CN117930609A

CN117930609A - Rotary member for fixing

Info

Publication number: CN117930609A
Application number: CN202311399345.4A
Authority: CN
Inventors: 冈野宪; 鹤谷贵明; 前田松崇; 相马真琴; 笠井奈绪子
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2022-10-26
Filing date: 2023-10-26
Publication date: 2024-04-26

Abstract

The present invention relates to a fixing rotary member. A rotary member for fixing, comprising: a cylindrical base member containing at least a resin; a conductive layer on the base member; and a resin layer on a surface of the conductive layer, the surface being opposite to a surface facing the base member, the conductive layer extending in a circumferential direction of an outer peripheral surface of the base member, the conductive layer including silver, a volume resistivity of the conductive layer being 1.0×10 ^‑8 to 8.0×10 ^‑8 Ω·m, and a compressive elastic modulus of the conductive layer being 8 to 30GPa, the elastic modulus being measured by bringing a indenter into contact with a first surface of the conductive layer opposite to the surface facing the base member, and the elastic modulus being an average value of elastic moduli of a thickness region of 0.1 to 0.2 μm from the first surface of the conductive layer.

Description

Rotary member for fixing

Technical Field

The present disclosure relates to a rotary member for fixing used in a fixing device of an electrophotographic image forming apparatus such as an electrophotographic copying machine or a printer.

Background

A general fixing device mounted in an electrophotographic image forming apparatus such as an electrophotographic copying machine or a printer fixes a toner image on a recording material by heating while conveying the recording material carrying an unfixed toner image at a nip portion formed by a rotary member for fixing to be heated and a pressure roller in contact therewith.

An electromagnetic induction heating type fixing device has been developed and put into practical use, in which a rotary member for fixing has a conductive layer, and the conductive layer can be directly heated. The electromagnetic induction heating type fixing device has the advantage of short preheating time.

The conductive layer is required to have conductivity and durability against repeated strain under heating, and in japanese patent application laid-open No.2021-51136, a fixing member having a conductive layer formed by copper plating is disclosed.

Disclosure of Invention

At least one aspect of the present disclosure is directed to providing a rotary member for fixing having high conductivity and excellent durability. At least one aspect of the present disclosure is directed to providing a fixing device that facilitates stable formation of electrophotographic images having high quality. Further, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus capable of stably forming an electrophotographic image having high quality.

According to at least one aspect of the present disclosure, there is provided a rotary member for fixing, including: a cylindrical base member containing at least a resin; a conductive layer on the base member; and a resin layer on a surface of the conductive layer, the surface being opposite to a surface facing the base member, the conductive layer extending in a circumferential direction of an outer peripheral surface of the base member, the conductive layer including silver, a volume resistivity of the conductive layer being 1.0×10 ^-8 to 8.0×10 ^-8 Ω·m, and a compressive elastic modulus of the conductive layer being 8 to 30GPa, the compressive elastic modulus being measured by bringing a indenter into contact with a first surface of the conductive layer opposite to the surface facing the base member, and the compressive elastic modulus being an average of compressive elastic moduli in a thickness region of 0.1 to 0.2 μm from the first surface of the conductive layer.

Further, at least one aspect of the present disclosure is directed to a fixing device including the fixing rotating member and an induction heating device for heating the fixing rotating member by induction heating.

Further, at least one aspect of the present disclosure is directed to an electrophotographic image forming apparatus, including:

An image bearing member that bears a toner image;

a transfer device that transfers the toner image to a recording material; and

A fixing device that fixes the transferred toner image onto the recording material,

Wherein the fixing device is the fixing device.

Further, at least one aspect of the present disclosure is directed to a method of manufacturing the above-described rotary member for fixation, including:

(i) A step of obtaining a base member;

(ii) A step of obtaining a conductive layer by applying silver nanoparticle ink to the outer peripheral surface of the base member obtained in the step (i) and firing; and

(Iii) A step of obtaining a resin layer by applying a resin material to the conductive layer obtained in the step (ii) and firing.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

FIG. 1 is a cross-sectional image of a conductive layer (a photograph in place of the drawing);

FIG. 2 is a schematic view of an electrophotographic image forming apparatus according to an embodiment;

Fig. 3 is a schematic diagram showing a cross-sectional configuration of a fixing device according to an embodiment;

Fig. 4 is a perspective view showing a sectional configuration of a fixing device according to an embodiment;

fig. 5 is a schematic diagram of a magnetic core and an exciting coil of a fixing device according to an embodiment;

Fig. 6 is a diagram showing a magnetic field generated when a current flows through an exciting coil according to an embodiment;

Fig. 7 is a sectional configuration view of a rotary member for fixing according to the embodiment; and

Fig. 8A to 8C show schematic diagrams illustrating a mechanism of forming pores penetrating through the conductive layer of the rotary member for fixing according to the embodiment in the thickness direction.

Detailed Description

In the present disclosure, the expression "from XX to YY" or "XX to YY" representing a numerical range is meant to include the numerical ranges of the lower limit and the upper limit as endpoints unless otherwise indicated. Further, when numerical ranges are described in a stepwise manner, the upper limit and the lower limit of each numerical range may be arbitrarily combined. Further, in the present disclosure, for example, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any of a combination of XX, YY, ZZ, XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, and a combination of XX, YY, and ZZ.

In recent years, as the speed of printers increases, further improvement in the durability of the fixing member is demanded. In the fixing member, when sheets of different sizes are loaded, since pressure is locally applied to the end of the sheet, that is, a so-called sheet edge, durability against a partial compression load is required. In particular, in the constitution in which a plurality of conductive layers are formed on the outer peripheral surface of the base member layer as disclosed in japanese patent application laid-open No.2021-51136, when the paper edge is subjected to repeated compression deformation, if the compressive strain difference between the conductive layer and the resin layer increases, stress concentration increases at the interface between the resin layer and the conductive layer, and there is a concern that buckling or the like occurs. That is, it has been found that if the difference in rigidity between the conductive layer and the base member layer or between the conductive layer and the resin layer increases, durability problems are caused where cracks occur along the conductive layer.

Specific configurations of a fixing rotary member having a conductive layer, a fixing device produced using the fixing rotary member, and an electrophotographic image forming apparatus according to the present disclosure will be described in detail below.

However, the size, materials, shape, and relative arrangement of the components described in this aspect should be appropriately changed according to the constitution and various conditions of the member to which the present disclosure is applied. That is, the scope of the present disclosure is not intended to be limited in the following respects. In addition, in the following description, the components having the same functions will be denoted by the same reference numerals in the drawings, and the description thereof may be omitted.

Electrophotographic image forming apparatus

An electrophotographic image forming apparatus (hereinafter simply referred to as an "image forming apparatus") includes an image bearing member that bears a toner image, a transfer device that transfers the toner image to a recording material, and a fixing device that fixes the transferred toner image to the recording material.

Fig. 2 is a transverse sectional view showing the overall constitution of a color laser beam printer (hereinafter referred to as a printer) 1 as an example of an image forming apparatus on which a fixing device (image heating device) 15 according to an embodiment is mounted.

The cartridge 2 is accommodated in the lower portion of the printer 1 so that it can be pulled out. The cassette 2 loads and accommodates a sheet P as a recording material. The sheets P in the cassette 2 are fed to the registration rollers 4 while being separated one by the separation rollers 3. Here, as the sheet P of the recording material, various sheets having different sizes and materials, for example, paper such as plain paper and thick paper, surface-treated sheets such as plastic film, cloth, coated paper, and the like, and sheets of special shapes such as envelope and index paper, and the like, may be used.

The printer 1 includes, as image forming means, image forming units 5 in which image forming units 5Y, 5M, 5C, and 5K corresponding to yellow, magenta, cyan, and black, respectively, are arranged in a horizontal arrangement. In the image forming unit 5Y, a photosensitive drum 6Y as an image bearing member (electrophotographic photoreceptor) and a charging roller 7Y as a charging means for uniformly charging the surface of the photosensitive drum 6Y are provided. In addition, a scanner unit 8 is provided below the image forming unit 5. The scanner unit 8 emits an on/off modulated laser beam corresponding to a digital image signal input from an external device such as a computer (not shown) and generated by an image processing means based on image information, and forms an electrostatic latent image on the photosensitive drum 6Y.

Further, the image forming unit 5Y includes a developing roller 9Y and a primary transfer unit 11Y, the developing roller 9Y being a developing means for developing a toner image (toner picture) by attaching toner to an electrostatic latent image on the photosensitive drum 6Y, the primary transfer unit 11Y transferring the toner image on the photosensitive drum 6Y to the intermediate transfer belt 10.

The toner images formed by the other image forming units 5M, 5C, and 5K in the same process are also transferred to the toner image on the intermediate transfer belt 10, and the intermediate transfer belt 10 has transferred the toner image by the primary transfer unit 11Y.

Thus, a full-color toner image is formed on the intermediate transfer belt 10. The 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 image onto a recording material.

Then, the toner image transferred onto the sheet P (recording material) passes through the fixing device 15 and is fixed as a fixed image. In addition, the sheet P passes through the discharge conveying unit 13 and is discharged to and loaded on the loading unit 14.

