JP2769857B2 - Fixing method of full color toner image - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly, to a method for fixing a full-color toner image in which the durability of a fixing roller has been significantly improved.

[Prior Art] Conventionally, many electrophotographic methods are known as described in U.S. Pat. No. 2,976,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748. In general, using a photoconductive substance, an electric latent image is formed on a photoreceptor by various means, and then the latent image is developed using a toner. After the image is transferred, the image is fixed by heating or pressure to obtain a copy.

Also, various development methods for visualizing an electric latent image using toner have been known.

For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. No. 2,815,552, and the jumping-brush development method and liquid development method described in JP-A-62-63970. Many other developing methods are known. Conventionally, fine powders in which a dye or a pigment is dispersed in a natural or synthetic resin have been used as a toner used in such a developing method. Further, it is known to use a finely developed powder to which a third substance is added for various purposes.

In recent years, the development from white-black copiers to full-color copiers is rapidly progressing, and two-color copiers and digitized full-color copiers are on the market.

Color image formation by full-color electrophotography generally reproduces all colors using three color toners of three primary colors, yellow, magenta, and cyan, or four colors including black.

The general method is to first form an electrostatic latent image on a photoconductive layer by passing light from a document through a color separation light transmitting filter having a complementary color relationship with the color of the toner. Next, the toner is held on a support through development and transfer steps. Next, the above-described steps are sequentially performed a plurality of times, and while the registration is being performed, the toner is superimposed on the same support, and the final full-color image is obtained by performing the fixing only once.

In such a color electrophotography method in which development is performed a plurality of times and several types of toner layers having different colors are superposed on the same support as a fixing step, the fixing characteristics that the color toner should have are extremely important. Element.

That is, the fixed color toner is required to suppress irregular reflection due to toner particles as much as possible and have appropriate gloss and gloss.

Further, the color toner must be transparent and have a wide color reproducibility so as not to hinder the toner layers of different color tones under the toner layer.

As color toners that can satisfy these requirements, the present applicants have disclosed Japanese Patent Application Laid-Open Nos. Sho 50-62442 and Sho 51-144625,
JP-A-59-57256 discloses a novel combination of a color binder resin and a colorant.

The color toners described above have considerable sharp melt properties, change the toner shape to a state close to complete melting at the time of fixing, and obtain favorable glossiness and color reproducibility. However, the offset resistance is not yet sufficient.

The fixing roller is roughly classified into a silicone rubber roller and a Teflon-coated roller.Especially, when a silicone rubber roller is used as the fixing roller, the silicon rubber surface is essentially separated by repeated use regardless of the application of a releasing oil. Due to the reduction in moldability, high-temperature offset is likely to occur. In the silicon rubber roller, a certain degree of mold releasability can be maintained at the beginning of use due to the smoothness and cleanliness of the roller surface. However, when a color copy having a large image area and a large toner holding amount on a support as compared with a black-and-white copy image continues to be copied, the releasability of the roller gradually decreases. The speed at which the releasability deteriorates reaches several times that of black-and-white copying. As a result, a so-called high-temperature offset occurs in which a toner film or a granular attachment is formed on the roller surface after only several thousand to tens of thousands of sheets, or the toner upper layer portion of the image surface is peeled off when passing through the heat roller. .

On the other hand, a Teflon-coated roller generally has good durability, but easily spreads the toner by pressure, and therefore has a disadvantage that the resolution is reduced in a copy image and the background stain is conspicuous. In order to improve these drawbacks, a rubber coated with a PFA (perfluoroalkoxy resin) tube of 100 to 300 μm (Japanese Patent Publication No. 58-4374)
No. 0 publication). When these rollers are used, the reduction in the resolving power of the copied image due to the toner expansion is improved.

However, in general, when a Teflon-coated roller is used as a fixing roller, for example, a roller in which an outer peripheral surface of a cored bar is covered with a relatively thick rubber or other elastic material layer is used as a pressure roller.

In this case, contrary to the direction shown in FIG. 1, the direction in which the sheet is discharged from the fixing roller after fixing is performed in a direction perpendicular to the line connecting the centers of the fixing roller and the pressure roller is toward the fixing roller. I have.

For this reason, the fixed image is dragged by the fixing roller even after passing through the nip portion where the fixing roller and the pressure roller are in contact with each other, causing a so-called “swirling” phenomenon, thereby causing an offset. In order to prevent this, there is a method to attach a separation sheet for paper ejection.However, this separation sheet is in contact with the fixing roller, and therefore may cause scratches or leave streaks on the image surface. In a full-color copy of a photograph having a large area, the image quality is significantly reduced.

Various measures have been attempted for fixing devices and toners to solve or alleviate this problem, but they have not been sufficiently solved.

As the fixing device, a material having excellent surface releasability is used.
Alternatively, a device such as applying oil to the roller is used.
Most of the heat roller fixing devices of currently commercialized copiers apply oil in some form. However, the application of a large amount of oil to enhance the releasability causes undesired problems such as oil contamination of the sheet and an increase in cost.

