JP2715313B2 - Electrophotographic toner - 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 an electrophotographic color toner that maintains the offset resistance to a fixing roller even during durability.

[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. As a toner used in such a developing method, a fine powder in which a dye or a pigment is dispersed in a natural or synthetic resin is conventionally used. Further, it is also 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 has been rapidly progressing, and two-color copiers and digitized full-color copiers have been launched in 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.

In the general method, first, an electrostatic latent image is formed on a photoconductive layer by passing light from an original through a color separation light transmission 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 property that the color toner should have is extremely important. Element.

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

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

As such satisfactory color toners, the present applicant has disclosed in Japanese Patent Application Laid-Open Nos. Sho 50-62442, 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, and have a hardness of 20 to 50 °, and in combination with a silicon rubber roller capable of applying silicone oil that is vulcanized at room temperature or low temperature while retaining elasticity, The shape of the toner changes to a state close to complete melting at the time of fixing, and preferable glossiness and color reproducibility are obtained. These effects are described in the 4th Non-impact Printing Technology Symposium, P129
As described in (1987), it means that the viscosity term is more important than the elastic term in the viscoelastic property of the binder resin as the fixing property of the toner.

That is, the toner at the time of heating behaves more viscously, has an increased thermal melting property, and has a glossiness. But,
Such a binder resin design emphasizing the viscosity term inevitably lowers the intermolecular cohesion at the time of heat melting, and also increases the adhesion of the toner to the heat roll when passing through the fixing device.
These cause a high-temperature offset phenomenon.

In particular, when a silicone rubber roller is used as a fixing roller, high-temperature offset is likely to occur due to a substantial reduction in the releasability of the silicone rubber surface due to repeated use, regardless of whether the oil for releasing is applied. In the initial stage of use of the silicone rubber roller, a certain degree of releasability can be maintained due to the smoothness and cleanliness of the roller surface. However, if the image area is large like a color image and the toner holding amount on the support is much larger than that of the black and white copy image, the releasability of the roller gradually decreases as color copy is continued to be copied. . The speed at which the releasability deteriorates reaches several times that of black and white copying. Further, since the toner itself has almost no elasticity as described above, it is ineffective for the anti-offset effect. From these, after only several thousand to tens of thousands of sheets, a toner film or a granular attachment is formed on the roller surface,
A so-called high-temperature offset occurs when the toner upper layer on the image surface is peeled off when passing through the heat roller.

Various measures have been tried 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, some measures have been taken, such as applying oil to the roller. Most of the heat roller fixing devices of currently commercialized copying machines 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.

Also, as a toner, a method of adding a low-molecular-weight polyethylene wax that sufficiently melts when heated to increase releasability has been used. Adverse effects such as impaired image transparency, unstable charging characteristics, and reduced durability are also recognized, and are not satisfactory.

Further, as a particular problem unique to color copying, the color balance of at least three color toners, preferably four colors, must be balanced, and it is meaningful to discuss the fixing characteristics and color reproducibility of only one color. Absent.

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. Has a configuration in which three primary color toners are used in an overlapping manner. By this, ideally all colors can be realized in all density ranges, but in reality, there are still points to be improved such as the spectral reflection characteristics of the toner, the color mixture at the time of superimposing and fixing the toner, and the reduction of the saturation. have.

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

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic toner which shows good fixability and color mixing in full-color copying.

Still another object is to provide an electrophotographic toner having a sufficient triboelectric charging property.

It is another object of the present invention to provide an electrophotographic toner capable of forming a flat fixed image surface which significantly improves color image quality.

It is another object of the present invention to provide an electrophotographic toner which is hard to be spent on a carrier even by repeated copying and has excellent durability.

Another object of the present invention is to provide an electrophotographic toner in which high-temperature offset is sufficiently prevented and the fixing temperature range is wide.

Another object of the present invention is to provide an electrophotographic toner that maintains the offset resistance even after repeated fixing paper passing.

It is another object of the present invention to provide a heat roller-fixable electrophotographic toner which has excellent fluidity, does not cause aggregation, and has excellent impact resistance.

Means and Action for Solving the Problems In order to solve the above-mentioned drawbacks, the present inventors have focused on a binder resin for a color toner, particularly a polyester resin, and advanced the composition thereof, thereby completing the present invention. Hit.

