Fixing apparatus and image forming apparatus

Abstract

In an image forming apparatus, the lifespan of the fixing belt is maintained over a long period of time without removing the coating layer of the friction member while retaining the lubricant. [Solution] A fixing device comprising: an endless belt having an outer surface layer and a base material having an inner surface; a rotating body that contacts the surface layer of the endless belt; a sliding member that contacts the inner surface of the endless belt; a pressing member that presses the endless belt toward the rotating body via the sliding member; and a heating source that heats the endless belt, wherein a lubricant is present between the sliding member and the endless belt, the arithmetic mean roughness of the inner surface of the endless belt is 0.03 μm or more and 0.30 μm or less, and the Martens hardness H1 of the sliding member and the Martens hardness H2 of the inner surface of the endless belt are equal to H1

Description

Technical Field

[0001] The present invention relates to a fixing device used for heat fixing of an electrophotographic image forming apparatus, and an image forming apparatus using the fixing device.

Background Art

[0002] In recent years, the on-demand printing market has been expanding, which prints commercial printed materials such as catalogs, posters, and pamphlets according to the required number of copies, and continuously prints while changing part of the printed content of various invoices and direct mails for each customer. These days, electrophotographic image forming apparatuses responsible for on-demand printing are required to speed up the printing time. In order to achieve high-speed printing, for example, the development of a fixing device using a wide nip (wide nip) as a fixing nip used when fixing a toner image on a recording medium has been considered. In a fixing device having a wide nip, in order to guarantee excellent image quality for the recording medium, it is essential to prevent slip between the belt member and the recording medium and between the pressure member and the recording medium in the nip forming portion. That is, it is necessary to make the frictional force between the backup member and the inner peripheral surface of the belt member sufficiently smaller than the frictional force between the recording medium and the belt member and the frictional force between the recording medium and the pressure member.

[0003] For the purpose of reducing the frictional force between the backup member and the belt member, Patent Document 1 proposes a system using a rubbing member between the backup member and the belt member. In addition, the surface material and surface shape of the rubbing member for minimizing the coefficient of friction of the rubbing member surface have been proposed. For example, in the configuration disclosed in Patent Document II, a low-friction material is used for the material of the rubbing member surface, and the coefficient of friction of the rubbing member is reduced by creating irregularities on the surface shape. Further, as disclosed in Patent Document 3, when a lubricant is applied to the inner peripheral surface of the fixing belt to further improve the slidability, a technique for increasing the roughness of the inner peripheral surface of the belt to improve the retention of the lubricant is also known.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-181948 [Patent Document 2] Japanese Patent Publication No. 2008-275927 [Patent Document 3] Japanese Patent Publication No. 2016-050960 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the technologies disclosed in Patent Documents 1 to 3 have the following problems. When increasing the roughness of the inner surface of the fixing belt to improve the sliding properties between the fixing belt and the pressing member, if the material hardness of the fixing belt is greater than that of the coating layer, there is a risk of damaging the coating layer. In such cases, sliding properties will decrease, and the increased torque is likely to shorten the lifespan of the heating fixing device. Furthermore, if the roughness of the inner surface of the anchoring belt is reduced to prevent the coating layer from being worn away, the retention of the lubricant on the inner surface of the belt decreases, making it difficult to obtain a sufficient oil film thickness, which again increases the likelihood of a shortened lifespan.

[0006] In view of these circumstances, the present invention aims to provide a fixing device or image forming apparatus that can maintain the lifespan of the fixing belt over a long period of time without removing the coating layer of the sliding member while retaining the lubricant. [Means for solving the problem]

[0007] To solve the above problems, a fixing device according to one aspect of the present invention is provided. An endless belt having a surface layer which is an outer layer and a base material which has an inner circumferential surface, A rotating body that comes into contact with the surface of the endless belt, A friction member that contacts the inner circumferential surface of the endless belt, A fixing device having a pressing member that presses the endless belt toward the rotating body through the rubbing member, and a heating source that heats the endless belt. A lubricant is present between the rubbing member and the endless belt. The arithmetic mean roughness of the inner peripheral surface of the endless belt is 0.03 μm or more and 0.30 μm or less. The martensite hardness H1 of the rubbing member and the martensite hardness H2 of the inner peripheral surface of the endless belt satisfy H1 < H2.

Advantages of the Invention

[0008] According to one aspect of the present invention, it is possible to maintain the life of the fixing belt for a long time without scraping the coat layer of the rubbing member while holding the lubricant.

Brief Description of the Drawings

[0009] [Figure 1] It is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] It is a schematic cross-sectional view of a fixing device according to an embodiment. [Figure 3] It is a diagram showing details of a sliding member in the fixing device shown in FIG. 2. [Figure 4] It is a schematic cross-sectional view of a fixing belt according to an embodiment.

Modes for Carrying Out the Invention

[0010] Hereinafter, a preferred embodiment of an image forming apparatus according to the present invention will be described based on the drawings. In the following, an example in which the present invention is applied to a full-color electrophotographic image forming apparatus having a plurality of photosensitive drums will be described, but the present invention is not limited to this and can also be applied to various types of image forming apparatuses, monochromatic image forming apparatuses, and the like.

[0011] Furthermore, in the following description, components common to multiple drawings are denoted by the same reference numeral. Therefore, the common components are explained by referring to multiple drawings, and the explanation of components denoted by the same reference numeral is omitted as appropriate. In addition, the dimensions, materials, shapes, and relative positions of components shown in the following embodiments and examples are arbitrary and can be changed according to the configuration of the device to which the present invention is applied or various conditions.