In addition, as a toner, a method of adding a low molecular weight polyethylene or wax that sufficiently melts when heated to increase the releasability has also been used. However, although it is effective in preventing offset, a large amount is contained in a color toner. Adverse effects such as impairing the transparency of the OHP image, instability of the charging characteristics, and a decrease in durability are also recognized, and it is difficult to say that the transparency is sufficient.

In addition, as a problem peculiar to color copying, in particular, the color balance of at least three color toners, and preferably four colors, must be in harmony. Therefore, the respective colors are balanced in the fixing characteristics and color reproducibility. Must be something.

In principle, if there are three primary colors, yellow, magenta, and cyan, almost all colors should be able to be reproduced by the subtractive color mixing method, and therefore, full-color copying machines currently on the market Has a configuration in which three primary color toners are used in an overlapping manner. This should ideally allow any color to achieve any density range,
In reality, there are still points to be improved, such as the spectral reflection characteristics of the toner, the color mixing at the time of superimposing and fixing the toner, and the decrease in the saturation.

When black is obtained by superimposing three colors, three times more toner layers are formed on the transfer paper than in the case of a single color, as described above, and further, it is necessary to further reduce the offset resistance.

However, the present inventors have intensively studied to complement the improvement of the color toner and the improvement of the fixing device, and have found the following.

That is, when a pigment-based colorant is used for a color toner, contamination of the fixing roller is significantly reduced as compared with the case where a dye-based colorant is used. Therefore, the durability of the fixing roller is also improved. However, when only a pigment-based colorant is used, particularly for a magenta toner, the obtained image has poor chroma and poor color reproducibility.

Regarding magenta toner and fixing property, the applicant of the present invention
-15555-7, the use of a rhodamine-based basic dye alone or in combination with a pigment makes it possible to significantly improve the dyeing offset on the silicone rubber fixing roller as compared with the rhodamine-based oil-soluble dye. showed that.

However, as a result of detailed studies by the present inventors, regarding the use of a rhodamine-based basic dye alone, since it forms a salt that is easily dissociated in water, it is inferior in charging characteristics and affected by the environment such as temperature and humidity. I knew that I would be greatly affected.

The pigment / dye combination toner can increase the saturation, but has a drawback due to the combination.

Since the affinity between the dye and the pigment used is poor, they mutually repel each other in the binder resin during the dispersion step, making it difficult to make the color tone uniform. In addition, since the compatibility of each dye / pigment with the binder resin is not uniform, the two are not simultaneously in the same dispersion state, and the pigment is poorly dispersed or the dispersion time is too long. As a result, separation of the dye tends to occur. If the colorant unevenly distributed as described above is used as the toner, the charging characteristics of the electrophotography are inferior, and the cause of fogging, contamination due to scattering of the toner in the machine, and the translucency of the OHP image are also reduced. I understood that.

In the examples of JP-A-62-15555-7, a phenol resin is used as a charge control agent, and a combined use of a rhodamine-based basic dye and a pigment is used as a coloring agent, and the dyeing offset on a silicone rubber roller is reduced. It did not occur at all.

However, as described above, the dispersion of the colorant is poor,
A toner having poor charging characteristics has a property of easily aggregating. In particular, a phenomenon called "carrier pulling" occurs in which the toner adheres to the periphery of the carrier during development, and the carrier is developed together with the toner.

Therefore, the present inventors have conducted intensive studies, and in a pigment-dye combination system, by using a dye treated with a phenol resin, migration of the dye is prevented, color reproducibility is good, and fixing characteristics are good. Invented the color toner.

 This is presumed to be due to the following reasons.

The structure of the magenta toner according to the present invention is disclosed in
Nos. 555-7, which are similar to the examples described above, but in which a dye previously treated with a phenol resin is kneaded with a pigment and a binder resin to obtain a toner, and a pigment, a dye, a phenol resin and a binder are obtained. The dispersion state of the colorant is completely different from the case where the resin is kneaded at a time to obtain the toner. Although this is not clear, it is considered that the action between the phenol resin and the dye is changed by the presence of the pigment or the binder resin. This indicates that the effect of improving the fixability by adding the phenolic resin is not recognized, so that it is not effective to simply add the phenolic resin at the time of kneading.

As a result, even if the pigment / dye combination system and the phenol resin are contained as described above, the poor dispersion may cause a phenomenon such as "carrier pulling", and when the carrier passes through the fixing machine, In particular, in the case of a silicon rubber roller, the carrier is embedded in the rubber, and as a result, the life of the fixing roller is shortened.

Therefore, the fact that the dye is previously treated with the phenolic resin is different from the case in which the dye is treated in the form of a toner.

Further, in the fixing device including the fixing roller and the pressure roller, when the white paper is passed, the paper discharge direction is set to be higher than the vertical direction of the line connecting the center of the fixing roller and the pressure roller. It has been found that by setting it on the roller side, it is possible to prevent "fixation" of the fixed image surface by the fixing roller.

