JP6976764B2 - Manufacturing method of fixing member - Google Patents

Description

The present invention relates to a method for producing a constant Chakubuzai.

Generally, in a heating fixing device used in an electrophotographic method such as a copying machine or a laser printer, a pair of heated rollers and rollers, a film and a roller, a belt and a roller, and a belt and a belt are pressed against each other. .. A recording medium in which an image formed of unfixed toner (hereinafter, also referred to as “unfixed toner image”) is supported on a pressure contact portion (hereinafter, also referred to as “fixing nip portion”) formed between the rotating bodies. Is introduced, and the unfixed toner is heated and melted to be fixed on the recording medium.

The rotating body in contact with the unfixed toner image held on the recording medium is called a fixing member, and is called a fixing roller, a fixing film, a fixing belt, or the like depending on its shape.

With the recent colorization and image quality improvement, it is necessary to wrap multicolored toner in the fixing nip portion to melt and mix the colors. Therefore, as a configuration of these fixing members, an elastic layer having heat resistance such as silicone rubber is adhesively formed on the outer surface of the base layer, and a fluororesin mold release layer having good mold releasability of a toner such as fluororesin is further formed on the outer surface. A multi-layered fixing member formed is widely used.

Due to the excellent elastic deformation of the silicone rubber elastic layer, the fixing member having the above structure wraps and melts the toner image without excessively crushing the toner image at the fixing nip, and also follows the unevenness of the fibers of the paper which is the recording medium. It has the effect of preventing the occurrence of uneven melting of toner.

However, the fluororesin mold release layer as the mold release layer on the outer surface of the silicone rubber elastic layer has a high elastic modulus and is rigid as compared with the silicone rubber elastic layer. Therefore, depending on the thickness and elastic modulus of the fluororesin release layer, the surface hardness of the fixing member may increase, and the above-mentioned advantageous effects brought about by the elastic deformation of the silicone rubber elastic layer may not be sufficiently exhibited. Therefore, it is useful to take measures such as thinning the fluororesin release layer or lowering the elastic modulus so as not to impair the flexibility of the silicone rubber elastic layer.

Therefore, Patent Document 1 discloses a fixing member using a surface layer coated with a fluororesin of 10 to 15 μm as a release layer from the viewpoint of thinning the surface layer.

Further, in Patent Document 2, from the viewpoint of lowering the elastic modulus of the surface layer, PFA having a perfluoroalkyl vinyl ether (PAVE) ratio of 3.0 mol% or more and 5.8 mol% or less has a crystalline property. It is described that it is low and exhibits a flexible rubber state at a temperature at the time of heat fixing, for example, a temperature of 150 ° C.

Japanese Unexamined Patent Publication No. 2013-130731 Japanese Unexamined Patent Publication No. 2016-95475

Regarding the fluororesin coating of the thin film of Patent Document 1, there are problems that the strength of the release layer after film formation is weaker and the surface smoothness is poor as compared with the fluororesin tube.

As described in Patent Document 2, PFA having a perfluoroalkyl vinyl ether (PAVE) ratio of 3.0 mol% or more and 5.8 mol% or less is highly flexible, and therefore it is used as a release layer. It can be said that the fixing member used in the above is preferable in that the surface thereof can be made to follow the unevenness of the surface of the paper well.

By the way, as a method for obtaining a fixing member having a release layer made of PFA (hereinafter, also referred to as "soft PFA") having a PAVE ratio of 3.0 mol% or more and 5.8 mol% or less, the PFA is used. A method of adhering a fluororesin tube formed by extrusion molding to the surface of an elastic layer using a silicone rubber adhesive can be considered.

In the fluororesin tube formed by extrusion molding, the molecular chains of PFA are oriented in a direction parallel to the extrusion direction. Therefore, the thermal conductivity in the thickness direction is lower than the thermal conductivity in the direction parallel to the extrusion direction, and as the number of heat-fixed sheets increases, cracks may occur in the longitudinal direction of the fluororesin tube. there were. This tendency becomes remarkable because the thinner the PFA, the easier it is for the molecular orientation to be parallel to the extrusion direction.

Therefore, as a result of diligent studies by the present inventors, the thickness of the extruded tube made of PFA such as soft PFA is relaxed by annealing the extruded tube at a temperature higher than the melting point to relax the orientation of the molecular chain in the extrusion direction. It has been found that the thermal conductivity in the direction can be improved and the generation of cracks in the longitudinal direction can be suppressed. However, when a tube made of PFA, which is bonded to the surface of an elastic layer containing silicone rubber via a thin silicone rubber adhesive or the like, is annealed, the PFA heated to a temperature higher than the melting point has fluidity. It was found that, depending on the surface condition of the underlying elastic layer, the smoothness of the finished fixing belt surface may be impaired by following the unevenness of the surface condition of the elastic layer. ..

INDUSTRIAL APPLICABILITY According to the present invention, uneven melting of toner is suppressed by improving the followability of paper fibers to unevenness, fixing property is improved by improving heat transfer property of the fluororesin release layer, and gloss reduction of output image is suppressed by maintaining smoothness of the surface of the fixing member. Another object of the present invention is to provide a method for manufacturing a fixing member, which can easily manufacture a fixing member capable of suppressing cracks in the longitudinal direction due to an increase in the number of heat-fixing sheets.

The above object is achieved by a method for manufacturing a fixing member according to the present invention. According to an embodiment of the present invention, manufacturing how constant Chakubuzai that having a following features are provided.
(Feature 1)
A method for manufacturing a fixing member having at least a base layer, an elastic layer containing a filler, a fluororesin release layer, and an adhesive layer for adhering the elastic layer and the fluororesin release layer, and the average particle size of the total filler. The step of forming the elastic layer having a thickness of 10 μm or less and the average sphericity of the filler of 0.8 or more on the base layer, and the polymerization ratio of the perfluoroalkyl vinyl ether are 3.0 mol% or more and 5.8 mol% or less. in is a step of forming a tubular shaped body by extruding fluororesin tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, said through an adhesive layer covering the tubular shaped body in the elastic layer, the fluorine The fluororesin release layer has a step of adhering the tubular molded body by heat fusion by heating to a temperature equal to or higher than the melting point of the resin, and the fluororesin release layer has an orientation degree of 35% or less and an arithmetic average roughness Ra of the surface. it is 0.05μm or less, the production method of the fixing member, characterized in that.

