Fixing member, fixing device, and electrophotographic image forming apparatus

Abstract

To provide a fixing member that has an elastic layer with insulating properties including an area containing an ion conductive agent, and thereby can reduce an absolute value of a charged electric potential, increase charge attenuation properties when left standing, and prevent electrostatic offset.SOLUTION: A fixing member has a base layer, an elastic layer on the base layer, and a layer structure on a surface of the elastic layer on the opposite side of a side facing the base layer. The layer structure includes at least a surface layer forming an outer surface of the fixing member. A thickness of the layer structure is 100 μm or less. Surface resistivity on a surface of the layer structure on the opposite side of a side facing the base layer is 1×1015 Ω / sq. or more. A thickness of the elastic layer is 100 μm or more. Surface resistivity on a first surface of the elastic layer on a side facing the layer structure is 1×1014 Ω / sq. or more. A first area from the first surface of the elastic layer to a position at a depth of 10 μm includes an ion conductive agent in an amount of 5.0 mass% or more with respect to mass of the first area.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a fixing member used in a fixing device of an electrophotographic image forming apparatus, a fixing device, and an electrophotographic image forming apparatus. [Background technology]

[0002] Fixing members used in the fixing devices of electrophotographic image forming apparatuses such as printers, copiers, and facsimiles are available in the form of films or rollers. These fixing members include a fixing member having a heat-resistant resin or metal film or roller-shaped base material made of heat-resistant resin or metal, an elastic layer on the base material, and a release layer on the elastic layer. Here, the release layer often contains a fluororesin that has excellent releasability against toner.

[0003] Fluorine resin is most likely to be negatively charged in the triboelectric series, and therefore, when the surface of the fixing member, i.e., the outer surface of the release layer, rubs against paper or a pressure member during the process of forming an electrophotographic image, the release layer of the fixing member becomes charged, and electrostatic offset occurs in which unfixed toner electrostatically adheres to the release layer of the fixing member.

[0004] Patent Document 1 discloses a fixing device having a fixing member whose surface material that comes into contact with a toner image contains at least a fluororesin and an ion-conductive electrical resistance control material having a melting point equal to or higher than the maximum operating temperature of the fixing device, and describes that this fixing device can prevent the occurrence of electrostatic offset. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 08-220907 Summary of the Invention [Problem to be solved by the invention]

[0006] At least one aspect of the present disclosure is directed to providing a fixing member capable of stably exerting an effect of preventing electrostatic offset. At least one aspect of the present disclosure is directed to providing a fixing device that contributes to the stable formation of high-quality electrophotographic images. Furthermore, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus capable of forming high-quality electrophotographic images. [Means for solving the problem]

[0007] According to at least one aspect of the present disclosure, there is provided a fixing member having a base layer, an elastic layer on the base layer, and a layer structure on a surface of the elastic layer opposite to a surface facing the base layer, the layer structure comprising: The layer structure includes at least a surface layer that constitutes an outer surface of the fixing member, The thickness of the layer structure is 100 μm or less, The surface resistivity of the layer structure measured on the surface opposite to the side facing the base layer is 1×10 15 Ω / □ or more, The thickness of the elastic layer is 100 μm or more, The surface resistivity of the elastic layer measured on a first surface facing the layer structure is 1×10 14 Ω / □ or more, The fixing member includes a first region of the elastic layer from the first surface to a position at a depth of 10 μm, the first region containing an ion conductive agent in an amount of 5.0% by mass or more based on the mass of the elastic layer.

[0008] Furthermore, according to at least one aspect of the present disclosure, there is provided a fixing device including a fixing member, a pressure member that applies pressure to the outer peripheral surface of the fixing member to form a nip portion with the fixing member, and a heating member that heats the fixing member, wherein the fixing member is the fixing member described above. Furthermore, according to at least one aspect of the present disclosure, there is provided an electrophotographic image forming apparatus including the above fixing device. Effect of the Invention

[0009] According to at least one aspect of the present disclosure, a fixing member capable of stably exhibiting the effect of preventing electrostatic offset can be obtained. Also, according to at least one aspect of the present disclosure, a fixing device contributing to the stable formation of high-quality electrophotographic images can be obtained. Furthermore, according to at least one aspect of the present disclosure, an electrophotographic image forming apparatus capable of forming high-quality electrophotographic images can be obtained. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic diagram of a fixing device according to an embodiment of the present disclosure. [Diagram 3] 1 is a schematic cross-sectional view of a fuser member according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram illustrating a first region and a second region in an elastic layer of a fixing member according to an embodiment of the present disclosure. [Diagram 5] 6A and 6B are explanatory diagrams of a presumed mechanism by which the fixing member according to the embodiment of the present disclosure exerts an effect of preventing electrostatic offset. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the present disclosure, the description of a numerical range such as "XX or more and YY or less" or "XX to YY" means a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0012] When the present inventors studied the fixing member according to Patent Document 1, they found that the effect of preventing electrostatic offset gradually decreased. It was believed that the change over time in the effect of preventing electrostatic offset of the fixing member according to Patent Document 1 was due to the ion conductive agent in the surface layer of the fixing member bleeding to the surface. Therefore, the present inventors conducted extensive studies to obtain a fixing member that can stably prevent electrostatic offset over a long period of time. As a result, they found that a fixing member having the following configuration can stably prevent electrostatic offset over a long period of time.

