JPH1124313A - Electrophotographic color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a full-color toner which shows good fixing property, high gloss and transparency without applying oil on a fixing roller and which sufficiently prevents high temp. offset. SOLUTION: This toner consists of at least two kinds of binder resins, a coloring agent and a wax. The two kinds of binder resins consist of a binder resin (A) having 1×10<4> to 5×10<4> weight average mol.wt. (Mw), 2 to 5 ratio (Mw/Mn) of Mw to number average mol.wt. (Mn), and 90 to 100 deg.C softening point, and a binder resin (B) having 2×10<4> to 10×10<4> Mw, 3.5 to 10 Mw/Mn and 105 to 135 deg.C softening point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for electrophotography which does not require oil for a fixing device.

[0002]

2. Description of the Related Art In recent years, the development of hard copy technology using an electrophotographic system has been rapidly expanding from black and white to full color, and the full color market has been particularly expanding. Color image formation by full-color electrophotography generally reproduces all colors using three primary color toners of three 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 a color electrophotography method in which such development is performed a plurality of times and a plurality of toner images of different colors are superimposed 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 due to toner particles as much as possible and have appropriate glossiness and luster.
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.

On the other hand, a fixing device used for fixing a color toner uses a roller made of a material having excellent surface releasability, but in most cases, the roller surface is coated with oil. However, the application of a large amount of oil to enhance the releasability has problems such as oil contamination of transfer paper, cost increase, and space for a tank for storing oil is required, and the fixing device becomes large. Generally, the reason why oil is applied to fix a color toner is as follows. That is, in general, a color toner needs to have higher heat melting property, lower viscosity, and higher gloss and transparency than black toner for black-and-white printing during fixing and heating. However, the toner using such a resin tends to decrease the intermolecular cohesion during heat melting, so that the toner adheres to the heat roller when passing through the fixing heat roller, and a high-temperature offset phenomenon occurs. I do. Therefore, in order to prevent the high-temperature offset, it is common to apply oil to the fixing roller to reduce the adhesion of the toner to the fixing roller. Further, a so-called oilless toner in which oil is not applied to the fixing roller has been tried, and it has been generally proposed to disperse wax in the toner.

However, in the case of a color toner, it is necessary to sufficiently exude wax from the toner whose viscosity has been reduced as described above, and it is difficult to prevent offset. In the case of a high-viscosity toner such as a black toner for black-and-white printing, since the intermolecular cohesion at the time of hot melting of the toner is high, offset can be prevented by exuding a small amount of wax, but sufficient toner Melting is not performed, and gloss and transparency are insufficient. From the above, at present, a color toner that can be used in a fixing device that does not use oil and has offset resistance, sufficient gloss, and transparency has not been obtained.

For example, Japanese Patent Publication No. Hei 8-12475 discloses an etherified diphenol component, a divalent carboxylic acid or a derivative thereof substituted with a hydrocarbon group, a trivalent or higher polycarboxylic acid and / or a polyol acid, or JP-A-51-144625 describes a color toner using a polyester resin having its derivative component and having a limited apparent viscosity and DSC endothermic peak.
A polyester resin of 0 to 150 ° C and a molecular weight of 500 to 2
Magenta toner obtained by adding a certain pigment to a resin mixture of 2,000 solid silicone varnishes;
JP-A-158281 discloses a toner using a binder resin having a haze value of 7 to 30% of a dispersion liquid. These toners use a weakly cross-linked resin as a binder resin, but use an oil. And the offset resistance is insufficient.

JP-A-5-158282 discloses a divalent aromatic acid component (a) selected from isophthalic acid, terephthalic acid and derivatives thereof, and a trivalent aromatic acid component selected from trimellitic acid and derivatives thereof. From a divalent aromatic acid component (b), a divalent acid component (c) selected from dodecenylsuccinic acid, octylsuccinic acid and anhydrides thereof, and a propoxylated or / and ethoxylated etherified diphenol (d). Produced, hydroxyl value 10-20, Mw: 1
3000-20,000, Mn: 5000-8000, M
A color toner containing a polyester resin having w / Mn = 2 to 3.5 and a color image forming method are described.
However, according to this technique, the offset resistance in oil-less is insufficient.

