JP2002062689A - Electrostatic charge image developing color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magenta toner excellent in color reproducibility as well as in fixing property and offset resistance with which sharp image quality with colors extremely similar to natural colors can be obtained in the process of so-called multicolor printing using both a toner containing yellow pigments and a toner containing blue pigments. SOLUTION: The electrostatic charge image developing color toner consists of binder resin and organic pigments, and the binder resin is polyester resin having as the main structural components, (A) a polybasic acid compound selected from polybasic acids with two or more valences and/or acid anhydrides and/or lower alkyl esters of these, and (B) aliphatic polyhydric alcohol having two or more valences. The organic pigments are naphthol organic pigments expressed by chemical structural formula 1.

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 developing an electrostatic image for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art As a toner composition for obtaining a visible image by electrophotography, a toner composition in which a black colorant such as carbon black is dispersed in a binder resin is often used. However, recently, cyan pigments,
A color toner in which a magenta pigment, a yellow pigment, or another chromatic pigment is dispersed in a binder is also used, and a full-color or monocolor copying machine or printer using these color toners has been developed.

The characteristics required for such a color toner include that the image after printing has a vivid color developing property, and that excellent transparency is exhibited in the color superposition in multicolor printing. Having clear color reproducibility without color turbidity, or using an overhead projector (hereinafter, referred to as
It is required to have color reproduction characteristics such as the ability to project clear colors without turbidity when projecting a color image obtained by transferring and fixing on a sheet onto a screen.

Further, as a system for fixing a toner image, a heat roll fixing system is widely and generally used, and good fixing properties and offset resistance at that time are also important characteristics required for a color toner. is there. In recent color copiers and printers, the processing speed has been increased, and the fixing temperature is becoming lower and the fixing time is becoming shorter, and color toner is fixed with lower energy. In addition, it is required to have offset resistance.

[0005] In general, the composition of a color toner comprises a main component of a binder resin and a colorant, and various additives. As the binder resin, polystyrene, styrene- (meth) acrylate copolymer, styrene-butadiene copolymer, polyester, epoxy resin, coumarone indene resin and the like are generally used.

Conventionally, many techniques have been disclosed for such color toners. In particular, regarding a magenta or red color toner, Japanese Patent Application Laid-Open No. 51-24234 discloses a technique relating to a magenta toner using a quinacridone pigment. JP-A-59-165069 and JP-A-62-296167 disclose techniques relating to a magenta toner using various monoazo pigments.

However, these prior art magenta toners are not excellent in color reproducibility in a single color. In particular, improvement in coloring power and color reproducibility when color superimposition is performed with cyan and yellow color toners is required. ing. Furthermore, low-temperature fixing, or fixing properties at the time of low energy fixing such as short-time fixing,
Improvement in offset resistance is also required at the same time.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an excellent color reproducibility and a good and stable transfer image quality.
Another object of the present invention is to provide a magenta toner capable of obtaining a sharp image close to a natural color in so-called multi-color superposition using both a yellow pigment-containing toner and a blue pigment-containing toner.

Another object of the present invention is to provide a magenta toner which exhibits good fixing properties even under low energy fixing conditions such as low-temperature fixing or short-time fixing and has excellent offset resistance. .

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, the present invention is a color toner for developing an electrostatic image comprising a binder resin and an organic pigment,
The binder resin is mainly composed of (A) a polybasic acid compound selected from dibasic or higher polybasic acids and / or acid anhydrides and / or lower alkyl esters thereof; and (B) a dibasic or higher polyhydric aliphatic alcohol. The present invention provides a color toner for developing an electrostatic image, which is a polyester resin as a constituent component, wherein the organic pigment is a naphthol-based organic pigment having the following structure. Chemical structural formula 1

[0011]

Embedded image

Next, the present invention will be described in detail. The color toner for developing an electrostatic image of the present invention comprises a naphthol organic pigment having the above structure and a polyester resin obtained below.