That is, a novel polyester resin which does not impair the color reproducibility and glossiness of a color copied image and has offset resistance even when a fixing roller is used, and silicone rubber whose releasability has been reduced by repeated copying has been found.

Specifically, the present invention provides a toner comprising at least a polyester resin and a colorant, wherein a divalent or higher carboxylic acid or / and a lower ester thereof is used as an acid component for forming the polyester resin, and an ether is used as a diol component. A toner for electrophotography, wherein a polymer represented by the following general formula (1) is used as the other acid component or alcohol component using a modified diphenol.

Wherein, X and Y represents a -COOH or -OH, R _n H styrene derivatives, vinyl benzoate compounds,
Unsaturated diolefins, vinyl esters, α-methylene aliphatic monocarboxylic esters, acrylic esters, vinyl ethers, vinyl ketones, nitrogen-containing aromatic vinyl compounds, vinyl naphthalenes, acrylic acid derivatives, methacrylic acid Derivative, acrolein, vinylsulfones, vinylsulfonamides and cycloalkanevinyl compounds show one or two or more polymers selected from the group consisting of vinyl compounds, m represents 0 to 5, n represents 5 to 50,000 Show. ].

Examples of the carboxylic acid component comprising a divalent or higher carboxylic acid and a lower ester in the present invention include fumaric acid,
Maleic acid, maleic anhydride, phthalic acid, terephthalic acid, malonic acid, glutaric acid, n-butylsuccinic acid, n-
Octyl succinic acid, iso-dodecyl succinic acid, n-dodecenyl succinic acid, and 1,2,4 benzenetricarboxylic acid,
1,2,5 benzenetricarboxylic acid, 1,2,4 cyclohexanetricarboxylic acid, 2,5,7 naphthalenetricarboxylic acid, 1,2,4
Naphthalene tricarboxylic acid, 1,2,4 butane tricarboxylic acid, 1,2,5 hexane tricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxyl propane, 1,3-dicarboxyl-2-methyl-2-methylene carboxyl Propane, tetra (methylenecarboxyl) methane, 1,2,7,
8-octanetetracarboxylic acid or the like can be used.

Particularly preferred divalent or higher carboxylic acids include fumaric acid, terephthalic acid, n-dodecenylsuccinic acid, n-butylsuccinic acid, trimellitic acid, pyromellitic acid and lower esters thereof.

In the present invention, the etherified diphenol is preferably represented by the following formula: Is a bisphenol derivative or a substituted product. For example, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,2) -2,2-bis (4
-Hydroxyphenyl) propane and the like.

This is because the use of the etherified diphenol described above as an alcohol component other than the polymer described below does not only impair the smoothness of the fixing surface when the toner is used, but also can increase the fixing temperature range, This is because the charge characteristics of the toner for electrophotography are improved, and a toner having excellent fluidity, no aggregation, and excellent impact resistance is obtained.

The other diol or dicarboxylic acid component in the present invention is a polymer represented by the following general formula (1).

m = 0~5 n = 5~50,000 X, Y; -COOH or -OH R _n H, for example, styrene, o- methyl styrene,
m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p- n-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, o-methoxystyrene, p-methoxystyrene, p-chlorostyrene, 3,4
Styrene derivatives such as dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene, etc .; o
-Vinyl benzoate compounds such as vinylbenzoic acid, m-vinylbenzoic acid and p-vinylbenzoic acid; unsaturated diolefins such as butadiene and isoprene; vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride. Vinyl halides; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacryl Α such as dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate
-Methylene aliphatic monocarboxylic esters; methyl acrylate, ethyl acrylate, n-butyl acrylate;
Isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylate
Ethylhexyl, stearyl acrylate, acrylic acid 2
Acrylates such as chloroethyl and phenyl acrylate; maleic acid, maleic acid half ester;
Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole;
N-vinyl carbazole, N-vinyl indole, N-
Vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, 3-vinylpiperidine, vinylpyrazine, 2-
Nitrogen-containing aromatic vinyl compounds such as vinyl quinoline, N-vinyl phthalimide and vinyl imidazole; vinyl naphthalenes such as α-vinyl naphthalene; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; vinyl sulfone; Sulfone-containing vinyl compounds such as vinylsulfonamide; cycloalkanevinyl compounds such as vinylcyclopropane and vinylcyclohexane; and the like. In general, radically or anionically or cationically polymerized monomers are exemplified. A monomer is selected and polymerized.