According to the present invention, uneven melting of toner is suppressed by improving the followability of paper fibers to unevenness, fixing property is improved by improving the heat transfer property of the fluororesin release layer, and gloss of the output image is maintained by maintaining the smoothness of the surface of the fixing member. It is possible to easily manufacture a fixing member capable of suppressing reduction and suppressing cracks in the longitudinal direction due to an increase in the number of heat-fixed sheets.

Schematic cross-sectional view of one form of the fixing member according to the present invention. The figure which shows the example of the relationship between the thickness of a fluororesin release layer and the thermal conductivity in the thickness direction. Schematic diagram of a cross section of a form of a fixing device using the fixing member according to the present invention. Schematic diagram of a cross section of an electrophotographic image forming apparatus using the fixing member according to the present invention.

The fixing member, the heat fixing device, and the image forming device according to the present invention will be described in detail below based on a specific configuration, but the scope of the present invention is not limited to this embodiment, and the gist of the present invention is used. The present invention also includes those modified to the extent that the above is not impaired.

(1) Schematic configuration of the fixing belt FIG. 1 is a schematic cross-sectional view showing one form of the fixing member according to the present invention. In the fixing belt 1 as a cylindrical fixing member, the inner surface sliding layer 1a is arranged on the inner peripheral surface of the cylindrical base material 1b. The inner surface sliding layer is provided to improve the slidability between the fixing belt 1 and the pressing member, and the inner surface sliding layer 1a is omitted when it is not necessary to particularly improve the slidability. It may be done.

The elastic layer 1d is provided on the base material. Specifically, the outer peripheral surface of the cylindrical base material 1b is covered with the silicone rubber elastic layer 1d arranged via the primer layer 1c. A fluororesin mold release layer 1f is arranged on the silicone rubber elastic layer 1d via the silicone rubber adhesive layer 1e. Each member will be specifically described below.

(2) Cylindrical base material Since the fixing belt 1 is required to have heat resistance, it is preferable to use a cylindrical base material 1b in consideration of heat resistance and bending resistance. For example, as the metal base material, a nickel electroformed base material or the like can be used as disclosed in JP-A-2002-258648, International Publication No. 05/054960, and JP-A-2005-121825. .. As the heat-resistant resin base material, a polyimide resin, a polyamide-imide resin, a polyetheretherketone resin and the like can be used as disclosed in JP-A-2005-300915 and JP-A-2010-134094.

(3) Inner Surface Sliding Layer and Method for Forming the Inner Surface Sliding Layer A resin having high durability and high heat resistance such as a polyimide resin, a polyamide-imide resin, and a polyetheretherketone resin is suitable for the inner surface sliding layer 1a. In particular, a polyimide resin is preferable from the viewpoints of ease of production, heat resistance, elastic modulus, strength and the like. The polyimide resin layer can be formed as follows. That is, a polyimide precursor solution obtained by reacting an aromatic tetracarboxylic acid dianhydride or a derivative thereof with an approximately equimolar amount of an aromatic diamine in an organic polar solvent is applied to the inner surface of the cylindrical substrate. It can be formed by drying, heating, and dehydrating and ring-closing reaction.

As a coating method, a method such as a ring coat method is possible. After the polyimide precursor solution is applied to the inner surface of the cylindrical base material 1b, the cylindrical base material coated on the inner surface is left to dry in, for example, a hot air circulation furnace at 60 ° C. for 30 minutes. Then, by leaving this in a hot air circulation furnace at 200 ° C. to 240 ° C. for 10 to 60 minutes and firing it, a polyimide inner surface sliding layer can be formed by a dehydration ring closure reaction.

(4) Silicone rubber elastic layer and its forming method The silicone rubber elastic layer 1d functions as an elastic layer to be supported on the fixing member in order to give uniform pressure to the toner image and the unevenness of the paper at the time of fixing. In order to exhibit such a function, the silicone rubber elastic layer 1d is not particularly limited, but it is preferable that the addition-curable silicone rubber is cured in view of processability.

Generally, the addition-curable silicone rubber contains an organopolysiloxane having an unsaturated aliphatic group, an organopolysiloxane having an active hydrogen bonded to silicon, and a platinum compound as a cross-linking catalyst.

The organopolysiloxane having active hydrogen bonded to silicon forms a crosslinked structure by the reaction with the alkenyl group of the organopolysiloxane component having an unsaturated aliphatic group by the catalytic action of the platinum compound.

The silicone rubber elastic layer 1d contains a filler for improving the thermal conductivity, reinforcement, heat resistance, etc. of the fixing member.

In particular, for the purpose of improving thermal conductivity, a filler having high thermal conductivity is preferable. Specific examples thereof include inorganic substances, particularly metals and metal compounds.

Specific examples of the high thermal conductive filler, silicon carbide (SiC), silicon nitride _{(Si 3 N} 4), boron nitride (BN), aluminum nitride (AlN), alumina _{(Al 2 O} 3), zinc oxide (ZnO), Examples thereof include magnesium oxide (MgO), silica (SiO ₂ ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni) and the like. These can be used alone or in combination of two or more.

The average particle size of the high thermal conductive filler is preferably 10 μm or less in order to suppress the arithmetic average roughness Ra of the fixing belt 1 after the surface annealing step described later to 0.05 μm or less. Further, the shape is spherical, pulverized, plate-shaped, whisker-shaped or the like, but spherical ones are preferable from the viewpoint of surface smoothness and dispersibility, and among them, those having a sphericity of 0.8 or more are more preferable. ..

From the viewpoint of contribution to the surface hardness of the fixing member and the efficiency of heat conduction to the unfixed toner at the time of fixing, the preferable range of the thickness of the silicone rubber elastic layer 1d is 100 μm or more and 500 μm or less, and particularly 200 μm or more and 400 μm or less. Is preferable.

