JP2011128277A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner, along with an image forming method, capable of stably obtaining images of high resolution and high definition over a long period of time regardless of environment. <P>SOLUTION: The toner is used in the image forming method including a development process of developing an electrostatic latent image formed on an electrostatic latent image carrier by the toner carried on a toner carrier and visualizing it. The toner carrier includes a substrate and a resin layer formed on the surface of the substrate. The resin layer contains resin containing a specified unit and conductive particles. The toner contains a binder resin, toner particles containing a colorant and inorganic fine powder, and the isoelectric point of the inorganic fine powder is ≥1.0 and ≤7.0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner used in electrophotography, electrostatic recording, and magnetic recording, and an image forming method.

  Conventionally, many methods are known as electrophotographic methods. Among these, as a developing system, a one-component developing system is preferably used because a developing machine with a simple structure has few troubles and maintenance is easy.

  In the one-component development system, toner is thinly applied onto a toner carrier by a layer thickness regulating member (hereinafter also referred to as “blade”), transported to a development area, and an electrostatic latent image is developed to develop a toner image. To do.

  In particular, among these one-component development systems, a magnetic one-component development system using a magnetic toner containing magnetic particles in the toner is preferably used in order to prevent toner scattering. . However, in this magnetic one-component system, since the toner receives a magnetic binding force on the toner carrier, a larger amount of charge is required for the toner in order to perform appropriate development. Further, due to an increase in stress accompanying an increase in the temporal binding force and the specific gravity of the toner, it becomes difficult to uniformly apply the toner to the toner carrier. It adheres and fuses to the surface and easily causes charging inhibition. In recent years, with the extension of the life of the copying machine main body and the expansion of the use environment, these phenomena are regarded as problems to be highly overcome.

  In these one-component development systems, for the purpose of uniform toner application and toner triboelectric charge control, a method for controlling the triboelectric charge amount distribution of the toner by providing a resin layer containing a charge control agent on the surface of the developing roller Is widely known. For example, Patent Documents 1 and 2 propose a developer carrier in which a resin layer contains a quaternary ammonium base-containing copolymer as a charge control agent. In this configuration, the negative counter ion of the quaternary ammonium base is ionized to become ionic conductivity, and the volume resistance of the resin layer can be reduced to some extent. Thereby, a local charge-up phenomenon can be suppressed. However, in such a method, the dispersion uniformity of the binder resin, the charge control agent and the conductive particles in the resin layer tends to be insufficient, and as a result, local frictional charging failure of the toner is likely to occur. When left in a high-temperature and high-humidity environment, the toner composition easily adheres to the developing roller, and is fused.

  Also in the toner field, various proposals have been made to include inorganic fine powder as an abrasive and a lubricant in the toner for the purpose of improving the durability of these toner carriers. For example, Patent Document 3 discloses that toner contains strontium titanate particles. However, such improvement by the toner alone is effective in preventing filming and fusing by the toner, which is generated on the electrostatic latent image bearing member, but it is a magnetic one component that generates magnetic binding force. In the development system, it has been difficult to suppress the fusion of the toner composition to the toner carrier.

Japanese Patent Registration No. 2955310 JP 2001-31136 A Japanese Patent No. 3385860

  That is, the object of the present invention is to prevent the toner carrying member from being contaminated by the toner composition in the developing process, and to form a uniform thin layer of toner on the developing roller. Another object of the present invention is to provide a toner capable of providing a high-quality image over a long period of time.

  The inventors of the present invention have a toner carrying body provided with a resin layer having a special composition on the surface, and a toner containing a special inorganic fine powder to maintain excellent developability even in a poor environment and to carry the toner. It has been found that the adhesion and adhesion of the toner composition to the body can be suppressed and a long life can be achieved to a high degree.

That is, the present invention is as follows.
(I) In a toner used in an image forming method having a development step of developing and visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a toner carried on the toner carrier,
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer includes at least a resin containing at least a unit represented by the following formulas (1) and (2), conductive Containing particles,
The toner comprises toner particles containing at least a binder resin and a colorant and an inorganic fine powder, and an isoelectric point of the inorganic fine powder is 1.0 or more and 7.0 or less.

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは、−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］
（ｉｉ）無機微粉体が、１００ｋＨｚ，４０℃における誘電率が５０ｐＦ／ｍ以上５００ｐＦ／ｍ以下であることを特徴とするトナー。
（ｉｉｉ）無機微粉体が、一次粒子の個数平均粒径が８０ｎｍ以上４００ｎｍ以下であることを特徴とするトナー。
（ｉｖ）静電潜像担持体に形成された静電潜像を、トナー担持体上に担持させたトナーにより現像して可視化する現像工程を有する画像形成方法において、
該トナー担持体は、少なくとも基体及び前記基体表面に形成された樹脂層を有しており、前記樹脂層は少なくとも下式（１）及び（２）に示されるユニットを少なくとも含有するアクリル樹脂、導電性粒子を含有し、
該トナーは、少なくとも結着樹脂と着色剤を含有するトナー粒子と無機微粉体を含有し、該無機微粉体の等電点が１．０以上７．０以下であることを特徴とする画像形成方法。

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and one of R ₅ , R _{6 and} R ₇ is an alkyl group having 4 to 18 carbon atoms. , The other group represents an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, A ⁻ is a halogen, hydrochloric acid, bromide, Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]
(Ii) A toner in which the inorganic fine powder has a dielectric constant of 50 pF / m or more and 500 pF / m or less at 100 kHz and 40 ° C.
(Iii) A toner wherein the inorganic fine powder has a number average particle size of primary particles of 80 nm or more and 400 nm or less.
(Iv) In an image forming method having a development step of developing and visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a toner carried on the toner carrier.
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer contains at least an acrylic resin containing at least units represented by the following formulas (1) and (2), conductive Containing functional particles,
The toner contains toner particles containing at least a binder resin and a colorant and an inorganic fine powder, and the isoelectric point of the inorganic fine powder is 1.0 or more and 7.0 or less. Method.

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは、−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］
（ｖ）トナー担持体が、前記樹脂層に熱硬化樹脂を含有することを特徴とする画像形成方法。
（ｖｉ）アクリル樹脂中に含有している前記ユニット（１）及び（２）のユニット組成比をそれぞれａ、ｂ、とした時、ｂ／（ａ＋ｂ）が０．５以上０．９以下であることを特徴とする画像形成方法。
（ｖｉｉ）アクリル樹脂が該熱硬化性樹脂１００質量部に対して１質量部以上４０質量部以下で添加されていることを特徴とする画像形成方法。

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and one of R ₅ , R _{6 and} R ₇ is an alkyl group having 4 to 18 carbon atoms. , The other group represents an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, A ⁻ is a halogen, hydrochloric acid, bromide, Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]
(V) The image forming method, wherein the toner carrier contains a thermosetting resin in the resin layer.
(Vi) When the unit composition ratios of the units (1) and (2) contained in the acrylic resin are a and b, respectively, b / (a + b) is 0.5 or more and 0.9 or less. An image forming method.
(Vii) The image forming method, wherein the acrylic resin is added in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the thermosetting resin.

  According to the present invention, there is no occurrence of adhesion and fusion of the toner composition to the toner carrier, and a high-resolution, high-definition image can be stably obtained over a long period of time regardless of the environment and the printed image. .

  One of the features of the present invention is that the toner carrier facing the electrostatic latent image carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer has at least the following formula (1): And a resin containing at least the unit shown in (2) and conductive particles.