Here, the image forming unit 5 is one example of image forming means. Although the primary transfer unit 11Y and the secondary transfer unit 12 are exemplified as fixing devices, the fixing devices may be, for example, direct transfer type fixing devices that directly transfer the toner image from the image bearing member to the sheet P. Further, the image forming apparatus may have a monochrome type configuration using only one color of toner.

Fixing device

The fixing device 15 of the present embodiment is an induction heating type fixing device (image heating device) that heats a fixing rotary member 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. Here, in fig. 3 and 4, a housing or the like of the fixing device 15 is omitted. In the following description, regarding the members constituting the fixing device 15, the longitudinal direction X1 is a direction orthogonal to the conveying direction of the recording material and the thickness direction of the recording material, that is, the rotation axis direction of the fixing rotary member 20.

The fixing device 15 includes a fixing rotary member 20, a film guide 25, a pressing roller 21, a pressing holder 22, a magnetic core 26, an exciting coil 27, a thermistor 40, and a current sensor 30. The fixing device 15 heats the recording material on which the image is formed, and fixes the image onto the recording material. The fixing rotary member 20 is a fixing rotary member of the present embodiment, and the pressing roller 21 is an opposing member of the present embodiment. The exciting coil 27 functions as a magnetic field generating means of the present embodiment. Details of the fixing rotary member will be described below.

The fixing rotary member 20 includes a base member 20a, a conductive layer 20b on an outer surface of the base member 20a, and a resin layer 20e on a surface of the conductive layer on an opposite side to a side facing the base member.

In a cross-sectional view in a longitudinal direction perpendicular to the circumferential direction of the fixing rotary member, that is, in a direction along the rotation axis of the fixing rotary member, the conductive layer 20b may be constituted by a plurality of conductive regions 201, as shown in fig. 4. Each conductive region extends in a circumferential direction of the fixing rotary member. That is, the conductive layer 20b may include a conductive region having a ring shape, which is electrically independent. Here, "electrically independent" means that each conductive region can independently generate heat by electromagnetic induction. Each conductive region 201 preferably has a uniform width in the length direction X1.

The pressing roller 21 is an opposing member (pressing member) facing the fixing rotary member 20, and includes a core metal 21a and an elastic layer 21b concentrically integrally molded around the core metal in the shape of a roller and coated, and a release layer 21c is provided on the surface layer. The elastic layer 21b is preferably made of a material having excellent heat resistance, such as silicone rubber, fluororubber, or fluorosilicone rubber. Accordingly, both ends of the core metal 21a in the length direction are held rotatably via conductive bearings and arranged between metal plates (not shown) on the chassis side of the fixing device.

In addition, as shown in fig. 4, when the pressing springs 24a and 24b are compressively installed between both ends of the pressing support 22 in the longitudinal direction and the spring receiving members 23a and 23b on the device chassis side, a downward force is applied to the pressing support 22.

Here, in the fixing device 15 of the present embodiment, a pressing force of about 100N to 300N (about 10kgf to about 30 kgf) in total pressure is applied. Accordingly, the lower surface of the film guide 25 and the upper surface of the pressing roller 21 made of a heat-resistant resin such as polyphenylene sulfide (PPS) are pressed against each other with the fixing rotary member 20 as a cylindrical rotary member therebetween to form the fixing nip portion N having a predetermined width. The film guide 25 functions as a nip forming member that forms a nip for nipping and conveying a recording material bearing a toner image via the fixing rotary member 20 together with the pressing roller 21.

The pressing roller 21 is driven by a driving means (not shown) to rotate clockwise, and applies a counterclockwise rotational force to the fixing rotating member 20 according to friction with the outer surface of the fixing rotating member 20. Therefore, the fixing rotating member 20 rotates while sliding on the film guide 25.

Fig. 5 is a schematic diagram of the magnetic core 26 and the exciting coil 27 shown in fig. 3, and shows the fixing rotary member 20 with a broken line in order to explain the positional relationship with the fixing rotary member 20. The induction heating device in the induction heating type fixing device that heats the fixing rotating member 20 according to electromagnetic induction may include a magnetic core 26 and an exciting coil 27.

The exciting coil 27 is arranged inside the fixing rotary member 20. The exciting coil 27 has a spiral portion whose spiral axis is substantially parallel to a direction along the rotation axis of the fixing rotation member 20, and generates an alternating magnetic field that causes the conductive layer 20b to generate heat by electromagnetic induction. "substantially parallel" means not only that the two axes are perfectly parallel, but also that a slight deviation is allowed in the extent to which the conductive layer is allowed to generate heat by electromagnetic induction.

The magnetic core 26 is provided in the spiral-shaped portion, extends in the rotation axis direction of the fixing rotation member 20, and does not form a ring outside the fixing rotation member 20. The magnetic core 26 induces magnetic field lines of the alternating magnetic field.

In fig. 5, the magnetic core 26 is inserted into a hollow portion of the fixing rotary member 20 that is a cylindrical rotary member. In addition, the exciting coil 27 is spirally wound around the outer periphery of the magnetic core 26 and extends in the length direction. The magnetic core 26 has a cylindrical shape, and is fixed by fixing means (not shown) such that it is located substantially at the center of the fixing rotary member 20 in a cross section viewed in the length direction (see fig. 3).

The magnetic core 26 provided in the exciting coil 27 has a function of inducing magnetic force lines (magnetic fluxes) of the alternating magnetic field generated from the exciting coil 27 inward from the conductive layer 20b of the fixing rotary member 20 and forming magnetic force line paths (magnetic circuits). The material of the magnetic core 26 is ferromagnetic. The material of the magnetic core 26 as the ferromagnetic body is preferably a material having a small hysteresis loss and a high specific magnetic permeability, for example, at least one kind of soft magnetic material having a high magnetic permeability selected from the group consisting of sintered ferrite and ferrite resin.

Preferably, the following shape is formed: more than 70% of the magnetic flux is emitted from one longitudinal end of the magnetic core 26 in the rotation axis direction, passes through the outside of 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 may be any shape as long as it can be accommodated in the hollow portion of the fixing rotary member 20, and although it is not necessarily circular, a shape that allows a cross-sectional area as large as possible is preferable. In this embodiment, the magnetic core 26 has a diameter of 10mm and a length of 280mm in the length direction.

The exciting coil 27 is formed by spirally winding a copper wire (single wire) coated with heat-resistant polyamideimide and having a diameter of 1 to 2mm around the magnetic core 26. The exciting coil 27 is wound around the outer periphery of the magnetic core 26 in a direction intersecting the rotation axis direction of the fixing rotation member 20. Therefore, when a high-frequency alternating current flows through the exciting coil 27, an alternating magnetic field is generated in a direction parallel to the rotation axis direction of the fixing rotation member 20, and an induced current (circulating current) flows through each heat generating ring 201 of the conductive layer 20b of the fixing rotation member 20 and generates heat according to a principle to be described below.

As shown in fig. 3 and 4, the thermistor 40 as a temperature detection means for detecting the temperature of the fixing rotary member 20 includes 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 rotary member 20. A thermistor element 40b as a temperature detecting element is mounted on the tip of the spring plate 40 a. The surface of the thermistor element 40b is covered with a polyimide tape 50 μm thick in order to ensure electrical insulation.

The thermistor 40 is fixed to the film guide 25 and is mounted at a substantially central position in the longitudinal direction of the fixing rotary member 20. The thermistor element 40b is elastically pressed against the inner surface of the fixing rotary member 20 according to the spring of the spring plate 40a, and is held in a contact state. Here, the thermistor 40 may be disposed on the outer peripheral side of the rotary member 20 for fixation.

The current sensor 30 constituting conduction monitoring means for monitoring conduction of the conductive layer 20b in the circumferential direction is arranged at the same position as the thermistor 40 in the length direction of the fixing device 15. That is, the current sensor 30 monitors the conduction state of the heat generating ring 201 at the position where the thermistor element 40b contacts among the plurality of heat generating rings 201 constituting the heat generating pattern of the fixing rotary member 20.

Principle of heating

The heating principle of the fixing rotary member 20 in the induction heating type fixing device 15 will be described.

Fig. 6 is a conceptual diagram showing a magnetic field generated when a current flows through the exciting coil 27 in the direction of arrow I0. The exciting coil 27 is wound around the outer circumference of the magnetic core 26 inserted into the fixing rotary member 20, and functions as a magnetic field generating means in which an alternating magnetic field is generated in the rotation axis direction of the fixing rotary member 20 and an induced current I is generated in the circumferential direction of the fixing rotary member 20 when an alternating current flows.

Further, the magnetic core 26 functions as a member that induces magnetic force lines B (broken lines in fig. 6) generated by the exciting coil 27 and forms a magnetic circuit.