The polybasic acid compound (A) selected from dibasic or higher polybasic acids and / or acid anhydrides and / or lower alkyl esters thereof used in the present invention includes, for example, phthalic anhydride, terephthalic acid , Isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, Glutaric acid, azelaic acid, a dicarboxylic acid such as sebacic acid or a derivative thereof or an esterified product thereof is also a trifunctional or higher polycarboxylic acid such as trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride. An acid or its derivative or its esterified product is mentioned.

Examples of the dihydric or higher aliphatic polyhydric alcohol (B) include, for example, 1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol,
Triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, hexanediol, polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer Diol, ethylene oxide-
Diols such as tetrahydrofuran copolymer diol, polycaprolactone diol, and sorbitol,
1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl -1,
Examples include trifunctional or higher polyhydric alcohols such as 2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trimethylolbenzene.

As the aliphatic alcohol component (B) which reacts with the carboxylic acid compound (A), neopentyl glycol diglycidyl ether, glycerin triglycidyl ether, trimethylol propane triglycidyl ether, trimethylol ethane tri Epoxy compounds such as glycidyl ether and pentaerythritol tetraglycidyl ether can also be used.

In the present invention, for example, an aromatic diol exemplified below can be used in combination with the aliphatic polyhydric alcohol. The aromatic diol that can be used in the present invention is polyoxyethylene- (2.0)
-2,2-bis (4-hydroxyphenyl) propane and its derivatives, polyoxypropylene- (2.0)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (6) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene-
(2.4) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxypropylene- (3.3) -2,2
-Bis (4-hydroxyphenyl) propane and its derivatives.

Further, aromatic epoxy compounds such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, cresol novolak type epoxy resin and phenol novolak type epoxy resin may be used as necessary. it can.

In the present invention, the flexibility of the molecular chain in the polyester resin is improved by using the aliphatic polyhydric alcohol, and when used as a two-component developer by mixing with the carrier, the stress applied to the carrier in the developing device is reduced. This has the effect of relaxing and preventing the resin coating layer on the carrier surface from peeling off, and as a result, has the effect of extending the life of the developer.

Further, the softness of the polyester main chain improves the fixability at low temperatures. Further, for the purpose of improving the fixing / offset performance, adding a wax to the toner is a commonly used means. In the polyester resin using the aliphatic polyhydric alcohol in the present invention, particularly, wax is used. Has good compatibility, and the fixing performance at low temperatures and the offset resistance are further improved.

Therefore, it is necessary to use the above aromatic diol within a range not to impair the gist of the present invention. The amount of the aromatic diol used is 30 to the total alcohol component.
Desirably, it is at most mol%. More preferably 20
Mol% or less.

As the carboxylic acid component used in the present invention, naphthalenedicarboxylic acid and / or dimethylnaphthalate, diethylnaphthalate, dibutylnaphthalate and the like as lower alkyl esters thereof are more preferably used. It is necessary that these compounds use 1 mol% or more of the total acid component, and more preferably 5 mol%.
That is all.

A monomer containing a naphthalene ring structure is effective in increasing the Tg of the resin, and improves the heat-resistant aggregation property of the resin. Particularly in a system mainly using a soft aliphatic diol as an alcohol component, a decrease in Tg of the resin can be suppressed, and a low-temperature fixability by using the aliphatic diol and a heat cohesion property by naphthalenedicarboxylic acid can be obtained. A resin having both of them can be obtained.

The polyester resin in the present invention can be obtained, for example, by conducting a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components (A) and (B) in the presence of a catalyst. The reaction temperature and reaction time at this time are
Although not particularly limited, usually 150 to 300 ° C.
For 2 to 24 hours.

As a catalyst for carrying out the above reaction, for example, tetrabutyl titanate, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, paratoluenesulfonic acid and the like can be appropriately used.

The polyester resin used in the present invention preferably has a glass transition temperature (Tg) of 50 ° C. or higher, and particularly preferably has a Tg of 55 ° C. or higher. When the Tg is 50 ° C. or lower, a blocking phenomenon (thermal aggregation) tends to occur when the toner is stored, transported, or exposed to a high temperature inside a developing device of a machine.

