JPH04318560A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To enhance resolution, sharpness, halftone reproduction performance, cleaning performance, and the like, and to stabilize chargeability against the lapse of time by using specified resin particles as a base material and specifying the surface friction coefficient of the toner. CONSTITUTION:The resin particles to be used as the base material has a ratio of volume average particle diameter (Dv) to number average particlel diameter (Dp) Dv/Dp of 1.00-1.20 and a Dv of 1-10mum and a surface friction coefficient of the toner of <=0.8. It is preferred to control attachment force between the toner particles to <=10gf/cm<2>, when no load is applied to them, and to regulate it to <=30gf/cm<2>, when 70gf/cm<2> load is applied in a packing state, and it is preferred to use, for example, methyl alcohol or the like as a hydrophilic organic liquid to be used for a diluent of a monomer used at the time of forming and growing the resin particles.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to electrophotography, electrostatic recording,
The present invention relates to a dry toner for developing electrostatic images in electrostatic printing and the like.

0002

[Prior Art] As means for developing an electrostatic latent image formed on an electrophotographic photoreceptor or an electrostatic recording medium, there are two methods: a method using a liquid developer (wet development method), and a method using a liquid developer (wet development method). dye,
A method using a toner in which colorants such as pigments and a charge control agent are dispersed as necessary, or a one-component or two-component dry developer in which this toner is mixed with a solid carrier (dry development method). is generally adopted. and,
Although each of these methods has its own advantages and disadvantages, the dry developing method is currently in most use.

Incidentally, in order to provide high image quality and high durability, toner particles are required to have small particle size, sharp particle size distribution, sufficient coloring power, and uniform charging control. That is, reducing the particle size improves qualities such as resolution, sharpness, halftone reproducibility, and photographic reproducibility. Further, a sharp particle size distribution improves particularly halftone reproducibility and photographic reproducibility. Furthermore, the particle size distribution of the toner in the developer does not change even when used for a long time, resulting in stable image quality and a longer lifespan of the developer.

[0004] Toner manufactured by the conventional general manufacturing method of toner, that is, a method in which resin, dye/pigment, and charge control agent are melt-kneaded, and then crushed and classified using a mechanical or air collision type crusher. In particular, when attempting to obtain particles of small size, there are the following drawbacks. That is, (1) production capacity and yield decrease, resulting in higher costs. (2) As the particle size becomes smaller, toner charging characteristics become poorer due to non-uniform dispersion of the charge control agent, and background smearing and toner scattering are more likely to occur. (3) Furthermore, the surface of the small particle diameter toner obtained by pulverization has many protrusions, which tends to cause filming on the carrier, triboelectric charging member, or photoreceptor. (4) When the particle size is reduced, the coloring power of each toner becomes weaker. (5) It is difficult to clean small particle size toner remaining on the photoreceptor. (6) If an attempt is made to obtain a toner with a particularly narrow distribution, the production capacity and yield will be significantly reduced, the cost will increase, and even if classification is repeated, there is a limit to the particle size distribution that can be obtained.

[0005] Therefore, many proposals have been made regarding toners that provide high image quality and high durability and methods for producing the toners. For example, core particles containing colored pigments and charge control agents may be formed by a suspension polymerization method (Japanese Patent Publication No.
14895, Japanese Patent Publication No. 47-51830), this method uses a dispersion stabilizer that adheres to the surface,
It is difficult to remove surfactants, etc., easily causes electrostatic deterioration, and is also susceptible to environmental fluctuations. Furthermore, with this method, it is difficult to stably produce particles with a small particle size and a narrow particle size distribution.

On the other hand, as a method for easily obtaining toner with a small particle size and a narrow particle size distribution, Japanese Patent Application Laid-Open No. 58-106554
No. 61-18965 and No. 61-275766, attempts are made to produce toners with a so-called core-shell structure by attaching and coating colorants and toner characteristic imparting substances onto particles with a narrow particle size distribution. However, toners having such a structure have the disadvantage of poor electrical properties and durability due to the presence of coloring substances and other substances on the surface.

[0007] Furthermore, as another toner manufacturing method, a method has been proposed in which resin particles are immersed in a dye solution and dyed (Japanese Patent Application Laid-Open Nos. 50-46333 and 1999-10363).
No. 1, JP-A-56-154738, JP-A No. 61-2284
No. 58, No. 63-106667, No. 64-90454
Publications, etc.). Although these methods are preferable because they require fewer manufacturing steps, none of them have been sufficiently tested, and it is unclear whether the dye is uniformly colored within the particles, and furthermore, the above-mentioned literature does not Knowledge of the content alone was not enough to put it into practical use. In addition, JP-A-61-22
Publication No. 8458 describes an attempt to color particles by adding dye to particles produced by dispersion polymerization, but according to this method, the polarity of the toner can be controlled by a dispersion stabilizer permanently attached to the particle surface. Therefore, the triboelectric charging property is unstable due to environmental changes, and the stability over time is also poor. Furthermore, in the proposed toner,
In both cases, the problem of poor cleaning due to the reduction in particle size has not been sufficiently solved.

[0008]

[Problems to be Solved by the Invention] In other words, a toner with a small particle size and narrow particle size distribution that has sufficiently stable triboelectric charging properties and good cleaning properties has not yet been found. This is the current situation.

Therefore, an object of the present invention is to provide a small-grain toner with a narrow particle size distribution that solves the above problems, and more specifically, has excellent resolution, sharpness, halftone reproducibility, and photographic reproducibility. It is an object of the present invention to provide a toner having high coloring power, good cleaning properties, high image quality, and high reliability, which has little change in charge amount due to the environment, and has stable chargeability over time.

0010

[Means for Solving the Problems] As a result of intensive studies, the present inventors found that a toner having a specific particle size and surface friction coefficient is suitable for the above purpose, and thus completed the present invention. .