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ_6、Ｒ₇のうち一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至１８のアルキル基を示し、Ｘは、−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and one of R ₅ , R _{6 and} R ₇ is an alkyl group having 4 to 18 carbon atoms. , The other group represents an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, A ⁻ is a halogen, hydrochloric acid, bromide, Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]

  By containing the unit having the above composition, the charge imparting ability to the toner can be improved. In particular, the charge imparting ability to the toner is improved by the presence effect of the long chain alkyl group in the cation unit represented by the formula (2). In addition, since the quaternary ammonium base has ionic conductivity, the conductivity of the resin layer is improved. Therefore, since it is possible to suppress excessive charging while quickly applying high charge to the toner, it is possible to reduce image defects such as blotch, ghost, and fog, and high quality with less image scattering with sufficient image density. An image can be obtained.

  Further, due to the presence of the long chain alkyl group in the resin containing the above unit, the compatibility with the thermosetting resin due to the presence effect of the long chain alkyl group in the ester unit represented by the formula (1). And the acrylic resin can exist uniformly in the resin layer. Furthermore, the dispersibility of the conductive particles present in the resin layer is also improved. As a result, a uniform triboelectric charge can be imparted to the toner, and the inorganic fine powder of the present invention can be uniformly dispersed and held on the surface of the toner carrier. It exists between the toner carrier and the toner and exhibits a lubrication and polishing effect, thereby preventing the toner composition from being fused to the toner carrier.

  Further, the presence of the long-chain alkyl group in the resin increases the hydrophobicity and lubricity, so that the moisture resistance is good and the environmental stability is excellent, and the inorganic fine powder of the present invention as a lubricant and abrasive is used. It is possible to suppress the fusion of the toner itself to the toner carrier. Therefore, it is possible to stably give an appropriate charge to the toner in any environment for a long period of time, and accordingly, it is possible to stably obtain a high-quality image with sufficient image density and less character scattering. It becomes.

  One of the characteristics of the present invention is that the toner contains an inorganic fine powder having an isoelectric point of 1.0 or more and 7.0 or less. Since the isoelectric point of the inorganic fine powder is within the above range, the inorganic fine powder is moderately dispersed and applied to the surface of the toner carrier during the transport and agitation processes in the developing device and is held on the surface of the toner carrier for a certain period of time. Therefore, fusion of the toner composition to the toner composition can be suppressed.

  If the isoelectric point of the inorganic fine powder is less than 1.0, the negative chargeability of the inorganic fine powder becomes too strong, and the adhesion of the inorganic fine powder itself to the toner carrier is likely to cause a filming phenomenon. On the other hand, when the isoelectric point of the inorganic fine powder exceeds 7.0, the inorganic fine powder is not sufficiently retained on the surface of the developing roller, and uneven use of the toner carrier occurs when used for a long period of time. As a result, image defects such as vertical stripes are likely to occur.

  In the present invention, the inorganic fine powder preferably has a dielectric constant of 50 pF / m or more and 500 pF / m or less at 2 kHz and 40 ° C.

  When the dielectric constant of the inorganic fine powder is less than 50 pF / m, when an AC electric field is used in the development process, the toner charge is likely to be relaxed, and in particular, the image density is likely to cause insufficient charge amount in a high temperature and high humidity environment. It tends to cause a decline. On the other hand, when the dielectric constant of the inorganic fine powder exceeds 500 pF / m, when an AC electric field is similarly used in the development process, overcharge is likely to occur, and thin layer formation defects on the toner carrier are likely to occur. , The image tends to cause bad effects such as ghost.

  In the present invention, the number average particle size of primary particles of the inorganic fine powder is preferably 80 nm or more and 400 nm or less.

  When the number average particle diameter is less than 80 nm, the hygroscopicity of the inorganic fine powder increases, and similarly, the charge amount is insufficient in a high temperature and high humidity environment, and the image density tends to decrease. On the other hand, when the number average particle diameter exceeds 400 nm, the polishing effect and the lubrication effect of the inorganic fine powder are reduced, and the toner composition tends to be fused to the toner carrier during long-term use.

  A preferable addition amount of these inorganic fine powders is 0.03 parts by mass or more and less than 7 parts by mass with respect to 100 parts by mass of the toner particles. When the added amount of the inorganic fine powder is less than 0.03 parts by mass, a sufficient toner carrier cleaning effect cannot often be exhibited. On the other hand, when the addition amount exceeds 7 parts by mass, the fluidity of the toner is deteriorated and the developing property and the like are liable to be adversely affected.

  As the binder resin for the toner particles contained in the toner of the present invention, a polyester resin, a vinyl copolymer resin, an epoxy resin, or a binder resin including a hybrid resin having a vinyl polymer unit and a polyester unit. Can be used.

  The toner particles contained in the toner of the present invention can be added as a release agent as necessary.

  Examples of release agents that can be used in the present invention include aliphatic hydrocarbon waxes and oxides thereof; block copolymers of the oxides; waxes based on fatty acid esters; Or what deoxidized all is mentioned. Among these release agents, one or more release agents may be contained in the toner particles as necessary.

  A preferable addition amount of the release agent is 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass per 100 parts by mass of the binder resin.

  In addition, these release agents can usually be contained in the toner particles by dissolving the resin in a solvent, increasing the temperature of the resin solution, adding and mixing with stirring, or mixing at the time of kneading.

  In the toner of the present invention, a charge control agent can be used as necessary in order to further stabilize the chargeability. Examples of the negative charge control agent for controlling the toner to be negative charge include an organometallic complex or a chelate compound. Examples of positive charge control agents that control the toner to be positively charged include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salt compounds, triphenylmethane dyes and their lake pigments, metal salts of higher fatty acids, etc. Is effective.

  A preferable content of the charge control agent is 0.5 to 10 parts by mass per 100 parts by mass of the binder resin. When the amount of the charge control agent is less than 0.5 parts by mass, sufficient charging characteristics may not be obtained, which is not preferable.

  When the amount exceeds 10 parts by mass, compatibility with other materials may be deteriorated, or charging may be excessive under low humidity, which is not preferable.

  The toner particles contained in the toner of the present invention are preferably made into a magnetic toner by adding a magnetic material as necessary. As the magnetic material, magnetic oxides such as magnetite, maghematite, ferrite and mixtures thereof are preferably used.

  Examples of the magnetic material include at least one element selected from the group consisting of magnesium, aluminum, silicon, phosphorus, titanium, zirconium, tin, calcium, manganese, cobalt, copper, nickel, strontium, and zinc. Magnetic iron oxide is included.

  The number average particle diameter of these magnetic materials is preferably 0.05 μm or more and less than 1.0 μm, more preferably 0.1 μm or more and less than 0.5 μm.

The BET specific surface area by nitrogen adsorption of the magnetic material is preferably 2 to 40 m ² / g, more preferably 4 to 20 m ² / g.

A preferable magnetic property of the magnetic material is that the saturation magnetization measured with a magnetic field of 795.8 kA / m is 10 to 200 Am ² / kg, and more preferably 70 to 100 Am ² / kg. A preferable residual magnetization is 1 to 100 Am ² / kg, and more preferably 2 to 20 Am ² / kg. Furthermore, the preferable coercive force is 1 to 30 kA / m, and more preferably 2 to 15 kA / m.

  A preferable content of the magnetic material is 20 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  To the toner particles contained in the toner of the present invention, a colorant can be added as necessary. Any appropriate pigment or dye can be used as the colorant.

  Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine yellow, alizarin yellow, bengara, phthalocyanine blue and the like. A preferable addition amount of the pigment is 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  Examples of the dye include azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, and the like. A preferable addition amount of the dye is 0.1 to 20 parts by mass, more preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  In the toner of the present invention, the binder resin and other additives are sufficiently mixed by a mixer such as a Henschel mixer and a ball mill and then melt-kneaded using a heat kneader such as a heating roll, a kneader, and an extruder. .

  Further, after cooling and solidification, pulverization and classification are performed, and further, the composite inorganic fine powder and, if necessary, desired additives are sufficiently mixed by a mixer such as a Henschel mixer.