[0013] <Configuration> The fixing member includes a base layer, an elastic layer on the base layer, and a layer structure on the surface of the elastic layer opposite to the side facing the base layer. The layer structure includes at least a surface layer that constitutes the outer surface of the fixing member, the layer structure has a thickness of 100 μm or less, and the surface resistivity of the layer structure measured on the surface opposite to the side facing the base layer is 1×10 15 The elastic layer has a thickness of 100 μm or more, and the surface resistivity measured on a first surface of the elastic layer facing the layer structure is 1×10 14 The surface resistance is Ω / □ or more. Furthermore, a first region of the elastic layer from the first surface to a position at a depth of 10 μm contains an ion conductive agent in an amount of 5.0% by mass or more based on the mass of the elastic layer.

[0014] A fixing member and an image forming apparatus according to one embodiment of the present disclosure will be described with reference to the drawings, but the fixing member according to the present disclosure is not limited to the configuration embodied in this embodiment.

[0015] <Fixing material> The fixing member according to one embodiment of the present disclosure may be, for example, a rotating body for fixing. Non-limiting examples of the rotating body for fixing include, for example, a fixing roller and a fixing belt having an endless shape. Hereinafter, the fixing member will be described using an example of a fixing belt having an endless shape (hereinafter, sometimes simply referred to as a "fixing belt"). As shown in Fig. 3, the fixing belt according to this embodiment has at least a laminated structure of a base layer 41d having an endless shape, an elastic layer 41c on the base layer, and a layer structure 41f provided on the surface of the elastic layer opposite to the side facing the base layer. The layer structure 41f has at least a surface layer 41a forming the outer surface of the fixing member on the surface opposite to the surface facing the elastic layer. An adhesive layer 41b made of resin may be provided on the surface of the elastic layer 41c opposite to the side facing the base layer, thereby further improving the adhesion between the surface layer 41a and the elastic layer 41c.

[0016] The reason why the fixing member according to this embodiment can suppress electrostatic offset despite having a laminated structure of a high-resistance layer structure 41f and a high-resistance elastic layer 41c is presumed to be as follows. As shown in FIG. 5, in the fixing process of an electrophotographic image, when the outer surface of the surface layer 41a is rubbed by the movement of the recording material 500 in the direction of the arrow 501, the vicinity of the outer surface 41S of the surface layer is negatively charged, and the surface side opposite to the outer surface 41S of the surface layer is positively charged. Then, in response to the polarization in the thickness direction of the surface layer 41f, the anions of the ion conductive agent in the first region 41g of the elastic layer 41c move to the side closer to the surface layer 41f, and the cations move to the side closer to the second region 41h of the first region 41g. As a result, the negative charge generated on the outer surface side of the surface layer 41f is alleviated by the cations closer to the second region 41h of the first region 41g of the elastic layer 41c, and the charge is neutralized in the entire fixing member.

[0017] The correctness of this mechanism is considered to be evident from the results of the following experiment. The present inventors prepared the following electrophotographic belt. It had a laminated structure of a base layer, an elastic layer on the base layer, an insulating adhesive layer, and a surface layer (thickness 9 μm) as a layer structure, and the surface resistivity of the elastic layer was set to 1×10 14 Ω / □, and the surface resistivity of the surface layer is 1×10 15The elastic layer was measured to have a resistance of Ω / □. Prior to the adhesion of the surface layer, the outer surface of the elastic layer, which is the surface to be adhered of the surface layer of the elastic layer containing silicone rubber, was irradiated with ultraviolet light, and then the ultraviolet irradiated surface was coated with an ion conductive agent and left for 30 seconds. Then, the ion conductive agent was impregnated into a thickness region of 10 μm deep from the outer surface of the elastic layer. Then, an electrically insulating surface layer was provided on the outer surface of the elastic layer via an electrically insulating adhesive layer. After the outer surface 41S of the electrophotographic belt thus obtained was neutralized, the grid part of the corona discharger was placed with a gap of 10 mm from the outer surface, and a voltage of -5 kV was applied to the corona discharger for 15 seconds. The potential of the outer surface was measured at 0.1 second intervals, starting from the point (0 seconds) when the voltage application to the corona discharger was stopped. As a result, the highest potential was -620 V 10 seconds after the discharge was stopped. On the other hand, when the same measurement was performed on an electrophotographic belt as a control example in which the elastic layer was not impregnated with an ion conductive agent, the highest surface potential of the surface layer was −750 V. That is, although the surface layer and the elastic layer were insulating, the outer surface of the electrophotographic belt according to one embodiment of the present disclosure was difficult to be charged. From this, it is considered that the effect of the fixing member according to the present disclosure is not obtained by discharging the charge of the surface layer to the base layer side, but by charge neutralization (charge relaxation).

[0018] (1) Base layer The material of the base layer is not particularly limited, and may be any known material used as a base layer of a fixing belt. Examples include metals and alloys such as aluminum, iron, stainless steel, and nickel, and heat-resistant resins such as polyimide. The thickness is not particularly limited, but is preferably 20 μm or more and 100 μm or less from the viewpoints of strength, flexibility, and heat capacity. Since the base layer has an endless shape, it has an inner surface on the inside of the endless shape and an outer surface on the outside. The outer surface of the base layer may be subjected to a surface treatment to improve adhesion to the elastic layer. The surface treatment may be one or a combination of physical treatments such as blasting, lapping, and polishing, and chemical treatments such as oxidation, coupling agent, and primer treatment.

