JP2002311633A - Electrophotographic fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic fixing method by which a high- quality color image having sufficient color mixture and transparency is formed. SOLUTION: In this electrophotographic fixing method, the image is fixed on a recording medium by using a toner image fixing device where non-magnetic toner which consists of at least a colorant and binding resin and whose storage elastic modulus on the condition of 110 deg.C is <=3×10<4> Pa. whose loss elastic modulus on such a condition is <=6×10<4> Pa, whose storage elastic modulus on the condition of 150 deg.C is >=1×10 Pa, and whose loss elastic modulus on such a condition is >=1×10<2> Pa is included, and an endless fixing belt having a mold-released layer on the surface of a belt main body is stretched and a pressure roller pressing the fixing roller from below through the fixing belt is positioned to constitute a nip part between the fixing belt and the pressure roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic fixing method, and more particularly, to a full-color electrophotographic method used in an image forming apparatus using a so-called electrophotographic method, such as an electrostatic copying machine or a laser beam printer. The present invention relates to a fixing method and an electrophotographic toner.

[0002]

2. Description of the Related Art Conventionally, many methods have been known as electrophotography. In general, a photoconductive material is used, and an electrophotographic method is used to form an electric image on a photoreceptor by various means. A latent image is formed, and then the latent image is developed using toner. If necessary, the toner image is transferred to a recording medium such as paper, and then the toner image is fixed by heating, pressure, or solvent vapor to copy. Get things.

A full-color image in electrophotography is formed by superimposing toners of three colors of yellow (Y), magenta (M), and cyan (C) or four colors including black. That is, the charging, exposing, developing, and transferring processes are repeated for each of these toners to form a toner image composed of a plurality of color toners on a recording medium, and the toner image is melted and mixed (mixed colors) to form a recording medium. A full-color image is formed by fixing it on the top. Various methods and apparatuses have been developed for the step of fixing a toner image on a recording medium such as paper, which is the final step of such full-color image formation. At present, the most common fixing method is a pressure heating method using a heating roller.

In this press-fit heating method, the recording medium is brought into contact with and passed through a heating roller, the surface of which is formed of a material having releasability from toner, under pressure on the toner image surface of the recording medium. And fixing a toner image on a recording medium. In this method, since the surface of the heating roller and the toner image on the recording medium come into contact under pressure,
The thermal efficiency at the time of fusing the toner image onto the recording medium is extremely good, and the fixing can be performed quickly, which is very effective. However, in the above method, since the surface of the heating roller and the toner image come into contact under pressure in a molten state,
A part of the toner image adheres and transfers to the roller surface, and re-transfers to the next recording medium, causing a so-called offset phenomenon, which may stain the recording medium. Therefore, preventing the toner from adhering to the roller surface is one of the technical problems of the pressure bonding heating method using the heating roller.

In addition, when a full-color toner is used, the toner fixed on the recording medium is almost completely melted so that the shape of the toner particles cannot be determined so that the toner does not irregularly reflect light and hinder color reproduction. It is necessary to make it close. If the melting and mixing of the toner is insufficient, the transparency of the toner image decreases, the color mixing property is impaired, the color reproducibility of the color image is deteriorated, and the surface of the toner image after fixing becomes uneven. This is because the generated irregularities irregularly reflect the incident light, so that the quality of the resulting color image is degraded due to loss of vividness.

However, the time required for the toner image to contact the heating roller, that is, the effective fixing time, is extremely short, usually about 1 × 10 ^-2 to 5 × 10 ^-2 seconds. Properties are required for electrophotographic color toners. Therefore, the full-color toner has a smaller cohesive force at the time of melting than the conventional mono black toner, and remarkably generates an offset. Therefore, it is a common practice to apply a large amount of a release agent such as silicone oil to the surface of the heating roller for a color toner having a characteristic that the viscosity rapidly decreases during fixing.

