JP2002055548A - Fixing roller member and fixing device for electromagnetic induction fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing roller member having an innovative structure, which shortens time required to elevate the temperature of a heat generation layer of a surface layer and ensures the lateral uniform temperature, and a fixing device having an innovative structure for quick start fixing, which shortens the time required to elevate the temperature of the fixing roller member and ensures the lateral uniform temperature of the fixing roller member in a nip area when paper is passed therethrough. SOLUTION: The fixing roller member for electromagnetic induction fixing has an electromagnetic induction heating body, a cylindrical elastic body, and a magnetic elastic heating layer disposed on the outside of the cylindrical elastic body. The fixing device uses the fixing roller member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., and more particularly to an electromagnetic induction fixing roller member for quick start fixing and an electromagnetic induction which can be heated instantaneously. The present invention relates to a fixing device using a fixing roller member for fixing.

[0002]

2. Description of the Related Art Conventionally, as a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., a soft heat roller fixing method having a rubber layer on a metal core as a stable one having high technical perfection. However, it is widely used in full-color machines from low-speed machines to high-speed machines.

However, in a conventional soft heat roller fixing type fixing device, when a transfer material or toner is heated,
It is necessary to heat a fixing roller having a low thermal conductivity and a large heat capacity, so that the energy effect is poor and energy saving is disadvantageous. In addition, it takes time to warm up the fixing device during printing, and printing time (warming up time) There is a problem that becomes longer.

In order to solve this problem, as a method of heating from the surface of the roller, a light-transmitting rubber layer (light-transmitting elastic layer) and a light absorbing layer (heat ray absorbing layer) are provided on the outer peripheral surface of the light-transmitting substrate. The fixing roller member was provided, and light from a hot-wire filament (heat-ray emission source) of a halogen lamp (heat-ray irradiating means) provided inside the cylindrical light-transmitting base was provided on the outer peripheral surface of the light-transmitting base. Japanese Patent Application No. 10-128917 proposes a fixing method in which a toner image is fixed by absorbing light with a light absorbing layer and heat of the light absorbing layer.

Further, the present inventors have attempted to reduce the thickness and diameter of the fixing roller member by using a cylindrical elastic body having a heat ray irradiating means (halogen lamp) therein. Is examining a fixing device for shortening the warm-up time.
No. 99 proposes.

[0006]

However, according to the proposal of Japanese Patent Application No. 10-128917, a light transmitting elastic layer and a light absorbing layer (heat ray absorbing layer) are provided on the outer peripheral surface of the light transmitting substrate. A fixing roller member is formed, and a light ray from a heat ray filament (heat ray emission source) of a halogen lamp (heat ray irradiating means) is irradiated to the light absorption layer through a light transmitting substrate or a light transmitting elastic layer, and the heat of the light absorption layer is changed. In the method of fixing the toner by the method described above, although energy saving is achieved, since the light-transmitting elastic layer made of the light-transmitting rubber layer is provided, the time required for temperature rise (warming-up time) cannot be sufficiently reduced. .

Further, in a fixing device using a cylindrical elastic body having a heat ray irradiating means (halogen lamp) inside proposed in Japanese Patent Application No. 11-230499, although energy saving is achieved, a surface heat generating layer is not provided. There is a problem that the time required for raising the temperature (warming-up time) cannot be sufficiently reduced. Further, the temperature in the lateral direction (the direction orthogonal to the transfer material feeding direction) at the nip portion during paper passing becomes non-uniform, which causes a problem that the fixing property is poor (fixing unevenness occurs).

The present invention solves the above-mentioned problems, shortens the time for raising the temperature of the surface heat-generating layer, and achieves a fixing roller member having a novel structure in which the temperature in the lateral direction is made uniform. To provide a fixing device with a novel configuration for quick start fixing that enables instantaneous heating, with the aim of shortening the heating time and making the temperature in the lateral direction of the fixing roller member uniform at the nip during paper passing. The purpose is to do.

[0009]

An object of the present invention is to provide a fixing roller member for electromagnetic induction fixing comprising an electromagnetic induction heating element, a thin cylindrical elastic element, and a magnetic elastic heating layer outside the cylindrical elastic element. (1st invention).

The object of the present invention is to provide a fixing device for fixing a toner image on a transfer material to the transfer material by heating and pressurizing, wherein an electromagnetic induction heating body, a cylindrical elastic body, and a cylindrical elastic body are provided. A magnetic elastic heat generating layer is provided on the outside to form a roll-shaped fixing roller member for electromagnetic induction fixing, and a roller having elasticity opposed to the fixing roller member for electromagnetic induction fixing and the fixing roller member for electromagnetic induction fixing. Provide a pressure roller member, deform the cylindrical elastic body, between the electromagnetic induction fixing fixing roller member and the pressure roller member,
This is achieved by a fixing device (second invention), which forms a nip portion for fixing a toner image on the transfer material.

[0011]

Embodiments of the present invention will be described below. Note that the description in this column does not limit the technical scope of the claims and the meaning of terms. Further, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning or technical scope of the terms of the present invention.