[0012] <Image forming apparatus> First, the schematic configuration of an image forming apparatus according to one embodiment of the present invention will be explained using Figure 1. Figure 1 shows a full-color image forming apparatus according to this embodiment. The image forming apparatus 1 comprises an image reading unit 2 and an image forming apparatus body 3. The image reading unit 2 reads a document placed on the document glass 21. Light emitted from a light source 22 is reflected by the document and formed on a CCD sensor 24 via an optical system component 23 such as a lens. By scanning in the direction of the arrow, the reader control unit 25 uses the output from the CCD sensor 24 to convert the document into a line-by-line electrical signal data sequence. The image signal generated by the reader control unit 25 is sent to the image forming apparatus body 3, where the control unit 30 performs image processing according to each image forming unit, which will be described later. The control unit 30 can also receive external input as an image signal from an external host device (not shown), such as a print server.

[0013] The image forming apparatus main body 3 includes a plurality of image forming units Pa, Pb, Pc, and Pd. In each image forming unit, image formation is performed based on the above-described image signal. That is, the image signal is converted into a laser beam that is PWM (pulse width modulation) controlled by the control unit 30. In FIG. 1, the polygon scanner that functions as the exposure device 31 scans the laser beam according to the image signal. Then, the laser beam is irradiated onto the photosensitive drums 200a to 200d as the image carriers of the respective image forming units Pa to Pd. Note that Pa is a yellow (Y) image forming unit, Pb is a magenta (M) image forming unit, Pc is a cyan (C) image forming unit, and Pd is a black (Bk) image forming unit, which form images of the corresponding colors. Since the structures of the image forming units Pa to Pd are substantially the same, the details of the Y image forming unit Pa will be described below, and the description of the other image forming units will be omitted. In the Y image forming unit Pa, 200a is a photosensitive drum, and a toner image is formed on the surface of the photosensitive drum based on the image signal as described below. The image forming apparatus 1 can perform an image forming operation according to an instruction from the operation unit 4 or an external host device (not shown).

[0014] The Y image forming unit Pa includes a photosensitive drum 200a, a primary charger 201a, a developing device 202a, a transfer roller 203a, and a cleaner 207a. Further, as a configuration shared by each image forming unit, an intermediate transfer belt 204 and a secondary transfer roller pair 205, 206 are provided.

[0015] The primary charger 201a charges the surface of the photosensitive drum 200a to a predetermined potential to prepare for electrostatic latent image formation. Subsequently, an electrostatic latent image is formed on the surface of the photosensitive drum 200a charged to the predetermined potential by a laser beam from a polygon scanner (exposure device 31). The developing unit 202a develops the electrostatic latent image on the photosensitive drum 200a to form a toner image and functions as a toner image forming unit in the present invention. The transfer roller 203a discharges from the back of the intermediate transfer belt 204 and applies a primary transfer bias of the opposite polarity to the toner, and transfers the toner image on the photosensitive drum 200a onto the intermediate transfer belt 204. The intermediate transfer belt 204 functions as an intermediate transfer unit onto which the toner image is transferred from the photosensitive drum 200a in the present invention. After transfer, the surface of the photosensitive drum 200a is cleaned by the cleaner 207a.

[0016] The toner image on the intermediate transfer belt 204 is conveyed to the next image forming unit, and in the order of Y, M, C, and Bk, the toner images of each color formed in each image forming unit are sequentially transferred, and a four-color image is formed on its surface. The toner image that has passed through the Bk image forming unit is secondarily transferred to the paper by applying a secondary transfer electric field of the opposite polarity to the toner image on the intermediate transfer belt 204 in the secondary transfer unit composed of the secondary transfer roller pair 205 and 206. The paper fed from the paper cassette 8 or the paper cassette 9 is conveyed with the timing of paper feeding controlled to align the position of the toner image on the intermediate transfer belt 204.

[0017] Thereafter, the toner image on the paper is fixed to the paper by the fixing device F as an image heating device. The fixing device F fixes the transferred toner image to a recording medium such as paper. After passing through the fixing device, the paper on which the toner image is fixed is discharged outside the machine. When the image printing is a duplex job, when the transfer and fixing of the toner on the first side (the first side) of the image formation are completed, the paper is reversed in front and back through the reversing unit provided inside the image forming apparatus after fixing. Subsequently, the transfer and fixing of the toner on the second side (the second side) of the image formation are executed, and then it is discharged outside the machine and stacked on the discharge tray 7.

[0018] Next, using Figure 2, a specific example of the configuration of the fixing device F in one embodiment of the present invention will be described.

[0019] <Fusing device> Figure 2 shows a schematic diagram of the overall configuration of a belt heating type fixing device F according to one embodiment of the present invention. In the figure, the X direction corresponds to the transport direction of the recording material (corresponding to the aforementioned paper, not shown in the figure), the Y direction corresponds to the paper width direction, and the Z direction corresponds to the pressurization direction. The dotted line in Figure 2 represents an enlarged cross-section of the nip section N.

[0020] The fixing device F comprises a fixing belt (hereinafter referred to as the belt) 301, a stay 302, a pressure pressing member (hereinafter referred to as the pressing member) 303, a friction member 304, a pressure roller 305, a heater 306, and a heating roller 307. The belt 301 functions as an endless, rotatable heating rotating body. The pressing member 303 is supported by the stay 302. The friction member 304 is positioned to cover the pressing member 303, and the belt 301 is stretched between the friction member 304 and the heating roller 307. The pressure roller 305 faces the belt 301 and functions as a pressure rotating body that forms a nip portion N together with the belt 301.