Japanese Patent Application Laid-Open No. 7-219274 discloses a pigment-dispersed resin which is prepared by mixing a water-containing paste of a polyolefin wax and a pigment into a pigment-dispersing resin solution and then heating the pigment-dispersed resin. JP-A-7-31479 describes a color toner in which the difference in SP value of the resin is 1.5 to 0.5 and the polyolefin wax is highly dispersed in the binder resin. The use of such a toner and the use of an elastic layer coated with a fluororesin on the surface layer as a fixing roller are described, but only the effect of polyolefin wax is expected to impart oillessness. Is not enough.

[0008] JP-A-7-333903 discloses M
n: 2500-3500, Mw: 50,000-3000
Although a polyester resin-containing toner containing no THF (tetrahydrofuran) -insoluble content of 00 is described, however, this case also requires a trace amount of oil application,
Oil-less conversion is inadequate.

Japanese Patent Application Laid-Open No. 7-333903 discloses a method in which a polyester resin having a wax and a THF insoluble content of 15 to 40% and a polyhydric alcohol component is limited, and the difference in the refractive index between the binder resin and the wax is limited. However, it is difficult to obtain high gloss due to a large amount of THF insolubles.

Japanese Patent Application Laid-Open No. 8-503367 discloses that in a wax-containing toner, the molecular weight of the wax is 350 to 8
Having a maximum value in the range of 50 and 900 to 4000,
Although an ester wax-containing toner having Mw: 350 to 4000 and Mn: 200 to 4000 is described, sufficient oillessness cannot be obtained only by limiting the properties of the wax.

JP-A-8-50368 discloses that an ester compound having the same total carbon number is 50 to 95% by weight.
Although a wax-containing toner contained in an ester wax is described, sufficient oillessness cannot be obtained only by limiting the properties of the wax.

JP-A-3-39971 discloses that no toluene-insoluble matter is contained and the molecular weight is 500 to 2,000,
It has a peak in the range of 100 to 100,000, and Mw: 10
000-80000, Mn: 1500-8000, M
Although a resin-containing color toner with w / Mn> 3 is described, the oil-less method is insufficient.

Japanese Patent Application Laid-Open No. 4-57062 discloses that the softening temperature of a flow tester having a melt viscosity of 10 ⁵ poise is 90 to 12;
At 0 ° C., Mw: 1.5 × 10 ^{4 to} 5 × 10 ⁴ , Mn: 2 ×
A resin-containing color toner having a density of 10 ³ to 1 × 10 ⁴ and Mw / Mn = 5 to 15 is described, however, in this case, too, the oillessness is insufficient.

[0014]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a full-color toner for electrophotography in view of the above-mentioned prior art, which shows good fixability without applying oil to a fixing roller and has a high glossiness. Another object of the present invention is to provide a full-color toner having high transparency and sufficiently preventing high-temperature offset.

[0015]

Means for Solving the Problems The object of the present invention is to provide (1) an electrophotographic color toner comprising at least two kinds of binder resins, a colorant and a wax, wherein the two kinds of binder resins are Weight average molecular weight (Mw) of 10,000 to 5
000, and the ratio to the number average molecular weight (Mn) (Mw / M
n) having a binder resin A having a softening point of 2 to 5 and a softening point of 90 to 100 ° C., Mw of 20,000 to 100,000, and Mw / Mn of 3.5 to
10. A color toner for electrophotography, comprising a binder resin B having a softening point of 105 to 135 ° C. (2) “The color toner for electrophotography according to the above (1), wherein the binder resins A and B are made of any one of a polyester resin and a polyol resin.”, (3) "The wax is incompatible with the binder resin, is an ester or olefin, and has a melting point of 65 to 90.
The color toner for electrophotography according to the item (1), wherein the temperature is ° C. (4) The electrophotographic color toner according to (1), wherein the wax has an average dispersed particle size in the binder resin of 0.3 to 3 μm. You.

