JP2007156363A - Roller for fixing, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller for fixing excellent in responsiveness in temperature control, a fixing device equipped with the roller for fixing and an image forming apparatus. <P>SOLUTION: A fixing roller (roller for fixing) 21 has: a roller main body 210; a heating layer (surface heater) 213 provided on the outer peripheral surface (surface) of the roller main body 210; an elastic layer 214 provided on the outer peripheral surface (surface) of the heating layer 213, and a surface layer 215 provided on the outer peripheral surface (surface) of the elastic layer 214. The roller main body 210 is equipped with: a cylinder 211; a cylindrical rotary shaft 216 fixed in the cylinder 211; and an insulating layer 212 provided on the outer peripheral surface of the cylinder 211. The heating layer 213 has a self temperature control function, and is composed by containing carbon-based substance which is reformed so as to improve contact with polymer (base material) in the polymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing roller, a fixing device, and an image forming apparatus.

In an image forming apparatus such as a printer, a copy machine, a facsimile machine, etc., a fixing device for fixing the toner image on a recording sheet by heating and pressurizing a recording medium carrying a toner image formed with toner in an unfixed state. Some are equipped with.
In such a fixing device, for example, a recording material on which a toner image is transferred is passed between a fixing roller incorporating a halogen heater (heating means) and a pressure roller, and heating and pressure are applied by two rollers. Thus, the toner image is fixed on the recording material (see, for example, Patent Document 1).

However, since the halogen heater is installed at substantially the same position as the rotation shaft of the fixing roller and heats the roller body using air as a medium, there is a problem that heat loss occurs, that is, thermal efficiency is low.
In addition, this halogen heater has a problem that quick heating cannot be performed and a problem that power consumption is high because it emits more visible light that does not contribute to heating than infrared rays effective for heating.
Further, since this halogen heater does not have a self-temperature control function, there is a problem that a thermostat, a fuse, or the like must be used together in order to keep the temperature of the fixing roller constant.

JP 2004-294737 A

  An object of the present invention is to provide a fixing roller excellent in temperature control responsiveness, a fixing device including the fixing roller, and an image forming apparatus.

Such an object is achieved by the present invention described below.
The fixing roller of the present invention is a fixing roller used in a fixing process for fixing an unfixed image carried on a recording medium to the recording medium,
The roller body,
An elastic layer provided on the outer peripheral surface side of the roller body;
A heating element that has a self-temperature control function, generates heat when energized, and heats the fixing roller;
The heating element is characterized in that the polymer contains a carbon-based material that has been subjected to a modification treatment that improves adhesion to the polymer.
As a result, a fixing roller having excellent temperature control responsiveness can be obtained.

In the fixing roller of the present invention, it is preferable that the modification treatment is a treatment in which a compound having a reactive group capable of reacting with the polymer is covalently bonded or coordinated to the carbonaceous material.
Thereby, a compound having a reactive group can be imparted to the carbon-based material with a strong binding force, and this compound can be prevented from easily leaving the carbon-based material. In addition, since the graphene structure that contributes to the characteristics (high conductivity) of the carbon-based material is not destroyed, a heating element with better temperature control responsiveness can be obtained.

In the fixing roller of the present invention, the modifying treatment may be performed by reacting a precursor of a second polymer having high compatibility with the polymer on the surface of the carbon-based material, and obtaining the second polymer. A treatment for coating the surface of the carbon-based material is preferable.
As a result, the second polymer can be imparted to the carbon-based material by a strong anchoring force (anchor effect), and the second polymer can be prevented from easily leaving the carbon-based material. it can. In addition, since the graphene structure that contributes to the characteristics (high conductivity) of the carbon-based material is not destroyed, a heating element with better temperature control responsiveness can be obtained.

In the fixing roller of the present invention, the content of the carbonaceous material in the heating element is preferably 1 to 30 wt%.
By setting the content of the carbon-based substance in the heating element within the above range, when a voltage is applied, the electrical resistance in the initial state of the heating element can be sufficiently reduced, while on the other hand, it is abrupt at a predetermined temperature. An increase in electrical resistance can be ensured.

In the fixing roller of the present invention, it is preferable that the heating element is provided in a layered manner on the outer peripheral surface of the roller body.
Thereby, it is possible to prevent the occurrence of temperature unevenness on the outermost surface of the fixing roller, that is, to make the temperature distribution uniform. Thereby, an unfixed image can be stably fixed on the recording medium, that is, the print quality can be improved.