[0019] When an elastic layer containing silicone rubber is provided on the outer surface of the base layer, the outer surface of the base layer can be subjected to a primer treatment in order to further improve the adhesion between the base layer and the elastic layer. Examples of the primer used for the primer treatment include paints in which a silane coupling agent, a silicone polymer, hydrogenated methylsiloxane, an alkoxysilane, a reaction-accelerating catalyst, and a colorant such as red iron oxide are appropriately mixed and dispersed in an organic solvent. The primer can be appropriately selected depending on the material of the base layer, the type of the elastic layer, or the form of the crosslinking reaction. In particular, when a material containing a large number of unsaturated aliphatic groups is used for the elastic layer, a primer containing a hydrosilyl group that can impart adhesion by reacting with the unsaturated aliphatic group is preferably used. Conversely, when a material containing a large number of hydrosilyl groups is used for the elastic layer, a primer containing an unsaturated aliphatic group is preferably used. Other examples of primers include those containing alkoxy groups. Commercially available primers can be used. The primer treatment includes a step of applying the primer to the outer surface of the base layer (the surface to be bonded to the elastic layer) and drying or baking the primer. When the fixing member is in the form of a fixing roller, the base layer has a hollow cylindrical or solid cylindrical shape, and when it is made of a metal material or the like, it is sometimes called a core bar.

[0020] (2) Elastic layer In order to achieve a better charge neutralization effect by the layer structure described below, the elastic layer 41c has a first region 41g as shown in Fig. 4. The first region 41g is a region from a first surface 41c-S1 of the elastic layer 41c facing the layer structure 41f to a position 10 µm thick toward a second surface 41c-S2 of the elastic layer 41c. The surface resistivity of the first surface 41c-S1 of the elastic layer 41c is 1 x 10 14Ω / □ or more. The first region 41g contains an ion conductive agent. The content of the ion conductive agent in the first region 41g is 5.0 mass% or more based on the mass of the elastic layer 41c (including the mass of the ion conductive agent, the same applies below). The upper limit of the amount of the ion conductive agent in the first region 41g is not particularly limited as long as the surface resistivity of the first surface 41c-S1 is 1×1014 Ω / □ or more. However, from the viewpoint of better maintaining the elasticity of the elastic layer, it is preferably 10.0 mass% or less based on the mass of the elastic layer 41c. The content of the ion conductive agent in the first region 41g is preferably 5.0 to 10.0 mass% based on the mass of the elastic layer 41c. The region of the elastic layer 41c from a position 10 μm deep from the first surface 41c-S1 to the second surface 41c-S2 is defined as the second region 41h. In order to better exert the effect of the charge neutralization, it is preferable that the second region 41h contains as little conductive agent as possible, and it is particularly preferable that the second region 41h does not contain any conductive agent at all. Therefore, the content of the conductive agent in the second region 41h is preferably 0.5 mass% or less, and particularly preferably 0 mass% or more and 0.5 mass% or less, based on the mass of the elastic layer 41c.

[0021] In addition, the fixing member according to the present disclosure preferably has a surface potential of -700 V or more (approaching 0 V), particularly -650 V or more, and further preferably -600 V or more, when the surface potential reaches its highest value after the discharge is stopped, as measured by applying a voltage with a corona discharger as described above. This makes it possible to more effectively prevent electrostatic offset.

[0022] The material of the elastic layer is not particularly limited, and a known material used as an elastic layer of a fixing belt can be adopted. For example, it is preferable that the elastic layer contains silicone rubber having excellent heat resistance. In addition, addition curing type liquid silicone rubber is preferably used as a raw material of the silicone rubber. An ionic conductive agent can be added to the silicone rubber for forming the elastic layer. The ionic conductive agent to be added will be described later. The thickness of the elastic layer can be designed appropriately in consideration of the surface hardness of the fixing member and the width of the fixing nip portion to be formed, but in this disclosure, it is 100 μm or more. The upper limit of the thickness of the elastic layer is not particularly limited, but it is generally designed to be in the range of 3000 μm or less. By making the thickness of the elastic layer 100 μm or more, a sufficient width of the fixing nip portion can be secured when the fixing rotor is incorporated into the fixing device. If the thickness of the elastic layer is less than 100 μm, the surface deformation of the fixing member becomes small, and the following ability of the fixing member to the recording material is insufficient. This makes it possible to suppress a situation in which the heat conduction from the fixing member to the recording material is insufficient.

[0023] The elastic layer may contain a filler to the extent that the effect of the present disclosure is not impaired. The filler is added to control thermal conductivity, heat resistance, and elastic modulus. Specifically, these include non-conductive fillers such as silicon carbide (SiC), silicon nitride (Si3N4), silica (SiO2), boron nitride (BN), aluminum nitride (AlN), alumina (Al2O3), iron oxide (Fe2O3), zinc oxide (ZnO), magnesium oxide (MgO), and titanium oxide (TiO2). As described above, the elastic layer may contain a thermally conductive filler or an electrically conductive filler in order to improve thermal conductivity in the thickness direction, but the amount added is within a range that does not fall below this surface resistance value.

[0024] The material constituting the elastic layer may contain a reaction control agent (blocking agent) called an inhibitor to control the reaction start time. Known substances such as methylvinyltetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxides are used as reaction control agents.

[0025] (Ionic Conductive Agent) The ionic conductive agent is not particularly limited, but is preferably, for example, an ionic liquid. Here, the ionic liquid refers to a salt consisting of a cation and an anion and having a melting point of 100° C. or less. Examples of the ionic liquid include ionic liquids formed from combinations of cations exemplified below. Cations: ammonium-based cations, imidazolium-based cations, pyridinium-based cations, piperidinium-based cations, pyrrolidinium-based cations, phosphonium-based cations. Anion: ClO4 - , Br - , Cl - , AlCl4 - , Al2Cl7 - , NO3 - , BF4 - , PF6 - , CH3COO - , CF3COO - , CF3SO3 - , (CF3SO2)3C - , AsF6 - , SbF6 - , F(HF) n - , CH3CH2OSO3 - , H2PO4 - , CF3CF2CF2CF2SO3 - , CF3CF2CF2COO - , N - (SO2CF3)2. Among these, it is particularly preferable to use an ionic liquid having a chemical structure represented by the following formula (1): This ionic liquid is available, for example, under the name "FC-4400" (product name, manufactured by 3M Japan). (n-C4H9)3(CH3)N + N - (SO2CF3)2(1)