The softening point of the polyester resin used in the present invention is 90 ° C. or higher, especially 90 ° C. to 1 ° C.
It is preferably in the range of 80 ° C, more preferably 95%.
C. to 160.degree. When the softening point is lower than 90 ° C., the toner is liable to cause agglomeration, and when storing or printing, trouble tends to occur.

Further, as a full-color toner, in particular,
When color reproducibility at the time of color superposition or transparency when fixed on an OHP sheet is required, the softening point of the polyester resin is preferably in the range of 90 ° C to 130 ° C, more preferably , 95 ° C to 120 ° C.

The acid value of the polyester resin of the present invention is preferably 20 mgKOH / g or less in that the moisture resistance of the toner becomes good.

In the present invention, a naphthol-based organic pigment represented by Chemical Formula 1 is used as an essential component, but other colorants may be added to adjust the hue. Examples of such coloring agents include well-known coloring agents,
For example, phthalocyanine C.I.
I. Pigment Blue 15-3, indanthrone C.I. I. Pigment Blue 60 and the like are quinacridone-based C.I. I. Pigm
ent Red 122, an azo C.I. I. Pigmen
t Red 22, C.I. I. Pigment Red 4
8: 1, C.I. I. Pigment Red 48: 3,
C. I. Pigment Red 57: 1, etc., and an azo-based C.I. I. Pigment Ye
low 12, C.I. I. Pigment Yellow
13, C.I. I. Pigment Yellow 14,
C. I. Pigment Yellow 17, C.I. I.
Pigment Yellow 97, C.I. I. Pigm
ent Yellow 155, isoindolinone-based C.I. I. Pigment Yellow 110, a benzimidazolone C.I. I. Pigment Yellow
w 151, C.I. I. Pigment Yellow 1
54, C.I. I. Pigment Yellow 180,
Etc.

In the toner of the present invention, various known waxes, for example, polypropylene wax, polyethylene wax, polyamide wax, Fischer-Tropsch wax, synthetic ester wax, various natural waxes, etc. may be appropriately used as a releasing agent. Among them, natural waxes such as carnauba wax, montan ester wax, rice wax and scale insect wax, and / or tetrabehenic acid ester of pentaerythritol, which is a synthetic ester wax, are particularly preferable. These waxes show the best dispersibility in the polyester resin having the structure according to the present invention, and the fixing property and the offset resistance are remarkably improved.

As the carnauba wax, it is preferable to use a free fatty acid-type carnauba wax from which free fatty acids have been removed by purification. The acid value of the free fatty acid-type carnauba wax is preferably 8 or less, more preferably 5 or less. The free fatty acid type carnauba wax becomes finer crystals than the conventional carnauba wax, and the dispersibility in the polyester resin is improved. The montan-based ester wax is refined from a mineral, and becomes fine crystals like the carnauba wax by the purification, so that the dispersibility in the polyester resin is improved. The acid value of the montan ester wax is particularly preferably 30 or less. Rice wax is obtained by refining rice bran wax, and preferably has an acid value of 13 or less. The scale insect wax is the scale insect (also known as the larva)
The waxy components secreted by the larvae are, for example, dissolved in boiling water,
It can be obtained by cooling and solidifying the upper layer after separation, or by repeating the same. The scale insect wax purified by such a means is white in a solid state, has an extremely sharp melting point, and is suitable as a toner wax in the present invention. The acid value is reduced to 10 or less due to purification, and is preferably 5 or less for toner.

The above waxes may be used alone or in combination.
A good fixing offset performance can be obtained by adding 1 part by weight, preferably 1 to 5 parts by weight. When the amount is less than 0.3 parts by weight, the offset resistance is impaired, and when the amount is more than 15 parts by weight, the fluidity of the toner is deteriorated. It adversely affects the charging characteristics of the toner, and adheres to the layer thickness regulating member pressed against the developing roll in the non-magnetic one-component developing system.

