JP2005157318A - Magnetic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic toner which gives stable image density without depending on the use environment and which has excellent low temperature fixing property, little deterioration in an image during fixing, high coloring power and less consumption of the toner. <P>SOLUTION: In the magnetic toner containing at least a binder resin and a magnetic material, the binder resin contains a polyester unit. The magnetic toner has 5.0 to 9.0 μm weight average particle size, 1.3 to 1.7 g/cm<SP>3</SP>absolute specific gravity, 20 to 35 Am<SP>2</SP>/kg saturation magnetization in a 796 kA/m magnetic field, and the dielectric tangent (tanδ) at 100 kHz satisfying (tanδ<SB>H</SB>-tanδ<SB>L</SB>)/tanδ<SB>L</SB>≤0.20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner used in a recording method using an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or a toner jet recording method.

  Conventional electrophotography uses a photoconductive substance to form an electrical latent image on a photoconductor by various means, and then develops the latent image with toner, such as paper if necessary. A method is known in which a toner image is transferred to a transfer material and then fixed by heating, pressing, heating and pressing, or solvent vapor to obtain a toner image.

  In the method of developing the toner, a magnetic one-component developing system using a magnetic toner is preferably used because it does not require a carrier and is advantageous in downsizing the apparatus. In the toner used for the magnetic one-component development system, a considerable amount of fine powdered magnetic material is mixed and dispersed, and this presence state greatly affects the fluidity and triboelectric charging property of the toner.

  In the case of reducing the particle size in order to improve dot reproducibility and the like in a magnetic toner, conventionally, in order to improve the balance between the charging characteristics and the magnetic characteristics, this is dealt with by increasing the amount of the magnetic material to be added. However, in this case, the following problems occur. For one, the binder component in the toner is relatively reduced, so that the low-temperature fixability is inhibited. Secondly, as the saturation magnetization amount and true specific gravity of the toner increase, the fluidity tends to decrease, and the spikes are likely to be formed in an aggregated state on the toner carrier. Becomes difficult. For this reason, the toner behaves as an aggregate during development on the latent image carrier. As a result, image quality deterioration such as a tailing phenomenon, image quality deterioration that causes an image to be crushed during fixing due to an increase in the amount of toner applied to the latent image, and an increase in consumption are likely to occur.

  In order to solve these problems, attempts have been made to control the dielectric properties of the toner in order to improve the developability of the magnetic toner. For example, a toner is known in which the dispersibility of the magnetic material is improved by adjusting the dielectric loss tangent (see, for example, Patent Document 1). However, in this case, there is an effect in stabilizing the charging characteristics in a certain environment. However, when the toner particle size is reduced or the amount of the magnetic material is reduced, the charging due to the environmental change and the change with time is required. Stabilization of characteristics is not sufficient.

  In addition, a technique is known in which the ratio of dielectric loss tangent in a high temperature region and a normal temperature region is specified to reduce a change in toner charging property due to the environment (see, for example, Patent Document 2). However, even in this case, it cannot be said that the environmental stability and the reduction in consumption of the magnetic toner are sufficient.

  In the one-component development system, charging is applied by passing toner through a gap between the developing sleeve and the regulating member. At this time, since the toner is subjected to great stress, the processing agent externally added to the toner base particles is buried in the toner base particles, detached from the toner base particles, or the toner base particles are missing, so-called toner deterioration. The problem also occurs. When such deterioration progresses, when it is used repeatedly, the charge amount decreases, or the generated fine powder adheres to the developing sleeve or the regulating member, so that an image defect due to charging failure easily occurs. In order to prevent such a phenomenon, an attempt has been made to improve the durability of the magnetic toner by making the toner spherical and improving the surface smoothness (see, for example, Patent Document 3). However, this method still has a problem in stabilizing charging characteristics due to environmental fluctuations.

Japanese Patent Laid-Open No. 10-221881 Japanese Patent Laid-Open No. 06-118700 Japanese Patent Laid-Open No. 11-295925

  An object of the present invention is to provide a toner that solves the above-described problems. Specifically, a magnetic toner capable of obtaining a stable image density regardless of the use environment, a magnetic toner having excellent low-temperature fixability, little image deterioration during fixing, high coloring power, and low toner consumption. The issue is to provide.

  The present inventors define the true specific gravity, magnetization amount, and dielectric characteristics of the toner, and further control the toner shape so that it has excellent low-temperature fixing and has stable charging characteristics over a long period of time regardless of the environment. The inventors have found that a toner can be obtained and have completed the present invention.

That is, the present invention is as follows.
(1) A magnetic toner containing magnetic toner base particles containing at least a binder resin and a magnetic material,
(I) the binder resin contains a polyester unit;
(Ii) The weight average particle diameter (D4) of the toner is 5.0 to 9.0 μm,
(Iii) the true specific gravity of the toner is 1.3 to 1.7 g / cm ³ ;
(Iv) the saturation magnetization of the toner at a magnetic field of 796 kA / m is 20 to 35 Am ² / kg;
(V) The toner contains 60% by number or more of toner having a circularity of 0.93 or more,
(Vi) A magnetic toner characterized in that a dielectric loss tangent (tan δ) at 100 kHz of the toner satisfies the following formula (1).

(Equation 1)
_{(Tanδ H -tanδ L) / tanδ} L ≦ 0.20 (1)
[Wherein, tan δ _H represents the dielectric loss tangent at the glass transition temperature (° C.) + 10 ° C. of the toner,
tan [delta _L represents the dielectric loss tangent of the glass transition temperature of the toner (℃) -10 ℃. ]
(2) The magnetic toner according to (1), wherein the toner contains 75% by number or more of toner having a circularity of 0.93 or more.
(3) The magnetic toner according to (1) or (2), wherein the toner has a dielectric loss tangent (tan δ) at 100 kHz and 40 ° C. of 2 × 10 ⁻³ to 1 × 10 ⁻² .
(4) The magnetic toner according to any one of (1) to (3), wherein the toner has a dielectric constant of 15 to 40 (pF / m) at 100 kHz and 40 ° C.
(5) The magnetic toner according to any one of (1) to (4), wherein the number average particle diameter of the magnetic material is 0.08 to 0.30 μm.
(6) The magnetic toner according to any one of (1) to (5), wherein a component having a molecular weight of 10,000 or less is contained in an amount of 30% by mass or more in the molecular weight distribution of the toner.
(7) The magnetic toner according to any one of (1) to (6), wherein the binder resin contains two or more resins having different softening points.
(8) The toner is externally added with inorganic fine powder, and the inorganic fine powder contains at least two kinds of metal oxides having a number average particle size of 100 nm or less. The magnetic toner according to any one of (7).
(9) At least a metal oxide (I) whose dielectric constant is 5 pF / m or more larger than the dielectric constant of the toner and a metal oxide (II) whose dielectric constant is 5 pF / m or smaller than the dielectric constant of the toner are contained. (8) The magnetic toner according to (8).

  According to the present invention, a magnetic toner capable of obtaining a stable image density regardless of the use environment, providing a low-temperature fixability, little image deterioration at the time of fixing, high coloring power, and low toner consumption are provided. can do.

  Hereinafter, the present invention will be described in detail.

The magnetic toner of the present invention is a magnetic toner containing magnetic toner base particles containing at least a binder resin and a magnetic material,
(I) the binder resin contains a polyester unit;
(Ii) The weight average particle diameter (D4) of the toner is 5.0 to 9.0 μm,
(Iii) the true specific gravity of the toner is 1.3 to 1.7 g / cm ³ ;
(Iv) the saturation magnetization of the toner at a magnetic field of 796 kA / m is 20 to 35 Am ² / kg;
(V) The toner contains 60% by number or more of toner having a circularity of 0.93 or more,
(Vi) The magnetic toner is characterized in that the dielectric loss tangent (tan δ) at 100 kHz of the toner satisfies the following formula (1).

(Equation 2)
_{(Tanδ H -tanδ L) / tanδ} L ≦ 0.20 (1)
[Wherein, tan δ _H represents the dielectric loss tangent at the glass transition temperature (° C.) + 10 ° C. of the toner,
tan [delta _L represents the dielectric loss tangent of the glass transition temperature of the toner (℃) -10 ℃. ]

  Conventionally, the value of dielectric loss tangent in a magnetic toner has been used as an index representing the ease of holding the charge amount. The lower this value, the higher the charge retention ability.

  On the other hand, in the present invention, the value of dielectric loss tangent is used as an index representing the stability of the charging characteristics of the toner in the electric field. In particular, as an index that quantitatively shows the rate of change in charging characteristics when the environment changes during the development process from the toner carrier to the latent image carrier, specifically, temperature, humidity, applied bias, etc., The value of dielectric loss tangent is used.

  The inventors' study has found that the rate of change in dielectric loss tangent before and after the glass transition temperature of the toner and the change in charging characteristics due to changes in the development environment show a high correlation. According to this, the value of dielectric loss tangent is mainly influenced by the dispersion state of the colorant in the toner, and particularly in the case of a magnetic toner, it is mainly affected by the dispersion state of the magnetic material. When compared with the same material, the value of the dielectric loss tangent becomes low by improving the dispersibility of the magnetic material. In addition, the value of the dielectric loss tangent tends to increase as the temperature rises, and this change increases as the amount of magnetic substance added decreases. This is presumably because the magnetic material content in the toner becomes relatively low, and the dispersion state of the magnetic material has a great influence on the charging characteristics. Therefore, in the present invention, the development stability index is used by using the change rate between the dielectric tangent in the normal state and the dielectric tangent in the weakly melted state, around the glass transition temperature of the toner.

  In the present invention, the dielectric loss tangent (tan δ) of the toner only needs to satisfy the above formula (1), and more preferably satisfies the following formula (2).

(Equation 3)
(Tan δ _{H −} tan δ _L ) / tan δ _L ≦ 0.15 (2)
[Wherein, tan δ _H represents the dielectric loss tangent at the glass transition temperature (° C.) + 10 ° C. of the toner,
tan [delta _L represents the dielectric loss tangent of the glass transition temperature of the toner (℃) -10 ℃. ]

  Here, the reason why the frequency is set to 100 kHz as a reference for measuring the dielectric loss tangent is that the frequency is suitable for verifying the dispersion state of the magnetic substance. When the frequency is lower than 100 kHz, since the influence of the glass transition temperature of the binder resin is increased, the rate of change of the dielectric loss tangent before and after the glass transition temperature becomes too large, making it difficult to determine the dispersion state of the magnetic substance. On the other hand, when the frequency is higher than 100 kHz, the change rate of the dielectric loss tangent becomes too small, and it becomes difficult to see the influence of the dispersibility of the magnetic material.

