JP2024063761A - Rotating body for fixing - Google Patents

Abstract

[Problem] To provide a fixing rotor having high conductivity and excellent durability. [Solution] The fixing rotor comprises a cylindrical substrate containing at least a resin, a conductive layer on the substrate, and a resin layer on a surface of the conductive layer opposite to the side facing the substrate, the conductive layer extending in the circumferential direction of the outer circumferential surface of the substrate and containing silver, the conductive layer having a volume resistivity of 1.0×10-8 to 8.0×10-8 Ω·m, and the conductive layer has an average compressive elastic modulus of 8 to 30 GPa in a thickness region of 0.1 to 0.2 μm deep from the first surface of the conductive layer, measured by contacting an indenter with a first surface opposite to the surface facing the substrate. [Selected Figure] Figure 7

Description

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

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.
The conductive layer is required to have electrical conductivity and durability against repeated strain under heating. For example, Patent Document 1 discloses a fixing member having a conductive layer formed by copper plating.

JP 2021-51136 A

At least one aspect of the present disclosure is directed to providing a fixing rotor having high conductivity and excellent durability. At least one aspect of the present disclosure is directed to providing a fixing device that contributes to the stable formation of high-quality electrophotographic images. Furthermore, at least one aspect of the present disclosure is directed to an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images.

According to one aspect of the present disclosure,
A cylindrical substrate containing at least 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 is
The groove extends in a circumferential direction of the outer peripheral surface of the substrate, and
Contains silver,
the volume resistivity of the conductive layer is 1.0×10 ⁻⁸ to 8.0×10 ⁻⁸ Ω·m;
The fixing rotor has an average compressive elastic modulus of 8 to 30 GPa in a region 0.1 to 0.2 μm from the first surface of the conductive layer in the thickness direction, as measured by bringing an indenter into contact with the first surface of the conductive layer opposite to the surface facing the substrate.

According to another aspect of the present disclosure, the fixing rotor and
and an induction heating device for heating the fixing rotatable body by induction heating.

According to yet another 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 in which the fixing device is the fixing device described above.

According to still another aspect of the present disclosure, there is provided a method for manufacturing the fixing rotor, comprising the steps of:
(i) obtaining the substrate;
(ii) applying a silver nanoparticle ink to the outer peripheral surface of the substrate obtained in step (i) and baking the ink to obtain a conductive layer;
(iii) applying a resin material onto the conductive layer obtained in the step (ii) and baking the applied resin material to obtain a resin layer;
The present invention provides a method for manufacturing a fixing rotor having the above structure.

According to one aspect of the present disclosure, a fixing rotor having high conductivity and excellent durability can be obtained. According to another aspect of the present disclosure, a fixing device using the fixing rotor can be obtained. According to another aspect of the present disclosure, an electrophotographic image forming apparatus using the fixing device can be obtained.

Cross-sectional image of conductive layer (photo instead of drawing) 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 perspective view 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;

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 improved durability of fixing members. When paper of different sizes is inserted into a fixing member, pressure is applied locally to the edge of the paper, the so-called paper edge, so durability against partial compression load is required. In particular, in a configuration in which multiple conductive layers are formed on the outer peripheral surface of a base layer as disclosed in Patent Document 1, when the paper edge is repeatedly subjected to compression deformation, if the difference in compressive strain between the conductive layer and the resin layer is large, stress concentration increases at the interface between the resin layer and the conductive layer, and there is a concern that buckling may occur. In other words, it has been found that if the difference in rigidity between the conductive layer and the base layer or the conductive layer and the resin layer is large, a durability issue occurs in which cracks occur along the conductive layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fixing rotatable member according to one embodiment of the present disclosure, and a fixing device and an electrophotographic image forming apparatus made 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.
FIG. 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 housed in the lower part of the printer 1 so as to be removable. The cassette 2 holds a stack of sheets P as recording material. The sheets P in the cassette 2 are separated one by one by a separation roller 3 and fed to a registration roller 4. Note that as the recording material, sheets P, which may be used, include a variety of sheets of different sizes and materials, such as paper such as plain paper and cardboard, sheet materials with a surface treatment such as plastic film, cloth, and coated paper, and sheet materials with special shapes such as envelopes and index paper.

The printer 1 is equipped with an image forming unit 5 as an image forming means, which is a horizontal row of image forming units 5Y, 5M, 5C, and 5K corresponding to the colors yellow, magenta, cyan, and black. The image forming unit 5Y is equipped with a photosensitive drum 6Y, which is an image carrier (electrophotographic photosensitive body), and a charging roller 7Y, which is a charging means for uniformly charging the surface of the photosensitive drum 6Y. In addition, a scanner unit 8 is disposed below the image forming unit 5. The scanner unit 8 irradiates a laser beam that is on/off modulated in response to a digital image signal input from an external device such as a computer (not shown) based on image information and generated by an image processing means, to form an electrostatic latent image on the photosensitive drum 6Y.

Furthermore, the image forming unit 5Y includes a developing roller 9Y as a developing means that adheres toner to the electrostatic latent image on the photosensitive drum 6Y to develop it into a toner image, and a primary transfer unit 11Y that transfers the toner image on the photosensitive drum 6Y to the intermediate transfer belt 10.
Toner images formed by the same process in other image forming units 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 the primary transfer unit 11Y and the secondary transfer unit 12 are exemplified as the fixing device, the fixing device may be, for example, a direct transfer fixing device that directly transfers a toner image from an image carrier to a sheet P. The image forming device may also be configured as a monochrome device 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 conveyance direction of the recording material and the thickness direction of the recording material, that is, the rotation axis direction of the fixing rotor 20.

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, a thermistor 40, and a current sensor 30. The fixing device 15 heats the recording material on which an image is formed, and fixes the image to the recording material. The fixing rotor 20 is the fixing 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 substrate 20a, a conductive layer 20b on the outer surface of the substrate 20a, and a resin layer 20e on the surface of the conductive layer opposite to the side facing the substrate.
As shown in FIG. 4, the conductive layer 20b can be composed of a plurality of electrically independent conductive regions 201 (FIG. 4) in a cross-sectional view in the longitudinal direction X1 (the direction of the rotation axis of the fixing rotor 20) perpendicular to the circumferential direction of the fixing rotor 20. That is, the conductive layer 20b can include a plurality of ring-shaped conductive regions each extending in the circumferential direction of the fixing rotor 20 and electrically independent from each other. The plurality of conductive regions being electrically independent from each other means that each of the conductive regions can independently generate heat by electromagnetic induction. It is preferable that each of the plurality of conductive regions 201 is formed with a uniform width in the longitudinal direction X1.