That is, according to the present invention, the volume average particle diameter (D
v) and the number average particle diameter (Dp) [Dv/Dp] is 1.
00 to 1.20 and the volume average particle diameter (Dv) is 1 to 10
Provided is a toner for developing an electrostatic image, which is a toner having resin particles having a diameter of .mu.m as a matrix, and which is characterized in that the surface friction coefficient of the toner is 0.8 or less.

In the electrophotographic process, a cleaning step for removing deposits on the photoreceptor is extremely important for cleaning images. For example, toner remaining due to poor cleaning may adhere to the background area where there is no image during the next development process, so when the second sheet is output, toner remains on the background area and causes "fogging".
A phenomenon occurs. When the inventors of the present invention investigated and studied the toner remaining after cleaning in detail, it was found that most of the residual toner particles were toner with a small particle size, particularly toner with a particle size of 1 μm or less. It is generally known that cleaning performance deteriorates when toner particles have a small particle size, and this will become an important problem when high-resolution images are required in the future.

[0013] The inventor of the present invention conducted intensive research into why toner remains, and as a result, it became clear that the adhesion force acting between toner particles is important. Adhesive forces acting between toners include acid-base interaction force, dispersion force, and liquid crosslinking force. Although it is difficult to separate these components, it is possible to measure the overall adhesion force. When this adhesion force was measured systematically, the following was clarified. That is, (1) The adhesion force of particles with a particle size of 1 μm or less is extremely large;
In particular, as the packing becomes denser, the adhesive force increases significantly. (2) In addition to the effect of particle size, the effect of shape also has a large effect on adhesion. (3) Although additives reduce adhesion, they have the effect of increasing the coefficient of friction, which is disadvantageous for mechanical cleaning methods such as blades. (4) The adhesion of toner containing polyolefin is small.

From the above results, it has become clear that toner with a particle size of 1 μm or less is extremely disadvantageous for cleaning. Further, although toner having a particle size of 10 μm or more has good cleaning properties, the ability to express fine lines in images is reduced, and it is unsatisfactory for use in high-resolution electrophotographic output devices. Therefore, in the present invention, a toner having a uniform particle size distribution and a particle size of 1 to 10 μm, preferably a toner of 5 to 10 μm, is used as a toner that has good cleaning properties and can provide a high-resolution image.

Furthermore, if the friction coefficient of the toner surface is too high, it may not be able to mix sufficiently with the carrier, or transfer defects may occur. According to the research results of the present inventors, it has been found that it is important that the surface friction coefficient is 0.8 or less. That is, if it exceeds 0.8, transfer defects will frequently occur, which is not preferable for solid images. Therefore, the above problem was solved by making the toner of the present invention have a surface friction coefficient of 0.8 or less.

As mentioned above, the adhesion force between toner particles is important for the cleanability of the toner. Therefore, in the toner of the present invention, in addition to the particle size and surface friction coefficient described above, the toner also has a By controlling the adhesion force, cleaning performance can be further improved. In order to control this adhesion force, the shape, particle size distribution, and surface composition of the toner are the governing factors, but among the adhesion force components that act between toners, the adhesion force when the load applied to the toner is zero is 10 gf. /cm2 or less, and 70gf/cm
By setting the adhesion force in the packed state when a load of 2 is applied to be 30 gf/cm2 or less, the cleaning performance can be further improved.

If the adhesion force when the load applied to the toner is zero is 10 gf/cm 2 or more, it is not preferable because the toner tends to remain on the photoreceptor or the fluidity tends to deteriorate. In addition, the adhesion force in the packed state when a load of 70 gf/cm2 is applied is 30 gf.
/cm2 or more, the same thing as above can be said.

The toner of the present invention will be explained in detail below. In the present invention, the ratio [Dv/Dp] of volume average particle diameter (Dv) to number average particle diameter (Dp) is 1.00 to 1.00.
20 and a volume average particle diameter (Dv) of 1 to 10 μm is used as the base particle. To obtain these resin particles, a polymer dispersant that is soluble in the organic liquid is added to a hydrophilic organic liquid, and a polymer that is dissolved in the organic liquid is swollen in the organic liquid. It is preferable to adopt a method in which polymerization is carried out by adding at least one type of vinyl monomer that is either soluble or almost insoluble. According to this method, the ratio of volume average particle diameter (Dv) to number average particle diameter (Dp) is 1.00≦(Dv/Dp)≦1.
Resin particles having a Dv of 1 to 10 μm (hereinafter referred to as resin particles A) can be easily obtained.

[0019] As a method for producing the resin particles A, it is also possible to use a reaction in which a polymer having a narrow particle size distribution, which is smaller than the target particle size, is used in advance and grown in the above-mentioned system. The monomer utilized in the growth reaction may be the same monomer that produced the seed particles or a different monomer, but the polymer must not be soluble in the hydrophilic organic liquid.

Examples of the hydrophilic organic liquid used as a monomer diluent during the formation of the seed particles and the growth reaction of the seed particles include methyl alcohol, ethyl alcohol, denatured ethyl alcohol, isopropyl alcohol,
n-butyl alcohol, isobutyl alcohol, ter
t-butyl alcohol, sec-butyl alcohol, t
Alcohols such as ert-amyl alcohol, 3-pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, glycerin, diethylene glycol; methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene Examples include ether alcohols such as glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. These organic liquids can be used alone or in a mixture of two or more.