  Examples of the mixer include a Henschel mixer (manufactured by Mitsui Mining); a super mixer (manufactured by Kawata); a ribocorn (manufactured by Okawara Seisakusho); a nauter mixer, a turbulizer, a cyclomix (manufactured by Hosokawa Micron); Pin mixer one (manufactured by Taiheiyo Kiko Co., Ltd.);

  Examples of the kneader include: KRC kneader (manufactured by Kurimoto Iron Works); bus co-kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel Works) PCM kneading machine (manufactured by Ikekai Tekkosho); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); kneedex (manufactured by Mitsui Mining Co., Ltd.); MS pressure kneader, Nider Ruder (Moriyama Seisakusho) Manufactured); Banbury mixer (manufactured by Kobe Steel).

  Examples of the pulverizer include counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron Co.); IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Industry Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.); ULMAX (manufactured by Nisso Engineering Co., Ltd.); SK Jet O Mill (manufactured by Seishin Enterprise Co., Ltd.); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.);

  Examples of the classifier include a class seal, a micron classifier, a speck classifier (manufactured by Seishin Enterprise Co., Ltd.); a turbo classifier (manufactured by Nissin Engineering Co., Ltd.); a micron separator, a turboplex (ATP), and a TSP separator (Hosokawa Micron). Elbow Jet (manufactured by Nippon Steel & Mining Co., Ltd.), dispersion separator (manufactured by Nippon Pneumatic Engineering Co., Ltd.); YM Microcut (manufactured by Yaskawa Shoji Co., Ltd.).

  Examples of sieving devices used for sieving coarse particles include Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokuju Kogakusha Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Shinto Kogyo Co., Ltd.); turbo screener (Turboe Co., Ltd.); micro shifter (Ogino Sangyo Co., Ltd.); circular vibrating screen, etc.

<Measurement method of isoelectric point of inorganic fine powder>
In the present invention, the isoelectric point of the inorganic fine powder is determined from the zeta potential as follows. The zeta potential of the present invention was measured using an ultrasonic zeta potential measuring device DT-1200 (manufactured by Dispersion Technology). Using pure water as a dispersion, prepare a 0.5 vol% aqueous solution of inorganic fine powder, disperse for 3 minutes with an ultrasonic disperser (VCX-750 manufactured by Sonic & Materials), and then stir while defoaming for about 10 minutes A dispersion was obtained. A graph of the pH change of the zeta potential of this dispersion is drawn using the above apparatus, and the isoelectric point is calculated from the graph. The isoelectric point is the pH value when the zeta potential becomes zero.

<Measurement method of dielectric constant of inorganic fine powder>
In the present invention, the dielectric constant of the inorganic fine powder 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. The dielectric constant of the inorganic fine powder is measured by measuring at a frequency of 2 kHz with the temperature fixed at 40 ° C. and applying a load of 1.47 N (150 g).

<Method for measuring particle size of inorganic fine powder>
About the number average particle diameter of the inorganic fine powder in the present invention, 100 average particle diameters were measured from photographs taken at a magnification of 50,000 times with an electron microscope, and the average was determined.

<Measurement method of melting point of wax>
The peak temperature of the maximum endothermic peak of the wax and toner is measured according to ASTM D3418-82 using a differential scanning calorimeter “Q1000” (manufactured by TA Instruments).

  The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, about 10 mg of toner is precisely weighed, put in an aluminum pan, and an empty aluminum pan is used as a reference. Measurement is performed at ° C / min. In the measurement, the temperature is once raised to 200 ° C., subsequently lowered to 30 ° C., and then the temperature is raised again. The maximum endothermic peak of the DSC curve in the temperature range of 30 ° C. to 200 ° C. in the second temperature raising process is defined as the maximum endothermic peak of the endothermic curve in the DSC measurement of the toner of the present invention.

<Measurement method of molecular weight distribution of resin>
The molecular weight distribution of the THF soluble part of the toner is measured by gel permeation chromatography (GPC) as follows.

First, the toner is dissolved in tetrahydrofuran (THF) at room temperature over 24 hours. The obtained solution is filtered through a solvent-resistant membrane filter “Maescho Disc” (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in THF is about 0.8% by mass. Using this sample solution, measurement is performed under the following conditions.
Apparatus: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)
Column: Seven series of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 ml

  In calculating the molecular weight of the sample, standard polystyrene resin (for example, trade name “TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F— 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", manufactured by Tosoh Corporation) are used.

  The toner carrier of the present invention will be described below.

  One feature of the present invention is that the toner carrier has at least a substrate and a resin layer formed on the surface of the substrate. The resin layer is made of at least a binder resin, a resin having a specific unit shown below, and conductive fine particles.

  The resin layer formed on the surface of the toner carrier of the present invention preferably contains a thermosetting resin as the binder resin. By using the thermosetting resin as a binder resin, the durability and environmental stability of the resin layer are improved. As the thermosetting resin, phenol resin, melamine resin, urea resin, and benzoguanamine resin are particularly preferable in terms of toughness and durability. Among these, a phenol resin is more preferable because it improves the abrasion resistance of the resin layer, is excellent in environmental stability, and is excellent in compatibility with an acrylic resin described later. Among these thermosetting resins, those that are soluble in alcohols, particularly lower alcohols such as methanol, ethanol, propyl alcohol, and butanol are preferable because of their good compatibility with the acrylic resin used in the present invention.

  The resin having an acrylic chain used in the present invention contains at least an ester unit represented by the following formula (1) and a cation unit represented by (2).

［式（１）中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は炭素数８乃至１８のアルキル基を示す。］

[In the formula (1), R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

［式（２）中、Ｒ₃は水素原子またはメチル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ｒ₅、Ｒ₆、Ｒ₇のうち少なくとも一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至３のアルキル基を示し、Ｘは、−ＣＯＯ−、−ＣＯＮＨ−、−Ｃ₆Ｈ₄−のいずれかであり、Ａ^-はハロゲン類、または塩酸、臭化水素酸、硫酸、リン酸、硝酸等の無機酸類におけるアニオン、またはカルボン酸、スルホン酸の如き有機酸類におけるアニオンのいずれかである。］

[In the formula (2), R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and at least one of R ₅ , R ₆ and R ₇ has 4 to 4 carbon atoms. 18 alkyl groups and other groups each represent an alkyl group having 1 to 3 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, and A ⁻ is a halogen, or Either an anion in an inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]

A more preferable form of the ester unit represented by the formula (1) is a long chain alkyl wherein R ₁ is a methyl group and R ₂ is selected from a decyl group, an undecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group. It is a group. When the alkyl group is a long chain as described above, the compatibility of the acrylic resin with the thermosetting resin of the present invention is increased. Therefore, the acrylic resin is uniformly present in the binder resin, and the toner can be uniformly charged. In addition, since the dispersibility of the pigment such as conductive particles in the resin is improved, the resistance distribution is uniform and local charge-up of the toner is suppressed.

When R ₂ is a lower alkyl group having fewer carbon atoms than the range specified in the present invention, the hydrophobicity is lowered, so that the polarity of the entire copolymer is increased. In this case, since the thermosetting resin that can be used in the present invention is weak in polarity, the compatibility of the resin having an acrylic chain with the binder resin is deteriorated, and the resin having an acrylic chain may be uniformly present in the resin layer. It becomes difficult. As a result, when the toner comes into contact with the resin layer, a difference in frictional charging occurs depending on the presence state of the resin having an acrylic chain, and the charge distribution tends to be non-uniform. At the same time, aggregation of the conductive agent is likely to occur, so that leak sites are locally present, and non-uniform charge distribution of the toner is increased.

On the other hand, when R ₂ is a long-chain alkyl group (19 or more carbon atoms) exceeding the octadecyl group, the hydrophobicity is increased, but the crystallinity is increased and the compatibility with the resin or solvent tends to be deteriorated. Resin and acrylic resin are easy to phase separate. Accordingly, in this case as well, the presence of the acrylic resin in the binder resin becomes non-uniform and the conductive agent tends to aggregate, so the toner charge distribution tends to be non-uniform.