In a general induction heating type fixing device, magnetic force lines penetrate through a conductive layer and generate eddy currents. On the other hand, in the present embodiment, the magnetic force lines B are wound around the outside of the fixing rotary member. That is, the conductive layer 20b is mainly heated by an induction current induced by magnetic force lines, which are emitted from one longitudinal end portion of the magnetic core 26, pass through the outside of the conductive layer 20b, and return to the other longitudinal end portion of the magnetic core 26. Therefore, even if the thickness of the conductive layer is made thin, for example, 4 μm or less, heat can be effectively generated.

When the alternating magnetic field is generated by the exciting coil 27, the induced current I flows through each heat generating ring 201 of the conductive layer 20b of the fixing rotary member 20 according to faraday's law. Faraday's law states that "when the magnetic field in a circuit changes, an induced electromotive force is generated that causes a current to flow in the circuit, and the induced electromotive force is proportional to the change in magnetic flux vertically penetrating the circuit with time.

Regarding the heat generating ring 201c located at the center portion of the magnetic core 26 shown in fig. 6 in the longitudinal direction, an induced current I flowing through the heat generating ring 201c when a high-frequency alternating current flows through the exciting coil 27 is considered. When a high-frequency alternating current flows, an alternating magnetic field is generated inside the magnetic core 26. In this case, according to the following mathematical expression 1, the induced electromotive force applied to the heat generating ring 201c is proportional to the change over time of the magnetic flux vertically penetrating the inside of the heat generating ring 201 c.

V: induced electromotive force

N: turns of coil

ΔΦ/Δt: variation of magnetic flux vertically penetrating the circuit (heat generating ring 201 c) within a minute time Δt

Due to this induced electromotive force V, an induced current I, which is a circulating current circulating in the heat generating ring 201c, flows, and the heat generating ring 201c generates heat due to joule heat generated by the induced current I.

However, when the heat generation ring 201c is turned off, the induced current I does not flow, and the heat generation ring 201c does not generate heat.

(1) Schematic constitution of rotating Member for fixing

Details of the rotary member for fixing of the present embodiment will be described with reference to the drawings.

The fixing rotary member according to an aspect of the present disclosure may be, for example, a rotatable member, such as an endless belt shape.

Fig. 7 is a sectional view of the fixing rotary member in the circumferential direction. The rotary member for fixing includes a cylindrical base member 20a containing at least a resin, a conductive layer 20b on the base member 20a, and a resin layer 20e on a surface of the conductive layer on the opposite side to the side facing the base member. 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, as needed.

(2) Base member

The material of the base member 20a is not particularly limited as long as it is a layer containing at least a resin. That is, the base member 20a includes a resin. When the belt is used in an electromagnetic induction type fixing device, the base member 20a may be a layer that maintains high strength while the conductive layer is heated with little change in physical properties. Therefore, the base member 20a preferably includes a heat-resistant resin as a main component, and is preferably formed of a heat-resistant resin. The heat-resistant resin is, for example, a resin that does not melt or decompose at a temperature lower than 200 ℃ (preferably lower than 250 ℃).

The resin contained in the base member 20a (preferably, the resin constituting the base member) is preferably at least one selected from the group consisting of Polyimide (PI), polyamideimide (PAI), modified polyimide, and modified polyamideimide. At least one selected from the group consisting of polyimide and polyamideimide is more preferable. Among them, polyimide is particularly preferable. Here, in the present disclosure, the main component is the component whose content is largest among the components constituting the object (here, the base member).

Here, examples of the modification of the modified polyimide and modified polyamideimide include siloxane modification, carbonate modification, fluorine modification, polyurethane modification, triazine modification, and phenol modification.

In the fixing rotary member, the material of the base member 20a can be analyzed according to the following procedure.

A sample having a square 10mm square is cut from the fixing rotary member, and if an elastic layer or a surface layer is provided, it is removed by a razor, a solvent or the like. The material may be confirmed when total reflection (ATR) measurements are performed on the obtained samples using an infrared spectroscopic analysis device (FT-IR) (e.g., product name: front FT IR, commercially available from PerkinElmer co., ltd.).

Further, the material of the resin layer to be described below may be analyzed by the same method as described above.

In order to improve heat insulation and strength, a filler may be added to the base member 20 a.

The shape of the base member may be appropriately selected according to the shape of the rotary member for fixation, and various shapes such as an endless belt shape, a hollow cylindrical shape, and a film shape may be used.

The thickness of the base member 20a is, for example, preferably 10 to 100 μm, more preferably 20 to 60 μm. When the thickness of the base member 20a is set within the above-described range, both strength and flexibility can be achieved at a high level.

Further, on the surface of the base member 20a on the opposite side to the side facing the conductive layer 20b, for example, a layer for preventing abrasion of the inner peripheral surface of the fixing belt when the inner peripheral surface of the fixing belt contacts other members or a layer for improving slidability with respect to the other members may be provided.

Here, in order to improve the adhesion and wettability with respect to the conductive layer 20b, the outer peripheral surface of the base member 20a may be subjected to roughening treatment such as sandblasting and modification treatment such as ultraviolet rays, plasma, chemical etching and the like.

(3) Conductive layer

The conductive layer 20b is a layer that extends in the circumferential direction of the outer peripheral surface of the base member and generates heat during current application. In the principle of generating heat by induction heating using the exciting coil, when an alternating current is supplied to the exciting coil disposed near the fixing rotary member, a magnetic field is induced, and due to the magnetic field, the induced current flows through the conductive layer 20b of the fixing rotary member and generates heat by joule heat.

The material of the conductive layer 20b is preferably silver because it has low volume resistivity and is not easily oxidized. The conductive layer 20b includes silver.

When the conductive layer 20b includes silver, the required conductivity of the conductive layer can be maintained, and occurrence of image defects can be prevented. Further, deterioration due to oxidation can be reduced, and durability can be improved. The conductive layer 20b may include a metal other than silver as long as the effect of the present disclosure is not impaired thereby. However, the purity of silver constituting at least a part of the conductive layer 20b is preferably 90 mass% or more, more preferably 99 mass% or more, and particularly preferably 99.9 mass% or more. The upper limit of the silver content is not particularly limited, but for example, the upper limit is 100 mass% or less.

In the rotary member for fixation, analysis of silver in the conductive layer can be performed, for example, according to the following procedure.

Twenty (20) samples each having a length of 5mm, a width of 5mm and a thickness equal to the total thickness of the fixing rotating member were collected from an arbitrary position on the fixing rotating member from the fixing rotating member. For the 20 samples obtained, the cross section of the rotary member for fixing in the circumferential direction was exposed with a cross section polisher (product name: SM09010, commercially available from JEOL ltd.). Subsequently, the exposed cross section of the conductive layer was observed under a Scanning Electron Microscope (SEM) (product name: JSM-F100, commercially available from JEOL ltd.) and energy dispersive X-ray spectroscopy (EDS) analysis was performed on the silver crystalline particles in the observed image. The observation condition was 20,000 times magnification, secondary electron image acquisition mode, EDS analysis condition was acceleration voltage 5.0kV, working distance 10mm. The spatial extent of the EDS analysis performed is determined and adjusted by the region designation such that only silver crystalline particles in the observed image are selected.

An image is taken from a sample and EDS analysis is performed at three locations in the image. The silver content at 60 positions in total among 20 samples was analyzed, and the arithmetic average thereof was calculated, so that the silver content in the rotary member for fixing could be measured.

The maximum thickness of the conductive layer 20b is preferably 4 μm or less. Within the above thickness range, the fixing rotary member may have appropriate flexibility, and the heat capacity may be reduced.

Further, when the maximum thickness is set to 4 μm or less, bending resistance can be further improved. As shown in fig. 3, the fixing rotary member 20 is driven to rotate while being pressed against the film guide 25 and the pressing roller 21. For each rotation, the fixing rotary member 20 is pressed and deformed at the fixed nip portion N and receives stress. It is preferable to design the conductive layer 20b of the fixing rotary member 20 so that fatigue fracture is not caused even if such repeated bending is continuously applied until the durable life of the fixing device is reached.

When the thickness of the conductive layer 20b is reduced, fatigue fracture resistance of the conductive layer 20b is significantly improved. This is because, when the conductive layer 20b is pressed and deformed along the shape of the curved surface of the film guide 25, the internal stress applied to the conductive layer 20b decreases as the conductive layer 20b becomes thinner. Further, when the thickness of the conductive layer is reduced, the time required for the conductive layer to sufficiently generate heat can be further shortened.

For the above reasons, the maximum thickness of the conductive layer 20b is preferably 4 μm or less.

The maximum thickness 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 for maintaining durability. The maximum thickness of the conductive layer is, for example, 1 to 4 μm, and particularly preferably in the range of 1 to 3 μm.

The maximum thickness of the conductive layer in the rotary member for fixation can be measured by the following method.

From the fixing rotating member, six samples each having a length of 5mm, a width of 5mm, and a thickness equal to the total thickness of the fixing rotating member were collected from any position on the fixing rotating member. For the six samples obtained, the cross section of the rotary member for fixing in the circumferential direction was exposed with a cross section polisher (product name: SM09010, commercially available from JEOL ltd.).