In the fixing roller of the present invention, the heating element is provided in contact with the elastic layer,
It is preferable that the polymer is highly compatible with the constituent material of the elastic layer.
Thereby, the adhesiveness of a layered heat generating body and an elastic layer improves, and it can prevent suitably peeling between these.
In the fixing roller of the present invention, the roller body has a cylindrical shape,
It is preferable that the heating element is provided so as to contact an inner peripheral surface of the roller body.
As a result, the electrode configuration for energizing the heating element can be simplified, that is, the structure of the fixing device can be simplified, and the manufacturing cost can be reduced.

The fixing device of the present invention includes a fixing roller and a pressure roller pressed against the fixing roller, and allows a recording medium carrying an unfixed image to pass between the fixing roller and the pressure roller. A fixing device for fixing the unfixed image on the recording medium,
At least one of the fixing roller and the pressure roller is constituted by the fixing roller of the present invention.
As a result, it is possible to provide a fixing device with excellent temperature control responsiveness and high reliability.
The image forming apparatus of the present invention includes the fixing device of the present invention.
Accordingly, it is possible to provide an image forming apparatus having excellent temperature control responsiveness and high reliability.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a fixing roller, a fixing device, and an image forming apparatus of the invention will be described with reference to the accompanying drawings.
[Image forming apparatus]
First, the configuration of the image forming apparatus of the present invention will be described.
FIG. 1 is an overall configuration diagram of an image forming apparatus of the present invention provided with a fixing device of the present invention.
In the apparatus main body 2 of the image forming apparatus 1, an image carrier 3 composed of a photosensitive drum is disposed. The image carrier 3 is rotationally driven in the direction of the arrow shown by a driving unit (not shown).

Around the image carrier 3, a charging device 4 for uniformly charging the image carrier 3 along its rotation direction, and an exposure device for forming an electrostatic latent image on the image carrier 3 5, a rotary developing device 6 for developing an electrostatic latent image, and an intermediate transfer device 7 for primary transfer of a monochromatic toner image formed on the image carrier 3.
In the rotary developing device 6, a yellow developing device 6Y, a magenta developing device 6M, a cyan developing device 6C, and a black developing device 6K are mounted on a support frame 8, and the support frame 8 is rotationally driven by a drive motor (not shown). It is configured.

The plurality of developing devices 6Y, 6C, 6M, and 6K are selectively rotated so that the developing roller 6a of one developing device is opposed to the image carrier 3 every rotation of the image carrier 3. Has been.
Each of the developing devices 6Y, 6C, 6M, and 6K has a toner storage portion that stores toner of each color.

The intermediate transfer device 7 is disposed so as to face the image carrier 3 on the back surface of the intermediate transfer belt 11, the driving roller 9 and the driven roller 10, the intermediate transfer belt 11 driven in the direction of the arrow by the two rollers. A primary transfer roller 12, a transfer belt cleaner 13 for removing residual toner on the intermediate transfer belt 11, and a drive roller 9 are arranged to face the four-color full-color image formed on the intermediate transfer belt 11 as a recording medium ( And a secondary transfer roller 14 for transferring onto paper or the like.
A paper feed cassette 15 is disposed at the bottom of the apparatus main body 2, and a recording medium in the paper feed cassette 15 is discharged through a pickup roller 16, a recording medium conveyance path 17, a secondary transfer roller 14, and a fixing device 19. It is configured to be conveyed to the tray 20.

Next, the operation of the image forming apparatus configured as described above will be described.
When an image forming signal is input from a computer (not shown), the image carrier 3, the developing roller 6 a of the developing device 6 and the intermediate transfer belt 11 are rotationally driven. First, the outer peripheral surface of the image carrier 3 is charged by the charging device 4. The exposure device 5 selectively exposes the outer peripheral surface of the uniformly charged image carrier 3 according to the image information of the first color (for example, yellow) so that the electrostatic latent image of yellow An image is formed.

  At the position of the latent image formed on the image carrier 3, the yellow developing device 6 </ b> Y rotates and the developing roller 6 a comes into contact therewith, whereby the yellow electrostatic latent image toner image is formed on the image carrier 3. Next, the toner image formed on the image carrier 3 is transferred onto the intermediate transfer belt 11 by the primary transfer roller 12. At this time, the secondary transfer roller 14 is separated from the intermediate transfer belt 11.

In accordance with the second color, the third color, and the fourth color of the image formation signal, the above processing is repeated to form a latent image, develop, and transfer by one rotation of the image carrier 3 and the intermediate transfer belt 11, thereby forming an image. Four color toner images corresponding to the contents of the signals are superimposed and transferred on the intermediate transfer belt 11.
Then, at the timing when this full-color image reaches the secondary transfer roller 14, the recording medium is supplied from the conveyance path 17 to the secondary transfer roller 14, and at this time, the secondary transfer roller 14 is pressed against the intermediate transfer belt 11. A secondary transfer voltage is applied, and the full color toner image (unfixed image) on the intermediate transfer belt 11 is transferred onto the recording medium.