Regarding the silicone rubber elastic layer 1d, processing methods such as a mold forming method, a blade coating method, a nozzle coating method, and a ring coating method are disclosed in JP-A-2001-62380 and JP-A-2002-21432. It is widely known. The silicone rubber elastic layer 1d can be formed by heating and cross-linking the raw material mixture supported on the base material by these methods.

In order to improve the adhesiveness between the cylindrical base material 1b and the silicone rubber elastic layer 1d, it is desirable that the cylindrical base material 1b is pre-primed. The primer used at this time is required to have better wettability with the cylindrical base material 1b than the silicone rubber elastic layer 1d. Examples of such a primer include a hydrosilyl-based (SiH-based) silicone primer, a vinyl-based silicone primer, and an alkoxy-based silicone primer. The thickness of the primer layer 1c is preferably such that it exhibits adhesive performance while reducing unevenness, and is preferably about 0.5 μm or more and 3 μm or less.

In order to suppress the arithmetic mean roughness Ra of the fixing belt 1 after the surface layer annealing step described later to 0.05 μm or less, the arithmetic average roughness Ra of the silicone rubber elastic layer 1d is required to be 1.7 μm or less. In order to reduce the arithmetic average roughness Ra to 1.7 μm or less, for example, the sphericity and the particle size of the filler that causes the surface of the silicone rubber elastic layer 1d to be roughened should be restricted. Can be achieved with. More specifically, it can be achieved when the average particle size of the filler blended in the cured silicone rubber is 10 μm or less and the average sphericity is 0.8 or more. It can also be achieved by forming the silicone rubber elastic layer 1d and then smoothing it with a wrapping film or the like.

(5) Fluororesin mold release layer and its formation method The fluororesin mold release layer 1f is a layer having an important function in ensuring image uniformity together with the silicone rubber elastic layer 1d. The fluororesin release layer 1f is a layer made of fluororesin.

As the fluororesin, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) having excellent heat resistance is preferably used.

As described above, fluororesin is a material that has been used for a long time in fixing members for the purpose of ensuring the releasability of toner. In general, among tetrafluoroethylene / perfluoroalkyl vinyl ether copolymers (PFA), those having a polymerization ratio of perfluoroalkyl vinyl ether (hereinafter, also referred to as PAVE) of 2 mol% or less are often used. The PAVE skeleton portion inhibits the crystallization brought about by the skeleton portion of the copolymer in tetrafluoroethylene (hereinafter, also referred to as TFE). Therefore, the PAVE skeleton portion is mainly present in the amorphous portion of PFA. Therefore, by setting the polymerization ratio of PAVE to 3.0 mol% or more and 5.8 mol% or less, it is possible to form a large amount of amorphous portions, which is preferable. When the PAVE is less than 3.0 mol%, a large amount of crystal portions formed by the PTFE (polytetrafluoroethylene) skeleton are formed, so that the flexibility is lowered, and as a result, the followability to the paper fiber is lowered. On the other hand, if it exceeds 5.8 mol, the elastic modulus of PFA becomes too low and the wear resistance becomes low.

The glass transition temperature of PFA depends on its composition, but is generally around 100 ° C. At around 150 ° C., which is the actual operating temperature range of the fixing member, the PFA is above the glass transition temperature, and therefore exists in a so-called rubber state. PFA having a polymerization ratio of PAVE of 3.0 mol% or more and 5.8 mol% or less can exist more flexibly in the vicinity of the fixing temperature because the amorphous portion is larger than that of general PFA. Become. The structure of this release layer (fluororesin release layer), in combination with the structure of the silicone rubber elastic layer 1d, makes it possible to reduce uneven melting of the toner.

Further, as PAVE, generally, there are perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE) and the like, but PEVE is more preferred. This is because PEVE is superior to PMVE and PPVE in terms of increasing flexibility in the operating temperature range without lowering the rigidity in the room temperature range, easiness of synthesis, and cracking due to stress cracks.

As a method for synthesizing PFA, a known technique can be used, and for example, the method disclosed in JP-A-2004-161921 can be used for synthesizing PFA.

Examples of the means for forming the fluororesin release layer 1f include a method of coating the surface of the silicone rubber elastic layer 1d with the surface of the silicone rubber elastic layer 1d via an adhesive 1e.

Specifically, for example, the fluororesin release layer 1f can be formed as follows. That is, the addition hardening type silicone rubber adhesive 1e is applied to the surface on the silicone rubber elastic layer 1d described above. The outer surface is coated with the fluororesin tube 1f and laminated. The coating method is not particularly limited, and a method of coating the additive silicone rubber adhesive 1e as a lubricant, a method of coating the fluororesin tube 1f while expanding it from the outside, and the like can be used.

The excess additive-curable silicone rubber adhesive 1e remaining between the cured silicone rubber elastic layer 1d and the fluororesin release layer 1f is removed by scraping it out by using an appropriate means. The thickness of the adhesive layer 1e after being squeezed out is preferably 10 μm or less so as not to impair the heat transfer property. The addition-curing silicone rubber adhesive 1e is an addition-curing silicone rubber containing a self-adhesive component typified by a silane having a functional group such as an acryloxy group, a hydrosilyl group (SiH group), an epoxy group, and an alkoxysilyl group. include. Then, by heating with a heating means such as an electric furnace for a predetermined time, the addition-curable silicone rubber adhesive 1e is cured to form an adhesive layer 1e.

Prior to these bonding steps, the inner surface of the fluororesin tube 1f is previously subjected to sodium treatment, excimer laser treatment, ammonia treatment, or the like to improve the adhesiveness. Further, as disclosed in Japanese Patent Application Laid-Open No. 2009-244887, the silicone rubber elastic layer 1d may be appropriately treated with ultraviolet rays. The purpose of the ultraviolet treatment is to suppress the excessive penetration of the addition-curing silicone rubber adhesive 1e into the silicone rubber elastic layer 1d and maintain the elasticity of the lower silicone rubber elastic layer 1d to improve the surface hardness of the fixing member. Keep it in moderation.