In the present invention, a charge control agent can be used if necessary. For example, a nigrosine dye, a triphenylmethane dye, a quaternary ammonium salt, a resin containing a quaternary ammonium group and / or an amino group as a positive charge control agent, a trimethylethane dye, a metal of salicylic acid as a negative charge control agent Complex salts, metal complex salts of benzylic acid, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex salt azo dyes, acid dyes containing heavy metals such as azochrome complexes, calixarene-type phenolic condensates, cyclic polysaccharides, carboxyl groups And / or a resin containing a sulfonyl group.

In particular, in the present invention, it is desirable to use a colorless charge control agent. As a metal complex compound of salicylic acid, "Bontron E-84" manufactured by Orient Chemical Co., Ltd. is used.
As the metal complex compound of benzylic acid, "LR-147" and "LR-297" manufactured by Nippon Carlit are preferably used as a colorless negative charge control agent. Although the structure is not clear, “TN-105” manufactured by Hodogaya Chemical can also be suitably used as a colorless negative charge control agent. Further, as a colorless positive charge control agent, TP- having a quaternary ammonium salt structure is used.
302, TP-415, TP-610; (manufactured by Hodogaya Chemical), Bontron P-51; (manufactured by Orient Chemical), Copy Charge PSY (Clariant Japan) and the like are preferably used.

The positively chargeable resin-type charge control agent containing a quaternary ammonium group and / or an amino group includes:
"FCA-201-PS" (Fujikura Kasei Co., Ltd.) and the like.

The production method for obtaining the toner of the present invention is as follows.
It can be obtained by any known and commonly used means. For example, after melt-kneading a resin, a colorant, a wax, and various additives as necessary at a temperature equal to or higher than the melting point (softening point) of the resin, pulverizing,
It can be obtained by classification. The colorant is flushed in advance so that it is evenly dispersed in the resin.
Alternatively, a master batch melt-kneaded with a resin at a high concentration may be used.

Specifically, for example, the above-mentioned resin, colorant, and wax are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader, or a twin-screw extruder. At this time, the colorant may be uniformly dispersed in the resin, and the conditions for the melt-kneading are not particularly limited, but are generally at 80 to 180 ° C. for 10 minutes to 2 hours. The kneaded material is usually cooled by a cooling belt, a roller, or the like, but since the dispersion state of the release agent changes depending on the cooling conditions, the cooling conditions can be set so as to obtain a desired dispersion state.

If necessary, coarse pulverization is performed for the purpose of reducing the load in the fine pulverization step and improving the pulverization efficiency. The apparatus and conditions used for the coarse pulverization are not particularly limited, but the coarse pulverization is generally performed using a rotoplex, a pulperizer, or the like to a particle size of 3 mm mesh pass or less.

Next, fine pulverization is performed by a mechanical pulverizer such as a turbo mill or a kryptron, or an air pulverizer such as a spiral jet mill, a counter jet mill, or an impingement plate jet mill, and then classified by an air classifier or the like. No. Fine grinding and classification equipment, conditions are the desired particle size,
What is necessary is just to select and set it so that it may become a particle size distribution and a particle shape.

In the present invention, various additives (referred to as external additives) can be used for modifying the surface of the toner base such as improving the fluidity of the toner and improving the charging characteristics. Examples of the external additives that can be used in the present invention include inorganic fine powders such as silicon dioxide, titanium oxide, aluminum oxide, cerium oxide, zinc oxide, tin oxide, and zirconium oxide, and silicone oils and silane coupling agents. Surface-treated with a hydrophobizing agent such as polystyrene, acryl, styrene acryl, polyester, polyolefin, cellulose, polyurethane, benzoguanamine, melamine, nylon, silicone, phenol, vinylidene fluoride, and Teflon (registered trademark). Are used.

Among these, silicon dioxide (silica) whose surface is hydrophobized with various polyorganosiloxanes, hexamethylenedisilazane, a silane coupling agent or the like can be particularly preferably used. As such,
For example, there is one that is commercially available under the following trade names.