Subsequently, the exposed cross section of the conductive layer was observed under a Scanning Electron Microscope (SEM) (product name: JSM-F100, commercially available from JEOL Ltd.) having an acceleration voltage of 3kV, a working distance of 2.9mm, a magnification of 10,000 times to obtain an image having a width of 13 μm and a height of 10. Mu.m. Regarding the conductive layer in the obtained image, parallel lines were drawn at the position closest to the base member side and the position closest to the resin layer side opposite thereto, and the distance between them was taken as the thickness of the conductive layer in the image, and the arithmetic average of six samples was defined as the maximum thickness. Here, the parallel lines are drawn with reference to the surface of the base member opposite the conductive layer in the observation area.

The volume resistivity of the conductive layer is 1.0X10 ^-8 to 8.0X10 ^-8. OMEGA.m. When the volume resistivity of the conductive layer is set within the above range, the required conductivity of the conductive layer can be maintained, and occurrence of image defects can be prevented.

The volume resistivity of the conductive layer is preferably 2.0X10 ^-8 Ω·m or more, more preferably 2.5X10 ^-8 Ω·m or less. Further, 7.0X10. 10 ^-8 Ω·m or less is preferable, and 6.0X10. 10 ^-8 Ω·m or less is more preferable. For example, a range of 2.0X10 ^-8 to 7.0X10 ^-8. OMEGA.m and 2.0X10 ^-8 to 6.0X10 ^-8. OMEGA.m can be preferably exemplified.

The volume resistivity of the conductive layer may be controlled according to, for example, the material of the conductive layer, the manufacturing method of the conductive layer, and the like. In particular, when silver is used as a material of the conductive layer, the volume resistivity can be increased. In addition, in particular, for example, when the conductive layer is formed using silver nanoink, when the firing temperature of the coating layer of silver nanoink formed on the surface of the base member is high, a conductive layer having a low volume resistivity can be obtained. This is because an organic material such as a dispersant contained in the silver nanoink evaporates during firing at high temperature, and a conductive layer having a small amount of a component other than silver can be formed.

The volume resistivity of the conductive layer can be measured, for example, according to resistance measurement (JIS K7194) using a 4-point probe method.

In the present disclosure, a low resistivity meter (Loresta GX MCP-T700, commercially available from Nittoseiko Analytech co., ltd.) was used to measure volume resistivity according to JIS K7194:1994. Specifically, the volume resistivity was measured by the following method.

The surface layer and the elastic layer are peeled off from the fixing rotary member, 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 were removed with a solvent (e solution 21KZE-100, commercially available from Kaneko Chemical co., ltd.) to obtain a conductive layer. The volume resistance value is measured by bringing the measuring probe of the above device into direct contact with the obtained conductive layer. The probes 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 having an electrode diameter of 150 μm is selected. For the resistance values of the conductive layers, the resistance values of the plurality of conductive layers were measured, and the average value thereof was used as the volume resistivity of the conductive layer of the member.

As described above, in a cross-sectional view in a longitudinal direction orthogonal to the circumferential direction of the fixing rotary member, the conductive layer 20b may be constituted by a plurality of ring-shaped conductive regions 201, the plurality of ring-shaped conductive regions 201 being electrically independent from each other (see fig. 4). By adopting such a configuration, even if one of the conductive regions 201 breaks and becomes difficult to generate heat in the broken conductive region, the heat generation capability of the entire conductive layer (entire electro-conductive layer) 20b is not greatly affected.

In view of this, when the above-described configuration is adopted, the conductive layer 20b is considered to be oxidized due to the increase in the total surface area (whole surface area). However, by using silver as a material for the conductive layer, deterioration due to oxidation of the conductive layer can be effectively suppressed.

As shown in fig. 4, when the conductive layer 20b is constituted by a plurality of ring-shaped conductive regions 201, the width of the conductive regions in the cross-sectional view in the longitudinal direction of the fixing rotary member may be preferably 100 μm or more, more preferably 200 μm or more in view of excellent heat generating ability. In addition, in view of preventing uneven heat generation, the width of each conductive region 201 may be preferably 500 μm or less, more preferably 400 μm or less. The width of each conductive region may be preferably, for example, 100 to 500 μm and more preferably 200 to 400 μm. Furthermore, the width of each conductive region may preferably be substantially constant. Further, from the viewpoint of preventing short-circuiting between the conductive regions, the distance between the conductive regions constituting the conductive layer 20b is preferably 50 μm or more, more preferably 100 μm or more. Further, from the viewpoint of suppressing heat generation unevenness of the fixing rotary member, the distance between the conductive regions may be preferably 400 μm or less, more preferably 300 μm or less. The distance may be, for example, preferably 50 to 400 μm and more preferably 100 to 300 μm.

For the conductive layer 20b, it is desirable that the difference between the compressive elastic modulus in the compression direction and the compressive elastic modulus of the base member and the resin layer is small. If the difference in compressive elastic modulus between the base member or the resin layer and the conductive layer is small, when the end portion of the paper (so-called paper edge) is locally compressed and deformed, it is possible to prevent excessive stress from being applied at the interface between the conductive layer and the base member or the resin layer. As described above, the base member is preferably formed of a heat-resistant resin as a main component. Therefore, even if silver is the main component, it is desirable that the modulus of elasticity in compression of the conductive layer 20b is as low as possible.

The compressive elastic modulus of the conductive layer is 8 to 30GPa. The modulus of elasticity in compression is measured by: a Berkovich-type indenter was brought into contact with a first surface of the conductive layer opposite to a surface facing the base member, and then pressed into the conductive layer to a depth of 1 μm from the first surface of the conductive layer to measure the compressive elastic modulus at each depth position. Then, an average value of elastic modulus in a depth region of 10 to 20% with respect to a press-in depth of 1 μm from the first surface, that is, a depth region of a range of 0.1 μm to 0.2 μm from the first surface was calculated. The average value obtained was used as the compressive elastic modulus of the conductive layer.

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

When the compressive elastic modulus of the conductive layer is set within the above range, the difference in compressive elastic modulus from the resin material for the base member can be reduced. As a result, excessive stress can be prevented from being applied at the interface between the conductive layer and the base member or the resin constituting the resin layer, and durability can be improved.

The modulus of elasticity in compression of the conductive layer is preferably within 6 times the modulus of elasticity in compression of the base member. The modulus of elasticity in compression of the base member is measured in the same manner as the modulus of elasticity in compression of the elastic layer.

Specifically, a Berkovich-type indenter was pressed into a position of the base member at a depth of 1 μm from a first surface of the base member, which is opposite to a surface on which the conductive layer was formed, and a compressive elastic modulus at each depth position was measured. An average value of the compressive elastic moduli in a thickness range of 0.1 μm to 0.2 μm from the first surface of the base member is used as the compressive elastic modulus of the base member. As for the base member having a thickness of 40 μm and composed of polyimide exemplified as a preferable material, the modulus of compressive elasticity is, for example, 5GPa. Therefore, regarding the compressive elastic modulus of the conductive layer on the polyimide base member made of polyimide, it may be preferably 6 times or less, that is, 30GPa or less, of the compressive elastic modulus of the base member. Here, the compressive elastic modulus of the resin base member may preferably be 2.5 to 6.0GPa.

The compressive modulus of elasticity may be reduced by forming voids in the conductive layer while maintaining the desired conductivity of the conductive layer. When the conductive layer has pores, the conductive layer may also be deformed by conforming to deformation of the resin and the resin layer constituting the base member upon receiving local compressive stress, and may receive excessive stress. As a result, occurrence of cracks can be reduced, and durability of the conductive layer can be improved.

As the size and proportion of voids in the conductive layer increases, the compressive elastic modulus of the conductive layer may remain low. However, if the porosity of the conductive layer is too large, problems in terms of conductivity and durability may occur. Therefore, it is desirable to adjust the size and proportion of the pores so that the compressive elastic modulus of the conductive layer is not less than 8GPa.

The method of forming the aperture in the conductive layer 20b is not particularly limited, and for example, a method of forming a pattern on the conductive layer 20b according to a photolithography process and then forming the aperture by chemical etching and a method of forming the aperture using a laser or a focused ion beam may be exemplified. In the present disclosure, in particular, pore formation using silver nanoparticle materials will be described.

First, a film of a coating obtained by adding silver nanoparticles having a particle diameter of about 10 to 50nm is formed. Therefore, as shown in fig. 8A, particles are laminated. Due to the instability of the surface energy of the silver nanoparticles, the silver nanoparticles are fused together by firing at a low temperature of about 100 ℃, and as shown in fig. 8B, a coating having nano-sized pores can be obtained. The conductive layer 20b is preferably a sintered body of silver nanoparticles.

In addition, when the laminate in which the silver nanoparticle film is formed is fired (sintered) at 300 ℃ to 400 ℃, the nano-sized pores in the coating layer are combined to form large pores, and finally through-holes that are open on both the surface on the base member side and the surface opposite to the surface on the base member side are formed, as shown in fig. 8C. That is, when the conductive layer is formed using the silver nanoink, the number of pores and the size of the pores can be adjusted by increasing the firing temperature of the silver nanoink layer formed on the surface of the base member and by extending the firing time.

