3)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the load length ratio Rmr is less than 36% or more than 75%. According to the invention according to ((4)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the sliding member is a pressure member having no heater. According to the invention according to ((5)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the sliding member does not have a glass layer on the outermost surface on the pressure member side. According to the invention according to ((6)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the surface roughness Ra1 of the sliding surface of the sliding member is larger than the surface roughness Ra2 of the inner peripheral surface of the second rotating body. According to the invention according to ((7)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the difference (Ra1 - Ra2) between the surface roughness Ra1 of the sliding surface of the sliding member and the surface roughness Ra2 of the inner peripheral surface of the second rotating body is less than 0.05 μm or more than 2.00 μm. According to the invention according to ((8)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the hardness A of the sliding surface of the sliding member is lower than the hardness B of the inner peripheral surface of the second rotating body. According to the invention according to ((9)), a fixing device is provided in which, in a specific fixing device, the damage to the inner peripheral surface of the fixing member is reduced as compared with the case where the difference (A - B) between the hardness A of the sliding surface of the sliding member and the hardness B of the inner peripheral surface of the second rotating body is 10 or more and 600 or less. According to the invention according to ((10)), in a specific fixing device, when the viscosity of the lubricant is less than 20 mm 2 / s or more than 1000 mm 2 / s, a fixing device is provided in which the damage to the inner peripheral surface of the fixing member is reduced as compared with the case. According to the invention related to ((11)), there is provided an image forming apparatus including a fixing device that reduces scratches on the inner peripheral surface of a fixing member as compared with an image forming apparatus including a fixing device in which the sliding surface roughness Ra1 of a sliding member is less than 0.20 μm or the load length ratio Rmr of the sliding surface of the sliding member is less than 35%.

Explanation of Signs

[0124] 1Y, 1M, 1C, 1K Photoreceptor 2Y, 2M, 2C, 2K Charging Roller 3Y, 3M, 3C, 3K Laser Beam 3 Exposure Device 4Y, 4M, 4C, 4K Developing Device 5Y, 5M, 5C, 5K Primary Transfer Roller 6Y, 6M, 6C, 6K Photoreceptor Cleaning Device 10Y, 10M, 10C, 10K Process Cartridge 20 Intermediate Transfer Belt 20a Intermediate Transfer Body Cleaning Device 22 Driving Roller 24 Support Roller 26 Secondary Transfer Roller 28 Fixing Device 52 Pressing Roll 54 Shaft Portion 56 Elastic Body Layer 58 Release Layer 60 Fixing Device 62 Pressing Belt 64 Planar Heating Element 68 Pressing Member 72 Frame Member 90 Inner Peripheral Surface of Pressing Belt 62 100 Image Forming Apparatus P Recording Medium S Lubricant R1 Arrow Direction R2 Arrow Direction

Claims

1. A first rotating body, a second rotating body disposed in contact with the first rotating body, a pressing member disposed on the inner peripheral surface of the second rotating body to press the second rotating body against the first rotating body from the inner peripheral surface of the second rotating body, a sliding member interposed between the inner peripheral surface of the second rotating body and the pressing member, a lubricant interposed between the inner peripheral surface of the second rotating body and the sliding member, and comprising a fixing device in which the sliding member has an uneven sliding surface with a surface roughness Ra1 of 0.20 µm or more and a load length ratio Rmr of 35% or more.

2. The fixing device according to claim 1, wherein the surface roughness Ra1 is 0.20 µm or more and 5.00 µm or less.

3. The fixing device according to claim 1, wherein the load length ratio Rmr is 36% or more and 75% or less.

4. The fixing device according to claim 1, wherein the sliding member has a planar heating element.

5. The fixing device according to claim 4, wherein the sliding member has a glass layer on the sliding surface.

6. The surface roughness Ra1 of the sliding surface of the sliding member is a value smaller than the surface roughness Ra2 of the inner peripheral surface of the second rotating body. The fixing device according to claim 1.

7. The difference (Ra1 - Ra2) between the surface roughness Ra1 of the sliding surface of the sliding member and the surface roughness Ra2 of the inner peripheral surface of the second rotating body is 0.05 µm or more and 2.00 µm or less. The fixing device according to claim 6.

8. The hardness A of the sliding surface of the sliding member is a value higher than the hardness B of the inner peripheral surface of the second rotating body. The fixing device according to claim 1.

9. The difference (A - B) between the hardness A of the sliding surface of the sliding member and the hardness B of the inner peripheral surface of the second rotating body is 10 or more and 600 or less. The fixing device according to claim 8.

10. The viscosity of the lubricant is 20 mm ２ / s or more and 1000 mm ２ / s or less, the fixing device according to claim 1.

11. An image carrier, a latent image forming device for forming a latent image on the surface of the image carrier, a developing device for developing the latent image into a toner image using a developer, a transfer device for transferring the toner image developed on the recording medium, and a fixing device according to any one of claims 1 to 10 for fixing the toner image on the recording medium, and an image forming apparatus comprising the same.

Images