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

As shown in FIG. 4, compression springs 24a and 24b are respectively provided between both longitudinal ends of the compression stay 22 and spring bearing members 23a and 23b on the device chassis side, so that a downward force acts on the compression stay 22.

The fixing device 15 of this embodiment applies a total pressure of approximately 100N to 300N (approximately 10kgf to approximately 30kgf). As a result, the lower surface of the film guide 25, which is made of a heat-resistant resin such as polyphenylene sulfide (PPS), and the upper surface of the pressure roller 21 are pressed against the fixing rotor 20, which is a cylindrical rotor, to form a fixing nip N of a predetermined width. The film guide 25, together with the pressure roller 21, functions as a nip forming member that forms a nip that sandwiches and conveys the recording material carrying the toner image via the fixing rotor 20.

The pressure roller 21 is driven to rotate in a clockwise direction by a driving means (not shown), and exerts a counterclockwise rotational force 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 shown 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 periphery of the magnetic core 26 and extends in the longitudinal direction. 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 the 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, forming a path (magnetic path) for the magnetic field lines. The material of the magnetic core 26 is a ferromagnetic material. The material of the ferromagnetic magnetic core 26 is preferably a material with small hysteresis loss and high relative permeability, such as 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 housed in the hollow portion of the fixing rotor 20, but it is preferable that the cross-sectional area be as large as possible. In this embodiment, the diameter of the magnetic core 26 is 10 mm, and the length in the longitudinal direction is 280 mm.

The excitation coil 27 is formed by winding a 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 outer periphery of the magnetic core 26 in a direction intersecting the direction of the rotation axis of the fixing rotor 20. Therefore, when a high-frequency alternating current is applied to the excitation coil 27, an alternating magnetic field is generated in a direction parallel to the direction of the rotation axis of the fixing rotor 20, and an induced current (circulating current) flows in each heating ring 201 of the conductive layer 20b of the fixing rotor 20 according to a 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 held in contact with the inner surface. The thermistor 40 may also be disposed on the outer periphery of the fixing rotor 20.

The current sensor 30 constituting the continuity monitoring device that monitors the circumferential continuity of the conductive layer 20b is disposed 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 rotatable body 20 in the fixing device 15 of the induction heating type will be described.
6 is a conceptual diagram showing a magnetic field formed when a current is passed through the excitation coil 27 in the direction of the arrow I0. The excitation coil 27 is wound around the outer periphery of the magnetic core 26 inserted into the fixing rotor 20, and functions as a magnetic field generating means for generating an induced current I in the circumferential direction of the fixing rotor 20 by passing an alternating current through the excitation coil 27.
Further, the magnetic core 26 functions as a member that induces magnetic lines of force B (dotted lines in FIG. 6) generated by the excitation coil 27 and forms a magnetic path.

In a typical induction heating type fixing device, magnetic field lines penetrate the conductive layer to generate eddy currents. In contrast, in this embodiment, the magnetic field lines B are configured to 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. In this way, heat can be generated efficiently even if 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.

7 is a cross-sectional view of the fixing rotor in the circumferential direction. The fixing rotor has a cylindrical substrate 20a containing at least a resin, a conductive layer 20b on the substrate 20a, and a resin layer 20e on the surface of the conductive layer opposite to the substrate. 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 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 contained in the substrate 20a (preferably the resin constituting the substrate) is preferably 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.

In the fixing rotating body, the material of the base material 20a can be analyzed by the following procedure.
A sample of 10 mm square is cut out from the fixing rotor, and if there is an elastic layer or a surface layer, it is removed with a razor, a solvent, etc. The material can be confirmed by performing an ATR measurement on the obtained sample using an infrared spectrometer (FT-IR) (for example, product name: Frontier FT IR, manufactured by PerkinElmer).
The material of the resin layer described below can also be analyzed in the same manner as above.

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 rotary member, and can be, for example, an endless belt shape, a hollow cylinder shape, a film shape, or various other shapes.
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 extends in the circumferential direction of the outer circumferential surface of the base material, and generates heat when electricity 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 an induced current flows in the conductive layer 20b of the fixing rotor due to the magnetic field, generating heat due to Joule heat.

The conductive layer 20b is preferably made of silver, which has a low volume resistivity and is resistant to oxidation.
By including silver in the conductive layer 20b, the conductivity required for the conductive layer can be maintained, and the occurrence of image defects can be prevented. In addition, deterioration due to oxidation can be suppressed, and durability can be improved. 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 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 analysis of silver in the conductive layer can be carried out, for example, by the following procedure.
From the fixing rotor, 20 samples each having a length of 5 mm, a width of 5 mm, and a thickness of the entire thickness of the fixing rotor are taken from any point of the fixing rotor. For the obtained 20 samples, the cross section in the circumferential direction of the fixing rotor is exposed with a cross-section polisher (product name: SM09010, manufactured by JEOL Ltd.). Next, the exposed cross section of the 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 20,000 times 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 designated by area, and adjusted to select only the silver crystal particles in the observed image.
One image is taken for one sample, and EDS analysis is performed at three points within one image. The purity is analyzed at a total of 60 points for six samples, and the arithmetic average value is calculated to determine the purity of the silver that constitutes the conductive layer.

The conductive layer 20b preferably has a maximum thickness Te of 4 μm or less, which allows the fixing rotor to have an appropriate degree of flexibility and a small heat capacity.
Moreover, by setting the maximum thickness Te to 4 μm or less, the bending resistance performance 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 in the fixing nip portion N, and is subjected to stress. It is preferable to design the conductive layer 20b of the fixing rotor 20 so that it does not break due to fatigue even if this repeated bending is continued until the endurance life of the fixing device.

Reducing the thickness of the conductive layer 20b significantly improves the resistance of the conductive layer 20b to fatigue failure. 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 becomes thinner. Furthermore, reducing the thickness of the conductive layer can further shorten the time required for the conductive layer to generate sufficient heat.