On the other hand, applying a large amount of silicone oil not only causes a large and complicated fixing device, but also causes problems such as generation of oil streaks in an image and deterioration of the transparency of an OHP sheet image. Under such circumstances, as a fixing method for full-color toner, there is no offset, a wide fixing temperature range, the toner image has transparency, and the fixing surface becomes flat when fixed, and the image deterioration due to silicone oil is caused. There is a demand for a method that does not occur. Also,
Japanese Patent Application Laid-Open No. Hei 6-318001 discloses that the temperature of a nip portion is set low by preheating toner and a recording medium via a fixing belt, and that a fixing belt is used when passing through the nip portion by using a belt having a small heat capacity. A method has been proposed in which the belt is rapidly cooled to lower the temperature of the toner on the recording medium separated from the fixing belt at the exit of the nip portion, thereby obtaining an image without offset by applying oilless or trace oil.

However, even in this method, depending on the characteristics of the toner used, it cannot be said that sufficient color mixing properties and a sufficient fixing temperature range can be attained in oilless or trace oil application. Further, in conventional toners, a method using an anti-offset agent has been proposed for the purpose of expanding the fixing temperature range. However, the addition of such an anti-offset agent lowers the fluidity of the toner itself or causes a two-component toner. In the case of the system toner, there are various problems that the spent of the carrier is promoted and charging failure occurs, and the transparency of the toner is lost for a full-color toner. Further, a method has been proposed in which a polyvalent carboxylic acid is used as a resin component in a toner and a three-dimensional structure is provided in a polyester to thereby improve the offset resistance.

However, these methods can improve the anti-offset property, but the toner contains a large amount of a crosslinking component or a high-molecular component, so that the elasticity of the toner is increased. The fixing surface does not become flat, and there is a problem in terms of color reproduction for a full-color toner. Further, JP-A-4-12367 and JP-A-5-165252 propose toners using cyclohexanedimethanol as an essential component as a polyhydric alcohol component and a polyester resin as a binder resin. Therefore, even when a toner image is fixed by a fixing method generally used using such a toner, sufficient color mixing cannot be performed, and the surface of the toner image is not considered. Is smooth,
At present, high-quality color images with a wide color reproduction and fixing temperature range and with suppressed image deterioration due to oil have not been obtained.

The present invention has been made in view of the above problems, has sufficient color mixing and transparency, has a flat surface of the obtained toner image, has a wide color reproduction, and has no image deterioration due to oil. It is another object of the present invention to provide an electrophotographic fixing method that can form a high-quality color image with a wide fixing temperature range.

[0011]

According to the first aspect of the present invention, a storage elastic modulus at 110 ° C. is 3 × 10 ⁴ Pa or less, and a loss elastic modulus is 6 × 10 ⁴ , comprising at least a colorant and a binder resin. A non-magnetic toner having a storage elastic modulus at 150 ° C. of 1 × 10 Pa or more and a loss elastic modulus of 1 × 10 ² Pa or more at 150 ° C. or less, and a release layer on the belt-main surface between the fixing roller and the heating roller. An endless fixing belt having an endless fixing belt, a pressure roller for pressing the fixing roller from below through the fixing belt is provided, and a nip portion is formed between the fixing belt and the pressure roller. And an electrophotographic fixing method comprising fixing the recording medium to a recording medium using the same.