When the rate of change of dielectric loss tangent (tan δ _H −tan δ _L ) / tan δ _L is greater than 0.20, the charging characteristics of the toner are greatly affected by environmental fluctuations such as temperature, humidity, and development conditions. .20 or less is important.

  In order to control the change rate of the dielectric loss tangent, it is necessary to control the dispersion state of the magnetic substance in the toner. Specifically, the magnetic material is reduced in size, the particle size distribution of the magnetic material is controlled, the magnetic coagulation property is suppressed by performing a mechanical treatment after the magnetic material is synthesized, and the magnetic material is coated with an inorganic or organic material to flow. The improvement from a magnetic body, such as improving property, is mentioned. In addition, in the raw material mixing process at the time of toner production, improvements by the mixing process such as finer particle size of binder resin, release agent, etc., and longer mixing time can be mentioned. Furthermore, at the time of hot melt kneading, there are methods such as adjusting the kneading temperature to be higher than the softening point of the binder resin to control the viscosity of the melt, and adjusting the cooling method of the kneaded melt. Also, the above methods may be combined.

  In the present invention, it is preferable to control the shape of the toner in order to obtain a more stable charging ability. Several effects can be obtained by making the toner nearly spherical, that is, by increasing the circularity. For one thing, it is easy to obtain a uniform charge amount distribution, so that selective charge development associated with environmental fluctuations and repeated use can be reduced. Is possible. Furthermore, even when stress is applied between the developing sleeve and the regulating member in the magnetic one-component developing method, the amount of fine powder generated by pulverization is reduced, thereby suppressing contamination of the toner carrier by the fine powder. It becomes possible. By performing such shape control, it is possible to obtain a toner having more stable charging characteristics by achieving both the above-described dielectric characteristic control.

  In the present invention, it is possible to obtain the above-mentioned effect by allowing the toner to contain a certain number or more of 0.93 or more particles having relatively high circularity in the circularity distribution of the toner.

  In the present invention, it is preferable to contain 60% by number or more, more preferably 75% by number or more of toner in the range of 0.93 or more in the circularity distribution of the toner. When the amount is less than this range, a phenomenon such as a decrease in charge amount and contamination of the developing sleeve occurs during repeated use over a long period of time, and problems such as a decrease in image density tend to occur.

In the present invention, the true specific gravity of the magnetic toner is 1.3 to 1.7 g / cm ³ , and the saturation magnetization amount at a magnetic field of 796 kA / m is 20 to 35 Am ² / kg. When the true specific gravity is larger than 1.7 g / cm ³ or the saturation magnetization amount is larger than 35 Am ² / kg, in such a case, in many cases, the magnetic substance is actually contained in a relatively large amount. Therefore, an excessively large amount of toner is easily developed, and problems such as image deterioration during fixing and an increase in consumption occur, and low-temperature fixability also decreases. On the other hand, when the true specific gravity is less than 1.3 g / cm ³ or the saturation magnetization is less than 20 Am ² / kg, in such a case, the content of the magnetic material is often small, The ear-forming ability of the rice is too low, and the image quality is likely to deteriorate. In addition, the rate of change of dielectric loss tangent becomes too large, and the change in charging characteristics due to the environment becomes large.

  In the toner of the present invention, the content of the magnetic material is preferably 25 to 70 parts by mass, more preferably 45 to 65 parts by mass with respect to 100 parts by mass of the binder resin.

  Further, the magnetic toner of the present invention has a weight average particle diameter (D4) adjusted to 5.0 to 9.0 μm in order to faithfully develop minute latent image dots and achieve high image quality. In a toner having a weight average particle diameter of less than 5.0 μm, the amount of magnetic powder contained in one toner particle is decreased, which causes an increase in fog and is not preferable. On the other hand, when the weight average particle diameter of the toner exceeds 9.0 μm, since the reproduction of one dot is deteriorated, it tends to be difficult to achieve high image quality.

  In the present invention, the binder resin is a resin containing a polyester unit. Examples of the resin containing a polyester unit include a polyester resin and a hybrid resin in which a polyester unit and a styrene-acrylic resin unit are chemically bonded. A mixture of these resins and other resins can also be used as the binder resin.

  The polyester resin is originally excellent in sharp melt property and advantageous in terms of low-temperature fixability, and also has excellent dispersibility of the magnetic substance in the hot melt kneading process during toner production. Further, the dielectric constant of the toner can be made relatively high, and is a suitable resin for controlling the dielectric characteristics in the present invention.

  The polyester resin is a resin produced by polycondensation of a polyhydric alcohol and a polybasic acid, and examples of the monomer of the polyester resin component include the following.

  Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives represented by the following formula (i), and diols represented by the following formula (ii): Can be mentioned.

  Divalent carboxylic acids include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, or the like. An succinic acid substituted with an alkyl group or an alkenyl group having 6 to 18 carbon atoms or an anhydride thereof; an unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, itaconic acid, or an anhydride thereof; Can be mentioned.

  Other monomers of the polyester resin include glycerin, pentaerythritol, sorbit, sorbitan, and polyhydric alcohols such as oxyalkylene ethers of novolak type phenol resins; trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid And polyhydric carboxylic acids such as anhydride thereof.

  In the hybrid resin, as a monomer for generating the polyester unit, an acid or an alcohol component that can be used when generating the polyester resin can be used, and vinyl for generating a styrene-acrylic resin component can be used. Examples of the system monomer include the following.

  Styrene monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert. -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chloro styrene, 3 Styrene such as 1,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene and derivatives thereof.

Examples of acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid-n-butyl, acrylic acid isobutyl, acrylic acid-n-octyl, acrylic acid dodecyl, acrylic acid-2- Acrylic acid and acrylic esters such as ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, -n-butyl methacrylate, methacrylic acid Such as isobutyl acid, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate And α- methylene aliphatic monocarboxylic acids and esters thereof, acrylonitrile, methacrylonitrile, and the like such as acrylic acid or methacrylic acid derivatives of acrylamide.

  Furthermore, as a monomer which produces | generates a styrene-acrylic-type resin unit, acrylic acid or methacrylic acid esters, such as 2-hydroxyl ethyl acrylate, 2-hydroxyl ethyl methacrylate, 2-hydroxyl propyl methacrylate, 4- (1-hydroxy-1) And monomers having a hydroxyl group such as (methylbutyl) styrene and 4- (1-hydroxy-1-methylhexyl) styrene.

  In the styrene-acrylic resin unit, various monomers capable of vinyl polymerization can be used in combination as required. Such monomers include ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; halogenated compounds such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride. Vinyls; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether: vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl compounds such as N-vinyl pyrrolidone; vinyl naphthalenes; maleic acid, citraconic acid, itaconic acid, a Unsaturated dibasic acids such as kenyl succinic acid, fumaric acid and mesaconic acid; unsaturated dibasic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride; methyl half maleate Esters, ethyl maleate half ester, butyl maleate half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, alkenyl succinic acid methyl half ester, fumarate methyl half ester Unsaturated basic acid esters such as mesaconic acid methyl half ester; Unsaturated basic acid esters such as dimethylmaleic acid and dimethylfumaric acid; α, β-unsaturated such as acrylic acid, methacrylic acid, crotonic acid and cinnamic acid Acid Anhydrides; anhydrides of the α, β-unsaturated acids and lower fatty acids; and monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof. It is done.

Moreover, the said styrene-acrylic-type resin unit may be bridge | crosslinked with the crosslinkable monomer which is illustrated below as needed. Crosslinkable monomers include, for example, aromatic divinyl compounds, diacrylate compounds linked by alkyl chains, diacrylate compounds linked by alkyl chains containing ether bonds, and chains containing aromatic groups and ether bonds. And diacrylate compounds, polyester-type diacrylates, and polyfunctional crosslinking agents. Here, examples of the aromatic divinyl compound include divinylbenzene and divinylnaphthalene. Examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6- Examples include hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate. Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, and dipropylene. Examples include glycol diacrylate and those obtained by replacing acrylate of the above compound with methacrylate. Examples of diacrylate compounds linked by a chain containing an aromatic group and an ether bond include polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4)- Examples include 2,2-bis (4-hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate. Examples of polyester diacrylates include trade name MANDA (Nippon Kayaku). Examples of the polyfunctional cross-linking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing acrylates of the above compounds with methacrylate; And allyl cyanurate and triallyl trimellitate.

  These crosslinkable monomers can be used in an amount of 0.01 to 10% by mass (more preferably 0.03 to 5% by mass) with respect to 100% by mass of other monomer components. Among these cross-linkable monomers, those which are preferably used from the viewpoint of fixability and offset resistance are aromatic divinyl compounds (particularly divinylbenzene) and divalent groups connected by a chain containing an aromatic group and an ether bond. Examples include acrylate compounds.

  The styrene-acrylic resin unit may be a resin unit manufactured using a polymerization initiator. Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 , 4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1,1′-azobis (1-cyclohexanecarbonitrile), 2-carbamoylazoisobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2′-azobis ( 2-methylpropane), methylethylketone peroxide, acetylacetone peroxide, ketone peroxide such as cyclohexanone peroxide 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-Butylcumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5 5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2- D Xylethylperoxycarbonate, dimethoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneodecanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butylperoxyisopropylcarbonate, di-t -Butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy-2-ethyl hexanoate, di-t-butyl peroxy hexahydroterephthalate, di-t-butyl peroxya Rate, and the like.

  The hybrid resin is a resin in which a polyester unit and a styrene-acrylic resin unit are directly or indirectly chemically bonded, and the above-mentioned polyester resin component, styrene-acrylic resin component, and these resin components Consists of monomer components that can react with both. Examples of the monomer constituting the polyester unit that can react with the styrene-acrylic resin unit include unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof.

Among the monomers constituting the styrene-acrylic resin unit, those capable of reacting with the polyester resin unit include those having a carboxyl group or a hydroxyl group, and acrylic acid or methacrylic acid esters.

  As a method for obtaining a hybrid resin, a polymer containing a monomer component capable of reacting with each of the above-described polyester resin and styrene-acrylic resin is present, and either or both of the resins are polymerized. The method obtained by this is preferable.

  In the present invention, when a hybrid resin is used as the binder resin, the polyester unit is preferably contained in the hybrid resin in an amount of 60% by mass or more, and preferably 80% by mass or more.