[0021] Organic liquids other than alcohols and ether alcohols can be used in combination with the above-mentioned alcohols and ether alcohols under various conditions that do not provide solubility to the polymer particles produced in the organic liquid. By changing the SP value and changing the polymerization conditions, it is possible to suppress the size of the particles produced, the coalescence of seed particles, and the generation of new particles. In this case, organic liquids used in combination include hydrocarbons such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, and xylene; halogenated hydrocarbons such as carbon tetrachloride, trichlorethylene, and tetrabromoethane; ethyl ether; , dimethyl glycol, trioxane, tetrahydrofuran, and other ethers; methylal, diethyl acetal, and other acetals;
Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane; Esters such as butyl formate, butyl acetate, ethyl propionate, and cellosolve acetate; Acids such as formic acid, acetic acid, and propionic acid; Nitropropene, nitrobenzene, and dimethylamine , sulfur- and nitrogen-containing organic compounds such as monoethanolamine, pyridine, dimethyl sulfoxide, and dimethyl formamide;
Also includes water.

[0022] In the above-mentioned solvent mainly composed of a hydrophilic organic liquid, SO4 ions (-2 valence), NO2 ions (-1 valence), P
O4 ion (-3 valence), Cl ion (-1 valence), Na ion (+1 valence), K ion (+1 valence), Mg ion (+
Polymerization may be carried out in the presence of Ca ions (+2 valence), Ca ions (+2 valence), and other inorganic ions. Furthermore, by changing the type and composition of the mixed solvent at the start of polymerization, during polymerization, and at the end of polymerization, it is possible to adjust the average particle size, particle size distribution, drying conditions, etc. of the resulting polymer particles.

[0023] Suitable examples of the polymeric dispersants used during the production of the seed particles or the production of the grown particles include:
For example, acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride; acrylic monomers containing hydroxyl groups, such as acrylic β-hydroxyethyl acid, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxy acrylate Propyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide, etc.; vinyl Ethers of alcohol or vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc.; Esters of vinyl alcohol and compounds containing a carboxyl group, such as vinyl acetate, vinyl propionate, vinyl butyrate, etc.; acrylamide, Methacrylamide, diacetone acrylamide or their methylol compounds; acid chlorides such as acrylic acid chloride and methacrylic acid chloride; homogeneous substances having nitrogen atoms or their heterocycles such as vinylpyridine, vinylpyrrolidone, vinylimidazole, and ethyleneimine; Polymer or copolymer system; polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl Examples include polyoxyethylene-based ethers, polyoxyethylene stearyl phenyl ether, polyoxyethylene nonylphenyl ether, and celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

[0024] Furthermore, the above hydrophilic monomer and styrene, α
- Those having a benzene nucleus such as methylstyrene and vinyltoluene, derivatives thereof, or copolymers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; Furthermore, crosslinking monomers such as ethylene glycol dimethacrylate, Copolymers with diethylene glycol dimethacrylate, allyl methacrylate, divinylbenzene, etc. can also be used.

These polymeric dispersants are appropriately selected depending on the hydrophilic organic liquid used, the desired species of polymer particles, and the production of seed particles or grown particles. In order to mainly sterically prevent this, a material is selected that has high affinity and adsorption to the polymer particle surface, and high affinity and solubility to hydrophilic organic liquids. In addition, in order to enhance the repulsion between particles sterically, those with molecular chains of a certain length, preferably those with a molecular weight of 10,000 or more, are selected. However, if the molecular weight is too high, the viscosity of the liquid will increase significantly, resulting in poor operability and stirring performance, and the probability of precipitation of the produced polymer on the particle surface will vary, so care must be taken. In addition, some of the monomers of the polymer dispersant mentioned above,
It is also effective for stabilization to coexist with the monomers constituting the target polymer particles.

Furthermore, in addition to these polymeric dispersants, metals such as cobalt, iron, nickel, aluminum, copper, tin, lead, magnesium, etc. or their alloys (particularly preferably those with a particle size of 1 μm or less); iron oxide, copper oxide , inorganic compound fine powder of oxides such as nickel oxide, zinc oxide, titanium oxide, and silicon oxide; anionic surfactants such as higher alcohol sulfate ester salts, alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters; alkylamine salt,
Amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, and quaternary ammonium salts such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridium salts, alkylisoquinolinium salts, and benzethonium chloride. Salt type cationic surfactants; nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; for example, alanine type [e.g. dodecyl di(
aminoethyl)glycine, di(octylaminoethyl)
Even when an amino acid type or betaine type amphoteric surfactant such as [glycine] is used in combination, the stability and particle size distribution of the produced polymer particles can be further improved.

In general, the amount of polymer dispersant used during the production of seed particles varies depending on the type of polymerizable monomer for forming the desired polymer particles, but it is usually 0.
．． It is 1 to 10% by weight, preferably 1 to 5% by weight. When the concentration of the polymer dispersant is low, the resulting polymer particles have a relatively large particle size, and when the concentration is high, the polymer particles have a small particle size. Even if it is used in excess, there is little effect on reducing the particle size.

[0028] The above-mentioned polymeric dispersants and inorganic fine powders, pigments, and surfactants added as necessary are not only necessary during the production of seed particles, but also during the growth reaction. In order to prevent particles from coalescing, they may be present in the vinyl monomer solution or seed particle dispersion to be added for polymerization.

The initially formed particles are stabilized by a polymeric dispersant distributed in a balanced manner in the hydrophilic organic liquid and on the surface of the polymer particles, but the unreacted vinyl monomer is stabilized by the hydrophilic organic liquid. If it is present in a large amount in the liquid, it will have a somewhat swollen viscosity and will overcome the steric repulsion of the polymeric dispersant and coagulate. Furthermore, if the amount of monomer is extremely large relative to the hydrophilic organic liquid, the resulting polymer will be completely dissolved and will not precipitate until the polymerization has progressed to a certain extent. In this case, the state of precipitation is such that highly sticky lumps are formed. Therefore, the amount of monomer to hydrophilic organic liquid when producing particles is naturally limited, and although it varies somewhat depending on the type of hydrophilic organic liquid, the monomer/hydrophilic organic liquid ratio is approximately 1 or less,
Preferably, 1/2 or less is appropriate.