By using the fixing device and the color toner, it was found that a copied image having good color reproducibility was obtained, and the durability of the fixing roller could be drastically increased.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to provide a method for fixing a full-color toner image showing good fixability and color mixing in full-color copying.

Another object of the present invention is to provide a method for fixing a full-color toner image having a sufficient triboelectric charging property.

Another object of the present invention is to provide a method for fixing a full-color toner image having high gloss, which significantly improves image quality.

Another object of the present invention is to provide a method for fixing a full-color toner image which is hard to cause carrier spent even by repeated copying and has excellent durability.

Another purpose is to sufficiently prevent hot offset,
An object of the present invention is to provide a fixing method having a wide fixing temperature range.

Another object is to provide a fixing method in which the offset resistance is maintained even after repeated fixing.

[Means and Actions for Solving the Problems] Specifically, the present invention relates to a full-color image forming apparatus formed by multicolor electrophotography using at least two kinds of magenta toner, cyan toner, yellow toner and black toner. A fixing roller having a heating device and having a rubber-like elastic layer on a core, and a pressure roller having a heating device and having a rubber-like elastic layer on the core. A fixing method for fixing to a transfer material with a heat roller fixing device having: a magenta toner, a polyester resin particle containing a quinacridone pigment and a xanthene dye previously treated with a phenol resin, The cyan toner is a toner having a polyester resin particle containing a copper phthalocyanine-based blue pigment and a flow improver. The yellow toner is a toner having polyester resin particles containing an azo yellow pigment and a flow improver, and the black toner is a toner having polyester resin particles containing carbon black as a colorant and a flow improver. Use a heat roller fixing device with the hardness of the pressure roller higher than that of the fixing roller so that the paper discharge direction is closer to the pressure roller than the vertical direction of the line connecting the centers of the fixing roller and the pressure roller. Or a heat roller fixing device in which the diameter of the fixing roller is larger than the diameter of the pressure roller so that the paper discharge direction is closer to the pressure roller than the vertical direction of the line connecting the center of the fixing roller and the pressure roller. And a method for fixing a full-color toner image to a transfer material using the method.

 Hereinafter, the present invention will be described in detail.

The composition of the polyester resin for a full-color toner used in the present invention is as follows.

That is, in such a composition, 45 to 55 mol% of all components are alcohol components, and 55 to 45 mol% are acid components.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol,
Triethylene glycol, 1,5-pentanediol, 1,6-
Hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and a bisphenol derivative represented by the formula (A); (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2
Diols represented by the formula (B): And polyhydric alcohols such as glycerin, sorbit and sorbitan.

The divalent carboxylic acid containing 50 mol% or more of the total acid component includes phthalic acid, terephthalic acid, isophthalic acid,
Benzenedicarboxylic acids such as phthalic anhydride or anhydrides thereof; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, and further, succinic acid substituted with an alkyl group having 6 to 18 carbon atoms Or anhydrides thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, and anhydrides thereof; and the trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, Benzophenone tetracarboxylic acid and its anhydride are exemplified.

The alcohol component of the polyester resin particularly preferred in the practice of the present invention is a bisphenol derivative represented by the above formula (A), and the acid component is phthalic acid, terephthalic acid, isophthalic acid or anhydride thereof; succinic acid, n −
Examples include dodecenyl succinic acid or anhydride thereof, fumaric acid, maleic acid, dicarboxylic acids such as maleic anhydride, and trimetic acid or tricarboxylic acids of anhydride thereof.

This is because the polyester resins obtained with these acids and alcohols show sharp melting characteristics, have good color mixing properties as full-color toners and toners for fixing with heat rollers, and have excellent offset resistance.

Furthermore, the glass transition temperature of the polyester resin obtained here is 50 to 75 ° C., preferably 55 to 65 ° C., and the number average molecular weight n is 1,500 to 7,000, preferably 2,000 to 5,000, and the weight average molecular weight is 6,000 to 150,000. Is 10,000-100,0
Desirably it is 00.

The acid value is 90 or less, preferably 50 or less, the OH value is
It is desirably 50 or less, preferably 30 or less. This is because when the number of terminal groups in the molecular chain increases, the toner becomes more environmentally dependent on the charging characteristics of the toner when the toner is used.

The quinacridone pigment for magenta and the xanthene dye used in the present invention are as follows.

Representative examples of quinacridone pigments include: and so on. Among them, CI Pigment Red 122 is particularly suitable as a colorant for magenta.

Also, as typical examples of the xanthene dye used in the present invention, Is mentioned.

All have a clear bluish pink color.

, Are basic dyes and therefore have some hygroscopicity. Considering the compatibility with the resin, in the present invention, CISolvent Red is oil-soluble, has excellent compatibility with the resin, and has a large coloring power. 49. is particularly suitable.

The phenolic resin for treating a xanthene dye used in the present invention includes the following as a monomer constitution.

