JPH10207126A - Electrophotographic color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a full-color toner having satisfactory fixability without coating a fixing roll with oil, having high glossiness and transparency and capable of satisfactorily preventing offsetting at high temp. by using a specified wt. or more of binder resin, in which the ratio of the weight average mol.wt. to a number average mol.wt. is a specified range and having the weight average mol.wt. of the specified range. SOLUTION: This color toner consists essentially of a binder resin, a colorant and wax. The binder resin contains >=70wt.% binder resin having a weight average mol.wt. (Mw) of 15,000-70,000. The ratio (Mw/Mn) of the weight average mol.wt. (Mw) to the number average mol.wt. (Mn) is 15-30. In the case of Mw/Mn<15, offsetting is liable to occur. In the case of Mw/Mn>30, satisfactory glossiness and transparency may not be ensured. When the Mw is <15,000, it is difficult to ensure satisfactory anti-offsetting property. When the Mw is >70,000, satisfactory glossiness and transparency may not be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel color toner, and more particularly to an excellent color toner 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 is 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 a document 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 electrophotographic method in which 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 characteristics that the color toner should have are 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 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.

In general, the reason why oil is applied to fix a color toner is as follows. That is, in general, the color toner needs to have higher heat melting property, lower viscosity, and gloss or transparency than black toner for black and white printing at the time of fixing and heating. However, in a toner using such a resin, the intermolecular cohesion at the time of heat melting is apt to decrease, so that the toner adheres to the heat roller when passing through the fixing roller, and a high-temperature offset phenomenon occurs. 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 addition, in the case of a highly viscous toner, such as a black toner for black and white printing, since the intermolecular cohesive force at the time of thermal melting of the toner is high, offset can be prevented by exuding a small amount of wax. The toner is not melted, and the gloss and transparency are insufficient. For the above reasons, 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 at present.

Japanese Patent Publication No. Hei 8-12475 discloses an etherified diphenol component, a hydrocarbon group-substituted divalent carboxylic acid or a derivative thereof, a trivalent or higher polycarboxylic acid and / or a polyol, or a derivative thereof. Consisting of components,
A color toner using a polyester resin having a limited apparent viscosity and DSC endothermic peak is described.
JP-A-1-144625 discloses a magenta toner in which a certain pigment is added to a resin mixture of a polyester resin having a softening point of 80 to 150 ° C. and a solid silicone varnish having a molecular weight of 500 to 2,000.
The gazette describes a toner having a haze value of 7 to 30% in a dispersion of a binder resin. The binder resin uses a weakly cross-linked resin, and is oil-less and has offset resistance. Not enough.

[0006] Japanese Patent Application Laid-Open No. Hei 5-158282 discloses that there are two compounds selected from isophthalic acid, terephthalic acid and derivatives thereof.
Divalent aromatic acid component (a), trivalent aromatic acid component (b) selected from trimellitic acid and derivatives thereof, and divalent aromatic acid component selected from dodecenyl succinic acid, octyl succinic acid and anhydride thereof It is formed from the acid component (c), propoxylated and / or ethoxylated etherified diphenol (d) and has a hydroxyl value of 10 to 20, Mw: 13000 to 2000.
0, Mn: 5000-8000, Mw / Mn = 2-3.
5 discloses a color toner containing a polyester resin and a method for forming a color image. However, this technique is oil-less, has insufficient offset resistance, and is disclosed in
Japanese Patent No. 19274 discloses that a water-containing paste of a polyolefin wax and a pigment is mixed into a pigment dispersing resin solution and then heated, and the difference between SP values of the binder resin and the pigment dispersing resin is 1 Japanese Patent Application Laid-Open No. 7-31479 discloses a color roller having a fixing roller using a toner disclosed in Japanese Patent Application Laid-Open No. The use of layers is disclosed. However, the color toners in these techniques aim at high dispersion of the polyolefin wax in the binder resin, but it is not sufficient to expect only the effect of the polyolefin wax in order to impart oillessness.