[0021] The belt 301 has thermal conductivity and heat resistance, and has a thin-walled cylindrical shape. In this embodiment, the belt 301 has a three-layer structure consisting of a base layer 301a, an elastic layer 301b provided on the outer circumference of the base layer 301a, and a release layer 301c provided on the outer circumference of the release layer. The base layer 301a is 80 μm thick and is formed mainly of polyimide resin (PI). The elastic layer 301b is 300 μm thick and is formed mainly of silicone rubber. The release layer 301c is 30 μm thick and is formed mainly of fluororesin, and is particularly formed using PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin). The outer diameter of the belt 301 is 150 mm. It should be noted that the belt 301 is not limited to the three-layer structure exemplified here. For example, a sliding layer may be provided inside the base layer 301a in the portion that comes into contact with the abrasive member 304 and the heating roller 307, which will be described later.

[0022] The pressing member 303 is pressed against the pressure roller 305 with the belt 301 in between. The pressing member 303 is made of LCP (liquid crystal polymer) resin. In this embodiment, a friction member 304 is interposed between the pressing member 303 and the belt 301.

[0023] The detailed configuration of the abrasive member 304 is shown in Figure 3. Figure 3 shows the cross-sectional structure when the abrasive member 304 is cut in the conveying direction. As shown in Figure 3, the abrasive member 304 according to this embodiment is composed of a base layer 304a and a coating layer 304b. The base layer 304a only needs to have sufficient strength and heat resistance, and the material is preferably SUS, copper, aluminum, or engineering plastic (PI, PEEK, LCP, etc.). In this embodiment, SUS with a thickness of 1.3 mm was used. The coating layer 304b is preferably formed from a fluorine coating, PTFE, PFA, etc. in order to achieve low friction. In this embodiment, PTFE (polytetrafluoroethylene) with a thickness of 20 μm was used for coating. By further applying a lubricant to the inner circumferential surface of the belt 301, the belt 301 is configured to slide smoothly against the abrasive member 304. Silicone oil was used as the lubricant.

[0024] In this embodiment, a stay 302 is used to supplement the strength of the pressing member 303. In this embodiment, the base layer 304a is provided with a coating layer 304b, but a configuration in which an adhesive layer is provided between the base layer 304a and the coating layer 304b is also acceptable. By using an adhesive layer, when a metal material such as SUS, copper, or aluminum is used as the base layer 304a, it is possible to achieve good adhesive strength between the base layer 304a and the coating layer 304b.

[0025] In this embodiment, the abrasive member 304 is configured to cover the pressing member 303 both inside and outside the nip portion N. However, the form of the abrasive member 304 is not limited to the example of this embodiment, and it is acceptable for only a part of the nip portion N to be covered by the abrasive member 304. In other words, it is acceptable for the abrasive member 304 to be placed only on the nip portion N. Also, in this embodiment, the coating layer 304b is formed over the entire abrasive member 304. However, the form of the coating layer 304b is not limited to the example of this embodiment, and it is acceptable for only a part of the nip portion N to be covered by the coating layer 304b. In other words, it is acceptable for the coating layer 304b to be placed only on the nip portion N. Furthermore, the surface of the base layer 304a or the coating layer 304b can be embossed, which can improve the retention of silicone oil on the surface of the coating layer 304b.

[0026] In this embodiment, a configuration is adopted in which the abrasive member 304 is fixed to the stay 302. However, the relationship between the abrasive member 304 and the stay 302 is not limited to the example given here, and a configuration in which they are not fixed is also possible. Furthermore, the abrasive member 304 may be integrated with the pressing member 303. Also, a part of the abrasive member 304 may be fixed to the stay 302 or the pressing member 303. For example, both ends of the abrasive member 304 in the Y direction (paper width direction) may be fixed to the pressing member 303 with screws or the like.

[0027] In this embodiment, the heating roller 307 is made of a stainless steel pipe with a thickness of 1 mm, and a heater 306, such as a halogen heater, is disposed inside it as a heat source. With this configuration, the heating roller 307 can generate heat up to a predetermined temperature. The belt 301 is heated by the heating roller 307.

[0028] The heating roller 307 has a pivot point at one end or near the center, and rotates relative to the belt 301 to generate a tension difference between the front and back of the contact portion, thereby controlling the position of the belt 310 in the main scanning direction. Furthermore, the heating roller 307 is biased away from the pressure roller 305 by a spring supported by a frame (not shown) that rotatably supports the heating roller 307, and also functions as a tension roller that applies a predetermined tension to the belt 301.

[0029] In this embodiment, the pressure roller 305 is composed of a core metal layer 305c, an elastic layer 305b disposed on the outer circumference of the core metal layer 305c, and a release layer 305a further disposed on the outer circumference. In this embodiment, a SUS member with a diameter of 72 mm is used for the core metal layer 305c which is the shaft, conductive silicone rubber with a thickness of 8 mm is used for the elastic layer 305b, and fluororesin with a thickness of 100 μm is used for the release layer 305a. More specifically, PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin) is used as the fluororesin for the release layer 305a. The pressure roller 305 is axially supported by a fixing frame (not shown) of the fixing device F, and a gear is fixed to one end of it, which is connected to a drive source (not shown) via the gear to rotate it.

[0030] Next, we will describe an example in which a belt 301, abrasive member 304, etc., were specifically fabricated in the above-described embodiment and evaluated using them as a heating and fixing device in an image forming apparatus. Below, we will first describe the evaluation conditions for actually evaluating the belt 301. Then, we will describe the various conditions under which the belt 301 was manufactured and the method for measuring the characteristics of the obtained belt 301, and show the post-evaluation results of the belt 301 obtained in each embodiment in a table.