  In the present invention, the polyester resin and / or the hybrid resin contains a resin crosslinked with a trivalent or higher polyvalent carboxylic acid and / or a trivalent or higher polyhydric alcohol. It is preferable to achieve both.

  Moreover, in this invention, it is good to contain 30 mass% or more of low molecular weight components with a molecular weight of 10,000 or less. In the present invention, two or more polyester resins or hybrid resins having different softening points may be mixed in order to control the dispersibility of the magnetic material.

  In the present invention, it is preferable from the viewpoint of the dispersibility of the magnetic substance in the toner base particles that the binder resin charged in the raw material mixing step during production has a number average particle size of 300 μm or less.

  As the magnetic material used in the toner of the present invention, a conventionally known magnetic material is used. Examples of magnetic materials contained in the magnetic toner include iron oxides such as magnetite, maghemite, and ferrite, and iron oxides including other metal oxides; metals such as Fe, Co, Ni, or these metals and Al, Co, Cu , Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, alloys with metals such as Se, Ti, W, and V; and mixtures thereof.

Specifically, iron trioxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O ₄ ), iron yttrium oxide (Y ₃ Fe ₅ O ₁₂ ), Cadmium iron oxide (CdFe ₂
O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), copper iron oxide (CuFe ₂ O ₄ ), lead iron oxide (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), neodymium iron oxide ( NdFe ₂ O ₃ ), iron barium oxide (BaFe ₁₂ O ₁₉ ), iron magnesium oxide (MgFe ₂ O ₄ ), iron oxide manganese (MnFe ₂ O ₄ ), iron lanthanum oxide (LaFeO ₃ ), iron powder (Fe), Examples thereof include cobalt powder (Co) and nickel powder (Ni). In the present invention, at least magnetic iron is contained as a magnetic material, and one or two or more other metals can be arbitrarily selected and used as necessary.

The magnetic characteristics of these magnetic materials under application of 796 kA / m (10 k Oersted) are as follows: the coercive force is 1.5 kA / m to 12 kA / m, and the saturation magnetization is 50 to 200 Am ² / kg (preferably 50 to 100 Am ² / kg). ), Preferably having a remanent magnetization of ² to 20 Am ² / kg. The magnetic properties of the magnetic material can be measured using a vibration type magnetometer such as VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) under the conditions of 25 ° C. and an external magnetic field of 796 kA / m.

  In the magnetic toner of the present invention, it is preferable to use a fine powder of magnetic iron oxide such as iron trioxide or γ-iron trioxide as a magnetic material.

In the present invention, the toner has a saturation magnetization of 20 to 35 Am ^{2 at} a magnetic field of 796 kA / m.
The magnetic properties and addition amount of the magnetic material may be controlled so as to be / kg.

  In the present invention, the number average particle diameter of the magnetic material is preferably 0.08 μm to 0.30 μm. When the thickness is less than 0.08 μm, the magnetic material itself becomes reddish, and the color of the toner also increases redness, and the fine dispersion in the binder resin deteriorates, thereby controlling the rate of change of dielectric loss tangent. It becomes difficult to do. On the other hand, if it exceeds 0.30 μm, the coloring power of the toner is reduced, and when the magnetic substance content is low, the rate of change of the dielectric loss tangent increases, and the dielectric loss tangent can be controlled so as to satisfy the above formula (1). It becomes difficult.

  In the present invention, it is preferable that a different metal such as silicon, zinc or titanium is contained in and / or on the surface of the magnetic material. This is because the magnetic cohesiveness can be reduced and the dispersibility of the magnetic substance in the toner can be improved.

  Moreover, it is preferable that the magnetic body of the present invention reduces the magnetic cohesive force by applying mechanical shear in the slurry state after the synthesis of the magnetic body. This is because by performing such processing, the fine dispersibility at the time of toner production is dramatically improved.

  In the present invention, other colorants may be contained as required. As the colorant, one or more of carbon black and other known pigments and dyes can be used.

  In the present invention, other additives may be added to the toner particles as necessary. As such other additives, various additives known to be added to the inside of toner particles can be used, and examples thereof include a release agent and a charge control agent.

  Examples of the release agent include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof. Polymers; waxes mainly composed of fatty acid esters such as carnauba wax, sazol wax, and montanic acid ester wax; deoxidized part or all of fatty acid esters such as deoxidized carnauba wax; palmitic acid , Saturated linear fatty acids such as stearic acid and montanic acid; unsaturated fatty acids such as brandic acid, eleostearic acid and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, melyl alcohol Saturated alcohols such as alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide Saturated fatty acid bisamides such as hexamethylenebisstearic acid amide; ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, etc. Unsaturated fatty acid amides; aromatic bisamides such as m-xylene bis-stearic acid amide and N, N′-distearylisophthalic acid amide; aliphatic metals such as calcium stearate, calcium furate, zinc stearate and magnesium stearate Salt (one Waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; partial esters of fatty acids and polyhydric alcohols such as behenic acid monoglycerides A methyl ester compound having a hydroxyl group obtained by hydrogenation of vegetable oil or the like; a long-chain alkyl alcohol or a long-chain alkyl carboxylic acid having 12 or more carbon atoms; and the like.

Examples of the release agent particularly preferably used in the present invention include aliphatic hydrocarbon waxes. As such an aliphatic hydrocarbon wax, for example, a low molecular weight alkylene polymer obtained by radical polymerization of alkylene at a high pressure or a Ziegler catalyst at a low pressure; a high molecular weight alkylene polymer is thermally decomposed. Alkylene polymers obtained; synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained by the age method from synthesis gas containing carbon monoxide and hydrogen, and synthetic hydrocarbon waxes obtained by hydrogenating them; these aliphatics And hydrocarbon waxes separated by press sweating, solvent method, vacuum distillation and fractional crystallization.

  Examples of the hydrocarbon as the base of the aliphatic hydrocarbon wax include those synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, Hydrocarbon compounds synthesized by the Gintor method and Hydrocol method (using a fluidized catalyst bed); Up to several hundred carbon atoms can be obtained by the Age method (using an identified catalyst bed) in which many waxy hydrocarbons are obtained Hydrocarbons; hydrocarbons obtained by polymerizing alkylene such as ethylene with a Ziegler catalyst. Among such hydrocarbons, in the present invention, it is preferable that the hydrocarbon is a linear hydrocarbon having a small number of branches and a long saturation, and particularly a hydrocarbon synthesized by a method not based on polymerization of alkylene has a molecular weight distribution. Is also preferable.

  In the present invention, the release agent is contained in the toner particles so that when the toner particles containing the release agent are measured with a differential scanning calorimeter, an endothermic main peak appears in the region of 70 to 140 ° C. in the obtained DSC curve. It is preferable from the viewpoint of low-temperature fixability and high-temperature offset resistance of the toner.

  The endothermic peak temperature can be measured according to ASTM D3418-82 using a highly accurate internal heat input compensation type differential scanning calorimeter, for example, DSC-7 manufactured by PerkinElmer, Inc. The appearing temperature can be adjusted by using a release agent in which the melting point, glass transition point, polymerization degree, and the like are appropriately adjusted. The DSC-7 is applied to the measurement of the temperature indicating the thermal properties of the toner particles and the toner particle material such as the glass transition point of the binder resin, the softening point, and the melting point of the wax in addition to the peak temperature. Can do.

  Specific examples of the wax that can be used as a release agent in the present invention include Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), high wax 400P, 200P. , 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals), Sazol H1, H2, C80, C105, C77 (Schumann Sazol), HNP-1, HNP-3, HNP-9, HNP -10, HNP-11, HNP-12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 ( Toyo Petrolite), wood wax, beeswax, rice wax, candelilla wax, carnauba wax Available), and the like by the Corporation Cerarica NODA.

  The release agent is preferably contained in the toner particles at a ratio of 2 to 15 parts by mass per 100 parts by mass of the binder resin from the viewpoint of fixability and charging characteristics.

  In the toner of the present invention, a charge control agent can be used as described above in order to stabilize the charging property. Although the charge control agent varies depending on the type of charge control agent and the physical properties of other toner particle constituent materials, it is generally preferable that the toner base particle contains 0.1 to 10 parts by mass per 100 parts by mass of the binder resin. More preferably, 0.1 to 5 parts by mass are contained. As such charge control agents, there are known ones for controlling the toner to be negatively charged and those for controlling the toner to be positively charged. One or two kinds of various kinds of charge control agents are used depending on the kind and use of the toner. The above can be used.

For controlling the toner to be negatively charged, for example, an organometallic complex and a chelate compound are effective. Examples thereof include a monoazo metal complex; an acetylacetone metal complex; a metal complex of aromatic hydroxycarboxylic acid or aromatic dicarboxylic acid; A metal salt. In addition, examples of the toner that controls the toner to be negatively charged include aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenol; Examples of toners that can be positively charged include, for example, modified products of nigrosine and fatty acid metal salts; quaternary ammoniums such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. Salts, and onium salts such as phosphonium salts and analogs thereof, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (including phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, Tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound, etc.); metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate Dioctyl tin borate, diorgano tin borate such as dicyclohexyl tin borate; and the like. In the present invention, these can be used alone or in combination. Among them, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used for controlling the toner to be positively charged.

  More specifically, for negative charging, for example, Spiron Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-84. , E-88, E-89 (Orient Chemical Co., Ltd.) are more preferable, and for positive charging, for example, TP-302, TP-415 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) N-01, N-04, N-07, P-51 (Orient Chemical Co.) and Copy Blue PR (Clariant) are preferable.

  The toner of the present invention is preferably a negatively chargeable charge control agent from the viewpoint of the physical properties of the toner material. In particular, an azo-based iron complex such as T-77 is dispersible with the binder resin and the magnetic material. From this point, it is preferably used.

The toner of the present invention preferably has a dielectric loss tangent (tan δ) measured at a frequency of 100 kHz in the range of 2 × 10 ⁻³ to 1 × 10 ⁻² . When the dielectric loss tangent is within this range, the dispersibility of the magnetic substance in the toner becomes good, and it becomes easy to suppress fluctuations in charging characteristics due to the environment. Furthermore, in the present invention, it is preferable that the dielectric constant of the toner at a frequency of 100 kHz at 40 ° C. is 15 to 40 (pF / m).

