JP2024063754A - Fixing rotor, fixing device and electrophotographic image forming apparatus - Google Patents

Abstract

[Problem] A fixing rotor having high conductivity and excellent durability. [Solution] The fixing rotor comprises a substrate containing a resin, a conductive layer on the substrate, and a resin layer on the surface of the conductive layer opposite to the side facing the substrate, the conductive layer extending in the circumferential direction of the outer peripheral surface of the substrate, the conductive layer containing silver, the conductive layer having through holes in the thickness direction, and at least a portion of the through holes is filled with a resin constituting at least a portion of the resin layer. [Selected Figure] Figure 1

Description

This disclosure relates to a fixing rotor and fixing device used in a fixing device of an electrophotographic image forming apparatus such as an electrophotographic copying machine or printer, and to an electrophotographic image forming apparatus.

The fixing device installed in electrophotographic image forming devices such as electrophotographic copiers and printers generally heats the recording material carrying an unfixed toner image while conveying it through a nip formed by a heated fixing rotor and a pressure roller in contact with it, fixing the toner image to the recording material.

An electromagnetic induction heating type fixing device has been developed and put to practical use, which has a conductive layer on a fixing rotor and can directly heat the conductive layer. The advantage of the electromagnetic induction heating type fixing device is that it requires a short warm-up time.
As a fixing member used in such a fixing device, Patent Document 1 discloses a fixing member including a base layer containing resin, an electromagnetic induction metal layer containing copper provided on the outer peripheral surface of the base layer, a metal protective layer containing nickel provided in contact with the electromagnetic induction metal layer, and an elastic layer provided on the outer peripheral surface of the metal protective layer.

JP 2021-051136 A

At least one aspect of the present disclosure is directed to providing a fixing rotor having a conductive layer containing silver, in which the conductive layer has high adhesion to a substrate and excellent durability. At least one aspect of the present disclosure is directed to providing a fixing device that contributes to the stable provision of high-quality electrophotographic images. Furthermore, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images.

According to at least one aspect of the present disclosure, there is provided a fixing rotating body, comprising:
The fixing rotor is
A substrate including a resin;
a conductive layer on the substrate;
a resin layer on a surface of the conductive layer opposite to a surface facing the substrate,
the conductive layer extends in a circumferential direction on an outer circumferential surface of the base material,
the conductive layer comprises silver;
the conductive layer has through holes in a thickness direction,
a resin constituting at least a part of the resin layer penetrates at least a part of the through-hole;
A fixing wheel is provided.

According to at least one aspect of the present disclosure,
The fixing rotor;
The fixing device includes an induction heating device that generates heat by induction heating the fixing rotatable body.

Further, in accordance with at least one aspect of the present disclosure, there is provided an electrophotographic image forming apparatus, comprising:
The electrophotographic image forming apparatus comprises:
an image carrier that carries a toner image;
a transfer device for transferring the toner image onto a recording material;
a fixing device for fixing the transferred toner image onto the recording material;
Equipped with
An electrophotographic imaging apparatus is provided, wherein the fixing device is the fixing device described above.

According to at least one aspect of the present disclosure, a fixing rotor having excellent durability and a conductive layer containing silver, which has high adhesion to a substrate, can be obtained. Furthermore, according to at least one aspect of the present disclosure, a fixing device that contributes to the stable provision of high-quality electrophotographic images can be obtained. Furthermore, according to at least one aspect of the present disclosure, an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images can be obtained.

Schematic diagram showing the form of a conductive layer Schematic diagram of an electrophotographic image forming apparatus according to an embodiment. FIG. 1 is a schematic diagram illustrating a cross-sectional configuration of a fixing device according to an embodiment. FIG. 1 is a schematic diagram illustrating a cross-sectional configuration of a fixing device according to an embodiment. Schematic diagram of a magnetic core and an excitation coil of a fixing device according to an embodiment. FIG. 1 is a diagram showing a magnetic field formed when a current is passed through an excitation coil according to an embodiment. Cross-sectional view of a fixing rotatable body according to an embodiment. FIG. 1 is a schematic diagram showing a mechanism for forming pores penetrating in a thickness direction in a conductive layer of a fixing rotatable member according to an embodiment; Cross-sectional images of the substrate, conductive layer, and resin layer of Example 4 (photos substituting drawings)

In this 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 upper and lower 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 combined in any way. In addition, in this disclosure, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

In recent years, printers have become faster, and there is a demand for further improvement in the durability of the conductive layer. When the electromagnetic induction layer contains copper, copper is easily oxidized, so as described in Patent Document 1, it is necessary to protect the copper from oxidation by covering the electromagnetic induction layer with a metal layer such as nickel. Therefore, the present inventors have been considering the use of silver, which is relatively resistant to oxidation and has high conductivity, as a constituent material of the electromagnetic induction layer. In the process, an electromagnetic induction layer (heat generation layer) made of silver was formed on a substrate by silver plating, but the adhesion of the silver plating to the substrate was not necessarily sufficient, and there was still room for improvement in terms of further improving the durability of the fixing member.

The fixing rotor is repeatedly distorted in the nip area under heating, and is required to have long-term durability. One of the destruction modes that affects durability is peeling between layers. This occurs because of the difference in stress applied to the base material made of resin, the conductive layer made of silver, and the resin layer formed on the conductive layer, causing peeling between the base material and the conductive layer, and between the conductive layer and the resin layer. When such defects occur, cracks etc. occur in the conductive layer from there, compromising conductivity.
As a result of investigations, the present inventors have found that by providing the conductive layer with fine pores penetrating in the thickness direction as shown in FIG. 1 and allowing the resin protective layer to penetrate into these through-holes, the substrate, conductive layer, and resin layer are integrated and firmly bonded to each other, thereby suppressing the occurrence of peeling and improving durability.

A fixing rotating member having a conductive layer, and a fixing device and an electrophotographic image forming apparatus using the same will be described in detail below with reference to specific configurations.
However, the dimensions, materials, shapes, and relative positions of the components described in this embodiment are to be changed as appropriate depending on the configuration of the member to which the disclosure is applied and various conditions. In other words, the scope of this disclosure is not intended to be limited to the following embodiment. In the following description, components having the same function are given the same numbers in the drawings, and their description may be omitted.

(Electrophotographic image forming apparatus)
An electrophotographic image forming apparatus (hereinafter also simply referred to as an "image forming apparatus") includes an image carrier that carries a toner image, a transfer device that transfers the toner image onto a recording material, and a fixing device that fixes the transferred toner image onto the recording material.
2 is a cross-sectional view showing the overall configuration of a color laser beam printer (hereinafter, printer) 1 as an example of an image forming apparatus equipped with a fixing device (image heating device) 15 according to the embodiment. A cassette 2 is stored in the lower part of the printer 1 so that it can be pulled out. The cassette 2 stores and stacks sheets P as recording materials. The sheets P in the cassette 2 are separated one by one by a separation roller 3 and fed to a registration roller 4.
In addition, as the recording material, sheet P, a variety of sheets of different sizes and materials can be used, including paper such as ordinary paper and cardboard, sheet materials with surface treatments such as plastic film, cloth, and coated paper, and sheet materials of special shapes such as envelopes and index paper.