[0031] (Evaluation method) Next, we will describe the evaluation methods performed on each belt obtained as an embodiment of the present invention using each of the manufacturing methods described below.

[0032] (Evaluation 1: Coat wear evaluation) The wear of the coating layer 304b of the abrasive member 304 was evaluated. Specifically, the degree of abrasion of the coating layer 304b was evaluated. The evaluation conditions were as follows. Test environment: Room temperature 23°C, humidity 50% Process speed (belt travel speed): 500 mm / sec Print speed (pages printed per minute): 100 pages / minute Paper feeding conditions: A grid image is formed on GF-C081 (manufactured by Nippon Paper Industries Co., Ltd., 81g paper, A4 size), and the paper is fed continuously. Under the above conditions, the surface of the friction element 304 was observed under a microscope every 100,000 sheets of paper passed through, and the area ratio of the coating layer 304b covering the base material layer 304a was calculated. Based on the number of prints at which this area ratio was 40% or less, a ranking was assigned according to the following criteria. Ranks D and below were evaluated as NG (Not Good). (Evaluation Criteria) Rank A: Over 1 million cards with a coated surface area of ​​40% or more. Rank B: Over 800,000 cards and over 40% of the card's surface area covered by the coating layer. Rank C: Over 600,000 cards and over 40% of the card's surface area covered by the coating layer. Rank D: Less than 600,000 cards sold, with a coating area of ​​40% or less.

[0033] (Rating 2: Oil depletion rating) The depletion state of the oil (silicone oil in this example) used in the coating layer 304b, which is placed between the belt 301 and the friction member 304, was evaluated. The evaluation conditions are as follows. Test environment: Room temperature 23°C, humidity 50% Process speed: 500 mm / sec Print speed: None (no paper feed) Under the above conditions, the motor was run idle without feeding paper, and the torque of the motor that rotated the heating roller 307 was ranked according to the following criteria based on the time it took for the torque to exceed a predetermined value. In this device, the predetermined value was set to 2.0 kg·m, and ranks D or lower were evaluated as NG (Not Good). (Evaluation Criteria) A: Torque is below the specified value at 600h B: Torque is below the specified value in 500h C:400h: Torque is below the specified value. D:400h Torque exceeds specified value

[0034] (Evaluation 3: Retention Evaluation) The fixation of toner images was evaluated. The evaluation conditions were as follows: Test environment: Room temperature 23°C, humidity 50% Process speed: 500 mm / sec Print speed: 100 pages / minute Paper feeding conditions: A grid image is formed on GF-C081 (manufactured by Nippon Paper Industries Co., Ltd., 81g paper, A4 size), and 100 sheets are fed continuously. After that, the combined magenta and cyan toner concentration is 1.0 mg / cm². 2 The stacked GF-C081 sheets were passed through paper, and the resulting images were ranked based on the peeling width when folded, according to the following criteria. Ranks D and below were evaluated as NG (Not Good). (Evaluation Criteria) A: Toner peeling width is 0.4mm or less B: Toner peeling width is 0.8mm or less C: Toner peeling width is 1.0 mm or less D: Toner peeling width is greater than 1.0 mm

[0035] <Example 1> (Method of manufacturing fixing film) Next, the method for manufacturing the fixing device used in this embodiment will be described. The fixing rotating body belt 301 in the present invention has the cross-sectional shape shown in Figure 4. The belt 301 comprises a base layer 301a having an endless shape as described above, an elastic layer 301b provided on the outer peripheral surface of the base layer 301a, and a release layer 301c on the outer peripheral surface of the elastic layer 301b.

[0036] (1) Release layer The release layer 301c can be a fluororesin material containing tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and perfluoropolyether (PFPE), with a thickness of 100 μm or less, preferably 10 to 70 μm. Examples of fluororesin materials include PTFE and PFA used individually, as well as tetrafluoroethylene-hexafluoropropylene copolymer (FEP). The inner surface of the release layer 301c (the bonding surface with the elastic layer 301b) can be pre-treated with sodium, excimer laser, ammonia, or plasma etching to improve adhesion.

[0037] In this embodiment, a 20 μm thick PFA tube obtained by extrusion molding was used. The inner surface of the tube was subjected to plasma etching to improve wettability with the adhesive described later. However, a 50 μm thick extruded tube using 959HP-PLUS (manufactured by Mitsui Chemours Products Co., Ltd.) as pellets may be used as the release layer 301c, and the inner surface may be treated with sodium. In this case as well, it has been confirmed that the effects of the present invention can be obtained similarly, as described later. As mentioned above, the material of the release layer has been modified, but in this embodiment, based on the results of each embodiment and comparative example described later, it is presumed that the effect of the sum of the average roughness of the inner surface of the belt and the average roughness of the surface of the abrasive member is greater than the effect of this modification.

[0038] (2) Elastic layer The material of the elastic layer 301b is not particularly limited, and known materials used as elastic layers for fixing rotating bodies such as the belt 301 can be used. It is preferable that the elastic layer 301b contains silicone rubber, which has excellent heat resistance. Furthermore, addition-curing type liquid silicone rubber is preferably used as the raw material for the silicone rubber.

[0039] The thickness of the elastic layer 301b can be appropriately designed considering the surface hardness of the fixing rotating body and the width of the fixing nip portion to be formed. When the fixing rotating body is the belt 301 exemplified herein, the thickness of the elastic layer is preferably 100 μm or more and 3000 μm or less. By setting the thickness of the elastic layer 301b within this range, a sufficient width for the fixing nip can be ensured when the fixing rotating body is incorporated into the fixing device.