An image forming process and each mechanism of an embodiment of an image forming apparatus using a fixing device according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional configuration view of a color image forming apparatus showing an embodiment of an image forming apparatus using a fixing device according to the present invention, and FIG. 2 is a side cross-sectional view of the image forming body of FIG. 3 is a schematic cross-sectional view of a fixing device using a fixing roller member for electromagnetic induction fixing, FIG. 4 is a schematic side view showing a pressing structure of the fixing device, and FIG. FIG. 6 is a diagram illustrating a layer configuration and a function, FIG. 6 is a diagram illustrating another example of an electromagnetic induction heating body that heats a fixing roller member for electromagnetic induction fixing, and FIG. 7 is a diagram illustrating a fixing roller member for electromagnetic induction fixing. FIG. 6 is a diagram showing another example of the layer configuration of FIG.

According to FIG. 1 or FIG. 2, a photosensitive drum 10, which is an image forming body, is provided on the outer periphery of a cylindrical base formed of a light-transmitting member such as glass or light-transmitting acrylic resin. It is formed by forming a photoconductive layer and a photoconductor layer of an organic photosensitive layer (OPC).

The photoreceptor drum 10 is rotated clockwise as indicated by an arrow in FIG. 1 in a state where the light-transmitting conductive layer is grounded by power from a driving source (not shown).

In the present invention, the exposure beam for image exposure is:
The photoconductor layer of the photoconductor drum 10, which is the image forming point, only needs to have an exposure light amount of a wavelength that can provide an appropriate contrast with respect to the light attenuation characteristic (photocarrier generation) of the photoconductor layer. . Therefore, the light transmittance of the light-transmitting substrate of the photosensitive drum in the present embodiment does not need to be 100%, and may have a characteristic of absorbing a certain amount of light when transmitting the exposure beam. . The point is that any suitable contrast can be provided. As a material of the light-transmitting substrate, an acrylic resin, particularly one obtained by polymerizing a methyl methacrylate monomer, is preferably used because of its excellent light-transmitting properties, strength, accuracy, surface properties, etc. Various translucent resins such as acryl, fluorine, polyester, polycarbonate, polyethylene terephthalate and the like used for the above can be used. Further, as long as it has a light-transmitting property with respect to the exposure light, it may be colored. As the light-transmitting conductive layer, indium tin oxide (I
TO), tin oxide, lead oxide, indium oxide, copper iodide, or a metal thin film of Au, Ag, Ni, Al, or the like that maintains light transmissivity. Reactive deposition method, various sputtering methods, various CV
D method, dip coating method, spray coating method and the like can be used.
Various organic photosensitive layers (OPC) can be used as the photoconductor layer.

The organic photosensitive layer serving as the photosensitive layer of the photoconductor layer includes a charge generation layer (CGL) mainly composed of a charge generation substance (CGM) and a charge transport layer (CTM) mainly composed of a charge transport substance (CTM). And CTL). An organic photosensitive layer having a two-layer structure has high durability as an organic photosensitive layer due to its thick CTL and is suitable for the present invention.
The organic photosensitive layer may have a single layer structure containing a charge generation material (CGM) and a charge transport material (CTM) in one layer. ,
Usually, a binder resin is contained.

A scorotron charger 11 as a charging unit described below, and an exposure optical system 1 as an image writing unit will be described.
2. The developing device 13 as a developing unit is prepared for an image forming process for each color of yellow (Y), magenta (M), cyan (C) and black (K), respectively. Are arranged in the order of Y, M, C, and K with respect to the rotation direction of the photosensitive drum 10 indicated by the arrow in FIG.

Scorotron charger 11 as charging means
Is mounted so as to face and be close to the photosensitive drum 10 in a direction perpendicular to the moving direction of the photosensitive drum 10 as an image forming body (the direction perpendicular to the plane of FIG. 1). A control grid (no symbol) maintained at a predetermined potential with respect to the body layer;
As a, for example, a sawtooth electrode is used, and a charging action (in this embodiment, negative charging) is performed by corona discharge having the same polarity as that of the toner, thereby giving a uniform potential to the photosensitive drum 10. As the corona discharge electrode 11a, a wire electrode or a needle electrode may be used.

The exposure optical system 12 for each color is a linear exposure element (LED) in which a plurality of LEDs (light emitting diodes) as light emitting elements of image exposure light are arranged in an array parallel to the axis of the photosensitive drum 10. (Not shown) and a selfoc lens (not shown) as an equal-magnification imaging element are configured as an exposure unit attached to a holder. An exposure optical system 1 for each color is placed on a cylindrical holder 20 as an exposure optical system holding member.
2 is mounted and housed inside the substrate of the photosensitive drum 10. Other exposure elements include FL (phosphor emission),
A linear element in which a plurality of light emitting elements such as EL (electroluminescence) and PL (plasma discharge) are arranged in an array is used.

An exposure optical system 12 as an image writing means for each color sets an exposure position on a photosensitive drum 10 between a scorotron charger 11 and a developing device 13 and a photosensitive member with respect to the developing device 13. It is arranged inside the photoconductor drum 10 in a state provided on the upstream side in the rotation direction of the drum 10.

The exposure optical system 12 performs image processing based on image data of each color sent from a separate computer (not shown) and stored in a memory, and then forms an image on the uniformly charged photosensitive drum 10. Exposure is performed to form a latent image on the photosensitive drum 10. The emission wavelength of the light-emitting element used in this embodiment is usually 6 for the toners of Y, M, and C, which have high translucency.
The wavelength in the range of 80 to 900 nm is good, but the wavelength may be shorter than this, since the color toner does not have sufficient translucency since image exposure is performed from the back surface.