[0026] (3) Layered structure The layer structure 41f can include, for example, a surface layer 41a that constitutes the outer surface of the fixing member, and an adhesive layer 41b for adhering the surface layer 41a onto the elastic layer. The surface resistivity measured on the surface of the layer structure 41f opposite to the side facing the base layer, i.e., the surface of the surface layer 41a opposite to the side facing the adhesive layer 41b, is 1×10 15 It is Ω / □ or more. The surface layer preferably contains a fluororesin so as to better suppress adhesion of the toner to the outer surface of the fixing member. Examples of the fluororesin include tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), perfluoropolyether (PFPE), polytetrafluoroethylene (PTFE), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). Among them, PFA, which has excellent heat resistance and toner releasability, is particularly preferably used. The thickness of the surface layer is preferably 100 μm or less, and particularly preferably 10 to 70 μm. By setting the thickness within this range, when polarization occurs in the surface layer, a polarized state of the ion conductive agent corresponding to the polarization can be more reliably generated in the first region of the elastic layer (see FIG. 5). A tube can be used for the surface layer, and when a tube is used for the surface layer, it is preferable to subject the inner surface of the tube to sodium treatment, excimer laser treatment, ammonia treatment, or plasma etching treatment in advance. This is because the adhesiveness to the elastic layer and adhesive layer can be improved. In this embodiment, a PFA tube with a thickness of 20 μm obtained by extrusion molding is used. The inner surface of the tube is subjected to plasma etching treatment to improve wettability with the adhesive described later. The layer structure has an outer surface resistivity of 1×10 15 Provided that the resistance is Ω / □ or more, carbon black and the like may be contained.

[0027] The adhesive layer is a layer that is optionally provided to improve adhesion with the surface layer. 15 Any material may be used as long as it satisfies Ω / □ or more and can be used to manufacture a fixing belt. Also, depending on the circumstances, the adhesive layer 41b may be a multi-layer or may be omitted. In this embodiment, the adhesive layer can be an addition curing type silicone rubber adhesive. These have an uncrosslinked silicone rubber component, and when heated, the inner surface treatment layer of the surface layer and the uncrosslinked component of the elastic layer bond to each other, thereby bonding the surface layer and the elastic layer. Here, it is preferable that the adhesive layer does not have electrical conductivity that allows the transfer of electric charges between the elastic layer and the surface layer, in order to better realize the charge neutralization effect of the surface layer.

[0028] (Method of Manufacturing Fixing Member) <Process for preparing the substrate> A substrate is prepared. When the substrate has an endless shape, it is preferable to insert a core or the like to suppress deformation of the substrate during the manufacturing process. If necessary, the substrate is subjected to a surface treatment such as coating a primer on the surface (outer peripheral surface) on which the elastic layer is to be formed.

[0029] <Step of forming elastic layer> An elastic layer is formed on the outer peripheral surface of the substrate. The method of forming the elastic layer on the outer peripheral surface of the substrate is not particularly limited, and a conventionally known method can be used. For example, a method of applying an addition curing type silicone rubber composition, which is the material of the elastic layer, to the outer surface of the substrate using a ring coat method and curing by heating can be mentioned. For example, an addition curing type silicone rubber composition can be mentioned as the material of the elastic layer.

[0030] <Surface treatment process for elastic layer> The surface of the elastic layer opposite to the side facing the base material is irradiated with ultraviolet light. As an irradiation method, it is preferable to irradiate the entire outer surface of the elastic layer with ultraviolet light uniformly. For example, while rotating the belt material at a constant moving speed in the circumferential direction, irradiation is performed in an atmospheric environment using an ultraviolet lamp arranged at a constant distance from the surface of the elastic layer. This process of irradiating the surface of the elastic layer with ultraviolet light is a process for adjusting the amount of penetration of the ion conductive agent into the elastic layer in the impregnation process of the ion conductive agent performed subsequent to this process. The ultraviolet light irradiation can promote crosslinking of the uncrosslinked silicone rubber component near the surface of the elastic layer. As a result, the crosslinked structure of the silicone rubber on the surface of the elastic layer develops and becomes dense, so that the penetration speed of the ion conductive agent from the surface can be adjusted (decreased) and the content of the ion conductive agent can be adjusted.

[0031] <Ion conductive agent impregnation process> An ionic conductive agent is applied to the surface of the elastic layer irradiated with ultraviolet light, and the ionic conductive agent is allowed to penetrate to a predetermined depth from the surface (coated surface) of the elastic layer. At this time, if the ionic conductive agent remains on the surface of the elastic layer, it is preferable to wipe it off to prevent further penetration of the ionic conductive agent. As described above, the injection amount of the ionic conductive agent can be adjusted by the cumulative amount of light irradiated with ultraviolet light in the air atmosphere on the surface of the elastic layer and the time from the application of the ionic conductive agent to the wiping off. The specific cumulative amount of light is appropriately adjusted by the ratio of the amount of double bonds and hydrosilyl groups bonded to silicon atoms of the uncured addition-curing silicone rubber used to form the elastic layer. As an example, a mixture of equal amounts (by mass) of liquid A and liquid B of "SE1886" (trade name, manufactured by Dow-Toray) is used as an addition-curing liquid silicone rubber for forming the elastic layer. The cumulative amount of light at a wavelength of 185 nm on the irradiated surface is 800 mJ / cm2 on the surface of the elastic layer formed using an addition-curing liquid silicone rubber composition containing this mixture. 2The elastic layer is irradiated with ultraviolet light for 300 seconds so that the ultraviolet light irradiation surface is equal to or greater than 100 nm. After this, an ionic conductive agent having the structure shown in formula (1) is uniformly applied as an ionic conductive agent to the entire surface of the elastic layer irradiated with ultraviolet light. Then, 30 seconds after the completion of application, the ionic conductive agent remaining on the surface is wiped off to stop further penetration of the ionic conductive agent into the elastic layer.

