JPH11143134A - Toner mother particle, toner and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrostatic charge image developing toner mother particles with which sharp and enough color reproducibility and color developing property can be obtd. when a full-colored image is formed by using a full-color copying machine or printer, and especially, when a full-colored image is formed on a transparent base body such as an OHP sheet, significant transparency of the image can be obtd., and to provide a toner and a developer prepared by using the toner mother particles. SOLUTION: The toner mother particles are prepared by heating and kneading a water-based paste (E) of a treated pigment and a resin (F) which is solid at normal temp., then removing the water content from the kneaded material to obtain a resin-coated pigment (G), and then heating and kneading the pigment (G) with a binder resin (H). The treated pigment for the water-base paste (E) is obtd. by mechanically kneading a mixture comprising at least four components of (A) an org. pigment, (B) a synthetic resin which is solid at room temp. and insoluble with water, (C) a water-soluble inorg. salt and (D) a water- soluble solvent which at least partly dissolve (B), and then removing (C) and (D) by washing with water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner base particle for developing an electrostatic image used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like, and the toner base particle. And a developer formed using the toner. More specifically, when copying or the like is performed using magenta, cyan, yellow, and black toners, a clear and sufficient color reproducibility, a toner mother particle for developing an electrostatic image capable of obtaining color development, and the toner mother particles are provided. The present invention relates to a toner and a developer formed by use.

[0002]

2. Description of the Related Art In recent years, the development of full-color images in copying machines, printers, and the like has been rapidly progressing, and their practical use has been greatly increased. However, compared to photographs and printed matter, it is hard to say that a full-color electrophotographic image currently in practical use has reached a satisfactory image quality. In recent years, with the advancement and development of computers, high-definition televisions, and the like, there is a strong demand for a method of forming a higher-definition full-color image. For this reason, there is a strong demand for further improving the quality of full-color electrophotographic images.

In electrophotography, an electrostatic latent image is generally developed using toner. The methods are roughly classified into a method using a two-component developer in which a small amount of toner is dispersed in a medium called a carrier, and a method using a one-component developer without using a carrier. For full color electrophotography,
A two-component developer in which a carrier and a toner are mixed and used is often used.

In color image formation by full-color electrophotography, all colors are reproduced by using three color toners of three primary colors, magenta, cyan and yellow, and preferably four color blacks for inking. Things.
In this method, for example, light from a document is first subjected to analog or digital color separation and guided to a photoconductive layer of a photoreceptor to form an electrostatic latent image of the first color. Subsequently, the toner is held on a transfer material such as paper through a development and transfer process. Further, for the second and subsequent colors, the above-described steps are sequentially performed a plurality of times, and the toners of a plurality of colors are superimposed on the same material to be transferred, and a final full-color image is obtained by one-time fixing.

[0005] The use of full-color copying machines, full-color printers and the like to form full-color images on transparent substrates such as sheets for overhead projectors (hereinafter abbreviated as OHP) has been increasing. Today, toners used for full-color image formation are required to have various properties, such as stable chargeability and good fluidity, as in the case of the most common conventional black toners.
Transparency, sharpness, color reproducibility and the like are further required.

That is, since a full-color image is obtained by superimposing a plurality of color toners on the transfer material as described above, if the light transmittance of each toner is insufficient, the color reproducibility deteriorates. It is difficult to obtain a clear image. This phenomenon is particularly remarkable when a full-color image is formed on a transparent substrate such as an OHP sheet, and it is difficult to obtain a good transparent image.

As a countermeasure, it is conceivable to increase the degree of dispersion of the pigment, that is, to reduce the particle size of the pigment in the toner. Generally, as the particle size of the pigment is reduced to increase the degree of dispersion, the transparency of the pigment dispersion is improved. However, ordinary dispersing machines such as a sand mill, a three-roll mill, a ball mill, and an extruder mainly break only secondary particles (primary particles are weakly agglomerated) of pigment into primary particles. And the like, it is difficult to make the pigment finer. By using a high-speed sand mill or the like, it is possible to further refine the pigment depending on the kind of the pigment, but it requires a very large amount of energy.