According to a second aspect of the present invention, there is provided a non-magnetic toner comprising at least a colorant and a binder resin, wherein the binder resin is a polyester resin having cyclohexanedimethanol as an essential component as a polyhydric alcohol component. An endless fixing belt having a release layer on the surface of the belt main body is stretched between the fixing roller and the heating roller, and a pressure roller that presses the fixing roller from below through the fixing belt is provided. An electrophotographic fixing method including fixing a recording medium using a toner image fixing device having a nip between a fixing belt and a pressure roller is provided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fixing method according to the present invention
Using a non-magnetic toner and a specific toner image fixing device
And fixing the toner on the recording medium. First
In the present invention, the dynamic viscoelastic properties of the toner
Storage elastic modulus of 3 × 10^FourPa or less, loss elastic modulus is 6 × 1
0^FourPa or less, the storage elastic modulus at 150 ° C. is 1 × 10 Pa or more,
Loss modulus is 1 × 10^TwoIt is preferably at least Pa. 1
Storage elasticity at 10 ℃ is 3 × 10^FourIf it is Pa or more,
-Particles can be completely melted, resulting in a vivid image without irregularities
The low temperature side of the temperature range becomes narrow, and the loss elastic modulus is 6 × 1
0 ^FourIf it is Pa or more, the low-temperature side where it is fused on the sheet to be fixed
This is because the non-offset temperature region becomes narrower. 150 ℃
Storage elastic modulus is 1 × 10 Pa or less, loss elastic modulus is 1 × 1
0^TwoBelow Pa, the non-offset region on the high temperature side becomes narrow.
This is because that. Here, the storage elastic modulus of the toner is
The component and the loss modulus are based on the viscosity component.
The storage elastic modulus and loss elastic modulus of the non-magnetic toner of the present invention
The method of adjusting the value within the above range is particularly limited.
For example, adjust the molecular weight distribution of the binder resin of the toner.
Or methods of blending resins.
You.

As the colorant in the non-magnetic toner of the first and second inventions, various colorants according to desired colors such as yellow (Y), magenta (M), cyan (C) and black are exemplified. Can be As the colorant for the yellow (Y) toner, for example, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 5, C.I.
I. Pigment Yellow 12, C.I. I. Pigment Yellow 15, C.I. I. Azo pigments such as CI Pigment Yellow 17; and inorganic pigments such as yellow iron oxide and loess. Examples of the dye include C.I. I. Nitro dyes such as Acid Yellow 1; I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I.
I. Solvent Yellow 14, C.I. I. Solvent Yellow 15, C.I. I. Solvent Yellow 19, C.I.
I. And oil-soluble dyes such as Solvent Yellow 21. Among them, C.I. I. Benzidine pigments such as CI Pigment Yellow 17 are preferred in terms of tint as a yellow colorant.

As a colorant for magenta (M) toner, for example, C.I. I. Pigment Red 49, C.I. I.
Pigment Red 57, C.I. I. Pigment Red 8
1, C.I. I. Pigment Red 122, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I.
I. Solvent Red 52, C.I. I. Basic Red 10, C.I. I. Disperse Red 15 and the like. Among them, C.I. I. A quinacridone-based pigment such as Pigment Red 122 is preferred in terms of the color as a magenta-based colorant.

As a colorant for cyan (C) toner,
For example, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 16, C.I. I. Solvent blue 55,
C. I. Solvent Blue 70, C.I. I. Direct Blue 25, C.I. I. Direct Blue 86 and the like. Among them, C.I. I. Pigment Blue 15 and other copper phthalocyanine pigments are preferred in terms of color as a cyan-based colorant. As the black, carbon black is preferably used.

In particular, as the binder resin of the non-magnetic toner in the first invention, for example, polystyrene, poly-
p-chlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-
Vinyl chloride copolymer, styrene-vinyl acetate copolymer,
Styrene-maleic acid copolymer, styrene-acrylate copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc., styrene-methacrylate copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate) Copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer,
Styrene-phenyl methacrylate copolymer), styrene-α-methyl methacrylate copolymer, styrene-
Styrene resins such as acrylonitrile-acrylate copolymers (homopolymers or copolymers containing styrene or styrene substituents), polyvinyl chloride, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-ethyl acrylate copolymer Coalescing, polyvinyl butyral, ethylene-vinyl acetate copolymer, rosin-modified maleic resin,
Phenolic resin, epoxy resin, polyester resin, ionomer resin, polyurethane resin, silicone resin,
Ketone resins, xylene resins, polyamide resins and the like are listed. These may be used alone or in combination of two or more. In a full-color toner, a polyester resin is preferable from the viewpoint of controlling thermal characteristics and the like.