Hereinafter, the contents of the present invention will be specifically described.
As a result of investigations by the present inventors in a pressure fixing method using a heat fixing roller for obtaining a color image in electrophotography, the use of the color toner having the configuration described in the above (1) allows the fixing roller to be used. Sufficient offset resistance can be obtained without applying oil. That is, the weight average molecular weight (Mw) is 10,000 to 5
000, and the ratio to the number average molecular weight (Mn) (Mw / M
n) having a binder resin A having a softening point of 2 to 5 and a softening point of 90 to 100 ° C., Mw of 20,000 to 100,000, and Mw / Mn of 3.5 to
10, and the binder resin B having a softening point of 105 to 135 ° C. is combined, so that the toner has a low viscosity at the time of fixing,
Since sufficient melting occurs, it becomes possible to obtain gloss and transparency, and furthermore, the cohesive force between molecules is hardly reduced, and offset is hardly generated.

Further, the Mw of the binder resins A and B is preferably in the above range. If the Mw is lower than the above range, offset tends to occur, and furthermore, blocking tends to occur during storage of the toner. Become. Also, Mw /
The same applies when Mn is smaller than the above range or when the softening point is lower than the above range. Conversely, Mw
Is high, the Mw / Mn is wide, and the softening point is high, the gloss and transparency become insufficient. Further, by setting the compounding ratio of the binder resins A and B to a weight ratio of 20:80 to 80:20, the object of the present invention can be sufficiently achieved.

On the other hand, when one kind of binder resin is used and a resin having an intermediate property of the above binder resin is used, it is difficult to obtain sufficient offset resistance, gloss and transparency. Further, the binder resin used is, in particular, a polyester resin and / or
Alternatively, the object of the present invention can be more satisfactorily achieved by using any one of the polyol resins. Further, as the wax used in the toner of the present invention, an ester-based or olefin-based wax is selected, and a wax having a melting point of 65 to 90 ° C., which is incompatible with the binder resin, is dispersed in the binder resin. In this case, the wax oozes out of the toner surface at the time of fixing and has sufficient offset resistance even in a state where oil is not applied to the fixing roller. Here, the wax is preferably immiscible with the binder resin. If the wax is compatible with the binder resin, the effect of exuding the wax at the time of fixing is lost, and offset tends to occur. Also,
The melting point of the wax is preferably in the above range. If the melting point is lower than the above range, blocking during storage of the toner is likely to occur, and offset may easily occur. Conversely, if the temperature is higher than the above range, offset may easily occur in a region where the fixing roller temperature is low.

The softening point of the binder resin was measured as follows. Using an elevated flow tester (CFT-500, manufactured by Shimadzu Corporation), the diameter of the pores of the die was 1 mm, and the pressure was 20
kg / cm ² , 1 cm ³
The temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the sample is melted and discharged is defined as the softening point.

The molecular weight of the binder resin was measured as follows. <Molecular Weight Measurement by GPC> The column was stabilized in a constant temperature bath at 40 ° C., THF (tetrahydrofuran) was flowed as a melt at a flow rate of 1 ml / min, and the sample concentration was adjusted to 0.0
The THF solution of the sample adjusted to 5 to 0.5% by weight was 200
Measure by injecting μl. The molecular weight of the sample was calculated from the molecular weight distribution determined from the retention time based on a calibration curve created in advance. The calibration curve at this time was prepared using several types of monodisperse polystyrene as a standard sample (analytical column: Excel pak SEC-G1).
4 / G16 / G18 (Yokogawa Analytical Systems Co., Ltd.). The average dispersed particle diameter of the wax in the binder resin is preferably 0.3 to 3 μm. If the average particle diameter is smaller than this, offset may occur at the time of fixing. In addition, phenomena such as deterioration of transparency and occurrence of blocking during storage of the toner are likely to occur.

The melting point of the wax was measured as follows. That is, Rigaku THERM made by Rigaku Denki
With the OFLEX TG8110 type, the heating rate was 10 ° C /
The measurement is performed under the condition of min, and the main maximum peak of the endothermic curve is defined as the melting point.