Japanese Patent Application No. 7-333903 discloses a toner containing a polyester resin containing no THF (tetrahydrofuran) insoluble matter having Mn of 2500 to 3500 and Mw of 50,000 to 300,000. It is necessary to apply a very small amount of oil, and the oil-less operation is insufficient. Japanese Patent Application Laid-Open No. 7-333904 discloses wax and T
A polyester resin having an HF-insoluble content of 15 to 40% and a polyhydric alcohol component limited is used, and the difference in the refractive index between the binder resin and the wax is limited, but this toner contains a large amount of the THF-insoluble component. , It is difficult to obtain high gloss.

Japanese Patent Application Laid-Open No. 8-503367 discloses that in a wax-containing toner, the molecular weight of the wax is from 350 to 85.
0 and a maximum value in each range of 900 to 4000, and M
JP-A-8-800 describes an ester wax-containing toner having a w: 350-4000 and Mn: 200-4000.
Japanese Patent No. 50368 discloses a wax-containing toner in which an ester compound having the same total number of carbon atoms is contained in an ester wax at 50 to 95% by weight, but sufficient oillessness can be obtained only by limiting the properties of the wax. I can't.

[0009] Japanese Patent Application Laid-Open No. 3-39971 discloses that no toluene-insoluble matter is contained and the molecular weight is 500-2000 and 1
It has a peak in the range of 10,000 to 100,000, Mw: 10,000 to 80,000,
A resin-containing color toner having Mn: 1500 to 8000 and Mw / Mn> 3 is disclosed in JP-A-4-5706.
No. 2 discloses a flow tester having a melt viscosity of 10 ⁵ poise, a softening temperature of 90 to 120 ° C., and a Mw of 1.5 × 10 ^{4 to} 5 ×.
10 ⁴ , Mn is 2 × 10 ³ to 1 × 10 ⁴ , and Mw / Mn =
Although 5 to 15 resin-containing color toners are disclosed,
The oil-less operation by these toners is not yet sufficient.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems in the prior art, and to show good fixability without applying oil to a fixing roller in a full-color toner, to achieve glossiness and transparency. An object of the present invention is to provide a full-color toner which has high performance and can sufficiently prevent offset at high temperatures.

[0011]

Means for Solving the Problems The problems as described above are:
(1) “In a color toner comprising at least a binder resin, a colorant, and a wax, a ratio (Mw) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the binder resin
/ Mn) is 15-30, and Mw is 15,000-
A color toner comprising 70% by weight or more of the binder resin (A) in the range of 70000. ”, (2)
"The color toner according to item (1), wherein the binder resin (A) has a softening point of 90 to 120 [deg.] C.", (3) "average dispersed particles of the wax in the toner." The color toner according to item (1), wherein the diameter is from 0.2 to 3 μm. ”And (4)“ the wax is an ester-based or olefin-based wax. (1) The color toner described in (1)).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a pressure fixing system using a heat fixing roller for obtaining a color image in an electrophotographic system, the present inventors have studied and found that a color toner having the structure of the present invention is used. Accordingly, sufficient offset resistance can be obtained without applying oil to the fixing roller. Hereinafter, the contents of the present invention will be described in detail and concretely. That is, in the color toner composed of the binder resin, the colorant, and the wax, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the binder resin is 15 to 30, and Mw is 15000
By containing 70% by weight or more of the binder resin (A) of up to 70,000, the viscosity of the toner is reduced at the time of fixing, and sufficient melting occurs, so that gloss and transparency can be obtained. A decrease in force is less likely to occur, and an offset is less likely to occur.

When Mw / Mn is smaller than 15,
Offset may easily occur, and when it is larger than 30, gloss and transparency may be insufficient. If Mw is less than 15,000, it may be difficult to obtain sufficient offset resistance, and 70
When it is larger than 000, gloss and transparency may be insufficient. Further, the softening point of the binder resin (A) is particularly preferably from 90 to 120 ° C. If the softening point is lower than 90 ° C, offset tends to occur, and blocking tends to occur during storage of the toner. . Conversely 1
If the temperature is higher than 20 ° C., the gloss and the transparency may be insufficient.