The developing device 13 as a developing means for each color includes
Inside yellow (Y), magenta (M), cyan (C)
Alternatively, it contains a black (K) two-component (or one-component) developer and is formed of, for example, a cylindrical non-magnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm, respectively. And a developing sleeve 13a as a developer carrier.

In the developing area, the developing sleeve 13a is kept out of contact with the photosensitive drum 10 with a predetermined gap, for example, 100 to 1000 μm, by abutting rollers (not shown). At the closest position, it rotates in the forward direction, and at the time of development, an AC voltage AC is superimposed on a DC voltage of the same polarity as the toner (in the present embodiment, a negative polarity) or a DC voltage with respect to the developing sleeve 13a. By applying the developing bias voltage, non-contact reversal development is performed on the exposed portion of the photosensitive drum 10. At this time, the precision of the development interval needs to be about 20 μm or less in order to prevent image unevenness.

As described above, the developing device 13 transfers the electrostatic latent image formed on the photosensitive drum 10 by the charging by the scorotron charger 11 and the image exposure by the exposure optical system 12 in a non-contact state. Reversal development is performed with toner having the same polarity as the charge polarity of No. 10 (in this embodiment, the photosensitive drum is negatively charged, and the toner has negative polarity).

As shown in FIG. 2, the photosensitive drum 10 and a holder 20 as an exposure optical system holding member rotatably support the photosensitive drum 10 at the rear and front ends of the apparatus. Drum flanges 10A and 10B as photoconductor drum support members, and optical system flanges 120A and 1 as exposure optical system support members that support holder 20
20B is integrally formed through press-fitting or means such as screws. The photoconductor drum 10 is configured such that the drum flange 10A and the drum flange 10B serving as the photoconductor drum support member
Shaft 121 and optical system flange 1 integrated with each other
20B is rotatably supported via bearings B1 and B2, respectively.

The shaft 121 has a shaft portion 121A for holding the photosensitive drum 10, and a support shaft 130 as a shaft holding means having an engagement hole 130A is provided on the rear device board 70. The linear bearing B4 is fitted into the engagement hole 130A, and the receiving member 13
The support shaft 130 is fixed to the device substrate 70 on the rear side by screws or the like with the Oa interposed therebetween. The support shaft 130 is located at the center of the gear G2 that meshes with the drive gear G1, and rotatably supports a conductive member 131 that integrates the gear G2 via a bearing B3. On the other hand, an opening 70A is formed in the apparatus substrate 70 on the front side of the apparatus so that the photosensitive drum 10 having the exposure optical system 12 fixed to the holder 20 can be inserted and removed.

The holder 20 inserts the shaft portion 121A of the shaft 121 into the linear bearing B4 provided on the support shaft 130 with respect to the device board 70 on the rear side, and the shaft portion 121A
The engaging pin 121P inserted into the
The exposure optical system 12 is attached by regulating the angular position of the exposure optical system 12 by engaging with a V-shaped groove formed in the exposure optical system 12B. With the optical system flange 120C as a support member sandwiching the cushioning material K and pressing the front lid 120D in the axial direction, the screw 5
2 to be mounted at a predetermined position.

A coupling 10C attached to the side of a drum flange 10A serving as a photosensitive drum supporting member for supporting the photosensitive drum 10, a drive pin 131A attached to a side of a conductive member 131 integrated with a gear G2;
With the set screw 51, the drum flange 10A and the gear G
When the photosensitive drum 10 with the holding member 20 is mounted, the drum flange 1
Coupling 10C attached to the side of 0A is gear G2.
After the engagement, the conductive member 131 having the gear G2 and the photosensitive drum 10 having the drum flange 10A are aligned with the center and the outer peripheral surface. , From the side of the photosensitive drum 10 using the set screw 51
1A and the coupling 10C are fixed, and the drum flange 10A and the gear G2 are connected and fixed.

When the image forming body drive motor (not shown) is started by the start of image formation, the rotational power of the drive gear G1 is transmitted to the photosensitive drum 10 via the coupling portion by the gear G2, and the photosensitive drum 10 is moved to the position shown in FIG. , And at the same time, application of a potential to the photosensitive drum 10 is started by the charging action of the Y scorotron charger 11.
After a potential is applied to the photosensitive drum 10, exposure (image writing) by a first color signal, that is, an electrical signal corresponding to Y image data is started in the Y exposure optical system 12, and the rotation of the photosensitive drum 10 is started. By scanning, an electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface. This latent image is reversely developed in a non-contact state by the Y developing device 13, and a yellow (Y) toner image is formed on the photosensitive drum 10.

Next, the photoreceptor drum 10 places an M scorotron charger 11 on the yellow (Y) toner image.
A potential is applied by the charging action of the M exposure optical system 12
Exposure (image writing) is performed using an electrical signal corresponding to the second color signal of m, i.e., magenta (M) image data.
The magenta (M) toner image is formed on the yellow (Y) toner image by non-contact reversal development by the developing device 13.

By the same process, the cyan (C) toner image corresponding to the third color signal is further processed by the C scorotron charger 11, the exposure optical system 12 and the developing device 13, and the K scorotron charger 11. , Exposure optical system 1
A black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the second and developing units 13, and a color toner image is formed on the peripheral surface within one rotation of the photosensitive drum 10. You.