Then, by passing the recording medium carrying the toner image between the fixing roller 21 and the pressure roller 22, that is, through the fixing device 19, the toner image is heated and pressed and fixed on the recording medium. The toner remaining on the intermediate transfer belt 11 is removed by the transfer belt cleaner 13.
In the case of double-sided printing, the recording medium exiting the fixing device 19 is switched back so that the trailing edge is the leading edge, and is supplied to the secondary transfer roller 14 via the double-sided printing conveyance path 23, and the intermediate medium. The full color toner image on the transfer belt 11 is transferred onto the recording medium, and is again heated and pressed by the fixing device 19 to be fixed.
The fixing device 19 includes a fixing roller (fixing roller of the present invention) 21 having a heat source and a pressure roller 22 pressed against the fixing roller 21. A line connecting the axis of the fixing roller 21 and the axis of the pressure roller 22. Are arranged to have an angle of θ from the horizontal line. Note that 0 ° ≦ θ ≦ 30 °.

[Fixing device]
Hereinafter, the fixing device of the present invention will be described in detail.
2 to 6 show details of the fixing device shown in FIG. 1, FIG. 2 is a perspective view showing a partially broken section of the fixing device of the present invention, and FIG. 3 shows the fixing device shown in FIG. 4 is a side view showing a mounting state of the pressure roller and the fixing roller shown in FIG. 2, FIG. 5 is a sectional view of the pressure roller shown in FIG. 2, and FIG. FIG. 3 is a cross-sectional view of the fixing roller shown in FIG. 2.

As shown in FIGS. 2 and 3, a fixing roller 21 is rotatably mounted in the housing 24 of the fixing device 19, and a driving gear 28 is connected to one end of the fixing roller 21.
A pressure roller 22 is rotatably mounted facing the fixing roller 21. The axial length of the pressure roller 22 is shorter than that of the fixing roller 21, and a bearing 25 is provided in the empty space, and both ends of the pressure roller 22 are supported by the bearing 25.

A pressure lever 26 is rotatably provided on the bearing 25, and a pressure spring 27 is disposed between one end of the pressure lever 26 and the housing 24, whereby the pressure roller 22 and the fixing roller 21 are added. It is configured to be pressed (pressure contact).
Support shafts 29 and 30 are provided on both side surfaces of the housing 24, and a separation member 31 on the fixing roller 21 side and a separation member 32 on the pressure roller 22 side rotate on the support shafts 29 and 30, respectively. Mounted freely. Accordingly, the peeling members 31 and 32 are disposed on the downstream side of the nip portion N (see FIG. 4) in the recording medium conveyance direction in the axial direction between the fixing roller 21 and the pressure roller 22.

As shown in FIG. 5, the pressure roller 22 includes a metal cylinder 221, a rotation shaft 222 fixed to the cylinder 221, a bearing 25 that supports the rotation shaft 222, and an outer periphery of the cylinder 221. It has the elastic layer 223 comprised with the provided silicone rubber etc., and the surface layer 224 coat | covered on the surface of the elastic layer 223.
The surface layer 224 is made of, for example, fluorine rubber, fluorine resin (for example, pertetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA)), or the like. By providing the surface layer 224 made of such a material, it is possible to prevent the toner from adhering to the pressure roller 22 (surface layer 224).
In addition, the rotating shaft 222 is not limited to being configured by a hollow body as illustrated, and may be configured by a solid body.

As shown in FIG. 6, the fixing roller 21 includes a roller main body 210, a heat generating layer (planar heater) 213 provided on the outer peripheral surface (surface) of the roller main body 210, and an outer peripheral surface (surface) of the heat generating layer 213. It has an elastic layer 214 provided and a surface layer 215 provided on the outer peripheral surface (surface) of the elastic layer 214.
The roller body 210 includes a cylinder 211, a cylindrical rotating shaft 216 fixed in the cylinder 211, and an insulating layer 212 provided on the outer peripheral surface of the cylinder 211.
With such a configuration, the respective parts rotate together around the rotation shaft 216 as a center (axis), and the surface (outer peripheral surface) of the fixing roller 21 is warmed by the heat generating layer (layered heat generating element) 213. ing.

The cylinder 211 and the rotating shaft 216 are each made of a material having good thermal conductivity, such as a metal material.
The insulating layer 212 can be made of, for example, a heat resistant resin such as polyimide resin, SiO ₂ or the like. The average thickness of the insulating layer 212 is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 30 to 50 μm.

The cylindrical body 211 and the insulating layer 212 are not limited to those obtained by joining separate bodies, and may be integrally formed using, for example, an insulating material. Moreover, the rotating shaft 216 is not limited to a hollow body, and can be formed of a solid body.
The heat generating layer 213 is formed over the entire circumference of the surface of the insulating layer 212. The heat generating layer 213 generates heat when energized to heat the fixing roller 21.

