JP2537503B2 - Toner for electrostatic image development - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like, and a method for producing the toner.

2. Description of the Related Art Conventionally widely used toners are obtained by dry blending a styrene / acrylate copolymer powder obtained by suspension polymerization with a colorant such as carbon black, an optional charge control agent and / or a magnetic material. It has been produced by melt-kneading with a post-extruder or the like, and then crushing and classifying (see Japanese Patent Laid-Open No. 51-23354).

However, the conventional toner obtained by the melt-kneading-pulverization method as described above has a limitation in controlling the particle size of the toner, and a toner having an average particle size of substantially 10 μm or less, particularly 8 μm or less, and particularly 5 μm or less. Although it is difficult to manufacture the toner with high yield, it is difficult to avoid the drawbacks that the resolution is low and fog occurs when it is used as a developer.

OBJECT OF THE INVENTION The present invention greatly improves the above-mentioned drawbacks of the toners that have been widely used in the past, and provides a toner which is cheaper than the toners of the conventional methods by using a novel manufacturing method. The purpose is.

Features of the present invention The toner for developing an electrostatic image of the present invention comprises a polymer having an acidic polar group or a basic polar group (hereinafter referred to as "polymer having a polar group"), preferably a polymer having an acidic polar group. A toner for developing an electrostatic charge image, comprising associated particles of secondary particles containing primary particles, colorant particles, and an optional charge control agent.

The primary particles of the polymer having a polar group used in the present invention are particles of a thermoplastic polymer having an average particle diameter of 0.05 to 0.5μ, preferably 0.1 to 0.3μ, and are generally suitably obtained by an emulsion polymerization method. To be The secondary particles constituting the above-mentioned associated particles, which are the toner of the present invention, are 0.01 to 0.5, preferably
The colorant particles having an average particle diameter of 0.03 to 0.1μ and the primary particles of the polymer having a polar group have ionic bonds, hydrogen bonds, metal coordination bonds, weak acid-weak group bonds, or van der Waals forces, etc. The particles are aggregated by the binding force and generally have an average particle size of 0.5 to 5μ, preferably 1 to 4μ. FIG. 1 is a scanning electron microscope photograph at a magnification of 1,000 times showing an example of secondary particles produced in the toner manufacturing process of the present invention.

The associated particles of the present invention are indefinite particles produced by agglomeration of the above secondary particles, and the average particle size thereof is generally 3 to 25.
μ, preferably 5 to 15 μ, and most preferably 5 to 13 μ.
FIG. 2 is a scanning electron micrograph at a magnification of 1,000 times showing an example of associated particles which are the toner of the present invention.

In a preferred embodiment of the present invention, at least a part of the contact portion between the secondary particles constituting the above-mentioned associated particles, preferably the majority of the contact portion between the secondary particles, the associated particles are film-fused. Used. FIG. 3 is a scanning electron micrograph (magnification: 1000) of the associated particles in which at least a part of the contact portion between the secondary particles of the present invention is film-fused.

The associated particles, which are the toner of the present invention, have a polar group-containing polymer in an amount of 20 to 20 per the total amount of the polymer having a polar group and the colorant.
99.9% by weight, preferably 30-98% by weight, most preferably
40-95% by weight and 80-0.1% by weight of colorant, preferably 7
The content is 0 to 2% by weight, most preferably 60 to 5% by weight.

Preferred examples of the polymer having a polar group used in the present invention are copolymers of styrenes, alkyl (meth) acrylates and comonomers having an acidic polar group or a basic polar group (hereinafter referred to as "comonomer having a polar group"). Is.

Preferred examples of such copolymers include styrenes based on the sum of (a), (a) and (b).
90 to 20% by weight, preferably 70 to 30% by weight, 10 to 80% by weight, preferably 30 to 70% by weight of alkyl (meth) acrylate based on the sum of (b), (a) and (b)
%, And a copolymer containing 0.05 to 30 parts by weight, preferably 1 to 20 parts by weight of a comonomer having a polar group, when the total of (c), (a) and (b) is 100 parts by weight. is there. In addition to the monomers (a), (b) and (c), the above copolymer may optionally contain other comonomers that can be copolymerized to the extent that the performance of the toner of the present invention is not impaired. .