As described above, in this embodiment, Y, M,
The exposure of the organic photosensitive layer of the photoconductor drum 10 by the C and K exposure optical systems 12 is performed through a transparent substrate from the inside of the photoconductor drum 10. Therefore, the exposure of the image corresponding to the second, third, and fourth color signals can form an electrostatic latent image without being shielded by the previously formed toner image, which is preferable. Photoconductor drum 1
0 may be exposed from outside.

On the other hand, the recording paper P as a transfer material is sent out from a paper feed cassette 15 as a transfer material storage means by a feed roller (no code), fed by a feed roller (no code), and is fed by a timing roller. It is conveyed to 16.

The recording paper P is synchronized with the color toner image carried on the photosensitive drum 10 by the driving of the timing roller 16, and the recording paper P is charged by the paper charger 1 as paper charging means.
Due to the electrification of 50, the toner is attracted to the conveyor belt 14a and fed to the transfer area. The recording paper P, which is closely transported by the transport belt 14a, is moved around the photosensitive drum 10 by a transfer unit 14c as a transfer unit to which a voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied in a transfer area. The color toner images on the surface are collectively transferred to the recording paper P.

The recording paper P on which the color toner image has been transferred is
The paper is discharged by a paper separation AC neutralizer 14h as a transfer material separating unit, separated from the transport belt 14a, and transported to the fixing device 17.

As will be described in detail later, the fixing device 17 includes a resin bearing 171j as a ring-shaped holding member.
A thin magnetic fixing roller 17a as an upper (on the side of the color toner image on the recording paper P) electromagnetic induction fixing fixing roller member for fixing the color toner image;
The upper thin magnetic fixing roller 17a is composed of a lower pressing roller 47a as a pressing roller member having lower elasticity, which is paired with the upper thin magnetic fixing roller 17a. Magnetic force lines are generated inside the upper thin magnetic fixing roller 17a by electromagnetic induction. An electromagnetic induction heating unit 170, which emits and heats the thin magnetic fixing roller 17a, is disposed in contact with the thin magnetic fixing roller 17a or slightly away from the thin magnetic fixing roller 17a by about 0.5 to 2 mm.

Thin magnetic fixing roller 17a and fixing roller 4
The recording paper P is sandwiched by a nip portion N formed between the recording paper P and the color toner image on the recording paper P by applying heat and pressure. Is discharged to the tray at the top of the device.

The toner remaining on the peripheral surface of the photosensitive drum 10 after the transfer is transferred to a cleaning blade 19 provided in a cleaning device 19 as an image forming body cleaning means.
Cleaning is performed by a. The photosensitive drum 10 from which the residual toner has been removed is uniformly charged by the scorotron charger 11, and enters the next image forming cycle.

According to FIG. 3 and FIG. 5, as shown in FIG. 3, the fixing device 17 is held by a resin bearing 171j as a ring-shaped holding member, and is fixed on the upper side (recording) for fixing the toner image. A thin magnetic fixing roller 17a as a fixing roller member for electromagnetic induction fixing having elasticity of the color toner image on the paper P) and an upper thin magnetic fixing roller 17a
And a lower pressure roller 47a as a soft pressure roller member on the lower side, and a magnetic force line is generated by electromagnetic induction inside the upper thin magnetic fixing roller 17a, thereby forming the thin magnetic fixing roller 17a. An electromagnetic induction heating unit 170 as an electromagnetic induction heating body to be heated is provided in contact with the thin-plate magnetic fixing roller 17a or at a distance of about 0.5 to 2 mm.

An approximately flat wide nip portion N of about 5 to 30 mm is formed between the elastic thin sheet magnetic fixing roller 17a and the soft pressing roller 47a to fix the toner image on the recording paper P. Done.

The thin magnetic fixing roller 17a provided on the upper side and serving as a fixing roller member for electromagnetic induction fixing for fixing a toner image on a transfer material, as described in detail in FIG.
The thin elastic roller 171a as a thin cylindrical elastic body having a spring property and the magnetic elastic heat generating layer 171b (heat generating layer on the outer surface) outside the thin elastic roller 171a have an elasticity with an outer diameter of about 25 to 50 mm. It is configured as a roller member. Inside the thin magnetic fixing roller 17a, an electromagnetic induction heating unit 170 as an electromagnetic induction heating element for heating the thin magnetic fixing roller 17a is brought into contact with the thin magnetic fixing roller 17a or slightly separated by about 0.5 to 2 mm. Is arranged. The electromagnetic induction heating unit 170 includes a magnetic core JNa as a heating element and an excitation heating coil section CLa wound around the magnetic core JNa. The magnetic elastic heating layer 171b is formed by magnetic lines of force emitted from the electromagnetic induction heating unit 170. , An alternating magnetic field H is formed inside, and the magnetoelastic heating layer 171b is heated. The magnetic elastic heating layer 171b is heated by an alternating magnetic field H formed by the lines of magnetic force generated from the electromagnetic induction heating unit 170, and a roll-shaped fixing roller member for electromagnetic induction fixing that can be rapidly heated is formed. That is, the fixing roller member for electromagnetic induction fixing according to the present invention allows a current to flow through the excitation heating coil portion CLa,
An alternating magnetic field H of about 0.5 to 50 kHz is formed inside the magnetoelastic heating layer 171b by magnetic lines of force emitted from the magnetic core JNa, and the eddy current inside the magnetoelastic heating layer 171b generated by the alternating magnetic field H causes the magnetoelastic heating layer 171b. 17
1b is to be heated. The contact surface (contact surface) of the magnetic core JNa with the thin-plate magnetic fixing roller 17a is provided with five to 5
It is preferable to apply a fluorine coating of about 20 μm, and also to apply a fluorine coating to the inside (inner peripheral surface) of the thin magnetic fixing roller 17a in order to make the thin magnetic fixing roller 17a slippery. preferable.