As a method of obtaining a polymer, a mercaptan-based diol or dicarboxylic acid is allowed to act on the above-described monomer,
This is a generally known method using a living polymerization method or a radical polymerization method.

In the polymer represented by the general formula (1) obtained by this method, m is from 0 to 5, preferably from 0 to 3, and n is from 5 to 50,000, preferably from 20 to 20,000. Is more desirable for the purpose of maintaining the smoothness of the toner fixing surface and expanding the fixing temperature range. Also, this polymer is 45 ~
It is desirable that the content of the acid contained in 55 mol% or the alcohol contained in 55 to 45 mol% is 2 to 90 mol%, preferably 4 to 80 mol% in all the polyester components. The content of this polymer described here was measured by measuring the acid value or the OH value of the polymer by the method of measuring the acid value or the OH value of the polymer, was calculated as 1/2 of the mole number, and was subjected to condensation polymerization. Quantity.

The so-called grafted polymer represented by the general formula (1) having an appropriate length in the polyester skeleton has an effect of increasing the elasticity without changing the viscosity unlike the viscoelasticity of the conventional polyester, Therefore, it is considered that the fixing temperature range is expanded without impairing the smoothness of the fixing surface for full-color toner. From the above, when the number of n in the general formula exceeds 50,000, it is difficult to obtain the effect of increasing the elasticity without changing the viscosity, and it is difficult to increase the viscosity. If n is less than 5, the effect of increasing the elasticity is lost. If this polymer is less than 2 mol% in the total acid alcohol component, there is no effect of increasing the elasticity, and if it is 90 mol% or more, the viscosity is also increased and the smoothness of the fixing surface of the toner is lost. When m is 6 or more, the production process of the mercaptan compound becomes complicated, and it is difficult to obtain a stable and high-purity product.

In the present invention, the diol and / or dicarboxylic acid component which can further exert the effect, and as the polymer represented by the general formula (1), the following (I) to (I)
V) is preferred.

The reason is that the combination of styrene and acrylate, especially styrene and n-butyl methacrylate, and the combination of acrylonitrile and butadiene can easily control the number of n in the general formula (1) even if the ratio of each monomer is changed. is there. Another reason is that although the polymer obtained by the combination of the monomers is branched from the polyester main chain to form a so-called graft polymer, the fixing temperature range is wide and the fixing surface has excellent smoothness. It is in. Another reason is that a polyester using a polymer obtained by combining the above-mentioned monomers has excellent charging characteristics. Another reason is that, when etherified diphenol is used as the alcohol component, in combination with the polymer, the toner has excellent fluidity, does not cause aggregation, and has excellent impact resistance. Is to be.

Here, the ratio of styrene to n-butyl methacrylate is a molar ratio of 0 to 95/5, preferably 0 to 80/20, and the ratio of acrylonitrile to butadiene is 10/90 to 95/5, preferably 20/90.
80 to 90/10.

Further, the glass transition temperature of the obtained polyester resin is 55 to 70 ° C, and the acid value thereof is 1.0 to 90, preferably 2.0 to 90 ° C.
Preferably it is 50. If the acid value is 1.0 or less, the number of functional groups contributing to triboelectric charging decreases, and charging tends to be insufficient. If it is 90 or more, the affinity with water increases,
This is because the moisture resistance deteriorates.

As a method for producing a polyester resin, the polyester resin can be obtained by a conventionally known condensation polymerization method using the above-mentioned compound or the like as a composition component.

For example, an acid and a glycol component are charged into a reaction vessel equipped with a stirrer, a condenser, and a thermometer. Then, an inert gas (often nitrogen gas) is introduced to replace the air. The mixture system is heated to a predetermined temperature. At this time, a considerable amount of heat may be generated at the start of the esterification.

When the temperature reaches a predetermined temperature, the reaction is continued while measuring the acid value and viscosity of the ester until the esterification is at a preferable position. At the end of the reaction, the temperature of the reactor is lowered, the reaction is stopped, and cooled to room temperature to obtain a polyester resin.