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 was flowed at a flow rate of 1 ml / min as an eluent, and a THF solution of a sample adjusted to a sample concentration of 0.05 to 0.5% by weight was used. Inject 200 μl and measure.
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 standard samples. Analysis column: Excel pak SEC-G14 / G
16 / G18 (Yokogawa Analytical Systems Co., Ltd.)
Made)

The softening point of the binder resin was measured as follows. That is, an elevated flow tester (CFT-50)
0) (manufactured by Shimadzu Corporation), 1 m diameter of the pores of the die
m, a temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when a 1 cm ³ sample is melted and discharged under the conditions of a pressure of 20 kg / cm ² and a heating rate of 6 ° C./min. Point. In particular, the wax used in the present color toner has an average dispersed particle size in the toner of 0.2 to 3 μm, so that the wax exudes to the toner surface during fixing and the oil is applied to the fixing roller. It has sufficient offset resistance even in a state where it is not used. If the average dispersed particle diameter of the wax in the toner is smaller than 0.2 μm, a sufficient effect of exuding the wax at the time of fixing may be weak, and sufficient offset resistance may not be obtained. If it is larger than 3 μm, the chargeability may be deteriorated due to a decrease in the fluidity of the toner or contamination on the carrier surface due to detachment from the toner surface. The average dispersed particle diameter of the wax in the toner can be confirmed by a transmission electron microscope. This definition in the present invention is obtained by averaging 100 points of a randomly selected wax portion from an enlarged photograph at a magnification of 100,000. Things. Further, the melting point of the wax is particularly preferably from 65 to 90 ° C. If the temperature is lower than this range, blocking tends to occur during storage of the toner, and the offset may easily occur. On the other hand, if the temperature is high, the offset tends to occur in a region where the temperature of the fixing roller is low. There is.

The melting point of the wax was measured as follows. Rigaku THE melting point analyzer (Rigaku THE)
RMOFLEX TG8110 type)
It is measured under the condition of ° C./min, and the main peak of the endothermic curve is defined as the melting point. Further, in the present invention, it has been clarified that particularly when the wax used is an ester-based or olefin-based wax, the offset resistance is particularly improved. Since these waxes are uniformly dispersed as incompatible with the binder resin, they exhibit offset resistance at the time of fixing the toner, and the effect is particularly high when a polyester resin or a polyol resin is used as the binder resin. . Here, the ester-based wax means a wax having an ester bond, and includes natural waxes such as candelilla wax, carnauba wax, rice wax, and montan wax, and the olefin-based wax includes polyethylene wax. And polypropylene wax.

Next, the specific contents of the materials used for the color toner of the present invention will be described. The composition of the binder resin (A) used in the present invention is particularly one of a polyester resin and a polyol resin, and is particularly excellent in gloss, transparency, and offset resistance. As the polyester resin, various types can be used, but the following are particularly preferable as the polyester resin used in the present invention.
I. The following general formula (I)

[0018]

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. A) a diol component; It is a polyester resin obtained by condensation-polymerizing a component selected from the group consisting of a divalent or higher polyvalent carboxylic acid, an anhydride thereof and a lower alkyl ester thereof.

B. Specific examples of phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid and their anhydrides, and lower alkyl esters thereof,
Acid containing trimellitic acid or its anhydride, n-
And succinic acid derivatives such as dodecenylsuccinic acid, n-dodecylsuccinic acid, n-butylsuccinic acid, iso-dodecenylsuccinic acid and iso-octylsuccinic acid. By introducing these succinic acid derivatives, the fixability of the toner at a low temperature becomes sufficient, and the gloss is further improved.

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 should be noted that a bifunctional or higher polyhydroxy compound as described below may be used as 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 can be usually produced by polycondensing a polyol component and a polycarboxylic acid component at a temperature of 180 to 250 ° C. in an inert gas atmosphere.