The present invention is characterized by the constituent material of the heat generating layer 213. This point (feature) will be described in detail later.
The average thickness (t in FIG. 6) of the heat generating layer 213 is not particularly limited, but is preferably about 10 to 500 μm, and more preferably about 50 to 300 μm. If the heat generating layer 213 is too thin, it is difficult to form a uniform film, which may cause film defects. Further, if the heat generating layer 213 is too thick, cracks may occur due to the heat cycle.

In addition, brush electrodes 217 as electrode portions for energizing the heat generating layer 213 are provided at both ends in the rotation axis direction of the heat generating layer 213 (see FIG. 3). Accordingly, the heat generation layer 213 can be reliably energized regardless of whether the fixing roller 21 is rotating.
As shown in FIG. 6, the elastic layer 214 is formed over the entire circumference of the surface of the heat generating layer 213.

  The constituent material of the elastic layer 214 is not particularly limited. For example, silicone rubber, fluorine rubber, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, acrylic rubber, ethylene-propylene Various rubber materials such as rubber, hydrin rubber, urethane rubber (especially vulcanized), styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, Examples include elastic materials such as various types of thermoplastic elastomers such as fluororubber-based and chlorinated polyethylene, and one or more of them can be used in combination.

Among these, as a constituent material of the elastic layer 214, a material mainly composed of silicone rubber is preferable. Silicone rubber is particularly preferable because it is excellent in heat resistance and excellent in elasticity (flexibility).
The thickness of the elastic layer 214 is preferably smaller than the thickness of the elastic layer 223 of the pressure roller 22. As a result, as shown in FIG. 4, a nip portion N having a concave shape on the pressure roller 22 side can be reliably formed.

Specifically, the average thickness of the elastic layer 214 is not particularly limited, but is preferably about 0.1 to 3 mm, and more preferably about 0.5 to 1.5 mm.
The surface (outer surface) of the elastic layer 214 is covered with a surface layer (peeling layer) 215 formed along the entire circumference.
The surface layer 215 is mainly composed of a resin material. The resin material is not particularly limited, and examples thereof include fluorine-based resins such as pertetrafluoroethylene (PTFE) and tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA). Among these, One kind or a combination of two or more kinds can be used. Thereby, it is possible to prevent the toner from adhering to the fixing roller 21 (surface layer 215).

The average thickness of the surface layer 215 is not particularly limited, but is preferably about 1 to 100 μm, and more preferably about 30 to 80 μm.
In the present invention, the heat generating layer 213 has a self-temperature control function, and contains a carbon-based material that has been subjected to a modification treatment for improving the adhesion to the polymer in the polymer (base material). is there.

Here, the self-temperature control function means that when a voltage is applied, a current flows through the heat generating layer 213. At this time, the temperature of the heat generating layer 213 increases due to Joule heat. That is, the amount of current flowing through the heat generating layer 213 is suppressed, and the predetermined temperature is maintained.
In the heat generation layer 213, in the initial state (voltage non-applied state), the carbon-based substances are in direct contact with each other or are in an extremely close state, so that a current flows by applying a voltage. On the other hand, when heat is generated by energization and the temperature of the heat generating layer 213 increases, the polymer thermally expands, the carbon-based material moves following this, and the carbon-based materials are separated from each other or their separation distance is increased. As a result, the electrical resistance increases rapidly and the amount of current flowing through the heat generating layer 213 is suppressed.

  The surface of the carbon-based substance is inactive, and adhesion with various polymers (resin materials) is low. For this reason, if the heat generating layer is formed by mixing the carbon-based material into the polymer as it is, when the polymer is thermally expanded, the movement of the carbon-based material following this hardly occurs, and the heat generating layer reaches a predetermined temperature. Even so, a rapid increase in electrical resistance cannot be expected. That is, such a heat generating layer is inferior in temperature control responsiveness.

  On the other hand, in the present invention, the carbon-based material is previously subjected to a modification treatment for improving the adhesion with the polymer, and this is mixed with the polymer to form the heat generating layer 213. Is firmly fixed to the polymer (base material). For this reason, the movement of the carbonaceous material surely follows the thermal expansion of the polymer, and when the heat generating layer 213 reaches a predetermined temperature, the electrical resistance rapidly increases. That is, the heat generation layer 213 is excellent in temperature control responsiveness.

In addition, by preliminarily modifying the carbon-based material, dispersibility in the polymer is improved, thereby preventing temperature unevenness in the heat generating layer (heat generating body) 213.
It does not specifically limit as a polymer used as a base material, Various thermoplastic resins and various thermosetting resins can be used.