  Thus, by controlling the value of dielectric loss tangent and dielectric constant, the charging stability can be dramatically improved. When the dielectric constant is less than 15 pF / m, the charge amount of the toner becomes too high, and it becomes difficult to have stable image characteristics in a low humidity environment. On the other hand, when the dielectric constant is greater than 40 pF / m, the toner charge rises slowly and the charge amount is likely to decrease when the toner is left unattended.

  The toner of the present invention is preferably used with various materials added depending on the type of toner.

  Examples of the external additive include a fluidity improver that improves the fluidity of the toner, such as inorganic fine powder, and a conductive fine powder that adjusts the chargeability of the toner, such as metal oxide fine particles. Examples include external additives.

Examples of the fluidity improver include those that can improve the fluidity of the toner by external addition to the toner particles. Examples of such fluidity improvers include fluorine resin powders such as fine vinylidene fluoride powder and polytetrafluoroethylene fine powder; fine powder silica such as wet process silica and dry process silica, fine powder titanium oxide, and fine powder. Alumina; treated silica, surface treated with silane coupling agent, titanium coupling agent, silicone oil, etc., treated titanium oxide, treated alumina; and the like.

  In the present invention, the external additives as described above can be used, but those having a number average particle diameter of 100 nm or less and containing at least two kinds of metal oxides are preferably used. Furthermore, it is more preferable to contain a metal oxide (I) whose dielectric constant is 5 pF / m or more larger than that of the toner and a metal oxide (II) whose dielectric constant is 5 pF / m or more smaller than that of the toner.

  When the number average particle diameter is larger than 100 nm, the particles are easily released from the toner surface, and the effect of the present invention is hardly obtained. Further, when the dielectric constant of the metal oxide (I) is only less than 5 pF / m as compared with the toner, toner aggregation is promoted by electrostatic attraction between toner particles, and dot reproducibility tends to deteriorate. is there. When the dielectric constant of the metal oxide (II) is only smaller than that of the toner by less than 5 pF / m, the image density tends to decrease due to a decrease in charging. The BET specific surface area of the metal oxide (II) is preferably 1.3 to 10 times the BET specific surface area of the metal oxide (I). Within this range, the external additive having a high dielectric constant significantly reduces the electric field concentrated between the toner particles, and the toner coverage by the external additive having a low dielectric constant is improved. This is because a toner exhibiting sufficient effects can be obtained.

  Titanium oxide fine particles are preferably used when the number average particle diameter is 100 nm or less and the dielectric constant is 5 pF / m or more larger than that of the toner. Furthermore, among the titanium oxide fine particles, fine particles having a dielectric constant of 40 pF / m or more, more preferably 100 pF / m or more are preferable because they have a remarkable effect of reducing electrostatic aggregation in an electric field.

  As the titanium oxide fine particles used in the present invention, titanium oxide fine particles obtained by low-temperature oxidation (thermal decomposition, hydrolysis) of sulfuric acid method, chlorine method, volatile titanium compounds such as titanium alkoxide, titanium halide, and titanium acetylacetonate are used. It is done. As the crystal system, any of anatase type, rutile type, mixed crystal type thereof, and amorphous type can be used.

Furthermore, the titanium oxide fine particles used in the present invention have good results when the specific surface area by nitrogen adsorption measured by the BET method is 10 m ² / g or more, preferably 30 m ² / g or more. When the BET specific surface area is smaller than 10 m ² / g, the fluidity of the toner is lowered and the titanium oxide fine particles are easily released from the toner particles, so that a large amount of the free titanium oxide fine particles remain in the developing machine, It is not preferable because it adheres to various devices in the forming apparatus main body and promotes deterioration of image quality.

Moreover, it is preferable that the hydrophobic titanium oxide fine particles used in the present invention have a volume resistance value of 10 ⁸ Ω · cm or more. When the volume resistance value is less than 10 ⁸ Ω · cm, titanium oxide acts as a leakage site for charging, causing a significant decrease in charge amount, resulting in fog and deterioration in image quality.

  The titanium oxide fine particles used as the metal oxide (I) may be mixed at 0.01 to 5 parts by mass with respect to 100 parts by mass of the toner base particles. When the content is less than 0.01 parts by mass, it is difficult to obtain the effect of suppressing electrostatic aggregation. When the content exceeds 5 parts by mass, the fluidity of the toner tends to be excessively high, and uniform charging may be inhibited.

Although the manufacturing method of the hydrophobized titanium oxide fine particle which can be used in this invention is illustrated below, this invention is not restrict | limited in particular to these methods.
(A) Slurry metatitanic acid is generated by hydrolyzing a fraction solution obtained by decomposing this with sulfuric acid using ilmenite as a starting material. After adjusting the pH of this slurry of metatitanic acid, a hydrophobizing agent is added dropwise and reacted while being sufficiently dispersed in a hydrogen medium so that coalescence of metatitanic acid particles does not occur in the slurry. This is filtered, dried, and crushed to produce hydrophobized titanium oxide fine particles.
(B) Using titanium tetraisopropoxide as a raw material, using a chemical pump to reduce the amount little by little, using nitrogen gas as a carrier gas, sending it to glass wool of a vaporizer heated to about 200 ° C. and evaporating it. In the reactor, after instantaneous thermal decomposition at about 300 ° C., rapid cooling is performed to collect the product. This is further baked at about 300 ° C. for about 2 hours, and further subjected to a hydrophobic treatment to produce hydrophobic titanium oxide fine particles.

  In the present invention, the use of titanium oxide fine particles that have been subjected to the hydrophobization treatment as described above increases the affinity with the resin. Therefore, when the titanium oxide fine particles are externally added, fixing to the toner surface is facilitated, and static This is preferable because the effect of suppressing electrocoagulation is easily exhibited.

  Examples of the hydrophobizing agents that can be used for the titanium oxide fine particles include coupling agents such as silane coupling agents, titanate coupling agents, aluminum coupling agents, and zircoaluminate coupling agents.

  As said silane coupling agent, what is represented by the following general formula is mentioned, for example.

(Chemical formula 3)
R _m SiY _n
[In the formula, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents an alkyl group, a vinyl group, a phenyl group, a methacryl group, an amino group, an epoxy group, a mercapto group, or a derivative thereof. , N represents an integer of 1 to 3. ]

  Specifically, for example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethyl Examples include methoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

  The treatment amount of the hydrophobizing agent is preferably 1 to 60 parts by mass, more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the titanium oxide fine particles.

  Particularly suitable silane coupling agents in the present invention are alkylalkoxysilane coupling agents represented by the following general formula.

(Chemical formula 4)
_{C n H 2n + 1 -Si- (} OC m H 2m + 1) 3
[Wherein, n represents an integer of 4 to 12, and m represents an integer of 1 to 3. ]

In the above alkylalkoxysilane coupling agent, when n is smaller than 4, treatment is easy, but the degree of hydrophobicity is low, which is not preferable. When n is larger than 12, the hydrophobicity is sufficient, but the coalescence of the titanium oxide fine particles increases, the fluidity tends to decrease, and the image quality may be adversely affected. When m is larger than 3, the reactivity of the alkylalkoxysilane coupling agent is lowered and hydrophobicity cannot be satisfactorily performed. As for a more preferable alkyl alkoxysilane coupling agent, n is 4-8 and m is 1-2.

  The treatment amount of the alkylalkoxysilane coupling agent represented by the above general formula is also preferably 1 to 60 parts by mass, more preferably 3 to 50 parts by mass, with respect to 100 parts by mass of the titanium oxide fine particles, similarly to the above-described treatment amount. Part.

  The hydrophobizing treatment may be performed with one type of hydrophobizing agent alone, or two or more types of hydrophobizing agents may be used. For example, one type of coupling agent may be subjected to a hydrophobic treatment alone, or two types of coupling agents may be used simultaneously or after a hydrophobic treatment with a coupling agent, followed by further hydrophobic treatment with another coupling agent. Processing may be performed.

There are the following methods for hydrophobizing titanium oxide fine particles using a hydrophobizing agent, but the present invention is not particularly limited to these methods.
(A) As a hydrophobization treatment by a wet method, a predetermined amount of a hydrophobizing agent or a dilute solution thereof or a mixture thereof while sufficiently stirring mechanically in a dispersion of a predetermined amount of metatitanic acid fine particles or titanium oxide fine particles The liquid is added and further mixed and stirred so that the particles do not coalesce. After thorough mixing and stirring, dry and crush.
(B) As an example of a hydrophobization treatment method by dry method, first, a predetermined amount of hydrophobizing agent or a diluting solution or a mixture thereof is added dropwise or sprayed while stirring a predetermined amount of titanium oxide fine particles with a device such as a blender. Mix well with stirring. Thereafter, a predetermined amount of a hydrophobizing agent or diluent or a mixed solution thereof is further added and sufficiently mixed and stirred. The resulting mixture is then heated and dried. Thereafter, the mixture is crushed by stirring with an apparatus such as a blender.

  As a material having a number average particle diameter of 100 nm or less and a dielectric constant smaller than that of the toner by 5 pF / m or more, a substance having a low dielectric constant such as alumina or silica fine particles can be used. In particular, silica fine particles have a desired dielectric constant and are excellent in charging stability of the toner, and therefore are preferably used for the toner of the present invention. Examples of the silica fine particles include fine powder silica such as wet process silica and dry process silica, and treated silica obtained by surface-treating these silicas with a silane coupling agent, a titanium coupling agent, silicone oil, or the like. Further, preferred silica fine particles include what is called dry process silica or fumed silica produced by vapor phase oxidation of a silicon halogen compound, and are produced by a conventionally known technique. For example, it utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is represented by the following formula.

(Chemical formula 5)
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

  In this production process, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride or titanium chloride together with silicon halogen compounds. Include. The average particle size is preferably in the range of 0.001 to 2 μm, and particularly preferably, silica fine powder in the range of 0.002 to 0.2 μm is used.

  Furthermore, it is preferable to use treated silica fine particles obtained by hydrophobizing silica fine particles produced by vapor phase oxidation of the silicon halide compound.

As a hydrophobizing method, it is applied by chemical treatment with an organosilicon compound that reacts or physically adsorbs with silica fine particles. As a preferred method, silica fine particles produced by vapor phase oxidation of a silicon halogen compound are treated with an organosilicon compound. Examples of such organosilicon compounds include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, Bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxy Silane, diphenyldiethoxysilane, 1-hexamethyldisiloxane, 1,3-divinyltetramethyldisilo Xanthan and the like. These are used alone or in a mixture of two or more.