AEROSIL R972, R974, R202, R805, R812, RX200, RY200, R809, RX50, RA200HS, RA200H [Nippon Aerosil Co., Ltd.] WACKER HDK H2000, H1018, H2050EP HDK H3050EP, HVK2150 [Waker Chemical Yeast )] Nipsil SS-10, SS-15, SS-20, SS-50, SS-60, SS-100, SS-50B, SS-50F, SS-10F, SS-40, SS-70, SS-72F [Nippon Silica Kogyo Co., Ltd.] CABOSIL TG820F, TS-530, TS-720 [Cabot Specialty Chemicals, Inc.] The particle size of the external additive is one of the diameter of the colored particles as the base toner.
/ 3 or less, particularly preferably 1/10
It is as follows. Further, these external additives may be used in combination of two or more kinds having different average particle diameters.

In particular, in the case of a non-magnetic one-component developing toner, by using both a large particle size toner and a small particle size toner, the toner fluidity and development durability are improved, and the toner is fixed to the blade of the developing machine. In addition, it is preferable because it can prevent fogging and long-term stability of charging during running.

The proportion of the external additive is 0.05 to 5% by weight, preferably 0.1 to 5% by weight, based on 100 parts by weight of the base toner.
3% by weight.

As a method of externally adding the silica to the toner particles, for example, a conventional powder mixer such as a Henschel mixer or a so-called surface modifier such as a hybridizer can be used. In this external addition process, silica may be attached to the surface of the toner particles, or a part of the silica may be embedded in the toner particles.

As a developing method using the toner of the present invention as a non-magnetic one-component developing toner, the toner of the present invention is carried on a developing sleeve without being mixed with a carrier, and the toner is used as a photosensitive member having an electrostatic latent image. There is a contact type non-magnetic one-component developing method in which development is performed by contacting with a drum.

The non-magnetic one-component developing toner of the present invention is triboelectrically charged by passing the toner between the developing sleeve and the layer thickness regulating member pressed against the developing sleeve, and then forms a static charge on the surface of the photoreceptor. It can be used particularly effectively in a contact-type non-magnetic one-component developing method for developing an electrostatic latent image.

The non-magnetic one-component developing toner in the present invention does not particularly limit the material and the like of the charging member of the developing device under ordinary use conditions. For example, aluminum, stainless steel, urethane rubber, silicon rubber developing sleeve, aluminum, stainless steel, duralumin,
Copper or a layer thickness regulating member obtained by bonding urethane rubber or silicon rubber to them or the like can be suitably used.

A developing method suitable for the toner of the present invention to exhibit its effects is a case where one of the developing sleeve and the layer thickness regulating member is a metal such as aluminum or stainless steel. Developing sleeve / layer thickness regulating member) is a combination of a urethane rubber or silicone rubber developing sleeve and a stainless steel layer thickness regulating member,
Alternatively, it is a combination of a developing sleeve made of stainless steel and a layer thickness regulating member made of urethane rubber or silicon rubber.

When the electrostatic image developing toner of the present invention is used in a two-component developing system, the following carriers can be used.

As the core agent of the carrier, iron powder, magnetite, ferrite and the like used in a usual two-component developing system can be used. Among them, since the true specific gravity is low, the resistance is high, the environmental stability is excellent, and the sphere is easily formed. Ferrite or magnetite having good fluidity is preferably used. The shape of the core agent can be used without any particular problem, such as spherical or amorphous.
The average particle size is generally 10 to 500 μm, but is preferably 30 to 80 μm for printing a high-resolution image.

Examples of coating resins for covering these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, and vinyl chloride. / Vinyl acetate copolymer, styrene / acrylic copolymer, straight silicone resin comprising organosiloxane bond or its modified product, fluororesin, (meth) acrylic resin, polyester, polyurethane, polycarbonate, phenolic resin, amino resin, melamine resin , Benzoguanamine resin, urea resin, amide resin, epoxy resin, acrylic polyol resin and the like can be used. Among these,
In particular, silicone resins, fluororesins, and (meth) acrylic resins are excellent in charge stability, coating strength, and the like, and can be more preferably used. That is, the resin-coated carrier used in the present invention is:
It is preferable that the magnetic carrier is a resin-coated magnetic carrier that uses ferrite or magnetite as a core agent and is coated with at least one resin selected from silicone resins, fluororesins, and (meth) acrylic resins.