  As the cation unit represented by the formula (2), those having the following structure are more preferable.

R ₃ is a methyl group,
R ₄ is a methylene group or ethylene group,
At least one selected from R ₅ , R ₆ and R ₇ is a long-chain alkyl group selected from octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, and tetradecyl;
The group that is not the long-chain alkyl group among R ₅ , R _6, and R _{7 is} an alkyl group having 1 to 3 carbon atoms.

As described above, the long-chain alkyl group is introduced into at least one selected from R ₅ , R ₆ and R ₇ , so that the cation unit as a charging site is uniformly present in the binder resin, and is added to the toner. On the other hand, it is possible to impart uniform charging. In particular, R ₅ is any one selected from the group consisting of octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, and R ₆ and R ₇ are each independently a methyl group. A cationic unit which is an ethyl group or a propyl group is preferred. This is because more uniform charging can be performed. Further, due to the presence of this long-chain alkyl group, the unit of formula (2) tends to exist on the surface of the resin layer. Since the unit of the formula (2) has a cationic property, as a result, the cationic unit increases on the surface of the resin layer, and the negative charge imparting ability to the toner is improved.

A ⁻ is an anion in halogens, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and other inorganic acids, and organic acids such as carboxylic acid and sulfonic acid. An anion containing a sulfur atom or a halogen atom is preferred, and a halogen such as Br ⁻ or Cl ⁻ is more preferred because of its good compatibility with the thermosetting resin.

  The acrylic resin that can be used in the present invention can be produced, for example, by copolymerization of an acrylic monomer and an acrylic monomer having a quaternary ammonium base.

  Examples of the acrylic monomer include monomers represented by the following formula (3).

［式中、Ｒ₁は水素原子またはメチル基を示し、Ｒ₂は水素原子、炭素数８乃至１８のアルキル基を示す。］

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a hydrogen atom or an alkyl group having 8 to 18 carbon atoms. ]

Examples of the monomer represented by the formula (3) include acrylates in which R ₁ is a hydrogen atom, methacrylates in which R ₁ is a methyl group, and R ₂ is a decyl group, an undecyl group, a dodecyl group, or a tridecyl group. A group, a tetradecyl group, or a methacrylate in which R ₁ is a methyl group is preferable.

  Examples of the monomer having a quaternary ammonium base include a monomer represented by the following formula (4).

［式中、Ｒ₃は水素原子、またはメチル基を示し、Ｒ₅、Ｒ₆、Ｒ₇の少なくともいずれか一つは炭素数４乃至１８のアルキル基、その他の基は炭素数１乃至３のアルキル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示し、Ａ^-はアニオンを示す。］

[Wherein, R ₃ represents a hydrogen atom or a methyl group, at least one of R ₅ , R ₆ , and R ₇ is an alkyl group having 4 to 18 carbon atoms, and the other groups are those having 1 to 3 carbon atoms] Represents an alkyl group, R ₄ represents an alkylene group having 1 to ₄ carbon atoms, and A ⁻ represents an anion. ]

As the monomer represented by the formula (4), it is preferable that at least one of R ₅ , R ₆ and R ₇ is an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, or a tetradecyl group. And R ₄ is preferably a methylene group or an ethylene group. In particular, R ₅ is any one of an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group, and R ₆ and R ₇ are selected from a methyl group, an ethyl group, and a propyl group. It is more preferable that it is an alkyl group. A ⁻ is an anion in halogens, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid and other inorganic acids, and carboxylic acid, sulfonic acid and other organic acids. An anion containing a sulfur atom or a halogen atom is preferable, and a halogen such as Br ⁻ or Cl ⁻ is more preferable.

  In the production process of the resin containing an acrylic chain that can be used in the present invention, a known polymerization method can be used. Examples of the method include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and the like, but a solution polymerization method is preferable because the reaction can be easily controlled. Solvents used in the solution polymerization method are lower alcohols such as methanol, ethanol, n-butanol, and isopropyl alcohol. In addition, other solvents such as xylene, toluene, ethyl acetate, isobutyl acetate, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide, dimethylformamide, and the like can be used as necessary. However, in order to improve the compatibility with the thermosetting binder resin used in the present invention, it is preferable to mainly use a lower alcohol as a solvent. The ratio of the solvent to the copolymerization monomer component is preferably 30 to 400 parts by mass with respect to 100 parts by mass of the solvent.

  The polymerization of the monomer mixture can be performed, for example, by heating the monomer mixture to 50 ° C. or higher and 100 ° C. or lower in the presence of a polymerization initiator in an inert gas atmosphere. The following are mentioned as an example of the polymerization initiator used in order to superpose | polymerize. t-butylperoxy-2-ethylhexanoate, cumyl perpivalate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl peroxide, t-butyl Cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) ), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate).

  The polymerization initiators can be used alone or in combination of two or more monomers. Usually, a polymerization initiator is added to the monomer solution to start the polymerization, but a part of the polymerization initiator may be added during the polymerization in order to reduce unreacted monomers. In addition, a method of promoting polymerization by irradiation with ultraviolet rays or an electron beam can be used, and these methods may be combined.

  The amount of the polymerization initiator used is preferably 0.05 parts by mass or more and 30 parts by mass or less, more preferably 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the copolymerization monomer component. The temperature of the polymerization reaction can be set according to the composition of the solvent to be used, the polymerization initiator, and the copolymerization monomer component, but is preferably 40 ° C or higher and 150 ° C or lower.

  As the monomer of the formula (4), a monomer obtained by quaternizing the monomer represented by the following formula (5) with a quaternizing agent can be used.

［式（５）中、Ｒ₃は水素原子、またはメチル基を示し、Ｒ₅、Ｒ₆はアルキル基を示し、Ｒ₄は炭素数１乃至４のアルキレン基を示す。］

[In Formula (5), R ₃ represents a hydrogen atom or a methyl group, R ₅ and R ₆ represent an alkyl group, and R ₄ represents an alkylene group having 1 to 4 carbon atoms. ]

  Examples of compounds that can be used as the quaternizing agent include alkyl halides and organic acid compounds.

  Examples of alkyl halides are shown below. Butyl bromide, 2 ethylhexyl bromide, octyl bromide, lauryl bromide, stearyl bromide, butyl chloride, 2 ethylhexyl chloride, octyl chloride, lauryl chloride, stearyl chloride and the like. Examples of organic acid compounds are shown below. methyl p-toluenesulfonate, dimethyl sulfate, methyl hydroxynaphthalenesulfonate, and the like.

  The amount of the quaternizing agent used is preferably 0.8 mol or more and 1.0 mol or less with respect to 1 mol of the monomer represented by the formula (5). Quaternization of such a monomer can be performed, for example, by heating the monomer and the quaternizing agent to 60 ° C. or higher and 90 ° C. or lower in a solvent.

  Further, after copolymerizing the monomer of the above formula (3) and the monomer of the formula (5), further quaternizing with the above quaternizing agent, the desired quaternary ammonium base-containing acrylic copolymer is obtained. It is also possible to obtain. In addition, for example, the monomer represented by the formula (5) is quaternized with an alkyl halide such as methyl chloride and then copolymerized with the monomer represented by the formula (3). The obtained quaternary ammonium base-containing acrylic copolymer is treated with an acid such as p-toluenesulfonic acid and hydroxynaphthalenesulfonic acid to perform counterion exchange, and contains a quaternary ammonium base as a target anion species. An acrylic copolymer can also be used.

  The composition ratio of each unit in the acrylic resin is such that b / (a + b) is 0.5 when the unit composition ratio of the unit (1) in the acrylic resin is a and the unit composition ratio of the unit (2) is b. It is preferable that it is 0.9 or more.

