JP2001175024A - Electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner adaptable to the enhancement of resolution and gradation. SOLUTION: The electrostatic charge image developing toner comprises a resin composition for a toner containing at least a bonding resin and a colorant and has 4-9 μm volume average particle diameter. The proportion of the number of particles whose particle diameter is <=40% of the volume average particle diameter to the number of all particles is <=9.0%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge developing toner for developing an electrostatic latent image in an electrophotographic image forming method.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic image forming method, a photoreceptor made of a photoconductive substance is uniformly charged, and then exposed, and then the charge in the exposed portion is dissipated to statically charge. A latent electrostatic image is formed, and the latent electrostatic image is visualized and developed by attaching charged toner to unexposed portions, and the resulting visible image is transferred to a transfer material such as transfer paper. A method of fixing the visible image to a transfer material by heating, pressing, or the like is often used.

[0003] With the spread of computers and the improvement of their capabilities in recent years, not only character images and the like but also photographic images are handled, and accordingly, copiers and printers are required to have higher resolution and higher gradation. However, there is a limit in the measures in terms of the device, and there is an expectation for measures in terms of the toner as a developer.

On the other hand, as a conventional method for producing a toner,
A pulverization method is mainly employed by pulverizing and classifying a resin composition obtained by melt-kneading a binder resin and a colorant, or further a releasing agent, a charge controlling agent, and the like. Since the shape of the particles is irregular, it is not always suitable for high resolution and high gradation, and there is a limit to reducing the particle size, and furthermore, because a classification process is required, it is economical. There was also a disadvantage.

On the other hand, a suspension polymerization method in which a binder resin component monomer is subjected to suspension polymerization in the presence of a colorant or the like, or an emulsion obtained by emulsion polymerization of a binder resin component monomer is used as a colorant. In the former suspension polymerization method, the shape of the resin particles after polymerization is a true sphere, and the toner particles are formed in a toner. Although the particle size becomes suitable for high image quality, it is difficult to control the particle size distribution, and it cannot respond to high resolution and high gradation.
In the latter emulsion polymerization agglomeration method, although it is possible to respond tentatively to high resolution and high gradation, the particle size distribution due to polymerization conditions and aggregation conditions is not always stable, and often high resolution and high There is a problem that a case where it is impossible to cope with high gradation occurs.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and accordingly, the present invention provides a toner for electrostatic charge development capable of coping with high resolution and high gradation. The purpose is to:

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and have found that the average particle size of the toner is in a specific range and the number of fine particles is in a specific range. The present invention has been found that the above object can be achieved, that is, the present invention comprises a resin composition for toner containing at least a binder resin and a colorant, and has a volume average particle diameter of 4 to 9 μm. A toner for developing an electrostatic image, wherein the ratio of the number of particles having a particle size of 40% or less of the volume average particle size to the total number of particles is 9.0% or less;
Is the gist.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the binder resin constituting the resin composition for a toner is not particularly limited, and a styrene resin, a polyester resin, a polyamide resin, a polycarbonate resin, and a Vinyl chloride resin, polyolefin resin, polyphenylene ether resin, polyvinyl butyral resin, ketone resin, acrylic resin, fluorine resin, urethane resin,
Various resins generally used as a binder resin, such as an epoxy resin, can be used. Among them, in the present invention, a styrene resin represented by a styrene- (meth) acrylate copolymer and a polyester resin are preferable.

The binder resin has a glass transition temperature of 40 to 40.
The temperature is preferably 80 ° C, more preferably 55 to 70 ° C, particularly preferably 58 to 65 ° C.
If the glass transition temperature is lower than the above range, the storage stability as a toner tends to decrease, while if the glass transition temperature is higher than the above range, fixing of an image to a transfer material becomes poor or an image having good transparency is obtained. Tends to be difficult.

In the present invention, the colorant constituting the resin composition for a toner is not particularly limited, and various organic and inorganic pigments and dyes generally used as a colorant for a toner may be used. Can be used.

For example, the colorant used for the black toner includes, for example, carbon black, magnetite, and aniline black. Carbon black is preferable for non-magnetic toner, and magnetite is preferable for magnetic toner.

The carbon black is preferably produced by the furnace method. The carbon black has a specific surface area of 20 to 500 m ² / g by nitrogen adsorption by the BET method and a dibutyl phthalate (DBP) oil absorption of 30 to 150 ml / g. 10
0 g is preferred. For non-magnetic one-component negatively charged toners, acidic carbon black having a carbon black suspension having a pH of 6 or less after boiling in pure water is preferred.