For the above reasons, it is preferable that the maximum thickness Te of the conductive layer 20b is set to 4 μm or less.
The maximum thickness Te of the conductive layer is more preferably 3 μm or less. The lower limit of the thickness of the conductive layer is not particularly limited, but is preferably 1 μm or more from the viewpoint of maintaining durability. The maximum thickness Te of the conductive layer is preferably in the range of, for example, 1 to 4 μm, particularly 1 to 3 μm.

The maximum thickness Te of the conductive layer on the fixing rotary member can be measured 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 of the conductive layer in the image, and the arithmetic average value of the six samples was defined as the maximum thickness Te. The parallel lines were drawn based on the surface of the substrate opposite the conductive layer in the observation area.

The volume resistivity of the conductive layer is 1.0×10 ⁻⁸ to 8.0×10 ⁻⁸ Ω·m. By setting the volume resistivity of the conductive layer in the above range, the conductivity required for the conductive layer can be maintained, and the occurrence of image defects can be prevented.
The volume resistivity of the conductive layer is preferably 2.0×10 ⁻⁸ Ω·m or more, and more preferably 2.5×10 ⁻⁸ Ω·m or less. Also, it is preferably 7.0×10 ⁻⁸ Ω·m or less, and more preferably 6.0×10 ⁻⁸ Ω·m or less. For example, it is preferably in the range of 2.0×10 ⁻⁸ to 7.0×10 ⁻⁸ Ω·m, or 2.0×10 ⁻⁸ to 6.0×10 ⁻⁸ Ω·m.

The volume resistivity of the conductive layer can be controlled, for example, by the material of the conductive layer and the manufacturing method of the conductive layer. Specifically, the volume resistivity can be increased by using silver as the material of the conductive layer. Also, specifically, for example, when the conductive layer is formed using silver nanoink, the higher the baking temperature of the silver nanoink film formed on the surface of the substrate, the lower the volume resistivity of the conductive layer can be obtained. This is because organic materials such as dispersants contained in the silver nanoink volatilize during the baking process at high temperatures, resulting in a conductive layer with a low content of components other than silver.

The volume resistivity of the conductive layer can be measured, for example, by resistance measurement using a four-probe method (JIS K 7194).
In the present disclosure, the volume resistivity is measured using a low-resistance resistivity meter (Loresta GX MCP-T700, manufactured by Nitto Seiko Analytech Co., Ltd.) in accordance with JIS K 7194: 1994. Specifically, the volume resistivity is measured by the following method.
The surface layer and the elastic layer are peeled off from the fixing rotor, and the laminate of the base layer, the conductive layer, and the resin layer is taken out. Next, the base layer and the resin layer are removed using a solvent (e-solv 21KZE-100, manufactured by Kaneko Chemical Co., Ltd.) to obtain a conductive layer. The volume resistivity is measured by directly contacting the measuring probe of the above-mentioned device with the obtained conductive layer. The probe to be used may be selected according to the width of the conductive layer. For example, if the width of the conductive layer is 200 μm, a probe with an electrode diameter of 150 μm is selected. The resistance value of the conductive layer is determined by measuring the resistance values of multiple conductive layers, and the average value is taken as the volume resistivity of the conductive layer of the member.

As described above, the conductive layer 20b can be configured with a plurality of electrically independent ring-shaped conductive regions 201 in the longitudinal direction perpendicular to the circumferential direction of the fixing rotor (see FIG. 4). With this configuration, even if a crack occurs in one of the conductive regions 201, making it difficult to generate heat, the heat generation capacity of the conductive layer 20b as a whole is unlikely to be significantly affected.

As described above, when the conductive layer 20b is composed of multiple conductive regions 201, the total surface area of the conductive layer 20b increases, making it relatively more susceptible to oxidation. However, by using silver as the material for the conductive layer, deterioration of the conductive layer due to oxidation can be effectively suppressed.

4, when the conductive layer 20b is composed of a plurality of conductive regions 201, the width of each conductive region in a longitudinal cross-sectional view of the fixing rotor is preferably 100 μm or more, more preferably 200 μm or more, from the viewpoint of providing good heat generation performance. From the viewpoint of suppressing uneven heat generation, the width is preferably 500 μm or less, more preferably 400 μm or less. The width of each conductive region is, for example, preferably in the range of 100 to 500 μm, or 200 to 400 μm. It is also preferable that the width of each conductive region is approximately constant.
The distance between the conductive regions of the conductive layer 20b is preferably 50 μm or more, more preferably 100 μm or more, from the viewpoint of preventing short circuits between the conductive regions. Also, from the viewpoint of suppressing uneven heat generation of the fixing rotor, the distance is preferably 400 μm or less, more preferably 300 μm or less. The distance between the conductive regions is, for example, preferably 50 to 400 μm, more preferably 100 to 300 μm.

It is desirable that the difference between the compressive modulus of the conductive layer 20b in the compression direction and the compressive modulus of the substrate or resin layer is small. If the difference in the compressive modulus of the conductive layer and the substrate or resin layer is small, excessive stress can be prevented from being applied to the interface between the conductive layer and the substrate or resin layer when the edge of the paper, the so-called paper edge, is locally compressed and deformed. As described above, it is desirable that the substrate is composed mainly of a heat-resistant resin. Therefore, it is desirable that the compressive modulus of the conductive layer 20b is as low as possible, even if it is mainly composed of silver.

The compressive elastic modulus of the conductive layer in the compression direction is 8 to 30 GPa.
The compressive elastic modulus of the conductive layer is measured by contacting a Berkovich type indenter with a first surface of the conductive layer opposite to the surface facing the base layer, indenting the indenter to a depth of 1 μm from the first surface, and measuring the compressive elastic modulus at each depth position. Then, the average value of the compressive elastic modulus at each depth position in a depth region of 10 to 20% of the indentation depth, i.e., a depth region of 0.1 μm to 0.2 μm from the first surface, is calculated. The average value is then regarded as the compressive elastic modulus of the conductive layer.
The compressive elastic modulus of the conductive layer is preferably 25 GPa or less, and more preferably 20 GPa or less. The lower limit of the compressive elastic modulus is 8 GPa or more from the viewpoint of durability of the conductive layer. The range of the compressive elastic modulus of the conductive layer is, for example, preferably 8 to 25 GPa, and more preferably 8 to 20 GPa.