[0032] After the elastic layer is impregnated with the ion conductive agent, an adhesive layer and a surface layer are formed on the outer periphery of the elastic layer. The adhesive layer may have any thickness that allows it to be formed uniformly, and is applied to a thickness of, for example, about 1 to 10 μm. In this embodiment, an addition-curing silicone rubber adhesive is used as the adhesive layer, but is not limited to this. The surface layer is formed by covering a fluororesin tube whose inner surface has been hydrophilically treated. After covering with the fluororesin tube, the belt surface is uniformly rubbed from above the fluororesin tube to rub out excess addition-curing silicone rubber adhesive from between the elastic layer and the fluororesin tube. This also makes it possible to make the adhesive layer have a uniform thickness.

[0033] <Image forming device> 1 is a schematic cross-sectional view of a color electrophotographic printer, which is an example of an image forming apparatus according to the present embodiment, taken along the sheet transport direction. Hereinafter, the color electrophotographic printer will be simply referred to as the "printer." The printer shown in FIG. 1 is equipped with image forming units 10 for the colors Y (yellow), M (magenta), C (cyan), and Bk (black). This allows color printing and monochrome printing. A photosensitive drum 11 is pre-charged by a charger 12. Then, a latent image is formed on the photosensitive drum 11 by a laser scanner 13. The latent image is turned into a toner image by a developing unit 14. The toner image on the photosensitive drum 11 is sequentially transferred to an image carrier, for example, an intermediate transfer belt 31, by a primary transfer blade 17. After transfer, the toner remaining on the photosensitive drum 11 is removed by a cleaner 15. As a result, the surface of the photosensitive drum 11 becomes clean and is prepared for the next image formation.

[0034] Meanwhile, recording materials (sheets P) are sent out one by one from a paper feed cassette 20 or a multi-paper feed tray 25 and fed into a pair of registration rollers 23. The pair of registration rollers 23 temporarily receives the sheet P and straightens it out if it is skewed. The pair of registration rollers 23 then synchronize with the toner image on the intermediate transfer belt 31 and feeds the sheet P between the intermediate transfer belt 31 and a secondary transfer roller 35. The toner image on the intermediate transfer belt 31 is transferred onto the sheet P by pressure applied by the secondary transfer roller 35 and the opposing roller 34, which are transfer bodies. Thereafter, the toner image T on the sheet P is fixed onto the sheet P as a fixed image T' by the sheet P being heated and pressurized by a fixing device 40.

[0035] Next, the fixing device used in this embodiment will be described. Fig. 2 is a schematic diagram of the fixing device 40, which is a film heating type fixing device (tensionless type). This film heating type is used in this embodiment, but it can also be applied to the surface layer of a roller pair type or film type fixing device.

[0036] Reference numeral 43 denotes a ceramic heater (hereafter referred to as heater) as a heating element. This heater 43 is basically composed of a long and thin ceramic substrate with the longitudinal direction perpendicular to the drawing and an electrically-heated resistor layer provided on the substrate surface, and is a low-heat capacity heater that rises in temperature with a steep rise characteristic as a whole when electricity is passed through the heat-generating resistor layer. In addition, it is configured so that the electrically-heated area can be switched according to the longitudinal width size of the recording material (sheet P). Reference numeral 41 denotes a cylindrical (endless) heat-resistant fixing member serving as a heating member for transmitting heat, and is loosely fitted onto a support member including the heater 43. Fig. 3 is a partially enlarged cross-sectional view of the fixing member 41 in this embodiment, which corresponds to the region G in Fig. 2. This fixing member has a laminated structure of at least a layer structure 41f, an elastic layer 41c, and a base layer 41d.

[0037] Reference numeral 42 denotes a pressure roller having heat resistance and elasticity as a pressure member, which has a core metal 46 and an elastic layer 47 made of heat-resistant rubber such as silicone rubber or fluororubber, or a silicone rubber foam, and is disposed with both ends of the core metal supported by bearings for free rotation. The fixing member 41 and heater 43 are disposed above the pressure roller 42, parallel to the pressure roller 42 with respect to the heater 43 side, and pressed by a pressing member (not shown). As a result, the lower surface of the heater 43 and the upper surface of the pressure roller 42 are pressed against each other via the fixing member 41 against the elasticity of the elastic layer 47 of the pressure roller, forming a fixing nip portion N of a predetermined width as a heating portion.

[0038] The pressure roller 42 is driven to rotate at a predetermined peripheral speed in the counterclockwise direction indicated by the arrow by a driving means (not shown). A rotational force acts on the fixing member 41 due to a pressure frictional force at the fixing nip N between the pressure roller 42 and the fixing member 41 caused by the rotational drive of the pressure roller 42. The inner surface of the fixing member 41 is in close contact with and slides against the lower surface of the heater 43, and the fixing member 41 is driven to rotate in the clockwise direction indicated by the arrow. The support member also serves as a rotation guide member for the fixing member 41.