As phenols, phenol, cresol, xylenol, alkylphenol, paraphenylphenol, bisphenol A, etc., and as aldehydes,
All known materials such as formaldehyde, paraformaldehyde, hexamethylenetetramine, furfural and the like can be used.

Among them, it is particularly preferable to use a phenol resin which is a condensate of tert-butylphenol and formaldehyde since the dispersion state of the dye is good.

The method of pre-treating the xanthene dye with the phenol resin in the present invention includes: (1) a method of melt-kneading the xanthene dye and the phenol resin with a two-roll mill, a Banbury mixer, a kneader, a three-roll mill, or the like; A) dissolving the phenolic resin in an appropriate solvent, dissolving or dispersing the xanthene dye in the solvent, and then removing and drying the solvent; (3) dissolving and dispersing the xanthene dye in a mixture of phenol and formaldehyde, (4) A xanthene dye is dissolved and dispersed in a mixture of phenol and formaldehyde to form a novolak resin under an acid catalyst, and hexamethylenetetramine or the like is added thereto as a crosslinking agent. Curing method, and the like.

The xanthene dye pretreated with a phenolic resin by these methods is dried and pulverized, melt-kneaded with a polyester resin as a binder resin, and uniformly dispersed.

In the present invention, when treating a xanthene dye with a phenolic resin, the quinacridone pigment can also be dispersed and treated in the same manner as the xanthene dye.

Further, in the present invention, when a xanthene dye is treated with a phenol resin, the polyester resin can also be melted or dissolved at the time of melting, dissolving or dispersing the xanthene dye.

Examples of the copper phthalocyanine-based blue pigment used in the present invention include CI Pigment Blue 15, CI Pigment Blue 16,
CI pigment blue 17 or a phthalocyanine skeleton having a structure represented by the formula,
And copper phthalocyanine pigments which are individually substituted.

. Copper phthalocyanine pigment As the azo yellow pigment used in the present invention, CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 5, CI Pigment Yellow 6, CI Pigment Yellow 7, CI Pigment Yellow 10 CI Pigment Yellow 11, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, and CI Pigment Yellow 17.

As for the content, for the yellow toner which is sensitive to the transparency of the OHP film, the binder resin 100
12 parts by weight or less based on parts by weight, preferably 0.5 to
7 parts by weight is desirable.

If the amount exceeds 12 parts by weight, the reproducibility of green, red, which is a mixed color of yellow, and human skin color as an image is poor.

For other magenta and cyan color toners, the amount is preferably 15 parts by weight or less, more preferably 0.1 to 9 parts by weight, based on 100 parts by weight of the binder resin.

In particular, for a black toner using two or more colorants in combination, the addition of a total colorant amount of 20 parts by weight or more not only tends to cause spent to the carrier, but also causes a large amount of colorant to be exposed on the toner surface. As a result, the fusing of the toner to the drum and the anxiety of the fixing property also increase. Therefore, the amount of the colorant is preferably 3 to 15 parts by weight based on 100 parts by weight of the binder resin.

The particle size of the carbon black used as the colorant of the black toner is 50 to 70 mμ, preferably 50 to 60 mμ. The toner containing carbon black with a particle size of less than 50 mμ has a chromaticity that shifts to yellowish, not only does not provide a sharp black color, but also makes it extremely difficult to disperse carbon black. Becomes non-uniform. Therefore, the adhesion of the fluidity improver is deteriorated and the fluidity is significantly reduced, so that a good triboelectric charge cannot be obtained, resulting in fogging and toner scattering. Also, the particle size
If it exceeds 70 μm, the blackness of the carbon black is low, and an image showing a vivid black color cannot be obtained.

The oil absorption of this carbon black is 50-100cc /
100 g, preferably 60-80 cc / 100 g. If the oil absorption exceeds 100 cc / 100 g, the structure of the carbon black becomes longer, the conductivity increases, and the triboelectric charge of the toner decreases, causing fogging and scattering. If the oil absorption is less than 50 cc / 100 g, a high image density cannot be obtained.

The carbon black contained in the resin is a binder resin
2.1 to 10.0 parts by weight, preferably 3.0 parts by weight, per 100 parts by weight
~ 6.0 parts by weight. If the carbon black content is less than 2.1 parts by weight, a high image density cannot be obtained, and the uniformity of the solid portion decreases, and if it exceeds 10.0 parts by weight, a sufficient triboelectric charge cannot be obtained.

In the measurement of the physical properties of the carbon black, the particle size was measured by directly and selectively counting the particle size in a scanning electron micrograph.

 The method for measuring the oil absorption is as described below.

It is also preferable that the toner according to the present invention contains a charge control agent in order to stabilize the negative charge characteristics. At that time, a colorless or light-colored negative charge controlling agent which does not affect the color tone of the toner is preferable. Examples of the negative charge control agent include an organometallic complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex or a zinc complex of di-tert-butylsalicylic acid). When a negative charge control agent is blended in the toner, 0.1 to 100 parts by weight of the binder resin is used.
It is preferable to add 10 parts by weight, preferably 0.5 to 8 parts by weight.