As the polyol resin, various types can be used. In the present invention, particularly, as the polyol resin, an epoxy resin, an alkylene oxide adduct of dihydric phenol or its glycidyl ether, It is preferable to use a polyol obtained by reacting a compound having one active hydrogen in a molecule that reacts with a compound with a compound having two or more active hydrogens in a molecule that reacts with an epoxy resin group. Furthermore,
The epoxy resin is particularly preferably at least two or more bisphenol A epoxy resins having different number average molecular weights. In this case, the polyol resin gives good gloss and transparency, and is effective in offset resistance.
The epoxy resin used in the present invention is preferably one obtained by combining bisphenol such as bisphenol A or bisphenol F with epichlorohydrin.

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

[0023]

Embedded image (Wherein, R _{-CH 2 -CH 2 -, - CH} 2 -CH (CH 3)
— Or —CH ₂ —CH ₂ —CH ₂ — groups, and n, m
Is the number of repeating units, each is 1 or more, and n +
m = 2-6. In addition, it is preferable that an alkylene oxide adduct of dihydric phenol or glycidyl ether is contained in an amount of 10 to 40% by weight based on the polyol resin. If the amount is small, problems such as an increase in curl may occur, and if n + m is 7 or more, or if the amount is too large, gloss may be too high, and furthermore, storage stability may be deteriorated.

The compound having one active hydrogen which reacts with the epoxy group in the molecule used in the present invention includes 1
There are polyhydric phenols, secondary amines and carboxylic acids.
Examples of the monohydric phenols include the following.
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. Also,
Examples of the carboxylic acids include propionic acid and caproic acid.

In the present invention, the compound having one active hydrogen which reacts with the epoxy group in the molecule may be a compound having the alkylene oxide adduct of dihydric phenol, dihalide, diisocyanate, diamine, dithiol, polyhydric phenol or dicarboxylic acid. It can be obtained by reacting with an acid. Of these, the reaction with dihydric phenol is most preferable in terms of reaction stability. Also, polyhydric phenols and polycarboxylic acids as long as they do not gel,
It is also preferable to use it in combination with a dihydric phenol. Here, the amount of polyhydric phenols and polycarboxylic acids is 1 to the total amount.
It is at most 5%, preferably at most 10%.

The compound used in the present invention having two or more active hydrogens which react with an epoxy group in a 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. Examples of the polyhydric phenols include orthocresol novolaks, phenol novolaks, tris (4-hydroxyphenyl) methane, and 1- [α-methyl-α- (4-hydroxyphenyl) ethyl] benzene. Examples of the polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, trimetic acid, and trimellitic anhydride.

When these polyester resins and polyol resins have a high crosslinking density, it is difficult to obtain transparency and glossiness. Preferably, they are non-crosslinked or weakly crosslinked (THF insoluble content is 5% or less). Is preferred.

First, as the binder resin, in addition to the binder resins (A) and (A) having the characteristics of the present invention, the following resins can be used if necessary. polystyrene,
Homopolymers of styrene such as poly p-chlorostyrene and polyvinyltoluene and substituted products thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer Polymer, 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-chloromethacrylic acid Methyl 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-based copolymers such as polymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, and polyacetic acid Vinyl, poly Styrene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin.

Next, as the colorant, 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.
In this case, as the charge control agent, 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 a negative polarity or a positive polarity. Specifically, a quaternary ammonium salt, an imidazole metal complex or a salt is used as the positive polarity, and a salicylic acid metal complex or a salt, an organic boron salt, a calixarene-based compound or the like is used as the negative polarity. .
The particle diameter of the toner of the present invention is 3 to 1 as a volume average particle diameter.
It is preferably about 0 μm. If the particle diameter is smaller than this, it may cause background contamination during development, or may deteriorate the fluidity and impair the toner replenishment and cleaning properties. Further, when the particle diameter is larger than this, there may be a problem such as dust in an image and deterioration of resolution. Further, as an external additive, hydrophobic silica, titanium oxide, alumina or the like can be added for the purpose of improving the fluidity of the toner. If necessary, fatty acid metal salts (such as zinc stearate and aluminum stearate) and polyvinylidene fluoride may be added.