For yellow toner, for example,
C. I. Pigment Yellow 1, 3, 74, 9
Acetoacetic acid arylamide monoazo yellow pigments such as C.7 and 98; I. Pigment Yellow 12, 13
Azoacetoacetate arylamide-based disazo yellow pigments such as C.I. I. Pigment Yellow 93, 1
55, a condensed monoazo yellow pigment such as C.55. I. Isoindoline pigments such as C.I. Pigment Yellow 109, 110, 137 and 173; I. Other yellow pigments such as CI Pigment Yellow 150, 180 and 185; I. Solvent Yellow 19, 77, 79
C. I. And yellow dyes such as Disperse Yellow 164. I. Pigment Yellow 1
3, 17, 74, 93, 150, 155, 180 and 185 yellow pigments are preferred.

Further, for magenta toner, for example,
C. I. Pigment Red 48, 49: 1, 5
3: 1, 57, 57: 1, 81, 122, 5, 146, 184, 238, C.I. I. Red or red pigments such as CI Pigment Violet 19; I. Red dyes such as Solvent Red 49, 52, 58, and 8; I. Pigment Red 57: 1, 122, 146, 184,
238, C.I. I. Red or red pigments such as CI Pigment Violet 19 are preferred.

For cyan toner, for example,
C. I. Pigment Blue 15: 3, 15: 4 and the like, and a copper phthalocyanine or a derivative-based blue pigment;
I. And green pigments such as CI Pigment Green 7 and 36 (phthalocyanine green). I.
Pigment Blue 15: 3 and Blue Pigment 15: 4 are preferred.

The content of the colorant in the resin composition for toner is 1 to 100 parts by weight of the binder resin.
It is preferably 15 parts by weight, more preferably 2 to 10 parts by weight.

The resin composition for a toner according to the present invention contains at least the binder resin and the colorant, and preferably further contains a wax as a release agent. For example, low-molecular-weight polyethylene, low-molecular-weight polypropylene, polyolefin-based wax such as ethylene-propylene copolymer, paraffin-based wax, stearic acid ester, behenic acid ester, ester wax having a long-chain aliphatic group such as montanic acid ester, Hydrogenated castor oil, vegetable waxes such as carnauba wax, ketones having a long-chain alkyl group such as distearyl ketone, silicones having an alkyl group, higher fatty acids such as stearic acid, long-chain aliphatic alcohols, and pentaerythritol (Partial) ester with long chain fatty acid, oleic acid , Higher fatty acid amides such as stearic acid amide or the like, can be used known ones.

In the present invention, among these, ketone compounds represented by the following general formula (I) are particularly preferred.

[0019]

Embedded image

[In the formula (I), R ¹ represents an alkyl group or an alkoxy group, and R ² represents an alkyl group or an alkylcarbonyloxyalkyl group. ]

Here, when R ² is an alkylcarbonyloxyalkyl group, R ¹ is preferably an alkoxy group, and the alkyl group of R ¹ and R ² has 10 or more carbon atoms. , Preferably 16 or more,
More preferably, it is 20 or more. As the alkylcarbonyloxyalkyl group for R ^2, the number of carbon atoms of the alkyl group in the alkylcarbonyloxy group is 10 or more, preferably 16 or more, more preferably 20 or more, and the carbonyloxyalkyl group Is preferably a linear alkyl group having 6 or more carbon atoms.

Specific examples of these ketone compounds include:
For example, aliphatic ketones such as di-n-decyl ketone, di-n-dodecyl ketone, di-n-stearyl ketone, di-n-eicosyl ketone, di-n-behenyl ketone, and di-n-tetracosyl ketone , Didosyl sebacate, distearyl sebacate, aliphatic diesters such as dibehenyl sebacate, stearyl laurate, behenyl laurate, stearyl stearate, behenyl stearate,
And aliphatic monoesters such as behenyl behenate. Among these, those having a half-value width of an endothermic peak measured by a differential scanning calorimeter (DSC) of 15 ° C. or less are particularly preferable.

The content of the wax in the resin composition for a toner is preferably 1 to 25 parts by weight, more preferably 5 to 15 parts by weight based on 100 parts by weight of the binder resin. preferable.

The resin composition for a toner according to the present invention may contain a charge controlling agent, if necessary.
As the charge control agent, for example, a nigrosine dye,
Positive charge control agents such as quaternary ammonium salt compounds, triphenylmethane compounds, imidazole compounds and polyamine resins, or azo dyes containing metals such as chromium, cobalt, aluminum and iron, salicylic acid or alkylsalicylic acid Use known metal salts and metal complexes such as chromium, zinc and aluminum, and metal salts and metal complexes of benzylic acid, amide compounds, phenol compounds, naphthol compounds, and negatively charged charge control agents such as phenolamide compounds. be able to.

Further, the resin composition for a toner according to the present invention further contains various known internal additives for the purpose of improving the adhesiveness, cohesiveness, fluidity, chargeability, surface resistance and the like of the toner. You may.