Particle size distribution (colorant-containing resin particles having no flow improver such as silica, aluminum oxide, and titanium oxide described below) of the classified products of magenta toner, cyan toner, yellow toner, and black toner obtained using the above-described materials Is
The volume average particle diameter is 4.0 to 16.0 μm, preferably 6.0 to 14.0 μm, and the number average distribution of 5.04 μm or less is 50 from the copy image quality.
% Or less, preferably 40% or less, and 2% of the volume average distribution.
0.2 μm or more is 9% or less, preferably 5% or less;
Further, the ratio α (α = volume average particle diameter / number average particle diameter) of the volume average particle diameter to the number average particle diameter is desirably 1.7 or less, preferably 1.4 or less.

As the flow improver used in the present invention, any one can be used as long as it can be added to the colorant-containing resin particles to increase the flowability before and after the addition.

For example, a fluorine resin powder, that is, fine powder of vinylidene fluoride, fine powder of polytetrafluoroethylene, or the like; or a fatty acid metal salt, such as zinc stearate, calcium stearate, or lead stearate; or a metal oxide,
Aluminum oxide, titanium oxide, zinc oxide powder or the like; or finely divided silica, ie, wet-process silica, dry-process silica, a silane coupling agent to the silica,
Examples include treated silica that has been surface-treated with a titanium coupling agent, silicon oil, or the like.

Preferred flow improvers are fine powders produced by vapor phase oxidation of silicon halide compounds, so-called dry silica or fumed silica,
It is manufactured by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl Preferred examples of the flow improver include aluminum oxide and titanium oxide obtained in the same manner as in the above-mentioned production process.

The particle size is preferably in the range of 0.001 to 2 μm as an average primary particle size, and particularly preferably 0.002 to 2 μm.
It is preferable to use a fine powder within a range of 0.2 μm.

Commercially available fine silica powder produced by vapor phase oxidation of a silicon halide used in the present invention includes, for example, those commercially available under the following trade names.

AEROSIL 130 (Nippon Aerosil) 200 300 380 TT600 MOX170 MOX 80 COK 84 Ca-O-SiL M-5 (CABOT Co.) MS-7 MS-75 HS-5 EH-5 Wacker HDK N20 V15 (WACKER- CHEMIE GMBH) N20E T30 T40 DC Fine Silica (Dow Corning Co.) Fransol (Fransil) Further, treated silica fine powder obtained by hydrophobizing silica fine powder generated by gas phase oxidation of the silicon halide. More preferably, the body is used. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

The method for imparting hydrophobicity is provided by reacting with silica fine powder or chemically treating with an organic silicon compound that physically adsorbs.

As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule with terminal positions For example, dimethylpolysiloxane containing a hydroxyl group bonded to one Si unit may be used for each unit. These are used alone or as a mixture of two or more.

The particle size of the treated silica fine powder is 0.003-0.1μm
It is preferable to use those in the range of Commercial products include Taranox-500 (Talco), AEROSIL R-972
(Nippon Aerosil).

The amount added to the colorant-containing resin particles, the resin particles
0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight per 100 parts by weight
Parts by weight. If it is less than 0.01 part by weight, there is no effect on improving the fluidity, and if it exceeds 10 parts by weight, fogging and bleeding of letters,
Promote in-flight scattering.

The fixing device used in the present invention may be configured such that, when white paper is passed, the paper discharge direction is closer to the pressure roller side than the vertical direction of a line connecting the center of the fixing roller and the pressure roller. It can be used in the invention.

As a method of setting the paper discharge direction to the pressure roller side, for example, the hardness of the pressure roller is made higher than the hardness of the fixing roller. (As a method of increasing the hardness of the pressure roller,
(I) a method of using an elastic body having a hardness higher than that of the fixing roller attached to the cored bar, and (ii) when using the same elastic body as the fixing roller, by making the elastic body layer thickness of the fixing roller thinner. There is a method of making the roller hard. ) The diameter of the fixing roller is made larger than the diameter of the pressure roller.

Further, by mounting the heating device not only on the fixing roller side but also on the pressure roller side, it is possible to significantly reduce the "skew" as compared with the case where the heating device is mounted only on the fixing roller side.

As a fixing device incorporating these methods, for example, as a fixing roller, an elastic body is a silicone rubber-based RTV or LTV.
In order to reduce the swelling of the rubber due to a single-layer roller or fixing oil, a two-layer structure in which an HTV layer is provided in the lower layer and an RTV or LTV layer is provided in the upper layer to improve the wetting with the fixing oil is mentioned. , Its rubber hardness (JIS-A) is 30-70 degrees,
35-60 (when two layers are combined if two layers)
Degree, the layer thickness is 0.5 to 5 mm, preferably 1.0 to 3.5 mm, and the pressure roller has a hardness of 40 degrees or more, preferably
It may be a silicon rubber type, a fluoro rubber type or a Teflon coated type with a temperature of 50 degrees or more.