Colorants suitable for the purpose of the present invention include the following pigments or dyes. In the present invention, light resistance is poor.
CIDisperse Y164, CISolvent Y77 and CISolvent Y
Colorants such as 93 are unrecognizable.

As the dye, for example, CI Direct Red 1, CI
Direct Red 4, CI Acid Red 1, CI Basic Red 1, CI Modern Red 30, CI Direct Blue 1, CI Direct Blue 2, CI Acid Blue 9, CI Acid Blue 15, CI Basic Blue 3, CI Basic Blue 5, CI Modant Blue 7, etc.

As the pigment, naphthol yellow S, Hansa yellow G, permanent yellow NCG, permanent orange GTR, pyrazolone orange, benzidine orange G,
Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue BC
Etc.

Preferably, disazo yellow, insoluble azo and copper phthalocyanine are suitable as pigments, and basic dyes and oil-soluble dyes are suitable as dyes.

Particularly preferably, CI Pigment Yellow 17, CI Pigment Yellow 15, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 12, CI
Pigment Tread 5, CI Pigment Red 3, CI
Pigment Red 2, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Blue 15, CI Pigment Blue 16, or a copper phthalocyanine having the structural formula (2) shown below and having a phthalocyanine skeleton substituted with two or three substituents. Pigments and the like.

R, R ': unless However alkylene group having 1 to 5 carbon atoms, all the X ₁ to X ₄ is -H.

Structural formula (2) The dyes include CI Solvent Red 49, CI Solvent Red 52, CI Solvent Red 109, CI Basic Red 12, CI Basic Red 1, and CI Basic Red 3b.

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.

When the amount is 12 parts by weight or more, the reproducibility of green, red, which is a mixed color of yellow, and human flesh 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.

Examples of the carrier used in the present invention include, for example, surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt,
Metals such as manganese, chromium, and rare earths and alloys or oxides thereof and ferrites can be used. There is no particular restriction on the manufacturing method.

Further, the system for coating the surface of the carrier with a resin or the like,
Particularly preferred in the J / B developing method described above. As the method, any conventionally known method such as a method of dissolving or suspending a coating material such as a resin in a solvent, coating and adhering to a carrier, and a method of simply mixing with a powder can be applied.

The fixing substance on the carrier surface varies depending on the toner material. Examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of di-tert-butylsalicylic acid, and styrene resin. It is suitable to use one or more of acrylic resin, polyamide, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dyes and lakes, silica fine powder, alumina fine powder, etc., but it is not necessarily limited thereto. .

The amount of the compound to be treated may be appropriately determined so that the carrier satisfies the above conditions, but is generally desirably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier of the present invention.

The average particle size of these carriers is 20-100 μm, preferably 2 μm.
It is preferred to have 5 to 70μ, more preferably 25 to 65μ.

A particularly preferred embodiment is a ternary ferrite of Cu-Zn-Fe, the surface of which is a combination of a resin such as a fluorinated resin and a styrene-type resin, for example, polyvinylidene fluoride and a styrene-methyl methacrylate resin; Fluoroethylene and styrene-methyl methacrylate resin, fluorine-based copolymer and styrene-based copolymer; such as 90:10 to 20:80, preferably a mixture of 70:30 to 30:70, 0.01-5% by weight, preferably 0.1-1
A coated ferrite carrier having the above-mentioned average particle diameter, in which the carrier particles are 250% by weight, coated with 250 mesh, and 350 mesh on, is 70% by weight. Examples of the fluorine-based copolymer include vinylidene fluoride-tetrafluoroethylene copolymer (10; 90 to 90:10), and examples of the styrene-based copolymer include styrene-2-ethylhexyl acrylate (20:80 to 90). 80:20), styrene-2-ethylhexyl acrylate-methyl methacrylate (20
To 60: 5 to 30:10 to 50).

The coated ferrite carrier has a sharp particle size distribution, provides favorable triboelectric charging properties to the toner of the present invention, and has the effect of improving electrophotographic properties.