[0040] The elastic layer 301b may contain fillers. Fillers are added to control thermal conductivity, heat resistance, and elastic modulus. Specifically, non-conductive fillers include silicon carbide (SiC), silicon nitride (Si3N4), silica (SiO2), or boron nitride (BN). Other non-conductive fillers include aluminum nitride (AlN), alumina (Al2O3), iron oxide (Fe2O3), zinc oxide (ZnO), magnesium oxide (MgO), and titanium oxide (TiO2). The surface resistivity of the elastic layer in this case is 1 × 10⁻⁶. 14 It will be greater than Ωcm. Conductive fillers can also be used, but in that case the surface resistivity of the elastic layer will be 1 × 10⁻⁶. 14 A volume resistivity of Ωcm or higher is required. If the volume resistivity falls below this level, image defects will occur due to current leakage caused by filler aggregation.

[0041] Furthermore, the material constituting the elastic layer 301b may contain a reaction control agent (inhibitor) called an inhibitor to control the reaction initiation time. Known substances such as methyl vinyltetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxide can be used as reaction control agents. Furthermore, if the thickness of the elastic layer 301b is less than 100 μm, the surface deformation of the belt 301 and other components in the fixing device becomes small, resulting in insufficient conformability to the paper during transfer. This leads to insufficient heat conduction from the belt 301 and other components to the paper.

[0042] In this example, taking into consideration the above materials, a silicone rubber containing 30 vol% silica particles was used as the elastic layer 301b, with a thickness of 500 μm.

[0043] (3) Base layer The material of the base layer 301a is not particularly limited, and known materials used as base layers for fixing rotating bodies such as the belt 301 can be used. For example, metals and alloys such as aluminum, iron, stainless steel, and nickel, as well as heat-resistant resins such as polyimide, can be used. The thickness is not particularly limited, but from the viewpoint of strength, flexibility, and heat capacity, it is preferably 20 μm to 100 μm.

[0044] The outer surface of the base layer 301a may be subjected to a surface treatment to provide adhesion to the elastic layer 301b. The surface treatment can be one or more types of physical treatments such as blasting, lapping, and polishing, or chemical treatments such as oxidation, coupling agent treatment, and primer treatment.

[0045] When an elastic layer 301b containing silicone rubber is provided on the surface of the base layer 301a, it is preferable to apply a primer treatment to the surface of the base layer in order to improve the adhesion between the base layer and the elastic layer. Examples of primers used for the primer treatment include paints in which a silane coupling agent, silicone polymer, methyl siloxane hydrogenation, alkoxysilane, reaction-accelerating catalyst, and a coloring agent such as red iron oxide are appropriately blended and dispersed in an organic solvent. The primer can be appropriately selected depending on the material of the base layer 301a, the type of elastic layer 301b, or the form of the crosslinking reaction.

[0046] In particular, when the elastic layer 301b contains a large amount of unsaturated aliphatic groups, a primer containing hydrosilyl groups is preferably used to impart adhesion through reaction with the unsaturated aliphatic groups. Other types of primers include those containing alkoxy groups. Commercially available primers can also be used. The priming process includes applying the primer to the outer surface of the base layer (the surface that adheres to the elastic layer) and then drying or firing it.

[0047] In this example, taking into consideration the above materials, a polyimide resin base with VGFC-H (manufactured by Showa Denko K.K.) added as a filler was used as the base layer 301a. The filler was added in a volume fraction range of 0.5 to 30 vol.

[0048] When considering the sliding effect of the belt 301 on the sliding member 304, it is necessary to consider the roughness and hardness of the contact surfaces of these members, as well as the viscosity of the lubricant (release layer) provided between them. These parameters should be measured in advance and added to the conditions of the examples described below as parameters to be considered during evaluation. The measurement methods for these parameters will be explained below.

[0049] (Method for measuring internal surface roughness) The inner surface roughness of the base layer 301a was measured by cutting open the belt 301 and measuring it in the circumferential direction under the following conditions. Equipment: Surface roughness measuring instrument SE3000 (manufactured by Kosaka Seisakusho) Measurement conditions; compliant with JIS B 0601:1994 Measurement length = 4mm, cutoff value = 0.8mm, feed rate: 0.1mm / s Filter: Gaussian filter (λs:λc / 30) The evaluation was performed using the arithmetic mean roughness Ra.

[0050] (Method for measuring hardness) The Martens hardness of the contact surface of the friction member 304 with the belt 301, and the inner circumferential surface of the belt 301 were measured under the following conditions. Device: PICODENTOR HM500 (manufactured by Fischer Instruments) Measurement conditions: Test load = 20 mN, maximum indentation depth = 2500 nm Load application time = 1 s, creep time = 5 s As a result, the hardness of the inner surface of belt 301 is 370 N / mm². 2 The hardness of the surface of the coating layer 304b, which is placed between the belt 301 and the friction member 304, is 60 N / mm². 2 That was the case.

[0051] (Method for measuring lubricant viscosity) The viscosity of the lubricant formed as the release layer 301c was measured under the following conditions. Equipment: AR-G2 rheometer (manufactured by TA Instruments) Conditions: Measured at 200°C in accordance with ASTM D445 standard.

[0052] (Method for controlling the roughness of the base layer surface) In this embodiment and the embodiments described below, the filler addition rate to the PI varnish added to the raw materials was changed in order to control the roughness of the inner surface of the base layer 301a. Specifically, as the raw material for the PI base layer, VGFC-H (manufactured by Showa Denko K.K.) was added as a filler to Yupia U-Varnish S (manufactured by Ube Industries, Ltd.) so that the final volume fraction was 0.5 to 30 vol%. After mixing using a rotary-orbit mixer, belt 301 was produced by rotary centrifugal molding.