  In addition, aminopropyltrimethoxysilane having nitrogen atom, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyl Trimethoxysilane, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine Such silane coupling agents may be used alone or in combination. A preferred silane coupling agent is hexamethyldisilazane (HMDS).

  The silica fine particles may be treated with silicone oil or may be treated together with the hydrophobizing agent.

  Preferred silicone oils are those having a viscosity at 25 ° C. of 30 to 1000 centistokes, such as dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil. Etc. are preferred.

  As a method for treating the silicone oil, for example, a method in which silica fine particles treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer; a method in which the silicone oil is sprayed on the base silica fine particles Or a method of dissolving or dispersing silicone oil in a suitable solvent and then adding silica fine particles and mixing to remove the solvent. More preferably, the silicone oil-treated silica is heated to 200 ° C. or higher (more preferably 250 ° C. or higher) in an inert gas after the silicone oil is treated to stabilize the surface coating.

  Moreover, in the external additive of this invention, it is preferable that the addition amount of metal oxide (I) is 0.1 to 10 times the addition amount of metal oxide (II). When the ratio is less than 0.1 times, a substance having a low dielectric constant becomes excessive, and the toner is likely to be charged up, so that both dots and fog tend to deteriorate. If it exceeds 10 times, the chargeability of the toner is lowered, and the toner density on the image density and latent image becomes insufficient.

  Further, an external additive other than the above-mentioned inorganic fine powder may be added to the toner of the present invention as required, and it is preferable to use 0.1 to 5 parts by mass with respect to 100 parts by mass of the toner. .

Examples of such external additives include, but are not limited to, charging aids, conductivity-imparting agents, fluidity-imparting agents, anti-caking agents, mold release agents, lubricants, abrasives, etc. Examples include fine particles. More specifically, for example, a lubricant such as Teflon (registered trademark), zinc stearate, and polyvinylidene fluoride, preferably polyvinylidene fluoride is preferable. Alternatively, an abrasive such as cerium oxide, silicon carbide, strontium titanate, etc., among which strontium titanate is preferable. Alternatively, a fluidity-imparting agent such as aluminum oxide, particularly a hydrophobic one is preferably mentioned. Alternatively, an anti-caking agent, a conductivity imparting agent such as carbon black, zinc oxide, antimony oxide, and tin oxide, or fine particles with reverse polarity can be used.

  The production method of the toner of the present invention is not particularly limited, but the binder resin, magnetic material, and, if necessary, other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, By melting, kneading and kneading using a heat kneader such as an extruder to make the resins compatible with each other, cooling and solidifying the molten kneaded product, and then crushing the solidified product and classifying the crushed product A method of obtaining toner mother particles is preferred. The toner base particles and the external additive can be obtained by sufficiently mixing them as necessary with a mixer such as a Henschel mixer.

  In producing the toner of the present invention, the classification can be performed at any time after the generation of the toner base particles. For example, the classification may be performed after mixing with the external additive.

  Examples of devices that can be generally used as toner manufacturing devices are listed below, but are not limited thereto. Table 1 shows an example of a pulverizing device for toner production, Table 2 shows an example of a classification device for toner production, Table 3 shows an example of a sieve device for toner production, and Table 4 shows an example of a mixing device for toner production. Table 5 gives examples of kneading apparatuses for toner production.

In the present invention, in order to control the circularity of the toner, the toner is preferably pulverized by applying a mechanical impact force. Examples of the treatment that gives mechanical impact force include a method using a mechanical pulverizer such as a pulverizer KTM manufactured by Kawasaki Heavy Industries, Ltd., a turbo mill manufactured by Turbo Industrial Co., Ltd., a mechano-fusion system manufactured by Hosokawa Micron Corporation, The method of processing with apparatuses, such as a manufactured hybridization system, is mentioned. These apparatuses can be used as they are or after being appropriately improved. By controlling the conditions for applying such a mechanical impact, the circularity of the toner can be controlled.
The toner of the present invention can be adjusted in circularity by using a specific processing device that brings the shape of the toner particles closer to a sphere. An apparatus capable of spheroidizing suitable for the toner of the present invention will be specifically described with reference to the drawings.

  FIG. 1 shows an example of a surface modification apparatus used in the present invention.

  The surface modifying apparatus shown in FIG. 1 is a classification means for separating a casing 15, a jacket (not shown) through which cooling water or antifreeze liquid can be passed, and particles larger than a predetermined particle size and fine particles having a predetermined particle size or less. A classifying rotor 1, a dispersion rotor 6 which is a surface treatment means for applying a mechanical impact to the particles to treat the surface of the particles, and a predetermined interval with respect to the outer periphery of the dispersion rotor 6. Of the particles divided by the classification rotor 1, the guide ring 9 that is a guide means for guiding particles larger than a predetermined particle size among the particles divided by the classification rotor 1, and the particles divided by the classification rotor 1 The fine powder collection discharge port 2 is a discharge means for discharging fine particles having a predetermined particle size or less to the outside of the apparatus, and cold air introduction is a particle circulation means for sending particles whose surface is treated by the dispersion rotor 6 to the classification rotor 1. Mouth 5 and processed A raw material supply port 3 for introducing the child into the casing 15, the powder discharge port 7 and a closable discharge valve 8 for discharging the treated surface particles from the casing 15 inside.

  The classification rotor 1 is a cylindrical rotor and is provided on one end face side in the casing 15. The fine powder collection outlet 2 is provided at one end of the casing 15 so as to discharge particles inside the classification rotor 1. The raw material supply port 3 is provided at the center of the peripheral surface of the casing 15. The cold air introduction port 5 is provided on the other end surface side of the peripheral surface of the casing 15. The powder discharge port 7 is provided at a position facing the raw material supply port 3 on the peripheral surface of the casing 15. The discharge valve 8 is a valve that freely opens and closes the powder discharge port 7. A dispersion rotor 6 and a liner 4 are provided between the cold air introduction port 5 and the raw material supply port 3 and the powder discharge port 7. The liner 4 is provided along the inner peripheral surface of the casing 15. As shown in FIG. 2, the dispersion rotor 6 includes a disk and a plurality of rectangular disks 10 arranged along the normal line of the disk at the periphery of the disk. The dispersion rotor 6 is provided on the other end surface side of the casing 15 and is provided at a position where a predetermined interval is formed between the liner 4 and the square disk 10. A guide ring 9 is provided at the center of the casing 15. The guide ring 9 is a cylindrical body and is provided so as to extend from a position covering a part of the outer peripheral surface of the classification rotor 1 to the vicinity of the classification rotor 6. The guide ring 9 includes a first space 11 that is a space between the outer peripheral surface of the guide ring 9 and the inner peripheral surface of the casing 15 in the casing 15, and a second space that is a space inside the guide ring 9. A space 12 is formed.

  The dispersion rotor 6 may have a cylindrical pin instead of the square disk 10. In the present embodiment, the liner 4 is provided with a large number of grooves on the surface facing the square disk 10, but may have no grooves on the surface. Moreover, the installation direction of the classification rotor 1 may be vertical as shown in FIG. 1 or horizontal. Further, the number of classification rotors 1 may be single or multiple as shown in FIG.

In the surface reforming apparatus configured as described above, when a certain amount of finely pulverized product is introduced from the raw material supply port 3 with the discharge valve 8 closed, the charged finely pulverized product is first blower (not shown). And is classified by the classifying rotor 1. At that time, the classified fine powder having a predetermined particle size or less passes through the peripheral surface of the classification rotor 1, is guided to the inside of the classification rotor 1, and is continuously discharged and removed out of the apparatus. Coarse powder having a predetermined particle diameter or more is applied to a circulating flow generated by the dispersion rotor 6 along the inner periphery (second space 12) of the guide ring 9 due to centrifugal force, and the gap between the square disk 10 and the liner 4 ( Hereinafter, it is also referred to as “surface modification zone”. The powder guided to the surface modification zone is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor 6 and the liner 4. The surface-modified particles having undergone surface modification are transported to the classification rotor 1 along the outer periphery (first space 11) of the guide ring 9 on the cold air passing through the machine. Is discharged to the outside of the machine, and the coarse powder is circulated into the second space 12 again and repeatedly subjected to the surface modification action in the surface modification zone. As described above, in the surface modification apparatus shown in FIG. 1, the classification of particles by the classification rotor 1 and the treatment of the surface of particles by the dispersion rotor 6 are repeated. After a certain period of time, the discharge valve 8 is opened and the surface modified particles are recovered from the discharge port 7.

  In such an apparatus, there is almost no exudation of the release agent due to heat, and the exudation of the release agent to the surface of the toner particles due to the emergence of a new surface as compared with the above-described system that gives a mechanical impact force. This is very preferable because it makes it easy to adjust the spheroidization of toner particles and the exudation of the release agent.

  A method for measuring physical properties of the toner of the present invention is as follows. Examples described later are also based on this method.

(1) Dielectric constant and dielectric loss tangent of toner and inorganic fine powder The dielectric constant of the magnetic toner according to the present invention is measured by the following method. 1 g of the magnetic toner is weighed, and a load of 19600 kPa (200 kg / cm ² ) is applied for 2 minutes to form a disk-shaped measurement sample having a diameter of 25 mm and a thickness of 1 mm or less (preferably 0.5 to 0.9 mm). This measurement sample is mounted on an ARES (Rheometric Scientific F.E.) equipped with a dielectric constant measuring jig (electrode) having a diameter of 25 mm, heated to a temperature of 80 ° C. and melt-fixed. Thereafter, the toner is cooled to a temperature of 40 ° C., and a dielectric constant of the toner is measured by measuring a frequency range of 500 to ⁵ × 10 ⁵ Hz under a load of 1.47 N (150 g).
The dielectric constant of the inorganic fine powder according to the present invention is measured by the following method. 1 g of inorganic fine powder is weighed and molded into a disk-shaped measurement sample having a diameter of 25 mm and a thickness of 1 mm or less (preferably 0.5 to 0.9 mm) over a period of 2 minutes under a load of 19600 kPa (200 kg / cm ² ). . This measurement sample is mounted on ARES (manufactured by Rheometric Scientific F.E.) equipped with a dielectric constant measuring jig (electrode) having a diameter of 25 mm, and the temperature is fixed at 40 ° C. to 1.47 N (150 g). ), The dielectric constant of the inorganic fine powder is measured by measuring a frequency range of 500 to ⁵ × 10 ⁵ Hz.