The printer 1 is equipped with an image forming section 5 as an image forming means, in which image forming stations 5Y, 5M, 5C, and 5K corresponding to the colors yellow, magenta, cyan, and black are arranged in a horizontal row. The image forming station 5Y is equipped with a photosensitive drum 6Y, which is an image carrier (electrophotographic photosensitive member) that carries a toner image, and a charging roller 7Y, which serves as a charging means for uniformly charging the surface of the photosensitive drum 6Y.

Furthermore, a scanner unit 8 is disposed below the image forming section 5. The scanner unit 8 irradiates a laser beam that is on/off modulated in response to a digital image signal generated by an image processing means based on image information input from an external device such as a computer (not shown), to form an electrostatic latent image on the photosensitive drum 6Y. Furthermore, the image forming station 5Y includes a developing roller 9Y as a developing means that attaches toner to the electrostatic latent image on the photosensitive drum 6Y to develop it into a toner image, and a primary transfer section 11Y that transfers the toner image on the photosensitive drum 6Y to the intermediate transfer belt 10.

Toner images formed by the same process at the other image forming stations 5M, 5C, and 5K are superimposed and transferred onto the toner image on the intermediate transfer belt 10 transferred by the primary transfer unit 11Y. As a result, a full-color toner image is formed on the intermediate transfer belt 10. This full-color toner image is transferred onto the sheet P by the secondary transfer unit 12 as a transfer means. The primary transfer unit 11Y and the secondary transfer unit 12 are examples of fixing devices that fix the transferred toner images onto the recording material.
Thereafter, the toner image transferred onto the sheet P (on the recording material) passes through a fixing device 15 and is fixed as a fixed image. The sheet P then passes through a discharge conveyance section 13 and is discharged and stacked on a stacking section 14.

The image forming unit 5 is an example of an image forming means.
Although 1Y and the secondary transfer unit 12 are exemplified, the fixing device may be, for example, a fixing device of a direct transfer type that directly transfers a toner image from an image carrier to a sheet P. In addition, the image forming apparatus may be configured as a monochrome type that uses toner of only one color.

(Fixing device)
The fixing device 15 of this embodiment is an induction heating type fixing device (image heating device) that heats a fixing rotor by electromagnetic induction. Fig. 3 shows a cross-sectional configuration of the fixing device 15, and Fig. 4 is a perspective view of the fixing device 15. Note that the housing of the fixing device 15 and the like are omitted in Figs. 3 and 4. In the following description, the longitudinal direction X1 of the members that constitute the fixing device 15 is a direction perpendicular to the conveying direction of the recording material and the thickness direction of the recording material.

The fixing device 15 includes a fixing rotor 20, a film guide 25, a pressure roller 21, a pressure stay 22, a magnetic core 26, an excitation coil 27 (FIG. 5), a thermistor 40, and a current sensor 30. The fixing device 15 heats the recording material on which an image has been formed, and fixes the image to the recording material. The fixing rotor 20 is the rotor of this embodiment, and the pressure roller 21 is the opposing member of this embodiment. The excitation coil 27 also functions as a magnetic field generating means of this embodiment. The fixing rotor will be described in detail later.

The fixing rotor 20 has a conductive layer 20b on a base material, which serves as a heat generating layer. The conductive layer 20b can generate heat, for example, by induced current. The conductive layer (heat generating layer) 20b is formed in a ring shape, electrically connected to each other in the circumferential direction, and is electrically divided in the longitudinal direction X1 (the direction of the rotation axis of the fixing rotor 20), forming a heat generating pattern of heat generating rings 201 ( FIG. 4 ) arranged in the longitudinal direction.
In other words, the conductive layer 20b is divided into a plurality of annular regions that are each connected in the circumferential direction of the fixing rotor 20 and are not electrically connected to each other in the direction of the rotation axis of the fixing rotor 20. Each of the heat generating rings 201, which is a component of the heat generating pattern, is formed with a uniform width in the longitudinal direction X1.

The pressure roller 21, which serves as an opposing body (pressure member) facing the fixing rotor 20, comprises a core 21a and an elastic layer 21b that is molded and coated concentrically around the core into a roller shape, with a release layer 21c provided on the surface. The elastic layer 21b is preferably made of a material with good heat resistance, such as silicone rubber, fluororubber, or fluorosilicone rubber. Both ends of the core 21a in the longitudinal direction are held rotatably between the chassis side metal plates (not shown) of the device via conductive bearings.

In addition, as shown in FIG. 4, pressure springs 24a, 24b are respectively provided between both longitudinal ends of the pressure stay 22 and spring receiving members 23a, 23b on the device chassis side, thereby applying a downward force to the pressure stay 22.
In the fixing device 15 of this embodiment, a total pressure of about 100 N to 300 N (about 10 kgf to about 30 kgf) is applied. As a result, the lower surface of the film guide 25 made of heat-resistant resin such as PPS and the upper surface of the pressure roller 21 are in pressure contact with the fixing rotor 20, which is a cylindrical rotor, sandwiched between them, forming a fixing nip portion N of a predetermined width.
The film guide 25 functions as a nip portion forming member that, together with the pressure roller 21, forms a nip portion that sandwiches and conveys the recording material carrying the toner image via the fixing rotor 20. Here, PPS is polyphenylene sulfide.

The pressure roller 21 is driven to rotate in a clockwise direction by a driving means (not shown), and a counterclockwise rotational force acts on the fixing rotor 20 due to friction with the outer surface of the fixing rotor 20. As a result, the fixing rotor 20 rotates while sliding against the film guide 25.

5 is a schematic diagram of the magnetic core 26 and the excitation coil 27 in FIG. 3, and the fixing rotor 20 is indicated by a dashed line to explain the positional relationship with the fixing rotor 20. An induction heating device in an induction heating fixing device that heats the fixing rotor 20 by electromagnetic induction may include the magnetic core 26 and the excitation coil 27.
The exciting coil 27 is disposed inside the fixing rotor 20. The exciting coil 27 has a helical portion whose helical axis is substantially parallel to the direction along the rotation axis of the fixing rotor 20, and forms an alternating magnetic field that causes the conductive layer 20b to generate heat through electromagnetic induction. "Substantially parallel" does not mean that the two axes are completely parallel, but rather that a slight misalignment is permitted to the extent that the conductive layer can generate heat through electromagnetic induction.
The magnetic core 26 is disposed in the spiral portion, extends in the direction of the rotation axis of the fixing rotor 20, and does not form a loop outside the fixing rotor 20. The magnetic core 26 induces magnetic field lines of the alternating magnetic field.

In FIG. 5, the magnetic core 26 is inserted into the hollow portion of the fixing rotor 20, which is a cylindrical rotor. The excitation coil 27 is wound in a spiral shape around the outer circumference of the magnetic core 26 and extends in the longitudinal direction of the fixing rotor 20. The magnetic core 26 is cylindrical, and is fixed by a fixing means (not shown) so that it is located approximately in the center of the fixing rotor 20 in a cross section viewed in the longitudinal direction (see FIG. 3).

The magnetic core 26 provided inside the excitation coil 27 has a role of guiding the magnetic field lines (magnetic flux) of the alternating magnetic field generated by the excitation coil 27 inward from the conductive layer 20b of the fixing rotor 20, and forming a path (magnetic path) of the magnetic field lines. The material of the magnetic core 26 is a ferromagnetic material. The material of the magnetic core 26, which is a ferromagnetic material, is preferably a material with small hysteresis loss and high relative permeability, for example, at least one high-permeability soft magnetic material selected from the group consisting of sintered ferrite, ferrite resin, etc.
Preferably, 70% or more of the magnetic flux emitted from one longitudinal end of the magnetic core 26 in the rotation axis direction passes outside the conductive layer 20b and returns to the other longitudinal end of the magnetic core 26.