[0039] The pressure roller 42 is driven to rotate, and the fixing member 41 is driven to rotate accordingly. In addition, the heater 43 is energized to rapidly heat up to a predetermined temperature and is in a temperature-controlled state, and the sheet P carrying the unfixed toner image T is introduced between the fixing member 41 and the pressure roller 42 in the fixing nip N. In the fixing nip N, the toner image-carrying side of the sheet P is in close contact with the outer peripheral surface of the fixing member 41 and is sandwiched and conveyed through the fixing nip N together with the fixing member 41. During this sandwiching and conveying process, the sheet P is heated by the heat from the fixing member 41 heated by the heater 43, and the unfixed toner image T on the sheet P is heated and pressed onto the sheet P, melted, and fixed as a fixed image T'. The sheet P that has passed through the fixing nip N is separated from the outer peripheral surface 41S of the fixing member 41 by a curvature and conveyed to be discharged. Reference numeral 44 denotes a contact thermometer (thermistor), which measures the temperature of the fixing member 41 heated by the heater 43, and transmits the detection result to a temperature control means (not shown). Reference numeral 45 denotes a heater holder, which is a member for holding the heater 43 that has been heated to a high temperature. EXAMPLES

[0040] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0041] The measurement method in this example will be described. (Measurement method 1: Measurement of the penetration depth of ion conductive agent into elastic layer) The prepared fixing belt was cut out using a cryo-ultramicrotome (manufactured by Leica Microsystems) to obtain a cross-sectional sample showing a cross-section of the fixing belt in the thickness direction. In the cross-sectional sample, the cross-section of the elastic layer was analyzed by secondary ion mass spectrometry (SIMS) to measure the distribution and amount of the ionic conductive agent in the elastic layer. Furthermore, the distribution of the ionic conductive agent in the cross-section of the elastic layer was measured to measure the penetration depth of the ionic conductive agent from the surface of the elastic layer. Specifically, the distribution of the ionic conductive agent was measured by mapping the ionic conductive agent in the cross section of the elastic layer using SIMS. In addition, multiple samples were prepared to which a certain amount of ionic conductive agent was added, and a calibration curve was created from the samples to measure the content. Furthermore, the penetration depth of the ionic conductive agent into the elastic layer was measured from the measurement results of the distribution of the ionic conductive agent.

[0042] (Measurement method 2: Measurement of surface resistivity of layer structure and elastic layer) (Measurement of surface resistivity of layer structure) The surface resistivity of the layer structure was measured according to a method in accordance with Japanese Industrial Standards (JIS) K 6271-1:2022. Specifically, the surface resistivity of the outer surface of the surface layer, which is the contact surface with the unfixed toner image of the fixing belt, was measured using a high resistance resistivity meter (product name: Hirester UX MCP-HT800; manufactured by Nitto Seiko Analytech Co., Ltd.) and a ring probe (product name: UR-SS; manufactured by Nitto Seiko Analytech Co., Ltd.). The measurement was performed after applying DC 500V for 20 seconds.

[0043] (Measurement of surface resistivity of elastic layer) A razor was inserted between the elastic layer of the fixing belt and the layer structure, and the layer structure was peeled off to expose the surface of the elastic layer opposite to the side facing the base layer. The surface resistivity of the exposed surface of the elastic layer was measured in the same manner as above.

[0044] (Measurement of layer structure and thickness of elastic layer) The thickness of the layer structure was measured by using a micrometer (high-precision digital micrometer MDH-25MB, manufactured by Mitutoyo Corporation) to measure the thickness of five arbitrary points of the layer structure peeled off from the fixing belt when measuring the surface resistivity of the elastic layer, and the arithmetic average value of the five points was adopted. Furthermore, the thickness of the elastic layer was measured by inserting a razor into the interface between the base layer and the elastic layer of the fixing belt and the interface between the elastic layer and the layer structure, and only the elastic layer was taken out. The thickness of the taken-out elastic layer was measured by using a micrometer (high-precision digital micrometer MDH-25MB, manufactured by Mitutoyo Corporation) to measure the thickness of five arbitrary points of the layer structure, and the arithmetic average value of the five points was adopted.

[0045] (Rating: Image rating) The fixing members produced in each of the Examples and Comparative Examples were applied to the fixing device shown in Fig. 2 to prepare an electrophotographic image forming apparatus (product name: iR-ADV C3835F; manufactured by Canon Inc.) shown in Fig. 1. Images were output using this electrophotographic image forming apparatus under the following conditions. Test environment: room temperature 25℃, humidity 10%, Process speed: 150mm / sec Paper passing conditions: The main body, fixing member, and pressure member were all neutralized with an ionizer. After that, an image forming operation was performed to form a grid image on 100 sheets of copy paper (product name: CS-068; Nippon Paper Industries Co., Ltd., 68g paper) that had been placed in the test environment for 10 days. Then, an image forming operation was performed to form a halftone image on both sides of copy paper (product name: Office70; Nippon Paper Industries Co., Ltd., 70g paper) for 5 sheets in a row.

[0046] The five halftone images obtained were visually observed and evaluated in terms of streaks and image unevenness according to the following criteria. Rank C or higher was judged as acceptable. Here, the streaks are caused by electrostatic offset due to the inhibition of toner releasability of the surface layer caused by the weak charge neutralization effect in the elastic layer, and the image unevenness is caused by current leakage in the layer structure or the elastic layer.

[0047] (Evaluation criteria for lines) Rank A: No streaks. Rank B: Very slight streaks are visible. Rank C: Slight streaks are visible. Rank D: Streaks are clearly visible.

[0048] (Evaluation criteria for image unevenness) Rank A: No image unevenness. Rank B: Image unevenness is very slight. Rank C: Slight image unevenness is observed. Rank D: Image unevenness is clearly observed.