As means for making the primary particles of the pigment fine,
There is known a method in which a pigment is dissolved in a strong acid such as concentrated sulfuric acid or polyphosphoric acid, and the solution is poured into cold water to precipitate the pigment as fine particles. In this method, the pigments that can be used are significantly limited in terms of solubility and stability of the pigment in strong acids.
In addition, since pigments finely divided by this method cause strong secondary aggregation when dried, it is very difficult to re-disperse the dried pigment to primary particles.Also, as a method for improving dispersibility, alcohol is used. However, it is known that heat treatment is performed in a solvent such as these, but undesired crystal growth occurs and the pigment particle size increases.

As another method for making the pigment finer, a method is known in which the pigment and the solid resin are heated and kneaded with a two-roll mill or a Banbury mixer while heating. However, since pigments generally grow at high temperatures, in such a method, the end point is reached when mechanical crushing and crystal growth are in an equilibrium state, and there is a limit to the fineness of the pigment.

Further, as a method of making the primary particles of the pigment fine, a mixture of the pigment and a water-soluble inorganic salt such as salt is moistened with a small amount of a water-soluble solvent, kneaded strongly with a kneader or the like, and then mixed with the inorganic salt. There is a method in which the solvent is washed away with water and dried to obtain a pigment having fine primary particles. This method is generally known as a pigmentation method of β-type copper phthalocyanine in which crude copper phthalocyanine is mechanically ground in the presence of a water-soluble organic solvent by using salt as a grinding agent. In this case, the water-soluble organic solvent is used as a binder and to prevent the β-type crystal from being crystallized to the α-type crystal due to the mechanical shearing force of the kneader. In general, this method is called solvent salt milling, and is distinguished from a method of simply mechanically reducing the size without using a grinding agent (called dry milling). In a broad sense, salt milling without using a solvent is also called drying. However, this method has a problem in that strong secondary aggregation of the pigment easily occurs during drying, and the pigment particle size becomes large.

[0011] A resin or a resin solution is added to an aqueous slurry or an aqueous cake containing a pigment at a high concentration before drying,
A method of mixing and stirring, replacing the water around the pigment with a resin or a resin solution, and then removing the water and the solvent is generally called flushing. In this method, since there is no step of drying the pigment, the aggregation of the pigment hardly occurs, and the pigment particles can be coated with the resin in a fine state. Can be

As the formation of full-color images using color toners has become common, the quality desired by users has improved, and the quality of electrophotography has been required to be as high as that of ordinary silver halide photography. . Therefore, the dispersion of the pigment in the toner is improved even more than in the case where the conventional flushing treatment pigment is used, the light transmittance at the time of forming an image is improved, and the toner of multiple colors is superimposed on the same transfer material. When a full color image is formed
To obtain color reproducibility closer to the original. The dispersion of the pigment in the toner is further improved so that the pigment is sufficiently colored and a good image with a high density can be obtained. When a full-color image is formed on a transparent substrate such as an OHP sheet, the sharpness and transparency of the image are improved. Is required.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a toner for developing an electrostatic image capable of obtaining clear and sufficient color reproducibility and color development when a full-color image is formed using a full-color copying machine or printer. It is an object of the present invention to provide a base particle, and a toner and a developer using the toner base particle. In particular, it is an object of the present invention to provide a toner base particle for developing an electrostatic image capable of obtaining remarkable transparency when a full-color image is formed on a transparent substrate such as an OHP sheet, and a toner and a developer using the toner base particle. Aim.

[0014]

The first invention comprises an organic pigment (A), a synthetic resin (B) which is solid at room temperature and insoluble in water,
Mechanically kneading a mixture comprising at least four components of a water-soluble inorganic salt (C) and a water-soluble solvent (D) which at least partially dissolves a synthetic resin (B) which is solid and water-insoluble at room temperature; Thereafter, an aqueous paste (E) of the treated pigment obtained by washing and removing (C) and (D) and a resin (F) which is a solid at room temperature are heated and kneaded, and then the resin-coated pigment (G) obtained by removing water is obtained. ) And a binder resin (H) by heating and kneading the toner mother particles for electrostatic image development.