When preparing a two-component developer by mixing with the toner according to the present invention, the mixing ratio is as a toner concentration in the developer,
5.0% to 15% by weight, preferably 6% to 13% by weight
In general, good results are obtained. 5.0 toner density
If the content is less than 15% by weight, the image density is low, making it impractical. If the content is more than 15% by weight, fog and scattering inside the machine are increased, and the useful life of the developer is shortened.

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, fluorine resin powders, such as vinylidene fluoride fine powder, polytetrafluoroethylene fine powder, and the like; or fatty acid metal salts, such as zinc stearate, calcium stearate, and lead stearate; or metal oxides, such as zinc oxide powder; Or finely divided silica,
That is, there are wet-process silica, dry-process silica, and treated silica obtained by subjecting the silica to a surface treatment with a silane coupling agent, a titanium coupling agent, silicon oil, or the like.

Preferred flow improvers are fine powders produced by vapor phase oxidation of silicon halides, so-called dry silica or fumed silica, which are produced by a conventionally known technique.

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 the amount is less than 0.01 part by weight, there is no effect on improving the fluidity.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples. All parts are parts by weight.

Example 1 A cyan color toner was obtained using the following amounts of the coloring agent and the charge control agent with respect to 100 parts of the polyester resin A in Table 1.

As the polymer (II) in Table 1, as the polymer (II) on page 20
A polymer having a mean degree of polymerization of about 100 was used. Further, as the polymer (III) in Table 1, a polymer represented by the formula (III) on page 10 is used, and n is from 140 to 260.
A mixture having an average degree of polymerization of about 200 was used.

The manufacturing method is that the above formulation amounts are preliminarily mixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, roughly ground to about 1 to 2 mm using a hammer mill, and then air-jetted. By pulverizer in 40
It was pulverized to a particle size of not more than μm. Further, the obtained finely pulverized product is classified and selected so that the volume average particle size becomes 4 to 15μ, and 0.5 parts of silica fine powder treated with hexamethyldisilazane as a flow improver is added to 100 parts of the classified product. This was added to obtain a cyan color toner.

Also, 8 to 12 parts of this color toner were coated with a vinylidene fluoride polymer and styrene-methyl methacrylate (copolymer weight ratio 65:35) in a weight ratio of 40:60 by about 0.35% by weight, and Cu-Zn- A Fe-based ferrite carrier (average particle size: 48 μm; 250 mesh pass, 350 mesh on 79%; true density: 4.5 g / cm ³ ) was mixed to a total amount of 100 parts to prepare a developer. The developer concentration was 10% by weight.

A copy test was performed using a color electrophotographic apparatus having an OPC photosensitive drum shown in FIG.

At this time, the fixing roll used in the fixing device 7 was a HTV silicone rubber layer having a thickness of 3 mm on a cored bar, and the pressing roll used a 3 mm HTV silicone rubber.

Further, the developer of the present invention has a constant developer amount by the developer regulating blade on the developing sleeve, and the J / B developing method is used in the opposed portion of the photosensitive drum 1 having the negatively charged electrostatic latent image. The negatively charged toner is transferred onto the photosensitive drum by the reaction developing method. In this embodiment, the distance between the sleeve and the photosensitive drum in the developing area is set to 450 μm. Using this method, a cyan image that faithfully reproduces the fog-free original even after printing for 50 000 sheets was obtained. Further, the conveyance in the copying machine and the detection of the developer density were good, and a stable image density was obtained. No offset to the fixing roller occurred at all even in repeated copying of 20 000 sheets.

Example 2 A magenta image was obtained in the same manner as in Example 1 with the above prescription.

The obtained product was a vivid magenta color having a high image density. Next, a printing durability test was performed. As a result, no toner offset or wrapping around the fixing roller occurred at all even after 80,000 sheets had been printed, and a good image without roughness was obtained.

Example 3 A test was conducted in the same manner as in Example 1 except that the colorant was changed to 3.2 parts of CI Pigment Yellow 15 using the polyester resin C shown in Table 1. As a result, there was no offset to the fixing roller even after 70,000 sheets.

Example 4 Using the color toners of cyan, magenta, and yellow obtained from Examples 1 to 3, full-color copying was performed by the color electrophotographic apparatus shown in FIG. 1 in the transfer order of magenta, cyan, and yellow. At this time, the fixing roll is an LTV silicone rubber layer having a thickness of 1.5 mm on the core metal, and the pressure roll is
It has a thin layer of fluororesin of 10 μ or less on HTV silicone rubber of 1.0 mm.