As shown in FIG. 6, a thin magnetic fixing roller 17a as a fixing roller member for electromagnetic induction fixing for fixing a toner image on a transfer material is provided with a spring, similarly to FIG. Thin elastic roller 171a as a thin cylindrical elastic body having elasticity;
a roller member having an outer diameter of about 25 to 50 mm formed by a magnetic elastic heat generating layer 171b (a heat generating layer on the surface) outside the thin magnetic fixing roller 17a as a fixing roller member for electromagnetic induction fixing. An electromagnetic induction formed by a magnetic core JNb as a heating element and an excitation heating coil portion CLb wound around the magnetic core JNb, in contact with or slightly away from the outer peripheral surface by about 0.5 to 2 mm. You may make it arrange | position the electromagnetic induction heating unit 170A as a heating body. Outside the magnetic fixing roller 17a,
0.5 to 50 mm is applied to the inside of the magnetoelastic heating layer 171b by the lines of magnetic force generated from the electromagnetic induction heating unit 170A that is disposed slightly apart or in contact with about 0.5 to 2 mm.
An alternating magnetic field H of about Hz is formed.
1b is heated. Also in this case, the contact surface (contact surface) of the magnetic core JNb with the thin plate magnetic fixing roller 17a is provided with a 5
It is preferable to apply a fluorine coating of about 20 μm to the outside, and also to apply a fluorine coating to the outside (peripheral surface) of the thin magnetic fixing roller 17 a in order to make the thin magnetic fixing roller 17 a slippery. preferable.

As shown in FIG. 3, the pressure roller 47a as the lower pressure roller member has a rod-shaped core 471a made of, for example, stainless steel, and a silicon material, for example, provided outside the core 471a. The rubber hardness used is 20Hs ~ 7
0Hs (JIS, A rubber hardness), preferably 30Hs or more
It is configured as a soft roller having elasticity on which a rubber roller layer 471b of 40 Hs is formed. The rubber hardness is preferably the same as that of the magnetic elastic heating layer 171b mainly composed of a rubber member used on the surface of the thin plate magnetic fixing roller 17a. An elastic rubber roller having a high heat insulating property is used for the lower pressing roller 47a, and the upper magnetic elastic heating layer 171 is used.
While preventing the diffusion of heat from b to the lower pressure roller 47a, a wide nip width of 5 to 30 mm is secured.

As shown in FIG. 5, the fixing roller 17a, which is an upper thin plate-like fixing roller member, is a thin elastic roller 171a which is a thin cylindrical elastic body having a spring property, and an outer side of the thin elastic roller 171a. The layer structure is constituted by the (elastic peripheral surface) magnetoelastic heating layer 171b.

The thickness (thickness) t (mm) of the thin plate elastic roller 171a is 0.07 to 0.7, although it depends on the diameter.
For example, nickel having a thickness of about 0 mm can be used, but is preferably formed of a thin (thin-walled) metal member having a spring property using a nonmagnetic stainless steel plate or a phosphor bronze plate or the like. By using a springy metal member having a limit, the thin elastic roller 1
When the fixing member 71a is applied to the fixing device 17, the occurrence of fatigue failure due to the elastic deformation of the thin plate elastic roller 171a, which is a cylindrical elastic member, can be prevented. As the thin plate elastic roller 171a, a springy metal member such as stainless steel or iron having magnetism can be used. To prevent the occurrence of fatigue fracture due to elastic deformation, a plane bending fatigue test method (JIS,
At Z2275), in repeated several 10 ⁷ times, 140N / m
It has been experimentally confirmed that it is preferable to use a thin (thin-wall) ferromagnetic metallic member having a fatigue strength of m ² or more.

The thickness t of the thin elastic roller 171a is
(Mm), the outer diameter of the thin plate elastic roller 171a is R
(Mm), the following condition is satisfied: R / 50>t> R / 300.
In this case, the width of the nip portion N can be increased to 5 to 30 mm without deformation or breakage. Outer diameter R of thin plate elastic roller 171a
Is preferably 15 to 40 mm. t ≧ R / 5
In the case of 0, when the thin plate elastic roller 171a is too thick and applied to the fixing device 17, it does not deform into an elliptical shape and the width of the nip portion N does not become wide. There is also a disadvantage that the rate of temperature rise is slow due to a large heat capacity. When t ≦ R / 300, the thickness of the thin plate elastic roller 171a is too thin, and when applied to the fixing device 17, the strength is too low and the pressing force is insufficient, resulting in uneven fixing. Further, the heat capacity is small, which causes a temperature difference during paper passing.

