JP2000081732A - Toner matrix particles, toner and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain electrostatic charge image developing toner matrix particles which ensure clear satisfactory color reproducibility and color forming property when a full-color image is formed and to obtain a toner using the toner matrix particles and a developer. SOLUTION: The toner matrix particles contain a treated pigment and a bonding resin. A soln. prepd. by dissolving an org. pigment and a pigment dispersant of the formula P-[X-Y-Z-N(R1)R2]n in sulfuric acid is put in water, a fine deposit is formed and filtration and washing are repeatedly carried out to obtain the treated pigment. In the formula, P is the residue of an org. dye the residue of a heterocycle or the residue of an arom. polycyclic compd., X is a divalent bonding group consisting of 2-15 atoms selected from S, C, N, O and H, Y is a direct bond,-N(R)-(R is H, 1-18C alkyl or Z-N(R1)R2) or -O-, Z is 1-6C alkylene, R1 and R2 are each 1-18C alkyl or form a heterocycle by combination and (n) is an integer of 1-3.

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-resolution 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 recording medium 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 recording medium.

[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, for example, stable chargeability and good fluidity, as in the case of the most common conventional black toner,
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 a recording medium as described above, if the light transmittance of each toner is insufficient, 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 down secondary particles of the pigment (primary particles are weakly aggregated) into primary particles. With the conventional disperser, 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 refining the primary particles of the pigment,
There is known a method in which a pigment is dissolved in a strong acid such as 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. As another method for improving dispersibility, heat treatment in a solvent such as alcohol is known, 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 the present method, the end point is reached when the mechanical crushing force and the crystal growth reach 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 the inorganic salt is mixed. And a solvent which is washed away with water and dried to obtain a pigment having fine primary particles. However, even with this method, there is a problem that the pigment tends to undergo strong secondary aggregation during drying, and the pigment particle size becomes large.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional method, and provides clear and sufficient color reproducibility 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 toner base particle for developing an electrostatic image capable of obtaining color development, a toner and a developer using the toner base particle.

[0012]

The first invention comprises an organic pigment (A) and a pigment dispersant (B) represented by the following general formula (1).
And a solution in which sulfuric acid is dissolved in sulfuric acid is thrown into water to form fine precipitates, and thereafter, the treated pigment (C) and the binder resin (D) obtained by repeating filtration and washing are contained. These are toner base particles for electrostatic image development. General formula (1) P- [XYZN (R ¹ ) R ² ] _n (where P is an organic dye residue or a heterocyclic residue, or an aromatic polycyclic compound residue, X is a divalent linking group consisting of a chemically rational combination composed of 2 to 15 atoms selected from S, C, N, O and H, Y is a direct bond or-
N (R)-(where R is H or an alkyl group having 1 to 18 carbon atoms or ZN (R ¹ ) R ² ) or -O-, Z is an alkylene group having 1 to 6 carbon atoms, R ¹ , R ² is each independently
An optionally substituted alkyl group having 1 to 18 carbon atoms or an optionally substituted heterocyclic ring which may contain N, O or S together with R ¹ and R ^2, and n represents an integer of 1 to 3, respectively. . )

According to a second aspect of the present invention, a solution in which an organic pigment (A) and a pigment dispersant (B) represented by the general formula (1) are dissolved in sulfuric acid is thrown into continuously flowing water. The toner base particles for developing an electrostatic image according to the first aspect of the present invention.

According to a third aspect of the present invention, the organic pigment (A) is a quinacridone pigment, a phthalocyanine pigment, a benzimidazolone pigment, a diketopyrrolopyrrole pigment, a perinone pigment, an anthraquinone pigment, a dioxazine pigment, perylene. A pigment selected from the group consisting of pigments based on azo pigments, isoindolinone pigments and azo pigments.
Or the toner mother particles for developing an electrostatic image according to the second invention.

According to a fourth 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 third aspects and an external additive. It is.

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

[0017]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a solution in which an organic pigment (A) and a pigment dispersant (B) are dissolved in sulfuric acid is poured into water to form fine precipitates. ), And by using the treated pigment (C) obtained by repeating filtration and washing as a colorant for toner base particles, a solution in which the organic pigment (A) and the pigment dispersant (B) are dissolved in sulfuric acid. Is used in a continuously flowing water to obtain a finer and more clear image than before.

When a solution prepared by dissolving the organic pigment (A) and the pigment dispersant (B) in sulfuric acid is poured into water, the liquid is poured into a continuously flowing water so that the first to last steps of the operation are performed. Since constant conditions are always maintained until the stage, not only fine particles are stably generated, but also particles of constant quality can be obtained. When the liquid in which the organic pigment is dissolved in sulfuric acid is thrown into retained water, the liquid temperature rises sharply due to the heat of dissolution when the sulfuric acid dissolves in water, and the finely divided organic pigment crystals tend to grow. , It is preferable to pour into continuous flowing water.