(6) Alignment relaxation treatment of the fluororesin tube and maintenance of smoothness of the fixing member After coating the fluororesin tube 1f, the fluororesin can be further heated to a temperature equal to or higher than the melting point to relax the molecular orientation of the fluororesin tube 1f. is necessary. This is because, due to the nature of the fluororesin tube 1f being molded by extrusion molding, the thinner the thickness, the more the molecular orientation is in the longitudinal direction (MD) during molding. As a result, the thermal conductivity in the thickness direction decreases as shown in the triangular (Δ) plot in FIG. 2 (graph showing an example of the relationship between the thickness of the fluororesin release layer 1f and the thermal conductivity in the thickness direction). Is. In addition, cracks in the molecular orientation direction are likely to occur. By heating the fluororesin tube 1f above its melting point to relax the orientation during molding, the thermal conductivity in the thickness direction can be increased as shown in the square (□) plot in FIG. In addition, the generation of cracks can be suppressed by relaxing the orientation.

However, depending on the surface condition of the underlying elastic layer 1d by the annealing treatment, the PFA has fluidity during the annealing treatment, and the surface of the fixing belt 1 is completed by imitating the unevenness of the surface condition of the elastic layer 1d. The smoothness of the is impaired. The surface smoothness of the fixing belt 1 is closely related to the gloss of the fixing image, and if the arithmetic average roughness Ra of the surface of the fixing member is high, the gloss becomes low. Therefore, in order to obtain a high-gloss fixing image, it is important to set the arithmetic average roughness Ra of the surface of the fixing member to 0.05 μm or less. Therefore, in the present invention, as described above, the arithmetic average roughness Ra of the silicone rubber elastic layer 1d is set to 1.7 μm or less. As a result, the PFA has fluidity in the surface layer annealing treatment, and the arithmetic average roughness Ra of the fixing belt 1 can be suppressed to 0.05 μm or less even if the surface property changes as compared with that before the annealing treatment.

After covering with the fluororesin tube 1f and heating to a temperature higher than the melting point to relax the orientation of the fluororesin tube 1f, the fixing belt 1 can be obtained by cutting both ends to a desired length.

(7) Outline of the structure of the fixing device;
FIG. 3 is a schematic cross-sectional view of a form of the fixing device according to the present invention. This fixing device includes the fixing member described above and a heating means for heating the fixing member. As the heating means, a heating means known in the field of the fixing device, for example, an electric heater can be appropriately used. Here, the fixing belt 1 is a fixing member, and the fixing heater 2 is a heating means.

The fixing device 100 has the above-mentioned fixing belt 1. A pressure roller 6 as a pressure member forming the fixing nip portion 14 with the fixing belt 1 is arranged. A fixing heater 2 is arranged as a nip portion forming member / heating body, and a film guide / heater holder 4 having heat resistance is arranged. The fixing heater 2 is fixed to the lower surface of the film guide / heater holder 4 along the longitudinal direction of the film guide / heater holder 4, and the fixing belt 1 and the heating surface of the fixing heater are slidable. The fixing belt 1 is externally fitted to the film guide / heater holder 4 with some degree of freedom. The film guide / heater holder 4 is made of a liquid crystal polymer resin having high heat resistance, and plays a role of holding the fixing heater 2 and forming the fixing belt 1 into a shape for separating the fixing belt 1 from the recording medium P. The pressure roller 6 has a multilayer structure in which a silicone rubber layer and a PFA resin tube are sequentially laminated on a metal core metal. Both ends of the core metal of the pressure roller 6 are rotatably held between the side plates on the back side and the front side (not shown) of the apparatus frame 13. A fixing unit including a fixing heater 2, a film guide / heater holder 4, a fixing belt stay 5, and a fixing belt 1 is installed on the upper side of the pressurizing roller 6. This fixing unit is installed in parallel with the pressurizing roller 6 with the fixing heater 2 side facing downward. Both ends of the fixing belt stay 5 are urged by a pressurizing roller 6 with a predetermined force (for example, a force of 156.8N (16kgf) and a total pressure of 313.6N (32kgf)) on one end side thereof by a pressurizing mechanism (not shown). ing. As a result, the lower surface (heating surface) of the fixing heater 2 is pressed against the silicone rubber elastic layer 1d of the pressure roller 6 with a predetermined pressing force via the fixing belt 1 to fix the fixing with a predetermined width required for fixing. The nip portion 14 is formed. The thermistor 3 (heater temperature sensor) as a temperature detecting means is installed on the back surface (the surface opposite to the heating surface) of the fixing heater 2 which is a heat source, and has a function of detecting the temperature of the fixing heater 2. The pressure roller 6 is rotationally driven in the direction of the arrow at a predetermined peripheral speed. The fixing belt 1 which is in a pressure-contacted relationship with this is driven by the pressure roller 6 and rotates at a predetermined speed. At this time, the inner surface of the fixing belt 1 is in close contact with the lower surface of the fixing heater 2 and slides, and the outer circumference of the film guide / heater holder 4 is driven to rotate in the direction of the arrow.

A semi-solid lubricant (hereinafter referred to as grease) composed of a solid component (compound) and a base oil component (oil) is applied to the inner surface of the fixing belt 1, and the slidability between the film guide / heater holder 4 and the inner surface of the fixing belt 1 Is secured. Examples of the compound of the semi-solid lubricant include solid lubricants such as graphite and molybdenum disulfide, metal oxides such as zinc oxide and silica, and fluororesins such as PFPE (perfluoropolyether) and PTFE. Examples of the base oil component include heat-resistant polymer resin oils such as silicone oil and fluorosilicone oil. For example, grease using PTFE powder fine particles (particle size 3 μm) as a compound and fluorosilicone oil as an oil is used.

The thermistor 3 is arranged so as to be in contact with the back surface of the fixing heater 2, and is connected to a control circuit unit (CPU) 10 as a control means via an A / D converter 9. The control circuit unit (CPU) 10 has a configuration in which the output from each thermistor is sampled at a predetermined cycle, and the temperature information obtained in this way is reflected in the temperature control. That is, the control circuit unit (CPU) 10 determines the temperature control content of the fixing heater 2 based on the output of the thermistor 3. The heater drive circuit unit 11, which is a power supply unit, plays a role of controlling the energization of the fixing heater 2 so that the temperature of the fixing heater 2 becomes the target temperature (set temperature). Further, the control circuit unit (CPU) 10 is connected to the drive motor of the pressurizing roller 6 via the A / D converter 9. The fixing heater has an alumina substrate and a resistance heating element provided on the substrate and coated with a conductive paste containing a silver-palladium alloy in a uniform film thickness of about 10 μm by a screen printing method. There is. Further, a glass coat made of pressure-resistant glass is applied on the glass to form a ceramic heater. The drive motor of the pressurizing roller 6 is driven by the motor drive circuit unit 12.