A second invention is characterized in that the organic pigment (A) is one selected from the group consisting of quinacridone organic pigments, phthalocyanine organic pigments, and azo organic pigments. Are the toner base particles for developing an electrostatic image.

The third invention is characterized in that 1 to 100 parts by weight of a synthetic resin (B) which is solid at room temperature and is insoluble in water is used with respect to 100 parts by weight of the organic pigment (A). The toner mother particles for electrostatic image development according to the second aspect.

The fourth invention is characterized in that the water-soluble inorganic salt (C) is used in a weight ratio of 2 to 20 times the water-soluble solvent (D) in the first to third inventions. The toner base particles for developing an electrostatic image according to any one of the above.

According to a fifth aspect of the present invention, there is provided a toner for developing an electrostatic image, comprising a mixture of the toner base particles for developing an electrostatic image according to any one of the first to fourth aspects and an external additive. It is.

According to a sixth aspect of the present invention, there is provided a developer comprising a mixture of the toner for developing an electrostatic image according to the fifth aspect of the present invention and a carrier.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a so-called water-insoluble synthetic resin (B) which is solid at room temperature at the time of so-called salt milling, in which an inorganic salt is used as a crushing aid and the primary particles of an organic pigment are mechanically fined, is used. It is important to flush the pigment without drying it after use and such salt milling. The present invention comprises adding a small amount of a water-soluble solvent (D) as a wetting agent to a mixture of an organic pigment (A), a synthetic resin (B) which is solid and water-insoluble at room temperature, and a water-soluble inorganic salt (C); After strongly kneading with a kneader or the like, the mixture is poured into water to dissolve the water-soluble inorganic salt (C) and the water-soluble solvent (D) to form a slurry. By removing (C) and the solvent (D), an aqueous paste (E) of a finely divided organic pigment is obtained. Pigment particles refined by salt milling may re-agglomerate as they are. However, when salt milling is performed in the presence of a synthetic resin (B) which is solid and water-insoluble at room temperature, the finely divided organic pigment (A The surface of the pigment particles is coated with the synthetic resin (B) to prevent re-aggregation.

Then, the aqueous paste (E) of the treated pigment is heated and kneaded with the resin (F) at room temperature to form a resin-coated pigment (G) obtained by coating the treated pigment with the resin (F) at room temperature. ), So-called flushing pigments are obtained. By preventing the agglomeration of the pigment by flushing without drying subsequent to the salt milling, by using the resin-coated pigment (G) in the state of undried finely divided pigment particles as a colorant of the toner base particles, This makes it possible to obtain an image having much better sharpness and transparency than before.

The organic pigment (A) used in the present invention is not particularly limited as long as it does not dissolve in water. However, inorganic pigments in which the hardness of the organic pigment (A) is greater than the water-soluble inorganic salt (C) of the crushing aid or that has little difference are generally difficult to make the primary particles of the pigment finer, and have low hardness. It is preferred to use organic pigments. However, inorganic pigments such as barium sulfate and silica, which are generally used as extenders, may be used together during salt milling or during subsequent dispersion.

Examples of the organic pigment (A) include insoluble azo pigments such as toluidine red, toluidine maroon, hansa yellow, benzidine yellow, and pyrazolone red; Derivatives from vat dyes such as alizarin, indanthrone and thioindigo maroon; phthalocyanines such as phthalocyanine blue and phthalocyanine green; quinacridones such as quinacridone red and quinacridone magenta; perylenes such as perylene red and perylene scarlet; Isoindolinones such as Linone Yellow and Isoindolinone Orange, Pyranthrones such as Pyranthrone Red and Pyranthrone Orange, Thioindigo, Condensed Azo, Thioindigo As other pigments, Flavanthrone Yellow, Acylamide Yellow, Quinophthalone Yellow, Nickel Azo Yellow, Copper Azomechin'ero, Yellow, Perinone Orange, Anthrone Orange, Dianthraquinonyl Red, dioxazine violet and the like are used.