More specifically, the continuously flowing water used in the present invention means water flowing through a pipe or tube having a water pressure of 0.5 to 4.5 kg / cm ² . In order to add a liquid in which an organic pigment or the like is dissolved in sulfuric acid to the water that is continuously flowing, quantitatively using a water aspirator, or a liquid in which the organic pigment is dissolved in sulfuric acid is 0.5 to It is preferred to pressurize to 4.5 kg / cm ² and to spray water continuously flowing from the capillary.

An aqueous solution in which an organic pigment (A) and a pigment dispersant (B) are dissolved in sulfuric acid is brought into contact with continuously flowing water to precipitate an organic pigment and the like. The material is separated and washed with water, ion-exchanged water or a weakly alkaline aqueous solution such as an aqueous solution of caustic soda or caustic potassium to obtain a paste having a solid content of 10 to 40% by weight. Next, the above pigment is washed with water, dried and pulverized to obtain a treated pigment (C), which is used as a colorant for a toner for developing an electrostatic image.

The particle size of the organic pigment (A) after the completion of the acid paste is preferably 0.2 μm or less, more preferably 0.1 μm or less, based on the average particle size by centrifugal sedimentation.
It is 1 μm or less. It has been found that with such a particle size, when an image is formed, clear and sufficient color reproducibility and color developability are easily obtained.

The organic pigment (A) of the present invention includes quinacridone pigments such as quinacridone red and quinacridone magenta, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, benzimidazolone pigments, diketopyrrolopyrrole pigments, and perinone pigments. Pigments, anthraquinone pigments, dioxazine pigments, perylene pigments such as perylene red and perylene scarlet, isoindolinone pigments, azo pigments, etc. are used, and quinacridone pigments, phthalocyanine pigments, benzimidazolone pigments, It is preferable to use ketopyrrolopyrrole pigments, perinone pigments, anthraquinone pigments, dioxazine pigments, perylene pigments, isoindolinone pigments, and azo pigments. Further, a surface-treated pigment obtained by adding a functional group to the surface of the pigment may be used.

In the present invention, among the toner base particles, in the case of black toner base particles, three color processing pigments of yellow, cyan and red may be obtained, and these three color 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 pigment dispersant (B) represented by the general formula (1)
Prevents the re-agglomeration of pigment particles fined by acid pasting and is effective also in the subsequent dispersing step, and improves transparency, color reproducibility, and color development when an image is formed. In the general formula (1), the organic dye constituting the organic dye residue represented by P includes phthalocyanine, insoluble azo, azo lake, anthraquinone, quinacridone, dioxazine, diketopyrrolopyrrole, and anthrapyrimidine. System, anthanthrone system, indanthrone system, flavanthrone system, perinone system, perylene system, thioindigo system and the like. These dyes can be arbitrarily selected, but those having a hue close to the pigment used are industrially more advantageous. Examples of the heterocyclic ring constituting the heterocyclic residue include, for example, thiophene, furan, xanthene, pyrrole, imidazole, isoindoline, isoindolinone, benzimidazolone, indole, quinoline, carbazole, acridine, acridone, anthraquinone and the like. is there. When P is a heterocyclic ring, the pigment dispersant of the general formula (1) is preferable in terms of versatility, since a pigment that is hardly colored can be obtained.

In the general formula (1), X is S, C, N, O, H
A divalent linking group consisting of a chemically rational combination consisting of 2 to 15 atoms selected from, for _{example, -SO 2 -, - CO -} , - CH 2 -, - O-, -C
OO -, - NH-, or a combination thereof, preferably _{-SO 2 -, - CO -,} - CH 2 -, - CH 2
NHCOCH _2- and the like. When R ¹ and R ² are alkyl groups, lower alkyl groups such as a methyl group, an ethyl group, a propyl group and a butyl group are preferred. These alkyl groups may be branched or substituted up to a maximum of 18 carbon atoms. Further, in some cases, R ¹ and R ² may combine to form a 5- or 6-membered heterocyclic ring containing N, O or S.

In the present invention, the pigment dispersant (B) is in the form of a dry powder, is added to the organic pigment (A), is dissolved together with sulfuric acid, and the solution is poured into water to form fine precipitates. That is, in these steps, the primary particle diameter of the pigment can be made smaller than before, and the pigment dispersant can be more strongly adsorbed on the pigment surface.

The toner base particles of the present invention can be obtained according to a conventional method. That is, a binder resin (D) and, if necessary, other charge control agents and additives are added to the treated pigment (C) and premixed by a Henschel mixer or the like, and then melt-kneaded using an extruder or the like. I do. Then, after cooling, the mixture is roughly pulverized by a hammer mill or the like, finely pulverized by a jet mill or the like, and 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.