By setting the compressive elastic modulus of the conductive layer within the above range, the difference between the compressive elastic modulus of the conductive layer and the compressive elastic modulus of the resin material used in the substrate can be reduced, which can prevent excessive stress from being applied to the interfaces between the conductive layer and the substrate or the resin constituting the resin layer, thereby improving durability.
The compressive elastic modulus of the conductive layer is preferably within 6 times the compressive elastic modulus of the substrate, which is measured in the same manner as the compressive elastic modulus of the elastic layer.
Specifically, the Berkovich indenter is pressed to a depth of 1 μm from the first surface of the substrate opposite to the surface on which the conductive layer is formed, and the compressive modulus at each depth is measured. The average value of the compressive modulus in the thickness region of 0.1 to 0.2 μm from the first surface of the base layer is taken as the compressive modulus of the substrate. The compressive modulus of a 40 μm thick substrate made of polyimide, which is a preferred substrate material, is, for example, 5 GPa. For this reason, it is preferable that the compressive modulus of the conductive layer formed on the polyimide substrate is 6 times or less than the compressive modulus of the substrate, that is, 30 GPa or less. When the substrate is made of resin, the average compressive modulus of the substrate is preferably 2.5 to 6.0 GPa.

The compressive elastic modulus of the conductive layer is preferably 25 GPa or less, and even more preferably 20 GPa or less. From the viewpoint of the durability of the conductive layer, the lower limit of the compressive elastic modulus is preferably 8 GPa or more. The compressive elastic modulus of the conductive layer is preferably, for example, in the range of 8 to 25 GPa, or 8 to 20 GPa.

The conductive layer can be provided with pores to reduce the compressive modulus while maintaining the required conductivity. By providing pores in the conductive layer, when the conductive layer is subjected to localized compressive stress, the conductive layer can deform in accordance with the deformation of the resin constituting the substrate and the resin layer, and can dissipate excess stress. As a result, the occurrence of cracks can be suppressed and the durability of the conductive layer can be improved.
The larger the size and ratio of the pores in the conductive layer, the lower the compressive elastic modulus of the conductive layer can be kept. However, if the porosity of the conductive layer is too large, problems arise in the conductivity and durability, so it is desirable to adjust the size and ratio of the pores so that the compressive elastic modulus of the conductive layer does not fall below 8 GPa.

The method of forming voids in the conductive layer 20b is not particularly limited, but examples include a method of forming a pattern on the conductive layer 20b by a photolithography process and then forming voids by chemical etching, and a method of forming voids using a laser or focused ion beam. In this disclosure, in particular, void formation using a silver nanoparticle material will be described.

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

Furthermore, by baking (sintering) the laminate with the silver nanoparticles formed at 300°C to 400°C, the nano-sized voids in the film coalesce to form larger voids, and eventually through-holes opening on both the surface on the substrate side and the surface opposite the substrate side are formed as shown in Figure 8 (c). In other words, when forming a conductive layer using silver nanoink, the number and size of voids can be adjusted by increasing the baking temperature of the silver nanoink layer formed on the surface of the substrate and by extending the baking time.

The size and number of pores in the conductive layer can be expressed as the porosity, which is determined as follows.
(Preparation of evaluation samples)
First, a sample for evaluation is prepared by taking one sample having a length of 5 mm, a width of 5 mm, and a thickness corresponding to the entire thickness of the fixing rotor from an arbitrary position of the fixing rotor.
The obtained sample is polished by using an ion beam to the cross section in the circumferential direction of the fixing rotor. At this time, the processing position is adjusted so that the cross section in the circumferential direction of the conductive layer is exposed by the polishing of the ion beam. The method of polishing the cross section by the ion beam is not particularly limited, but in the present disclosure, a cross-section polisher is used. In the polishing of the cross section by the ion beam, it is possible to prevent the filler from falling off the sample and the abrasive from being mixed in, and also to form a cross section with few polishing marks.

(Cross-section observation of conductive layer and image processing)
The cross section of the conductive layer obtained by the above method is observed with a scanning electron microscope (SEM) (product name: JSM-F100, manufactured by JEOL Ltd.) to obtain a cross section image (SEM image). The observation conditions are a backscattered electron image mode at 20,000 magnification, and the backscattered electron image acquisition conditions are an acceleration voltage of 3.0 kV and a working distance of 3 mm.
Fig. 1 shows an example of an SEM image of a cross section of a fixing rotor 100. As shown in Fig. 1, the fixing rotor 100 includes a substrate 101, a conductive layer 103 on the substrate, and a resin layer 105 on the conductive layer. An example of the conductive layer 103 includes silver crystals 103-1. The conductive layer 103 also has at least one void 107.
The SEM image obtained above is subjected to binarization processing so that crystal grains are displayed in white and non-crystal grains are displayed in black. As a binarization method, for example, Otsu's method can be used.
Specifically, first, a backscattered electron image was read using image analysis software (ImageProPlus, manufactured by MediaCybernetics), and a 0.5 μm×0.5 mm pixel size was obtained at any point.
The image is cut out in the range of μm, and the brightness distribution of this image is obtained. Next, by setting the brightness range of the obtained brightness distribution, binarization can be performed to distinguish between crystal grains and other parts.

(Calculation of porosity)
In the binarized image obtained by the above procedure, each metal crystal particle is represented as a white area. The porosity is calculated by calculating the area that each crystal particle occupies in the image.
Specifically, the number of pixels that are composed of crystal particles in the binarized image is calculated, and the total number of pixels is calculated. The total number of pixels is multiplied by the area of one pixel (0.15×0.15=0.0225 μm ² ) to calculate the area occupied by the crystal particles.
The porosity indicates the proportion of space in the conductive layer that is not occupied by crystal grains, and is calculated as follows using the area occupied by the crystal grains calculated above.
Porosity={area of binarized image (0.5×0.5 (μm ² ))−area occupied by crystal grains (μm ² )}÷area of binarized image (0.5×0.5 (μm ² ))×100
The above porosity is measured at any 20 points on the binarized image of the cross section of the conductive layer, and the average porosity obtained by averaging is regarded as the porosity of the conductive layer.

The porosity of the conductive layer is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more. By setting the porosity within the above range, it is possible to reduce the compressive elastic modulus while maintaining the conductivity required for the conductive layer.
From the viewpoint of electrical conductivity and durability, the upper limit of the porosity of electrical conductivity is preferably 50% or less, more preferably 48% or less, and even more preferably 45% or less. By setting it in the above range, electrical conductivity and durability can be compatible. For example, preferred ranges include 15 to 50%, 20 to 48%, and 25 to 45%.