The size and number of pores in the conductive layer may be expressed as porosity. Here, the porosity in the conductive layer is obtained as follows.

Preparation of sample for evaluation

First, a sample for evaluation was prepared. From the fixing rotating member, one sample having a length of 5mm, a width of 5mm, and a thickness equal to the total thickness of the fixing rotating member was collected from an arbitrary position on the fixing rotating member.

For the obtained sample, a cross section of the fixing rotary member in the circumferential direction was polished using an ion beam. In this case, the processing position is adjusted so that the cross section of the conductive layer in the circumferential direction is exposed by ion beam milling. The method of polishing the cross section with the ion beam is not particularly limited, but in the present disclosure, a cross section polisher is used. According to the polishing of the cross section with the ion beam, the filler can be prevented from falling off from the sample and the abrasive can be mixed in, and the cross section with few grinding marks can be formed.

Cross-sectional view and image processing of conductive layers

The cross section of the conductive layer obtained by the above method was observed under a Scanning Electron Microscope (SEM) (product name: JSM-F100, commercially available from JEOL ltd.) and a cross-sectional image (SEM image) was obtained. The observation condition was a back-scattered electron image mode at 20,000 times magnification, and the reflected electron image acquisition condition was an acceleration voltage of 3.0kV and a working distance of 3 mm. An example of an SEM image of the fixing rotary member 100 is shown in fig. 1. In fig. 1, the fixing rotary member 100 includes a base member 101, a conductive layer 103 on the base member 101, and a resin layer 105 on the conductive layer 103. The conductive layer illustrated in fig. 1 comprises silver crystals 103-1 and at least one aperture 107 is included in the exemplary conductive layer 103.

The cut image is subjected to binarization processing so that the crystal grains are displayed in white, and the portions other than the crystal grains are displayed in black. As the binarization method, for example, otsu method disclosed in IEEE Transactions on SYSTEMS, MAN, AND CYBERNETICS, vol.SMC-9, no.1, month 1 in 1979, pages 62-66 can be used.

Specifically, first, a reflected electronic image was read using image analysis software (ImageProPlus, commercially available from MediaCybernetics), the image was cut out at an arbitrary position in a size range of 0.5 μm×0.5 μm, and the luminance distribution of the image was obtained. Next, when the luminance range of the obtained luminance distribution is set, binarization may be performed in which crystalline particles and portions other than the crystalline particles may be distinguished.

Calculation of porosity

In the binarized image obtained in this process, the metal crystal particles are represented as white areas. The porosity is calculated by calculating the area occupied by these crystalline particles in the image.

Specifically, in the binarized image, the number of pixels composed of crystal grains is calculated, and the sum of the numbers of pixels is calculated. The area occupied by the crystalline particles can be calculated by multiplying the sum of the numbers of pixels by the area of one pixel (0.15×0.15=0.0225 μm ²).

Since the porosity represents a proportion of the space in the conductive layer that is not occupied by the crystalline particles, the area occupied by the crystalline particles obtained above is used to determine as follows.

Porosity = { binarized image area (0.5x0.5 (μm ²)) -area occupied by crystalline particles (μm ²)) }/binarized image area (0.5x0.5 (μm ²)) ×100

The average porosity obtained by averaging the porosities obtained at 20 arbitrary positions in the binarized image of the conductive layer cross section is used as the porosity of the conductive layer.

The porosity of the conductive layer is preferably 15% or more, more preferably 20% or more, and still more preferably 25% or more. Within the above range, the compressive elastic modulus can be reduced while maintaining the desired conductivity of the conductive layer.

The upper limit of the porosity of the conductive layer is preferably 50% or less, more preferably 48% or less, and still more preferably 45% or less in view of conductivity and durability. Within the above range, both conductivity and durability can be achieved. For example, preferably, ranges of 15 to 50%, 20 to 48%, and 25 to 45% can be exemplified.

When the pores are formed using the silver nanoparticle material according to the above method, the porosity can be controlled according to the firing temperature at the time of forming the conductive layer. Specifically, if the firing temperature is high, the porosity is large because fusion of the silver nanoparticles is promoted.

The firing temperature of the conductive layer is preferably 100 ℃ or higher, more preferably 150 ℃ or higher. Within the above range, a sufficient amount of pores may be formed to improve durability.

The firing temperature of the conductive layer is preferably 400 ℃ or lower, more preferably 350 ℃ or lower. Within the above range, the porosity does not become too large, and the conductivity and durability of the conductive layer can be maintained. For example, preferably, a range of 100 to 400 ℃ and 150 to 350 ℃ can be exemplified.

The firing time of the conductive layer is not particularly limited, and for example, a range of 10 to 120 minutes can be exemplified.

(4) Resin layer

The fixing rotary member has a resin layer 20e on a surface of the conductive layer on the opposite side to the side facing the base member. The resin layer 20e protects the conductive layer 20b and has 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. As with the resin of the base member 20a, the resin used in the resin layer 20e is preferably a resin which has little change in physical properties when the conductive layer 20b generates heat and can maintain high strength. Therefore, the resin layer 20e preferably includes a heat-resistant resin as a main component, and is preferably formed of a heat-resistant resin. The heat-resistant resin is, for example, a resin that does not melt or decompose at a temperature lower than 200 ℃ (preferably lower than 250 ℃).

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, and more preferably includes at least one selected from the group consisting of polyimide and polyamideimide. Regarding the modification, those described in the base member 20a are similarly applied. The method of forming the base member 20a and the resin layer 20e is not particularly limited. For example, the imide material in liquid form, known as varnish, may be applied using known methods and fired to form a coating.

The material of the resin layer may be analyzed by the same method as in the analysis of the material of the base member.

The resin layer 20e may include a thermally conductive filler in view of heat transfer. When the heat transfer is improved, the heat generated in the conductive layer 20b can be efficiently transferred to the outer surface of the fixing rotary member.

The thickness of the resin layer 20e is preferably 10 to 100 μm, more preferably 20 to 60 μm. In view of the bending resistance of the conductive layer 20b, the thickness of the resin layer 20e is preferably the same as the thickness of the base member 20 a. For example, the ratio of the thickness difference between the base member and the resin layer to the thickness of the base member is preferably 20% or less, 10% or less, or 5% or less. This is because, as the thickness difference decreases, the stress applied to the conductive layer 20b is uniformly distributed when the nip portion is repeatedly bent, and the occurrence of cracks in the conductive layer 20b can be reduced.

(5) Elastic layer

The fixing rotary member may have an elastic layer on the outer surface of the resin layer 20e as needed. The elastic layer 20c is a layer for imparting flexibility to the fixing rotary member so as to fix the fixing nip in the fixing device. Here, when the fixing rotary member is used as a heating member that contacts the toner on the paper, the elastic layer 20c also functions as a layer that imparts surface softness to the heating member so that it can conform to the irregularities of the paper.

The elastic layer 20c includes, for example, a 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 formed of a cured product obtained by curing a composition containing at least a rubber raw material (base polymer, crosslinking agent, etc.) and a thermally conductive filler.

In order to exhibit the function of the elastic layer 20c described above, the elastic layer 20c is preferably formed of a cured product of silicone rubber containing thermally conductive particles, and more preferably formed of a cured product of an addition-curable silicone rubber composition.

The silicone rubber composition may include, for example, thermally conductive particles, a base polymer, a crosslinking agent, and a catalyst, and additives as necessary. Since most silicone rubber compositions are liquid, the thermally conductive filler is easily dispersed, and if the degree of crosslinking is adjusted according to the type and amount of the thermally conductive filler added, the elasticity of the elastic layer 20c to be produced is easily adjusted.

The substrate has a function of exhibiting elasticity in the elastic layer 20 c. The matrix preferably comprises silicone rubber so as to exhibit the function of the elastic layer 20c described above.

Silicone rubber is preferred because it has high heat resistance and thus maintains flexibility even in environments where the non-paper passing area reaches a high temperature of about 240 ℃. As the silicone rubber, for example, a cured product of an addition-curable liquid silicone rubber composition to be described below can be used. The elastic layer 20c may be formed by applying and heating a liquid silicone rubber composition by a known method.

The liquid silicone rubber composition generally comprises the following components (a) to (d).

Component (a): an organopolysiloxane having an unsaturated aliphatic group;

Component (b): an organopolysiloxane having active hydrogen bonded to silicon;

Component (c): a catalyst;

Component (d): thermally conductive filler

Hereinafter, the respective components will be described.

Component (a)

Examples of the organopolysiloxane having an unsaturated aliphatic group include organopolysiloxanes having an unsaturated aliphatic group such as a vinyl group. Examples thereof include those represented by the following formulas (1) and (2).

In formula (1), m ¹ represents an integer of 0 or more, and n ¹ represents an integer of 3 or more. Each R ¹ independently represents a monovalent unsubstituted or substituted hydrocarbon group free of unsaturated aliphatic groups, and at least one R ¹ represents a methyl group. R ² each independently represents an unsaturated aliphatic group.

In formula (2), n ² represents a positive integer. Each R ³ independently represents a monovalent unsubstituted or substituted hydrocarbon group free of unsaturated aliphatic groups, and at least one R ³ represents a methyl group. R ⁴ each independently represents an unsaturated aliphatic group.