As the binder resin (D) for the toner base particles of the present invention, conventionally known binder resins can be widely used, but colorless and transparent resins are more preferable in consideration of image transparency. For example, polystyrene, styrene-acrylate copolymer, styrene-butadiene copolymer, chloride resin, styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, Low molecular weight polypropylene, 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.

As the charge control agent to be incorporated into the toner base particles of the present invention, any known charge control agent, both positively and negatively charged, can be used, but a colorless or light-colored charge control agent which does not affect the color tone of the image is preferable. . For example, an organic metal complex such as a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex, an aluminum complex, or a zinc complex of ditertiary butyl salicylic acid) can be preferably used.

The toner base particles of the present invention can be obtained by adding various particles as external additives as a fluidity improver, a cleaning aid and the like to obtain a toner. Any known external additives can be used. For example, 0.01-0.
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, and other 1 to 50 μm polytetrafluoroethylene; It is preferable to add a fine powder such as polyvinylidene fluoride, polymethyl methacrylate, polystyrene, or silicone. It is also preferable to add an external additive obtained by variously surface-treating these mixtures and these fine powders.

The developer of the present invention is obtained by mixing the above-mentioned toner and carrier, and can be obtained by a conventionally known method, and is not particularly limited. As the carrier used in the developer of 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 carrier core material include particles of iron oxide (magnetite), reduced iron, copper, ferrite, nickel, cobalt, and the like, and alloys thereof with zinc, aluminum, and the like. As the coating resin, acrylic resin, epoxy resin, silicone resin, urethane resin, polyacetal resin, polyamide resin, polycarbonate resin, phenol resin, vinyl acetate resin, cellulose resin, polyolefin resin, fluorine resin, amino resin and other known materials Any one may be used. The particle size of the carrier is 20 to
Those having a thickness of about 200 μm are preferred. Generally, the developer preferably contains 1 to 30% of toner.

[0032]

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. Table 1 shows typical examples of the pigment dispersants a to n used in the examples.

[0033]

[Table 1]

Example 1 Lionol Blue FG-7
330 (Phthalocyanine pigment, manufactured by Toyo Ink Manufacturing Co., Ltd.)
28 parts, 2 parts of compound a as a pigment dispersant, and 300 parts of sulfuric acid
The mixture is weighed and placed in a 1-liter glass beaker, and stirred for 1 hour to be sufficiently dissolved. The entire amount of the dissolved solution was dropped in one minute through an aspirator connected to a water flow set at a gauge pressure of 3.50 kg / cm ² . The precipitate is collected by filtration and adjusted to pH
Washed with water to 7.0, filtered, dried and pulverized, and used as a toner colorant.

The above colorant for toner 3.0 parts Unsaturated polyester resin 100.0 parts Negative charge control agent 3.0 parts Premixing each of the above formulation amounts with a Henschel mixer,
Melt and knead with a twin-screw extruder. After cooling, the resulting mixture is roughly pulverized using a hammer mill and further finely pulverized using a jet mill, and then a colorant-containing fine particle having an average particle diameter of 10.0 μm, that is, toner base particles is obtained using an air classifier. 0.4 parts of titanium oxide fine powder having an average particle size of 0.05 μm is added to 100 parts of the obtained colorant-containing fine particles, and mixed with a Henschel mixer to obtain a cyan toner.

6 parts of the obtained toner was added to 100 parts of ferrite and mixed with a ball mill mixer to obtain a developer. Using this developer, a commercially available full-color copying machine (CLC
350, manufactured by Canon Inc.), clear and sufficient color reproducibility and coloring were obtained. In particular, when an image was formed on an OHP sheet, remarkable improvement in transparency was observed as compared with the conventional case. Also, the obtained toner was melted by hot pressing to form a uniform thin layer on a glass plate, and the dispersion state of the pigment was observed with an optical microscope. Was confirmed.

[Examples 2 to 4] In the same manner as in Example 1 except that Compound a used in Example 1 was replaced with Example 2: Compound b Example 3: Compound c Example 4: Compound d Then, a toner and a developer were obtained, and the image was evaluated. The result was the same as that in Example 1.

Example 5 28 parts of Hostaperm Pink E (a quinacridone pigment, manufactured by Hoechst) instead of Lionol Blue FG-7330 as a pigment and 2 parts of compound e instead of compound a as a pigment dispersant The same processing as in Example 1 was carried out to obtain toner base particles, a toner and a developer, except that the toner was not present, and the image was evaluated. The results were the same as those in Example 1.

[Examples 6 to 8] In the same manner as in Example 1 except that the compound e used in Example 5 was replaced with Example 6: Compound f Example 7: Compound g Example 8: Compound h Then, a toner and a developer were obtained, and the image was evaluated. The result was the same as in Example 5.