[0053] In this example, a belt 301 was used with a base layer 301a to which 0.5 vol% of filler was added so that the inner surface roughness was 0.03 μm. The viscosity of the lubricant used was 0.01 Pas, and the roughness of the inner surface of the belt 301 and the friction member 304 was set so that the sum of the roughness of the inner surface of the base layer 301a and the friction member 304 was 0.06 μm. Then, the above-mentioned evaluations were performed using the heating and fixing apparatus shown in Figure 2, which was obtained by setting the Martens hardness of the friction member 304 to be less than the Martens hardness of the inner surface of the belt 301 (base layer 301a). The obtained evaluation results are shown in Table 1. As shown in Table 1, with the fixing apparatus according to Example 1, an A rating was obtained for coat wear, oil depletion, and fixing performance.

[0054] <Example 2> In Example 2, a belt 301 was used with a base layer 301a to which 15 vol% of filler was added so that the inner surface roughness was 0.19 μm. The lubricant viscosity was set to 10 Pas, and the roughness of the inner surface of the belt 301 (base layer 301a) and the surface of the sliding member 304 were set so that the sum of these roughnesses was 0.22 μm. For all other conditions, the heat fixing apparatus obtained in the same manner as in Example 1 was evaluated. With the heat fixing apparatus of Example 2, an A rating was obtained for coat wear, oil depletion, and fixing performance.

[0055] <Example 3> In Example 3, the combination of the friction member 304 and the belt 301 was such that the sum of the roughness of the inner circumferential surface of the belt 301 (base layer 301a) and the surface of the friction member 304 was 0.60 μm. The lubricant viscosity was set to 10 Pas. For all other conditions, the same heating and fixing apparatus as in Example 1 was evaluated. With the heating and fixing apparatus of Example 3, an A rating was obtained for coat wear, oil depletion, and fixing performance.

[0056] <Example 4> In Example 4, a belt 301 was used that had a base layer 301a with 15 vol% filler added to achieve an internal surface roughness of 0.19 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 3. The heating and fixing apparatus in Example 4 received an A rating for coat wear, oil depletion, and fixing performance.

[0057] <Example 5> In Example 5, a fixing belt was used with a base layer 301a to which 20 vol% of filler was added so that the inner surface roughness of the base layer was 0.30 μm. The roughness of the inner circumferential surface of belt 301 (base layer 301a) and the surface of the friction member 304 were set so that the sum of these roughnesses was 0.33 μm. The heating fixing apparatus was evaluated under the same conditions as in Example 3. With the heating fixing apparatus of Example 5, an A rating was obtained for both oil depletion and fixing performance, but a B rating was obtained for coat wear.

[0058] <Example 6> In Example 6, the lubricant viscosity was set to 0.001 Pas. The heating and fixing apparatus was evaluated under the same conditions as in Example 1. With the heating and fixing apparatus of Example 6, an A rating was obtained for both coat wear and fixing performance, but a B rating was obtained for oil depletion.

[0059] <Example 7> In Example 7, the lubricant viscosity was set to 15.0 Pas. The roughness of the inner circumferential surface of the belt 301 (base layer 301a) and the surface of the sliding member 304 were set so that the sum of these roughnesses was 0.33 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 1. With the heating and fixing apparatus of Example 7, an A rating was obtained for both oil depletion and fixing performance, but a B rating was obtained for coat wear.

[0060] <Example 8> In Example 8, a fixing belt was used with a base layer 301a to which 20 vol% of filler was added so that the inner surface roughness of the base layer was 0.30 μm. Furthermore, the roughness of the inner circumferential surface of belt 301 (base layer 301a) and the surface of the abrasive member 304 were such that the sum of these roughnesses was 0.61 μm. The heating fixing apparatus was evaluated under the same conditions as in Example 5. With the heating fixing apparatus of Example 8, an A rating was obtained for oil depletion, but a B rating was obtained for coat wear and fixing performance.

[0061] <Example 9> In Example 9, the lubricant viscosity was set to 0.001 Pas. The roughness of the inner surface of the belt 301 (base layer 301a) and the surface of the sliding member 304 were set so that the sum of these roughnesses was 0.05 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 1. With the heating and fixing apparatus of Example 9, an A rating was obtained for both coat wear and fixing performance, but a B rating was obtained for oil depletion.

[0062] <Example 10> In Example 10, the lubricant viscosity was set to 0.001 Pas. The roughness of the inner circumferential surface of the belt 301 (base layer 301a) and the surface of the sliding member 304 were set so that their sum was 0.61 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 1. With the heating and fixing apparatus of Example 10, an A rating was obtained for coat wear, but a B rating was obtained for both oil depletion and fixing performance.

[0063] <Example 11> In Example 11, the roughness of the inner circumferential surface of the belt 301 (base layer 301a) and the surface of the abrasive member 304 were set so that their sum was 0.33 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 6. With the heating and fixing apparatus of Example 11, an A rating was obtained for both oil depletion and fixing performance, but a C rating was obtained for coat wear.

[0064] <Example 12> In Example 12, the filler amount was set to 0.4 vol% and the lubricant viscosity to 10 Pas. For all other conditions, the heating and fixing apparatus was evaluated in the same manner as in Example 1. With the heating and fixing apparatus of Example 12, an A rating was obtained for both coat wear and fixing performance, but a B rating was obtained for oil depletion.

[0065] <Example 13> In Example 13, the inner surface roughness of belt 301 (base layer 301a) was set to 0.3 μm, and the filler amount was set to 21 vol%. For all other conditions, the same heating and fixing apparatus as in Example 5 was evaluated. With the heating and fixing apparatus of Example 13, an A rating was obtained for both oil depletion and fixing performance, but a B rating was obtained for coat wear.