Further, as a fixing roller, a fixing roller having a two-layer structure such as a silicone rubber-fluororubber, a silicone rubber or a fluororubber-Teflon coating system, or a silicone rubber or a fluororubber is used for the purpose of improving fixing oil resistance and abrasion resistance. A material having a three-layer structure such as -Teflon coat-silicone rubber may be used, but in this case, it is important that the hardness is within the above-mentioned range.

The diameter of the fixing roller cannot be increased so much because the miniaturization of the copying machine is required. Further, when the diameter of the fixing roller is reduced, the nip cannot be taken sufficiently, so that the toner does not melt sufficiently, so that the color mixing property is deteriorated and the fixing speed has to be lowered in order to increase the color mixing property. Therefore, the diameter of the fixing roller and the pressure roller is 40 to 80.
mmφ is appropriate.

 Hereinafter, each measurement method in the present invention will be described.

(1) Measurement of glass transition temperature Tg In the present invention, measurement is performed using a differential thermal analysis measurement device (DSC measurement device), DSC-7 (manufactured by PerkinElmer).

The measurement sample is precisely weighed in an amount of 5 to 20 mg, preferably 10 mg.

Put this in an aluminum pan and use an empty aluminum pan as a reference.
The measurement is performed at normal temperature and normal humidity at a heating rate of 10 ° C./min.

In this heating process, an endothermic peak of a main peak in a temperature range of 40 to 100 ° C. is obtained.

The intersection of the line of the midpoint of the baseline before and after the endothermic peak appears and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

(2) Measurement of molecular weight distribution In the present invention, the molecular weight distribution was measured by high performance liquid chromatography (JASCO TRI ROTAR-VI HPLC system manufactured by JASCO Corporation). The column is Toso TSK gel-20 manufactured by Toyo Soda Industry Co., Ltd.
00, -3000, -4000, -5000 were used, and THF was used as a solvent.
The Detector was Shodex RISE-51 manufactured by Showa Denko KK, and the measurement conditions were as follows: Flow rate: 1.0 ml / min, column temperature: 40 ° C., Inj
vol.75μ.

The molecular weight of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number, based on the molecular weight distribution of the sample.

As a standard polystyrene sample for preparing a calibration curve, for example, a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.15 manufactured by Pressure Chemical Co. or Toyo Soda Industry Co., Ltd.
× 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶
It is appropriate to use at least about 10 standard polystyrene samples.

(3) Particle size distribution measurement Coulter counter TA-II type (manufactured by Coulter, Inc.) was used as the measuring device, and an interface (manufactured by Nikkaki) for outputting the number average distribution and volume average distribution and CX-1
A personal computer (manufactured by Canon Inc.) is connected, and a 1% aqueous NaCl solution is prepared using primary grade sodium chloride as an electrolyte.

As a measuring method, a surfactant as a dispersing agent, preferably 0.1 to 5 ml of an alkylbenzene sulfonate is added to the electrolytic aqueous solution of 100 to 150 ml, and a measurement sample of 0.5 to 50 mg is further added.
Add.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and a 100 μm aperture was used as the aperture by the Coulter Counter TA-II.
The volume average distribution and the number average distribution are obtained by measuring the particle size distribution of the particles of up to 40 μm.

From the obtained volume average distribution and number average distribution, respective values of the volume average particle diameter, the number average particle diameter, the number average distribution of 5.04 μm or less, and the volume average distribution of 20.2 μm or more are obtained.

(4) Measurement of oil absorption (DBP method) The oil absorption is measured in accordance with ASTM method D 2414-79.

Operate the faucet of the absorber meter and completely fill DBP (dibutyl phthalate) so that no air bubbles remain in the automatic burette system.

Spring tension 2.68kg / cm Rotor rotation speed 125rpm Scale of torque limit switch 5 Damper valve 0.150 Dropping speed of DBP 4ml / min After adjusting the dropping speed of DBP by actual measurement, put a certain amount of dry sample in the absorption meter mixing chamber , The buret counter is set to zero, and the switch is automatically turned on to start dropping. When the torque reaches the set point (5 in this case), the limit switch is activated and the dripping stops automatically,
The scale (V) of the bullet counter at that time is read, and the oil absorption is calculated by the following equation.

OA: Oil absorption (ml / 100g) V: DBP used up to the end point (limit switch operating point)
(Ml) W: Weight of dried sample (g) [Example] The present invention will be described in detail below with reference to examples.

Example 1 Polyester resin obtained by condensation of propoxylated bisphenol and fumaric acid (n = 3,000, w = 17,000, T
g = 57 ° C., acid value = 9.0, OH value = 17) A full-color toner was obtained using the coloring agent and the charge control agent in the amounts prescribed in Table 1 below based on 100 parts by weight.