Example 9 28 parts of Hansa Brilliant Yellow 5GX02 (monoazo pigment, manufactured by Hoechst) in place of Lionol Blue FG-7330 as a pigment and 2 parts of compound i in place of compound a as a pigment dispersant Except for the above, processing was performed in the same manner as in Example 1 to obtain toner base particles, a toner and a developer, and the image was evaluated.
The result was the same as in Example 1.

Example 10 Compound j according to Example 9
Was used to form toner base particles, a toner and a developer. When an image was evaluated using this developer, the same results as in Example 9 were obtained.

Example 11 Irgazi Yellow 2GL was used in place of Lionol Blue FG-7330 as a pigment.
TE (isoindolinone pigment, Ciba-Geigy) 2
Except for using 8 parts and 2 parts of compound k instead of compound a as a pigment dispersant, the same processing as in Example 1 was performed to obtain toner base particles, a toner and a developer, and the image was evaluated. The result was the same as in Example 1.

Example 12 Toner particles, a toner and a developer were formed using Compound 1 in the same manner as in Example 11. When an image was evaluated using this developer, the same results as in Example 11 were obtained.

Comparative Example 1 The following materials were premixed with a Henschel mixer and melt-kneaded with an extruder. Lionol Blue FG-7330 3.0 parts (Phthalocyanine pigment, manufactured by Toyo Ink Manufacturing Co., Ltd.) Unsaturated polyester resin 100.0 parts Negative charge control agent 3.0 parts After cooling, coarsely pulverized using a hammer mill, Next, after finely pulverizing with a jet mill, the average particle size was 10, 0 with an air classifier.
A colorant-containing fine particle of μm, that is, a toner base particle is obtained. To 100 parts of the coloring agent-containing fine particles, 0 and 4 parts of titanium oxide fine powder having an average particle diameter of 0.05 μm are added and mixed with a Henschel mixer to obtain a toner.

6 parts of the obtained 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.), clear and sufficient color reproducibility and coloring were not obtained. When the images were compared with Example 1 using the same pigment, the difference was obvious. .

[Comparative Examples 2 to 5] Lionol Blue FG-7330 (phthalocyanine pigment,
Comparative Example 2: Hostaperm Pink E (quinacridone pigment, manufactured by Hoechst) instead of Toyo Ink Mfg. Comparative Example 3: Hansa Brilliant Yellow 5GX02 (monoazo pigment, manufactured by Hoechst) Comparative Example 4: Irgazine Yellow 2GLTE (isoindolinone pigment, manufactured by Ciba-Geigy) was treated in the same manner as in Comparative Example 1 except that each was used to obtain a toner and a developer, and the image was evaluated. 1
It was the same result as.

According to the present invention, clear and sufficient color reproducibility,
As a result, a toner base particle, a toner and a developer for developing an electrostatic image capable of obtaining color development were obtained. When the dispersion state of the pigment in the toner mother particles was observed with an optical microscope, it was confirmed that the dispersion state was very good without aggregation.

Claims (5)

[Claims] 1. A solution in which an organic pigment (A) and a pigment dispersant (B) represented by the following general formula (1) are dissolved in sulfuric acid is poured into water to form fine precipitates, and then filtered and washed. And a binder resin (D) obtained by repeating the above process. General formula (1) P- [XYZN (R ¹ ) R ² ] _n (where P is an organic dye residue or a heterocyclic residue, or an aromatic polycyclic compound residue, X is a divalent linking group consisting of a chemically rational combination composed of 2 to 15 atoms selected from S, C, N, O and H, Y is a direct bond or-
N (R)-(where R is H or an alkyl group having 1 to 18 carbon atoms or ZN (R ¹ ) R ² ) or -O-, Z is an alkylene group having 1 to 6 carbon atoms, R ¹ , R ² is each independently
An optionally substituted alkyl group having 1 to 18 carbon atoms or a heterocyclic ring which may contain N, O or S together with R ¹ and R ^2, and n represents an integer of 1 to 3, . ) 2. A method in which a solution in which an organic pigment (A) and a pigment dispersant (B) represented by the general formula (1) are dissolved in sulfuric acid is thrown into continuously flowing water. The toner base particles for developing an electrostatic image according to claim 1. 3. An organic pigment (A) comprising a quinacridone pigment, a phthalocyanine pigment, a benzimidazolone pigment, a diketopyrrolopyrrole pigment, a perinone pigment, an anthraquinone pigment, a dioxazine pigment, a perylene pigment, 3. The toner base particles according to claim 1, wherein the toner base particles are one selected from the group consisting of indolinone pigments and azo pigments. 4. A toner for developing an electrostatic image, comprising a mixture of the toner base particles for developing an electrostatic image according to claim 1 and an external additive. 5. A developer comprising a mixture of the toner for developing an electrostatic charge image according to claim 4 and a carrier.