The cross-sectional shape of the magnetic core 26 does not have to be circular as long as it can be stored in the hollow portion of the fixing rotor 20, but a shape that allows the cross-sectional area to be as large as possible is preferable. In this embodiment, the diameter of the magnetic core 26 is 10 mm, and the longitudinal length is 280 mm.

The excitation coil 27 is formed by winding 20 turns of copper wire (single conductor) with a diameter of 1 to 2 mm coated with heat-resistant polyamideimide in a spiral shape around the magnetic core 26. The excitation coil 27 is wound around the magnetic core 26 in a direction that intersects with the direction of the rotation axis of the fixing rotor 20. Therefore, when a high-frequency alternating current is passed through this excitation coil 27, an alternating magnetic field is generated in a direction parallel to the direction of the rotation axis, and an induced current (circulating current) flows in each heating ring 201 of the conductive layer 20b of the fixing rotor 20 according to the principle described below, generating heat.

As shown in Figures 3 and 4, the thermistor 40, which serves as a temperature detection means for detecting the temperature of the fixing rotor 20, is composed of a spring plate 40a and a thermistor element 40b. The spring plate 40a is a support member having spring elasticity that extends toward the inner surface of the fixing rotor 20. The thermistor element 40b, which serves as a temperature detection element, is installed at the tip of the spring plate 40a. The surface of the thermistor element 40b is covered with a 50 μm thick polyimide tape to ensure electrical insulation.

The thermistor 40 is fixed to the film guide 25 at a position approximately at the center of the fixing rotor 20 in the longitudinal direction. The thermistor element 40b is pressed against the inner surface of the fixing rotor 20 by the spring elasticity of the spring plate 40a and is maintained in contact with the inner surface of the fixing rotor 20. The thermistor 40 may be disposed on the outer periphery of the fixing rotor 20.

The current sensor 30, which constitutes the continuity monitoring device that monitors the circumferential continuity of the conductive layer 20b, is located at the same position as the thermistor 40 in the longitudinal direction of the fixing device 15. In other words, what is monitored by the current sensor 30 is the continuity state of the heating ring 201 that is in contact with the thermistor element 40b among the multiple heating rings 201 that constitute the heating pattern of the fixing rotor 20.

(Heating principle)
The heating principle of the fixing rotor 20 in the fixing device 15 using the induction heating method will be described. Fig. 6 is a conceptual diagram showing the moment when the current in the exciting coil 27 increases in the direction of the arrow I0. The exciting coil 27 is inserted into the fixing rotor 20, and functions as a magnetic field generating means that generates an induced current I in the circumferential direction of the fixing rotor 20 by passing an alternating current through it to form an alternating magnetic field in the direction of the rotation axis of the fixing rotor 20.
The magnetic core 26 also functions as a member that induces magnetic field lines B (dotted lines in the figure) generated by the excitation coil 27 and forms a magnetic path. In a typical induction heating method, magnetic field lines penetrate a conductive layer to generate eddy currents, whereas in this embodiment, the magnetic field lines B loop on the outside of the fixing rotor. That is, the conductive layer 20b is mainly heated by the induced current induced by the magnetic field lines that leave one longitudinal end of the magnetic core 26, pass outside the conductive layer 20b, and return to the other longitudinal end of the magnetic core 26. This allows efficient heat generation even when the conductive layer is thin, for example, 4 μm or less.

When an alternating magnetic field is generated by the excitation coil 27, an induced current I flows in each heating ring 201 of the conductive layer 20b of the fixing rotor 20 according to Faraday's law. Faraday's law states that "when the magnetic field in a circuit is changed, an induced electromotive force is generated that tries to cause a current to flow in the circuit, and the induced electromotive force is proportional to the time change in the magnetic flux that perpendicularly penetrates the circuit."

Ｖ：誘導起電力
Ｎ：コイル巻き数
ΔΦ／Δｔ：微小時間Δｔでの回路（発熱リング２０１ｃ）を垂直に貫く磁束の変化 Consider the induced current I that flows through heat-generating ring 201c located at the center in the longitudinal direction of magnetic core 26 shown in Fig. 6 when a high-frequency alternating current is passed through excitation coil 27. When a high-frequency alternating current is passed, an alternating magnetic field is formed inside magnetic core 26. In this case, the induced electromotive force acting on heat-generating ring 201c is proportional to the time change in magnetic flux that perpendicularly penetrates the inside of heat-generating ring 201c, according to the following equation 1.

V: Induced electromotive force N: Number of coil turns ΔΦ/Δt: Change in magnetic flux perpendicularly penetrating the circuit (heat generating ring 201c) in a short time Δt

This induced electromotive force V causes an induced current I, which is a circular current that circulates around the heating ring 201c, to flow, causing the heating ring 201c to heat up due to Joule heat generated by the induced current I. However, if the heating ring 201c is broken, the induced current I does not flow, and the heating ring 201c does not generate heat.

(1) Outline of Configuration of Fixing Rotor The fixing rotor of this embodiment will be described in detail with reference to the drawings.
The fixing rotatable member according to one aspect of the present disclosure may be, for example, a rotatable member having an endless belt shape.
Fig. 7 is a cross-sectional view of the fixing rotor in the circumferential direction. As shown in Fig. 7, the fixing rotor has a base material 20a, a conductive layer 20b on the outer surface of the base material 20a, and a resin layer 20e on the outer surface of the conductive layer. If necessary, an elastic layer 20c and a surface layer (release layer) 20d may be provided on the resin layer 20e, and an adhesive layer 20f may be provided between the elastic layer 20c and the surface layer 20d.

(2) Substrate The material of the substrate 20a is not particularly limited as long as it is a layer containing at least a resin. That is, the substrate 20a contains a resin. When the belt is used in an electromagnetic induction type fixing device, the substrate 20a is preferably a layer that has little change in physical properties and maintains high strength when the conductive layer is heated. For this reason, the substrate 20a preferably contains a heat-resistant resin as a main component, and is preferably made of a heat-resistant resin.

The resin contained in the substrate 20a (preferably the resin constituting the substrate) preferably contains at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), modified polyimide, and modified polyamideimide. More preferably, it is at least one selected from the group consisting of polyimide and polyamideimide. Among these, polyimide is particularly preferable. In this disclosure, the main component means the component contained in the largest amount among the components constituting the target object (here, the substrate).
The modified polyimide and modified polyamideimide include siloxane-modified, carbonate-modified, fluorine-modified, urethane-modified, triazine-modified, and phenol-modified.

A filler may be blended into the base material 20a to improve heat insulation and strength.
The shape of the substrate can be appropriately selected depending on the shape of the fixing rotor, and can be, for example, an endless belt shape, a hollow cylinder shape, a film shape, or various other shapes.

In the case of a fixing belt, the thickness of the base material 20a is, for example, preferably 10 to 100 μm, and more preferably 20 to 60 μm. By setting the thickness of the base material 20a within the above range, it is possible to achieve both high levels of strength and flexibility.
In addition, on the surface of the substrate 20a opposite the side facing the conductive layer 20b, for example, a layer for preventing wear of the inner surface of the fixing belt when the inner surface of the fixing belt comes into contact with other members, or a layer for improving sliding properties with other members may be provided.