(2) Measurement of weight average particle diameter (D4) of toner The particle size distribution can be measured by various methods, but in the present invention, it is performed using a multisizer of a Coulter counter.
The measuring device is a Coulter Counter Multisizer II (manufactured by Coulter), connected to an interface (manufactured by Nikkiki) that outputs number distribution and volume distribution, and a computer for analysis. The electrolyte is a special grade or first grade sodium chloride. Is used to prepare a 1% NaCl aqueous solution. As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the above electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and when measuring the toner particle size as an aperture with the above-mentioned Coulter Counter Multisizer II, use a 100 μm aperture. To do. The volume and number of toner are measured to calculate the volume distribution and the number distribution. Then, the weight average particle diameter (D4) is determined.

(3) Measurement of True Specific Gravity of Toner As a method of measuring the true specific gravity of the magnetic toner according to the present invention, a gas displacement type measurement method using helium is adopted. As a measuring instrument, Accupic 1330 (manufactured by Shimadzu Corporation) is used. In the measurement method, 4 g of a measurement sample is put into a stainless steel cell having an inner diameter of 18.5 mm, a length of 39.5 mm, and a capacity of 10 cm ³ . Next, the volume of the magnetic toner in the sample cell is measured by changing the pressure of helium, and the density of the magnetic toner is determined from the determined volume and the weight of the sample.

(4) Saturation magnetization measurement of toner The saturation magnetization of the magnetic toner is measured using a vibration magnetometer VSMP-1-10 (manufactured by Toei Kogyo Co., Ltd.) at a room temperature of 25 ° C. and an external magnetic field of 796 kA / m.

(5) Measurement of magnetic particle size The average particle size of the magnetic material is measured using a laser diffraction particle size distribution meter (manufactured by Horiba, Ltd.).

(6) Method for measuring softening point of binder resin The softening point of the binder resin is measured by a descent-type flow tester according to the measurement method described in JIS K7210. A specific measurement method is shown below.
While a 1 cm ³ sample was heated at a heating rate of 6 ° C./min using a descent flow tester (manufactured by Shimadzu Corporation), a load of 1960 N / m ² (20 kg / cm ² ) was applied by a plunger, and the diameter was 1 mm. Then, a nozzle having a length of 1 mm is pushed out, thereby drawing a plunger descending amount (flow value) -temperature curve, where the height of the S-shaped curve is h, the temperature relative to h / 2 (half of the resin is The temperature that flows out) is taken as the softening point.

(7) Measurement of molecular weight distribution of toner The molecular weight of the chromatogram by GPC is measured under the following conditions.
The column is stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml / min. The sample is dissolved in THF, filtered through a 0.2 μm filter, and the filtrate is used as a sample. Measurement is performed by injecting 50 to 200 μl of a THF sample solution adjusted to a sample concentration of 0.05 to 0.6% by weight. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Or a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3 manufactured by Toyo Soda Kogyo Co., Ltd. .9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4. It is appropriate to use 48 × 10 ⁶ and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, a combination of μ-styragel 500, 10 ³ , 10 ⁴ , 10 ⁵ manufactured by Waters, or shodex KA-801, 802 manufactured by Showa Denko KK , 803, 804, 805, 806, 807 are preferred.

(8) Measurement of glass transition temperature of binder resin and toner Using a differential scanning calorimeter (DSC measuring apparatus) and DSC-7 (manufactured by Perkin Elmer), measurement is performed according to ASTM D3418-82.
The measurement sample is precisely weighed in an amount of 2 to 10 mg, preferably 5 mg. This is put in an aluminum pan, an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 10 ° C./min at a temperature rise rate of 10 ° C./min. In this temperature raising process, an endothermic peak of the main peak of the DSC curve in the range of 40 to 100 ° C. is obtained. The intersection of the midpoint of the baseline before and after the endothermic main peak and the differential heat curve is defined as the glass transition temperature in the present invention.

(9) Measurement of the circularity of the toner The circularity of the toner is measured using a flow type particle image measuring device “FPIA-2100 type” (manufactured by Sysmex Corporation), and is calculated using the following equation.

  Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define. The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). The circularity in the present invention is an index indicating the degree of unevenness of the toner particles, and indicates 1.00 when the toner particles are perfectly spherical. The more complicated the surface shape, the smaller the circularity.

  As a specific measuring method, 10 ml of ion-exchanged water from which impure solids have been removed in advance is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, followed by further measurement. Add 0.02 g of sample and disperse uniformly. As a means for dispersion, an ultrasonic disperser “Tetora 150 type” (manufactured by Nikka Ki Bios Co., Ltd.) is used, and dispersion treatment is performed for 2 minutes to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more. In order to suppress variation in circularity, the installation environment of the apparatus is controlled at 23 ° C. ± 0.5 ° C. so that the temperature inside the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C. Preferably, autofocus is performed using 2 μm latex particles every 2 hours.

  To measure the circularity of the toner, the flow type particle image measuring device is used, the concentration of the dispersion is readjusted so that the toner concentration at the time of measurement is 3000 to 10,000 / μl, and 1000 or more toners are measured. To do. After the measurement, the circularity of the toner is obtained using this data.

  Furthermore, “FPIA-2100”, which is a measuring apparatus used in the present invention, improves the magnification of the processed particle image as compared with “FPIA-1000” conventionally used for calculating the shape of the toner. Furthermore, the accuracy of toner shape measurement has been improved by improving the processing resolution of the captured image (256 × 256 → 512 × 512), thereby achieving more reliable capture of the particle shape.

(10) The average particle size of the inorganic fine powder according to the present invention is measured using a transmission electron microscope. That is, an inorganic fine powder sample is observed with a transmission electron microscope, and 100 particle diameters in a visual field are measured to obtain an average particle diameter.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
(Binder Resin Production Example 1)

Terephthalic acid 27mol%
Adipic acid 15 mol%
Trimellitic acid 6mol%
Bisphenol derivative represented by the formula (i) 35 mol%
(Propylene oxide 2.5 mol adduct)
17 mol% of bisphenol derivative represented by the formula (i)
(Ethylene oxide 2.5 mol adduct)

  The acid component and alcohol component shown above, and tin 2-ethylhexanoate as an esterification catalyst were charged into a four-necked flask and equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device, and nitrogen The reaction was performed by raising the temperature to 230 ° C. in an atmosphere. After completion of the reaction, the product was taken out of the container, cooled and pulverized to obtain a resin A having a softening point of 143 ° C. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

next,
Terephthalic acid 24mol%
Adipic acid 16mol%
Trimellitic acid 10mol%
30 mol% of bisphenol derivative represented by the formula (i)
(Propylene oxide 2.5 mol adduct)
Bisphenol derivative represented by the formula (i) 20 mol%
(Ethylene oxide 2.5 mol adduct)

  The acid component and alcohol component shown above and the esterification catalyst are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device are attached, and the temperature is maintained at 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature. After completion of the reaction, the product was taken out of the container, cooled and pulverized to obtain a resin B having a softening point of 98 ° C. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

  50 parts by mass of each of the resins A and B were mixed with a Henschel mixer to obtain a binder resin 1.

This binder resin 1 had a glass transition temperature of 59 ° C. and a softening point of 128 ° C., and contained 43% by mass of a component having a molecular weight of 10,000 or less in gel permeation chromatography.
(Binder Resin Production Example 2)

Terephthalic acid 30mol%
Dodecenyl succinic acid 12mol%
Trimellitic acid 6mol%
Bisphenol derivative represented by the formula (i) 35 mol%
(Propylene oxide 2.5 mol adduct)
17 mol% of bisphenol derivative represented by the formula (i)
(Ethylene oxide 2.5 mol adduct)

  The acid component and alcohol component shown above and the esterification catalyst are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device are attached, and the temperature is maintained at 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature. After completion of the reaction, the product was taken out of the container, cooled and pulverized to obtain a resin C having a softening point of 143 ° C. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

next,
Terephthalic acid 26mol%
Dodecenyl succinic acid 10mol%
Trimellitic acid 10mol%
Bisphenol derivative represented by the formula (i) 32 mol%
(Propylene oxide 2.5 mol adduct)
22 mol% of bisphenol derivative represented by the formula (i)
(Ethylene oxide 2.5 mol adduct)

  The acid component and alcohol component shown above and the esterification catalyst are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device are attached, and the temperature is maintained at 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature. After completion of the reaction, the product was taken out of the container, cooled and pulverized to obtain a resin D having a softening point of 98 ° C. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

  Resin C70 mass part and resin D30 mass part were mixed with the Henschel mixer, and it was set as binder resin 2.

  This binder resin 2 had a glass transition temperature of 57 ° C. and a softening point of 135 ° C., and contained 33% of a component having a molecular weight of 10,000 or less in gel permeation chromatography. (Binder Resin Production Example 3)

Terephthalic acid 25mol%
Fumaric acid 10mol%
Dodecenyl succinic acid 8mol%
Trimellitic acid 6mol%
30 mol% of bisphenol derivative represented by the formula (i)
(Propylene oxide 2.5 mol adduct)
Bisphenol derivative represented by the formula (i) 21 mol%
(Ethylene oxide 2.5 mol adduct)

  The acid component and alcohol component shown above and the esterification catalyst are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device are attached, and the temperature is maintained at 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature. After completion of the reaction, the product was taken out from the container, cooled and pulverized to obtain a binder resin 3. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

  This binder resin 3 had a glass transition temperature of 62 ° C. and a softening point of 130 ° C., and contained 28% of a component having a molecular weight of 10,000 or less in gel permeation chromatography. (Binder Resin Production Example 4)

Terephthalic acid 25mol%
Dodecenyl succinic acid 15mol%
Trimellitic acid 8mol%
Bisphenol derivative represented by the formula (i) 32 mol%
(Propylene oxide 2.5 mol adduct)
Bisphenol derivative represented by the formula (i) 20 mol%
(Ethylene oxide 2.5 mol adduct)

  As a monomer for producing a polyester unit, the above-mentioned acid component, alcohol component and catalyst, 2-ethylhexanoic acid tin are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device. For producing 100% by mass of the monomer component for producing the above-mentioned polyester unit while producing the styrene-acrylic resin unit shown below while stirring the apparatus at a temperature of 130 ° C. in a nitrogen atmosphere. What mixed 25 mass parts of monomers with the polymerization initiator (benzoyl peroxide) was dripped over 4 hours from the dropping funnel.