  By setting b / (a + b) to 0.5 or more, the negative charge imparting characteristics of the acrylic resin are improved, and the effect of ionic conductivity due to the quaternary ammonium salt structure is easily enhanced, so that the toner can be charged quickly. Improves. By setting b / (a + b) to 0.9 or less, it is possible to uniformly exist in the binder resin. The compatibility with the binder resin becomes good, and the acrylic resin tends to exist uniformly in the resin layer. Furthermore, the dispersibility of the conductive particles present in the resin layer is also improved.

  In addition, in this invention, when the unit which satisfy | fills the structure of said (1), (2) each unit contains multiple types in an acrylic resin, the sum total of the multiple types of unit composition ratio which satisfy | fills the structure of (1) is set. The total of a plurality of types of unit composition ratios satisfying the structure of a and (2) is defined as b.

  The acrylic resin used in the present invention may contain other units in addition to the units (1) and (2). The content of other units contained in the acrylic resin is preferably 30 mol% or less of the total number [mol] of units constituting the acrylic resin. By making the content rate of other units 30 mol% or less, it is easy to obtain the effect by introducing the units (1) and (2).

  The addition amount of the resin containing at least the units shown in (1) and (2) used in the present invention is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the thermosetting resin as the binder resin. It is preferable that By setting it in this range, the charge control effect by addition can be exhibited, and the film can be uniformly present in the binder resin, so that the coating strength can be maintained.

In the present invention, in order to adjust the resistance value of the resin layer, the following conductive particles are included in the coating layer. For example, fine powders of metals such as aluminum, copper, nickel and silver;
Conductive metal oxides such as antimony oxide, indium oxide, tin oxide, titanium oxide, zinc oxide, molybdenum oxide, potassium titanate;
Conductive carbon black such as crystalline graphite, various carbon fibers, furnace black, lamp black, thermal black, acetylene black, channel black;
Furthermore, it is a metal fiber.

  Among these, carbon black and graphite are particularly preferable because of excellent dispersibility and excellent electrical conductivity. Among these, conductive amorphous carbon is particularly excellent in electrical conductivity, and can be given a certain degree of conductivity by simply filling a polymer material to impart conductivity and controlling the amount added. Therefore, it is preferably used. In addition, the dispersion stability and coating stability are also improved due to the thixotropic effect of the paint.

  You may use the said electroconductive particle in mixture of 2 or more types. Moreover, the blending amount of the conductive particles is preferably 20 parts by mass or more and 100 parts by mass or less with respect to the binder resin. By setting this range, the resistance value can be set to a desired level without impairing the strength of the resin layer.

In the present invention, the volume resistance of the resin layer on the surface of the developer carrying member is preferably 10 ⁻¹ Ω · cm or more and 10 ² Ω · cm or less. By setting the value within this range, fixing of the developer onto the developer carrying member due to charge-up, and frictional charging failure from the surface of the developer carrying member to the developer caused by the charge-up of the developer can be prevented. Can be prevented. In particular, if the volume resistance value of the resin layer on the surface of the developer carrying member exceeds 10 ² Ω · cm, poorly imparted triboelectric charge to the developer is likely to occur. As a result, blotches (spot images and wave pattern images) and image density Decrease is likely to occur.

  In the present invention, in order to make the surface roughness uniform and maintain an appropriate surface roughness in the conductive resin coating layer, a more preferable result can be obtained by adding rough particles for forming irregularities. can get.

  Spherical particles are preferable as the rough particles for forming the irregularities used in the present invention. By using spherical particles, a desired surface roughness can be obtained with a smaller addition amount than that of amorphous particles, and an uneven surface having a uniform surface shape can be obtained. Furthermore, even when the surface of the coating layer is worn, the change in the surface roughness of the coating layer is small, and the change in the thickness of the toner layer on the developer carrying member hardly occurs. From this, the effect of making the toner charge uniform, sleeve ghosting good, streaking and unevenness hardly occurring, and preventing the occurrence of sleeve contamination and fusion by the toner on the developer carrying member can be achieved for a long time. It can be demonstrated over a long time.

  As the base of the developer carrying member used in the present invention, there are members such as a cylindrical member, a columnar member, and a belt-like member. In the developing method without contact with the drum, a rigid cylindrical tube such as a metal is used. Alternatively, a solid bar is preferably used. As such a substrate, a non-magnetic metal or alloy such as aluminum, stainless steel, brass or the like is formed into a cylindrical shape or a cylindrical shape and subjected to treatment such as polishing or grinding is preferably used. These substrates are used after being molded or processed with high accuracy in order to improve the uniformity of the image. For example, the straightness in the longitudinal direction is preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less. Further, the fluctuation of the gap between the sleeve and the photosensitive drum, for example, the fluctuation of the gap between the sleeve and the vertical surface when the sleeve is rotated by a uniform spacer is preferably 30 μm or less. It is 20 μm or less, more preferably 10 μm or less. Aluminum is preferably used because of material cost and ease of processing.

  The method for forming the conductive resin coating layer can be formed, for example, by dispersing and mixing the components for the conductive resin coating layer in a solvent to form a paint, coating the substrate, and drying, solidifying, or curing. . For dispersing and mixing each component into the coating liquid, a known dispersing apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill can be suitably used. As a coating method, a known method such as a dipping method, a spray method, or a roll coating method can be applied.

  In the present invention, the arithmetic average roughness Ra (JIS B0601-2001) is preferably 0.3 μm or more and 2.5 μm or less, and preferably 0.4 μm or more and 2.0 μm or less as the roughness of the surface of the conductive resin coating layer. More preferably. When Ra on the surface of the conductive resin coating layer is less than 0.4 μm, there is almost no unevenness on the surface of the conductive resin coating layer, so that the amount of developer on the developer carrier becomes unstable and the conductive resin The wear resistance and developer stain resistance of the coating layer may be insufficient. On the other hand, when Ra exceeds 2.0 μm, the transport amount of the developer on the developer carrying member becomes too large, and it becomes difficult to uniformly charge the developer, and the mechanical strength of the conductive resin coating layer is also increased. May fall.

  The thickness of the conductive resin coating layer configured as described above is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 4 μm or more and 20 μm or less, in order to obtain a uniform film thickness, The thickness is not particularly limited to this.

<Method for measuring arithmetic mean roughness (Ra) of developer carrier surface>
The measurement of the arithmetic mean roughness (Ra) on the surface of the developer carrying member is based on the surface roughness of JIS B0601 (2001), using a surf coder SE-3500 manufactured by Kosaka Laboratories. The evaluation length was 8 mm and the feed rate was 0.5 mm / s. The measurement positions are a total of three positions, the middle position between the developer carrier and the both ends of the coating. Further, after rotating the 90 ° developer carrier, the same three locations, and further 90 ° developer carrier. After the rotation, the measurement was similarly performed at three points, a total of nine points, and the average value was taken.

<Method for Measuring Volume Resistance of Conductive Resin Coating Layer of Developer Carrier>
A 7 μm to 20 μm coating layer was formed on a 100 μm thick polyethylene terephthalate (PET) sheet, and volume resistivity was measured with a resistivity meter Loresta AP (manufactured by Mitsubishi Chemical Corporation) using a 4-terminal probe. The measurement environment is a temperature of 20 to 25 ° C. and a humidity of 50 to 60% RH.

<Volume average particle diameter of particles added to developer carrier>
A laser diffraction type particle size distribution analyzer “Coulter LS-230 type particle size distribution meter” (trade name, manufactured by Beckman Coulter, Inc.) was used. A small amount module was used for the measurement, and isopropyl alcohol (IPA) was used as the measurement solvent. First, the measurement system of the measuring apparatus was washed with IPA for about 5 minutes, and a background function was executed after washing. Next, about 10 mg of a measurement sample is added to 50 ml of IPA. Disperse the sample suspension for about 2 minutes with an ultrasonic disperser to obtain a sample solution, and then gradually add the sample solution into the measurement system of the measurement device. The PIDS on the screen of the device is 45%. The sample concentration in the measurement system was adjusted to be 55% to 55%. Thereafter, measurement was performed, and a volume average particle diameter calculated from the volume distribution was obtained.