[0053]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In the following, numerical values in the composition table represent "parts by weight". An example of the synthesis of the binder resin used in preparing the toner first is shown below. (Resin Synthesis Example 1) Naphthalenedicarboxylic acid 87 parts by weight Terephthalic acid 249 parts by weight Diethylene glycol 26 parts by weight Neopentyl glycol 104 parts by weight Ethylene glycol 50 parts by weight Tetrabutyl titanate 2.5 parts by weight The reaction mixture was placed in a flask, fitted with a thermometer, a stirring rod and a nitrogen inlet tube, and reacted at 240 ° C. for 10 hours in an electric heating mantle heater under a normal nitrogen flow, and then the pressure was reduced in sequence, and the reaction was continued at 10 mmHg. The reaction is ASTM
・ Tracking by softening point according to E28-517, softening point is 101 ℃
When the reaction reached, the reaction was terminated.

The obtained polymer (hereinafter referred to as resin A)
Was a colorless solid, had an acid value of 7, a glass transition temperature of 70 ° C by DSC measurement, and a softening point of 102 ° C. (Resin Synthesis Example 2) Terephthalic acid 315 parts by weight Diethylene glycol 21 parts by weight Cyclohexanedimethanol 144 parts by weight Ethylene glycol 50 parts by weight Tetrabutyl titanate 2.5 parts by weight A reaction was carried out in the same manner as in Resin Synthesis Example 1 using the above raw materials. Was. The obtained polymer (hereinafter referred to as resin B) was a colorless solid, having an acid value of 9, and a glass transition temperature of 60 as measured by DSC.
° C and the softening point was 97 ° C.

(Comparative Synthesis Example 1) Polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane 64 parts by weight Isophthalic acid 16 parts by weight Terephthalic acid 16 parts by weight Maleic anhydride 0. 6 parts by weight Dibutyltin oxide 0.06 parts by weight Put the above raw materials into a glass 2L four-necked flask, attach a thermometer, stir bar and nitrogen inlet tube, and in an electric heating mantle heater under a normal pressure nitrogen stream. After reacting at 230 ° C. for 24 hours, the pressure was sequentially reduced, and the reaction was continued at 10 mmHg. The reaction is ASTM
・ Tracking by softening point according to E28-517, softening point is 99 ℃
When the reaction reached, the reaction was terminated.

The obtained polymer (hereinafter referred to as resin C)
Was a colorless solid, had an acid value of 7, a glass transition temperature of 62 ° C by DSC measurement, and a softening point of 101 ° C.

Example 1 <Preparation of Toner> Resin A 94 parts by weight Naphthol-based pigment represented by Chemical Formula 1 3 parts by weight Purified carnauba wax No. 1 1 2 parts by weight of "Cerarica NODA" (acid value 5) Charge control agent LR-147 1 part by weight of "Nippon Carritt" After mixing the above raw materials with a ball mill, kneading with a heating roll, cooling, and then jet milling And pulverized and classified to prepare a toner having an average particle diameter of 11 μm. Next, this finely pulverized material 10
0 parts by weight of Nippon Aerosil silica "R-81"
2) 1 part by weight of an external additive was added to obtain a magenta toner (hereinafter, referred to as “toner (1)”).

<Adjustment of Developer> 4 parts of toner (1) and a carrier “Ferrite carrier F-15” manufactured by Powder Tech Co., Ltd.
The developer was adjusted by friction mixing 96 parts of “0”.

<Reproducibility of Red> As a yellow pigment, disazo yellow pigment "Symuler Fa" manufactured by Dainippon Ink and Chemicals, Inc.
st Yellow 5GP "and a copper phthalocyanine pigment" Fastogen Blu "manufactured by Dainippon Ink and Chemicals, Inc.
A yellow developer and a cyan developer were prepared in the same manner as in <Production of Toner> and <Adjustment of Developer> except that “e GNPT” was used.

Using a copier "BD-3504" manufactured by Toshiba Corp., a full-color copy was performed by superimposing three colors together with the developer prepared using the toner (1), and red reproducibility was visually evaluated. The results are shown in Table 1.