[0031]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. The characteristic measurement was performed as follows. (1) Non-offset temperature range Using a Ricoh color copier Pretail 550, yellow, Ricoh type 6000-70W
A solid image composed of magenta, cyan, black, and red, blue, and green as intermediate colors is adjusted so that a toner of 1.0 ± 0.1 (mg / cm ² ) is developed in a single color. Was adjusted so that the temperature was variable, and the temperature at which no offset occurred was measured. The evaluation was performed under the condition that oil was not applied to the fixing roller. Gloss In the above monochrome image sample, the gloss 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. Moderate gloss is preferred as a full-color copy image, and 10 to 3
About 0% is preferable. Haze degree Type P made by Ricoh using the above monochrome image sample as transfer paper
Using PC-DX, the haze degree of the sample when the fixing roller surface temperature was 160 ° C. was measured by a direct read haze computer HGM-2DP type manufactured by Suga Test Instruments Co., Ltd. The haze is also referred to as haze, and is measured as a measure of the transparency of the toner.
Good color developability when using P paper. Also,
The value of the haze indicating good color development is preferably 30% or less.

Example 1 80 parts by weight of binder resin A (polyester resin: polyester resin synthesized from ethylene oxide adduct of bisphenol A, terephthalic acid, fumaric acid Mw: 19000, Mn: 1200, Mw / Mn: 15. 8, softening point 88 ° C) Binder resin 20 parts by weight (polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative, trimellitic anhydride Mw: 52000, Mn: 7200, Mw / Mn: 7.2, softening point: 116 ° C) Wax 4 parts by weight (microwax: melting point: 80 ° C)

Colorant <for yellow toner> 5 parts by weight of disazo-based yellow pigment (CIPigment Yellow 17) <for magenta toner> 4 parts by weight of quinacridone-based magenta pigment (CIPigment Red 122) <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 for each color by a blender, they were melted and kneaded by two rolls heated to 100 to 110 ° C. After the kneaded product was allowed to cool naturally, it was coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then a base colored particle of each color was obtained using an air classifier.
In addition, the volume average particle size of each color base coloring particle was as follows. (The volume average particle size was measured using a Coulter Counter Model TA-II manufactured by Coulter Electronics Co., Ltd.) Yellow: 7.6 μm Magenta: 7.4 μm Cyan: 7.7 μm Black: 7.3 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 colors. The present toner has an average particle diameter of 50 μm.
5 parts by weight with respect to 100 parts by weight of a carrier obtained by coating the surface of a ferrite particle with a silicone resin on a ferrite particle, were mixed with a Turbula mixer to obtain yellow, magenta, cyan and black color developers. The obtained developer was set on a Pretail 550 manufactured by Ricoh Co., Ltd., and an image was produced without setting the oil in the fixing device. As a result, a clear full-color image was obtained, the fixability and the 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 80 parts by weight of binder resin A (polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative Mw: 53000, Mn: 3300, Mw / Mn: 16 1.1, softening point 113 ° C) Binder resin 20 parts by weight (Polyester resin: Polyester resin synthesized from propylene oxide adduct and ethylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative, trimellitic anhydride Mw: 12000, Mn: 5800, Mw / Mn: 2.1, softening point: 123 ° C.) 5 parts by weight of wax (paraffin wax: melting point: 71 ° C.) The colorant and the charge control agent are the 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: 8.0 μm Magenta: 8.1 μm Cyan: 7.8 μm Black: 7.9 μm Further processing was performed in the same manner as in Example 1 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.