Examples of (a) styrenes include styrene and o
-Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,
4-dimethylstyrene, pn-butylstyrene, pt
ert-butyl styrene, pn-hexyl styrene, p
-N-octyl styrene, pn-nonyl styrene, p
-N-decyl styrene, pn-dodecyl styrene, p
-Methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-chloromethylstyrene and the like can be mentioned, with styrene being particularly preferred.

Examples of the (b) alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, α
-Methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, Examples thereof include 2-ethylhexyl methacrylate and stearyl methacrylate. Among them, (meth) acrylic acid ester of aliphatic alcohol having 1 to 12 carbon atoms, preferably 3 to 8 carbon atoms, and particularly preferably 4 is used. .

As the monomer having an acidic polar group of (c) above,
Examples include (i) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (ii) an α, β-ethylenically unsaturated compound having a sulfone group (—SO ₃ H).

Examples of the α, β-ethylenically unsaturated compound having a —COO group (i) include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, and maleic acid. Examples thereof include acid monooctyl ester and metal salts thereof such as NaZn.

Examples of the α, β-ethylenically unsaturated compound having a —SO ₃ H group in (ii) include sulfonated styrene, its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate,
The Na salt etc. can be mentioned.

Further, as the comonomer having a basic polar group of (C), (i) an aliphatic alcohol having an amine group or a quaternary ammonium group and having 1 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and particularly preferably 2 (Meth) acrylic acid ester, (ii) (meth) acrylic acid amide or (meth) acrylic acid amide mono- or di-substituted with an alkyl group having 1 to 18 carbon atoms on N, (iii) N Examples thereof include a vinyl compound substituted with a heterocyclic group having as a ring member and (iv) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Above all,
The (meth) acrylic acid ester of an aliphatic alcohol having an amine group or a quaternary ammonium group of (i) is preferable as a comonomer having a basic group.

Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or a quaternary ammonium group of (i) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate,
Examples thereof include quaternary ammonium salts of the above-mentioned 4 compounds, 3-dimethylaminophenyl acrylate, and 2-hydroxy-3-methacryloxypropyl trimethylammonium salt.

(Ii) (Meth) acrylic amide or (meth) acrylic amide optionally mono- or di-alkyl substituted on N includes acrylamide, N-butyl acrylamide, N, N-dibutyl acrylamide, piperidyl acrylamide, Methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like can be mentioned.

Examples of the vinyl compound (iii) substituted with a heterocyclic group having N as a ring member include vinyl pyridine, vinyl pyrrolidone, vinyl N-methylpyridinium chloride, vinyl N-ethylpyridinium chloride and the like.

Examples of N, N-diallylalkylamine of (iv) include N, N-diallylmethylammonium chloride, N, N-
Examples include diallylethylammonium chloride.

The glass transition point of the polymer having a polar group used in the present invention is −90 to 100 ° C., preferably −30 to 80 ° C., most preferably −10 to 60 ° C., and its gelation degree is Represented by insoluble matter during Soxhlet extraction under acetone reflux.
It is 0 to 99.9% by weight, preferably 1 to 30% by weight. If the glass transition point is higher than 100 ° C and is too high, the low-temperature fixability tends to be poor, which is not preferable, and if it is lower than -90 ° C, the powder fluidity of the toner tends to be low. It is not preferable. On the other hand, if the degree of gelation exceeds 50% by weight and is too high, the low temperature fixability tends to deteriorate, which is not preferable.

In the present specification, the term "colorant" is used to mean a coloring additive that gives the developer a color required for an electrostatic image developer, and a magnetic substance such as magnetite or a nigrosine dye. An additive that imparts a property other than a colorant such as a magnetic property or a charge controllability to the developer, such as a charge control agent, is included in the “colorant” if it imparts the desired colorability to the developer. It is a thing.

The colorant used in the present invention, an inorganic pigment or,
Organic pigments and organic dyes, preferably inorganic pigments or organic pigments are used, but one or more pigments or / and one or more dyes may be used in combination as required. Examples of such inorganic pigments include (a) metal powder pigments, (b) metal oxide pigments, (c) carbon pigments, (d) sulfide pigments, (e) chromate pigments, (F) Preference is given to ferrocyanide salt pigments and the like.