[0049] Example 1 (Method of manufacturing fixing belt) Next, a method for producing the fixing member used in this example will be described. In this example, a fixing belt having a fixing member as shown in FIG. (Process 1) As the base layer, a belt material made of SUS having an endless shape with an inner diameter of 25 mm, a width of 400 mm, and a thickness of 40 μm was prepared. The outer peripheral surface of this belt material was subjected to a primer treatment. (Process 2) As a raw material for forming the elastic layer, an addition-curing liquid silicone rubber (product name: SE1886 (liquid A, liquid B), manufactured by Dow-Toray) that does not contain a filler was prepared. Equal amounts of liquid A and liquid B of "SE1886" were mixed, and spherical alumina (product name: Alnabeads CB-A30S, manufactured by Showa Denko K.K.) was added to this mixture as a spherical filler. Next, an ionic conductive agent (product name: FC-4400, manufactured by 3M Japan Ltd.) ((n-C4H9)3(CH3)N + - N(SO2CF3)2) was added to the composition in an amount of 1.5% by mass. Thus, an addition curing type silicone rubber composition for forming an elastic layer was prepared. After applying these to the outer peripheral surface of the belt material by a ring coating method, the material was heated at a temperature of 200°C for 4 hours to crosslink the layer of the addition curing type silicone rubber composition, thereby forming an elastic layer having a thickness of 300 μm.

[0050] Steps 3 and 4 are steps for permeating the ion conductive agent into the elastic layer of the fixing belt. (Step 3) The belt material on which the elastic layer was formed was rotated in the circumferential direction at a moving speed of 20 mm / sec, and the surface of the elastic layer was irradiated with ultraviolet light in an air atmosphere using an ultraviolet lamp disposed at a distance of 10 mm from the surface of the elastic layer. The ultraviolet lamp was a low-pressure mercury ultraviolet lamp (product name: GLQ500US / 11, manufactured by Toshiba Lighting & Technology Corporation), and irradiation was performed for 300 seconds, resulting in an integrated light amount of 800 mJ / cm2 at a wavelength of 185 nm on the irradiated surface. 2 It was decided. (Step 4) Next, 0.3 mg of an ion conductive agent (product name: FC-4400, manufactured by 3M Japan) was uniformly applied to the entire surface of the elastic layer using a ring coater having a nozzle on the inner circumferential surface. Specifically, the ion conductive agent was applied to the surface of the elastic layer while moving the link coater from one end of the elastic layer to the other end in 10 seconds. 20 seconds after the end of application, a ring member having a scraping portion on the inner circumferential surface was moved from one end of the elastic layer to the other end to wipe off the ion conductive agent remaining on the surface of the elastic layer in 10 seconds. By this process, the time from application of the ion conductive agent to wiping was set to 30 seconds at each position in the longitudinal direction of the elastic layer. This made the penetration depth of the ion conductive agent from the first surface of the elastic layer at each position in the longitudinal direction of the elastic layer uniform. (Step 5) An addition-curing silicone rubber adhesive (product name: SE1819CV, a mixture of equal amounts of "liquid A" and "liquid B" manufactured by Dow Corning Toray Co., Ltd.) was applied to the surface of the elastic layer impregnated with the ionic conductive agent to a thickness of approximately 5 μm. (Step 6) A 20μm fluororesin tube (Gunze 959HP-PLUS (Mitsui-Chemours Fluoroproducts)) with a hydrophilic inner surface was placed over the belt to form a surface layer. The excess addition-curing silicone rubber adhesive was squeezed out from between the elastic layer and the fluororesin tube by uniformly squeezing the belt surface over the fluororesin tube. Then, the fluororesin tube was placed over the adhesive and placed in an electric furnace set at 200°C, where it was heated for one hour to harden the adhesive and bond the fluororesin tube onto the elastic layer. Both ends were then cut to obtain a fixing belt 350 mm wide. When this fixing belt was measured using the method described in Measurement Method 2, the surface resistivity of the layer structure consisting of the adhesive (adhesive layer) and the fluororesin tube (surface layer) was 1×10 15 Ω / □, the surface resistivity of the elastic layer is 1×10 14 It was Ω / □.

[0051] Example 2 In step 2 of Example 1, the amount of the ion conductive agent added was set to 0.5 mass %. Except for this, a fixing belt was produced in the same manner as in Example 1.

[0052] Example 3 A fixing belt was produced in the same manner as in Example 1 except that no ion conductive agent was added in step 2 of Example 1.

[0053] Example 4 In step 3 of Example 1, the irradiation time of ultraviolet light to the first surface of the elastic layer before applying the ion conductive agent was set to 150 seconds. A fixing belt was produced in the same manner as in Example 1.

[0054] Comparative Example 1 In step 2 of Example 1, the amount of the ionic conductive agent added was 5.0 mass %. In addition, step 4 of Example 1 was not performed. In other words, the elastic layer was not impregnated with the ionic conductive agent. Other than that, a fixing belt was produced in the same manner as in Example 1.

[0055] Comparative Example 2 The ion conductive agent was not added in step 2 of Example 1. Also, step 4 of Example 1 was not performed. Except for the above, a fixing belt was produced in the same manner as in Example 1.

[0056] Comparative Example 3 The impregnation depth of the ion conductive agent from the first surface of the elastic layer was increased by extending the time from application of the ion conductive agent to the surface of the elastic layer to wiping it off to 100 seconds in step 4 of Example 1. Otherwise, a fixing belt was produced in the same manner as in Example 1.

[0057] Comparative Example 4 The crosslink density of the silicone rubber on the first surface of the elastic layer was increased by irradiating the first surface of the elastic layer with ultraviolet light for 600 seconds before applying the ionic conductive agent in step 3 of Example 1. A fixing belt was produced in the same manner as in Example 1.

[0058] Comparative Example 5 In step 2 of Example 1, 15% by mass of carbon black was added instead of the ion conductive agent. Except for this, a fixing belt was produced in the same manner as in Example 1.