<Measurement of volume resistance of conductive fine particles>
Particles are placed in an aluminum ring with a diameter of 40 mm and pressure-molded at 2500 N. In the low resistance region, a 4-terminal probe is used with a resistivity meter Loresta AP (Mitsubishi Chemical), and in the middle and high resistance regions, Hiresta IP (Mitsubishi Chemical) ) To measure the volume resistance value using a ring electrode probe. The measurement environment is 20 to 25 ° C. and 50 to 60% RH.

<Resin analysis method>
The structure of the acrylic resin polymer was determined by analyzing a sample obtained by scraping the resin layer of the developer carrier with a pyrolysis GC / MS apparatus “Voyager” (trade name, manufactured by Thermo Electron). Thermal decomposition temperature: 600 ° C., column: HP-1 (15 m × 0.25 mm × 0.25 μm), Inlet: 300 ° C., Split: 20.0, injection amount: 1.2 ml / min, temperature rise: 50 It performed on the conditions of (degreeC (4min) -300 degreeC (20 degreeC / min)).

  The present invention will be described more specifically with reference to the following examples.

[Production example of inorganic fine powder]
(Inorganic fine powder production example 1)
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 (μS / cm). 0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Further, distilled water was added so as to be 0.5 mol / L in terms of SrTiO ₃ . The slurry was heated to 83 ° C. at 6.0 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, cool to room temperature, remove the supernatant, and repeat washing with pure water.

  Furthermore, in a nitrogen atmosphere, the slurry was placed in an aqueous solution in which 7.0% by mass of sodium stearate was dissolved with respect to the solid content of the slurry, and surface treatment was performed while stirring. The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with stearic acid.

  The obtained strontium titanate had a hexahedral shape in which the particle shape was approximately cubic or cuboid. This hydrophobized inorganic fine powder 1 having a number average particle diameter of 100 nm and hexahedral strontium titanate particles was obtained. The physical properties of the resulting inorganic fine powder 1 are shown in Tables 4 to 5.

(Inorganic fine powder production example 2)
The hydrous titanium oxide obtained by hydrolysis by adding aqueous ammonia to the aqueous titanium tetrachloride was washed with pure water, and 0.25% sulfuric acid was added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.7, and washing was repeated until the electrical conductivity of the supernatant reached 50 μS / cm.

A 0.95-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Further, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ .

  The slurry was heated to 65 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 8 hours after reaching 65 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.

  Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 2% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous magnesium sulfate solution is dropped, and magnesium stearate is deposited on the perovskite crystal surface. Was precipitated.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate fine particles whose surface was treated with magnesium stearate. The obtained strontium titanate had a hexahedral shape in which the particle shape was approximately cubic or cuboid. This hydrophobized inorganic fine powder 2 which is hexagonal strontium titanate particles having a number average particle diameter of 80 nm was obtained. Tables 4 to 5 show the physical properties of the obtained inorganic fine powder 2.

(Inorganic fine powder production example 3)
Dissolve titanyl sulfate powder in distilled water and adjust the solution to which sulfuric acid and distilled water are added so that the Ti concentration in the solution is 1.5 mol / l and the acid concentration at the end of the reaction is 2.0 mol / l. The solution was heated at 110 ° C. for 36 hours in a sealed container to cause a hydrolysis reaction, and then washed with water to sufficiently remove sulfuric acid and impurities to obtain a metatitanic acid slurry. To this slurry, strontium carbonate (average particle diameter of 80 nm) was added so as to have an equimolar amount with respect to titanium oxide, thoroughly mixed in an aqueous wet, washed, dried, and then washed at 1100 ° C. The inorganic fine powder 1 having a number average particle diameter of 250 nm was obtained through time sintering, machine pulverization, and classification. The physical properties of the resulting inorganic fine powder 1 are shown in Tables 4 to 5.

(Inorganic fine powder production examples 4 and 5)
Using the above metatitanic acid slurry, the sintering conditions were changed to 1200 ° C./5 hours or 1300 ° C./6 hours, the pulverization and classification conditions were adjusted as appropriate, and the inorganic fine powder production example 1 was performed in the same manner as described above. Inorganic fine powder 4 having a particle diameter of 400 nm and inorganic fine powder 5 having a number average particle diameter of 1100 nm were obtained. The physical properties of the resulting inorganic fine powder are shown in Tables 4 to 5.

(Inorganic fine powder production example 6)
Ilmenite ore containing 50% by mass of TiO ₂ equivalent was used as a starting material. The raw material was dried at 150 ° C. for 2 hours, and sulfuric acid was added and dissolved to obtain an aqueous TiOSO ₄ solution. This was concentrated, and after adding 4.5 parts by mass of a titania sol having rutile crystals as a seed, hydrolysis was performed at 125 ° C. to obtain a slurry of TiO (OH) ₂ containing impurities. This slurry was repeatedly washed with water at pH 5 to 6 to sufficiently remove sulfuric acid, FeSO ₄ , and impurities. Then, a slurry of high purity metatitanic acid [TiO (OH) ₂ ] was obtained. This slurry was filtered, baked at 180 ° C. for 2 hours, and then pulverized repeatedly by a jet mill until no aggregates of fine particles disappeared, and titanium oxide having an average particle diameter of 32 nm was obtained. This titanium oxide is dispersed in ethanol, and 7 parts by mass of i-butyltrimethoxysilane as a hydrophobizing agent and 7 parts by mass of trifluoropropyltrimethoxysilane as a hydrophobizing agent with respect to 100 parts by mass of titanium oxide. The mixture was dropped and mixed with sufficient stirring so that coalescence of mass parts and particles did not occur, and reacted. Further, the pH of the slurry was adjusted to 6.5 with sufficient stirring.

  This was filtered and dried, then heat-treated at 170 ° C. for 2 hours, and then repeatedly subjected to crushing treatment by a jet mill until titanium oxide aggregates disappeared, which is an inorganic titanium oxide particle having a number average particle diameter of 60 nm. A fine powder 6 was obtained. Tables 4 to 5 show the physical properties of the obtained inorganic fine powder 6.

(Inorganic fine powder production example 7)
A hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution is neutralized to pH 7 with aqueous ammonia, filtered and washed with water. The cake obtained by flocculating titanium oxide with hydrochloric acid is used to prepare anatase titania sol. Obtained. The average primary particle size of this sol was 7 nm.

In addition, an ilmenite ore containing 50% by mass of TiO ₂ equivalent as a starting material was used, and after the raw material was dried at 150 ° C. for 2 hours, sulfuric acid was added to dissolve the TiOSO ₄ aqueous solution. Obtained. This was concentrated, and 4.0 parts by mass of the anatase titania sol was added as a seed, followed by hydrolysis at 120 ° C. to obtain a slurry of TiO (OH) ₂ containing impurities. This slurry was repeatedly washed with water at pH 5 to 6 to sufficiently remove sulfuric acid, FeSO ₄ , and impurities. Then, a slurry of high purity metatitanic acid [TiO (OH) ₂ ] was obtained.

The metatitanic acid was heat-treated at 300 ° C. for 5 hours, and then sufficiently crushed, and a hydrophilic anatase crystal hydrophilic titanium oxide fine powder having a BET specific surface area of 120 m ² / g and a number average particle size of 25 nm was obtained. Obtained.