Examples of such (a) metal powder pigments include zinc powder, iron powder, and copper powder.

(B) Examples of metal oxide pigments include magnetite, ferrite, red iron oxide, titanium oxide, zinc white, silica, chromium oxide, ultramarine, cobalt blue, cerulean blue, mineral violet, trilead tetraoxide, and the like. To be

(C) Examples of carbon-based pigments include carbon black, thermatomic carbon, lamp black, and fannes black.

(D) Examples of sulfide pigments include zinc sulfide, cadmium red, selenium red, mercury sulfide, and cadmium yellow.

(E) Examples of chromate pigments include molybdenum red, barium yellow, strontium yellow, and chrome yellow.

(F) Examples of ferrocyanide compound-based pigments include miloli blue.

Moreover, the following can be illustrated as said organic pigment.

(A) Azo pigments: Hansa Yellow G, Benzidine Yellow, Benzidine Orange, Permanent Red 4R, Pyrazolone Red,
Resol red, brilliant scarlet G, bon maroon light, etc.

(B) Acid dyes and basic dyes, orange II, acid orange R, eoxin, quinoline yellow, tartrazine yellow, acid green, pekotsk blue, alkali blue and other dyes were precipitated with a precipitant. thing. Rhodamine, magenta, malachite green, methyl violet, Victoria blue and other dyes precipitated with tannic acid, tartar, PTA, PMA, PTMA, etc.

(C) Mordant dye-based pigments Metal salts of hydroxyanthraquinones, alizarin murder lake, etc.

(D) Phthalocyanine pigments such as phthalocyanine blue and sulfonated copper phthalocyanine.

(E) Quinacridone pigments and dioxane pigments Quinacridone red, quinacridone violet, carbazole dioxazine violet, and the like.

(D) Other organic fluorescent pigments, aniline black, etc.

Further, as the organic dye, a nigrosine dye or an aniline dye is used.

As described above, the toner of the present invention contains a charge control agent, a magnetic material and the like, if necessary. Examples of such a charge control agent include nigrosine-based electron-donating dyes for positive use, other metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salts, alkylamides, chelates, pigments, and fluorine treatment activity. Agents,
For minus, electron-accepting organic complexes, other chlorinated paraffins, chlorinated polyesters, polyesters having excess acid groups, sulfonylamines of copper phthalocyanine and the like can be exemplified.

Further, the toner of the present invention can be used together with an additive such as a fluidizing agent if necessary, and as such fluidizing agent, fine powder of hydrophobic silica, titanium oxide, aluminum oxide or the like can be exemplified, and toner 100 The amount is 0.01 to 5 parts by weight, preferably 0.1 to 1 part by weight.

The preferred method for producing the toner of the present invention is as follows. Emulsion of a polymer having an acidic polar group or a basic polar group obtained by emulsion polymerization is added and mixed with a required amount of a colorant powder and an optional charge control agent to uniformly disperse it for 0.5 to 4 hours, preferably 1 to When stirring is continued for 3 hours, the primary particles of the polymer having a polar group and the colorant particles gradually aggregate to grow into secondary particles having an average particle size of 0.5 to 5 μ as shown in the photograph of FIG. . When such a dispersion is further stirred as it is for 0.5 to 3 hours, preferably 1 to 2 hours, the secondary particles are further aggregated to give an average particle diameter of 5 to 25 μ as shown in the photograph of FIG. Propagate to the associated particles. In the most preferable method for producing the toner of the present invention, the dispersion liquid thus produced is further added to a glass transition point of the polymer having a polar group to a temperature 20 ° C. higher than the glass transition point by 1 to 6 ° C.
When stirring is continued for a time, preferably 2 to 4 hours, as shown in the photograph of FIG. 3, associated particles in which at least a part of the contact portion between the secondary particles are film-fused are formed. Since such associated particles have a film-forming fusion between the secondary particles, they are hardly disintegrated during storage, transportation, production of the developer, etc., and thus are particularly suitable as a developer for developing an electrostatic image. It is suitable.