The toner for developing an electrostatic image of the present invention comprises a resin composition for toner containing at least the binder resin and the colorant, has a volume average particle size of 4 to 9 μm, and has a volume average particle size of 4 to 9 μm. It is essential that the ratio of the number of particles having a particle size of 40% or less to the total number of particles is not more than 9.0%, and the volume average particle size is preferably 5 to 8 μm,
It is more preferably 5 to 6 μm, and the ratio of the number of particles having a particle size of 40% or less of the volume average particle size to the total number of particles is preferably 6.0% or less, and 3.0%. It is more preferred that:

When the volume average particle size exceeds the above range, or when the ratio of the number of particles having a particle size of 40% or less of the volume average particle size to the total number of particles exceeds the above range, the resolution as a toner is reduced. When the volume average particle diameter is less than the above range, the fluidity of the toner decreases. The volume average particle size and the particle size distribution of the toner were measured with a Multisizer manufactured by Beckman Coulter, Inc.

The method for producing the toner for developing an electrostatic image of the present invention is not particularly limited. For example, the binder resin, the colorant, the wax, the charge control agent, etc. After uniformly mixing with a mixer such as a mixer, the mixture is melt-kneaded with a kneader such as a single-screw or twin-screw extruder to form a resin composition for toner, and then cooled and solidified, and then roughly pulverized by, for example, a feather mill or the like. Alternatively, after further coarsely pulverizing into coarse particles, the coarse particles are finely pulverized by, for example, a jet mill or the like, and the obtained powder is classified by, for example, a classifier such as an elbow jet to form toner particles having a specified particle size. Pulverization method, a suspension polymerization method in which the binder resin component monomer is subjected to suspension polymerization in the presence of the coloring agent, the wax, the charge control agent, and the like, and an emulsification polymerization of the binder resin component monomer. The emulsified mixture is stirred in the presence of the coloring agent, the wax, the charge control agent, and the like to aggregate (aggregate) emulsified particles. The polymerization method is preferred, and among them, the emulsion polymerization aggregation method is particularly preferred.

With respect to the emulsion polymerization coagulation method, preferred styrene resins are described in more detail.
Α-substituted alkylstyrene such as styrene, α-methylstyrene, α-ethylstyrene, m-methylstyrene, p
-Styrenes such as nuclear-substituted styrenes such as -methylstyrene and 2,5-dimethylstyrene, p-chlorostyrene, p-bromostyrene, and nucleus-substituted halogenated styrenes such as dibromostyrene alone or with those styrenes ,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth)
Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth)
Monofunctional acrylates such as acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, hexamethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate Pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ac Rate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, sorbitol tri ( Acrylates such as polyfunctional acrylates such as meth) acrylate, sorbitol tetra (meth) acrylate, sorbitol penta (meth) acrylate, and sorbitol hexa (meth) acrylate; or (meth) acrylic acid (in the above examples, "(Meth) acryl" means acryl and methacryl.)
And, in the presence of a polymerization initiator such as hydrogen peroxide, emulsion polymerization or copolymerization of a cationic, anionic, or nonionic surfactant or the like as an emulsifier, the resulting homopolymer or copolymer The toner particles are manufactured by aggregating (aggregating) the fine primary particles by stirring the emulsion of the above with the colorant, the wax, the charge control agent, and the like at a predetermined temperature with a disperser or the like. Is what you do.

Here, examples of the cationic surfactant as an emulsifier include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and the like. As anionic surfactants, for example, fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate and the like, and as nonionic surfactants, for example, dodecyl polyoxyethylene Ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan Roh oleate polyoxyethylene ethers, styryl phenyl polyoxyethylene ether, Monodekanoiru sucrose and the like, among these,
Anionic or nonionic surfactants are preferred.

The volume average particle diameter of the toner for developing an electrostatic image of the present invention and the ratio of the number of particles having a particle diameter of 40% or less of the volume average particle diameter to the total number of particles are determined by the emulsion polymerization in the above-mentioned production method. Type and amount of surfactant at the time, p at the time of aggregation
H, stirring conditions, the type and amount of an organic solvent, an inorganic salt, and the like used as needed during aggregation, and the aggregation time can be adjusted.

The toner for developing an electrostatic image of the present invention is usually prepared by adding an inorganic fine powder such as silica, alumina, titania or the like generally used for toner to the toner particles obtained by the above method. And uniformly mixed by a mixer such as a Henschel mixer, and the surface of the toner particles is coated with these inorganic fine powders. As the inorganic fine powder at that time, for example, those subjected to a surface treatment with a silane coupling agent or silicone oil are preferable, and the specific surface area is 5 to 500 m ² /
g is more preferred.