[0059] Comparative Example 6 A fixing belt was produced in the same manner as in Example 1 except that a fluororesin tube containing carbon black was used in step 6 of Example 1.

[0060] Table 1 shows the measurement and evaluation results of the fixing belts produced in Examples 1 to 4 and Comparative Examples 1 to 6.

[0061] [Table 1]

[0062] When the fixing belts produced by the methods described in Examples 1 to 4 were used, electrostatic offset and image defects could be suppressed.

[0063] In contrast, in Comparative Example 1, since the first region was not provided, image unevenness occurred due to current leakage caused by aggregation of the ion conductive agent in the elastic layer. In Comparative Example 2, since the elastic layer did not contain an ion conductive agent and the charge neutralization effect of the elastic layer (first region) was not obtained, it is believed that electrostatic offset occurred due to charge accumulation on the fixing belt. In Comparative Example 3, the ionic conductive material penetrated beyond the first region, so that the ionic conductive material coagulated in the elastic layer, causing current leakage and resulting in image unevenness. In Comparative Example 4, since the content of the ion conductive agent in the first region was small, the charge neutralization effect of the elastic layer (first region) was weak, which is considered to have caused electrostatic offset. It is believed that the carbon black aggregated in the elastic layer in Comparative Example 5, causing the current leak, and that the carbon black aggregated in the surface layer (layer structure) in Comparative Example 6, causing the current leak.

[0064] The present disclosure includes the following configurations. [Configuration 1] A fixing member having a base layer, an elastic layer on the base layer, and a layer structure on a surface of the elastic layer opposite to a surface facing the base layer, The layer structure includes at least a surface layer that constitutes an outer surface of the fixing member, The thickness of the layer structure is 100 μm or less, The surface resistivity of the layer structure measured on the surface opposite to the side facing the base layer is 1×10 15 Ω / □ or more, The thickness of the elastic layer is 100 μm or more, The surface resistivity of the elastic layer measured on a first surface facing the layer structure is 1×10 14 Ω / □ or more, A fixing member, wherein a first region of the elastic layer extending from the first surface to a position at a depth of 10 μm contains an ion conductive agent in an amount of 5.0% by mass or more based on the mass of the elastic layer. [Configuration 2] The fixing member described in [Structure 1], wherein the content of the conductive agent in a second region from a position 10 μm deep from the first surface of the elastic layer to a second surface of the elastic layer opposite the first surface is 0 mass % or more and 0.5 mass % or less, based on the mass of the elastic layer. [Configuration 3] The fixing member according to [Configuration 2], wherein the second region does not contain a conductive agent. [Configuration 4] The fixing member according to any one of [Configuration 1] to [Configuration 3], wherein the ionic conductive agent is an ionic liquid having a chemical structure represented by the following formula (1). (n-C4H9)3(CH3)N + · - N(SO2CF3)2(1) [Configuration 5] The fixing member according to any one of [Configuration 1] to [Configuration 4], wherein the layer structure includes an adhesive layer. [Configuration 6] The fixing member according to any one of [Configuration 1] to [Configuration 5], wherein the surface layer contains a fluorine resin. [Configuration 7] A fixing device including a fixing member, a pressure member that applies pressure to an outer peripheral surface of the fixing member to form a nip portion with the fixing member, and a heating member that heats the fixing member, wherein the fixing member is the fixing member according to any one of [Configuration 1] to [Configuration 6]. [Configuration 8] [Configuration 7] An electrophotographic image forming apparatus comprising the fixing device according to the present invention. [Explanation of symbols]

[0065] 1. Electrophotographic image forming apparatus 40 Fixing device 41 Fixing member 41a Surface layer 41b Adhesive layer 41c Elastic layer 41d base layer 41f layer structure 41g 1st area 41h 2nd area 41S outer surface 42 Pressure roller 43 Heater 44 Contact thermometer 45 Heater holder P Recording material T Toner N Fixing nip

Claims

1. A fixing member having a base layer, an elastic layer on the base layer, and a layer structure on a surface of the elastic layer opposite to a surface facing the base layer, The layer structure includes at least a surface layer that constitutes an outer surface of the fixing member, The thickness of the layer structure is 100 μm or less, The surface resistivity of the layer structure measured on the surface opposite to the side facing the base layer is 1×10 １5 Ω / □ or more, The thickness of the elastic layer is 100 μm or more, The surface resistivity of the elastic layer measured on a first surface facing the layer structure is 1×10 １４ Ω / □ or more, and A fixing member, wherein a first region of the elastic layer extending from the first surface to a position at a depth of 10 μm contains an ion conductive agent in an amount of 5.0% by mass or more based on the mass of the elastic layer.

2. 2. The fixing member according to claim 1, wherein the content of the conductive agent in a second region from a position 10 μm deep from the first surface of the elastic layer to a second surface of the elastic layer opposite the first surface is 0 mass % or more and 0.5 mass % or less, based on the mass of the elastic layer.

3. The fuser member of claim 2 , wherein the second region is free of conductive agent.

4. The fixing member according to claim 1 , wherein the ionic conductive agent is an ionic liquid having a chemical structure of the following formula (1): (n-C ４ H ９ ) ３ (CH ３ )N ＋ ・ － N(SO ２ CF ３ ) ２ (1)

5. The fuser member of claim 1 , wherein the layer structure comprises an adhesive layer.

6. The fixing member of claim 1 , wherein the surface layer comprises a fluororesin.

7. A fixing device comprising a fixing member, a pressure member that presses the outer peripheral surface of the fixing member to form a nip portion with the fixing member, and a heating member that heats the fixing member, wherein the fixing member is the fixing member described in any one of claims 1 to 6.

8. An electrophotographic image forming apparatus comprising the fixing device according to claim 7 .

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