The toner of the present invention is mixed with carriers such as iron and glass beads to be a developer, but when the toner itself already contains ferrite or the like as a colorant, the ferrite or the like also functions as the carrier. Therefore, in that case, the toner can be used as a developer as it is. As the carrier, iron powder having a negative triboelectrification characteristic by resin coating, preferably fluorine resin coating, is particularly suitable.

EFFECTS OF THE INVENTION The toner of the present invention has a relatively narrow particle size distribution and a relatively small average particle size. Therefore, when it is used as an electrostatic image developer, the resolution is remarkably improved and the occurrence of fogging is almost eliminated. It has an excellent effect that it does not exist, and further that the manufacturing method that does not require pulverization classification is simpler than the conventional method and the yield of necessary toner particles is high, so that it is also excellent in economic efficiency It is a thing.

The present invention will be specifically described below with reference to examples. In addition, unless otherwise specified, the quantities are indicated by weight.

Example 1 Preparation of acidic polar group-containing polymerized resin Styrene monomer (ST) 60 parts Butyl acrylate (BA) 40 parts Acrylic acid (AA) 8 parts Water of the above monomer mixture 100 parts Nonionic emulsifier 1 part (Emulgen 950) anion 1.5 parts of emulsifier (Neogen R) 0.5 part of potassium persulfate was added to an aqueous solution mixture, and the mixture was polymerized at 70 ° C. for 8 hours with stirring to obtain an emulsion containing acidic polar group having a solid content of 50%.

Preparation of toner (1) Resin containing acidic polar group Emulsion 120 parts Magnetite 40 parts Nigrosine dye 5 parts (Bontron N-04) Carbon black 5 parts (diamond # 100) water 380 parts While stirring with stirring the above mixture. About 30 ℃
Hold for 2 hours. Then, the mixture was further heated to 70 ° C. with stirring and held for 3 hours. During this time, observing with a microscope, the complex between the resin particles and the magnetite particles was about 10μ.
Was confirmed to grow. After cooling, the obtained liquid dispersion was filtered with a Buchner filter, washed with water, and vacuum dried at 50 ° C. for 10 hours.

To 100 parts by weight of the toner thus obtained, 0.5 parts by weight of silica (Aerosil R972 manufactured by Nippon Aerosil Co., Ltd.) as a fluidizing agent was added and mixed to prepare a test developer.

The Tg of the above polymer used in this toner was 45 ° C., the degree of gelation was 5%, the softening point was 148 ° C., and the average particle size of the toner was 12 μ.

When the above developer was put into a commercially available copying machine (NP-270Z manufactured by Canon Inc.) and copying was performed, a copy image having high density and less fog was obtained. The results are shown in Table-2.

Examples 2 to 7 The same operation as in Example 1 was repeated using the monomer composition shown in Table 1. Table 2 shows the results. Table-1
The meanings of the abbreviations used in Step 1 are shown below.

2EHA; 2-ethylhexyl acrylate MAA; methacrylic acid MBM; monobutyl maleate BQA; 2-hydroxypropyl-N, N, N-trimethylammonium chloride acrylate DMAA; dimethylaminoethyl acrylate LMA; lauryl methacrylate VP; vinylpyridine DMPC; N, N-Diallylmethylammonium chloride Example 8 After preparing an acidic polar group-containing resin emulsion similar to that in Example 1, the following operations were performed during toner preparation.

Preparation of Toner (2) Acid Polar Group-Containing Resin of Example 1 184 parts Chromium dye (Bontron E-81) 1 part Carbon black (Regal 330R) 7 parts Water 307 parts The above mixture was treated in the same manner as in Example 1. Then, the test toner was prepared. The polymer obtained has a Tg of 43 ° C., a gelation degree of 590, a softening point of 147 ° C., and an average particle diameter of the toner is 10.5 μm.
Met. When this toner was put in a commercially available copying machine (Toshiba made Rhodry BD-4140) and copying was performed, a copy image having high density and less fog was obtained. Table 2 shows the results.

Examples 9 to 11 The same operation as in Example 8 was repeated using the monomer composition shown in Table 1. Table 2 shows the results.