<Hue and Hue Characteristics> The red copy image in <Red Reproducibility> was measured for lightness using a color difference meter “Minolta CM-1000 Spectral Colorimeter” manufactured by Minolta Camera Co., Ltd. (Table 1).
And the hue (indicated by “a *, b *” in Table 1) and the saturation (indicated by “a *, b *” in Table 1).
The results are shown in Table 1. In addition, L * means a lightness coordinate axis in the hue coordinates, a * means a red-green coordinate axis of hue / saturation coordinates, and b * means a yellow-blue coordinate axis of hue / saturation coordinates.

<Heat Resistance Coagulation Test> Toner 10 before mixing with carrier in 100 cc cylindrical polycup without lid
g was put in a thermostat set at 65 ° C. 2
After a lapse of 4 hours, the polycup was taken out, and the toner inside was discharged by slowly tilting the polycup on a horizontal table. At that time, there is no aggregation due to fusion of the toner particles, and the state where the toner powder spreads on the table is ○, there is a little aggregation, but the state where it is easily loosened with a finger is Δ, The state in which the shape of the polycup as it was in the polycup while being kept almost was evaluated as x. The results are shown in Table-2.

<Fixing Offset Test by Heat Roll Fixing> An unfixed image sample of A-4 paper size was prepared using a test machine modified from a commercially available two-component developing type copying machine, and a heat roll fixing unit having the following specifications was mounted. The fixing start temperature and the presence or absence of an offset phenomenon were confirmed under the following test conditions. In order to measure the fixing start temperature, an image density remaining ratio calculated by the following equation was obtained.

Image density residual ratio = image density after fastness test / image density before left test * Image density was measured by Macbeth image densitometer RD-918. * The image density after fastness test is the image density after rubbing the fixed image using a Gakushin type friction fastness tester (load: 200 g, rubbing operation: 5 strokes).

An image density remaining ratio of 80% or more was set to a level at which there is no practical problem, and the lowest temperature was defined as a fixing start temperature.

The offset start temperature was a temperature at which the offset phenomenon was visually observed by observing the fixed image sample. The results are shown in Table-2.

<Print Durability Test> Using a copying machine “BD-3504” manufactured by Toshiba Corp., the density of the image area and the density of the background stain after continuous printing of 50,000 sheets were measured, and the charge amount of the developer was measured. . Image density and background stain were measured with a Macbeth densitometer RD-918. The background stain was obtained by subtracting the density of the white paper before printing from the density of the white background after printing. When the difference was less than 0.01, it was evaluated as ○, when it was less than 0.01 to 0.03, Δ, and when it was 0.03 or more, ×.

The charge amount was measured with a blow-off charge amount measuring device by collecting toner from the inside of the developing device for each number of printed sheets. The results are shown in Table-2.

Example 2 <Preparation of Toner> A toner (hereinafter referred to as “toner (2)”) was prepared in the same manner as in Example 1 except that the resin in Example 1 was changed to resin B. did. <Adjustment of Developer> The developer was adjusted in the same manner as in (Example 1) except that the toner (2) was used.

Example 3 <Preparation of Toner> The purified carnauba wax No. 1 in Example 1 was used. A toner (hereinafter, referred to as “toner (3)”) was prepared in the same manner as in Example 1 except that 1 was changed to tetrabehenic acid ester of pentaerythritol. <Adjustment of Developer> The developer was adjusted in the same manner as in (Example 1) except that the toner (3) was used.

(Example 4) <Preparation of Toner> A toner (hereinafter, referred to as “toner (4)”) was produced in the same manner as in Example 1, except that Resin A was used in an amount of 96 parts by weight without using Resin A. <Adjustment of Developer> The developer was adjusted in the same manner as in (Example 1) except that the toner (4) was used.

(Comparative Example 1) <Preparation of Toner> The same procedure as in Example 1 was carried out except that the naphthol-based pigment represented by the chemical formula 1 was replaced by an azo lake pigment (CIPigment Red 57: 1) represented by the following chemical formula 2. A toner (hereinafter, referred to as “comparative toner (1)”) was prepared in the same manner as in Example 1. Chemical structural formula 2

[0073]

Embedded image

<Adjustment of Developer> The developer was adjusted in the same manner as in (Example 1) except that the comparative toner (1) was used.