Next, 20 parts by mass of i-C ₄ H ₉ —Si— (OCH ₃ ) ₃ as a hydrophobizing agent is sufficiently dispersed in 100 parts by mass of the hydrophilic titanium oxide in water. While being added dropwise, the mixture was hydrophobized. Then, after filtering and drying at 120 ° C. for 5 hours, heat treatment is performed at 170 ° C. for 5 hours, and pulverization is performed by a jet mill until there are no aggregates of hydrophobic titanium oxide fine particles, and oxidation with a number average particle diameter of 50 nm is performed. Inorganic fine powder 7 which is titanium particles was obtained. Tables 4 to 5 show physical property values of the obtained inorganic fine powder 7.

(Inorganic fine powder production example 8)
In the production example 3 of the inorganic fine powder, titanic acid having a number average particle size of 1500 nm was changed in the same manner except that strontium carbonate was changed to barium carbonate particles having a number average particle size of 100 nm and the firing conditions were changed to 1300 ° C./6 hours. Inorganic fine powder 8 which is barium particles was obtained. Tables 4 to 5 show physical property values of the obtained inorganic fine powder 8.

(Inorganic fine powder production example 9)
Oxygen was supplied to the combustor at 80 Nm ³ / Hr and argon gas was supplied at 2 Nm ³ / Hr to form a flame for igniting aluminum powder. Next, aluminum powder (average particle size: about 60 μm, supply amount: 30 kg / Hr) was supplied from the aluminum powder supply device to the reactor along with nitrogen gas (supply amount: 5 Nm ³ / Hr) through the combustor. In the reaction furnace, the aluminum powder was burned by a flame and oxidized to obtain inorganic fine powder 9 which was alumina particles having a number average particle diameter of 1100 nm. Tables 4 to 5 show physical property values of the obtained inorganic fine powder 9.

[Production example of toner carrier]
<Acrylic group-containing resin solution for toner carrier (A-1)>
In a four-necked separable flask equipped with a stirrer, a cooler, a thermometer, a nitrogen inlet tube and a dropping funnel, 46.1 parts by mass of dipropylaminoethyl methacrylate (formula (10)), lauryl bromide formula (formula (11 )) (Quaternizing agent) 53.9 parts by mass and 50 parts by mass of ethanol were mixed and stirred until the system was uniform. While continuing to stir, the temperature was raised to 70 ° C., and the mixture was stirred for 5 hours to quaternize the monomer. (2-Methacryloyloxyethyl) lauryldipropylammonium bromide (formula ( 12)) was obtained. After cooling the obtained reaction solution, 17.4 parts by mass of tridecyl methacrylate as a copolymer component, 50 parts by mass of ethanol as a solvent, and 1.0 part by mass of azobisisobutyronitrile (AIBN) as a polymerization initiator And stirred until the system was uniform. While continuing the stirring, the temperature in the reaction system was raised to 70 ° C., and the portion charged in the dropping funnel was added over 1 hour. After completion of dropping, the reaction was further continued for 5 hours under reflux with introduction of nitrogen, and further 0.2 parts by mass of AIBN was added, followed by reaction for 1 hour. Further, this solution was diluted with ethanol to obtain an acrylic group-containing resin solution 1 having a solid content of 40%. Table 1 shows the blending ratio of the acrylic group-containing resin solution (A-1), and Table 2 shows the structure.

<Production example of acrylic group-containing resin solutions (A-2) to (A-20)>
Acrylic group-containing resin solutions (A-2) to (A) are produced in the same manner as in the production example of the acrylic group-containing resin solution (A-1) except that the copolymerization components to be used are those shown in Table 1. -20) was obtained. The structure of the acrylic group-containing resin solution is shown in Table 2.

<Production Example of Conductive Particle (B-1) for Toner Carrier>
Mesocarbon microbeads obtained by heat treatment of heavy coal oil were washed and dried, then mechanically dispersed with an atomizer mill, and carbonized by primary heat treatment at 800 ° C. in a nitrogen atmosphere. . Subsequently, secondary dispersion was performed with an atomizer mill, followed by heat treatment at 2900 ° C. in a nitrogen atmosphere, and further classification to obtain graphite particles (B-1) having a volume average particle size of 6.6 μm.

<Production Example of Toner Carrier (C-1)>
Methanol was added to the following materials to adjust the solid content to 40%, and this was dispersed for 2 hours in a sand mill (using glass beads having a diameter of 1 mm as media particles).
-Binder resin 167 parts by mass (solid content 100 parts by mass)
(Resol type phenol resin solution using ammonia catalyst (trade name: J-325, manufactured by DIC Corporation))
Conductive particles (B-1) 30 parts by mass Conductive particles (B-2) 50 parts by mass (carbon black # 5500 (trade name, manufactured by Tokai Carbon))
・ Acrylic group-containing resin (A-1) 25 parts by mass (solid content 10 parts by mass)
・ Roughness imparting particles 60 parts
(Nikabeads ICB-0520 (Nippon Carbon Co., Ltd .; trade name), average particle size 5.9 μm)

  After separating the glass beads using a sieve, methanol was added so that the solid concentration was 33% to obtain a paint.

  As the base, a cylindrical aluminum tube having an outer diameter of 32.0 mmφ and 24.5 mmφ with an upper and lower end masked and an arithmetic average roughness Ra of 0.2 μm was prepared. The substrate was erected vertically and rotated at a constant speed, and the paint was applied while lowering the spray gun at a constant speed. Subsequently, the coating layer was dried and cured by heating at 150 ° C. for 30 minutes in a hot air drying oven to form a resin layer on the substrate to prepare a toner carrier (C-1). The layer thickness of the resin layer of the toner carrier (C-1) was 15 μm. Tables 1 to 3 show the configuration and physical properties of the resin layer of the toner carrier (C-1).

<Production Examples of Toner Carriers (C-2) to (C-24)>
Toner carriers (C-2) to (C-24) were prepared in the same manner as in the production example of toner carrier (C-1) except that the composition of the paint was as shown in Table 3. Tables 1 to 3 show the constitution and physical properties of the resin layer of the obtained toner carrier.

[Example 1]
(Toner Production Example 1)
Styrene-n-butylacrylic copolymer (copolymerization mass ratio = 78: 22, weight average molecular weight = 380,000) 100 parts by mass Low molecular weight ethylene-propylene copolymer (melting point 102 ° C.) 6 parts by mass Charge control Agent (Azo-based iron complex compound) 2 parts by mass, magnetic iron oxide 90 parts by mass (average particle size 0.25 μm, coercive force 11.2 KA / m, residual magnetization 8.8 Am ² / kg, saturation magnetization 80.3 Am ² / kg)
The above mixture was melt-kneaded with a twin-screw kneader heated to 130 ° C., and the cooled mixture was coarsely pulverized with a hammer mill. Further, the mixture is finely pulverized by a collision type pulverizer, and the obtained finely pulverized product is classified by an air classifier to obtain toner particles in which particles having a weight average diameter of 7.6 μm, 10.1 μm or more are 6.8% by volume. It was.

To 100 parts by mass of the toner particles, 1.0 part by mass of hydrophobic dry silica (BET specific surface area: 300 m ² / g) and 1.0 part by mass of inorganic fine powder 1 were added, and a Henschel mixer FM500 (Mitsui Miike Co., Ltd.) was added. The toner (1) of the present invention was obtained by rotating and stirring for 4 minutes at a stirring blade rotational speed of 1100 rpm to disperse and adhere to the toner surface.

<Image evaluation test>
The toner carrier of a commercially available copying machine imageRUNNER iR3245 (manufactured by Canon Inc.) is replaced with the toner carrier C-1 of the present invention, and the toner (1) is used to produce a high temperature and high humidity environment (1) (30 ° C. / 80% RH) and high-temperature and high-humidity environment (2) (35 ° C./90% RH), using a test chart with a printing ratio of 20%, in the intermittent mode of 5 sheets / 30 sec, 100,000 0000 A sheet copy was made, and the image density, fogging, fusion to the toner carrier, and wear of the toner carrier were evaluated as shown below. The results are shown in Table 4.