83% by mass of styrene
2-ethylhexyl acrylate 15% by mass
Acrylic acid 2% by mass

  This was aged for 3 hours while maintaining the temperature at 130 ° C., and the temperature was raised to 230 ° C. to carry out the reaction. After completion of the reaction, the product is taken out from the container and pulverized, and contains a polyester resin component, a vinyl polymer component, and a hybrid resin component in which the polyester unit and the styrene-acrylic resin unit are chemically bonded, and softens. A resin E having a point of 132 ° C. was obtained. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

next,
Terephthalic acid 28mol%
Dodecenyl succinic acid 12mol%
Trimellitic acid 4mol%
30 mol% of bisphenol derivative represented by the formula (i)
(Propylene oxide 2.5 mol adduct)
26 mol% of bisphenol derivative represented by the formula (i)
(Ethylene oxide 2.5 mol adduct)

  As a monomer for producing a polyester unit, the above-mentioned acid component, alcohol component and catalyst, 2-ethylhexanoic acid tin are charged into a four-necked flask, and a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device. A monomer for producing the styrene-acrylic resin unit shown below with respect to 100 parts by mass of the monomer component for producing the polyester unit while stirring the apparatus at a temperature of 130 ° C. in a nitrogen atmosphere. What mixed 25 mass parts with the polymerization initiator (benzoyl peroxide) was dripped over 4 hours from the dropping funnel.

83% by mass of styrene
2-ethylhexyl acrylate 15% by mass
Acrylic acid 2% by mass

  This was aged for 3 hours while maintaining the temperature at 130 ° C., and the temperature was raised to 230 ° C. to carry out the reaction. After completion of the reaction, the product is taken out from the container and pulverized to contain a polyester resin component, a vinyl polymer component, and a hybrid resin component in which a polyester unit and a styrene-acrylic resin unit are chemically bonded, and softening A resin F having a point of 100 ° C. was obtained. At this time, the pulverization conditions were adjusted so that the number average particle diameter was 200 μm.

  60 parts by mass of resin E and 40 parts by mass of resin F were mixed with a Henschel mixer to obtain a binder resin 4.

This binder resin 4 had a glass transition temperature of 60 ° C. and a softening point of 129 ° C., and contained 38% by mass of a component having a molecular weight of 10,000 or less in gel permeation chromatography.
(Binder Resin Production Example 5)

Styrene 82 parts by mass Butyl acrylate 18 parts by mass Monobutyl maleate 0.5 parts by mass Di-tert-butyl peroxide 2 parts by mass

  The monomer composition was mixed with 200 parts by mass of xylene raised to the reflux temperature. The solution polymerization was completed in 6 hours under reflux of xylene to obtain a low molecular weight resin solution. On the other hand, the following monomer composition was mixed, suspended and dispersed in 200 parts by mass of deaerated water and 0.2 part by mass of polyvinyl alcohol.

Styrene 68 parts by mass Butyl acrylate 26 parts by mass Monobutyl maleate 6 parts by mass Benzoyl peroxide 0.1 parts by mass

  This suspension dispersion was heated and held at 80 ° C. for 24 hours under a nitrogen atmosphere to complete the polymerization, dehydrated and dried to obtain a high molecular weight resin.

23 parts by mass of this high molecular weight resin was put into the above-mentioned low molecular weight resin solution (containing 77 parts by mass of resin), dissolved completely in the solution and mixed, and then subjected to vacuum distillation at a high temperature (180 ° C.). The solvent was removed to obtain the target styrene copolymer composition.
(Magnetic substance production example 1)

  An aqueous solution mainly composed of a ferrous salt containing zinc is prepared so that a mass ratio Zn / Fe of zinc to iron is 0.005, and an aqueous sodium hydroxide solution equivalent to or more than iron and zinc is added to the aqueous solution. Are mixed to obtain a ferrous hydroxide slurry. The pH of this ferrous hydroxide slurry is maintained at 12, and an oxidation reaction is performed at 80 ° C. The obtained slurry containing magnetite particles was subjected to dispersion treatment by applying mechanical shearing force, and then filtered, washed, dried and pulverized to obtain a magnetic body 1.

The obtained magnetic body 1 had a number average particle diameter of 0.12 μm, magnetic characteristics at a magnetic field of 796 kA / m, saturation magnetization of 89 Am ² / kg, residual magnetization of 11 Am ² / kg, and coercive force of 12 kA / m.
(Magnetic substance production example 2)

  An aqueous solution containing a ferrous salt containing titanium as a main component so that the mass ratio Ti / Fe of titanium to iron is 0.008, and an aqueous sodium hydroxide solution equivalent to or more than iron and titanium in this aqueous solution. Are mixed to obtain a ferrous hydroxide slurry. The pH of this ferrous hydroxide slurry is maintained at 12, and an oxidation reaction is performed at 80 ° C. The obtained slurry containing magnetite particles was subjected to dispersion treatment by applying mechanical shearing force, and then filtered, washed, dried and pulverized to obtain a magnetic body 2.

The obtained magnetic body 2 had a number average particle diameter of 0.25 μm, magnetic characteristics at a magnetic field of 796 kA / m, saturation magnetization of 82 Am ² / kg, residual magnetization of 10 Am ² / kg, and coercive force of 12 kA / m.
(Magnetic substance production example 3)

  A magnetic body 3 was obtained in the same manner except that in the magnetic body production example 2, the dispersion treatment for the slurry containing magnetite particles after the oxidation reaction was not performed.

The obtained magnetic material 3 had a number average particle diameter of 0.25 μm, magnetic characteristics at a magnetic field of 796 kA / m, saturation magnetization of 82 Am ² / kg, residual magnetization of 10 Am ² / kg, and coercive force of 12 kA / m.
(Magnetic substance production example 4)

  An aqueous solution containing a ferrous salt containing silicon as a main component so that the mass ratio Si / Fe of silicon to iron is 0.008, and an aqueous sodium hydroxide solution equivalent to or more than iron and silicon is added to the aqueous solution. Are mixed to obtain a ferrous hydroxide slurry. The pH of this ferrous hydroxide slurry is maintained at 12, and an oxidation reaction is performed at 80 ° C. The obtained slurry containing magnetite particles was subjected to dispersion treatment by applying mechanical shearing force, and then filtered, washed, dried, and pulverized to obtain a magnetic body 4.

The obtained magnetic body 4 had a number average particle diameter of 0.08 μm, magnetic characteristics at a magnetic field of 796 kA / m, saturation magnetization of 86 Am ² / kg, residual magnetization of 12 Am ² / kg, and coercive force of 12 kA / m.
(Magnetic substance production example 5)

  A sodium hydroxide aqueous solution equal to or more than iron in an aqueous solution containing a ferrous salt as a main component is mixed to obtain a ferrous hydroxide slurry. The pH of this ferrous hydroxide slurry is maintained at 12, and an oxidation reaction is performed at 80 ° C. The obtained slurry containing magnetite particles was filtered, washed, dried and pulverized to obtain a magnetic body 5.

The obtained magnetic material 5 had a number average particle diameter of 0.33 μm, magnetic characteristics at a magnetic field of 796 kA / m, saturation magnetization of 78 Am ² / kg, residual magnetization of 8 Am ² / kg, and coercive force of 9 kA / m. <Example 1>

Binder resin 1 100 parts by mass Magnetic substance 1 50 parts by mass T-77 (Azo-based iron compound, manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by mass Polyethylene wax (Sazol, C105, melting point 105 ° C.)
3 parts by mass

  The above raw materials are mixed with a Henschel mixer for 3 minutes, melt-kneaded with a twin screw extruder PCM-30 heated to 160 ° C, cooled with a cooling belt (cooling water 15 ° C), and then the mixture is coarsely pulverized with a hammer mill. did. The coarsely pulverized product was finely pulverized with a turbo mill (manufactured by Turbo Kogyo Co., Ltd.), and the obtained finely pulverized product was classified with an air classifier to obtain magnetic toner base particles.

To 100 parts by mass of the magnetic toner base particles, 1.2 parts by mass of hydrophobic dry silica (BET 180 m ² / g) was externally added using a Henschel mixer, and as shown in Table 6 below, a weight average particle size of 7.0 μm, circular A magnetic toner 1 containing 62.3% of particles having a degree of 0.93 or more was obtained.

The magnetic toner 1 had a glass transition temperature of 59 ° C., a true specific gravity of 1.56 g / cm ³ , and a saturation magnetization of 28 Am ² / kg. From the dielectric constant measurement at 100 kHz, the tan δ at 40 ° C. was 6 × 10 ⁻³ , the dielectric constant was 35 pF / m, and the rate of change of tan δ at the glass transition temperature ± 10 ° C. was 0.07. .
(Evaluation of magnetic toner)

A commercially available Canon digital copying machine IR6010 was used, the process speed was changed from 265 mm / s to 320 mm / s, and modification was performed so that 75 sheets of A4 horizontal size could be passed per minute. As a result of this modification, when continuous paper feeding is performed, both the temperature inside the machine and the temperature near the developing device are likely to rise. In this state, using the toner 1 of the present invention, a durability test of 100,000 sheets was performed in a low temperature and low humidity environment (temperature 15 ° C., humidity 10%). Thereafter, an additional 100,000 sheet passing durability test was conducted in a high temperature and high humidity environment (temperature 30 ° C., humidity 80%). Thereafter, in a room temperature and normal humidity environment (temperature 23 ° C., humidity 50%), 300,000 sheets were further passed through. The original used a chart with an image ratio of 5%. Evaluation on images was performed as follows. Separately, image deterioration during fixing, toner consumption measurement, and fixing property evaluation were also performed as follows.

The results of each evaluation are shown in Table 7. As a result, good results were obtained as shown in Table 7.
<Image evaluation>
1. Image density

The image density is evaluated by comparing the reflection density of the 5mm circle (1.1 density) of the chart before and after the endurance test in each environment using an SPI filter with a Macbeth densitometer (Macbeth). did.
2. Sharpness of digital images

  A manuscript including lines and letters was used, and images after the durability test under each environment were evaluated according to the following criteria using visual observation and a magnification microscope.

A: Both character images and line images are faithfully reproduced in detail.
B: Although some disturbance or scattering has occurred in the details, it is a level at which there is no problem with visual observation.
C: It is a level where disturbance and scattering can be seen even visually.
D: Many disturbances and scattering occur, and the original is not reproduced.
<Image deterioration due to fixing>

  In a normal temperature and humidity environment, the initial potential of paper passing durability is adjusted to adjust the potential difference between the latent image carrier and the toner carrier, and an image with a width of 150 μm is obtained as an image before fixing. This image was fixed by an external power source with an IR6010 fixing device removed and an external fixing device attached with an external drive, and the change rate of the line width after fixing was judged according to the following criteria.