Examples of such pigments include the following pigments. Indicated by color index (CI) number. CI Pigment Yellow 12, 13, 14, 17, 2
0, 24, 74, 83, 86, 93, 109, 110,
117, 125, 137, 138, 147, 148, 1
53, 154, 166, 168, CI Pigment Orange 13, 16, 36, 43, 51, 55, 59, 61,
CI Pigment Red 9, 48, 49, 52, 53, 5
7, 97, 122, 123, 149, 168, 177,
180, 192, 215, 216, 217, 220, 2
23, 224, 226, 227, 228, 238, 24
0, CI Pigment Violet 19, 23, 29, 3
0, 37, 40, 50, CI Pigment Blue 15, 1
5: 1, 15: 4, 15: 6, 22, 60, 64, CI
Pigment Green 7, 36, CI Pigment Brown 23, 25, 26, and the like.

Among them, quinacridone organic pigments,
It is preferable to use one selected from the group consisting of phthalocyanine organic pigments and azo organic pigments. Further, a surface-treated pigment obtained by adding a functional group to the surface of these pigments may be used. Further, in addition to these pigments, two or more pigments may be mixed and treated.

In the present invention, among the toner base particles, in the case of black toner base particles, three colored processing pigments of yellow, cyan and red are obtained, and these three colored processing pigments may be used as a colorant. . In the present invention, among the toner base particles, in the case of black toner base particles, the use of carbon black as a colorant is not prevented. As the carbon black, all known ones such as channel black, furnace black and lamp black can be used.

The synthetic resin (B) which is solid at room temperature and is insoluble in water used in the present invention includes, in addition to pure synthetic polymers, semi-synthetic polymers such as cellulose derivatives, rubber derivatives and protein derivatives. These oligomers are also included. However, it must be solid at room temperature, insoluble in water, and soluble in a water-soluble solvent used as a wetting agent during salt milling. Salt milling can also be performed using two or more polymers in combination. In that case, a partially liquid polymer may be used. Among these resins, epoxy resins and (meth) acrylic resins are particularly versatile and have a great effect of salt milling.

The epoxy resin used in the present invention refers to an epoxide containing one or more epoxy groups in the molecule, and an epoxy resin crosslinked with a curing agent generally has little solubility and a water-soluble solvent described later. Since it hardly dissolves in (D), it is not used in the present invention. Epoxides include bisphenols, novolaks, alkylphenols, resorcinols, polyglycols, esters,
A glycidyl type such as N-glycidylamine, a cyclic aliphatic epoxide and the like are used.

The (meth) acrylic resin used in the present invention is a copolymer of acrylic acid and / or methacrylic acid and one or more acrylate monomer and / or methacrylate monomer, and is 60 mol% or less. And a copolymer with a radically polymerizable monomer such as styrene, vinyl acetate, and maleic anhydride. However, a three-dimensionally crosslinked polymer, such as a copolymer with a polyfunctional monomer, has poor solubility and is hardly soluble in a water-soluble solvent (D) described below, and is not suitable for the present invention.

In the present invention, the organic pigment (A) can be miniaturized without the intervention of the synthetic resin (B) during salt milling. However, since organic pigments are generally very easy to aggregate, fine pigments can be flashed as they are by salt milling in the presence of the synthetic resin (B). Can be provided.

The synthetic resin (B) which is solid at room temperature and is insoluble in water used in the present invention is an organic pigment (A) 100
It is desirable to use 1 to 100 parts by weight, more preferably 5 to 50 parts by weight with respect to parts by weight. When the amount of the resin is small, the coating effect is small, the fine primary particles are easily aggregated, and it is difficult to obtain transparency when an image is formed.
Conversely, if the amount is too large, the amount of binder resin added thereafter is limited, or when another type of resin is used at the time of flushing, the compatibility between the resins decreases and the desired static It is easy for characteristics to not be obtained.

The water-soluble inorganic salt (C) used in the present invention
Examples thereof include, but are not limited to, salt, potassium chloride, sodium sulfate and the like.

The water-soluble solvent (D) used in the present invention
The solvent is not particularly limited as long as it is water-soluble. However, a solvent having a high boiling point is preferred from the viewpoint of safety because the temperature rises during salt milling and the solvent is easily evaporated. Since the water-soluble solvent is added for a binder and an effect of preventing crystallization, the amount is preferably in the above range. Examples of the water-soluble solvent (D) used in the present invention include 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, and diethylene glycol monomethyl. Ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-ethoxy-2-propanol, diethylene glycol Propylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, low molecular weight polypropylene glycol, etc. Possible it is. In addition to the above compounds, a dispersant during salt milling,
An additive such as a plasticizer may be used in combination.