As the binder resin in the non-magnetic toner of the second invention, a polyester resin containing cyclohexane dimethanol as an essential component as a polyhydric alcohol component is particularly exemplified. Among them, as the polyhydric alcohol component, a polyester resin containing a bisphenol A alkylene oxide adduct (for example, ethylene oxide 2 mol adduct, propylene oxide 2 mol adduct) as an essential component is exemplified. In addition to these alcohol components, ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3- Divalent alcohols such as butanediol, 1,4-butenediole, 1,5-pentanediole, 1,6-hexanediol, hydrogenated bisphenol A, glycerin, trimethylolethane, and trimethylo Tri- or higher-valent alcohols such as -propane, trishydroxyethyl isocyanurate and pentaerythritol may be used.

The polybasic acid components constituting the polyester resin include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecenylsuccinic acid, n-dodecylsuccinic acid,
Malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, cyclohexanedicarboxylic acid,
Orthophthalic acid, isophthalic acid, dibasic acids such as terephthalic acid, trimellitic acid, trimetic acid, three or more base acids such as pyromellitic acid and anhydrides thereof, lower alkyl esters, and the like, Terephthalic acid or a lower alkyl ester thereof is preferred, and the binder resin of the toner of the present invention is, in addition to the polyester resin, another resin such as a styrene acrylic resin, an epoxy resin, a polyester resin, a petroleum resin, or the above-described binder resin. It may be used by blending with a resin or the like.

The non-magnetic toner of the first and second inventions may contain a charge controlling agent for the purpose of controlling the triboelectric charging property of the toner. It is preferable to use the charge control agent separately for positive charge control and negative charge control according to the charging characteristics of the toner. Examples of the charge control agent for controlling the positive charge include organic compounds having a basic nitrogen atom, such as basic dyes, quaternary ammonium salts, aminopyrine, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, and nigrosine base. . Examples of the charge control agent for negative charge control include oil-soluble dyes such as oil black and spiron black, metal-containing azo dyes, metal salts of naphthenic acids, metal salts of alkyl salicylic acids,
Fatty acid soap, resin acid soap and the like can be mentioned. The charge control agent is preferably contained in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the binder resin. In a color toner, a colorless quaternary ammonium salt, a metal salt of alkyl salicylic acid, or the like is desirable.

Further, the non-magnetic toner of the present invention may contain a surface treating agent for the purpose of adjusting the fluidity, chargeability and the like of the toner. Examples of the surface treatment agent include vinylidene fluoride fine powder, polytetrafluoroethylene fine powder, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, aluminum oxide powder, titanium oxide powder, fine powder silica, and the like. Can be The surface treatment agent is added in an amount of 0.1 to 100 parts by weight of the colorant-containing resin.
It is preferably contained in an amount of 0.1 to 10 parts by weight,
More preferably, it is 5 parts by weight. Although the particle size of the non-magnetic toner is not particularly limited, for example, a toner having an average particle size of about 3 to 30 μm is preferable. In particular, in order to obtain a high-quality image, the particle size is preferably a small particle size of about 9 μm or less, more preferably 4 to 9 μm,
5-8 μm is more preferred.

The non-magnetic toner of the present invention comprises a dry blender together with a colorant, a binder resin, and optionally other additives.
Super-mixer, pre-mix homogeneously with a boldle, etc., and further, the mixture is uniformly melt-kneaded using a kneading apparatus such as a Banbury mixer, a roll, a single-screw or twin-screw extrusion kneader, and then cooled and pulverized. And, if necessary, by classifying.

The toner image fixing device used in the present invention mainly comprises, for example, a fixing roller, a heating roller, a pressure roller and a fixing belt as shown in FIG. An endless fixing belt is stretched between the fixing roller and the heating roller. The surface of the fixing roller preferably has a heat-resistant elastic coating layer made of, for example, silicone rubber. The heating roller preferably includes a heat source therein and is made of a heat-resistant material whose temperature can be controlled by a thermistor.

The fixing belt is composed of a belt base and a release layer formed on the outer surface of the fixing belt. It is preferable that the nickel electroformed belt is coated with silicone rubber.
In particular, it is not limited. A fluorine resin may be used for the polyimide belt main body and the coating release layer. The pressure roller is arranged to press the fixing roller from below the fixing roller via the fixing belt. It is preferable that the surface of the pressure roller has a heat-resistant elastic coating layer made of, for example, silicone rubber, and is harder than the fixing roller. In this manner, a concave fixing nip portion is formed between the fixing belt and the pressure roller by the pressing of the pressure roller. The fixing nip portion preferably has a concave shape on the fixing belt side. Note that the pressure roller may include an auxiliary heating source for the purpose of improving the fixing performance.