  The following evaluation was performed using the toner.

1) Image Density With a “Macbeth reflection densitometer” (manufactured by Macbeth Co., Ltd.), an SPI filter was used to measure the reflection density of an image having a 5 mm diameter circle, and the average value was evaluated.
Rank 5: Reflection density 1.45 or more Rank 4: Reflection density 1.40 or more and 1.44 or less Rank 3: Reflection density 1.35 or more and 1.39 or less Rank 2: Reflection density 1.30 or more and 1.34 or less Rank 1 : Reflection density less than 1.29

2) Fog Using a reflection densitometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku), the reflection density (Dr) of the transfer paper before image formation and the reflection density after copying the solid white image The worst value was measured as (Ds), and the difference (Ds−Dr) was evaluated as the fog value.
Rank 5: Fog less than 0.1 Rank 4: Fog 0.1 to less than 0.5 Rank 3: Fog 0.5 to less than 1.5 Rank 2: Fog 1.5 to less than 2.0 Rank 1: Fog 2. 0 or more

3) Evaluation of anti-fusing property of toner composition to toner carrier After completion of the 100,000 0000 copy test, output an A3 halftone image (30H) and a solid black image, and visually observe the image and the toner carrier. The degree of fusion of the toner composition to the toner carrier was evaluated.
Rank 4: There is no fusion of the toner composition on the toner carrier. Rank 3: Partial fusion of the toner composition is seen on the toner carrier, but there is no influence on the image. Rank 2: Toner Although the toner composition is partially fused on the carrier, it can be partially confirmed on the HT image but not on the solid image. Rank 1: The toner composition is fused on the toner carrier. , Can be confirmed with a solid image

4) Abrasion resistance evaluation of toner carrier The change rate of the arithmetic average roughness Ra of the toner carrier before and after the 100,000 000 copy test was obtained and evaluated by the following formula.
Rank 4: Ra change rate is less than 3.0% Rank 3: Ra change rate is 3.0% or more and less than 5.0% Rank 2: Ra change rate is 5.0% or more and less than 7.0% rank 1: Ra change rate is 7.0% or more

[Examples 2 to 22 and Comparative Examples 1 to 12]
In Example 1, as shown in Tables 4 and 5, the evaluation was performed in the same manner as in Example 1 except that the inorganic fine powder added to the toner and the toner carrier were changed. The evaluation results are shown in Tables 4 to 5.

  Regarding Examples 2 to 3, as in Example 1, all evaluations were good.

  Regarding Example 4, since the number average particle diameter of the inorganic fine powder is the upper limit of the range of claim 3, the rank of the evaluation of the adhesion resistance under the high temperature and high humidity environment (2) is 3.

  Regarding Example 6, since the dielectric constant of the inorganic fine powder is the lower limit of the range of claim 2, the concentration under high-temperature and high-humidity environment (1), (2) and the fog evaluation rank are 4.

  Regarding Examples 5, 8, and 7, since the number average particle diameter of the inorganic fine powder exceeds the upper limit within the range of claim 3, the rank of the anti-fusing evaluation under the high temperature and high humidity environment (2) is 2. It is.

  Regarding Examples 8 and 7, since the isoelectric point of the inorganic fine powder is the upper limit of the range of claim 1, the rank of the evaluation of the image density in the high temperature and high humidity environment (2) is 2.

  Regarding Examples 10 to 16, since the structures of the units (1) and (2) of the toner carrier are the upper and lower limits of Claim 1, the evaluation of anti-fusing property under a high temperature and high humidity environment (2) The rank is 3.

  Regarding Examples 15 to 16, since the unit (2) unit of the toner carrier or the acrylic group is not contained, the rank of the anti-fusing property evaluation in the high temperature and high humidity environment (1) is 2.

  Regarding Examples 17 and 18, the composition ratio b / (a + b) of the units (1) and (2) of the toner carrier is outside the range of claim 4, so in the high temperature and high humidity environment (2). The evaluation rank of fog, abrasion resistance, and fusion resistance is 2.

  Regarding Examples 19 and 20, since the abundance of units (1) and (2) in the toner carrier is the upper and lower limits of claim 5, the rank of evaluation of the wear resistance of the toner carrier is as follows. Is 2 to 3.

  Regarding Examples 18 and 19, since the amount of the formula (1) and formula (2) units in the toner carrier is outside the range of claim 5, fog and abrasion resistance in the high temperature and high humidity environment (2) The rank of the abrasion resistance and anti-fusing property evaluation is 2.

  With respect to Comparative Examples 1 and 2, the isoelectric point of the inorganic fine powder and the structure of the formula (1) and formula (2) units in the toner carrier are outside the scope of claim 1, so that the environment of high temperature and high humidity The rank of evaluation of the brazing resistant in (1) and the high temperature and high humidity environment (2) is 1.

  Regarding Comparative Examples 3 to 10, since the structure of the units (1) and (2) of the toner carrier is outside the scope of claim 1, the high temperature and high humidity environment (1) and the high temperature and high humidity environment (2) The rank of the anti-fusing evaluation is 2 and 1.

  Regarding Comparative Example 11, since the toner carrier has only the formula (1) unit, and Comparative Example 12 has only the formula (2) unit, the evaluation of wear resistance and fusing resistance in each environment is performed. Has a rank of 1.

Claims (7)

In a toner used in an image forming method having a development step of developing and visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a toner carried on the toner carrier,
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer includes at least a resin containing at least a unit represented by the following formulas (1) and (2), conductive Containing particles,
The toner contains toner particles containing at least a binder resin and a colorant and an inorganic fine powder, and the isoelectric point of the inorganic fine powder is 1.0 or more and 7.0 or less.

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and one of R ₅ , R _{6 and} R ₇ is an alkyl group having 4 to 18 carbon atoms. , The other group represents an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, A ⁻ is a halogen, hydrochloric acid, bromide, Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]   The toner according to claim 1, wherein the inorganic fine powder has a dielectric constant of 50 pF / m or more and 500 pF / m or less at 2 kHz and 40 ° C.   The toner according to claim 1, wherein the inorganic fine powder has a number average particle size of primary particles of 80 nm or more and 400 nm or less. In an image forming method comprising a developing step of developing and visualizing an electrostatic latent image formed on an electrostatic latent image carrier with a toner carried on the toner carrier,
The toner carrier has at least a substrate and a resin layer formed on the surface of the substrate, and the resin layer includes at least a resin containing at least a unit represented by the following formulas (1) and (2), conductive Containing particles,
The toner contains toner particles containing at least a binder resin and a colorant and an inorganic fine powder, and the isoelectric point of the inorganic fine powder is 1.0 or more and 7.0 or less. Method.

[Wherein, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 8 to 18 carbon atoms. ]

[Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkylene group having 1 to 4 carbon atoms, and one of R ₅ , R _{6 and} R ₇ is an alkyl group having 4 to 18 carbon atoms. , The other group represents an alkyl group having 1 to 18 carbon atoms, X is any one of —COO—, —CONH—, and —C ₆ H ₄ —, A ⁻ is a halogen, hydrochloric acid, bromide, Either an anion in an inorganic acid such as hydrogen acid, sulfuric acid, phosphoric acid or nitric acid, or an anion in an organic acid such as carboxylic acid or sulfonic acid. ]   The image forming method according to claim 4, wherein the toner carrier contains a thermosetting resin in the resin layer.   When the unit composition ratios of the units (1) and (2) contained in the resin are a and b, respectively, b / (a + b) is 0.5 or more and 0.9 or less. The image forming method according to claim 4 or 5.   The image forming method according to any one of claims 4 to 6, wherein the resin is added in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the thermosetting resin.