[0066] <Comparative Example 1> In Comparative Example 1, no lubricant was applied. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. The heating and fixing apparatus in Comparative Example 1 received a D rating for coat wear and oil depletion, and an A rating for fixing performance.

[0067] <Comparative Example 2> In Comparative Example 2, the inner surface roughness of belt 301 (base layer 301a) was set to 0.2 μm, and the filler amount was set to 0.4 vol%. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 2, an A rating was obtained for both coat wear and fixing performance, but a D rating was obtained for oil depletion.

[0068] <Comparative Example 3> In Comparative Example 3, the Martens hardness of the abrasive member 304 was set to be greater than or equal to the Martens hardness of the inner circumferential surface of the belt 301 (base layer 301a). The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 3, an A rating was obtained for both oil depletion and fixing performance, but a D rating was obtained for coat wear.

[0069] <Comparative Example 4> In Comparative Example 4, the inner surface roughness of belt 301 (base layer 301a) was set to 0.31 μm, and the filler amount was set to 22 vol%. The roughness of the inner surface of belt 301 (base layer 301a) and the surface of the friction member 304 were set so that the sum of these roughnesses was 0.34 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 4, an A rating was obtained for both oil depletion and fixing performance, but a D rating was obtained for coat wear.

[0070] <Comparative Example 5> In Comparative Example 5, the sum of the roughness of the inner circumferential surface of the belt 301 (base layer 301a) and the surface of the sliding member 304 was set to 0.05 μm, the filler amount was set to 22 vol%, and the lubricant viscosity was set to 10 Psa. The heating and fixing apparatus was evaluated under the same conditions as in Example 1. With the heating and fixing apparatus of Comparative Example 5, an A rating was obtained for both coat wear and fixing performance, but a D rating was obtained for oil depletion.

[0071] <Comparative Example 6> In Comparative Example 6, the inner surface roughness of belt 301 (base layer 301a) was set to 0.02 μm, and the filler amount was set to 0.4 vol%. The roughness of the inner surface of belt 301 (base layer 301a) and the surface of the friction member 304 were set so that the sum of these roughnesses was 0.22 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 6, an A rating was obtained for both coat wear and fixing performance, but a D rating was obtained for oil depletion.

[0072] <Comparative Example 7> In Comparative Example 7, the inner surface roughness of belt 301 (base layer 301a) was set to 0.02 μm, and the filler amount was set to 15 vol%. The roughness of the inner surface of belt 301 (base layer 301a) and the surface of the friction member 304 were set so that the sum of these roughnesses was 0.22 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 7, an A rating was obtained for both coat wear and fixing performance, but a D rating was obtained for oil depletion.

[0073] <Comparative Example 8> In Comparative Example 8, the inner surface roughness of belt 301 (base layer 301a) was set to 0.31 μm, and the filler amount was set to 20 vol%. Furthermore, the sum of the roughness of the inner surface of belt 301 (base layer 301a) and the surface of the friction member 304 was set to 0.34 μm. The heating and fixing apparatus was evaluated under the same conditions as in Example 2. With the heating and fixing apparatus of Comparative Example 4, an A rating was obtained for both fixing performance and oil depletion, but a D rating was obtained for coat wear.

[0074] The results of these evaluations are summarized in the table below. [Table 1]

[0075] It was previously known that roughening the inner surface of the belt 301 improves the retention of lubricant. However, this embodiment confirmed that if the roughness is increased too much to retain the lubricant, the surface layer of the opposing component is scraped away, significantly reducing its lifespan. Therefore, by setting the above conditions within the range shown in the present invention, referring to the results of the examples and comparative examples, it was possible to improve the durability of the fuser while simultaneously achieving suitable image fixing.

[0076] As described above, the fixing device according to one aspect of the present invention includes an endless belt, a rotating body, a rubbing member, a pressing member, and a heating member (heat source). The belt 301 that functions as an example of the endless belt has a surface layer (release layer 301c) that is an outer surface layer and a base material (base layer 301a). The pressure roller 305 that functions as an example of the rotating body contacts the release layer 301c of the belt 301. The rubbing member 304 exemplified in the embodiments contacts the base layer 301a located on the inner peripheral surface of the belt 301. The pressing member 303 exemplified in the embodiments presses the belt 301 toward the pressure roller 305 that is the rotating body via the rubbing member 304. Also, between the rubbing member 304 and the belt 301, there is a lubricant exemplified as silicone oil in the examples. With the above configuration, the arithmetic mean roughness of the inner peripheral surface of the belt 301 is set to be 0.03 μm or more and 0.30 μm or less. When the arithmetic mean roughness is greater than 0.30 μm, there is a risk of promoting wear of the inner peripheral surface of the belt 301. Also, the Martens hardness H1 of the rubbing member 304 and the Martens hardness H2 of the inner peripheral surface of the belt 301 satisfy H1 < H2. By satisfying such conditions, in the fixing device according to the present invention, in an image forming apparatus, it is possible to maintain the life of the fixing belt for a long time while holding the lubricant and without shaving the coat layer of the rubbing member. In the fixing device according to the present invention, in an image forming apparatus, it is possible to maintain the life of the fixing belt for a long time while holding the lubricant and without shaving the coat layer of the rubbing member.