When the pores are formed by using a silver nanoparticle material by the above method, the porosity can be controlled by the firing temperature when forming the conductive layer. Specifically, the higher the firing temperature, the greater the porosity because the fusion of silver nanoparticles is promoted.
The baking temperature of the conductive layer is preferably 100° C. or higher, and more preferably 150° C. or higher. By setting the baking temperature within the above range, it is possible to provide pores to a degree sufficient for improving durability.
The firing temperature of the conductive layer is preferably 400° C. or less, more preferably 350° C. or less. By setting the firing temperature within the above range, the porosity does not become too high, and the conductivity and durability of the conductive layer can be maintained. For example, the firing temperature is preferably in the range of 100 to 400° C. or 150 to 350° C.
The baking time for the conductive layer is not particularly limited, but may be, for example, in the range of 10 to 120 minutes.

(4) Resin Layer The fixing rotor has a resin layer 20e on the surface opposite to the conductive layer facing the substrate. 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 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 base material 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 the resin layer 20e preferably includes 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. The method of forming the substrate 20a and the resin layer 20e is not particularly limited. For example, an imide-based material can be formed into a film by applying a liquid called varnish using a known method and baking it.
The material of the resin layer can be analyzed in the same manner as the analysis of the material of the substrate described above.

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. From the viewpoint of the bending resistance of the conductive layer 20b, the thickness of the resin layer 20e is preferably the same as that of the substrate 20a. For example, the ratio of the difference in thickness between the substrate and the resin layer to the thickness of the substrate is preferably 20% or less, 10% or less, or 5% or less. By reducing the difference in thickness, when the conductive layer 20b is repeatedly bent at the nip portion, the stress applied to the conductive layer 20b is not biased, and the occurrence of cracks in the conductive layer 20b can be suppressed.

(5) Elastic Layer The fixing rotor may have an elastic layer on the outer surface of the resin layer 20e as necessary. 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 contacts the toner on the paper, the elastic layer 20c also functions as a layer for imparting flexibility to the surface of the heating member so that it 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 a function of imparting elasticity to the elastic layer 20c. From the viewpoint of imparting the above-mentioned function of the elastic layer 20c, the matrix preferably contains silicone rubber.
Silicone rubber is preferable because it has high heat resistance that allows it to maintain flexibility even in an environment where the temperature in the non-paper passing area reaches a high temperature of about 240° C. As the silicone rubber, for example, a cured product of an addition curing type liquid silicone rubber composition described later 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 may be an organopolysiloxane having an unsaturated aliphatic group such as a vinyl group, for example, those represented by the following formulas (1) and (2).

In formula (1), ^m1 represents an integer of 0 or more, and ⁿ¹ represents an integer of 3 or more. Each ^R1 independently represents a monovalent unsubstituted or substituted hydrocarbon group that does not contain an unsaturated aliphatic group, and at least one of the ^R1 represents a methyl group. 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 that does not contain an unsaturated aliphatic group, and at least one of ^R3 represents a methyl group. Each ^R4 independently represents an unsaturated aliphatic group.

In formula (1) and formula (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 groups: alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl), aryl groups (e.g., phenyl).
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 formula (1) and formula (2) each have at least one methyl group bonded directly to a silicon atom forming a 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 even more preferred that all ^R1 and ^R3 are methyl groups.

In addition, examples of unsaturated aliphatic groups that can be represented by R ² and R ⁴ in formula (1) and formula (2) include a vinyl group, an allyl group, a 3-butenyl group, a 4-pentenyl group, a 5-hexenyl group, etc. Among these groups, it is preferable that both R ² and R ⁴ 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 to 50000 mm ² /s. If the viscosity (kinetic viscosity) is lower than 1000 mm ² /s, it becomes difficult to adjust the hardness required for the elastic layer 20c, and if it is higher 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 greater, and ⁿ³ represents an integer of 3 or greater. Each ^R5 independently represents a monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group.

In formula (4), ^m3 represents an integer of 0 or more, and ⁿ⁴ represents an integer of 3 or more. 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 formula (3) and formula (4) include groups similar to ^R1 in formula (1) above. 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 to 50 μm from the viewpoints of handling and dispersibility. The shape of the filler may be spherical, pulverized, needle-like, plate-like, whisker-like, etc. 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 a surface layer 20d (described later).
The adhesive layer 20f is a layer for bonding 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 used in the adhesive layer f can contain, for example, a self-adhesive component, an organopolysiloxane having multiple unsaturated aliphatic groups, such as vinyl groups, in the molecular chain, a hydrogen organopolysiloxane, and a platinum compound as a cross-linking catalyst. The adhesive applied to the surface of the elastic layer 20c can be hardened 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 1 to 4, preferably 1 to 2, aromatic rings such as phenylene structures having a valence of 1 to 4, preferably 2 to 4, in one molecule, and at least 1, preferably 2 to 4, functional groups capable of contributing to a hydrosilylation addition reaction (e.g., alkenyl groups, (meth)acryloxy groups).

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 disclosure. 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 appropriately. Such addition curing type silicone rubber adhesives are commercially available and can be easily obtained. The thickness of the adhesive layer 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 the heat from the inner surface side can be easily transferred to the recording medium.

(7) Surface Layer The fixing rotor may have a surface layer 20d as required.
The surface layer 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 the formation of the surface layer, for example, a resin exemplified below may be molded into a tube shape, or a resin dispersion may be coated and molded.
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 to 50 μm. By keeping the thickness of the surface layer 20d within the above range, it is easy to maintain an appropriate surface hardness of the fixing rotor.

According to one aspect of the present disclosure, a fixing device is provided in which the above-described fixing rotor is disposed. Therefore, it is possible to provide a fixing device in which a fixing rotor that is highly conductive and has excellent durability is disposed. It is also possible to provide an image forming device that uses the above-described fixing device.

(8) Manufacturing Method of Rotating Body for Fixing The following is a non-limiting example of a manufacturing method of a rotating body for fixing (pressure belt or pressure roller) according to one embodiment of the present disclosure, which comprises a substrate, a conductive layer on the substrate, and a resin layer on the surface of the conductive layer opposite to the side facing the substrate, and the conductive layer contains silver. As a manufacturing method using a silver nanoparticle material, for example, a method including the following steps (i) to (iii) is mentioned.
(i) obtaining the substrate;
(ii) applying a silver nanoparticle ink to the outer peripheral surface of the substrate obtained in step (i) and baking the ink to obtain a conductive layer;
(iii) A step of applying a resin material onto the conductive layer obtained in the step (ii), followed by baking to obtain a resin layer.