In addition, the outer peripheral surface of the substrate 20a may be subjected to a roughening treatment such as blasting, or a modification treatment such as ultraviolet light, plasma, or chemical etching in order to improve adhesion and wettability with the conductive layer 20b.

(3) Conductive Layer The conductive layer 20b is a layer that generates heat when current is applied. In the principle of heat generation by induction heating using an excitation coil, when an alternating current is supplied to an excitation coil arranged near the fixing rotor, a magnetic field is induced, and a current is generated in the conductive layer 20b of the fixing rotor by the magnetic field, and heat is generated by Joule heat.

The material of the conductive layer 20b is preferably silver, which has a low volume resistivity and is resistant to oxidation. The conductive layer 20b contains silver. The conductive layer 20b may contain metals other than silver to an extent that does not impair the effects of the present disclosure. However, the purity of the silver constituting the conductive layer is preferably 90% by mass or more, more preferably 99% by mass or more, and particularly preferably 99.9% by mass or more. There is no particular upper limit. For example, it is 100% by mass or less.

In the fixing rotating member, the material of the conductive layer, specifically, for example, the purity of silver when the conductive layer contains silver, can be analyzed by the following procedure.
Six samples, each 5 mm long, 5 mm wide, and the full thickness of the fixing rotor, are taken from any location of the fixing rotor. The circumferential cross sections of the six samples are exposed using a cross-section polisher (product name: SM09010, manufactured by JEOL Ltd.).

Next, the cross section of the exposed conductive layer is observed with a scanning electron microscope (SEM) (product name: JSM-F100, manufactured by JEOL Ltd.), and the silver crystal particles in the observed image are analyzed by energy dispersive X-ray spectroscopy (EDS). The observation conditions are 20,000x magnification, secondary electron image acquisition mode, and EDS analysis conditions are accelerating voltage 5.0 kV, working distance: 10 mm. The spatial range in which the EDS analysis is performed is specified by area, and adjusted so that only the silver crystal particles in the observed image are selected.
One image is taken for one sample, and EDS analysis is performed at three points within each image. The purity is analyzed at a total of 18 points for six samples, and the arithmetic average value is calculated to determine the purity of the silver that constitutes the conductive layer.

The maximum thickness of the conductive layer 20b is preferably 4 μm or less. By making the maximum thickness of the conductive layer 4 μm or less, the heat capacity of the conductive layer can be sufficiently reduced, and the time until the conductive layer reaches a temperature at which fixing can be performed by electromagnetic induction can be shortened. In addition, by making the maximum thickness of the conductive layer 4 μm or less, the bending resistance of the fixing rotor can be further improved. As shown in FIG. 3, the fixing rotor 20 is rotated while being pressed by the film guide 25 and the pressure roller 21. With each rotation, the fixing rotor 20 is pressurized and deformed at the nip portion N, and is subjected to stress.
Even if the fixing rotor is subjected to such repeated bending over a long period of time, the conductive layer 20b is less likely to be broken by fatigue, by setting the maximum thickness of the conductive layer to 4 μm or less. This is because, when the conductive layer 20b is pressed and deformed to conform to the shape of the curved surface of the film guide 25, the internal stress acting on the conductive layer 20b becomes smaller as the conductive layer 20b is thinner.

The lower limit of the maximum thickness of the conductive layer 20b is not particularly limited, but is preferably 1 μm or more. Therefore, the maximum thickness of the conductive layer 20b is preferably 1 to 4 μm, and more preferably 1 to 3 μm.

The maximum thickness of the conductive layer on the fixing rotor can be measured, for example, by the following method.
Six samples, each 5 mm long, 5 mm wide, and the full thickness of the fixing rotor, are taken from any location of the fixing rotor. The circumferential cross sections of the six samples are exposed using a cross-section polisher (product name: SM09010, manufactured by JEOL Ltd.).
Next, the cross section of the exposed conductive layer was observed with a scanning electron microscope (SEM) (product name: JSM-F100, manufactured by JEOL Ltd.) at an acceleration voltage of 3 kV, a working distance of 2.9 mm, and a magnification of 10,000 times to obtain an image with a width of 13 μm and a height of 10 μm. Parallel lines were drawn between the conductive layer in the obtained image at the location closest to the substrate side and the location closest to the resin layer side on the opposite side, and the distance between the parallel lines was defined as the thickness in the image, and the arithmetic average value of the six samples was defined as the maximum thickness. The parallel lines were drawn based on the surface of the substrate opposite the conductive layer in the observation area.

The conductive layer 20b extends in the circumferential direction of the outer peripheral surface of the base material 20a. The conductive layer 20b may be configured in a predetermined pattern as long as it can generate heat when current is applied. In particular, as shown in FIG. 4, a configuration in which a plurality of conductive layers 20b each having a ring shape in the circumferential direction of the fixing rotor are formed in an electrically divided state in the axial direction of the rotor is preferable. By adopting such a configuration, it is possible to suppress a local temperature rise when a crack occurs in the conductive layer 20b. It is preferable that the width of the ring shape in the axial direction of the rotor is approximately constant.
When the conductive layer is configured in the above-mentioned pattern, the surface area of the conductive layer 20b increases. In this case, if the conductive layer is made of copper, it is more likely to be oxidized. However, when silver is used as the material for the conductive layer, it is possible to prevent the oxidation of the conductive layer caused by the increase in surface area due to the above-mentioned pattern configuration of the conductive layer.

From the viewpoints of manufacturability and heat generation, the width of the ring of the conductive layer 20b is preferably 100 μm or more, and more preferably 200 μm or more. From the viewpoints of uneven heat generation and safety, the width is preferably 500 μm or less, and more preferably 400 μm or less. Examples of the width of the ring include 100 to 500 μm and 200 to 400 μm.

From the viewpoints of manufacturability and heat generation, the spacing between the rings of the conductive layer 20b is preferably 50 μm or more, and more preferably 100 μm or more. From the viewpoint of uneven heat generation, the spacing is preferably 400 μm or less, and more preferably 300 μm or less. Examples of spacing between the rings include 50 to 300 μm and 100 to 300 μm.

The conductive layer 20b has through holes in the thickness direction. The presence of these through holes allows the resin layer described below to penetrate into the through holes and reach the base material 20a. As a result, the base material 20a, the conductive layer 20b, and the resin layer 20e are integrated and firmly adhered to each other, suppressing the occurrence of peeling and improving durability.

There are no particular limitations on the method for forming pores penetrating the conductive layer 20b in the thickness direction. For example, after forming a pattern on the conductive layer 20b by a photolithography process, holes may be formed by chemical etching, or holes may be formed using a laser or focused ion beam. In this disclosure, in particular, pore formation using a silver nanoparticle material will be described.

First, a coating is formed using paint containing silver nanoparticles with a particle size of approximately 10 to 50 nm. This results in a layered structure of particles as shown in Figure 8A. Due to the instability of the surface energy of nanoparticles, the particles fuse together even when fired at a low temperature of approximately 100°C, forming a film with nano-sized pores as shown in Figure 8B. The conductive layer 20b is preferably a sintered body of silver nanoparticles.

The laminate with the silver nanoparticles formed thereon is then baked (sintered) at a high temperature of about 300°C. The baking temperature is preferably 280-450°C, or 300-400°C. When baked, the nanoparticles further coalesce with each other, and the pores also coalesce with each other in an attempt to minimize the surface energy, growing until they penetrate in the thickness direction as shown in Figure 8C.