The recording medium P on which the unfixed toner image t is formed is guided by the inlet guide 7, passed through the fixing nip portion 14, and discharged from the fixing device 100 by the fixing paper ejection roller 8.

(8) Schematic configuration of the image forming apparatus FIG. 4 is a schematic cross-sectional view of one form of the electrophotographic image forming apparatus according to the present invention. Reference numeral 101 denotes a photosensitive drum as an image carrier, which is rotationally driven at a predetermined process speed (peripheral speed) in the counterclockwise direction of the arrow. The photosensitive drum 101 is charged to a predetermined polarity by a charging device 102 such as a charging roller in the rotation process. Next, the laser beam 103 output from the laser optical system 110 is exposed to the charged surface based on the input image information. The laser optical system 110 outputs a laser beam 103 modulated (on / off) corresponding to a time-series electric digital pixel signal of target image information from an image signal generator such as an image reading device (not shown), and is exposed to light. The 101 surface of the drum is scanned and exposed. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 101 by this scanning exposure. A deflection mirror 109 is used to deflect the output laser beam 103 from the laser optical system 110 to the exposure position of the photosensitive drum 101. Then, the electrostatic latent image formed on the photosensitive drum is visualized (developed) with yellow toner by the yellow developer 104Y in the developing device 104. This yellow toner image is first transferred to the surface of the intermediate transfer drum 105 in the primary transfer unit T1 which is a contact portion between the photosensitive drum 101 and the intermediate transfer drum 105. The toner remaining on the surface of the photosensitive drum 101 is cleaned by the cleaner 107.

The process cycle of charging, exposure, development, primary transfer, and cleaning as described above is a magenta toner image (developer 104M operates), cyan toner image (developer 104C operates), and black toner image (developer 104K operates). ) Is repeated in the same manner. The toner images of each color sequentially formed on the intermediate transfer drum 105 in this way are collectively secondarily transferred onto the recording medium P by the secondary transfer unit T2 which is the contact portion with the transfer roller 106. Toner. The toner remaining on the intermediate transfer drum 105 is cleaned by the toner cleaner 108. The cleaner 108 is in contact with and detachable from the intermediate transfer drum 105, and is configured to be in contact with the intermediate transfer drum 105 only when the intermediate transfer drum 105 is cleaned. Further, the transfer roller 106 is also capable of being brought into contact with and separated from the intermediate transfer drum 105, and is configured to be in contact with the intermediate transfer drum 105 only during the secondary transfer. The recording medium P that has passed through the secondary transfer unit T2 is introduced into the fixing device 100 as an image heating device, and receives a fixing treatment (image heating treatment) of an unfixed toner image carried on the fixing device 100. Then, the recording medium P that has undergone the fixing process is discharged to the outside of the machine, and a series of image forming operations is completed.

[Example 1]
A fixing member having the structure shown in FIG. 1, particularly a fixing belt, was manufactured. As the base material, an endless cylindrical base material having an inner diameter φ (diameter) of 30 mm, a thickness of 40 μm, and a length of 400 mm made of a nickel-iron alloy disclosed in International Publication No. 05/054960 was used.

As a polyimide precursor solution, a polyimide precursor composed of 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride and paraphenylenediamine diluted 5-fold (mass basis) with N-methyl-2-pyrrolidone. Prepared. This precursor solution was applied to the inner surface of the cylindrical substrate by a ring coating method and calcined at 200 ° C. for 20 minutes to imidize the inner surface to form an inner sliding layer having a thickness of 15 μm.

The surface of the cylindrical substrate is coated with a hydrosilyl silicone primer "Shin-Etsu Chemical; DY39-051 A / B (trade name)" and fired at 200 ° C. for 5 minutes to form a primer layer with a film thickness of 1 μm. Obtained.

An addition-curable silicone rubber having a thickness of 300 μm was applied to the outside thereof and fired at 200 ° C. for 30 minutes. At this time, the stock solution of the addition-curable silicone rubber contains the following materials (a) and (b) so that the ratio of the number of vinyl groups (H / Vi) to the Si—H groups is 0.45. A platinum compound having an average particle size of 8.0 μm as a functional filler, 40 vol% of spherical alumina having an average sphericity of 0.9, 2 vol% of anatase-type titanium oxide as a radical trapping agent for imparting heat resistance, and a catalytic amount. Obtained by adding. The average sphericity and the average particle size were obtained by the method described later.
(A) Vinylized polydimethylsiloxane having two or more vinyl groups in one molecule (weight average molecular weight 100,000 (polystyrene equivalent));
(B) Hydrogen organopolysiloxane having two or more Si—H bonds in one molecule (weight average molecular weight 1500 (polystyrene equivalent)).

The arithmetic average roughness Ra of the endless belt formed up to the silicone rubber elastic layer 1d was confirmed by the surface roughness measurement described later. After that, while rotating the endless belt formed up to the silicone rubber elastic layer 1d at a moving speed of 20 mm / sec in the circumferential direction, the elastic layer 1d is irradiated with ultraviolet rays using an ultraviolet lamp installed at a distance of 10 mm from the surface. I did it. As the ultraviolet lamp, a low-pressure mercury ultraviolet lamp (trade name: GLQ500US / 11; manufactured by Harison Toshiba Lighting Co., Ltd.) was used, and irradiation was performed at 100 ° C. for 5 minutes in an atmospheric atmosphere.

After cooling this to room temperature, an additional curing type silicone rubber adhesive 1e (trade name: SE1819CV; "A solution" and "B solution" manufactured by Toray Dow Corning Co., Ltd. are mixed in equal amounts) to a thickness of about 10 μm. It was applied almost evenly so as to be about the same.