The production method was performed by a master batch method. First,
Melt and knead the polyester resin and the colorant in an amount 6 times the amount of the colorant with a three-roll mill.
It was crushed in the following to obtain a colored resin for a master batch. Next, the polyester resin, the charge control agent, and the colored resin for the master batch were weighed so as to have the above-mentioned predetermined amounts, and were premixed by a Henschel mixer. Thereafter, the mixture is melted and kneaded with a three-roll mill, and after cooling, about 1 to 2 mm using a hammer mill.
The mixture was coarsely pulverized to an appropriate degree, and then finely pulverized to a particle size of 30 μm or less by a pulverizer using an air jet method. Further, the obtained finely pulverized product was classified, and for the magenta toner, the volume average particle size was 8.02 μm and the number average particle size was 6.20 μm (therefore, α
= 1.29), the number average distribution was adjusted to 30.0% for 5.04 μm or less, and the volume average distribution was adjusted to 20.0 μm or more for 0.0%. The particle size distributions of other toners are shown in Table 2. 0.5 parts by weight of silica fine powder treated with hexamethyldisilazane as a flow improver was added to 100 parts by weight of each classified product, and 0.2 parts by weight of aluminum oxide fine powder were externally added to obtain a full-color toner.

As a carrier, styrene-2-ethylhexyl acrylate-methyl methacrylate (copolymer weight ratio 50: 20: 3)
Using a Cu-Zn-Fe-based ferrite carrier coated with 0.5% by weight of (0) (average particle diameter 40 μm; 250 mesh pass, 400 mesh on 83% by weight), a developer was prepared so that the toner concentration of each color was 5% by weight. .

Using these developers and toners, an image output test was carried out with a remodeling machine (modification of a fixing device) of a Canon full-color copying machine CLC-1. As the fixing roller, a two-layer RTV / HTV silicone rubber with a rubber layer thickness of 3.0 mm, a hardness of 40 degrees and a fixing roller diameter of 40 mmφ is used. , Layer thickness 1mm, diameter
The thing of 40mmφ was used. The heating device was also attached to the pressure roller side. In a blank paper passing test using plain paper as the transfer material, the paper discharging direction was toward the pressure roller.

As a result of the image output test, there is no offset to the fixing roller even after printing 25,000 sheets in full-color mode, and the original color chart without fogging is faithfully reproduced, and the black image part has excellent opacity A vivid full-color image having a certain black color was obtained.

Example 2 Polyester resin obtained by condensation of propoxylated bisphenol, ethoxylated bisphenol, terephthalic acid and trimellitic acid (n = 3,500, w = 19,000, Tg
= 59 ° C., acid value = 10, OH value = 20) 100 parts by weight of the coloring agent and the charge control agent in the above prescribed amounts (Table 3), and the same procedure as in Example 1 was carried out. A classified toner having the particle size distribution shown in the table was prepared. As a flow improver, fine silica powder treated with hexamethyldisilazane was classified into each toner 100
0.5 parts by weight was externally added to parts by weight to obtain a full-color toner.

The carrier is vinylidene fluoride-tetrafluoroethylene copolymer (copolymerization weight ratio 8: 2) and styrene-
Cu-Zn-Fe-based ferrite carrier coated with 0.7% by weight of acrylic 2-ethylhexyl-methyl methacrylate (copolymerization ratio 45:20:35) at a weight ratio of 50:50 (average particle size)
Using a 49 μm, 250 mesh bath, 400 mesh on 91.0% by weight), a developer was prepared such that the toner concentration of each color became 9% by weight.

Using these developers and toners, the same full-color copier CLC-
An image-drawing test was performed on the sample No. 1.

As a result, even after printing 100,000 sheets in full-color mode, there is no offset to the fixing roller, and the original color chart without fog is faithfully reproduced, and the black image part has a deep black with excellent concealment. A colorful full-color image was obtained.

Example 3 The fixing roller was silicone rubber (HTV) -Teflon film coat (tetrafluoroethylene resin) -silicon rubber (LT
V) with a three-layer structure with a layer pressure of 2.0 mm, a hardness of 50 degrees, and a roller diameter of 60 mmφ. Thickness 1.0mm, hardness 60 degrees, roller diameter 60mm
The thing of φ was used. The heating device was also attached to the pressure roller side. In a blank paper passing test using this fixing device,
The discharge direction was on the pressure roller side. This fixing device was attached to Canon full color copier CLC-1,
An image output test was performed using the toner and the developer of Example 1.

As a result, the original color chart without fogging was completely reproduced without any offset to the fixing roller even after printing 2,000,000 sheets in full color mode, and the black image part exhibited deep black with excellent opacity. A colorful full-color image was obtained.