The water-soluble inorganic salt (C) used in the present invention has a weight ratio of 2 to 2 with respect to the water-soluble solvent (D).
It is preferably used 20 times, and more preferably used 3 to 10 times. When the amount of the water-soluble inorganic salt (C) is smaller than that of the water-soluble solvent (D), the effect of making the organic pigment (A) finer is small. Conversely, if the amount of the water-soluble solvent (D) is smaller than the amount of the water-soluble inorganic salt (C), the temperature during salt milling tends to increase, and re-agglomeration of fine pigment particles tends to occur.

The preferred particle size of the pigment in the aqueous paste (E) of the treated pigment at the end of the salt milling is such that the average particle size measured by a laser scattering method is 1.0 μm or less, more preferably It is 0.2 μm or less. With such a particle size, clear and sufficient color reproducibility and color developability can be obtained. Particularly, when a full-color image is formed on a transparent substrate such as an OHP sheet, it has a remarkable transparency for electrostatic charge development. A toner is obtained.

The resin-coated pigment (G) in the present invention can be obtained, for example, as follows. The aqueous paste (E) of the treated pigment is transferred to a mixing and dispersing machine such as a kneader or a supermixer, and a resin (F) which is a solid at room temperature and other various additives are added as necessary, followed by mixing and stirring. At this time, heating may be performed if necessary. About 10 minutes ~
In 20 minutes, the pigment content is transferred to the resin. The separated water is removed by decantation, and the remaining kneaded material is removed with water using two or three rolls as necessary to obtain a resin-coated pigment (G) (a pigment-rich chip). Good.

As the resin (F) which is a solid at room temperature, that is, a resin that can be used for flashing, it can be widely used, including known resins. In consideration of image transparency, a colorless and transparent resin is more preferable. For example, all known resins such as styrene-acrylic and polyester resins such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and mixtures thereof can be used. In addition, polyethylene, polypropylene, polystyrene, styrene-butadiene copolymer, chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic resin, phenol resin, rosin-modified phenol resin, epoxy resin, ionomer resin, polyurethane resin, Silicone resin, rosin / ester, rosin and the like can be mentioned. The production method of any resin is not particularly limited.

The toner base particles of the present invention can be obtained according to a conventional method. That is, the binder resin (H) and, if necessary, other charge control agents and additives are added to the resin-coated pigment (G) and premixed by a Henschel mixer or the like. Thereafter, dilution and melt kneading are performed by an extruder or the like. Next, after cooling, it is coarsely pulverized by a hammer mill or the like and finely pulverized by a jet mill or the like. Thereafter, the particles are classified by an air classifier or the like to obtain a classified product having a predetermined particle size distribution with an average particle size of about 5 to 20 μm, that is, toner base particles.

The binder resin (H), that is, a resin that can be used for melt-kneading after flushing, can be widely used, including known resins. In consideration of image transparency, a colorless and transparent resin is more preferable. The same type of resin as the resin (F) which is a solid at room temperature can be used, but the binder resin (H) does not necessarily have to match the resin (F).

It is also preferable to add a charge control agent to the toner base particles of the present invention. When the toner base particles are black, examples of the charge control agent include a nigrosine dye, a triphenylmethane dye, a rhodamine dye, an alkoxyamine, a chromium-containing metal complex, a molybdate chelate pigment, a quaternary ammonium salt, and an alkyl. Organic metal complexes such as amides, metal complexes of alkyl-substituted salicylic acids (eg, chromium, aluminum, or zinc complexes of di-tert-butylsalicylic acid) and the like can be used. Further, when the toner base particles are other than black, a colorless or light-colored charge control agent that does not affect the color tone of the image is preferable. Or a zinc complex, etc.).