Examples of the monovalent unsubstituted or substituted hydrocarbon group having no unsaturated aliphatic group which may be represented by R ¹ and R ³ in the formula (1) and the formula (2) include the following groups.

Unsubstituted hydrocarbylalkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl). Aryl (e.g., phenyl).

Substituted hydrocarbyl-substituted alkyl (e.g., chloromethyl, 3-chloropropyl, 3-trifluoropropyl, 3-cyanopropyl, 3-methoxypropyl).

The organopolysiloxane represented by formula (1) and formula (2) has at least one methyl group directly bonded to a silicon atom forming a chain structure. However, from the viewpoint of ease of synthesis and handling, more than 50% of each of R ¹ and R ³ is preferably methyl, and all R ¹ and R ³ are more preferably methyl.

In addition, examples of the unsaturated aliphatic groups which may be represented by R ² and R ⁴ in the formula (1) and the formula (2) include vinyl, allyl, 3-butenyl, 4-pentenyl and 5-hexenyl. Of these groups, both of R ² and R ⁴ are preferably vinyl groups because they are easy to synthesize and handle, inexpensive, and easy to undergo a crosslinking reaction.

In view of formability, the viscosity of the component (a) is preferably 1,000 to 50,000mm ²/s. If the viscosity (dynamic viscosity) is less than 1,000mm ²/s, it becomes difficult to adjust the hardness to that required for the elastic layer 20c, and if the viscosity is more than 50,000mm ²/s, the viscosity of the composition becomes excessively high, and coating becomes difficult. The viscosity (dynamic viscosity) can be measured using a capillary viscometer, a rotational viscometer, or the like based on JIS Z8803:2011.

Based on the addition amount of the component (a) of the liquid silicone rubber composition for forming the elastic layer 20c, it is preferably 55% by volume or more in view of durability, and it is preferably 65% by volume or less in view of heat transfer.

Component (b)

The organopolysiloxane having active hydrogen bonded to silicon acts as a cross-linking agent and reacts with the unsaturated aliphatic group of component (a) under the action of a catalyst to form a cured silicone rubber.

As component (b), any organopolysiloxane having Si-H bonds can be used. In particular, those having an average of 3 or more hydrogen atoms bonded to a silicon atom in one molecule are preferably used in view of reactivity with the unsaturated aliphatic group of the component (a).

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

In formula (3), m ² represents an integer of 0 or more, and n ³ represents an integer of 3 or more. R ⁵ each independently represents a monovalent unsubstituted or substituted hydrocarbon group free of unsaturated aliphatic groups.

In formula (4), m ³ represents an integer of 0 or more, and n ⁴ represents an integer of 3 or more. R ⁶ each independently represents a monovalent unsubstituted or substituted hydrocarbon group free of unsaturated aliphatic groups.

Examples of the monovalent unsubstituted or substituted hydrocarbon group not containing an unsaturated aliphatic group which can be represented by R ⁵ and R ⁶ in the formula (3) and the formula (4) include the same groups as R ¹ in the above formula (1). Among them, 50% or more of each of R ⁵ and R ⁶ is preferably methyl, and all of R ⁵ and R ⁶ are more preferably methyl, because they are easy to synthesize and handle and excellent heat resistance is easy to obtain.

Component (c)

Examples of catalysts for forming silicone rubber include hydrosilylation catalysts for promoting the curing reaction. As the hydrosilylation catalyst, for example, known substances such as platinum compounds and rhodium compounds can be used. The addition amount of the catalyst 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 (Si ₃N₄), boron Nitride (BN), aluminum nitride (AlN), aluminum oxide (Al ₂O₃), zinc oxide (ZnO), magnesium oxide (MgO), silicon dioxide (SiO ₂), copper (Cu), aluminum (Al), silver (Ag), iron (Fe), nickel (Ni), vapor grown carbon fibers, PAN (polyacrylonitrile) based carbon fibers, pitch based carbon fibers.

These fillers may be used alone or two or more thereof may be used in combination.

The average particle diameter of the filler is preferably 1 to 50 μm in view of handling and dispersibility. In addition, as the shape of the filler, spherical, powdery, needle-like, plate-like, and whisker-like shapes are used.

In particular, the filler is preferably in the shape of a sphere in view of dispersibility. In addition, at least one of a reinforcing filler, a heat-resistant filler, and a coloring filler may be added.

(6) Adhesive layer

The fixing rotary member may have an adhesive layer 20f for adhering a surface layer 20d described below to the outer surface of the elastic layer 20 c.

The adhesive layer 20f is a layer for adhering the elastic layer 20c and the surface layer 20 d. The adhesive used in the adhesive layer 20f is not particularly limited, and any adhesive appropriately selected from known adhesives is used. However, in view of ease of handling, addition-curable silicone rubber to which a self-adhesive component is added is preferably used.

The adhesive for the adhesive layer 20f may include, for example, a self-adhesive component, an organopolysiloxane having a plurality of unsaturated aliphatic groups represented by vinyl groups in a molecular chain, a hydrogen organopolysiloxane, and a platinum compound as a crosslinking catalyst. When the adhesive applied to the surface of the elastic layer 20c is cured according to the addition reaction, an adhesive layer 20f may be formed such that the surface layer 20d adheres to the elastic layer 20 c.

Examples of the self-adhesive component include the following.

Silane having at least one, preferably 2 or more functional groups selected from the group consisting of alkenyl groups such as vinyl groups, (meth) acryloxy groups, hydrosilyl groups (SiH groups), epoxy groups, alkoxysilyl groups, carbonyl groups, and phenyl groups.

Organosilicon compounds, for example cyclic or linear siloxanes having from 2 to 30 silicon atoms, preferably from 4 to 20 silicon atoms.

Non-silicon organic compounds that may contain oxygen atoms in the molecule (i.e., no silicon atoms in the molecule). However, the compound contains 1 to 4, preferably 1 to 2 aromatic rings, for example, a phenylene structure having a valence of 1 to 4, preferably 2 to 4 in one molecule. Furthermore, the compound contains at least one, preferably 2 to 4, functional groups (e.g., alkenyl, (meth) acryloyloxy) in one molecule that can contribute to the hydrosilylation addition reaction.

The self-adhesive components may be used alone or two or more thereof may be used in combination. In addition, in order to adjust viscosity and ensure heat resistance, a filler component may be added to the adhesive within the scope of the gist of the present disclosure. Examples of filler components include the following.

Silica, alumina, iron oxide, cerium hydroxide, carbon black, and the like.

The addition amount of each component contained in the adhesive is not particularly limited, and may be appropriately set. Such addition-curable silicone rubber adhesives are commercially available and readily available. The thickness of the adhesive layer is preferably 20 μm or less. If the thickness of the adhesive layer is set to 20 μm or less, when the fixing belt according to the present aspect is used as a heating belt in a thermal fixing device, the thermal resistance can be easily set small, and heat from the inner surface can be easily and effectively transferred to the recording medium.

(7) Surface layer

The fixing rotary member may have a surface layer 20d as necessary.

The surface layer preferably includes a fluororesin so as to exhibit a function as a release layer that prevents toner from adhering to the outer surface of the fixing rotary member. The surface layer may be formed using, for example, a resin shaped into a tube as exemplified below, or may be formed by coating a resin dispersion.

Tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and the like.

Among the above exemplified resin materials, PFA is particularly preferably used in view of moldability and toner releasability.

The thickness of the surface layer 20d is preferably 10 to 50 μm. When the thickness of the surface layer 20d is set within the above range, it is easy to maintain an appropriate surface hardness of the fixing rotary member.

According to one aspect of the present disclosure, there is provided a fixing device in which a rotary member for fixing is provided. Accordingly, it is possible to provide a fixing device in which a rotary member for fixing having high conductivity and excellent durability is provided. Further, an image forming apparatus using the fixing device may be provided.

(8) Method for manufacturing rotary member for fixing

For example, a non-limiting manufacturing method of a rotary member (pressing belt or pressing roller) for fixing according to one aspect of the present disclosure includes a base member, a conductive layer on the base member, and a resin layer on a surface of the conductive layer opposite to a side facing the base member, wherein the conductive layer includes silver. Examples of the manufacturing method using the silver nanoparticle material include methods including the following steps (i) to (iii).

(I) A step of obtaining a base member;

(ii) A step of obtaining a conductive layer by applying silver nanoparticle ink to the outer peripheral surface of the base member obtained in step (i) and firing; and

(Iii) A step of obtaining a resin layer by applying a resin material to the conductive layer obtained in step (ii) and firing.

Examples

The present disclosure will be described in more detail below with reference to examples and comparative examples, but the present disclosure is not limited thereto.