[0077] In the fixing device described above, it is preferable that the base layer 301a of the belt 301 contains 0.5 volume % or more and 20 volume % or less of a filler. Also, it is preferable that the arithmetic mean roughness of the inner peripheral surface of the belt 301 is 0.03 μm or more and 0.19 μm or less. Also, it is preferable that the lubricant has a viscosity at 200°C of 0.01 Pas or more and 10 Pas or less. Further, it is preferable that the sum of the arithmetic mean roughness of the inner peripheral surface of the belt 301 and the arithmetic mean roughness of the rubbing member 304 is 0.06 μm or more and 0.60 μm or less. When the sum of the arithmetic mean roughness is less than 0.06 μm, the retention of the lubricant deteriorates.

[0078] The present invention includes the following configurations. (Configuration 1) An endless belt having a surface layer that is an outer surface layer and a base material having an inner peripheral surface, A rotating body that contacts the surface layer of the endless belt, A rubbing member that contacts the inner peripheral surface of the endless belt, A pressing member that presses the endless belt toward the rotating body through the rubbing member, and A fixing device having a heating source for heating the endless belt, wherein A lubricant exists between the rubbing member and the endless belt, The arithmetic mean roughness of the inner peripheral surface of the endless belt is 0.03 μm or more and 0.30 μm or less, The martensite hardness H1 of the rubbing member and the martensite hardness H2 of the inner peripheral surface of the endless belt satisfy H1 < H2, and the fixing device is characterized by this. (Configuration 2) The base material of the endless belt contains 0.5% by volume or more and 20% by volume or less of a filler, and the fixing device according to Configuration 1. (Configuration 3) The arithmetic mean roughness of the inner peripheral surface of the endless belt is 0.03 μm or more and 0.19 μm or less, and the fixing device according to Configuration 1 or 2. (Configuration 4) The lubricant has a viscosity at 200 °C of 0.01 Pas or more and 10 Pas or less, and the fixing device according to Configuration 1 or 2. (Configuration 5) The sum of the arithmetic mean roughness of the inner peripheral surface of the endless belt and the arithmetic mean roughness of the rubbing member is 0.06 μm or more and 0.60 μm or less, and the fixing device according to Configuration 1 or 2 is characterized by this. (Configuration 6) A toner image forming unit that forms a toner image on a photosensitive drum, A transfer unit that transfers the toner image on the photosensitive drum, A fixing device that fixes the transferred toner image to a recording medium, and is provided with The fixing device is An endless belt having a surface layer that is an outer surface layer and a base material having an inner peripheral surface, A rotating body that contacts the surface layer of the endless belt, A rubbing member that contacts the inner peripheral surface of the endless belt, A pressing member that presses the endless belt toward the rotating body via the rubbing member, and A heating source that heats the endless belt, and has There is a lubricant between the rubbing member and the endless belt, The arithmetic mean roughness of the inner peripheral surface of the endless belt is 0.03 μm or more and 0.30 μm or less, The martensite hardness H1 of the rubbing member and the martensite hardness H2 of the inner peripheral surface of the endless belt satisfy H1 < H2, and an image forming apparatus characterized by this.

[0079] As described above, the present disclosure has been described with reference to the embodiments and modified examples. However, the present disclosure is not limited to the above embodiments and modified examples. Inventions modified within the scope not contrary to the gist of the present disclosure, and inventions equivalent to the present disclosure are also included in the present disclosure. In addition, the above-described embodiments and modified examples can be appropriately combined within the scope not contrary to the gist of the present disclosure.

Explanation of Signs

[0080] F... Fixing device N... nip portion 301... Fixing belt (belt) 302... Stay 303... Pressing and pressing member (pressing member) 304... Rubbing member 305... Pressing roller 306... Halogen heater 307... Heating roller

Claims

1. An endless belt having a surface layer which is an outer layer and a base material which has an inner circumferential surface, A rotating body that comes into contact with the surface of the endless belt, A friction member that contacts the inner circumferential surface of the endless belt, A pressing member that presses the endless belt toward the rotating body via the sliding member, and A fixing device having a heating source for heating the endless belt, A lubricant is present between the sliding member and the endless belt. The arithmetic mean roughness of the inner surface of the endless belt is 0.03 μm or more and 0.30 μm or less. A fixing device characterized in that the Martens hardness H1 of the abrasive member and the Martens hardness H2 of the inner circumferential surface of the endless belt satisfy H1 < H2.

2. The fixing device according to claim 1, wherein the base material of the endless belt contains 0.5% by volume or more and 20% by volume or less of a filler.

3. The fixing device according to claim 1 or 2, wherein the arithmetic mean roughness of the inner surface of the endless belt is 0.03 μm or more and 0.19 μm or less.

4. The fixing device according to claim 1 or 2, wherein the lubricant has a viscosity of 0.01 Pas or more and 10 Pas or less at 200°C.

5. The fixing device according to claim 1 or 2, characterized in that the sum of the arithmetic mean roughness of the inner surface of the endless belt and the arithmetic mean roughness of the abrasive member is 0.06 μm or more and 0.60 μm or less.

6. A toner image forming unit that forms a toner image on a photosensitive drum, A transfer unit that transfers the toner image on the photosensitive drum, The system includes a fixing device for fixing the transferred toner image onto a recording medium, The fixing device is An endless belt having a surface layer which is an outer layer and a base material which has an inner circumferential surface, A rotating body that comes into contact with the surface of the endless belt, A friction member that contacts the inner circumferential surface of the endless belt, A pressing member that presses the endless belt toward the rotating body via the sliding member, and The endless belt has a heating source, A lubricant is present between the sliding member and the endless belt. The arithmetic mean roughness of the inner surface of the endless belt is 0.03 μm or more and 0.30 μm or less. An image forming apparatus characterized in that the Martens hardness H1 of the abrasive member and the Martens hardness H2 of the inner circumferential surface of the endless belt satisfy H1 < H2.

Images