The toner base particles of the present invention preferably contain various particles as external additives, such as a fluidity improver and a cleaning aid. Any known external additives can be used. For example, 0.01 to 0.5 μm silica, alumina, metal oxides such as titanium oxide, silicon carbide, abrasives such as tungsten carbide, zinc stearate,
Lubricants such as fatty acid metal salts such as aluminum stearate,
In addition, polytetrafluoroethylene of 1 to 50 μm, polyvinylidene fluoride, polymethyl methacrylate,
It is preferable to add fine powder such as polystyrene and silicone. It is also preferable to add an external additive obtained by variously surface-treating these mixtures and further, these fine powders.

The developer of the present invention is a mixture of the toner and the carrier, and can be obtained by a conventionally known method, and is not particularly limited. As the carrier used for the developer according to the present invention, all known carriers can be used. In general, carriers constituting a two-component developer are roughly classified into conductive carriers and insulating carriers. Normally, oxidized or unoxidized iron powder is used as the conductive carrier. A typical example of the insulating carrier is a carrier in which the surface of a carrier core material particle generally made of a ferromagnetic material is uniformly coated with an insulating resin. Examples of the core material of the carrier include particles of iron oxide (magnetite), reduced iron, copper, ferrite, nickel, cobalt, and the like, and alloys of these and zinc, aluminum, and the like. Acrylic resin as coating resin,
Any of known materials such as an epoxy resin, a silicone resin, a urethane resin, a polyacetal resin, a polyamide resin, a polycarbonate resin, a phenol resin, a vinyl acetate resin, a cellulose resin, a polyolefin resin, a fluororesin, and an amino resin may be used. The carrier preferably has a particle size of about 20 to 200 μm. Generally, the developer preferably contains 1 to 30% of toner.

[0043]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. However, this does not limit the embodiment of the present invention at all. In Examples and Comparative Examples, parts and% indicate parts by weight and% by weight, respectively.

Example 1 Crude copper phthalocyanine (Lionol Blue SL, manufactured by Toyo Ink): 250 parts, sodium chloride: 2500 parts, unsaturated polyester resin:
90 parts and 160 parts of polyethylene glycol 300 (manufactured by Tokyo Kasei) were charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, stirred for about 1 hour with a high-speed mixer while heating to about 80 ° C. to form a slurry, and then filtered and washed five times to repeat sodium chloride and solvent. , An aqueous paste having a solid content of 50% (a pigment dispersion treated with a polyester resin) was obtained.

Next, the process proceeds to the flushing step. The aqueous paste (solid content 50%) 100.0 parts Unsaturated polyester resin, resin (F) at room temperature solid 25.0 parts Methanol 0.5 part In about 10 minutes, the pigment content was transferred to the resin (flushing). After removing the separated water and solvent from the kneader, the remaining kneaded material was passed five times with a heating-type two rolls to obtain a high-concentration pigment chip, that is, a resin-coated pigment (G).

Unsaturated polyester resin, binder resin (H) 100.0 parts High-concentration pigment chip 5.0 parts Negative charge control agent 4.0 parts Next, the composition is melt-kneaded with an extruder, After cooling, the resultant was coarsely pulverized by a hammer mill and further finely pulverized by a jet mill to obtain a toner having an average particle diameter of 10 μm.

6 parts of the resulting toner was added to 100 parts of ferrite, and mixed with a ball mill to obtain a developer. Using this developer, a commercially available full-color copying machine (CLC
350, manufactured by Canon Inc.) and evaluated.

Example 2 An aqueous paste was obtained in the same manner as in Example 1, except that a yellow pigment (Lionol yellow ester resin) was used instead of the crude copper phthalocyanine of Example 1. In the subsequent steps, a toner was prepared in the same manner as in Example 1. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Example 3 Crude copper phthalocyanine (Lionol Blue SL, manufactured by Toyo Ink): 250 parts, sodium chloride: 900 parts, styrene-acrylic resin: 1
00 parts and diethylene glycol (manufactured by Tokyo Chemical Industry): 16
0 parts were charged into the kneader described in Example 1 and kneaded for 2 hours. This was treated in the same manner as in Example 1 to obtain an acrylic-based aqueous paste having a solid content of 50%. The subsequent steps were the same as in Example 1, except that styrene-acryl was used as the resin to prepare a toner. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Example 4 Instead of the crude copper phthalocyanine of Example 1, 280 parts of a quinacridone pigment (Lionol Red 6B4206-P, manufactured by Toyo Ink Co., Ltd.) was used and treated in the same manner as in Example 1 to obtain a solid. Aqueous paste of 50% for acrylic treatment was obtained. Subsequent steps are also described in Example 1.
In the same manner as in Example 3, except that the same styrene-acrylic resin as in Example 3 was used to prepare a toner. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