Example 12 During the association particle formation reaction in Example 1, when the temperature was kept at 70 ° C. for 2 hours instead of 70 ° C. for 2 hours, particle growth was controlled and a toner having an average particle size of 5 μm was obtained at a yield of 60%. Was obtained. When a copying test was carried out using this toner, an image having very good resolution, high density and little fog was obtained.

Comparative Example 1 As shown in Table 1, when a resin emulsion prepared by polymerizing without adding AA which is an acidic elementary polar group monomer in the resin monomer composition of Example 1 was used, there was no growth of associated particles,
No test toner was obtained.

Comparative Example 2 The resin emulsion obtained in Example 1 was sprayed with a spray drier (manufactured by Ashiza Vanillo atomizer, Mobile Miner) at an inlet temperature of 120 ° C., an outlet temperature of 90 ° C., and a supply amount of 1.5 l / mi.
n, dried under the operating conditions of atomizer 3 × 10 ⁴ rpm,
A resin was obtained. 60 parts of this resin, 40 parts of magnetite, 5 parts of nigrosine dye (Bontron N-04) and 5 parts of carbon black (diamond black # 100) were melt-kneaded and pulverized to obtain a toner having an average particle size of 5 μm. The yield at this time was 35%.

To 100 parts by weight of the obtained toner, 0.5 parts by weight of silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) was added and mixed as a fluidizing agent to prepare a test developer.

This developer had very poor fluidity. When a copying test similar to that in Example 1 was conducted using this developer, an image with very large fog was obtained.

Comparative Example 3 The same operation as in Comparative Example 2 was carried out to obtain a resin composition as shown in Table 1. Melt kneading and pulverization were carried out in the same composition as in Comparative Example 2 to obtain a yield of 55% and an average particle size of 12.0 μm. Toner was obtained. A similar copying test was conducted using this toner. The results are shown in Table-2.
Shown in

Duplicate image resolution evaluation method Duplicate the data quat company test pattern AR-4,
The number of lines per 1 mm was visually confirmed to evaluate the resolution. In this evaluation method, with the resin composition of Table-1, it can be judged that the resolution of 6.3 or more is good, and the resolution of 3.6 or less is bad.

Copy image fogging evaluation method: Using a CM-53P reflectometer made by Murakami Color Laboratory Co., Ltd., the reflectance of the blank paper before copying and the reflectance of the non-character portion after copying were compared at an optical angle of 45 °, and the reflectance was compared. The fog density (%) was defined as a ratio. It can be judged that the fog density is 0.7 or less and the fog is good, and that the fog density is 1.0 or more is bad.

[Brief description of drawings]

FIG. 1 is a drawing substitute photograph of an electron microscope photograph showing a particle structure of secondary particles at the time of producing the toner of the present invention, and FIG. 2 is a drawing substitute photograph of an electron microscope photograph showing a particle structure of associated particles of the toner of the present invention. FIG. 3 is a drawing-substituting photograph of an electron micrograph showing the particle structure of associated particles in which at least a part of the contact portion between secondary particles is film-fused.

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Claims (4)

(57) [Claims] 1. An electrostatic charge image which is an association particle of primary particles and a colorant particle of a polymer having an acidic polar group or a basic polar group, and secondary particles containing an optional charge control agent. Toner for development. 2. The toner according to claim 1, wherein at least a part of the contact portion between the secondary particles is film-fused. 3. A coloring agent and an optional charge control agent are added to a polymer emulsion, the mixture is heated at 20 to 45 ° C. for 1 to 3 hours with stirring, and then the glass transition point to the glass transition point of the polymer is 20.
The primary particles and the colorant particles of a polymer having an acidic polar group or a basic polar group, characterized in that the associated particles produced by heating to a high temperature of 1 ° C for 1 to 3 hours with stirring are optionally dried. And a method for producing a toner for developing an electrostatic charge image, which is an associated particle of secondary particles containing an optional charge control agent. 4. A toner for developing an electrostatic charge image, which is (1) an associated particle of primary particles and a colorant particle of a polymer having an acidic polar group or a basic polar group, and secondary particles containing a charge control agent. And (2) a developer for developing an electrostatic charge image, which comprises a carrier.