The pores formed in this way are connected not only in the thickness direction but also in the circumferential and axial directions, and are thought to have a three-dimensional network structure. The resin layer 20e, which will be described later, penetrates into the pores, dramatically increasing the contact area between the conductive layer 20b and the resin layer 20e, and the increased anchor effect is thought to greatly improve the adhesive strength.

(4) Resin Layer The fixing rotor includes a resin layer 20e on the surface of the conductive layer 20b opposite to the surface facing the base material 20a. The resin layer 20e protects the conductive layer 20b and has the functions of preventing oxidation of the conductive layer 20b, ensuring insulation, and improving strength.

The resin constituting at least a part of the resin layer 20e is not particularly limited. The resin used for the resin layer 20e is preferably a resin that, like the resin of the substrate 20a, changes little in physical properties when the conductive layer 20b generates heat and can maintain high strength. For this reason, the resin layer 20e preferably contains a heat-resistant resin as a main component, and is preferably composed of a heat-resistant resin. The heat-resistant resin is, for example, a resin that does not melt or decompose at a temperature of less than 200°C (preferably less than 250°C).

The resin constituting at least a part of the resin layer 20e preferably contains at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), modified polyimide, and modified polyamideimide. More preferably, it is at least one selected from the group consisting of polyimide and polyamideimide. The modification is the same as that described for the substrate 20a.

These imide-based materials can be applied in a liquid form called varnish, so when applied onto the conductive layer 20b, they penetrate into the pores formed in the conductive layer 20b, and can then be turned into a film in that state by baking. By using the same imide-based material as the substrate 20a, it is easier to ensure adhesion when the material penetrates into the pores of the conductive layer 20b and reaches the substrate 20a, and peeling can be further suppressed.

The resin constituting at least a part of the resin layer 20e may penetrate at least a part of the through-hole. In addition, it is preferable that the resin constituting the resin layer 20e that penetrates into the through-hole is in contact with the base material 20a. The degree of penetration is not particularly limited, and it is sufficient that the resin penetrates to an extent that peeling can be suppressed.
For example, when observed with a scanning electron microscope, preferably 50 to 100%, 80 to 100%, or 90 to 100% of the through holes are filled with resin (more preferably in contact with the base material 20a).

The resin layer 20e may contain a thermally conductive filler from the viewpoint of heat transfer. By improving the heat transfer, the heat generated in the conductive layer 20b can be efficiently transferred to the outer surface of the fixing rotor.

The thickness of the resin layer 20e is preferably 10 to 100 μm, more preferably 20 to 60 μm. In addition, from the viewpoint of alleviating the stress applied to the conductive layer 20b when the fixing rotor is bent, it is preferable to appropriately adjust the thickness of the resin layer 20e and the thickness of the substrate 20a according to their materials. Specifically, for example, when the substrate and the resin layer are made of the same material, for example, polyimide, it is preferable to make the thickness of the substrate and the resin layer approximately equal. That is, the ratio of the absolute value of the difference in thickness between the substrate and the resin layer to the thickness of the substrate is preferably 10% or less, particularly 5% or less. In addition, when the substrate is made of polyimide and the resin layer is made of polyamideimide, it is preferable to set the thickness of the resin layer to, for example, 15% or more and 25% or less of the thickness of the substrate. By setting the thickness relationship between the substrate and the resin layer as described above, it is possible to more reliably suppress the occurrence of cracks in the conductive layer 20b when the fixing rotor is bent.

In the fixing rotating member, the materials of the base material 20a and the resin layer 20e can be analyzed by the following procedure.
A sample of 10 mm square is cut out from the fixing rotor, and if an elastic layer or a surface layer is present, it is removed with a razor, a solvent, etc. The material can be confirmed by performing an attenuated total reflection (ATR) measurement on the obtained sample using an infrared spectroscopic analyzer (FT-IR) (for example, product name: Frontier FT IR, manufactured by PerkinElmer).

(5) Elastic Layer The fixing rotor may have an elastic layer 20c on the outer surface of the resin layer 20e. The elastic layer 20c is a layer for imparting flexibility to the fixing rotor in order to secure a fixing nip in the fixing device. When the fixing rotor is used as a heating member that comes into contact with the toner on the paper, the elastic layer 20c also functions as a layer for imparting flexibility so that the surface of the heating member can follow the unevenness of the paper.
The elastic layer 20c includes, for example, rubber as a matrix and particles dispersed in the rubber. More specifically, the elastic layer 20c preferably includes rubber and a thermally conductive filler, and is preferably made of a cured product obtained by curing a composition including at least the raw materials of the rubber (base polymer, crosslinking agent, etc.) and the thermally conductive filler.

From the viewpoint of realizing the functions of the elastic layer 20c described above, the elastic layer 20c is preferably made of a cured silicone rubber containing thermally conductive particles, and more preferably made of a cured addition-curing type silicone rubber composition.
The silicone rubber composition may contain, for example, thermally conductive particles, a base polymer, a crosslinking agent, a catalyst, and, if necessary, additives. Since the silicone rubber composition is often liquid, the thermally conductive filler is easily dispersed therein, and the elasticity of the elastic layer 20c to be produced can be easily adjusted by adjusting the degree of crosslinking according to the type and amount of the thermally conductive filler added.

The matrix has the function of providing elasticity in the elastic layer 20c. From the viewpoint of providing the above-mentioned function of the elastic layer 20c, it is preferable that the matrix contains silicone rubber. Silicone rubber is preferable because it has high heat resistance that allows it to maintain flexibility even in environments where the non-paper passing area is as high as about 240°C. As the silicone rubber, for example, a cured product of an addition-curing liquid silicone rubber composition described below can be used. The elastic layer 20c can be formed by applying and heating the liquid silicone rubber composition by a known method.

The liquid silicone rubber composition generally contains the following components (a) to (d):
Component (a): an organopolysiloxane having an unsaturated aliphatic group;
Component (b): an organopolysiloxane having silicon-bonded active hydrogen;
Component (c): catalyst;
Component (d): Thermally Conductive Filler Each component will now be described.

Component (a)
The organopolysiloxane having an unsaturated aliphatic group is an organopolysiloxane having an unsaturated aliphatic group such as a vinyl group, and examples thereof include those represented by the following formulas (1) and (2).

In formula (1), ^m1 represents an integer of 0 or greater, and ⁿ¹ represents an integer of 3 or greater. In addition, in structural formula (1), each ^R1 independently represents a monovalent unsubstituted or substituted hydrocarbon group that does not contain an unsaturated aliphatic group, provided that at least one of ^R1 represents a methyl group, and each ^R2 independently represents an unsaturated aliphatic group.

In formula (2), ⁿ² represents a positive integer, each ^R3 independently represents a monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group, provided that at least one of ^R3 represents a methyl group, and each ^R4 independently represents an unsaturated aliphatic group.

In formulas (1) and (2), examples of the monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group which can be represented by R ¹ and R ³ include the following groups.
Unsubstituted hydrocarbon alkyl groups (eg, methyl, ethyl, propyl, butyl, pentyl, hexyl).
Aryl groups (eg, phenyl groups).
Substituted hydrocarbon groups and substituted alkyl groups (for example, chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3-cyanopropyl, and 3-methoxypropyl groups).