Examples of the thermoplastic resin include polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, modified polyolefins, polyamides (for example, nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12). , Nylon 6-12, nylon 6-66, aramid resin), thermoplastic polyimide, aromatic polyester and other liquid crystal polymers, polyacrylonitrile, polyphenylene oxide, polyphenylene sulfide, polycarbonate, polymethyl methacrylate, polyethylene terephthalate (PET), polybutylene Polyester such as terephthalate (PBT) and polyphenylene terephthalate, polyether, polyetheretherketone, polyetherimide, polyaceter , Styrene, polyolefin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluororubber, or the like various thermoplastic elastomers such as chlorinated polyethylene and the like.
On the other hand, examples of the thermosetting resin include an epoxy resin, a phenol resin, a urea resin, a melamine resin, a polyester (unsaturated polyester) resin, a polyimide resin, a silicone resin, and a polyurethane resin.

In the case of this embodiment, it is preferable that the polymer has excellent compatibility with the constituent material of the elastic layer 214. Thereby, the adhesiveness of the heat generating layer 213 and the elastic layer 214 is improved, and separation between them can be suitably prevented.
As described above, a material mainly composed of silicone rubber is preferably used as the constituent material of the elastic layer 214. In this case, the polymer includes polyether ether ketone, polyimide resin, silicone resin (organopolysiloxane). ) Having at least one of them as a main component is preferably used.

On the other hand, examples of the carbon-based material include carbon fiber, graphite, carbon black, fullerene, carbon nanotube, cup stack, carbon nanocor, and the like, and one or more of these may be used in combination. it can.
Further, as the modification treatment, for example, a compound having a reactive group capable of reacting with the polymer is chemically bonded (adsorbed) to the carbonaceous material, such as a covalent bond, a coordinate bond, or an ionic bond, A treatment of coating the surface of the carbon-based material with a polymer (second polymer) having high compatibility with the polymer can be mentioned.

Among these, the modification treatment includes: I: a treatment in which a compound having a reactive group capable of reacting with a polymer is covalently or coordinated (grafted) with a carbon-based material, or II: a second polymer. The precursor is preferably reacted on the surface of the carbon-based material, and the surface of the carbon-based material is coated with the obtained second polymer.
According to these methods, a compound having a reactive group or the second polymer can be imparted to a carbon-based material by a strong binding force (in the case of I) or a strong anchoring force (in the case of II). And these can be prevented from easily leaving the carbonaceous material. In addition, since the graphene structure that contributes to the characteristics (high conductivity) of the carbon-based material is not destroyed, the heat generating layer 213 with more excellent temperature control responsiveness can be obtained.

  In the case of I, A: As a method for covalently bonding a compound having a reactive group, for example, a terminal carbon of a carbon-based substance is oxidized to introduce a carboxyl group, and this carboxyl group has a reactive property. Examples include a method of bonding a compound having a group, and B: a method of coordinating a compound having a reactive group, for example, as a compound having a reactive group, such as ferrocene and nickelocene introduced with a reactive group. And a method of bonding the metal complex derivative using a ligand exchange reaction.

  The content in the heat generation layer 213 of the carbon-based material (modified carbon-based material) subjected to such a modification treatment is not particularly limited, but is preferably about 0.01 to 30 wt%, More preferably, it is about 0.5 to 20 wt%. By setting the content of the carbonaceous material in the heat generating layer 213 in the above range, when a voltage is applied, the electric resistance in the initial state of the heat generating layer 213 can be sufficiently reduced, while at a predetermined temperature. An abrupt increase in electrical resistance can be ensured.

Note that by appropriately setting the composition of the constituent material of the heat generating layer 213, the resistance value in the initial state (voltage non-applied state) of the heat generating layer 213 and the temperature at which self-temperature control is possible can be adjusted. For example, the resistance value in the initial state of the heat generating layer 213 can be adjusted by setting the content of the carbonaceous material in the heat generating layer 213, the type of polymer, and the like. In addition, for example, the temperature at which self-temperature control is possible can be adjusted by setting the content of the carbonaceous material in the heat generating layer 213, the thermal expansion of the polymer, and the like.
Such a heat generating layer 213 prepares a liquid material containing, for example, a polymer serving as a base material or a precursor thereof and a surface-modified carbon-based material, and supplies the liquid material to the outer peripheral surface of the roll body 210. Then, a liquid film can be formed, and the liquid film can be formed by performing a predetermined treatment (for example, drying, heat treatment, ultraviolet irradiation, etc.).