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 and a length of 460 mm in a longitudinal direction perpendicular to the circumferential direction was prepared. A release treatment was applied to the outer peripheral surface of this stainless steel mold.
Next, the stainless steel mold was completely immersed in a polyimide precursor solution (product name: U Varnish S, manufactured by Ube Industries, Ltd.) to form a coating of the polyimide precursor solution on the outer circumferential surface. The coating was heated at a temperature of 140° C. for 30 minutes to volatilize the solvent in the coating, and then the coating was heated at a temperature of 200° C. for 30 minutes and subsequently at a temperature of 400° C. for 30 minutes. In this way, a polyimide film having a thickness of 40 μm was formed on the outer surface of the cylindrical stainless steel mold.
The polyimide film was then removed from the stainless steel mold to obtain a polyimide tube, which was then cut at both longitudinal ends perpendicular to the circumferential direction to obtain a polyimide tube with a length of 300 mm.

The polyimide tube obtained above was placed on the outer peripheral surface of a core having an outer diameter of 30 mm and a longitudinal length of 300 mm. Next, an ink containing silver nanoparticles (trade name: DNS163, manufactured by Daicel Corporation) was applied in the entire circumferential direction to a region of 110 mm from the center of the longitudinal direction of the outer surface of the polyimide tube toward both ends (hereinafter also referred to as the "central region", the longitudinal length of the central region = 220 mm) using an inkjet method to form a ring-shaped conductive area. After application, the ink was baked at a temperature of 300 ° C. for 30 minutes to form a conductive layer consisting of multiple ring-shaped conductive areas. Each of the obtained conductive areas had a longitudinal length of 300 μm, an interval of 200 μm, and a maximum thickness of 2 μm.

Next, a polyimide precursor solution (product name: U Varnish S, manufactured by Ube Industries, Ltd.) was applied by ring coating on the outer surface of the polyimide tube to form a coating film that covered the outer surface of the polyimide tube that was not covered with the conductive layer and the surface of the conductive layer. The coating film was then baked at a temperature of 200° C. for 30 minutes and further heated at a temperature of 400° C. for 30 minutes to form a polyimide film (resin layer 20e) with 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 polyimide film so that the dry weight was 20 mg, and after the solvent was dried, a baking treatment was performed for 30 minutes in an electric furnace set at 160°C.
A silicone rubber composition layer having a thickness of 250 μm was formed on this primer by ring coating, and primary crosslinking was carried out at 160° C. for 1 minute, followed by secondary crosslinking at 200° C. for 30 minutes to form an elastic layer.

The silicone rubber composition used was as follows:
As component (a), an organopolysiloxane having an alkenyl group was prepared. The component (a) 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.) was mixed and kneaded as component (d) thermally conductive filler into this addition-curing silicone rubber stock solution at a volume ratio of 45% based on the elastic layer, and an addition-curing silicone rubber composition having a Japan Industrial Standards (JIS) K6253-3:2023 (Type A durometer hardness) of 10° after curing was obtained.

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

[Example 2]
A fixing belt was produced in the same manner as in Example 1, except that the thickness of the conductive layer was 3 μm.
[Examples 3 to 4]
A fixing belt was produced in the same manner as in Example 1, except that the baking temperature for forming the conductive layer was changed to the temperature shown in Table 1.

[Example 5]
The resin layer was made of a polyamideimide solution (Viromax HR-16NN, manufactured by Toyobo Co., Ltd.), which was applied to the entire surface by ring coating and then baked at 200° C. for 30 minutes to form a resin layer with a thickness of 40 μm. Except for this, the fixing belt was manufactured in the same manner as in Example 1.

[Examples 6 to 7]
A fixing rotor was produced in the same manner as in Example 5, except that the baking temperature for forming the conductive layer was changed as shown in Table 1.

[Comparative Example 1]
A fixing rotor was produced in the same manner as in Example 1, except that the conductive layer 20b was formed by silver plating.
The conductive layer 20b was formed by silver plating in the following manner.
A cylindrical polyimide film was prepared, and a ring-shaped masking material was placed on the surface of the film. Then, a silver potassium cyanide bath was used as the silver plating bath, and plating was performed. The pH of the plating bath was kept at 8 to 9, and the temperature of the plating bath was kept at 50°C to 70°C. After being removed from the plating bath, the masking material was removed through a washing process, and a base layer on which a conductive layer having a thickness of 2.0 μm was formed was obtained.

[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 120°C.

[Comparative Example 3]
A fixing rotor was produced in the same manner as in Example 1, except that the material of the conductive layer 20b was copper, and the conductive layer was fired under a nitrogen atmosphere. The volume resistivity of the obtained conductive layer was 7.5×10 ⁻⁷ Ω·m, and when an image evaluation was carried out using an actual machine, insufficient heat generation occurred, resulting in poor image quality. This is believed to be due to the oxidation of copper progressing during the formation of the resin layer, which increased the volume resistivity of the conductive layer.

(Cross-section observation of conductive layer and image processing)
Samples each having a length of 5 mm, a width of 5 mm, and a thickness equal to the entire thickness of the fixing belt were taken from 20 random locations 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 a cross section along the circumferential direction of the fixing belt 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 backscattered electron image mode at 20,000 times magnification, and the backscattered electron image acquisition conditions were an acceleration voltage of 3.0 kV and a working distance of 3 mm.
The obtained cross-sectional image was subjected to binarization processing so that the crystal grains were displayed in white and the non-crystal grains were displayed in black.
The Ohtsu method described in "6" was used.
Specifically, the backscattered electron image was first read using image analysis software (ImageProPlus, MediaCybernetics), and an image was cut out at an arbitrary location within a range of 0.5 μm×0.5 μm to determine the luminance distribution of this image. Next, from the obtained luminance distribution, a binary image was obtained that could distinguish between areas corresponding to silver crystals and other areas based on the above-mentioned Otsu method.