In the toner image fixing device of the first invention, it is preferable that the silicone oil application roller is provided in such a manner that the silicone oil can be applied to the fixing roller at 0.5 to 10 mg / A4. In the second invention, a mechanism for applying a small amount of silicone oil to the fixing belt may be used, but the invention is not particularly limited thereto. The fixing device can supply a stable amount of heat from the heating roller to the fixing nip by using a belt having a small heat capacity, and can stabilize the temperature of the toner in the fixing nip. In addition, by rapidly cooling the fixing belt, the temperature of the toner on the recording medium that is separated from the fixing belt at the exit of the fixing nip can be suppressed. You can get up to.

By using such a fixing device and the toner according to the first aspect of the invention, the loss elasticity, which is deeply related to the binding property between the toner and paper and the melting property of the toner particles, and the releasability from the fixing device are improved. By controlling the relationship of the storage elastic modulus, which is closely related to a certain toner cohesive force and the surface state of the toner layer, it is possible to control better color development and non-offset width. Further, by using the fixing device described above and the toner according to the second aspect of the invention, fine crystalline portions are dispersed throughout the resin, and a portion having high elasticity can be generated in the toner. The toner does not impair the state, the offset of the toner is improved due to the partial increase in cohesion, and the fused state of the toner can be improved due to a synergistic effect compared to using the toner and the fixing device alone, and color formation It is possible to obtain a high-quality color image with high resilience, a wide non-offset width, and no image deterioration due to oil.

[0027]

EXAMPLES Hereinafter, examples of the electrophotographic fixing method and the electrophotographic toner of the first invention will be described in detail. Examples 1 to 4 and Comparative Examples 1 to 8 Toner Image Fixing Apparatus FIG. 1 shows a toner image fixing apparatus A used in this embodiment. In FIG. 1, the fixing roller R1 has a 15 mm diameter iron core covered with a 10 mm thick silicone sponge, and has an outer diameter of 35 mm. Heating roller R3
Is a hollow cylindrical core metal made of aluminum having a diameter of 30 mm, which is anodized. A fixing belt B having an outer diameter of 60 mm is stretched between the fixing roller R1 and the heating roller R3. The fixing belt B is an endless belt having an outer shape of 60 mm in which a nickel electroformed belt base having a thickness of 40 μm is covered with a release layer made of silicone rubber having a thickness of 0.15 mm.

The pressure roller R2 is made of an iron core having a diameter of 28 mm coated with a silicone rubber having a thickness of 2 mm, and has an outer diameter of 30 mm. By pressing the fixing roller R1 from below via the fixing belt B, a 6 mm concave nip portion N is formed between the fixing belt B and the pressure roller R2 on the fixing belt B side. The pressure at the nip N is set to 40 kg. A main heating source H1 is provided inside the heating roller R3,
The temperature is adjusted by the thermistor S. An auxiliary heating source H2 is provided inside the pressure roller R2. The silicone oil application roller I has an outer diameter of 20 mm,
It is controlled so that silicone oil is applied at 2 to 8 mg / A4.

Preparation of Toner for Toner / Yellow 100 parts by weight of a binder resin (polyester) and a colorant (C.I.
I. Pigment Yellow 17) and 2.0 parts by weight of a charge control agent (zinc compound of salicylic acid) were uniformly mixed by a super mixer, and then heated and melted and kneaded by a twin-screw extruder, followed by cooling. The weight average molecular weight and number of the binder resin (a polyester resin composed of a 1.2 mol adduct of bisphenol A propylene oxide and terephthalic acid, fumaric acid or trimellitic anhydride) used in each of the following Examples and Comparative Examples. Table 1 shows the average molecular weight.