Example 4 The fixing roller was a two-layer RTV / HTV silicone rubber having a layer thickness of 2.0 mm, a hardness of 45 degrees, and a roller diameter of 80 mmφ. The pressure roller was a silicone rubber (HTV) -fluororubber rubber. A layered structure having a layer thickness of 1.0 mm, a hardness of 50 degrees and a roller diameter of 60 mm was used. The heating device was also attached to the pressure roller side. In a blank paper passing test using this fixing device, the paper discharging direction was toward the pressure roller.
This fixing device was attached to a Canon full-color copying machine CLC-1, and an image output test was performed using the toner and the developer of Example 1.

As a result, there is no offset to the fixing roller even after printing 30,000 sheets in full-color mode, and the original color chart without fogging is faithfully reproduced, and the black image part has a deep black with excellent opacity. A colorful full-color image was obtained.

Comparative Example 1 A classified magenta toner was prepared in the same manner as in Example 1 except that 1.2 parts by weight of CI Basic Violet 10 was used as a colorant for magenta toner (volume average particle size).
8.38μm, number average particle size 6.28μm (α = 1.33), number average distribution 5.04μm or less 29.1%, volume average distribution 20.2μm or more
0%). The other colors used in Example 1 were used.

Thereafter, an image-drawing test was performed in the same manner as in Example 1.

As a result, observing the fixing roller after printing for 5,000 sheets in the full-color mode, it was found that the carrier was embedded in the fixing roller due to the "carrier pulling" phenomenon. After a further 4,000 printing cycles, the fixed image had a rougher surface than the initial image.

Comparative Example 2 As a fixing roller, a two-layer fluororubber-teflon-coated (tetrafluoroethylene resin) having a hardness of 70 degrees, a layer thickness of 1.0 mm, and a roller diameter of 60 mmφ was used. (HTV) One layer, hardness 55
A roller having a thickness of 5.0 mm and a roller diameter of 60 mm was used. The heating device was attached only to the fixing roller side. In a blank paper passing test using this fixing device, the paper discharging direction was toward the fixing roller.

This fixing device is a Canon full color copier CLC-1.
And an image output test was performed using the toner and the developer of Example 1.

As a result, a so-called "offset jam", in which the image was wound around the fixing roller from the first image output, occurred, and the printing durability test could not be performed.

[Effects of the Invention] As described above, according to the method for fixing a full-color toner image of the present invention, an original color chart having no offset and no fog even after an image output test, for example, after 30,000 prints, is performed. A full-color image that faithfully reproduces the image can be obtained.

Further, the black image portion can obtain deep black with excellent concealment.

In addition, the toner transportability in the copying machine is good, a stable image density can be obtained, and a good image with little fog and toner scattering can be obtained.

[Brief description of the drawings]

FIG. 1 is a view illustrating a state in which a sheet is discharged from a direction perpendicular to a line connecting a center line of a fixing roller and a pressure roller to a pressure roller side in order to explain a feature of the present invention. It is.

Continuation of the front page (56) References JP-A-58-208775 (JP, A) JP-A-64-9466 (JP, A) JP-A-61-296376 (JP, A) JP-A-58-108256 (JP, A) , A) Japanese Patent Publication No. 51-24256 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/20 G03G 9/08

Claims (4)

(57) [Claims] 1. A full-color toner image formed by multicolor electrophotography using at least two kinds of magenta toner, cyan toner, yellow toner and black toner. Roller fixing device having a fixing roller having a rubber-like elastic material layer and a pressure roller having a rubber-like elastic material layer on a cored bar. The magenta toner is a toner having polyester resin particles containing a quinacridone pigment and a xanthene dye previously treated with a phenolic resin and a flow improver, and the cyan toner is copper phthalocyanine. A toner containing polyester resin particles containing a blue pigment and a flow improver, wherein the yellow toner contains an azo yellow pigment. The black toner is a toner having a polyester resin particle containing carbon black as a colorant and a flow improver, and the paper discharge direction is a fixing roller and a pressurizing roller. Use a heat roller fixing device in which the hardness of the pressure roller is higher than the hardness of the fixing roller so that it is closer to the pressure roller than the vertical direction of the line connecting the centers of the rollers, or the discharge direction is the fixing roller. Using a heat roller fixing device with the fixing roller diameter larger than the pressure roller diameter so that it is closer to the pressure roller side than the vertical direction of the line connecting the center of the pressure roller and
A method for fixing a full-color toner image, comprising fixing a full-color toner image to a transfer material. 2. A polyester resin comprising an alcohol component represented by the following formula (A): (Wherein R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10). Item 1
3. The method for fixing a full-color toner image described in 1. above. 3. The polyester resin has a glass transition point of 50 to 50.
The method for fixing a full-color toner image according to claim 1 or 2, wherein the temperature is 75 ° C, the number average molecular weight (Mn) is 1,500 to 7,000, and the weight average molecular weight (Mw) is 6,000 to 150,000. 4. The polyester resin has a glass transition point of 55 to 55.
The full-color toner image fixing method according to claim 1, wherein the temperature is 65 ° C., the number average molecular weight (Mn) is 2,000 to 5,000, and the weight average molecular weight (Mw) is 10,000 to 100,000.