Example 1

A cylindrical stainless steel mold having an outer diameter of 30mm and a length of 460mm in a longitudinal direction orthogonal to the circumferential direction of the mold was provided. And (3) demolding the outer peripheral surface of the mold. The mold was then fully immersed in a commercially available polyimide precursor solution (U varish S, commercially available from Ube Industries, ltd.) to form a coating film of the solution. Next, the coating film was heated at 140 ℃ for 30 minutes to evaporate the solvent in the coating film. Then it was heated at 200℃for 30 minutes and then at 400℃for 30 minutes to form a polyimide film having a thickness of 40. Mu.m. Then, the polyimide film was demolded to obtain a polyimide tube. Next, both ends of the obtained polyimide tube in the longitudinal direction perpendicular to the circumferential direction were cut off to form a polyimide tube having a length of 300 mm.

Next, a cylindrical core having an outer diameter of 30mm and a length of 300mm in the longitudinal direction was provided, and the outer peripheral surface was covered with the obtained polyimide tube. Next, in a central region on the outer peripheral surface of the polyimide tube, an ink (product name: DNS163; manufactured by Daicel Corporation) compounded with silver nanoparticles was applied in the circumferential direction of the polyimide tube by an inkjet method to form conductive regions in a ring shape, each of which extends toward the circumferential direction of the polyimide tube, from a region having a width of 110mm toward both ends of the center in the longitudinal direction of the polyimide tube, that is, a total width of 220mm of the central region. Then, firing was performed at 300 ℃ for 30 minutes and a conductive layer composed of a plurality of conductive regions was formed. The width of each conductive region in the length direction of the polyimide tube was 300 μm, the pitch was 200 μm and the maximum thickness was 2 μm.

Next, a commercially available polyimide precursor solution (Uvarnish S, commercially available from Ube Industries, ltd.) was applied to the entire surface on the conductive layer 20b by ring coating, followed by firing at 200 ℃ for 30 minutes, and further firing at 400 ℃ for 30 minutes for imidization, and a resin layer 20e having a film thickness of 40 μm was formed. The resin layer covers the exposed face of the polyimide tube (i.e., the outer surface of the polyimide tube not covered with the conductive region) and the surface of the conductive region.

Next, a primer (product name: DY39-051A/B, commercially available from Dow Toray co., ltd.) was substantially uniformly applied to the outer peripheral surface of the resin layer 20e so that the dry weight was 20mg, the solvent was dried, and then baking treatment was performed in an electric furnace set at 160 ℃ for 30 minutes.

A silicone rubber composition layer having a thickness of 250 μm was formed on the primer by a ring coating method, and was subjected to primary crosslinking at 160 ℃ for 1 minute, and then to secondary crosslinking at 200 ℃ for 30 minutes, to form an elastic layer 20c.

Here, the following silicone rubber composition was used.

As the organopolysiloxane having alkenyl groups as the component (a), a vinylized polydimethylsiloxane having at least two or more vinyl groups in one molecule (product name: DMS-V41, commercially available from Gelest) was prepared, and the number average molecular weight was 68,000 (based on polystyrene) and the vinyl molar equivalent was 0.04 mmol/g.

In addition, as the organopolysiloxane having Si-H groups as the component (b), methyl hydrogen polysiloxane having at least two or more Si-H groups in one molecule (product name: HMS-301, commercially available from Gelest) was prepared, and the number average molecular weight was 1,300 (based on polystyrene), and the molar equivalent of Si-H groups was 3.60 mmol/g. 0.5 parts by mass of the component (b) was added to 100 parts by mass of the component (a), and thoroughly mixed to obtain an addition-curable silicone rubber solution.

In addition, as for the amount of the catalyst (component (c)), a very small amount of an addition curing reaction catalyst (platinum catalyst: carbonyl cyclovinylmethylsiloxane platinum complex) and an inhibitor were added and mixed well.

High-purity true spherical alumina (product name: alumina beads CB-a10S; commercially available from Showa Titanium co., ltd.) is added as a thermally conductive filler (component (d)) to and kneaded with the additively curable silicone rubber cement at a volume ratio of 45% based on the elastic layer. Then, an addition-curable silicone rubber composition having a durometer hardness of 10℃according to Japanese Industrial Standard (JIS) K6253-3:2023 (type A durometer hardness) after curing was obtained.

Next, an addition-curable silicone rubber adhesive (product name: SE1819CV a/B, commercially available from Dow Toray co., ltd.) for forming the adhesive layer 20f was substantially uniformly applied to the obtained elastic layer 20c so that the thickness was about 20 μm. A fluororesin tube (product name: NSE, commercially available from Gunze ltd.) having an inner diameter of 29mm and a thickness of 50 μm for forming the skin layer 20d was laminated thereon while enlarging the diameter thereof.

Then, by uniformly rubbing the surface of the belt from above the fluororesin tube, the excessive adhesive is removed from between the elastic layer 20c and the fluororesin tube so that the thickness is made as thin as about 5 μm. Next, the adhesive was cured by heating at 200 ℃ for 30 minutes, the fluororesin tube was fixed on the elastic layer 20c, and finally both ends were cut out to have a length of 240mm, 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 changed to 3 μm.

Examples 3 to 4

A fixing belt was produced in the same manner as in example 1, except that the firing temperatures of the conductive layers were set as shown in table 1, respectively.

Example 5

A rotary member for fixing was produced in the same manner as in example 1, except that a polyamideimide solution (Vylomax HR-16NN, commercially available from Toyobo co., ltd.) was used as a material of the resin layer 20e and applied to the entire surface by ring coating, and then firing was performed at 200 ℃ for 30 minutes to form the resin layer 20e having a film thickness of 40 μm.

Examples 6 to 7

A fixing belt was produced in the same manner as in example 5 except that the firing temperature of the conductive layer was set as shown in table 1.

Comparative example 1

A rotary member for fixing was produced in the same manner as in example 1, except that the conductive layer 20b was formed by a silver plating method.

The formation of the conductive layer 20b by the silver plating method is performed by the following method.

A cylindrical polyimide film was prepared and an annular masking material (ring-SHAPED MASKING MATERIAL) was disposed on the surface thereof. Subsequently, a plating treatment was performed using a silver potassium cyanide bath as a silver plating bath. The pH of the plating bath is maintained at 8 to 9, and the temperature of the plating bath is maintained at 50 to 70 ℃. After being taken out from the plating bath, the masking material was removed by a washing step to obtain a base layer on which a conductive layer having a thickness of 2.0 μm was formed.

Comparative example 2

A rotary member for fixing was produced in the same manner as in example 4, except that the firing temperature of the conductive layer 20b was set to 120 ℃.

Comparative example 3

A rotary member for fixing was produced in the same manner as in example 1, except that copper was used as a material of the conductive layer 20b 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, heat generation was insufficient when image evaluation was performed using a real machine, and image defects occurred.

This is thought to be due to the fact that oxidation of copper progresses when the resin layer is formed and the volume resistivity of the conductive layer increases.

Cross-sectional view and image processing of conductive layers

From the fixing belt, 20 samples each having a length of 5mm, a width of 5mm and a thickness equal to the total thickness of the fixing belt were collected from an arbitrary position on the fixing belt. Each of the obtained samples was polished using an ion mill (product name: IM4000, manufactured by HITACHI HIGH-Technologies Corporation) so that a cross section along the circumferential direction of the fixing belt in the total thickness direction of the fixing belt was exposed. Here, polishing of the cross section by ion milling here makes it possible to prevent particles from falling off the sample and prevent contamination of the abrasive, while enabling formation of a cross section exhibiting few polishing marks.

Next, the cross section of the conductive layer exposed in the polished cross section of each sample in the thickness direction was then observed with a schottky field emission Scanning Electron Microscope (SEM) (product name: FE-SEM JSM-F100, manufactured by JEOL ltd.) equipped with an energy dispersive X-ray spectrometer (EDS) to obtain a cross-sectional image. As observation conditions, a back-scattered electron imaging mode at 20000 magnification was employed, and as conditions for back-scattered electron image acquisition, an acceleration voltage was set to 3.0kV and a working distance was set to 3mm.

Next, the obtained sectional image is subjected to binarization processing so that the crystal grains are displayed white and the portions other than the crystal grains are displayed black. As the binarization method, the Otsu method disclosed in IEEE Transactions on SYSTEMS, MAN, AND CYBERNETICS, vol.SMC-9, no.1,1979, month 1, pages 62-66 was used. Specifically, first, a sectional image was read using image analysis software (product name: imageProPlus, commercially available from MediaCybernetics), and an image having a size range of 0.5 μm×0.5 μm was cut out at an arbitrary position, and a luminance distribution of the image was obtained. Next, from the luminance distribution, a binarized image in which the region corresponding to the silver crystal and the other regions are distinguished is obtained according to the Otsu method.

Calculation of porosity

In the binarized image obtained in the process, the metal crystal particles are represented as white areas. The porosity is calculated by calculating the area occupied by these crystal particles in the image. Specifically, in the binarized image, the number of pixels corresponding to the crystal of silver was counted, however, the area occupied by the crystal was calculated by multiplying the number of pixels by the area of one pixel (0.15×0.15=0.0225 μm ²). Since the porosity represents the proportion of the space in the conductive layer not occupied by the crystal particles, the area occupied by the crystal particles obtained above was determined as follows:

porosity = { area of binarized image (0.5x0.5 (μm ²)) -area occupied by crystal particles (μm ²)) }/area of binarized image (0.5x0.5 (μm ²)) ×100

The arithmetic average of the porosities calculated by the above procedure of the 20 samples was taken as the porosity of the conductive layer.