The organopolysiloxanes represented by formulas (1) and (2) have at least one methyl group directly bonded to the silicon atom forming the chain structure. However, for ease of synthesis and handling, it is preferred that at least 50% of ^R1 and ^R3 are methyl groups, and it is more preferred that all ^R1 and ^R3 are methyl groups.

In addition, examples of unsaturated aliphatic groups that can be represented by ^R2 and ^R4 in formulas (1) and (2) include the following groups. That is, examples of unsaturated aliphatic groups include a vinyl group, an allyl group, a 3-butenyl group, a 4-pentenyl group, and a 5-hexenyl group. Among these groups, it is preferable that both ^R2 and ^R4 are vinyl groups, since they are easy to synthesize and handle at low cost and the crosslinking reaction is easily carried out.

From the viewpoint of moldability, the viscosity of component (a) is preferably 1000 mm ² /s or more and 50000 mm ² /s or less. If it is less than 1000 mm ² /s, it becomes difficult to adjust the hardness required for the elastic layer 20c, and if it is more than 50000 mm ² /s, the viscosity of the composition becomes too high and coating becomes difficult. The viscosity (kinetic viscosity) can be measured using a capillary viscometer, a rotational viscometer, or the like based on JIS Z 8803:2011.

The amount of component (a) is preferably 55% by volume or more from the viewpoint of durability and 65% by volume or less from the viewpoint of heat transfer, based on the liquid silicone rubber composition used to form the elastic layer 20c.

Component (b)
The organopolysiloxane having active silicon-bonded hydrogens functions as a crosslinker which reacts with the unsaturated aliphatic groups of component (a) in the presence of a catalyst to form a cured silicone rubber.
Any organopolysiloxane having a Si-H bond can be used as component (b), and from the viewpoint of reactivity with the unsaturated aliphatic group of component (a), it is particularly preferred to use one having an average of 3 or more hydrogen atoms bonded to silicon atoms per molecule.

Specific examples of component (b) include the linear organopolysiloxane shown by the following formula (3) and the cyclic organopolysiloxane shown by the following formula (4).

In formula (3), ^m2 represents an integer of 0 or more, ⁿ³ represents an integer of 3 or more, and each ^R5 independently represents a monovalent unsubstituted or substituted hydrocarbon group that does not contain an unsaturated aliphatic group.

In formula (4), ^m3 represents an integer of 0 or more, ⁿ⁴ represents an integer of 3 or more, and each ^R6 independently represents a monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group.

Examples of monovalent unsubstituted or substituted hydrocarbon groups not containing unsaturated aliphatic groups that can be represented by ^R5 and ^R6 in formulas (3) and (4) include groups similar to R1 in the above-mentioned structural formula ( ¹ ). Among these, it is preferable that 50% or more of ^R5 and ^R6 are methyl groups, and it is more preferable that all of ^R5 and ^R6 are methyl groups, because synthesis and handling are easy and excellent heat resistance can be easily obtained.

Component (c)
The catalyst used in forming the silicone rubber may be, for example, a hydrosilylation catalyst for promoting the curing reaction. As the hydrosilylation catalyst, for example, a known substance such as a platinum compound or a rhodium compound may be used. The amount of the catalyst to be added may be appropriately set and is not particularly limited.

Component (d)
Examples of the thermally conductive filler include metals, metal compounds, and carbon fibers. Highly thermally conductive fillers are more preferred, and specific examples thereof include the following materials:
Silicon metal (Si), silicon carbide ( _SiC ), silicon nitride ( _Si3N4 ), boron nitride (BN), aluminum nitride ( _AlN ), alumina ( _Al2O3 ), zinc oxide (ZnO), magnesium oxide (MgO), silica ( _SiO2 ), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), vapor grown carbon fiber, PAN (polyacrylonitrile) carbon fiber, pitch based carbon fiber.

These fillers can be used alone or in combination of two or more kinds.
The average particle size of the filler is preferably 1 μm or more and 50 μm or less from the viewpoint of handling and dispersibility. The shape of the filler may be spherical, pulverized, needle-like, plate-like, or whisker-like. In particular, from the viewpoint of dispersibility, the filler is preferably spherical. Furthermore, at least one of a reinforcing filler, a heat-resistant filler, and a coloring filler may be added.

(6) Adhesive Layer The fixing rotating body may have an adhesive layer 20f on the outer surface of the elastic layer 20c for adhering the surface layer 20d described later. The adhesive layer 20f is a layer for adhering the elastic layer 20c and the surface layer 20d. The adhesive used for the adhesive layer 20f can be appropriately selected from known adhesives and is not particularly limited. However, from the viewpoint of ease of handling, it is preferable to use an addition curing type silicone rubber containing a self-adhesive component.
The adhesive may contain, for example, a self-adhesive component, an organopolysiloxane having a plurality of unsaturated aliphatic groups, typically vinyl groups, in the molecular chain, a hydrogen organopolysiloxane, and a platinum compound as a crosslinking catalyst. The adhesive applied to the surface of the elastic layer 20c is cured by an addition reaction to form an adhesive layer 20f that bonds the surface layer 20d to the elastic layer 20c.

Examples of the self-adhesive component include the following:
Silanes having at least one functional group, preferably two or more functional groups, selected from the group consisting of an alkenyl group such as a vinyl group, a (meth)acryloxy group, a hydrosilyl group (SiH group), an epoxy group, an alkoxysilyl group, a carbonyl group, and a phenyl group.
Organosilicon compounds, such as cyclic or linear siloxanes, having 2 to 30 silicon atoms, and preferably 4 to 20 silicon atoms.
- A non-silicon-based (i.e., silicon-free) organic compound that may contain oxygen atoms in the molecule, provided that it contains one to four, preferably one to two, aromatic rings such as phenylene structures having a valence of 1 to 4, preferably divalent to 4, in one molecule, and at least one, preferably two to four, functional groups capable of contributing to a hydrosilylation addition reaction (e.g., alkenyl groups, (meth)acryloxy groups) in one molecule.

The above-mentioned self-adhesive components may be used alone or in combination of two or more. In addition, from the viewpoint of adjusting viscosity and ensuring heat resistance, a filler component may be added to the adhesive within the scope of the present invention. Examples of the filler component include the following.
-Silica, alumina, iron oxide, cerium oxide, cerium hydroxide, carbon black, etc.

The amount of each component contained in the adhesive is not particularly limited and can be set as appropriate. Such addition-curing silicone rubber adhesives are commercially available and can be easily obtained. The thickness of the adhesive layer 20f is preferably 20 μm or less. By setting the thickness of the adhesive layer 20f to 20 μm or less, when the fixing belt according to this embodiment is used as a heating belt in a thermal fixing device, the thermal resistance can be easily set small, and heat from the inner surface can be easily transferred to the recording medium efficiently.

(7) Surface Layer The fixing rotor may have a surface layer 20d. The surface layer 20d preferably contains a fluororesin in order to function as a release layer that prevents toner from adhering to the outer surface of the fixing rotor. For example, the surface layer 20d may be formed by molding a resin such as those exemplified below into a tube shape, or the surface layer 20d may be formed by coating a resin dispersion liquid.
Tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc.
Among the resin materials exemplified above, PFA is particularly preferably used from the viewpoints of moldability and toner releasability.

The thickness of the surface layer 20d is preferably 10 μm or more and 50 μm or less. By keeping the thickness of the surface layer 20d within this range, it is easy to maintain an appropriate surface hardness of the fixing rotor.