The following Comparative Examples 1 to 4 show examples in which only salting was not performed and only flushing was performed. [Comparative Example 1] Crude copper phthalocyanine (Lionol Blue SL, manufactured by Toyo Ink Mfg., Solid content 50%) 100.0 parts Unsaturated polyester resin (same as in Example 1) 25.0 parts Methanol 0.5 part The above raw materials Was heated and mixed in a kneader at 100 ° C., and the pigment was transferred to the resin (flushing) in about 10 minutes. After removing the separated water and solvent from the kneader, the remaining kneaded material was passed five times with a heated two-roll mill to obtain a pigment-rich chip.

Unsaturated polyester resin (same as in Example 1) 100.0 parts High-concentration pigment chip 5.0 parts Negative charge control agent 4.0 parts Next, the composition was melt-kneaded with an extruder, After cooling, the resultant was coarsely pulverized by a hammer mill and further finely pulverized by a jet mill to obtain a toner having an average particle diameter of 10 μm.

6 parts of the resulting toner was added to 100 parts of ferrite, and mixed with a ball mill to obtain a developer. Using this developer, a commercially available full-color copying machine (CLC
350, manufactured by Canon Inc.) and evaluated.

Comparative Example 2 Instead of the crude copper phthalocyanine of Comparative Example 1, a crude yellow pigment (Lionol Yellow G) was used.
R, manufactured by Toyo Ink Manufacturing Co., Ltd., solid content 50%), and using the same resin (unsaturated polyester resin) as in Example 1,
A pigment dispersion was obtained in the same manner as in Comparative Example 1. In the subsequent steps, a toner was prepared in the same manner as in Comparative Example 1. Comparative Example 1
An image was formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Comparative Example 3 Crude copper phthalocyanine (Lionol Blue SL, manufactured by Toyo Ink, solid content 50%)
Using the same resin (styrene-acrylic resin) as in Example 3, a pigment dispersion was obtained in the same manner as in Comparative Example 1. In the subsequent steps, a toner was prepared in the same manner as in Example 1. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Comparative Example 4 Instead of the crude copper phthalocyanine of Comparative Example 1, a quinacridone pigment (Lionol Red 6B4206-P, manufactured by Toyo Ink, solid content 50%)
Using the same resin (styrene-acrylic resin) as in Example 3, a pigment dispersion was obtained in the same manner as in Comparative Example 1. In the subsequent steps, a toner was prepared in the same manner as in Comparative Example 1. Further, an image was formed using a commercially available full-color copying machine in the same manner as in Comparative Example 1, and evaluated.

The following Comparative Examples 5 to 8 show examples of toners formed by a usual method. That is, neither salt milling nor flushing is performed. [Comparative Example 5] Unsaturated polyester resin 100.0 parts Blue pigment (Lionol Blue SL, manufactured by Toyo Ink Mfg.) 3.0 parts (Note: pigment formed through normal drying step) Negative charge control agent 4 Then, after mixing the above composition with a super mixer,
The mixture was melted and kneaded with an extruder, and then a toner was prepared in the same manner as in Example 1. Further, a developer was prepared, and an image was formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Comparative Example 6 A yellow pigment (Lionol Yellow GR, manufactured by Toyo Ink) was used in place of the blue pigment (Lionol Blue SL, manufactured by Toyo Ink) of Comparative Example 1, and the same as in Example 1 was used. Resin (unsaturated polyester resin)
To obtain a pigment dispersion in the same manner as in Comparative Example 5.
In the subsequent steps, a toner was prepared in the same manner as in Comparative Example 5.
Further, an image was formed using a commercially available full-color copying machine in the same manner as in Comparative Example 1, and evaluated.