[0030]

[Table 1]

The obtained kneaded product was coarsely pulverized by a cutting mill, then finely pulverized by an ultrasonic jet mill, and fine powder of 5 μm or less was removed by a classifier to obtain a yellow (Y) color toner. The particle size of the toner was distributed in the range of 5 to 16 μm, and the average particle size was 8.0 μm.

Preparation of toner for cyanide C.I. I. Pigment Blue 15 was used in the same manner as described above to prepare a color toner for cyan (C) used in each of Examples and Comparative Examples.

Dynamic viscoelasticity of toner Dynamically changing stress is applied to the toners for yellow and cyan obtained above, and the storage elastic modulus and the loss elastic modulus at this time are determined.
The measurement was performed using a RheoStress RS75 manufactured by HAAKE. The dynamic change stress was applied with a 20 mm parallel plate with a gap of 0.085 mm and a strain of 50% at 1.0 Hz. Temperature conditions, set the sample at 140 ℃,
After cooling to 90 ° C., the measurement was carried out from 90 ° C. to 200 ° C. at a temperature increase rate of 3 ° C./min. Table 2 shows the results.

[0034]

[Table 2]

Printing Test I The obtained color toners for yellow (Y) and cyan (C) were mixed with a carrier to prepare developers for the respective colors. Ferrite particles were used as the carrier, and the toner concentration of the developer was set to 4.0%. Next, a color electrophotographic apparatus equipped with an OPC photosensitive drum and using the toner image fixing device A described above at a speed of 120 m
m, the set temperature of the fixing roller was changed from 100 to 220 ° C. by 10 ° C. in increments of 10 ° C., and a color image composed of yellow (Y) and cyan (C) toners was formed on a recording medium (paper).

A color electrophotographic apparatus provided with an OPC photosensitive drum, comprising a fixing roller 1, a heater lamp 2, a pressure roller 3, a concave portion 4 in a rubber layer, and an oil application roller 5, as shown in FIG. A color image was formed by using a typical heat-fixing roller fixing device D and setting the nip width, speed, and set temperature of the fixing roller in the same manner.
The obtained color image is irradiated with light of 540 nm to measure the spectral reflection characteristics, and the reduction ratio (%) is obtained by comparing with the reflectance of the cyan (C) developer single color image, and the reduction ratio is obtained. Is less than 5%. This is because when the reduction rate is 5% or more, the color mixing becomes insufficient and the color development is not preferable. Table 3 shows the results.

Printing Test II Using a cyan (C) color toner in the same manner as above,
An image of one to three layers was created by up to three transfers, and a non-offset temperature range was determined. Table 3 shows the results.

[0038]

[Table 3]

As is clear from Table 3, in Examples 1 to 4, good results were obtained in both the color mixture area (color developing property) and the non-offset area. Good results were not obtained because the dynamic viscoelastic properties were outside the scope of the invention. Comparative Example 6
In Nos. 9 to 9, since the fixing device used was not one according to the present invention, good results could not be obtained even if the dynamic viscoelastic properties of the toner were within the range of the present invention. Hereinafter, examples of the electrophotographic fixing method of the second invention will be described in detail.

Examples 5 to 7 and Comparative Examples 9 to 17 Toner Image Fixing Apparatus FIG. 3 shows a toner image fixing apparatus B used in this embodiment. In FIG. 3, the fixing roller R1 has a 15 mm diameter iron core covered with a 10 mm thick silicone sponge, and has an outer diameter of 35 mm. Heating roll R3
Is a hollow cylindrical core metal made of aluminum having a diameter of 30 mm, which is anodized. A fixing belt B having an outer diameter of 60 mm is stretched between the fixing roller R1 and the heating roller R3. The fixing belt B is an endless belt having an outer shape of 60 mm in which a nickel electroformed belt base having a thickness of 40 μm is covered with a release layer made of silicone rubber having a thickness of 0.15 mm.

The pressure roll R2 has a 28 mm diameter iron core coated with a 2 mm thick silicone rubber, and has an outer diameter of 30 mm. By pressing the fixing roller R1 from below via the fixing belt B, a 6 mm concave nip portion N is formed between the fixing belt B and the pressure roller R2 on the fixing belt B side. . The pressure at the nip N is set to 40 kg. A main heating source H1 is provided inside the heating roller R3, and the temperature is adjusted by a thermistor S. An auxiliary heating source H2 is provided inside the pressure roller R2.