Purity of silver in conductive layer

Elemental analysis was performed on a cross section of the conductive layer exposed on the polished surface of the sample. Elemental analysis was performed with EDS mounted on JSM-F100 at an acceleration voltage of 5-15 kV and a magnification of 4000 times. In addition, elemental analysis was performed on any three (3) positions in the cross section of the conductive layer. Thus, elemental analysis was performed at 60 positions in total, i.e., 3 positions×20 samples.

The arithmetic average of the purities of the silver obtained at 60 positions was then used as the purities of the silver in the conductive layer of the observed fixing belt.

Evaluation: modulus of elasticity under compression

< Conductive layer >

The compressive elastic modulus of the conductive layer was measured by the following method.

First, the surface layer and the elastic layer are peeled off from the fixing rotary member, and the laminate of the base layer, the conductive layer, and the resin layer is taken out. Next, a polyimide film remover (e solve KZE-100, commercially available from Kaneko Chemical co., ltd.) was applied to the surface of the resin layer and heated at 40 ℃ for 10 minutes.

Then, cooling to room temperature, namely 25 ℃, followed by washing with pure water, drying to remove the resin layer, and exposing the conductive layer on the opposite side to the surface facing the base member. The compressive elastic modulus of the exposed conductive layer surface was measured using a Berkovich-type indenter using a micro-indentation hardness tester (product name: nano INDENTER G, commercially available from Agilent Technologies, inc.).

Here, the measurement region was pressed with a pressing head to a depth of 1 μm in the thickness direction from the first surface of the conductive layer opposite to the surface facing the base layer, and an average value of compression modulus at a depth position measured in a region of 10 to 20% with respect to the pressed depth, i.e., a depth region of 0.1 μm to 0.2 μm from the first surface was calculated. The average value of the elastic modulus is taken as the compression elastic modulus of the conductive layer. The measurement of the modulus of elasticity under compression was carried out at a temperature of 25℃and a relative humidity of 50%. The results are shown in tables 1-2.

< Base Member >

The modulus of elasticity in compression of the base member is measured in the same manner as the modulus of elasticity in compression of the conductive layer. In measurement, a Berkovich-type indenter is contacted with a first surface of the base member opposite the surface facing the conductive layer and pressed into the base member.

Evaluation: durability test of real machine

The fixing belts of examples 1 to 7 and comparative examples 1 to 3 were subjected to a paper passing durability test under the following conditions.

Each of the fixing belts of examples 1 to 7 and comparative examples 1 to 3 was introduced into a fixing device, which was mounted in a laser printer (product name: satera LBP961Ci, manufactured by Canon inc.) and was subjected to a paper passing durability test by passing 200 ten thousand sheets of A4-sized paper (product name: color laser NPI high quality thick port (high-quality thick mouth), A4 size, tidal volume 128g/m ², thickness 148 μm, canon Marketing Japan manufactured) without printing any image in an environment where the atmospheric temperature was 15 ℃ and the humidity was 10%, and for every 10,000 sheets, it was checked whether there was any deformation at a position of the base member corresponding to a position contacting an edge of the paper. Here, the laser printer is modified so that the pressing roller and the fixing rotary member can rotate at a higher speed (linear speed of 400 mm/s) than usual.

Further, after passing through 200 ten thousand sheets, a cyan solid image was formed on one sheet with a laser printer. The solid image obtained was checked with naked eyes for the presence of image defects, and evaluated according to the following criteria.

Class a: even after 200 ten thousand sheets were passed, no deformation was observed in the base member, and no image defect was observed in the solid image.

Class B: after 200 ten thousand sheets were passed, deformation was observed at a position of the base member corresponding to a position contacting the edge of the sheet. On the other hand, in the solid image, any image defect due to deformation is not observed.

Grade C: before the number of sheets reaches 200 ten thousand sheets, deformation is observed at a position of the base member corresponding to a position contacting the edge of the sheet. Further, in the solid image, image defects due to deformation are observed. The evaluation results are shown in tables 1 to 2. In addition, in remarks of tables 1 to 2, regarding comparative examples 1 to 3, the number of sheets in which deformation of the base member was observed for the first time was described.

[ Table 1-1]

[ Tables 1-2]

In Table 1-1, PI represents polyimide, and PAI represents polyamideimide.

Based on the results in tables 1-1 and 1-2, it is understood that when the compressive elastic modulus of the conductive layer is kept low, buckling deformation is not generated even when used as a rotary member for fixation for a long time, and durability is high. Further, it can be understood that in embodiments 1 to 7, the volume resistivity of the conductive layer is low to such an extent that conductivity can be maintained, and occurrence of image defects can be reduced.

As the porosity increases, the compressive elastic modulus of the conductive layer remains low. Further, it is understood that when silver nanoink is used as the metal type, the porosity may be adjusted according to the firing temperature of the conductive layer. The higher the firing temperature is, the higher the porosity is, and the compression elastic modulus is lowered.

According to one aspect of the present disclosure, there is provided a rotary member for fixing having high conductivity and excellent durability. Further, according to another aspect of the present disclosure, there is provided a fixing device using the rotary member for fixing. Further, according to still another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus using the fixing device.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A rotary member for fixing is characterized in that,

The fixing rotary member includes:

a cylindrical base member containing at least a resin;

a conductive layer on the base member; and

A resin layer on a surface of the conductive layer, the surface being opposite to a surface facing the base member,

The conductive layer extends in a circumferential direction of an outer peripheral surface of the base member,

The conductive layer comprises silver and the conductive layer comprises silver,

The volume resistivity of the conductive layer is 1.0X10 ^-8 to 8.0X10 ^-8 Ω & m, and

The compressive elastic modulus of the conductive layer is 8 to 30GPa, the compressive elastic modulus is measured by bringing a indenter into contact with a first surface of the conductive layer opposite to a surface facing the base member, and the compressive elastic modulus is an average of compressive elastic moduli of a thickness region of 0.1 to 0.2 μm from the first surface of the conductive layer.

2. The rotary member for fixing according to claim 1, wherein the resin is at least one selected from the group consisting of polyimide and polyamideimide.

3. The rotary member for fixing according to claim 1, wherein the conductive layer has a maximum thickness of 4 μm or less.

4. The rotary member for fixation according to claim 1, wherein the conductive layer has pores in a sectional view in a circumferential direction of the conductive layer.

5. The rotary member for fixation according to claim 4, wherein the conductive layer has a porosity of 15 to 50% in a cross-sectional view of the conductive layer.

6. The rotary member for fixing according to claim 1, wherein the conductive layer consists essentially of silver.

7. The rotary member for fixation according to claim 1, wherein the conductive layer is a sintered body of silver nanoparticles.

8. The rotary member for fixing according to claim 1, wherein the conductive layer includes a plurality of conductive regions electrically independent from each other in a sectional view in a direction perpendicular to a circumferential direction of the rotary member for fixing.

9. The rotary member for fixing according to claim 1, wherein the compressive elastic modulus of the conductive layer is 6 times or less of the compressive elastic modulus of the base member, the compressive elastic modulus of the base member being an average value of compressive elastic moduli in a thickness region of 0.1 to 0.2 μm from the first surface of the base member.

10. The rotary member for fixing according to claim 1, wherein the base member has a compression elastic modulus of 2.5 to 6.0GPa.

11. The rotary member for fixing according to claim 1, wherein the resin contained in the resin layer includes at least one selected from the group consisting of polyimide and polyamideimide.

12. The rotary member for fixing according to claim 1, wherein the resin contained in the base member comprises polyimide, and the resin contained in the resin layer comprises polyamideimide.

13. A fixing device, characterized by comprising:

The rotary member for fixing according to any one of claims 1 to 12; and

An induction heating device for heating the fixing rotary member by induction heating.

14. A fixing device according to claim 13,

Wherein the induction heating device comprises:

An exciting coil which is provided inside the fixing rotary member, has a spiral shape portion whose spiral axis is substantially parallel to a direction along the rotation axis of the fixing rotary member, and generates an alternating magnetic field that causes electromagnetic induction heating of the conductive layer; and

A magnetic core provided in the spiral-shaped portion, extending in the rotation axis direction, and forming no ring outside the fixing rotation member, and for inducing magnetic lines of force of the alternating magnetic field, wherein,

The material of the magnetic core is a ferromagnetic body, and

The conductive layer of the fixing rotating member is heated by an induction current induced by magnetic force lines, which are emitted from one longitudinal end of the magnetic core, pass through the outside of the conductive layer, and return to the other longitudinal end of the magnetic core.

15. An electrophotographic image forming apparatus, comprising:

An image bearing member that bears a toner image;

a transfer device that transfers the toner image to a recording material; and

The fixing device is a fixing device according to claim 13.

16. A method of manufacturing the rotary member for fixing according to any one of claims 1 to 12, comprising:

(i) A step of obtaining a base member;