[0030] Furthermore, the above-mentioned vinyl monomer is one that can be dissolved in a hydrophilic organic liquid, such as styrene, o-
Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,
4-dimethylstyrene, p-n-butylstyrene, p-
tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-
Styrenes such as chlorostyrene and 3,4-dichlorostyrene; 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, phenyl acrylate, methyl α-chloroacrylate,
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, α-methyl fatty acid monocarboxylic acid esters such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; vinyl chloride, vinylidene chloride, vinyl bromide, fluoride It means a mixture of halogenated vinyl such as vinyl alone or a mixture thereof, and a monomer containing 50% by weight or more of these and copolymerizable with them.

Further, the polymer used in the present invention may be polymerized in the presence of a so-called crosslinking agent having two or more polymerizable double bonds in order to improve offset resistance. Preferably used crosslinking agents include divinylbenzene, divinylnaphthalene, and aromatic divinyl compounds that are derivatives thereof, as well as ethylene glycol dimethacrylate, diethylene glycol methacrylate,
triethylene glycol methacrylate, trimethylolpropane triacrylate, allyl methacrylate,
Diethylene carboxylic acid esters such as tert-butylaminoethyl methacrylate, tetraethylene glycol methacrylate, and 1,3-butanediol dimethacrylate; all divinyl compounds such as N,N-divinylaniline, divinyl ether, divinyl sulfide, and divinyl sulfone; Compounds having two or more vinyl groups can be mentioned, and these can be used alone or as a mixture.

[0032] When a growth polymerization reaction is successively carried out using the seed particles crosslinked in this manner, the interior of the growing polymer particles becomes crosslinked. On the other hand, when the vinyl monomer solution used in the growth reaction contains the above-mentioned crosslinking agent, a polymer having a hardened particle surface can be obtained.

In the production of resin particles, polymerization may be carried out in the presence of a compound having a large chain transfer constant for the purpose of controlling the average molecular weight. for example,
Examples include low molecular weight compounds having a mercapto group, carbon tetrachloride, carbon tetrabromide, and the like.

[0034] Furthermore, as the polymerization initiator for the monomer,
For example, 2,2'-azobisisobutyronitrile, 2,2
Azo polymerization initiators such as '-azobis(2,4-dimethylvaleronitrile), peroxide polymerization initiators such as lauryl peroxide, benzoyl peroxide, tert-butyl peroctoate, potassium persulfate, etc. A persulfide-based initiator or a system in which it is combined with sodium thiosulfate, an amine, etc. is used. The concentration of the polymerization initiator is 0.1 to 1 with respect to 100 parts by weight of vinyl monomer.
0 parts by weight is preferred.

The polymerization conditions for obtaining resin particles A include the concentration and blending of the polymer dispersant and vinyl monomer in the hydrophilic organic liquid in accordance with the target average particle size and target particle size distribution of the polymer particles. The ratio is determined. Generally, if the average particle size of the particles is to be made small, the concentration of the polymeric dispersant is set high, and if the average particle size is to be made large, the concentration of the polymeric dispersant is set to be low. On the other hand, if you want to make the particle size distribution very sharp, you need to lower the vinyl monomer concentration and
If a relatively wide distribution is acceptable, the vinyl monomer concentration is set high.

The resin particles A are manufactured by completely dissolving the polymer dispersant in a hydrophilic organic liquid, and then adding one or more vinyl monomers, a polymerization initiator, and other inorganic fine powders as necessary. Adding surfactants, dyes, pigments, etc., 30 to 300
With normal stirring at rpm, preferably at the lowest possible speed,
Moreover, by using turbine-type stirring blades rather than paddle-type stirring blades at a speed that makes the flow uniform in the tank, and heating at a temperature corresponding to the decomposition rate of the initiator used, polymerization is carried out. It is done. Note that since the temperature at the initial stage of polymerization has a large effect on the particle size produced, it is desirable to raise the temperature to the polymerization temperature after adding the monomers and to dissolve the initiator in a small amount of solvent before adding it. During polymerization, it is necessary to sufficiently expel oxygen in the air in the reaction vessel using an inert gas such as nitrogen gas or argon gas. If the oxygen purge is insufficient, fine particles are likely to be generated.

In order to carry out polymerization in a high polymerization rate range, 5 to 40
Although several hours of polymerization time is required, the polymerization rate can be accelerated by stopping the polymerization when the desired particle size and particle size distribution are achieved, by sequentially adding a polymerization initiator, or by conducting the reaction under high pressure. be able to. After polymerization, the polymer slurry can be used as it is for the dyeing process, or it can be used as a polymer slurry after removing unnecessary fine particles, residual monomers, polymer dispersants, etc. through operations such as sedimentation, centrifugation, and decantation. It may be collected as a dye and dyed. However, if the polymer dispersant is not removed, the dyeing system will be more stable and unnecessary aggregation will be suppressed.

In the present invention, small resin particles with a narrow particle size distribution, preferably resin particles A obtained as described above, are first dyed by a conventional method. As a dyeing method,
Although any method may be employed, the following method is particularly preferred. That is, the resin particles are dispersed in an organic solvent that does not dissolve the resin particles, and before and after dissolving the dye in the solvent, the dye is infiltrated into the resin particles to color them, and then,
In the method for obtaining a dyed toner by removing the solvent, the solubility of the dye in the organic solvent [D
1] and the solubility [D2] of the dye in the resin of the resin particles has a relationship of [D1]/[D2]≦0.5 (particularly preferably [D1]/[D2]≦0.2). According to this method, it is possible to efficiently produce a toner in which the dye penetrates (diffuses) deep into the resin particles.