Even after the full-color copying of 50 thousand sheets, the image obtained a color copy with excellent saturation which was not different from the initial one. In the case of full-color copying, there are many three-color superimposed parts on the image,
The load on offset and durability was much greater than in the case of copying a single color, but in this test, the offset resistance of the fixing roller was almost the same as the initial one even after 50000 sheets.

Comparative Example 1 Except for the polyester resin D shown in Table 1, repeated full-color transfer was carried out in the same manner as in Example 4, and an offset occurred on only 6000 sheets, making it impractical.

Further, the fixing roll was subjected to thermal deterioration, and the material of the roll was separated from the core metal.

At a set temperature of about 160 ° C. below the heat resistance limit of the HTV silicone rubber, the toner of this comparative example was a fixed full-color image with insufficient fixation and low saturation.

For this reason, the repeated copying durability test was performed at a set temperature of 215 ° C. so that a practical image could be obtained.

Comparative Example 2 A full-color printing test was performed in Example 4, except that the binder resin of each toner was changed to a styrene-butyl methacrylate copolymer (softening point: 110 ° C.).

The initial image was a full-color image with a slight dullness.

Approximately 3,000 sheets, point-like offsets began to form on the fixing roller, and after 4,000 sheets, several offsets occurred in the circumferential direction of the fixing roller, streaky defects appeared on the image, and it was impractical became.

Measurement of softening point by flow tester Use flow tester CFT-500 type (manufactured by Shimadzu Corporation). A sample weighs about 1.0 to 1.5 g of a 60 mesh pass product.
This is pressed for 1 minute at a load of 100 kg / cm ² using a molding machine.

This pressurized sample is subjected to a flow tester measurement under the following conditions under normal temperature and normal humidity (temperature: about 20 to 30 ° C., humidity: 30 to 70% RH) to obtain a temperature-plunger drop curve. Obtained S
The temperature for the half of the plunger descent amount is determined from the V-shaped curve, and this is used as the softening point of the sample.

Measurement conditions: RATE TEMP 6.0 D / M (° C for 1 minute) SET TEMP 70.0 DEG (° C) MAX TEMP 200.0 DEG INTERVAL 3.0 DEG PREHEAT 300.0 SEC (seconds) LOAD 20.0 KGF (kg) DIE (DIA) 1.0 MM (mm) DIE (LENG) 1.0 MM PLUNGER 1.0CM ² (cm ² ) Method for measuring acid value ^{2 to 10} g of sample is weighed into a 200 to 300 ml Erlenmeyer flask, and about 50 ml of a 30:70 mixed solvent of methanol and toluene is added to dissolve the resin. I do. If solubility is poor, a small amount of acetone may be added. Using a mixed indicator of 0.1% bromthymol blue and phenol red, titrate with a pre-labeled N / 10 potassium-alcohol solution,
The acid value is calculated by the following calculation from the consumption of the alcoholic potash solution.

Acid value = KOH (ml) × N × 56.1 / Sample weight (where N is a factor of N / 10 KOH) [Effect of the Invention] As described above, according to the present invention, a clear and high-quality image is provided for a long time. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a color electrophotographic copying machine to which the color toner of the present invention is applied.

Claims (1)

(57) [Claims] 1. A toner comprising at least a polyester resin and a colorant, wherein a divalent or higher carboxylic acid and / or a lower ester thereof is used as an acid component for forming the polyester resin, and an etherified diphenol is used as a diol component. An electrophotographic toner, wherein a polymer represented by the following general formula (1) is used as another acid component or alcohol component. Wherein, X and Y represents a -COOH or -OH, R _n H styrene derivatives, vinyl benzoate compounds,
Unsaturated diolefins, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, acrylic esters, vinyl ethers, vinyl ketones, nitrogen-containing aromatic vinyl compounds, vinyl naphthalenes, acrylic acid derivatives, methacrylic acid Derivative, acrolein, vinylsulfone, vinylsulfonamide and cycloalkanevinyl compound show one or two or more polymers selected from the group consisting of vinyl compounds, m represents 0 to 5, n represents 5 to 50,000 Show. ]