Preparation of Toner / Yellow Toner A polyester resin consisting of 1,4-cyclohexanedimethanol, 2.2 mol of bisphenol A ethylene oxide adduct, terephthalic acid or trimellitic anhydride was used as the binder resin. In the same manner as in Examples 1 to 4, a yellow (Y) color toner was obtained. The particle size of the toner was distributed in the range of 5 to 16 μm, and the average particle size was 8.0 μm. Table 4 shows the weight average molecular weight and the number average molecular weight of the binder resin used here.

[0043]

[Table 4]

Further, the binder resin (bisphenol A propylene oxide 1.2 mol adduct,
Table 5 shows the weight average molecular weight and the number average molecular weight of the polyester resin comprising terephthalic acid, fumaric acid or trimellitic anhydride).

[0045]

[Table 5]

The cyan (C) color toner is also used as a colorant. I. It was prepared in the same manner as described above except that Pigment Blue 15 was used.

Printing Test I In the same manner as in Examples 1-4, a developer comprising the yellow (Y) and cyan (C) color toners obtained above and a carrier was prepared. Next, a color electrophotographic apparatus having an OPC photosensitive drum, and using the above-described toner image fixing device B, the speed is changed to 120 mm, the set temperature of the fixing roller is changed from 100 to 210 ° C. in steps of 10 ° C., A color image composed of yellow (Y) and cyan (C) toners was formed on a recording medium (paper). Also, in a color electrophotographic apparatus having an OPC photosensitive drum,
As shown in FIG. 4, a general heat-fixing roller fixing device having a fixing roller 1, a heater lamp 2, a pressure roller 3, and a concave portion 4 in a rubber layer is used, and the width, speed, and setting of the fixing roller are set. At the same temperature, a color image was formed. The obtained color image is irradiated with light of 540 nm to measure the spectral reflection characteristics, and the reduction ratio (%) is obtained by comparing with the reflectance of the cyan (C) developer single color image, and the reduction ratio is obtained. Is less than 5%. Table 6 shows the results.

Printing Test II Using a cyan (C) color toner,
An image of one to three layers was created by up to three transfers, and a non-offset temperature range was determined. Table 6 shows the results.

[0049]

[Table 6]

As is clear from Table 6, in Examples 5 to 7, good results were obtained in both the color mixing range (color developing property) and the non-offset range, but in Comparative Examples 9 to 11, the results of the present invention were obtained. Since a toner having no resin composition was used, good results could not be obtained. In Comparative Examples 12 to 14, good results could not be obtained even if the resin composition of the present invention was used because the fixing device used was not of the present invention. Further, from Comparative Examples 15 to 17 and 12 to 14,
It has been found that even when the resin composition is within the range of the present invention, there is a large difference in performance when the fixing device is not of the present invention.

[0051]

According to the present invention, by fixing a toner to a recording medium by using a specific non-magnetic toner and a specific fixing device, the melting state of the toner is improved, the color development is high, and the non-offset is improved. A wide image can be obtained. That is, by using the fixing device of the present invention and the toner of the first invention, the loss elasticity and the releasability from the fixing device are deeply related to the binding property between the toner and the paper and the melting property of the toner particles. By controlling the relationship of the storage elastic modulus, which is deeply related to the toner cohesive force and the surface state of the toner layer, it is possible to control better color development and non-offset width.

In particular, the present invention is effective for color image toners that require almost complete melting of toner particles. Further, when the fixing nip portion on the fixing belt side of the fixing device has a concave shape, the offset width can be made wider due to the relationship of the peeling angle. Further, when the binder resin of the toner is a polyester resin, control of thermal characteristics becomes easy,
It is advantageous. In addition, when the fixing device has a mechanism for applying a trace amount of the anti-offset agent to the fixing belt at 0.5 to 10 mg / A4, a high-quality full-color image without image deterioration due to oil can be obtained.