Further, the toner for developing an electrostatic image of the present invention is used for a magnetic two-component in which a magnetic powder such as ferrite or magnetite coexists as a carrier for transporting the toner to an electrostatic latent image portion by magnetic force; It is used for either a magnetic one-component in which the magnetic powder is contained in a toner or a non-magnetic one-component which does not use a magnetic powder in a toner, but is preferably used for a non-magnetic one-component or a magnetic one-component. Used.

[0034]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 In a glass reactor, 10 parts by weight of an ester wax emulsion containing behenyl behenate as a main component ("Unistar M2222SL" manufactured by NOF Corporation) as solids, and 0.4 parts of dodecylbenzenesulfonic acid were added. 400 parts by weight of deionized water and the amount of deionized water in the emulsion were added and heated to 90 ° C. under a nitrogen stream, and then 80 parts by weight of styrene, 20 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, 1 part by weight of bromomethane, 43 parts by weight of 2% aqueous hydrogen peroxide solution, and 4% of 2% aqueous ascorbic acid solution
3 parts by weight were charged, emulsion-copolymerized with stirring for 7 hours, and cooled to obtain a primary particle emulsion of a styrene-butyl acrylate-acrylic acid copolymer.

Next, 120 parts by weight of the primary particle emulsion as a solid content, 7 parts by weight of a blue dye phthalocyanine (manufactured by Dainichi Seika) and a charge control agent ("Bontron E-82" manufactured by Orient Chemical Co., Ltd. (5% dispersion)) Liquid)) as a solid content, and a mixture of 1 part by weight was heated to 70 ° C. while stirring with a disperser at pH 2.6 and maintained for 3 hours. Then, the pH was adjusted to 7, and the temperature was raised to 95 ° C. And held for 2 hours. The resulting slurry was cooled, filtered, washed with water,
The toner for developing an electrostatic charge image was obtained by drying with a blow dryer at 10 ° C. for 10 hours.

The volume average particle size and the particle size distribution of the obtained toner were measured using a multisizer manufactured by Beckman Coulter, Inc., and the volume average particle size and the particles having a volume average particle size of 40% or less were measured. The ratio of the number of particles having a diameter to the total number of particles was calculated, and the results are shown in Table 1.

Further, silica ("R972" manufactured by Nippon Aerosil Co., Ltd.) having a specific surface area of 110 m ² / g, which was surface-treated with a silane coupling agent, was added to the obtained toner.
A resolution chart for adding 0.6 parts by weight per part by weight and mixing the obtained toner with a Henschel mixer into a developing device of a laser printer, and repeatedly outputting black and white every other thin line of 1200 dpi, and , 120
Two types of resolution charts, which repeatedly output black and white and white for two lines of 0 dpi fine lines, were output, and the resolution of the chart was evaluated based on the following criteria. The results are shown in Table 1.

；: Fine lines are completely separated. Δ: Incomplete separation of fine lines. ×: fine lines are not separated.

Examples 2 to 9 and Comparative Examples 1 and 2 By changing the temperature and time for stirring and aggregating the primary particle emulsion obtained in Example 1, various volume average particle sizes shown in Table 1 were obtained. And a toner having a ratio of the number of particles having a particle diameter of 40% or less of the volume average particle diameter to the total number of particles is manufactured, and the resolution is evaluated in the same manner as in Example 1 using each of the obtained toners. The results are shown in Table 1.

[0041]

[Table 1]

[0042]

According to the present invention, it is possible to provide an electrostatic charge developing toner which can cope with high resolution and high gradation.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroki Furuya 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Chemical Research Institute (72) Inventor Hirofumi Nakayama 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Research Co., Ltd. Yokohama Research Laboratory F-term (reference) 2H005 AA01 AA06 AB03 AB06 CA04 CA14 CA30 EA05 EA07 FA06 FA07

Claims (6)

[Claims] 1. A toner resin composition comprising at least a binder resin and a colorant, and having a volume average particle size of 4 to 9 μm.
m, and the ratio of the number of particles having a particle diameter of 40% or less to the total number of particles having a particle diameter of 40% or less of the volume average particle diameter is 9.0% or less. 2. The electrostatic image developing toner according to claim 1, wherein the toner is obtained by aggregating fine particles by emulsion polymerization of a binder resin. 3. The electrostatic image developing toner according to claim 2, wherein the binder resin is a styrene- (meth) acrylate copolymer. 4. The resin composition for a toner according to the following general formula (I)
The toner for developing an electrostatic image according to any one of claims 1 to 3, further comprising a ketone compound represented by the following formula: Embedded image [In the formula (I), R ¹ represents an alkyl group or an alkoxy group, and R ² represents an alkyl group or an alkylcarbonyloxyalkyl group. ] 5. The electrostatic image developing toner according to claim 1, which is for a non-magnetic one component. 6. The toner for developing an electrostatic charge image according to claim 1, which is for a magnetic component.