In addition, in the above dyeing method, the solubility is 2
Defined as measured at a temperature of 5°C. The solubility of the dye in the resin has exactly the same definition as the solubility of the dye in the solvent, and means the maximum amount of the dye that can be contained in the resin in a compatible state. The state of dissolution or the state of precipitation of the dye can be easily observed using a microscope. Note that in order to know the solubility of the dye in the resin, an indirect observation method may be used instead of the above-mentioned direct observation method. This method is
A liquid having a solubility coefficient similar to that of the resin, that is, a solvent that dissolves the resin well, is used, and the solubility of the dye in this solvent is determined as the solubility in the resin.

In addition, as dyes, water-soluble dyes such as cationic dyes and anionic dyes may be subject to large environmental fluctuations, and the resistance of the toner may become low, resulting in deterioration of the transfer rate, so vat dyes, Disperse dyes and oil-soluble dyes are preferably used, and oil-soluble dyes are particularly preferred. Note that several types of dyes can be used in combination depending on the desired color tone. The ratio (weight) of the dye to be dyed and the resin particles is arbitrarily selected depending on the degree of coloring, but it is usually preferably 1 to 50 parts by weight of the dye to 100 parts by weight of the resin particles.

For example, when alcohols such as methanol or ethanol with a high SP value are used as the dyeing solvent and styrene/acrylic resin with an SP value of about 9 is used as the resin particles, the dyes that can be used include, for example. The following dyes can be mentioned. C. I. SOLVENT YELLOW(6,9,1
7, 31, 35, 100, 102, 103, 105)C
．． I. SOLVENT Orange (2, 7, 13
, 14, 66) C. I. SOLVENT RED (5
,16,17,18,19,22,23,143,14
5,146,149,150,151,157,158
) C. I. SOLVENT VIOLET(31,3
2,33,37)C. I. SOLVENT BLUE
(22, 63, 78, 83-86, 91, 94, 95,
104)C. I. SOLDENT GREEN (24
, 25) C. I. SOLDENT Brown (3,
9) etc.

Commercially available dyes include, for example, vertical dye SOT dye Yellow-1, 3, 4, Orange, manufactured by Hodogaya Chemical Industry Co., Ltd.
e-1, 2, 3, Scarlet-1, Red-1, 2
,3,Brown-2,Blue-1,2,Viole
t-1, Green-1, 2, 3, Black-1, 4
, 6, 8 and BASF's sudan dye, Yellow
-140,150, Orange-220, Red-2
90, 380, 460, Blue-670, Mitsubishi Kasei Diaresin, Yellow-3G, F, H2G, H
G, HC, HL, Orange-HS, G, Red-G
G, S, HS, A, K, H5B, Violet-D, B
lue-J, G, N, K, P, H3G, 4G, Green
n-C, Brown-A, orient chemical oil color, Yellow-3G, GG-S, #105, Or
ange-PS, PR, #201, Scarlet-#
308, Red-5B, Brown-GR, #416,
Green-BG, #502, Blue-BOS, II
N, Black-HBB, #803, EE, EX, Sumitomo Chemical Co., Ltd. Sumiplast, Blue GP, OR, Red FB, 3B, Yellow FL7G, GC, Nippon Kayaku Co., Ltd. Kayalon, Polyester Black EX-SH300, Kayaset Red -B Blue A-2R, etc. can be used. Of course, the dye is not limited to the above example, since it is appropriately selected depending on the combination of the resin particles and the solvent used during dyeing.

[0043] The organic solvent used for dyeing the resin particles with the dye is one that does not dissolve the resin particles used, or one that causes some swelling, specifically, the solubility parameter [SP value] of the organic solvent. The difference between the [SP value] and the resin particles used is 1.0 or more, preferably 2.0 or more. For example, for styrene/acrylic resin, alcohols such as methanol, ethanol, n-propanol, etc., which have a high [SP value], or n-hexane, n-heptane, etc., which have a low [SP value], are used. Of course, if the difference in [SP value] is too large, wetting to the resin particles will be poor and good dispersion of the resin particles will not be obtained, so the difference in [SP value] is preferably 2 to 5.

[0044] When dyeing is carried out, it is preferable to disperse the resin particles in an organic solvent in which the dye is dissolved, and then maintain the liquid temperature at a temperature below the glass transition temperature of the resin particles and stir the mixture. This prevents agglomeration of resin particles and makes it possible to dye them. Stirring may be carried out using a commercially available stirrer, such as a homomixer or a magnetic stirrer.

Alternatively, the dye may be directly added to the slurry obtained at the end of dispersion polymerization, that is, a solution in which polymerized resin particles are dispersed in an organic solvent, and then heated and stirred under the above conditions. good. If the heating temperature exceeds the glass transition temperature, resin particles will fuse together.

The method of drying the slurry after dyeing is not particularly limited, but it may be air-dried after filtration, vacuum drying after filtration, or direct vacuum drying without filtration. In the present invention, the colored particles obtained by air drying or vacuum drying after filtration have almost no agglomeration, and reproduce the particle size distribution of the introduced resin particles with almost no damage.

In the present invention, as mentioned above, the surface friction coefficient of the toner is 0.8 or less, and as a result,
Problems such as poor transfer and poor mixing with carrier are solved. The simplest method for reducing the surface friction coefficient of toner to 0.8 or less is to mechanically inject charge control agent particles onto the surface of dried resin particles after dyeing. In addition,
Supplementary heating may be used during driving. In this case, by setting the size of the charge control agent particles to 1 μm or less, the charge control agent particles are firmly implanted into the surface of the resin particles, particularly to the extent that they do not easily separate in the developer.