Then, a fluororesin tube 1f was put around it. The fluororesin tube 1f is molded into Φ29, thickness 20 μm, and length 400 mm by an extrusion molding method using fluororesin pellet A (trade name: Teflon (registered trademark) PFA959HPPlus; manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) as a raw material. It was done. The fluororesin pellet A is made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). Its composition consists of a copolymer containing 4.2 mol% of perfluoroethyl vinyl ether (PEVE) as perfluoroalkyl vinyl ether (PAVE). The polymerization ratio of PAVE can be measured by the method described later.

After that, by uniformly handling the surface of the belt from above the fluororesin tube 1f, the excess adhesive 1e can be handled from between the silicone rubber elastic layer 1d and the fluororesin tube 1f so that the adhesive layer 1e becomes sufficiently thin. I put it out. Then, the adhesive 1e was cured by heating in an electric furnace set at 200 ° C. for 5 minutes, and the fluororesin tube 1f was adhesively fixed on the silicone rubber elastic layer 1d. After that, as an annealing treatment, the orientation of the fluororesin tube 1f was relaxed by heating in an electric furnace set at 320 ° C. for 5 minutes. Then, both ends of the endless belt were cut to obtain a fixing belt having a width of 343 mm. The arithmetic average roughness Ra of the surface of this fixing belt was confirmed by the surface roughness measurement described later.

Further, this fixing belt was mounted on an electrophotographic image forming apparatus (manufactured by Canon Inc., trade name: imageRUNNER-ADVANCE C5051), and a melting unevenness evaluation test, a fixing property evaluation test, a gloss evaluation test, and a durability test described later were performed. .. Then, the fixing belt was taken out, only the surface layer was isolated from the fixing belt, and the molecular orientation was confirmed by the molecular orientation measurement described later. In isolating the surface layer, the fluororesin tube 1f was peeled off from the fixing belt with the elastic layer 1d and the adhesive layer 1e still attached so as not to give stress as much as possible, and immersed in a 1-bromopropane solution. The elastic layer 1d and the adhesive layer 1e were dissolved and isolated.

The various results are shown in Table 1. The image forming apparatus has the configuration shown in FIG. 4, and the fixing apparatus thereof has the configuration shown in FIG.

[Example 2]
In the surface layer annealing treatment step of Example 1, the same conditions as in Example 1 except that the orientation of the fluororesin tube 1f was relaxed by heating for 1 minute in an electric furnace set to 320 ° C. as the heating condition. The fixing belt was manufactured in. The evaluation results of this fixing belt are also shown in Table 1.

[Example 3]
As the fluororesin pellet to be used, the copolymer weight containing 1.4 mol% of perfluoropropyl vinyl ether (PPVE) as perfluoroalkyl vinyl ether (PAVE) in the tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). Fluororesin pellet B (trade name: Teflon PFA451HP-J; manufactured by Mitsui Dupont Fluorochemical Co., Ltd.) made of a coalescence was used. The fluororesin pellet B was extruded to form a fluororesin tube 1f having a length of 400 mm, an inner diameter of 29 mm, and a thickness of 20 μm. A fixing belt was produced under the same conditions as in Example 1 except that the fluororesin tube 1f was used. The evaluation results of this fixing belt are also shown in Table 1.

[Example 4]
The fluororesin pellet D, which is the raw material of the release layer, is continuously fed with TFE as a main component and PEV as a comonomer by an aqueous emulsion polymerization method disclosed in Japanese Patent Application Laid-Open No. 2004-161921. , Manufactured by a method of stirring the liquid during polymerization. A fluororesin tube 1f having a length of 400 mm, an inner diameter of 29 mm, and a thickness of 20 μm was formed by extrusion molding. The fluororesin pellet D is made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). As a structure, that perfluoroalkyl vinyl ether (PAVE) as perfluoroethyl vinyl ether (PEVE) are contained 5.8 mol% in the copolymer were confirmed by measurement of ^{19 F} nuclei in nuclear magnetic resonance apparatus.

Using this fluororesin pellet D, a fluororesin tube 1f having a length of 400 mm, an inner diameter of 29 mm, and a thickness of 20 μm was molded by extrusion molding. A fixing belt was produced under the same conditions as in Example 1 except that the fluororesin tube 1f was used. The evaluation results of this fixing belt are also shown in Table 1.

[Example 5]
In the step of forming the elastic layer 1d of Example 1, alumina having an average sphericity of 0.8 and an average particle size of 9.8 μm was used as a functional filler to be blended in the stock solution of the addition-curable silicone rubber. A fixing belt was produced under the same conditions as in Example 1 except that the silicone rubber elastic layer was formed using the undiluted solution. The evaluation results of this fixing belt are also shown in Table 1.

[Example 6]
In the step of forming the elastic layer 1d of Example 1, metallic silicon having an average sphericity of 0.7 and an average particle size of 8.0 μm was used as a functional filler to be blended in the stock solution of the addition-curable silicone rubber. After applying the undiluted solution to the cylindrical substrate and firing it, the endless belt formed up to the silicone rubber elastic layer 1d is rotated in the circumferential direction at a moving speed of 20 mm / sec, and the # 2000 lapping film is brought into contact with it. The smoothing process was carried out in. A fixing belt was produced under the same conditions as in Example 1 except for the above. The evaluation results of this fixing belt are also shown in Table 1.

[Comparative Example 1]
After the fluororesin mold release layer 1f was coated on the endless belt in Example 1, the surface layer annealing treatment step was not performed. A fixing belt was produced under the same conditions as in Example 1 except for the above. The evaluation results of this fixing belt are also shown in Table 1.

[Comparative Example 2]
In the step of forming the elastic layer 1d of Example 1, alumina having an average sphericity of 0.9 and an average particle size of 16.1 μm was used as a functional filler to be blended in the stock solution of the addition-curable silicone rubber. A fixing belt was produced under the same conditions as in Example 1 except that the silicone rubber elastic layer 1d was molded using the undiluted solution. The evaluation results of this fixing belt are also shown in Table 1.

[Comparative Example 3]
No surface smoothing treatment was performed in Example 6. A fixing belt was produced under the same conditions as in Example 6 except for the above. The evaluation results of this fixing belt are also shown in Table 1.