Comparative Example 7 A pigment was dispersed in the same manner as in Comparative Example 5 using a blue pigment (Lionol Blue SL, manufactured by Toyo Ink Manufacturing Co., Ltd.) and the same resin as in Example 3 (styrene-acrylic resin). I got a body. In the subsequent steps, a toner was prepared in the same manner as in Example 1. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

Comparative Example 8 A quinacridone pigment (Lionol Red 6B4206-P, manufactured by Toyo Ink Manufacturing Co., Ltd.) was used, and the same resin (styrene-acrylic resin) as in Example 3 was used. A pigment dispersion was obtained. In the subsequent steps, a toner was prepared in the same manner as in Example 1. Further, images were formed using a commercially available full-color copying machine in the same manner as in Example 1 and evaluated.

In Examples 1 to 4, as described in the present invention, salt milling is performed with a synthetic resin interposed, and a toner is formed through a flushing process. was gotten. Also, a clear image was obtained for the intermediate colors using the toners of the individual colors. When an image was formed on the OHP sheet, clear and remarkable transparency comparable to that of a dye was obtained. In addition, the obtained toner was melted by hot pressing to form a uniform thin layer on a glass plate, and the dispersion state was observed with an optical microscope. It was confirmed that the dispersion state was very good without aggregation. done.

In Comparative Examples 1 to 4, salt milling was not performed.
This is an example in which only flushing is performed. The image had a high saturation and a clear image was obtained. Also, a clear image was obtained for the intermediate colors using the toners of the individual colors. Although considerable transparency was obtained when an image was formed on the OHP sheet, it was inferior to Examples 1 to 4, and the effect of performing salt milling with a synthetic resin interposed was confirmed.

In Comparative Examples 5 to 8, the pigments and resins used in Examples 1 to 4 and Comparative Examples 1 to 4 were used, and toners were formed in the same combination by a usual production method. That is, at that time, neither salt milling nor flushing was performed. These Comparative Examples 5 to 8 did not provide clear and sufficient color reproducibility and color developability, and were compared with Examples using the same pigment. Examples 1 to 4 and Comparative Examples 1 to 4 The difference was clear. Further, when the images are compared with, for example, Example 1, Comparative Example 1, and Comparative Example 5 using the same pigment, it can be seen that the images decrease in this order.

[0064]

According to the present invention, the particle size of the pigment in the toner is small, clear and sufficient color reproducibility and color developability are obtained, and particularly when an image is formed on a transparent substrate such as an OHP sheet. As a result, a toner for developing an electrostatic image capable of obtaining a clear and remarkable transparency comparable to that of a dye and a developer containing the toner and a carrier were obtained. When the dispersion state of the pigment in the toner was observed with an optical microscope, it was confirmed that the dispersion state was very good without aggregation.

Claims (6)

[Claims] 1. An organic pigment (A), a synthetic resin (B) which is solid and water-insoluble at room temperature, a water-soluble inorganic salt (C), and at least one synthetic resin (B) which is solid and water-insoluble at room temperature. An aqueous paste (E) of a treated pigment obtained by mechanically kneading a mixture comprising at least four components of a partially soluble water-soluble solvent (D), and then removing (C) and (D) by washing with water; An electrostatic image development characterized by heating and kneading a solid resin (F) and then kneading a resin-coated pigment (G) obtained by removing water and a binder resin (H). For toner mother particles. 2. The electrostatic image development according to claim 1, wherein the organic pigment (A) is one selected from the group consisting of quinacridone-based organic pigments, phthalocyanine-based organic pigments, and azo-based organic pigments. For toner mother particles. 3. An organic pigment (A) based on 100 parts by weight,
1 to 10 water-insoluble synthetic resin (B) which is solid at room temperature
3. The toner base particles for developing an electrostatic image according to claim 1, wherein 0 parts by weight are used. 4. The electrostatic charge according to claim 1, wherein the weight ratio of the water-soluble inorganic salt (C) to the water-soluble solvent (D) is 2 to 20 times. Toner base particles for image development. 5. An electrostatic image developing toner comprising a mixture of an electrostatic image developing toner base particle according to claim 1 and an external additive. 6. A developer comprising a mixture of the toner for developing an electrostatic charge image according to claim 5 and a carrier.