[0048] The ratio of the charge control agent to the colored resin particles is such that the surface friction coefficient is 0.8 or less.
Wide selection. Generally, 0.5 to 10 parts by weight of the charge control agent is preferably used per 100 parts by weight of the colored resin particles.

As for the method of implanting the charge control agent, the colored resin particles and the charge control agent are mixed in advance, and then mechanical energy is applied. Mixing method: ball mill, V
Any blender, Henschel, etc. will do. Methods of applying mechanical energy include applying impact force to the mixture using blades rotating at high speed, accelerating the particles by introducing the mixture into high-speed airflow, and causing the particles to collide with each other or against a suitable collision plate. There is. Specific equipment includes an Ong Mill (Hosokawa Micron Corporation), an I-type mill (Japan Pneumatic Industries) with lower air pressure for grinding than normal grinding, a hybridization system (Nara Kikai Seisakusho), Examples include automatic mortar.

Specific examples of the charge control agent include the following. nigrosine, azine dye containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 1627/1983),
Basic dyes [for example, C.I. I. Basic Yellow
w 2 (C.I.41000), C.I. I. Basic
Yellow 3, C. I. Basic Red 1 (
C. I. 45160), C. I. Basic Red
9 (C.I.42500), C.I. I. Basic Vi
olet1 (C.I.42535), C. I. Basi
c Violet 3 (C.I.42555), C.I. I
．． BasicViolet 10 (C.I.45170
), C. I. BasicViolet 14 (C.I.
．． 42510), C. I. Basic Blue 1 (
C. I. 42025), C. I. Basic Blue
e 3 (C.I.51005), C. I. Basic
Blue 5 (C.I.42140), C.I. I. Bas
ic Blue 7 (C.I.42595), C.I. I.
Basic Blue 9 (C.I.52015), C
．． I. Basic Blue24 (C.I.52030
), C. I. Basic Blue25 (C.I.52
025), C. I. Basic Blue 26 (C.
I. 44045), C. I. Basic Green
1 (C.I.42040), C.I. I. Basic Group
een4 (C.I.42000)], lake pigments of these basic dyes, (lake forming agents include phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferric acid, C.I. I. Sovent
Black 3 (C.I.26150), Hansa Yellow G (C.I.11680), C.I. I. Mordl
ant Black 11,C. I. Pigment
Black1, benzolmethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, or dialkyltin compounds such as dibutyl or dioctyl, dialkyltin borate compounds, guanidine derivatives, vinyl polymers containing amino groups,
Polyamine resins such as condensation polymers containing amino groups, Japanese Patent Publication Nos. 41-20153 and 43-27596,
Metal complex salts of monoazo dyes described in No. 44-6397 and No. 45-26478. Tokuko Sho 55-4275
No. 2, Special Publication No. 58-41508, Special Publication No. 58-738
Metal complexes of salicylic acid, dialkyl salicylic acid, naphthoic acid, dicarboxylic acid such as Zn, Al, Co, Cr, Fe, etc., and sulfonated copper phthalocyanine pigments, etc., described in Japanese Patent Publication No. 59-7385.

[0051] In the toner of the present invention, recrystallization,
Microparticles with a relatively high Tg that have been atomized by means such as crushing or emulsification, such as PMMA (polymethyl methacrylate), PTFE (polytetrafluoroethylene), P
It is also possible to implant submicron particles such as VDF (polyvinylidene fluoride). Further, in the toner of the present invention, a release agent such as polyolefin, fatty acid ester, fatty acid metal salt, higher alcohol, paraffin wax, etc. can be applied to the surface of the toner. When performing implantation treatment, it may be performed simultaneously with implantation of the charge control agent, or it may be performed separately before and after implantation.

Furthermore, in the toner of the present invention, additives can be contained in the toner particles. As the additive in this case, known fine particles such as titanium oxide particles, hydrophobic silica particles, zinc stearate, and magnesium stearate are used. The mixing method is a V blender,
A common mixing device such as a ball mill may be used.

[0053]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. Note that all parts and percentages shown below are based on weight.

Example 1 First, base particles were produced by the dispersion polymerization method as described below. That is, 320 parts of methanol was placed in a three-necked flask equipped with a stirring blade and a condenser, and 6.4 parts of polyvinylpyrrolidone (average molecular weight: 40,000) was added little by little with stirring to completely dissolve it. Furthermore, the following composition was added and completely dissolved. styrene
25.6 copies
n-butyl methacrylate
6.4 parts 2,2'-azobisisobutyronitrile 0.2 parts

[
While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was started in a constant temperature water bath at 60° C.±0.1° C. while stirring at a stirring speed of 200 rpm. 15 minutes after heating, the liquid begins to become cloudy and 2
Even after 0 hours of polymerization, the dispersion remained cloudy and stable. A portion of the sample was measured using gas chromatography using an internal standard method, and as a result, the polymerization rate was confirmed to be 92%.

When the obtained dispersion was cooled and centrifuged at 2000 rpm using a centrifuge, the polymer particles were completely settled and the upper liquid was transparent. The supernatant liquid was removed, 200 parts of methanol was newly added, and the mixture was stirred and washed for 1 hour. The procedure of centrifuging and washing with methanol was repeated, followed by filtration. The filtered product was dried under reduced pressure at 50° C. for 24 hours to obtain white powder styrene/n-butyl methacrylate copolymer particles with a yield of 95%. The obtained particles had a volume average particle diameter Dv=6.40 μm and a Dv/Dp=1.07 (number average particle diameter 5.98 μm). Also, Tg is 65
It was ℃.