The average dispersed particle diameter of the binder resin of the wax was measured as follows. Using a transmission electron microscope, the sample after the melt-kneading of the toner was measured for 50 wax dispersion particle diameters (the average value of the long axis and the short axis is a dispersion particle diameter) in a visual field at a magnification of 100,000 times, The average value was defined as the average dispersed particle size. Further, as the binder resin, a polyester resin and / or a polyol resin are particularly preferable, and as the binder resin used in the present invention, the following are particularly preferable. 《Polyester resin》

[0023]

Embedded image (Wherein, R ¹ is an alkylene group having 2 to 4 carbon atoms,
x and y are positive integers, and the average value of the sum is 2 to 16. )

[0024]

Embedded image

[0025]

Embedded image (In the formula, R ² and R ³ are a saturated or unsaturated hydrocarbon group having 4 to 20 carbon atoms.) A diol component represented by the general formula (I) and (b) a divalent or higher polyvalent carboxylic acid An acid component containing a dicarboxylic acid or an anhydride thereof represented by the general formula (II) or (III) selected from the group consisting of an acid, an anhydride thereof and a lower alkyl ester thereof, It is a polyester resin obtained by condensation polymerization of melitic acid or an acid component containing an anhydride thereof. Compounds such as phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, anhydrides thereof, and lower alkyl esters thereof can be used as the remaining components of (b). Examples of the compound represented by the general formula (II) or (III) include n-dodecenylsuccinic acid, n-dodecylsuccinic acid, n-butylsuccinic acid, iso-dodecenylsuccinic acid,
Examples thereof include succinic acid derivatives such as iso-octyl succinic acid. In particular, the toner has sufficient fixability at low temperatures as a toner and further improves gloss.

Examples of the diol represented by the general formula (I) include polyoxypropylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyester (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6)-
Examples thereof include 2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (16) -2,2-bis (4-hydroxyphenyl) propane.

It is to be noted that a bifunctional or higher polyhydroxy compound as described below may be used in the diol component in an amount of about 5 mol% or less. Ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or etherified polyhydroxyl compounds thereof. The polyester resin is usually prepared by mixing a polyol component and a polycarboxylic acid component in an inert gas atmosphere at 180 to 2 times.
It can be produced by condensation polymerization at a temperature of 50 ° C.

As the polyol resin, various types can be used.
The following are particularly preferred. Particularly as a polyol resin, an epoxy resin, an alkylene oxide adduct of dihydric phenol or glycidyl ether thereof,
It is preferable to use a polyol obtained by reacting a compound having one active hydrogen that reacts with an epoxy group in a molecule and a compound having two or more active hydrogens that react with an epoxy group in a molecule. Furthermore, the epoxy resin of
Particularly preferred are at least two or more bisphenol A type epoxy resins having different number average molecular weights. This polyol resin gives good gloss and transparency, and is effective in offset resistance.

The epoxy resin used in the present invention is preferably obtained by bonding a bisphenol such as bisphenol A or bisphenol F with epichlorohydrin. Epoxy resin is a bisphenol A type epoxy resin having at least two kinds of bisphenol A type epoxy resins having different number average molecular weights in order to obtain stable fixing characteristics and gloss, the number average molecular weight of the low molecular weight component is 360 to 2000, and the high molecular weight component is It is preferable that the number average molecular weight is 3,000 to 10,000. Further, it is preferable that the low molecular weight component is 20 to 50 wt% and the high molecular weight component is 5 to 40 wt%. When there are too many low molecular weight components, or when the molecular weight is lower than 360, glossiness may be too high and storage stability may be deteriorated. When the amount of the high molecular weight component is too large, or when the molecular weight is higher than 10,000, the gloss may be insufficient or the fixability may be deteriorated.