Examples of the solvent (or dispersion medium) used for the preparation of the liquid material include methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), ketone solvents such as cyclohexanone, methanol, Alcohol solvents such as ethanol, isopropanol, ethylene glycol, diethylene glycol (DEG), glycerin, diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP) ), Ether solvents such as anisole, diethylene glycol dimethyl ether (diglyme), diethylene glycol ethyl ether (carbitol), methyl acetate, ethyl acetate, vinegar Ester solvents such as butyl and ethyl formate, cellosolve solvents such as methyl cellosolve, ethyl cellosolve and phenyl cellosolve, aliphatic hydrocarbon solvents such as hexane, pentane, heptane and cyclohexane, toluene, xylene, benzene, trimethylbenzene, tetra Aromatic hydrocarbon solvents such as methylbenzene, aromatic heterocyclic solvents such as pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone, N, N-dimethylformamide (DMF), N, N-dimethylacetamide ( Amide solvents such as DMA), halogen compound solvents such as dichloromethane, chloroform, 1,2-dichloroethane, sulfur compound solvents such as dimethyl sulfoxide (DMSO), sulfolane, acetonitrile, propionitrile, acrylonitrile Nitriles etc., or a mixed solvent thereof.
Examples of methods for supplying the liquid material include various methods such as dip coating, spin coating, slit coating, cap coating, dispenser, spray coating, roll coating, screen printing, and ink jet printing. A coating method is preferably used.

Next, another configuration example of the fixing roller 21 will be described.
FIG. 7 is a cross-sectional view of a fixing roller of another configuration example.
Hereinafter, the fixing roller shown in FIG. 7 will be described with a focus on differences from the fixing roller shown in FIG. 6, and the description of the same matters will be omitted.
The fixing roller 21 shown in FIG. 7 is the same as the fixing roller 21 shown in FIG.
That is, the fixing roller 21 shown in FIG. 7 includes a heat generating block 218 provided as a heat generating member so as to come into contact (sliding contact) with the inner peripheral surface of the roller main body 210 (rotating shaft 216).

In the fixing roller 21 as described above, the heating element is provided in the vicinity of the outermost surface of the fixing roller 21 or in direct contact with the inner peripheral surface of the roller main body 210. The fixing device 19 can stably maintain a state of high thermal efficiency.
Also, with such a configuration, it is possible to quickly warm the surface of the fixing roller 21 (that is, quick heat). Thereby, the fixing device 19 can surely shorten the activation time.

Also, as shown in FIG. 6, the overall shape of the heating element is cylindrical (layered), thereby preventing temperature unevenness on the outermost surface of the fixing roller 21, that is, making the temperature distribution uniform. be able to. Thereby, an unfixed image can be stably fixed on the recording medium, that is, the print quality can be improved.
Further, by making the heating element into a block shape as shown in FIG. 7, the electrode configuration for energizing the heating element can be simplified, that is, the structure of the fixing device 19 can be simplified. Manufacturing costs can be reduced.

Further, in the fixing device 19, power consumption can be suppressed as compared with a conventional case where a halogen heater is used as a heat source (heating means). In the fixing device 19, the power consumption can usually be about 200 to 300 W.
For example, even when a small sheet such as a postcard passes through the fixing device 19, the end of the fixing roller 21 in the central axis direction is excessively heated because the heating element has a self-temperature control function. Is prevented. As a result, the standby time by adjusting the temperature of the fixing roller 21 can be omitted, so that continuous paper feeding (continuous printing) can be performed.

Further, the fixing device 19 is excellent in safety because the heating element has a self-temperature control function, so that the fixing device 19 is prevented from generating heat above a predetermined temperature.
Moreover, instead of the brush electrode 217, the electrode portion of the heating element may be constituted by, for example, a bearing electrode or a roller electrode. For example, the bearing electrode tends to be more durable than the brush electrode 217.

The fixing roller, the fixing device, and the image forming apparatus according to the present invention have been described above with reference to the illustrated embodiment. However, the present invention is not limited to this.
For example, each part constituting the fixing roller, the fixing device, and the image forming apparatus can be replaced with an arbitrary configuration that can exhibit the same function. Moreover, arbitrary components may be added.
In the above-described embodiment, the case where the fixing roller of the present invention is applied to the fixing roller has been described as a representative. However, the fixing roller of the present invention may be applied to a pressure roller. You may apply to both of a roller.

Next, specific examples of the present invention will be described.
1. Manufacturing of fixing device (Example 1)
<1> First, an iron cylinder (outer diameter 30 mm × length 300 mm) was prepared, and an iron cylindrical rotating shaft was joined inside. <2> Next, polyimide resin was applied to the outer peripheral surface of the cylinder. An insulating layer (average thickness 40 μm × length 300 mm) was formed. This obtained the roller main body.