Next, 1.0 part of Oil Black 803 (Orient Chemical Co., Ltd.) was heated and dissolved in 200 parts of methanol, cooled, and filtered through a 1 μm filter to prepare a dye solution. Subsequently, 24 parts of the above-mentioned copolymer particles were added to the filtrate to disperse it, and the mixture was heated and stirred at 50° C. for 1 hour. Thereafter, the dispersion was cooled to room temperature and filtered, and then heated to 50°C for 24 hours.
It was dried under reduced pressure for hours to obtain colored resin particles.

100 parts of the colored resin particles and charge control agent 3
, 3 parts of 5-di-tert-butylsalicylic acid zinc salt in an Ooster blender for 5 minutes, and then treated with a hybridization system NHS-1 (manufactured by Nara Kikai Seisakusho) at a rotation speed of 7000 rpm for 5 minutes. Obtained inventive toner.

The charge amount of the obtained toner was measured using a blow-off device and was found to be -24.0 (μC/g). Moreover, the surface friction coefficient was 0.76. Using this toner, the Ricoh digital copier Imagio 420
When an image was formed using this method, a clear image with good fine line reproducibility, vivid halftones, and no cleaning defects was obtained.

Example 2 First, base particles were produced by the dispersion polymerization method as described below. That is, 320 parts of methanol was placed in a three-necked flask equipped with a stirring blade and a condenser, and 6.4 parts of polyvinylpyrrolidone (average molecular weight: 40,000) was added little by little with stirring to completely dissolve it. Furthermore, the following composition was added and completely dissolved. styrene
25.6 copies
n-butyl methacrylate
6.0 parts 2,2'-azobisisobutyronitrile 0.16 parts

While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was started in a constant temperature water bath at 62° C.±0.1° C. while stirring at a stirring speed of 200 rpm. 15 minutes after heating, the liquid begins to become cloudy.
Even after 20 hours of polymerization, the dispersion remained cloudy and stable. As a result of measuring a portion of the sample using gas chromatography using an internal standard method, it was confirmed that the polymerization rate was 93%.

When the obtained dispersion was cooled and centrifuged at 2000 rpm using a centrifuge, the polymer particles were completely sedimented and the upper liquid was transparent. The supernatant liquid was removed, 200 parts of methanol was newly added, and the mixture was stirred and washed for 1 hour. The procedure of centrifuging and washing with methanol was repeated, followed by filtration. The filtered product was dried under reduced pressure at 50° C. for 24 hours to obtain white powder styrene/n-butyl methacrylate copolymer particles with a yield of 96%. The obtained particles had a volume average particle size Dv=6.58 μm and a Dv/Dp=1.04 (number average particle size 6.34 μm). Also, Tg is 65
It was ℃.

Next, 1.0 part of Oil Black 803 (Orient Chemical Co., Ltd.) was heated and dissolved in 200 parts of methanol, cooled, and filtered through a 1 μm filter to prepare a dye solution. Subsequently, 24 parts of the above-mentioned copolymer particles were added to the filtrate to disperse it, and the mixture was heated and stirred at 50° C. for 1 hour. Thereafter, the dispersion was cooled to room temperature and filtered, and then heated to 50°C for 24 hours.
It was dried under reduced pressure for hours to obtain colored resin particles.

100 parts of the colored resin particles and charge control agent 3
, 5 parts of 5-di-tert-butylsalicylic acid zinc salt in an Ooster blender for 5 minutes, and then mixed in a hybridization system NHS-1 at 7000 rpm.
rpm for 5 minutes to obtain the toner of the present invention.

The amount of charge of the obtained toner was measured using a blow-off device and was found to be -23.4 (μC/g). Moreover, the surface friction coefficient was 0.78. When an image was formed using Imageo 420 using this toner, a clear image with good fine line reproducibility, vivid halftones, and no cleaning defects was obtained.

Example 3 First, base particles were produced by the dispersion polymerization method as described below. That is, 320 parts of methanol was placed in a three-necked flask equipped with a stirring blade and a condenser, and 6.4 parts of polyvinylpyrrolidone (average molecular weight: 40,000) was added little by little with stirring to completely dissolve it. Furthermore, the following composition was added and completely dissolved. styrene
25.6 copies
n-butyl methacrylate
6.4 parts 2,2'-azobisisobutyronitrile 0.2 parts

[
While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was started in a constant temperature water bath at 60° C.±0.1° C. while stirring at a stirring speed of 200 rpm. 15 minutes after heating, the liquid begins to become cloudy and 2
Even after 0 hours of polymerization, the dispersion remained cloudy and stable. A portion of the sample was measured using gas chromatography using an internal standard method, and as a result, the polymerization rate was confirmed to be 92%.

When the obtained dispersion was cooled and centrifuged at 2000 rpm using a centrifuge, the polymer particles were completely sedimented and the upper liquid was transparent. The supernatant liquid was removed, 200 parts of methanol was newly added, and the mixture was stirred and washed for 1 hour. The procedure of centrifuging and washing with methanol was repeated, followed by filtration. The filtered product was dried under reduced pressure at 50° C. for 24 hours to obtain white powder styrene/n-butyl methacrylate copolymer particles with a yield of 95%. The obtained particles had a volume average particle diameter Dv=7.40 μm and a Dv/Dp=1.07 (number average particle diameter 6.92 μm). Also, Tg is 65
It was ℃.

Next, 1.0 part of Oil Black 803 (Orient Chemical Co., Ltd.) was heated and dissolved in 200 parts of methanol, cooled, and filtered through a 1 μm filter to prepare a dye solution. Subsequently, 24 parts of the above-mentioned copolymer particles were added to the filtrate to disperse it, and the mixture was heated and stirred at 50° C. for 1 hour. Thereafter, the dispersion was cooled to room temperature and filtered, and then heated to 50°C for 24 hours.
It was dried under reduced pressure for hours to obtain colored resin particles.