A: The rate of change is 5% or less, and the image is hardly deteriorated.
B: The change rate is 5 to 10%, and deterioration of the image is not visually confirmed.
C: The rate of change is 10 to 20%, and deterioration of the image can be visually confirmed.
D: The rate of change is 20% or more, and image deterioration is severe.
<Toner consumption>

  In an image formation test under a normal temperature and humidity environment, the toner consumption was calculated from the initial developing device mass and the developing device mass after outputting 2000 sheets by the following formula.

(Equation 5)
(Toner consumption)
= {(Initial developer mass)-(Developer mass after output of 2000 sheets)} / 2000 <Fixability evaluation>

  IR6010 was installed in a low-temperature and low-humidity environment, and the input power source was changed from 100V, which is a normal setting voltage, to 80V by a stabilized power source. In this state, 1000 sheets of originals (A3 size) with an image ratio of 5% were continuously passed. In this evaluation, the fixability is evaluated by performing continuous image output under conditions where the fixing roller temperature is lowered such that the input voltage is lower than the normal setting and the paper is continuously passed.

A: No offset is observed during 1000 sheets.
B: A slight offset is observed between 800 and 1000 sheets.
C: An offset is seen between 500 and 800 sheets.
D: An offset is seen up to 500 sheets.
<Examples 2 to 7>

  The magnetic toners 2 to 2 shown in Table 6 were used in the same manner as in Example 1 except that the type, addition amount, and toner particle size of the binder resin and magnetic material in Example 1 were changed as shown in Table 6. 7 was obtained.

The obtained magnetic toners 2 to 7 were evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 8>

  In Example 7, magnetic toner 8 was obtained using the same method as in Example 7 except that the raw material mixing time at the time of toner production was changed from 3 minutes to 1 minute. By shortening the raw material mixing time, a toner was obtained under conditions where the dispersibility of the material became severe.

The obtained magnetic toner 8 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 9>

  In Example 7, a magnetic toner 9 was obtained using the same method as in Example 7 except that the kneading temperature at the time of toner production was changed from 160 ° C. to 130 ° C. By lowering the kneading temperature, the toner was obtained in a state where the dispersibility of the magnetic material was severer by kneading with the resin having a high melt viscosity.

The obtained magnetic toner 9 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 10>

  In the production of the binder resin 2, the magnetic toner 10 was used in the same manner as in Example 7 except that the resin particle size of both resins when mixing the resin C and the resin D with a Henschel mixer was changed from 200 μm to 400 μm. Got.

The obtained magnetic toner 10 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 11>

  In Example 7, the magnetic toner 11 was obtained using the same method as in Example 7 except that the binder resin used was changed to the binder resin 3.

The obtained magnetic toner 11 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 12>

  In Example 7, a magnetic toner 12 was obtained using the same method as in Example 7 except that the binder resin used was changed to the binder resin 4.

The obtained magnetic toner 12 was evaluated in the same manner as in Example 1 above. As a result, good results as shown in Table 7 were obtained.
<Example 13>
The finely pulverized product obtained in Example 1 was treated with a processing apparatus as shown in FIGS. 1 and 2, and while removing fine particles at a classification rotor rotational speed of 120 s ⁻¹ , a dispersion rotor rotational speed of 100 s ⁻¹ (rotational circumference) Surface treatment was performed at a speed of 130 m / sec) for 45 seconds (after the finely pulverized product was charged from the raw material supply port 3, after 45 seconds of treatment, the discharge valve 8 was opened and the product was taken out as a treated product). At that time, ten square disks were installed on the top of the dispersion rotor 6, the distance between the guide ring 9 and the upper square disk on the dispersion rotor 6 was 30 mm, and the distance between the dispersion rotor 6 and the liner 4 was 5 mm. The blower air volume was 14 m ³ / min, the temperature of the refrigerant passed through the jacket and the cold air temperature T1 were set to −20 ° C. to obtain magnetic toner mother particles.

To 100 parts by mass of the magnetic toner base particles, 1.2 parts by mass of hydrophobic dry silica (BET 180 m ² / g) is externally added by a Henschel mixer, and particles having a weight average particle size of 7.0 μm and a circularity of 0.93 or more. Was obtained as a magnetic toner 13.

The magnetic toner 13 had a glass transition temperature of 59 ° C., a true specific gravity of 1.56 g / cm ³ , and a saturation magnetization of 28 Am ² / kg. From the dielectric constant measurement at 100 kHz, t at 40 ° C.
an δ was 6 × 10 ⁻³ , and the tan δ change rate at a glass transition temperature ± 10 was 0.07.

The obtained magnetic toner 13 was evaluated in the same manner as in Example 1 above. As a result, good results as shown in Table 7 were obtained.
<Examples 14 to 16>

  The magnetic toners 14 to 14 shown in Table 6 were used in the same manner as in Example 13 except that the type, addition amount, and toner particle size of the binder resin and magnetic material in Example 13 were changed as shown in Table 6. 16 was obtained.

The obtained magnetic toners 14 to 16 were evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 17>

  In Example 7, a magnetic toner 17 was obtained in the same manner as in Example 7 except that the inorganic fine powder added externally was changed to the following two types of metal oxides.

Hydrophobic dry silica (BET; 180 m ² / g, dielectric constant: 5) 1.0 part by mass Rutile titanium oxide surface-treated with i-C ₄ H ₉ Si (OCH ₃ ) ₃
(BET 90 m ² / g, dielectric constant; 118) 0.2 parts by mass

The obtained magnetic toner 17 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Example 18>

  In Example 7, a magnetic toner 18 was obtained using the same method as in Example 7 except that the inorganic fine powder added externally was changed to the following two metal oxides.

Hydrophobic dry silica (BET; 180 m ² / g, dielectric constant; 5) 1.0 part by mass Anatase-type titanium oxide surface-treated with i-C ₄ H ₉ Si (OCH ₃ ) ₃
(BET 100 m ² / g, dielectric constant; 48) 0.2 parts by mass

The obtained magnetic toner 18 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Comparative example 1>

Binder resin 2 100 parts by mass Magnetic material 5 50 parts by mass T-77 (Hodogaya Chemical Co., Ltd.) 2 parts by mass Polyethylene wax (Sazol Co., C105, melting point 105 ° C.)
5 parts by mass

  The above raw materials were mixed with a Henschel mixer for 1 minute, then melt kneaded with a biaxial extruder PCM-30 heated to 130 ° C., and the cooled mixture was coarsely pulverized with a hammer mill. The coarsely pulverized product was finely pulverized with a turbo mill (manufactured by Turbo Kogyo Co., Ltd.), and the obtained finely pulverized product was classified with an air classifier to obtain magnetic toner base particles.

To 100 parts by mass of the magnetic toner base particles, 1.2 parts by mass of hydrophobic dry silica (BET 180 m ² / g) was externally added by a Henschel mixer, and as shown in Table 6, a comparative toner having a weight average particle diameter of 7.5 μm. 1 was obtained.

The obtained comparative toner 1 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Comparative example 2>

  In Example 7, the toner was changed to the binder resin 5 to obtain a comparative toner 2.

The obtained comparative toner 2 was evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Comparative Examples 3-4>

  Comparative toners 3 and 3 shown in Table 6 were used in the same manner as in Comparative Example 1 except that the types, addition amounts, and toner particle sizes of the binder resin and magnetic material in Comparative Example 1 were changed as shown in Table 6. 4 was obtained.

The obtained comparative toners 3 to 4 were evaluated in the same manner as in Example 1 above. As a result, the results shown in Table 7 were obtained.
<Comparative Example 5>

  Comparative toner 5 shown in Table 6 was obtained in the same manner as in Example 7 except that fine pulverization was performed with a PJM jet pulverizer (Nippon Pneumatic Industry).

  The obtained comparative toner 5 was evaluated in the same manner as in Example 1. As a result, the results shown in Table 7 were obtained.

The schematic sectional drawing of the surface modification apparatus used by this invention is shown. The schematic diagram seen from the upper surface of the dispersion | distribution rotor in FIG. 1 is shown.

Claims (9)

A magnetic toner containing magnetic toner base particles containing at least a binder resin and a magnetic material,
(I) the binder resin contains a polyester unit;
(Ii) The weight average particle diameter (D4) of the toner is 5.0 to 9.0 μm,
(Iii) the true specific gravity of the toner is 1.3 to 1.7 g / cm ³ ;
(Iv) the saturation magnetization of the toner at a magnetic field of 796 kA / m is 20 to 35 Am ² / kg;
(V) The toner contains 60% by number or more of toner having a circularity of 0.93 or more,
(Vi) A magnetic toner wherein the dielectric loss tangent (tan δ) at 100 kHz of the toner satisfies the following formula (1).
(Equation 1)
_{(Tanδ H -tanδ L) / tanδ} L ≦ 0.20 (1)
[Wherein, tan δ _H represents the dielectric loss tangent at the glass transition temperature (° C.) + 10 ° C. of the toner,
tan [delta _L represents the dielectric loss tangent of the glass transition temperature of the toner (℃) -10 ℃. ]   2. The magnetic toner according to claim 1, wherein the toner contains 75% by number or more of toner having a circularity of 0.93 or more. The magnetic toner according to claim 1, wherein the toner has a dielectric loss tangent (tan δ) at 100 kHz and 40 ° C. of 2 × 10 ⁻³ to 1 × 10 ⁻² .   The magnetic toner according to claim 1, wherein the toner has a dielectric constant of 15 to 40 (pF / m) at 100 kHz and 40 ° C. 5.   5. The magnetic toner according to claim 1, wherein the magnetic substance has a number average particle diameter of 0.08 to 0.30 μm.   6. The magnetic toner according to claim 1, wherein the toner contains 30% by mass or more of a component having a molecular weight of 10,000 or less in the molecular weight distribution of the toner.   The magnetic toner according to claim 1, wherein the binder resin contains two or more resins having different softening points.   8. The toner according to claim 1, wherein an inorganic fine powder is externally added to the toner, and the inorganic fine powder contains at least two kinds of metal oxides having a number average particle diameter of 100 nm or less. The magnetic toner according to claim 1.   The metal oxide (I) whose dielectric constant is 5 pF / m or more larger than the dielectric constant of the toner and the metal oxide (II) whose dielectric constant is 5 pF / m or smaller than the dielectric constant of the toner are contained. The magnetic toner according to claim 8.

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