As the compound used in the present invention,
Examples of the alkylene oxide adduct of a dihydric phenol include the following. Examples include ethylene oxide, propylene oxide, butylene oxide, and a reaction product of a mixture thereof with a bisphenol such as bisphenol A or bisphenol F. The obtained adduct may be glycidylated with epichlorohydrin or β-methylepichlorohydrin before use. In particular, the following general formula (VI)
The diglycidyl ether of an alkylene oxide adduct of bisphenol A represented by

[0031]

Embedded image Further, n and m are the numbers of repeating units, each being 1 or more, and n + m = 2 to 6. )

It is preferable that the alkylene oxide adduct of dihydric phenol or its glycidyl ether is contained in an amount of 10 to 40% by weight based on the polyol resin. Here, if the amount is small, a problem such as an increase in curl occurs, and if n + m is 7 or more or the amount is too large, there is a possibility that gloss is excessively obtained or storage stability is deteriorated. Examples of the compound having one active hydrogen that reacts with the epoxy group in the molecule used in the present invention include monohydric phenols, secondary amines, and carboxylic acids. The following are illustrated as monohydric phenols. That is, phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol and the like can be mentioned. Secondary amines include diethylamine, dipropylamine, dibutylamine, N-methyl (ethyl) piperazine, piperidine and the like. Examples of the carboxylic acids include propionic acid and caproic acid.

In order to obtain a polyol resin having an epoxy resin part and an alkylene oxide part in the main chain of the present invention, various raw material combinations are possible. For example,
Dihalide or diisocyanate, diamine, dithiol, epoxy resin of both terminal glycidyl group and alkylene oxide adduct of dihydric phenol of both terminal glycidyl group,
It can be obtained by reacting with a polyhydric phenol or dicarboxylic acid. Of these, the reaction with dihydric phenol is most preferable in terms of reaction stability. It is also preferable to use a polyhydric phenol or a polycarboxylic acid together with a dihydric phenol within a range not causing gelation. Here, the amount of the polyhydric phenols and polycarboxylic acids is 15 to the total amount.
% Or less, preferably 10% or less.

The compound used in the present invention having two or more active hydrogens which react with an epoxy group in the molecule includes 2
And polyhydric phenols, polyhydric phenols, and polyhydric carboxylic acids. Examples of the dihydric phenol include bisphenols such as bisphenol A and bisphenol F. As polyhydric phenols, ortho-cresol novolaks, phenol novolaks, and tris (4-
(Hydroxyphenyl) methane, 1- [α-methyl-α-
(4-hydroxyphenyl) ethyl] benzene. Examples of polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid,
Examples include phthalic acid, terephthalic acid, trimellitic acid, and trimetic anhydride. When these polyester resins and polyol resins have a high crosslink density, it is difficult to obtain transparency and glossiness. Preferably, the crosslinkage is not crosslinked or weakly crosslinked (THF insoluble content is 5% or less). preferable.

Further, it has been clarified that particularly when the wax incompatible with the binder resin is an ester or olefin wax, the offset resistance is particularly improved. Since these waxes are incompatible with the binder resin and are dispersed uniformly, they exhibit offset resistance at the time of fixing the toner. Particularly, when the polyol resin or the polyol resin is used as the binder resin, the effect is improved. high. In addition,
Here, the ester wax refers to a wax having an ester bond, and natural waxes such as candelilla wax, carnauba wax, and rice wax;
And montan wax, and the olefin-based wax includes polyethylene wax, polypropylene wax and the like.

Next, other materials used in the present invention will be described. First, as the binder resin, the following can be added in addition to the binder resins A and B having the characteristics of the present invention. Polystyrene, poly-p-chlorostyrene, homopolymers of styrene such as polyvinyltoluene and substituted products thereof; styrene-p-chlorostyrene copolymer,
Styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer,
Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate Copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-
Styrene-based copolymers such as indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester , Polyurethane,
Polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, etc.

Next, as the coloring agent, dyes and pigments capable of obtaining yellow, magenta, cyan and black toners can be used. For example, carbon black, lamp black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6G, lake, chaco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, etc. Any conventionally known dyes and pigments, such as the dyes and pigments described above, can be used alone or in combination. The amount of these coloring agents to be used is generally 1 to 30% by weight, preferably 3 to 20% by weight, based on the binder resin.

It is preferable to use a charge control agent for imparting charge to the toner and to obtain a stable charge amount.
As the charge control agent in this case, it is preferable to add a transparent to white substance that does not impair the color tone of the color toner and stabilize and impart the toner to negative or positive polarity. Specifically, quaternary ammonium salts, imidazole metal complexes and salts, etc. are used as the positive polarity, and salicylic acid metal complexes and salts as the negative polarity,
Organic boron salts, calixarene-based compounds and the like are used.