Comparative Example 2 <Preparation of Toner> The procedure of Example 2 was repeated except that the naphthol-based pigment represented by the chemical formula 1 in Example 2 was changed to "quinacridone-based pigment Pigment Red 122" described in JP-A-51-24234. A toner (hereinafter, referred to as “comparative toner (2)”) was prepared in the same manner as in Example 2. <Adjustment of developer> The developer was adjusted in the same manner as in (Example 2) except that the comparative toner (2) was used.

Comparative Example 3 <Preparation of Toner> Toner (hereinafter, referred to as “Comparative Toner (3)”) in the same manner as in Example 1 except that resin A was used instead of resin A. Was prepared. <Adjustment of Developer> The developer was adjusted in the same manner as in (Example 1) except that the comparative toner (3) was used.

Comparative Example 4 <Preparation of Toner> Toner (hereinafter, referred to as “Comparative Toner (4)”) in the same manner as in Example 4 except that resin B was used instead of resin B in Example 4. Was prepared. <Adjustment of developer> The developer was adjusted in the same manner as in (Example 4) except that the comparative toner (4) was used.

Examples 2 to 4 and Comparative Examples 1 to 4 obtained above.
The toner of No. 4 was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Table 1

[0080]

[Table 1]

Table 2

[0082]

[Table 2]

The indications in the table are as follows. * "Charge amount"; μC / g * "Stain evaluation" ○: less than 0.01, Δ: 0.01 to less than 0.03,
A: 0.03 or more (Example 5) The dedicated toner is removed from the cartridge of a commercially available non-magnetic one-component developing type printer, and the washed cartridge is filled with the toner of Example 1 (toner (1)).
A continuous printing test was performed on 10,000 sheets. As a result, even after continuous printing, the toner layer on the developing sleeve was uniform, and no defect occurred. In addition, there was no change in the image density at the beginning of printing and after continuous printing, and an image of good print quality without image loss or background stain was obtained.

(Comparative Example 5) Continuous printing was performed in the same manner as in Example 5 except that the toner (Comparative Toner (3)) of Comparative Example 3 was used instead of the toner (Toner (1)) of Example 1. Tested. As a result, the toner layer on the developing sleeve after continuous printing was non-uniform, and streak-like defects occurred in the circumferential direction of the developing sleeve. Further, in the layer thickness regulating member pressed against the developing sleeve, a fixed substance was observed at a portion in contact with the developing sleeve. Furthermore, as the number of prints increased, the image density decreased, streak-like stains were observed in the developing direction, and background stains increased, resulting in a print image with poor print quality.

[0085]

According to the present invention, in a so-called multicolor superimposition using a yellow pigment-containing toner and a blue pigment-containing toner in combination, which is excellent in color reproducibility, gives good and stable transfer image quality, and is used in combination. Magenta toner capable of obtaining a clear image very close to a natural color. The toner of the present invention can be used as a magenta toner having particularly excellent red reproducibility.

Further, the toner of the present invention is excellent in low-temperature fixing and offset resistance, and exhibits excellent thermal characteristics in heat roll fixing under low energy conditions during high-speed printing. Incidentally, the toner of the present invention has sufficiently excellent performance not only for the full-color application shown in the above-mentioned embodiment but also as a monocolor toner.

Claims (2)

[Claims] 1. A color toner for developing an electrostatic image comprising a binder resin and an organic pigment, wherein the binder resin comprises: (A) a dibasic or higher polybasic acid and / or an acid anhydride and / or a lower thereof. A polybasic acid compound selected from alkyl esters (B) a polyester resin having a dihydric or higher aliphatic polyhydric alcohol as a main component, wherein the organic pigment is a naphthol-based organic pigment having the following structure: Color toner for developing electrostatic images. Chemical structural formula 1 2. The color toner for developing an electrostatic image according to claim 1, further comprising a release agent.