The magnetoelastic heating layer 171b (surface heating layer) is made of, for example, silicon rubber (having a thermal conductivity of 1 × 10 ^−3).
J / cm · s · K) or fluoro rubber (thermal conductivity 5 × 10
^-4-based rubber as a J / cm · s · K) elastic polymeric material such as iron, chromium, nickel, a metal such as cobalt or their compounds and alloys, for example, triiron tetroxide, .gamma. Ferric oxide, chromium dioxide, manganese oxide, various ferrites, manganese-copper alloys, etc., having a particle diameter of 10 μm or less, especially 0.1 to improve dispersibility.
In order to further adjust the volume resistivity of the ferromagnetic fine particles (magnetic material) of about 1 μm to 5 to 20 mass%, Ketjen EC Black, Carbolacl, Vulcan-
2-10% by mass of conductive carbon black such as XC72, acetylene black, etc.
As a filler, a powder of a metal oxide such as silica, alumina, magnesium oxide or the like is mixed.
To 50% by mass, and the magnetic elastic heating layer 1
It is dispersed so that the volume resistivity as 71b is 10 ⁶ Ω · cm or less, preferably 10 ³ Ω · cm or less, and the thickness (wall thickness) is 0.3 to 4 mm, preferably 0.5 to 3 mm.
Use a thick one. By improving the conductivity by mixing the conductive carbon black, the temperature of the magnetoelastic heating layer 171b in the lateral direction (the direction orthogonal to the transfer material feeding direction) can be made uniform. The electromagnetic induction heating unit 170 provided inside the thin magnetic fixing roller 17a or the electromagnetic induction heating unit 1 provided outside the thin magnetic fixing roller 17a
70A, the magnetic elastic heating layer 1
It is heated by an AC magnetic field H of about 0.5 to 50 kHz formed inside 71b. In order to respond to high speed, heat is applied by powder of metal oxide such as silica, alumina and magnesium oxide as filler added to base rubber (silicon rubber or fluoro rubber) formed of the above magnetic material and conductive carbon black. A method of improving the conductivity is adopted, and the thermal conductivity is (2 to 20) × 10 ⁻³ J / cm · s · K.
It is preferable that the magnetoelastic heat generating layer 171b has a small size.
When a magnetic material, conductive carbon black, or the like is added, the rubber hardness generally tends to increase. For example, a rubber material having a normal hardness of 40 Hs is increased to near 60 Hs (JIS, A rubber hardness). The preferred rubber hardness of the magnetoelastic heating layer 171b is 5 to 60 Hs. As described above, the magnetoelastic heat generating layer 171b is formed as a magnetic material, and heat is generated near the surface layer so that the temperature of the magnetoelastic heat generating layer 171b can be increased quickly. The mixed magnetic material and filler are preferably of good conductivity, like the conductive carbon black. By doing so, the electric resistance (volume resistivity) of the magnetoelastic heating layer 171b can be easily set to a low value as the above value.

In the above, in order to generate heat in the magnetoelastic heating layer 171b, it is preferable that the thin elastic roller 171a is non-magnetic. Heat is generated up to the heat generating layer 171b, and heat can be generated.

As described above, the temperature rise is accelerated by the outer (elastic) magnetic elastic heating layer of the cylindrical elastic body of the fixing roller member for electromagnetic induction fixing, so that the warming-up time can be shortened and the lateral direction ( It is possible to provide a fixing roller member capable of achieving a uniform temperature in a direction perpendicular to the transfer material feeding direction).

As shown in FIG. 4, a thin magnetic fixing roller as a fixing roller member for electromagnetic induction fixing using a thin elastic roller 171a which is a thin cylindrical elastic body having a spring property and a magnetic elastic heating layer 171b. A ring-shaped resin bearing 171j using a heat-insulating resin material such as a fluororesin is fitted into both ends of the thin magnetic fixing roller 17a, and both ends of the thin magnetic fixing roller 17a are larger in inner diameter than the outer diameter of the thin magnetic fixing roller 17a. Bearing 1 as a holding member having
Hold at 71j. The thin magnetic fixing roller 17a integrated with the resin bearings 171j at both ends is rotatable by a bearing B5 as a bearing member fitted into the resin bearings 171j as holding members at both ends. At this time, the thin plate magnetic fixing roller 17a can be directly held by the bearings B5 at both ends. At both ends of the thin plate magnetic fixing roller 17a, receiving plates PLb made of a resin material having good slipperiness, for example, using a fluororesin or the like are provided, and the thin plate magnetic fixing roller 17a is positioned from both ends. By holding the magnetic elastic heating layer 171b mainly composed of a rubber member and having a heat insulating property by the bearing member, the thin elastic roller 171a is moved from the thin elastic roller 171a to the pressing roller 47a rather than directly holding the thin elastic roller 171a made of a metal member. This is preferable because there is no heat loss.

The pressing roller 47a is a thin plate magnetic fixing roller 1
Resin bearing 1 as a holding member provided at both ends of 7a
The core bar 471a of the pressure roller 47a is held by a bearing B6 that is disposed between the pressure rollers 71j and fitted into the left and right side plates (not numbered), and is rotatably fixed.

The center position of the bearing B5 as a bearing member at both ends, which is fitted in alignment with the center position of the resin bearing 171j at both ends, is pressed by the bearing pressing spring SPa, and the thin plate magnet is formed via the resin bearing 171j. The fixing roller 17a is pressed, and the thin plate magnetic fixing roller 17a and the pressure roller 47a are pressed. Bearing pressing spring SPa at both ends
Bearing B5 as a bearing member pressed by
Of the resin bearings 171j at both ends are the same as the center positions of the resin bearings 171j as the holding members at both ends.
And a bearing B5.