Example 3 100 parts by weight of binder resin A (polyol resin: low molecular weight bisphenol A type epoxy resin, high molecular weight bisphenol A type epoxy resin, bisphenol A type glycidylated product of ethylene oxide adduct, bisphenol F, p-c Polyol resin synthesized from millphenol: Mw: 65000, Mn: 4200, Mw / Mn: 15.5, softening point: 118 ° C.) Wax: 6 parts by weight (ester wax: melting point: 83 ° C.) This is the same as the first embodiment. 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: 8.4 μm Magenta: 8.2 μm Cyan: 7.9 μm Black: 8.3 μm Further processing was performed in the same manner as in Example 1 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 100 parts by weight (polyol resin: same composition as used in Example 3 Mw: 58000, Mn: 3300, Mw / Mn: 17.6, softening point 114 ° C.) Wax 5 Parts by weight (ester-based wax: melting point: 83 ° C.) The colorant and the charge control agent are the 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: 7.3 μm Cyan: 7.1 μm Black: 7.0 μm Further processing was performed in the same manner as in Example 1 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 80 parts by weight (polyester resin: the same composition as used in Example 3 Mw: 66000, Mn: 3000, Mw / Mn: 22, softening point 117 ° C.) Resin 20 parts by weight (Polyester resin: polyester resin synthesized from propylene oxide adduct of bisphenol A and ethylene oxide adduct, terephthalic acid, fumaric acid, trimellitic anhydride Mw: 14000, Mn: 5100, Mw / Mn: 2 0.7, softening point 94 ° C) Wax 5 parts by weight (polyethylene wax: melting point 80 ° C) The colorant and the charge control agent are the 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: 7.5 μm Cyan: 7.4 μm Black: 7.6 μm Further processing was performed in the same manner as in Example 1 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.

Comparative Example 1 100 parts by weight of binder resin A (polyol resin: having the same composition as that used in Example 3 Mw: 22000, Mn: 3600, Mw / Mn: 6.1, softening point: 100 ° C.) 5 parts by weight of wax (paraffin wax: melting point: 70 ° C.) The colorant and the charge control agent are the 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: 7.1 μm Magenta: 7.3 μm Cyan: 7.4 μm Black: 7.0 μm Further processing was performed in the same manner as in Example 1 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.

Comparative Example 2 Binder resin A 100 parts by weight (polyester resin: polyester resin synthesized from propylene oxide adduct and ethylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative, trimellitic anhydride Mw: 94000 , Mn: 5800, Mw / Mn: 16.2, softening point: 123 ° C.) 5 parts by weight of wax (polypropylene wax: melting point: 130 ° C.) The colorant and the charge control agent are the 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: 6.7 [mu] m Magenta: 6.5 [mu] m Cyan: 6.4 [mu] m Black: 6.8 [mu] m 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.

[0042]

[Table 1]

[0043]

As apparent from the detailed and specific description, the color toner of the present invention is a color toner comprising at least a binder resin, a colorant, and a wax.
Among the binder resins, a binder resin having a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 15 to 30, and Mw of 15,000 to 70,000
(A) is contained in an amount of 70% by weight or more.
Without applying oil to the fixing roller, a. Exhibits good fixability, b. High gloss and transparency, c. It is said that high-temperature offset is sufficiently prevented. And the softening point of the binder resin (A) is 90-
When the binder resin (A) has a softening point of 90 to 120 ° C. when the binder resin has a temperature of 120 ° C., better fixing properties, high gloss, transparency, and high-temperature offset can be prevented. Has an average dispersed particle size in the toner of 0.
When the average dispersed particle diameter of the wax in the toner is 0.2 to 3 μm,
Sufficient offset resistance is obtained. Further, when the wax is an ester-based or olefin-based wax, and further when the wax is an ester-based or olefin-based wax, a further excellent offset resistance can be obtained.

 ──────────────────────────────────────────────────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 a binder resin, a colorant, and a wax, wherein:
The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 15 to 30, and Mw is 150
A color toner comprising 70% by weight or more of the binder resin (A) in the range of from 00 to 70000. 2. The softening point of the binder resin (A) is 90 to 1
The color toner according to claim 1, wherein the temperature is 20C. 3. The color toner according to claim 1, wherein the average dispersed particle diameter of the wax in the toner is 0.2 to 3 μm. 4. The color toner according to claim 1, wherein the wax is an ester or olefin wax.