As described above, according to one aspect of the present disclosure, a fixing device in which a fixing rotor is disposed is provided. Therefore, it is possible to provide a fixing device in which a fixing rotor that is highly conductive and has excellent durability is disposed.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[Example 1]
A cylindrical stainless steel mold having an outer diameter of 30 mm was subjected to a release treatment on its surface, and a commercially available polyimide precursor solution (U Varnish S, manufactured by Ube Industries, Ltd.) was applied thereto by immersion to form a coating film. The coating film was then dried at 140° C. for 30 minutes to volatilize the solvent in the coating film, and then baked at 200° C. for 30 minutes and 400° C. for 30 minutes to imidize the film, forming a polyimide film having a thickness of 40 μm and a length of 300 mm.
Next, a ring-shaped pattern was formed on the polyimide film by an inkjet method using a silver nanoparticle-containing ink (DNS163, manufactured by Daicel Corporation) so as to have a width of 300 μm and intervals of 200 μm. Then, the pattern was baked at 300° C. for 30 minutes to form a conductive layer 20b having a maximum thickness of 2 μm.

Next, a PAI solution (Viromax HR-16NN, manufactured by Toyobo Co., Ltd.) was applied to the entire surface of the conductive layer 20b by ring coating, and then baked at 200° C. for 30 minutes to form a resin layer 20e having a thickness of 40 μm.
Next, a primer (product name: DY39-051A/B, manufactured by Dow Toray Industries, Inc.) was applied approximately uniformly to the outer peripheral surface of the resin layer 20e so that the dry weight was 20 mg, and after the solvent was dried, a baking process was performed for 30 minutes in an electric furnace set at 160°C.
On this primer, a silicone rubber composition layer having a thickness of 250 μm was formed by ring coating, and the layer was subjected to primary crosslinking at 160° C. for 1 minute, followed by secondary crosslinking at 200° C. for 30 minutes to form an elastic layer 20 c.

The silicone rubber composition used was as follows:
As component (a), an organopolysiloxane having an alkenyl group was prepared, which was a vinylated polydimethylsiloxane having at least two vinyl groups per molecule (product name: DMS-V41, manufactured by Gelest Corporation, number average molecular weight: 68,000 (polystyrene equivalent), molar equivalent of vinyl group: 0.04 mmol/g).
Furthermore, as the organopolysiloxane having Si-H groups as component (b), a methylhydrogenpolysiloxane having at least two Si-H groups per molecule (product name: HMS-301, manufactured by Gelest, number average molecular weight 1300 (polystyrene equivalent), molar equivalent of Si-H groups 3.60 mmol/g) was prepared. 0.5 parts by mass of component (b) was added to 100 parts by mass of component (a) and thoroughly mixed to obtain an addition-curing silicone rubber stock solution.
Further, a trace amount of a catalyst for addition curing reaction (platinum catalyst: platinum carbonylcyclovinylmethylsiloxane complex) and an inhibitor (component (c)) were added and thoroughly mixed.
High purity spherical alumina (product name: Alnabeads CB-A10S; manufactured by Showa Titanium Co., Ltd.) as component (d) thermally conductive filler was mixed and kneaded into this addition-curing silicone rubber stock solution at a volume ratio of 45% based on the elastic layer, thereby obtaining an addition-curing silicone rubber composition having a JIS K 6253A durometer hardness of 10° after curing.

Next, an addition-curing silicone rubber adhesive (product name: SE1819CV A/B, manufactured by Dow Toray Industries, Inc.) for forming the adhesive layer 20f was applied uniformly to a thickness of about 20 μm onto the obtained elastic layer 20c. A fluororesin tube (product name: NSE, manufactured by Gunze Co., Ltd.) having an inner diameter of 29 mm and a thickness of 50 μm for forming the surface layer 20d was laminated on top of this while expanding its diameter.
After that, the belt surface was uniformly rubbed from above the fluororesin tube to rub out excess adhesive between the elastic layer 20c and the fluororesin tube to a thickness of about 5 μm. Next, the adhesive was cured by heating at 200° C. for 30 minutes to fix the fluororesin tube on the elastic layer 20c, and finally both ends were cut to a length of 240 mm to obtain a fixing rotor.

[Example 2]
A fixing rotatable member was produced in the same manner as in Example 1, except that the baking temperature of the conductive layer 20b was set to 350°C.

[Example 3]
A fixing rotatable member was produced in the same manner as in Example 1, except that the baking temperature of the conductive layer 20b was set to 400°C.

[Example 4]
The fixing rotor was manufactured in the same manner as in Example 1, except that the resin layer 20e was made of a polyimide precursor solution (U Varnish S, manufactured by Ube Industries), which was dried at 140°C for 30 minutes, baked at 200°C for 30 minutes and then baked at 400°C for 30 minutes to form the imidized resin layer 20e.

[Example 5]
A fixing rotatable member was produced in the same manner as in Example 4, except that the baking temperature of the conductive layer 20b was set to 350°C.

[Example 6]
A fixing rotatable member was produced in the same manner as in Example 4, except that the baking temperature of the conductive layer 20b was set to 400°C.

[Comparative Example 1]
A fixing rotatable member was produced in the same manner as in Example 1, except that the baking temperature of the conductive layer 20b was 150°C.

[Comparative Example 2]
A fixing rotatable member was produced in the same manner as in Example 4, except that the baking temperature of the conductive layer 20b was 150°C.

(Evaluation: Cross-sectional observation)
The cross sections of the conductive layers 20b of Examples 1 to 6 and Comparative Examples 1 and 2 were observed to confirm the presence or absence of pores penetrating in the thickness direction.
From the fixing rotor, for example, samples each having a length of 5 mm, a width of 5 mm, and a thickness equal to the entire thickness of the fixing rotor were taken from any six positions of the fixing member. The obtained samples were polished using an ion milling device (product name: IM4000, manufactured by Hitachi High-Technologies Corporation) so that the cross section of the conductive layer in the entire thickness direction was exposed. Polishing the cross section by ion milling can prevent particles from falling off the sample and abrasives from being mixed in, and can form a cross section with few polishing marks.

Next, the cross section in the thickness direction of the conductive layer 20b exposed on the polished surface of the sample was observed with a Schottky Field Emission Scanning Electron Microscope (product name: JSM-F100, manufactured by JEOL Ltd.) equipped with an energy dispersive X-ray analyzer (EDS), and a cross-sectional image was obtained. The observation conditions were a 20,000x backscattered electron image mode, and the backscattered electron image acquisition conditions were an acceleration voltage of 3.0 kV and a working distance of 3 mm. From the cross-sectional image thus obtained, it was determined whether the conductive layer 20b had pores penetrating in the thickness direction. Then, if a penetrating pore could be confirmed in any of the cross sections of the six conductive layers, it was determined that the observed fixing rotor was related to the present disclosure.

Furthermore, from the cross-sectional images, it was confirmed whether or not the resin constituting the resin layer 20e had penetrated into at least some of the penetrating pores.
Here, a cross-sectional image of the conductive layer observed in one of the samples taken from the fixing rotor according to Example 4 is shown in Fig. 9. It was confirmed from Fig. 9 that the conductive layer according to Example 4 had pores penetrating in the thickness direction. It was also confirmed from Fig. 9 that the resin constituting at least a part of the resin layer 20e had penetrated at least a part of the pores penetrating in the thickness direction of the conductive layer according to Example 4.
Furthermore, elemental analysis was performed on the cross section of the conductive layer exposed on the polished surface of the sample in the thickness direction at an acceleration voltage of 5 to 15 kV and a magnification of 4000 times using an EDS mounted on the "JSM-F100". The elemental analysis was performed on three arbitrary points on the cross section of the conductive layer 20b exposed on the polished surface of the sample. The arithmetic mean value of the silver purity obtained by performing the elemental analysis on three arbitrary points on the cross-sectional images of the six samples was determined as the silver purity of the conductive layer of the fixing belt related to the observation target.