≪Average sphericity≫
When the major axis of the target particle is A and the minor axis is B, it is expressed by the ratio (B / A), and the measurement is performed by taking an optical microscope or electron micrograph of the target particle. This is done by measuring the diameter of the photographed particles. 50 arbitrary particles were counted and calculated from the average value.

≪Average particle size≫
The average particle size shall be determined by a flow type particle image analyzer (trade name: FPIA-3000; manufactured by Sysmex Corporation). Specifically, after crushing the filler in a mortar or the like so that the filler becomes primary particles, this is dispersed in water to prepare a sample solution. This sample liquid is charged into the flow-type particle image analyzer, introduced into an imaging cell in the apparatus, passed through, and the inorganic filler is photographed as a still image. The diameter of a circle (hereinafter, also referred to as “equal area circle”) having an area equal to that of the particle image projected on the plane (hereinafter, also referred to as “particle projection image”) is defined as the diameter of the filler applied to the particle image. Then, the equal area circles of 1000 fillers are obtained, and the arithmetic average value thereof is used as the average particle size of the fillers.

<< Measurement of polymerization ratio of perfluoroalkyl vinyl ether (PAVE) >>
The polymerization rate of perfluoroethyl vinyl ether (PAVE) can be measured using a nuclear magnetic resonance apparatus. The polymerization ratio of perfluoroalkyl vinyl ether (PAVE) in each Example and Comparative Example was measured using a nuclear magnetic resonance apparatus (product name: DSX400 type; manufactured by Bruker Biospin). Specifically ^{, NMR measurements were performed on the 19} F nucleus under the conditions of a MAS frequency of 30 kHz and a cumulative total of 256 times in a room temperature environment. From the obtained NMR chart, the ratio of the integrated value of the peak caused by tetrafluoroethylene (TFE) and the integrated value of the peak caused by perfluoroalkyl vinyl ether (PAVE) was obtained, and the polymerization ratio of PAVE was confirmed from the ratio. In Table 1, this value is referred to as the PAVE ratio.

≪Measurement of orientation of fluororesin release layer≫
The degree of orientation of the fluororesin tube 1f isolated from the fixing belt of the example or the comparative example is obtained by calculating the degree of orientation by the wide-angle X-ray diffraction method. Specifically, the orientation sample has an intensity distribution along the Devi ring, and an X-ray diffraction image is used to measure the degree of orientation. Using a fiber sample table, 2θ was fixed at a peak near 18 °, rotated 360 ° (β rotation), the intensity distribution along the Devi ring was measured, and the degree of orientation was determined by the following formula.

H = [(360-ΣW / 360)] × 100 Here, H: degree of orientation and W: degree of half width crystallinity are calculated by the Ruland method from the diffraction pattern obtained by the wide-angle X-ray diffraction measurement reflection method. There is. As the X-ray diffractometer, a rotary anti-cathode type X-ray diffractometer RINT2500 type (X-ray: CuKα) manufactured by Rigaku Co., Ltd. was used.

≪Measurement of surface roughness of the surface of fixing member≫
The arithmetic average roughness Ra of the surface of the fixing member and the endless belt formed up to the elastic layer 1d can be a known method. The arithmetic average roughness Ra in each Example and Comparative Example was measured by a contact type roughness meter (manufactured by Kosaka Seisakusho, trade name: SE-3500). The various conditions in the measurement are as follows.
Cutoff: 0.8 mm, Filter: Gauss measurement length: 8.0 mm, Scanning speed: 0.1 mm / s, Leveling: Straight line (entire area)
≪Melting unevenness evaluation test≫
By observing the molten state of the toner after fixing the toner image formed on the paper, it can be used as an index of the followability of the fixing member to the unevenness of the paper.

A color laser printer equipped with a fixing belt (manufactured by Canon Inc., trade name: imageRUNNER-ADVANCE C5051), in an environment with a temperature of 10 ° C and a relative humidity of 50%, at an input voltage of 100 V, 10 continuous melt unevenness evaluation images. And settle. The paper is A4 size recycled paper (trade name: recycled paper GF-R100; manufactured by Canon Corporation, thickness 92 μm, basis weight 66 g / m ² , used paper mixing ratio 70%, Beck smoothness 23 seconds (JIS P8119 compliant). Measured by the method)) is used. The melting unevenness evaluation image is an image in which a patch image of 10 mm × 10 mm formed with cyan toner and magenta toner at 100% concentration is arranged near the center of the paper surface.

As a guideline for uneven melting, the toner is melted and mixed when sufficient heat and pressure are applied to the image portion where the two colors are formed. In particular, when heat is applied but pressure is not applied to the concave portions of the paper unevenness, the grain boundaries of the toner remain after fixing, so that uneven melting occurs in a state where the colors are not sufficiently mixed. When the fixing member cannot sufficiently follow the unevenness, pressure is applied to the convex portion to mix colors, but the color mixing is insufficient in the concave portion. Therefore, the determination of the followability to the unevenness was confirmed by observing the molten state in the image forming area.

Evaluation of melting unevenness After printing 10 images in succession, the 10th sample was sampled and the image forming portion was observed with an optical microscope to evaluate the melting unevenness. The evaluation criteria are as follows (see "Melting unevenness" in Table 1).
Evaluation rank A: A state in which the toner grain boundaries are almost invisible even in the concave portions of the paper fibers, and the convex portions of the concave portions are mixed in color.
B: A state in which some toner grain boundaries are observed in the concave portions of the paper fibers, but the convex portions of the concave portions are generally mixed in color.
C: A state in which only the convex portions of the paper fibers are mixed and many toner grain boundaries are observed in the concave portions.

≪Fixability evaluation test≫
The rubbing test is a method for evaluating how firmly the toner is fixed to the paper, and is an index of the high heat supply capacity from the fixing member to the toner. The smaller the thermal resistance value, the better the fixing property. Also tends to improve.