The particle diameter of the toner of the present invention is preferably about 3 to 10 μm in terms of volume average particle diameter. If the particle diameter is smaller than this, it may cause background contamination during development and may deteriorate fluidity. In some cases, toner replenishment and cleaning properties may be impaired. Further, when the particle diameter is larger than this, dust in an image, deterioration of resolution, and the like may cause a problem.

For the purpose of improving the fluidity of the toner, hydrophobic silica, titanium oxide, alumina or the like can be added as an external additive. In addition, fatty acid metal salts (such as zinc stearate and aluminum stearate) and polyvinylidene fluoride may be added as necessary.

[0041]

The present invention will be described below in more detail with reference to examples. However, the present invention is not limited to these. In addition, the characteristic measurement was performed as follows. <Temperature range where no offset occurs> Using a Ricoh color copier Pretail 550, copy paper (Ricoh type 60
00-70 W), a solid image composed of a single color of yellow, magenta, cyan, and black, and red, blue, and green as intermediate colors is added to a single color of 1.0 ± 0.1 (mg).
/ Cm ² ), and the temperature at which no offset occurs was measured by adjusting the temperature of the fixing roller to be variable. The evaluation was performed under the condition that oil was not applied to the fixing roller.

<Glossiness> In the above monochrome image sample, the glossiness of the sample when the fixing roller surface temperature was 160 ° C. was measured by a gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. at an incident angle of 60 °. As for the gloss, the higher the value, the more the glossiness appears. As a full-color copy image, moderate gloss is preferred, and about 10 to 30% is preferred.

<Haze Degree> The above single-color image sample was prepared by using a Ricoh type PPC-DX as a transfer paper, and the haze degree of the sample when the surface temperature of the fixing roller was 160 ° C. was directly read by a haze computer manufactured by Suga Test Instruments Co., Ltd. HGM
It was measured by a type-2DP. The haze is also referred to as the haze and is measured as a measure of the transparency of the toner. The lower the value, the higher the transparency, and the better the color developability when using OHP paper. Further, the value of the haze indicating good color developability is preferably 30% or less.

Example 1 Binder Resin A (Polyester resin: polyester resin synthesized from ethylene oxide adduct of bisphenol A, terephthalic acid, fumaric acid, Mw: 35000, Mn: 12000, Mw / Mn: 2. 9, softening point 92 ° C) ... 70 parts by weight Binder resin B (styrene-acrylic resin: resin synthesized from polystyrene and butyl acrylate, Mw: 75000, Mn: 12000, Mw / Mn: 6.3, softening 30 parts by weight wax (micro wax: melting point 81 ° C.) 4 parts by weight colorant <for yellow toner> Disazo yellow pigment (CI Pigment Yellow 17) 5 Parts by weight <for magenta toner> Quinacridone-based magenta pigment (CI Pigment Red 122) 4 parts by weight (for cyan toner) Copper phthalocyanine blue pigment (CI Pigment Blue 15) 2 parts by weight <for black toner> Carbon black 6 parts by weight Charge control agent (salicylic acid) Derivative zinc salt) ... 2 parts by weight

After the above materials were sufficiently mixed by a blender for each color, they were melted and kneaded by two rolls heated to 100 to 110 ° C. After allowing the kneaded material to cool naturally, coarsely pulverize it with a cutter mill, pulverize it with a fine pulverizer using a jet stream,
Base colored particles of each color were obtained using an air classifier. In addition, the volume average particle diameter of each color base colorant particle was as follows. (The volume average particle size was measured by a Coal Counter Model TA-II manufactured by Coulter Electronics Co., Ltd.) Yellow: 7.6 μm Magenta: 7.4 μm Cyan: 7.7 μm Black: 7.8 μm

Further, 0.5 parts by weight of hydrophobic silica was mixed with 100 parts by weight of the base colored particles using a Henschel mixer to obtain toners of yellow, magenta, cyan and black. This toner is mixed with a tumbler mixer at a ratio of 5 parts by weight to 100 parts by weight of a carrier obtained by coating a silicone resin on ferrite particles having an average particle diameter of 50 μm and mixed with yellow, magenta, cyan, and black. A developer was obtained.