(Calculation of porosity)
In the binarized image obtained by the above procedure, the silver crystals are shown as white areas. The porosity was calculated by calculating the area that these crystals occupy in the image.
Specifically, the number of pixels in the binarized image occupied by the area corresponding to the silver crystals was determined, and the area occupied by the crystal grains was calculated by multiplying this number of pixels by the area of one pixel (0.15×0.15=0.0225 μm ² ).
The porosity indicates the proportion of space not occupied by crystal particles in the conductive layer, and was calculated as follows using the area occupied by the crystal particles calculated above.
Porosity={area of binarized image (0.5×0.5 (μm ² ))−area occupied by crystal grains (μm ² )}÷area of binarized image (0.5×0.5 (μm ² ))×100
The arithmetic average value of the porosity calculated from the 20 samples by the above procedure was taken as the porosity of the conductive layer.

(Measurement of silver purity in conductive layer)
The conductive layer exposed on the polished surface of the sample was subjected to elemental analysis using an EDS mounted on the scanning electron microscope "JSM-F100" at an acceleration voltage of 5 to 15 kV and a magnification of 4000 times. The elemental analysis was performed at three arbitrary points on the cross section of the conductive layer 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 each of the cross-sectional images of the 20 samples was determined as the silver purity of the conductive layer of the fixing belt related to the observation target.

(Evaluation: Compressive elastic modulus)
<Conductive Layer>
The compressive elastic modulus of the conductive layer was measured by the following method.
First, the surface layer and the elastic layer were peeled off from the fixing rotor, and the laminate of the base layer, the conductive layer, and the resin layer was taken out. Next, a polyimide coating remover (e-Solv 21KZE-100, manufactured by Kaneko Chemical Co., Ltd.) was applied to the surface of the resin layer, and the resin layer was heated at 40° C. for 10 minutes.
After that, the substrate was cooled to room temperature (25° C.), washed with pure water, and dried to remove the resin layer, thereby exposing the conductive layer on the opposite side to the surface facing the substrate. The compressive modulus of the exposed conductive layer was measured using a Berkovich type indenter with a microindentation hardness tester (product name: Nanoindenter G200, manufactured by Agilent Technologies).
The measurement area was determined by pressing an indenter into the thickness direction from the first surface of the conductive layer opposite the surface facing the base layer to a depth of 1 μm, and calculating the average value of the compressive elastic modulus at each depth position measured in a region of 10 to 20% of the depth, i.e., a region of 0.1 μm to 0.2 μm from the surface, to calculate the average elastic modulus in this region. The measurement was performed in an environment with a temperature of 25° C. and a relative humidity of 50%. The results are shown in Table 1.

<Substrate>
The compressive elastic modulus of the substrate was measured by the following method.
The compressive modulus of the base material of the fixing rotor was measured using a Berkovich type indenter with a microindentation hardness tester (product name: Nanoindenter G200, manufactured by Agilent Technologies) on the surface opposite to the surface on which the conductive layer was formed. The measurement method and conditions were the same as those for measuring the compressive modulus of the conductive layer.

(Evaluation: actual machine durability test)
For the fixing rotating members of Examples 1 to 7 and Comparative Examples 1 to 3, a paper feed durability test was carried out under the following conditions.
The fixing rotors according to Examples 1 to 7 and Comparative Examples 1 to 3 were incorporated into a fixing device, and the fixing device was mounted on a laser printer (product name: Satera LBP961Ci, manufactured by Canon Inc.). In an environment with an air temperature of 15°C and a humidity of 10%, 2 million sheets of A4-sized plain paper were passed through the printer without forming an image on the plain paper. Then, the presence or absence of deformation of the base material of the fixing belt at the portion where the end of the paper abutted was observed every 10,000 sheets of paper. The above-mentioned laser printer was modified so that the pressure roller and the fixing belt rotated at high speed (linear speed 400 mm/s).
The recording material used for the paper feed was a color laser NPI high-quality heavyweight (A4 size 128 g/ ^m2 , thickness 148 μm, Canon Marketing Japan). After 2 million sheets had been fed, one solid cyan image was formed on the recording material. The solid image obtained was visually observed. The observation results were evaluated according to the following criteria.

Rank A: No deformation was observed in the base material of the fixing belt even when the number of sheets passed reached 2,000,000. Also, no fixing unevenness was observed in the solid image.
Rank B: When the number of sheets passed reached 2,000,000, deformation was observed at the position of the fixing belt base material corresponding to the edge of the paper in contact with the base material. On the other hand, no fixing unevenness due to the deformation was observed in the solid image.
Rank C: Before the number of sheets passed reached 2,000,000, deformation was observed at the position of the fixing belt base material corresponding to the edge of the paper in contact with the base material. Furthermore, fixing unevenness due to the deformation was observed in the solid image.

The evaluation results are shown in Table 1. In the remarks column of the results of the actual machine evaluation of Comparative Examples 1 to 3, the number of sheets at which deformation was first observed on the observed surface of the substrate is recorded.

In Table 1, PI refers to polyimide and PAI refers to polyamideimide.
The "thickness" of the conductive layer refers to the maximum thickness of the conductive layer.

From the results in Table 1, it can be seen that by suppressing the compressive elastic modulus of the conductive layer low, there is no buckling deformation even when used for a long time as a fixing rotating body, and it is highly durable. It can also be seen that in Examples 1 to 7, the volume resistivity of the conductive layer is low enough to maintain conductivity, and the occurrence of image defects can be suppressed.
The higher the porosity, the lower the compressive modulus of the conductive layer. In addition, when silver nanoink is used as the metal species, it is clear that the porosity can be adjusted by the baking temperature of the conductive layer. The higher the baking temperature, the higher the porosity and the lower the compressive modulus.