<3> Next, a heat generating layer (average thickness 100 μm × length 300 mm) was formed on the outer peripheral surface of the insulating layer.
<3-1> First, carbon fiber (made by Nippon Carbon Co., Ltd.) was prepared.
The carbon fibers had an average length of 100 μm and an average diameter of 10 μm.
Next, this carbon fiber was oxidized by heat treatment to introduce carboxyl groups at the ends thereof.
Next, the carbon fiber into which the carboxyl group was introduced was mixed with ethylenediamine and heated at 100 ° C. for 1 hour. Thereby, the carboxyl group and ethylenediamine were reacted. As a result, the carbon fiber was modified.

<3-2> Next, the carbon fiber subjected to the modification treatment is mixed with a solution prepared by dissolving polyamic acid (polyimide resin precursor) in triethylene glycol dimethyl ether so as to be 20 wt%. To prepare a mixed solution.
This mixed solution is applied to the outer peripheral surface of the insulating layer by a dip coating method, dried, and then preheated at 80 ° C. × 0.5 hours, and then heated (baked) at 230 ° C. × 1 hour. went. Thereby, the heat_generation | fever layer which contains the carbon fiber by which the modification process was given in the polyimide resin was obtained. The carbon fiber content in the heat generation layer was 15 wt%.

<4> Next, the roller body on which the heat generating layer is formed is placed in a mold, and in this state, a silicone rubber precursor composition (manufactured by Shin-Etsu Silicone) is supplied into the mold, and 250 ° C. × 4 hours. Heated. After completion of heating, the roller body on which the elastic layer was formed was taken out of the mold.
In addition, the obtained elastic layer was 1.5 mm in average thickness x 300 mm in length.
<5> Next, after covering a heat-shrinkable tube made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer so as to cover the elastic layer, heat treatment was performed, and a surface layer (average thickness 50 μm × length 300 mm) Formed.
As described above, the fixing roller shown in FIG. 6 was obtained.
Then, this fixing roller was incorporated to manufacture the fixing device shown in FIG.

(Example 2)
A fixing roller was manufactured and a fixing device was manufactured in the same manner as in Example 1 except that the carbon fiber content in the heat generating layer was 18 wt%.
(Example 3)
A fixing roller was manufactured and a fixing device was manufactured in the same manner as in Example 1 except that the carbon fiber content in the heat generating layer was 12 wt%.

Example 4
A fixing roller was manufactured and a fixing device was manufactured in the same manner as in Example 1 except that carbon fiber subjected to the following modification treatment was used in Step <3>.
First, the same carbon fiber as in Example 1 was prepared.
Next, this carbon fiber was mixed with a solution prepared by dissolving the ferrocene derivative introduced with a carboxyl group in an AlCl 3 aqueous solution so as to be 1 mmol. As a result, the ferrocene derivative was coordinated to the carbon fiber.
The carbon fiber content in the heat generation layer was 15 wt%.

(Example 5)
In the step <3>, a fixing roller was manufactured and a fixing device was manufactured in the same manner as in Example 1 except that carbon fiber and polymer subjected to the following modification treatment were used.
First, carbon fibers similar to those described above were prepared.
Next, this carbon fiber was mixed with tetramethylcyclotetrasiloxane, and then recovered and dried to undergo cross-linking polymerization. Thereby, the surface of the carbon fiber was coated with polymethylsiloxane.

Next, the modified carbon fiber was mixed with the silicone resin precursor composition to prepare a mixed solution.
This mixed solution was applied to the outer peripheral surface of the insulating layer by a dip coating method, dried, then preheated at 150 ° C. × 40 hours, and then subjected to main heating (firing) at 300 ° C. × 20 hours. . Thereby, the heat_generation | fever layer which contains the carbon fiber by which the modification process was given in the silicone resin (methylphenyl polysiloxane) was obtained. The carbon fiber content in the heat generation layer was 15 wt%.
(Comparative example)
A fixing roller was manufactured and a fixing device was manufactured in the same manner as in Example 1 except that carbon fiber in which the modification treatment was omitted was used in the step <3>.

2. Evaluation In the fixing roller produced in each Example and Comparative Example, the axial resistance value of the heat generating layer and the temperature of the heat generating layer were measured continuously. In addition, for the measurement of the resistance value, a four-end needle method apparatus (manufactured by Mitsubishi Chemical Corporation) was used.
Further, the fixing device manufactured in each of the examples and the comparative example was attached to the image forming apparatus shown in FIG. 1, and the time until printing was possible was measured.
These results are shown in Table 1 below. In Table 1, as an evaluation result, the resistance value in the initial state (indicated as “resistance value” in Table 1), the temperature at which self-temperature control is possible (indicated as “temperature” in Table 1), In addition, the time until printing becomes possible (indicated as “time” in Table 1) is shown.