Further, a pressing spring SPA held by spring receiving plates PLA fixedly provided at both ends of the thin plate magnetic fixing roller 17a is formed by a magnetic core JNa as a heating element having an exciting coil portion CLa. An electromagnetic induction heating unit 170 serving as an electromagnetic induction heating body is mounted on the thin magnetic fixing roller 17 from inside the thin magnetic fixing roller 17a.
a is pressed against the thin sheet magnetic fixing roller 17.
A nip portion N is formed between a and the pressure roller 47a. The nip portion N is pressed by an electromagnetic induction heating unit 170 as an electromagnetic induction heating body pressed by a pressing spring SPA. The electromagnetic induction heating unit 170 is positioned with reference to the core metal 471a of the pressure roller 47a. At this time, the pressure applied to the pressure roller 4a by the pressure applied between the thin magnetic fixing roller 17a and the pressure roller 47a by the bearing pressing spring SPa (the pressure applied over the entire width of the pressure roller 47a).
7a and the pressure applied between the electromagnetic induction heating unit 170 pressed by the pressing spring SPA (the pressing roller 47).
a) is set to be small. Pressure applied between the thin plate magnetic fixing roller 17a and the pressing roller 47a by the bearing pressing spring SPa (the pressing roller 4a).
7a) is about 100 to 300N.
The pressure applied between the pressing roller 47a and the electromagnetic induction heating unit 170 pressed by the pressing spring SPA (the pressing force over the entire width of the pressing roller 47a) is about 10 to 300N, and the electromagnetic induction heating unit 170 is made of a thin plate magnetic material. Lightly contact the fixing roller 17a. Thereby, the electromagnetic induction heating unit 1 for the thin plate elastic roller 171a is provided.
70 is considered to be good. Also, the bearing pressing spring SP
Due to the pressing force of the electromagnetic induction heating unit 170 having a pressing force smaller than the pressing force of a, the deformation of the thin plate elastic roller 171a is small even when a thin wall is used, and a stable pressure (pressing force) is obtained.
Then, the nip portion N having a wide and stable width is obtained (the nip portion N is stably formed), and stable and good fixing can be achieved. Further, in the direction perpendicular to the direction in which the transfer material passes, the transverse direction (axial direction, perpendicular to the feed direction of the transfer material) of the exciting coil portion CLa of the magnetic core JNa as the heating element provided in the electromagnetic induction heating unit 170 is provided. Direction) width L
21 is set to be smaller than the width L3 of the nip portion N set inside both ends of the pressure roller 47a. This prevents the heat from the magnetic core JNa in the portion of the exciting coil portion CLa from being released to the end of the pressure roller 47a, thereby preventing an abnormal temperature rise at the end of the nip N.

A pressure roller 47a rotatably held by a bearing B6 fitted into the left and right side plates (no reference numeral).
The gear G is attached to one end of the core metal 471a.
12, a gear G22 driven and rotated by the fixing drive motor M1 is connected to the gear G12, and the pressure roller 47a is rotated by the driving of the fixing drive motor M1, and is pressed against the pressure roller 47a. The thin magnetic fixing roller 17a is driven to rotate. By the driven rotation, the rotation of the thin-plate magnetic fixing roller 17a is made uniform, and uneven fixing is prevented.

As described above, the thin elastic roller 171a having a spring property is applied to the fixing roller member for electromagnetic induction fixing together with the magnetic elastic heating layer 171b, and the pressing force with the elastic pressing roller 47a is reduced. , The elastic force of the thin elastic roller 171a of the thin magnetic fixing roller 17a and the electromagnetic induction heating unit 17 pressed by the pressing spring SPA
Received at zero pressing force. Thereby, the thin plate elastic roller 1
The thin plate elastic roller 171 a is expanded by an elliptical shape (a nip portion N pressed by the pressing plate PVa is flat) without plastic deformation, and is pressed by the electromagnetic induction heating unit 170.
(Actually, on the surface of the magnetic elastic heating layer 171b on the surface of the thin plate elastic roller 171a) against the soft rubber roller layer 471b of the pressing roller 47a.
A wide nip N of 30 mm is formed. 5-30m
A wide nip portion N of m allows good fixing of the toner image.

As described above, the thin plate magnetic fixing roller 17
Even if a is small, the nip width can be made as wide as 5 to 30 mm, so that a fixing device with energy saving and a short warm-up time can be realized. Further, the large curvature (the radius of the curved surface is small) of the pressure roller 47a at the outlet of the nip portion N improves the separation from the recording paper P.

In the above, the thin plate elastic roller 171
a (cylindrical elastic body) and a magnetic elastic heat generating layer 171b, the thin magnetic fixing roller 1 opposed to a pressure roller 47a fixed and rotatably provided.
7a (the fixing roller member for electromagnetic induction fixing) is pressed by the bearing pressing springs SPa at both ends, and the thin plate magnetic fixing roller 1 is pressed.
When the supporting member 7a is supported at both ends, it receives the pressing force of the pressing roller 47a which is narrower than the thin magnetic fixing roller 17a, so that the pressing force at the nip portion N becomes uneven or the end portion of the thin magnetic fixing roller 17a. Is large, and the thin-plate magnetic fixing roller 17a becomes uneven in rotation and causes uneven fixing.However, the above-described fixing roller member for electromagnetic induction fixing is pressed against the nip portion N of the fixing device 17, By providing an electromagnetic induction heating body having a heating element, the sliding of the electromagnetic induction heating body with respect to the cylindrical elastic body is good, and the deformation of the cylindrical elastic body is small even when a thin wall is used. The width of the nip portion can be obtained (the nip portion can be formed stably), stable and good fixing can be performed, and a fixing device with a reduced warm-up time can be realized. In addition, a fixing device with good transfer material separability can be provided.