The present disclosure includes the following configurations and methods.
(Configuration 1)
A fixing rotor,
The fixing rotor is
A cylindrical substrate containing at least 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 is
The groove extends in a circumferential direction of the outer peripheral surface of the substrate, and
Contains silver,
the volume resistivity of the conductive layer is 1.0×10 ⁻⁸ to 8.0×10 ⁻⁸ Ω·m;
The fixing rotor is characterized in that the average compressive elastic modulus in a thickness region of the conductive layer at a depth of 0.1 to 0.2 μm from the first surface, which is measured by bringing an indenter into contact with the first surface of the conductive layer opposite to the surface facing the substrate, is 8 to 30 GPa.
(Configuration 2)
2. The fixing rotating member according to claim 1, wherein the resin contained in the base material is at least one selected from the group consisting of polyimide and polyamideimide.
(Configuration 3)
The fixing rotating member according to the first or second aspect of the present invention, wherein the conductive layer has a maximum thickness Te of 4 μm or less. (Configuration 4)
The fixing rotating member according to any one of configurations 1 to 3, wherein the conductive layer has voids when observed in cross section in the circumferential direction.
(Configuration 5)
5. The fixing rotatable member according to configuration 4, wherein, in a cross-sectional observation of the conductive layer in a circumferential direction thereof using a scanning electron microscope, the conductive layer has a porosity of 15 to 50%.
(Configuration 6)
The fixing rotating member according to any one of configurations 1 to 5, wherein the conductive layer is made substantially of silver.
(Configuration 7)
The fixing rotating member according to any one of configurations 1 to 6, wherein the conductive layer is a sintered body of silver nanoparticles.
(Configuration 8)
The fixing rotor according to any one of configurations 1 to 7, wherein the conductive layer includes a plurality of conductive regions in a direction perpendicular to a circumferential direction of the fixing rotor, and the plurality of conductive regions are electrically independent from each other.
(Configuration 9)
The conductive layer has an average compressive elastic modulus of
The fixing rotor according to any one of configurations 1 to 8, wherein the compressive elastic modulus is 6 times or less than the average value of a compressive elastic modulus in a thickness region of the substrate at a depth of 0.1 to 0.2 μm from the first surface of the substrate, the compressive elastic modulus being measured by contacting an indenter with the first surface of the substrate opposite to the surface on which the conductive layer is formed.
(Configuration 10)
10. The fixing rotating member according to any one of claims 1 to 9, wherein the base material has an average compressive elastic modulus of 2.5 to 6.0 GPa.
(Configuration 11)
11. The fixing rotating member according to any one of configurations 1 to 10, wherein the resin contained in the resin layer is at least one selected from the group consisting of polyimide and polyamideimide.
(Configuration 12)
The fixing rotating member according to any one of configurations 1 to 11, wherein the resin contained in the base material is polyimide, and the resin contained in the resin layer is polyamideimide. (Configuration 13)
A fixing rotating body according to any one of configurations 1 to 12,
and an induction heating device for heating the fixing rotatable body by induction heating.
(Configuration 14)
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, for inducing magnetic lines of the alternating magnetic field;
The magnetic core is made of a ferromagnetic material,
The fixing device described in configuration 13, wherein the conductive layer of the fixing rotor is heated by an induced current induced by magnetic field lines that emerge 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 15)
1. An electrophotographic image forming apparatus, comprising:
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
15. An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to configuration 13 or 14.
(Method 16)
A method for producing a fixing rotating body according to any one of configurations 1 to 12, comprising the steps of:
(i) obtaining the substrate;
(ii) applying a silver nanoparticle ink to the outer peripheral surface of the substrate obtained in step (i) and baking the ink to obtain a conductive layer;
(iii) applying a resin material onto the conductive layer obtained in the step (ii) and baking the applied resin material to obtain a resin layer;
A method for manufacturing a fixing rotating body, comprising the steps of:

1 Image forming device, 15 Fixing device, 20 Fixing rotor, 20a Base material, 20b Conductive layer, 20c Elastic layer, 20d Surface layer, 20e Resin layer, 20f Adhesive layer, 21 Pressure roller

Claims (16)

A fixing rotor,
The fixing rotor is
A cylindrical substrate containing at least 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 is
The groove extends in a circumferential direction of the outer peripheral surface of the substrate, and
Contains silver,
the volume resistivity of the conductive layer is 1.0×10 ⁻⁸ to 8.0×10 ⁻⁸ Ω·m;
The fixing rotor is characterized in that the average compressive elastic modulus in a thickness region of the conductive layer at a depth of 0.1 to 0.2 μm from the first surface, which is measured by bringing an indenter into contact with the first surface of the conductive layer opposite to the surface facing the substrate, is 8 to 30 GPa. The fixing rotor according to claim 1, wherein the resin contained in the base material is at least one selected from the group consisting of polyimide and polyamideimide. The fixing rotor according to claim 1, wherein the maximum thickness Te of the conductive layer is 4 μm or less. The fixing rotor according to claim 1, wherein the conductive layer has voids when observed in cross section in the circumferential direction. The fixing rotor according to claim 4, wherein the porosity of the conductive layer is 15 to 50% when a cross-section of the conductive layer in the circumferential direction is observed using a scanning electron microscope. The fixing rotor of claim 1, wherein the conductive layer is substantially made of silver. The fixing rotor according to claim 1, wherein the conductive layer is a sintered body of silver nanoparticles. The fixing rotor according to claim 1, wherein the conductive layer includes a plurality of conductive regions in a direction perpendicular to the circumferential direction of the fixing rotor, and the plurality of conductive regions are electrically independent of each other. The conductive layer has an average compressive elastic modulus of
2. The fixing rotor according to claim 1, wherein the compressive elastic modulus is 6 times or less of the average value of a compressive elastic modulus in a thickness region of the substrate at a depth of 0.1 to 0.2 μm from the first surface of the substrate, the compressive elastic modulus being measured by contacting an indenter with the first surface of the substrate opposite to the surface on which the conductive layer is formed. The fixing rotor according to claim 1, wherein the average compressive elastic modulus of the substrate is 2.5 to 6.0 GPa. The fixing rotor according to claim 1, wherein the resin contained in the resin layer is at least one selected from the group consisting of polyimide and polyamideimide. The fixing rotor according to claim 1, wherein the resin contained in the base material is polyimide, and the resin contained in the resin layer is polyamideimide. A fixing rotating body according to any one of claims 1 to 12,
and an induction heating device for heating 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, for inducing magnetic lines of the alternating magnetic field;
The magnetic core is made of a ferromagnetic material,
14. The fixing device according to claim 13, wherein the conductive layer of the fixing rotor is heated 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:
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
14. An electrophotographic image forming apparatus, wherein the fixing device is the fixing device according to claim 13. A method for manufacturing the fixing rotating body according to any one of claims 1 to 12, comprising the steps of:
(i) obtaining the substrate;
(ii) applying a silver nanoparticle ink to the outer peripheral surface of the substrate obtained in step (i) and baking the ink to obtain a conductive layer;
(iii) applying a resin material onto the conductive layer obtained in the step (ii) and baking the applied resin material to obtain a resin layer;
A method for manufacturing a fixing rotating body, comprising the steps of:

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