Further, by using the fixing device of the present invention and the toner of the second invention, fine crystalline portions are dispersed throughout the resin, and a portion having high elasticity can be generated in the toner. . Moreover, the toner melt state is not impaired, and the offset property is also improved due to the partial increase in cohesive force of the toner, so that the toner melt state is more improved by a synergistic effect than when the toner and the fixing device are used alone. be able to. Therefore, it is possible to obtain a high-quality color image having high color developability, a wide non-offset width, and no image deterioration due to oil. In particular, when a polyester resin containing cyclohexane dimethanol and a bisphenol A alkylene oxide adduct as essential components as a polyhydric alcohol component is used, the heat resistance and cohesiveness of the toner can be improved, and higher quality can be achieved. A full-color image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part for describing a configuration of an electrophotographic fixing device according to the present invention.

FIG. 2 is a schematic cross-sectional view of a main part for describing a configuration of a general fixing device.

FIG. 3 is a schematic cross-sectional view of a main part for describing a configuration of another electrophotographic fixing device according to the present invention.

FIG. 4 is a schematic cross-sectional view of a main part for describing a configuration of another general fixing device.

[Explanation of symbols]

 R1, 1 fixing roller R2, 3 pressing roller R3 heating roller B fixing belt N nip portion H1 main heating source H2 auxiliary heating source S thermistor I silicon oil application roller 2 heater lamp 4 concave portion 5 oil application roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/20 102 G03G 9/08 331 (72) Inventor Tetsu Ogawa 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka No. Sharp Corporation F-term (reference) 2H005 AA01 AA21 CA08 EA10 FA01 2H030 AD01 AD04 2H033 AA11 BA11 BA12 BA25 BA58 BB18 BB30

Claims (9)

[Claims] 1. A composition comprising at least a colorant and a binder resin, having a storage elastic modulus at 110 ° C. of 3 × 10 ⁴ Pa or less, a loss elastic modulus of 6 × 10 ⁴ Pa or less, and a storage elastic modulus at 150 ° C. 1 × 10
Pa or more, a non-magnetic toner having a loss elastic modulus of 1 × 10 ² Pa or more, and an endless fixing belt having a release layer on the surface of the belt main body between the fixing roller and the heating roller is stretched,
Using a toner image fixing device provided with a pressure roller for pressing the fixing roller from below through the fixing belt and forming a nip portion between the fixing belt and the pressure roller,
An electrophotographic fixing method comprising fixing to a recording medium. 2. The method according to claim 1, wherein the non-magnetic toner is a color toner comprising at least a yellow (Y) toner, a magenta (M) toner, and a cyan (C) toner. 3. The method according to claim 1, wherein the fixing nip portion of the toner image fixing device has a concave shape on the fixing belt side. 4. The method according to claim 1, wherein the binder resin of the non-magnetic toner is a polyester resin. 5. The method according to claim 1, wherein the fixing belt of the toner image fixing device is provided with a mechanism for applying 0.5 to 10 mg / A4 of a trace offset preventing agent. 6. A non-magnetic toner comprising at least a colorant and a binder resin, wherein the binder resin is a polyester resin having cyclohexane dimethanol as an essential component as a polyhydric alcohol component, and a fixing roller and a heating roller. An endless fixing belt having a release layer is stretched on the surface of the belt main body, and a pressure roller that presses the fixing roller from below through the fixing belt is provided, between the fixing belt and the pressure roller. An electrophotographic fixing method comprising fixing a recording medium using a toner image fixing device having a nip portion. 7. The method according to claim 6, wherein the non-magnetic toner is a color toner comprising at least a yellow (Y) toner, a magenta (M) toner, and a cyan (C) toner. 8. The method according to claim 6, wherein the binder resin of the non-magnetic toner is a polyester resin containing cyclohexane dimethanol and a bisphenol A alkylene oxide adduct as essential components as a polyhydric alcohol component. 9. The fixing nip portion of the toner image fixing device has a concave shape on the fixing belt side.
The method according to any one of the preceding claims.