As shown in Table 1, in the image forming apparatus to which the fixing device manufactured in each example was attached, the time until printing was possible was shortened.
In addition, the fixing roller manufactured in each example had a temperature at which the resistance value suddenly changed, and the temperature was different.
In contrast, in the image forming apparatus to which the fixing device manufactured in the comparative example is attached, it takes a long time until printing is possible.

In addition, the resistance value of the fixing roller manufactured in the comparative example was gradual.
FIG. 8 shows, as an example, a graph showing the relationship between the change in the temperature of the heat generating layer and the change in the resistance value in the fixing roller manufactured in Example 1 and the comparative example.
Further, in the same manner as described above, the fixing roller shown in FIG. 7 was manufactured, the fixing device was manufactured, and the same evaluation was performed. As a result, the same result as described above was obtained. The block-shaped heating element was prepared in the same manner as described above, and after defoaming the mixture under reduced pressure, it was filled in a polytetrafluoroethylene (PTFE) mold and the mixture was cured. Produced.

1 is an overall configuration diagram of an image forming apparatus of the present invention including a fixing device of the present invention. FIG. 3 is a perspective view showing a partially broken section of the fixing device of the present invention. FIG. 3 is a plan view of the fixing device shown in FIG. 2. It is a side view which shows the attachment state of the pressure roller and fixing roller shown in FIG. FIG. 3 is a cross-sectional view of the pressure roller shown in FIG. 2. FIG. 3 is a cross-sectional view of the fixing roller shown in FIG. 2. FIG. 6 is a cross-sectional view of a fixing roller of another configuration example. 6 is a graph showing a relationship between a change in temperature of a heat generation layer and a change in resistance value in fixing rollers manufactured in Example 1 and a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Main body 3 ... Image carrier 4 ... Charging device 5 ... Exposure device 6 ... Rotary developing device 6Y ... Yellow developing device 6M ... Magenta developing device 6C ... Cyan developing device 6K ... Black developing device 6a ... Developing roller 7 ... Intermediate transfer device 8 ... Support frame 9 ... Drive roller 10 ... Driving roller 11 ... Intermediate transfer belt 12 ... Primary transfer roller 13 ... Transfer belt cleaner 14 ... Secondary transfer roller 15 ... Paper feed cassette 16 ... Pickup roller 17 ... Recording medium transport path 19 ... Fixing device 20 ... Paper discharge tray 21 ... Fixing roller 210 ... Roller Body 211 …… Cylinder 212 …… Insulating layer 213 …… Heat generation layer 214 …… Elastic layer 215 …… Surface layer 216 …… Rotation shaft 217 …… But Lashi electrode 218 ...... Heat generation block 22 ...... Pressure roller 221 ...... Cylindrical body 222 ...... Rotating shaft 223 ...... Elastic layer 224 ...... Surface layer 23 ...... Transport path for double-sided printing 24 …… Housing 25 …… Bearing 26 ... ... Pressure lever 27 ... Pressure spring 28 ... Drive gear 29, 30 ... Support shaft 31,32 ... Peeling member 40 ... Place N ... Nip part

Claims (9)

A fixing roller used in a fixing process for fixing an unfixed image carried on a recording medium to the recording medium,
The roller body,
An elastic layer provided on the outer peripheral surface side of the roller body;
A heating element that has a self-temperature control function, generates heat when energized, and heats the fixing roller;
The fixing roller, wherein the heating element comprises a carbon-based material subjected to a modification treatment for improving adhesion to the polymer in the polymer.   The fixing roller according to claim 1, wherein the modification treatment is a treatment in which a compound having a reactive group capable of reacting with the polymer is covalently bonded or coordinated to the carbon-based material.   The modification treatment is performed by reacting a precursor of a second polymer having high compatibility with the polymer on the surface of the carbon-based material, and coating the surface of the carbon-based material with the obtained second polymer. The fixing roller according to claim 1, wherein the fixing roller is a process that performs the above processing.   4. The fixing roller according to claim 1, wherein a content of the carbonaceous material in the heating element is 1 to 30 wt%.   The fixing roller according to claim 1, wherein the heating element is provided in a layered manner on an outer peripheral surface of the roller body. The heating element is provided in contact with the elastic layer,
The fixing roller according to claim 5, wherein the polymer is highly compatible with a constituent material of the elastic layer. The roller body has a cylindrical shape,
The fixing roller according to claim 1, wherein the heating element is provided so as to contact an inner peripheral surface of the roller body. A fixing roller; and a pressure roller pressed against the fixing roller, and passing a recording medium carrying an unfixed image between the fixing roller and the pressure roller, thereby allowing the recording medium to pass through the recording medium. A fixing device for fixing an unfixed image,
A fixing device, wherein at least one of the fixing roller and the pressure roller is constituted by the fixing roller according to claim 1.   An image forming apparatus comprising the fixing device according to claim 8.

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