The obtained developer was used with Ricoh Pretail 5
The image was taken out without setting oil in the fixing device. As a result, a clear full-color image was obtained, the fixability and gloss were good, the offset margin was high, and the color developability using OHP paper was also good. A summary of the examples is shown in Table 1.

Example 2 Binder Resin A (Polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A, terephthalic acid, succinic acid dielectric, Mw: 400000, Mn: 13000, Mw / Mn: 3.1, softening point 94 ° C) ... 40 parts by weight Binder resin B (polyester resin: synthesized from propylene oxide and ethylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative, trimellitic anhydride) Polyester resin, Mw: 80000, Mn: 13000, Mw / Mn: 6.2, softening point 115 ° C) 60 parts by weight wax (paraffin wax: melting point 71 ° C) 5 parts by weight colorant and Charge control agent: same as in Example 1

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.2 μm Magenta: 7.9 μm Cyan: 7.6 μm Black: 7.8 μm Further, the same processing as in Example 1 was performed to obtain a toner of each color and a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Example 3 Binder Resin A (Polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A, fumaric acid, succinic acid dielectric, Mw: 30000, Mn: 10000, Mw / Mn: 3 0.0, softening point 96 ° C) ... 50 parts by weight Binder resin B (polyol resin: low molecular weight bisphenol A type epoxy resin, high molecular weight bisphenol A type epoxy resin, glycidylated product of bisphenol A type ethylene oxide adduct, Polyol resin synthesized from bisphenol F and p-cumylphenol, Mw: 62000, Mn: 9000, Mw / Mn: 6.9, softening point 120 ° C) 50 parts by weight wax (ester wax: melting point 83) ° C) ... 6 parts by weight colorant and charge control agent ... same as in Example 1

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.4 μm Magenta: 7.5 μm Cyan: 7.8 μm Black: 7.6 μm Further, the same processing as in Example 1 was performed to obtain a toner of each color and a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Example 4 Binder Resin A (Polyol resin: low molecular weight bisphenol A type epoxy resin, high molecular weight bisphenol type epoxy resin, glycidylated product of bisphenol A type ethylene oxide adduct, bisphenol F, p-cumylphenol Polyol resin synthesized from Mw: 30,000, Mn: 12,000, Mw / Mn: 2.5, softening point: 95 ° C) ... 50 parts by weight Binder resin B (Polyester resin: propylene oxide adduct of bisphenol A) , Fumaric acid, polyester resin synthesized from dielectric material of succinic acid, Mw: 88000, Mn: 11,000, Mw / Mn: 8.0, softening point: 122 ° C) 50 parts by weight wax (ester-based wax: melting point) 83 ° C.) 5 parts by weight colorant and charge control agent Same as Example 1.

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.1 μm Magenta: 7.6 μm Cyan: 7.9 μm Black: 7.4 μm Further, the same processing as in Example 1 was performed to obtain a toner of each color and a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Example 5 Binder Resin A (Polyol Resin: Same Composition as Used in Binder Resin B of Example 3, Mw: 45000, Mn: 15000, Mw / Mn: 3.0, Softening Point: 98) 70 ° C.) Binder resin B (polyester resin: the same composition as that used for binder resin A in Example 3, Mw: 92000, Mn: 11000, Mw / Mn: 8.4, softening point 120 ° C.) 30 parts by weight wax (polyethylene wax: melting point 80 ° C.) 5 parts by weight colorant and charge control agent Same as in Example 1.