(Evaluation: durability test)
For Examples 1 to 6 and Comparative Examples 1 and 2, a repeated bending test (MIT folding fatigue tester, manufactured by Toyo Seiki Co., Ltd.) was conducted, and peeling after the endurance test was observed. The test temperature was 200° C., the bending angle was 135°, and the bending curvature was 6 mm, and the specimen was bent 2 million times. Evaluation was then performed based on the following criteria.
Rank A: No peeling occurred even after bending 2 million times.
Rank B: The resin layer peeled off from the conductive layer after being bent less than 2 million times.

表１中、「Ａｇ」は銀を示し、「ＰＡＩ」は、ポリアミドイミドを示し、「ＰＩ」はポリイミドを示す。 The results are shown in Table 1. Note that, for the results of the durability tests of Comparative Examples 1 and 2, the number of times of bending at which peeling of the resin layer from the conductive layer was first observed is shown together with the evaluation rank.

In Table 1, "Ag" represents silver, "PAI" represents polyamideimide, and "PI" represents polyimide.

The term "through pores" was used when the conductive layer had through holes in the thickness direction. The term "penetration of resin into pores" was used when the resin constituting at least a part of the resin layer had penetrated at least a part of the through holes.
9, it can be seen that Example 4 has pores penetrating the conductive layer 20b in the thickness direction, and the resin layer 20e penetrates into the pores, reaches the substrate 20a, and contacts the substrate. It can also be seen that no interface is observed between the substrate 20a and the resin layer 20e, and they are bonded together. In the other examples, the resin layer was also in contact with the substrate.

Comparing the results in Table 1 with the examples and comparative examples, it can be seen that those in which the conductive layer 20b has pores penetrating in the thickness direction and the resin of the resin layer penetrates into the pores do not show peeling after the durability test and have good durability.

As described above, the present disclosure can be used for a fixing rotor having a conductive layer that is highly conductive and durable.

The present disclosure relates to the following configurations.
(Configuration 1)
A fixing rotor,
The fixing rotor is
A substrate including a resin;
a conductive layer on the substrate;
a resin layer on a surface of the conductive layer opposite to a surface facing the substrate,
the conductive layer extends in a circumferential direction on an outer circumferential surface of the base material,
the conductive layer comprises silver;
the conductive layer has through holes in a thickness direction,
a resin constituting at least a part of the resin layer penetrates at least a part of the through-hole;
A fixing rotating body characterized by the above-mentioned.
(Configuration 2)
2. The fixing rotatable member according to claim 1, wherein the resin constituting the resin layer includes at least one selected from the group consisting of polyimide and polyamideimide.
(Configuration 3)
3. The fixing rotating member according to claim 1, wherein the resin contained in the base material includes at least one selected from the group consisting of polyimide and polyamideimide.
(Configuration 4)
4. The fixing rotating member according to any one of configurations 1 to 3, wherein the conductive layer has a maximum thickness of 4 μm or less.
(Configuration 5)
5. The fixing rotating member according to any one of configurations 1 to 4, wherein the resin constituting the resin layer that penetrates into the through holes is in contact with the base material.
(Configuration 6)
The fixing rotating member according to any one of configurations 1 to 5, wherein the conductive layer is a sintered body of silver nanoparticles.
(Configuration 7)
A fixing rotating body according to any one of configurations 1 to 6,
and an induction heating device for generating heat from the fixing rotatable body by induction heating.
(Configuration 8)
The induction heating device is
an excitation coil disposed inside the fixing rotor, the excitation coil having a helical portion whose helical axis is substantially parallel to a direction along the rotation axis of the fixing rotor, for generating an alternating magnetic field that generates heat in the conductive layer by electromagnetic induction;
a magnetic core disposed in the spiral portion, extending in the direction of the rotation axis and not forming a loop outside the fixing rotor, the magnetic core for inducing magnetic lines of the alternating magnetic field;
Equipped with
The magnetic core is made of a ferromagnetic material,
8. The fixing device according to claim 7, wherein the conductive layer is primarily heated by an induced current induced by magnetic field lines that originate from one longitudinal end of the magnetic core, pass outside the conductive layer, and return to the other longitudinal end of the magnetic core.
(Configuration 9)
1. An electrophotographic image forming apparatus, comprising:
The electrophotographic image forming apparatus comprises:
an image carrier that carries a toner image;
a transfer device for transferring the toner image onto a recording material;
a fixing device for fixing the transferred toner image onto the recording material;
Equipped with
9. An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to configuration 7 or 8.

REFERENCE SIGNS LIST 1 image forming apparatus, 15 fixing device, 20 fixing rotor, 20a substrate, 20b conductive layer, 20c elastic layer, 20d surface layer, 20e resin layer, 20f adhesive layer, 21 pressure roller

Claims (9)

A fixing rotor,
The fixing rotor is
A substrate including a resin;
a conductive layer on the substrate;
a resin layer on a surface of the conductive layer opposite to a surface facing the substrate,
the conductive layer extends in a circumferential direction on an outer circumferential surface of the base material,
the conductive layer comprises silver;
the conductive layer has through holes in a thickness direction,
a resin constituting at least a part of the resin layer penetrates at least a part of the through-hole;
A fixing rotating body characterized by the above-mentioned. The fixing rotor according to claim 1, wherein the resin constituting the resin layer includes at least one selected from the group consisting of polyimide and polyamideimide. The fixing rotor according to claim 2, wherein the resin contained in the base material includes at least one selected from the group consisting of polyimide and polyamideimide. The fixing rotor according to claim 1, wherein the maximum thickness of the conductive layer is 4 μm or less. The fixing rotor according to claim 1, wherein the resin constituting the resin layer that penetrates the through-holes is in contact with the substrate. The fixing rotor according to claim 1, wherein the conductive layer is a sintered body of silver nanoparticles. A fixing rotating body according to any one of claims 1 to 6,
and an induction heating device for generating heat from the fixing rotatable body by induction heating. The induction heating device is
an excitation coil disposed inside the fixing rotor, the excitation coil having a helical portion whose helical axis is substantially parallel to a direction along the rotation axis of the fixing rotor, for generating an alternating magnetic field that generates heat in the conductive layer by electromagnetic induction;
a magnetic core disposed in the spiral portion, extending in the direction of the rotation axis and not forming a loop outside the fixing rotor, the magnetic core for inducing magnetic lines of the alternating magnetic field;
Equipped with
The magnetic core is made of a ferromagnetic material,
8. The fixing device according to claim 7, wherein the conductive layer generates heat mainly by an induced current induced by magnetic field lines that extend from one longitudinal end of the magnetic core, pass outside the conductive layer, and return to the other longitudinal end of the magnetic core. 1. An electrophotographic image forming apparatus, comprising:
The electrophotographic image forming apparatus comprises:
an image carrier that carries a toner image;
a transfer device for transferring the toner image onto a recording material;
a fixing device for fixing the transferred toner image onto the recording material;
Equipped with
8. An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to claim 7.

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