100 parts of the colored resin particles and charge control agent 3
, 2 parts of 5-di-tert-butylsalicylic acid zinc salt in an Ooster blender for 5 minutes, and then mixed in a hybridization system NHS-1 at 7000 rpm.
rpm for 5 minutes to obtain the toner of the present invention.

The amount of charge of the obtained toner was measured using a blow-off device and found to be -19.6 (μC/g). When an image was formed using Imageo 420 using this toner, a clear image with good fine line reproducibility, vivid halftones, and no cleaning defects was obtained. Of the adhesive force components that act between the toners of the obtained toner, the adhesive force when the load applied to the toner is zero is 6.5.
gf/cm2, and the adhesion force in the packed state is 24.1 gf when a load of 70 gf/cm2 is applied.
/cm2, and the surface friction coefficient of the toner is 0.67.
Met.

Example 4 First, base particles were produced by the dispersion polymerization method as described below. That is, 320 parts of methanol was placed in a three-necked flask equipped with a stirring blade and a condenser, and 6.4 parts of polyvinylpyrrolidone (average molecular weight: 40,000) was added little by little with stirring to completely dissolve it. Furthermore, the following composition was added and completely dissolved. styrene
27.0 copies
n-butyl methacrylate
5.0 parts 2,2'-azobisisobutyronitrile 0.2 parts

[
While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Polymerization was started in a constant temperature water bath at 60° C.±0.1° C. while stirring at a stirring speed of 200 rpm. 15 minutes after heating, the liquid begins to become cloudy and 2
Even after 0 hours of polymerization, the dispersion remained cloudy and stable. A portion of the sample was measured using gas chromatography using an internal standard method, and as a result, it was confirmed that the polymerization rate was 95%.

When the obtained dispersion was cooled and centrifuged at 2000 rpm using a centrifuge, the polymer particles were completely sedimented and the upper liquid was transparent. The supernatant liquid was removed, 200 parts of methanol was newly added, and the mixture was stirred and washed for 1 hour. The procedure of centrifuging and washing with methanol was repeated, followed by filtration. The filtered product was dried under reduced pressure at 50° C. for 24 hours to obtain white powder styrene/n-butyl methacrylate copolymer particles with a yield of 96%. The obtained particles had a volume average particle size Dv=7.24 μm and a Dv/Dp=1.11 (number average particle size 6.55 μm). Also, Tg is 65
It was ℃.

Next, 1.0 part of Oil Black 803 (Orient Chemical Co., Ltd.) was heated and dissolved in 200 parts of methanol, cooled, and filtered through a 1 μm filter to prepare a dye solution. Subsequently, 24 parts of the above-mentioned copolymer particles were added to the filtrate to disperse it, and the mixture was heated and stirred at 50° C. for 1 hour. Thereafter, the dispersion was cooled to room temperature and filtered, and then heated to 50°C for 24 hours.
It was dried under reduced pressure for hours to obtain colored resin particles.

100 parts of the colored resin particles and charge control agent 3
, 2 parts of 5-di-tert-butylsalicylic acid zinc salt in an Ooster blender for 5 minutes, and then mixed in a hybridization system NHS-1 at 7000 rpm.
rpm for 5 minutes to obtain the toner of the present invention.

The amount of charge of the obtained toner was measured using a blow-off device and was found to be -20.6 (μC/g). When an image was formed using Imageo 420 using this toner, a clear image with good fine line reproducibility, vivid halftones, and no cleaning defects was obtained. Furthermore, among the adhesive force components that act between the toners of the obtained toner, the adhesive force when the load applied to the toner is zero is 4.2.
gf/cm2, and the adhesion force in the packed state is 18.4 gf when a load of 70 gf/cm2 is applied.
/cm2, and the surface friction coefficient of the toner is 0.76.
Met.

Comparative Example A toner was prepared in the same manner as in Example 1, except that the charge control agent was not implanted.

The charge amount of the obtained toner was measured using a blow-off device and was found to be +16.5 μC/g. Moreover, the surface friction coefficient was 1.24. When an image was formed using Imageo 420 using this toner, an image with background stains was obtained on the entire surface.

[0080]

Effects of the Invention The electrostatic image developing toner according to claim 1 has a ratio of volume average particle diameter (Dv) to number average particle diameter (Dp) [Dv
/Dp]=1.00 to 1.20 and (Dv)=5 to 1
Since the toner has a structure in which resin particles having a diameter of 0 μm are used as the matrix and the surface friction coefficient of the toner is 0.8 or less, the following outstanding effects can be achieved. (b) It is possible to obtain high-quality images with excellent resolution, sharpness, halftone reproducibility, and photographic reproducibility. (b) There is little change in the amount of charge due to the environment, and the particle size distribution and charge amount of the toner in the developer do not change even after long periods of use.
It is highly reliable. (c) Cleanability is very good.

Furthermore, the toner for developing an electrostatic image of claim 2 has an adhesion force of 10 gf/cm2 or less when no load is applied to the toner among the adhesion components acting between the toners,
In addition, since a requirement has been added that the adhesion force in the packed state when a load of 70 gf/cm2 is applied is 30 gf/cm2 or less, the effect of further improving cleaning performance is added.

Claims (2)

[Claims] Claim 1: The ratio of volume average particle diameter (Dv) to number average particle diameter (Dp) [Dv/Dp] is 1.00 to 1.20, and the volume average particle diameter (Dv) is 1 to 10 μm. 1. A toner for developing an electrostatic image, which is a toner having resin particles as a base material and having a surface friction coefficient of 0.8 or less. 2. Among the adhesive force components acting between the toners,
The adhesion force when the load applied to the toner is zero is 10 gf.
/cm2 or less, and the adhesion force in the packed state when a load of 70gf/cm2 is applied is 30gf/c
2. The toner for developing an electrostatic image according to claim 1, wherein the toner has a particle size of m2 or less.