As the fixing roller member for electromagnetic induction fixing described above, as shown in FIG.
a between the elastic heat insulating layer 17a and the magnetic elastic heat generating layer 171b.
1d may be provided to form the thin-plate magnetic fixing roller 17b.

The elastic heat insulating layer 171d is made of, for example, silicon rubber (having a thermal conductivity of 1 × 10 ⁻³ J / c) having a thickness (wall thickness) of 0.2 to 2 mm, preferably 0.5 to 1.5 mm.
m · s · K) or fluoro rubber (thermal conductivity 5 × 10 ⁻⁴ J /
(cm · s · K) or the like, and is formed of a base rubber as a resilient polymer material that transmits magnetic lines of force and transmits magnetic lines of force. For the elastic heat insulating layer 171d, in order to cope with a high speed, heat conduction is performed by mixing a metal oxide powder such as silica, alumina, magnesium oxide or the like as a filler with a base rubber (silicone rubber or fluorine rubber) as an elastic polymer material. It is preferable to use a base layer having a thermal conductivity of (1 to 10) × 10 ⁻³ J / cm · s · K.

By providing the elastic heat insulating layer 171d,
The thin magnetic fixing roller 17a as an upper fixing roller member for electromagnetic induction fixing is formed as a softer roller member, and a softer and wider nip portion N is secured between the thinner magnetic fixing roller 17a and the lower pressing roller 47a. Particularly, the fixability of the color toner image at the time of forming a color image is improved.

Magnetic lines of force generated from the electromagnetic induction heating unit 170 provided inside the thin magnetic fixing roller 17a or the electromagnetic induction heating unit 170A provided outside provide 0.5 to 50 kHz formed inside the magnetic elastic heating layer 171b. The magnetoelastic heat generating layer 171b is heated by the AC magnetic field H of a certain degree.

As described above, the temperature rise of the fixing roller member is accelerated, the warming-up time is shortened, and the fixing roller member at the nip portion at the time of sheet passing is in the lateral direction (the direction orthogonal to the transfer material feeding direction). Thus, it is possible to provide a fixing device for quick start fixing capable of instantaneous heating without causing fixing unevenness and achieving uniform temperature.

[0063]

According to the first aspect of the present invention, the temperature rise is accelerated by the surface magneto-elastic heating layer, the warming-up time is shortened, and the temperature in the lateral direction (the direction orthogonal to the transfer material feeding direction) is increased. And a fixing roller member for electromagnetic induction fixing that achieves uniformity can be provided.

According to the second or third aspect, the temperature of the fixing roller member for electromagnetic induction fixing is accelerated, the warming-up time is shortened, and the fixing roller member for electromagnetic induction fixing at the nip portion when paper is passed. In this case, it is possible to provide a fixing device for quick start fixing capable of instantaneous heating without causing unevenness in fixing by achieving uniform temperature in a lateral direction (a direction orthogonal to a feeding direction of the transfer material).

[Brief description of the drawings]

FIG. 1 is a sectional view of a color image forming apparatus showing an embodiment of an image forming apparatus using a fixing device according to the present invention.

FIG. 2 is a side sectional view of the image forming body of FIG. 1;

FIG. 3 is a schematic sectional view of a fixing device using a fixing roller member for electromagnetic induction fixing.

FIG. 4 is a schematic side view showing a pressing structure of the fixing device.

FIG. 5 is a diagram illustrating a layer configuration and a function of a fixing roller member for electromagnetic induction fixing.

FIG. 6 is a diagram illustrating another example of an electromagnetic induction heating body that heats a fixing roller member for electromagnetic induction fixing.

FIG. 7 is a diagram illustrating another example of a layer configuration of a fixing roller member for electromagnetic induction fixing.

[Explanation of symbols]

 Reference Signs List 10 photoconductor drum 11 scorotron charger 12 exposure optical system 13 developing device 17 fixing device 17a, 17b thin magnetic fixing roller 47a pressing roller 170, 170A electromagnetic induction heating unit 171a thin elastic roller 171b magnetoelastic heating layer 171d elastic heat insulating layer 171j Resin bearing B5 Bearing bearing CLa, CLb Exciting coil H AC magnetic field JNa, JNb Magnetic core N Nip P Recording paper PLA Spring receiving plate SPA Pressing spring SPa Bearing pressing spring

Claims (3)

[Claims] 1. A fixing roller member for electromagnetic induction fixing, comprising: an electromagnetic induction heating element; a thin cylindrical elastic element; and a magnetic elastic heating layer outside the cylindrical elastic element. 2. A fixing device for fixing a toner image on a transfer material to the transfer material by heating and pressurizing, wherein: an electromagnetic induction heating body; a thin cylindrical elastic body; A roller having a magnetic elastic heating layer to form a fixing roller member for electromagnetic induction fixing, and a pressure roller having elasticity opposed to the fixing roller member for electromagnetic induction fixing and the fixing roller member for electromagnetic induction fixing; A nip portion for fixing the toner image on the transfer material between the electromagnetic induction fixing fixing roller member and the pressure roller member by deforming the cylindrical elastic body. A fixing device. 3. The fixing device according to claim 2, wherein the fixing roller member for electromagnetic induction fixing is held by a bearing member circumscribing the magnetoelastic heating layer.