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.5 μm Magenta: 7.2 μm Cyan: 7.8 μm Black: 7.4 μm Further, the same processing as in Example 1 was performed to obtain a toner of each color and a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Example 6 Binder Resin A (Polyester Resin: Same Sample as Used in Binder Resin A of Example 3) 50 parts by weight Binder Resin B (Polyol Resin: Binder of Example 3) The same composition as that used for the resin B, Mw: 28000, Mn: 7800, Mw / Mn: 3.6, softening point 133 ° C) 50 parts by weight wax (ester-based wax: melting point 83 ° C) ..5 parts by weight of colorant and charge control agent: same as in Example 1

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.3 μm Magenta: 7.6 μm Cyan: 7.4 μm Black: 7.2 μm Further, the same processing as in Example 1 was performed to obtain toners of each color and further a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Comparative Example 1 Binder Resin A (Polyol resin: the same composition as that used for binder resin B of Example 3, Mw: 5000, Mn: 10,000, Mw / Mn: 5.0, softening point 100) 100 ° C.) 100 parts by weight wax (paraffin wax: melting point 70 ° C.) 5 parts by weight colorant and charge control agent Same as in Example 1.

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.2 μm Magenta: 7.8 μm Cyan: 7.9 μm Black: 7.4 μm Further, the same processing as in Example 1 was performed to obtain toners of each color and further a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

Comparative Example 2Binder resin A (Polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A, terephthalic acid, succinic acid dielectric, Mw: 800000, Mn: 40000, Mw / Mn: 2.0, softening point 105 ° C) ..70 parts by weightBinder resin B (Polyol resin: the same composition as used for binder resin B in Example 3, Mw: 92,000, Mn: 11000, Mw / Mn: 8.4, softening point: 120 ° C) ... 30 parts by weightwax  (Polypropylene wax: melting point 130 ° C) ··· 5 parts by weightColorant and charge control agent ... Same as Example 1

The above materials were treated in the same manner as in Example 1 to obtain a toner having the following volume average particle diameter. Yellow: 7.6 μm Magenta: 7.5 μm Cyan: 7.7 μm Black: 7.3 μm Further, the same processing as in Example 1 was performed to obtain a toner of each color and a developer. Next, the same evaluation as in Example 1 was performed using the obtained developer. Table 1 shows the results of the evaluation.

[0062]

[Table 1-1]

[0063]

[Table 1-2]

[0064]

[Table 1-3]

[0065]

As is apparent from the above detailed and specific description, the electrophotographic color toner of the present invention is a color toner comprising at least two kinds of binder resins, coloring agents and waxes. The binder resin has a weight average molecular weight (Mw) of 10,000 to 50,000, a ratio (Mw / Mn) to a number average molecular weight (Mn) of 2 to 5, and a softening point of 90 to 100 ° C. , Mw is 20,000 to 100,000,
And Mw / Mn is 3.5-10, and softening point is 105-
Since the toner is a color toner containing a binder resin at 135 ° C., oil is not applied to the fixing roller,
(1) It shows good fixability, (2) high gloss and transparency, (3) high temperature offset is sufficiently prevented, and
When the binder resins A and B are made of any one of the polyester resin and the polyol resin, the fixing property,
Glossiness, transparency is further improved, furthermore, the wax is incompatible with the resin, ester-based, olefin-based melting point of 65 to 90 ℃, it is difficult to generate high-temperature offset, Furthermore, when the average dispersed particle size of the wax in the binder resin is from 0.3 to 3 μm, an extremely excellent effect of further improving the transparency is exhibited.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuteru Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Tomomi Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Inside the company Ricoh

Claims (4)

[Claims] 1. A color toner comprising at least two kinds of binder resins, a colorant and a wax, wherein the two kinds of binder resins have a weight average molecular weight (Mw) of 10,000 to 500.
00, and the ratio to the number average molecular weight (Mn) (Mw / Mn)
A having a softening point of 2 to 5 and a softening point of 90 to 100 ° C
And Mw is 20,000 to 100,000 and Mw / Mn is 3.5 to 1
An electrophotographic color toner comprising a binder resin B having a softening point of 0 to 105 ° C. to 135 ° C. 2. The color toner according to claim 1, wherein the binder resins A and B are made of any one of a polyester resin and a polyol resin. 3. The wax is incompatible with a binder resin, is an ester or an olefin, and has a melting point of 65 to 9.
2. The color toner for electrophotography according to claim 1, wherein the temperature is 0C. 4. An average dispersion particle diameter of the wax in the binder resin is 0.3 to 3 μm.
2. The color toner for electrophotography according to 1.