With a color laser printer equipped with the fixing belt, 50 fixingability evaluation images are continuously fixed at an input voltage of 100 V in an environment of a temperature of 10 ° C. and a relative humidity of 50%. Use the same paper as that used for the melting unevenness evaluation test. The fixability evaluation image is an image in which nine 5 mm × 5 mm patch images in which a halftone of a 2 × 2 dot checker flag pattern is composed of a single color of black toner are arranged in nine places on a paper surface.

After printing 50 sheets of the fixability evaluation image in succession, a predetermined number (1,10,20,50th) of samples are extracted from the 50 sheets. A weight of a predetermined weight (200 g) is placed on the image forming surface of the sample via Sylbon paper (trade name: Dasper K-3; manufactured by Ozu Corporation). The weight on the Sylbon paper is rubbed back and forth on the image forming surface 5 times, and the reflection density of the image is measured before and after the rubbing. A denitometer (trade name: RD918; manufactured by Gretag Macbeth) was used for measuring the reflection density.
The rate of decrease in concentration is
(Concentration before rubbing-Concentration after rubbing) / Concentration before rubbing x 100 (%)
Calculated as.

The density reduction rate is 0% when the fixing property is the best, that is, when the evaluation image is not missing at all. On the contrary, when the fixing property is the worst, that is, when all the evaluation images are missing, it becomes 100%. The larger the value of the concentration decrease rate, the worse the fixing property.

As a guideline for the numerical value of toner fixability, when the concentration decrease rate is 30% or more in an environment of a temperature of 10 ° C. and a relative humidity of 50%, the toner image may be missing from the paper under a normal use environment. When the density reduction rate is 20% or more and less than 30%, no problem occurs under normal use environment, but if the image surface is strongly bent, the toner image may be missing from the paper. When the density reduction rate is 10% or more and less than 20%, no problem occurs under normal use environment, but the density of the toner image may decrease when the image surface is strongly rubbed. When the concentration decrease rate is less than 10%, problems such as concentration decrease do not occur under normal use environment.

Therefore, in the determination of the present fixability evaluation, the density reduction rate of the images at 9 places on the paper was obtained, and the worst value among them was adopted and evaluated according to the following criteria. Then, in the item of "fixation" in Table 1, the evaluation ranks are described for each Example and each Comparative Example.
Evaluation rank A: Concentration reduction rate is less than 10%. → It is well established.
B: The rate of decrease in concentration is 10% or more and less than 20%. → Generally well established.
C: Concentration reduction rate is 20% or more. → Insufficient fixation.

≪Gloss evaluation test≫
A solid black image was fixed with a color laser printer (manufactured by Canon Inc., trade name: imageRUNNER-ADVANCE C5051) equipped with a fixing belt. The paper is A4 size recycled paper (trade name: recycled paper GF-R100; manufactured by Canon Corporation, thickness 92 μm, basis weight 66 g / m ² , used paper mixing ratio 70%, Beck smoothness 23 seconds (JIS P8119 compliant). Measured by the method)) was used. The 60 ° gloss of the output image was measured with a gloss meter (Handy type gloss meter PG-1M manufactured by Nippon Denshoku Kogyo Co., Ltd.), and the average value was evaluated according to the following criteria. Then, in the item of "gross" in Table 1, the evaluation ranks are described for each Example and each Comparative Example.
Evaluation rank A: Gross is 10 or more. → High gloss and good image.
B: Gross is 8 or more and less than 10. → It is a good image with high gloss.
C: Gross is less than 8. → Low gloss.

≪Durability test≫
The fixing belt 1 of the example or the comparative example was incorporated into the fixing device of "iR ADVANCE C5051" which is a full color copier manufactured by Canon, and the pressing force was 313.6N (32kgf), the fixing nip was 8 mm × 230 mm, the fixing temperature was 180 ° C, and the process speed. A durability test of 500,000 sheets was carried out at a setting of 246 mm / sec.

As can be seen from Table 1, good results were obtained in all of the melt unevenness, fixability, gloss, and durability with respect to Examples 1 to 6.
(Melting unevenness, fixability, gloss; evaluation ranks A to B, durability; no cracks in 500,000 sheets)
On the other hand, with respect to Comparative Examples 1 to 3, poor results were obtained in any one of melting unevenness, fixability, gloss, durability, or a plurality of items.
(Melting unevenness, fixability, gloss; evaluation rank C, durability; cracks occur in less than 500,000 sheets)

1 Fixing member (fixing belt), 1a inner sliding layer, 1b cylindrical base material,
1c primer layer, 1d silicone rubber elastic layer, 1e adhesive layer,
1f Fluororesin mold release layer (fluororesin tube), 100 fixing device,
101 photosensitive drum, 102 charging device, 103 laser beam, 104 developing device,
105 Intermediate Transfer Drum, 106 Transfer Roller, 107 Toner Cleaner,
108 toner cleaner, 109 deflection mirror, 110 laser optics,
T1 primary transfer unit, T2 secondary transfer unit, 1 fixing member (fixing belt),
2 Pressing member (fixing heater), 3 Thermistor, 4 Film guide and heater holder,
5 Fixing belt stay, 6 Pressurizing member (pressurizing roller), 7 Entrance guide,
8 Fixing paper ejection roller, 9 A / D converter, 10 Control circuit unit (CPU),
11 heater drive circuit section, 12 motor drive circuit section, 13 device frame,
14 Fixing nip part, t Unfixed toner image, P Recording medium

Claims (1)

A method for manufacturing a fixing member having at least a base layer, an elastic layer containing a filler, a fluororesin release layer, and an adhesive layer for adhering the elastic layer and the fluororesin release layer.
A step of forming the elastic layer having an average particle size of the total filler of 10 μm or less and an average sphericity of the filler of 0.8 or more on the base layer.
A step of extruding a fluororesin of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer having a polymerization ratio of perfluoroalkyl vinyl ether of 3.0 mol% or more and 5.8 mol% or less to form a tubular molded body.
Wherein via the adhesive layer to the elastic layer covering the tubular shaped body, and a step of adhering by heat fusion heat to the tubular shaped body above the melting point of the fluororesin,
The fluororesin release layer has an orientation degree of 35% or less and an arithmetic average roughness Ra of the surface of 0.05 μm or less.
Method for manufacturing a fixing member, characterized in that.

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