JP4355642B2 - Black toner - Google Patents

Description

  The present invention relates to a toner used in a recording method using an electrophotographic recording method, an electrostatic recording method, a magnetic recording method, a toner jet recording method, and the like, and a manufacturing method thereof. More specifically, the present invention is applied to a copying machine, a printer, and a fax machine in which a toner image is previously formed on an electrostatic latent image carrier and then transferred onto a transfer material to form an image and fixed under heat pressure to obtain an image. The present invention relates to a toner used and a manufacturing method thereof.

  Conventionally, a number of methods are known as electrophotographic recording methods. In general, a photoconductive substance is used and an electric latent image carrier (hereinafter referred to as “photosensitive member”) is electrically latentized by various means. An image is formed, and then the latent image is developed with a one-component toner or a two-component toner developer to make a visible image by contacting or non-contacting the photoreceptor, and if necessary, a toner is applied to a transfer material such as paper. After the image is transferred, the toner image is fixed on the transfer material by heat, pressure or the like to obtain a copy.

  In recent years, color image forming apparatuses have become widespread. As the toner, for example, an insulating and non-magnetic developer is thinly applied on a developer carrier, and this is triboelectrically charged. A so-called non-magnetic one-component contact development method is often used in which development is carried out by contacting an electrostatic latent image. According to this method, the developer is thinly applied on the developer carrying member, whereby the developer can be triboelectrically charged and a high quality image can be obtained.

  As black pigment particles used for black toner, black pigment particles such as carbon black and magnetite are generally used. Carbon black has good blackness at a relatively low price, but due to its conductivity, the development stability and charging stability of black toner are liable to decrease. In particular, when used for full color, transferability is likely to be different from other color toners such as cyan toner, magenta toner, and yellow toner, and image deterioration is likely to occur.

  On the other hand, magnetite is frequently used for toner for magnetic one-component development, but can also be used for toner for non-magnetic one-component development. Magnetite has a higher resistance value than carbon black, and relatively good development stability and charging stability can be obtained. However, the resistance value still needs to be improved.

  Also, since magnetic toner generally contains a large amount of magnetite, it is difficult to improve the low-temperature fixing performance of the toner. In particular, when used in a full-color image forming apparatus, color toners such as cyan toner, magenta toner, and yellow toner and magnetic toners have different fixing properties, so that the glossiness of the image tends to be uneven.

  In order to solve the above-described problems, techniques for controlling the presence state of magnetite in toner particles have been proposed (see, for example, Patent Documents 1 to 3).

These are intended to achieve both low-temperature fixability and blocking resistance by controlling the arrangement of magnetite in the toner particles. Although the effect may be recognized to some extent, the low-temperature fixability level is still largely different from that of color toners. Further, these magnetites do not contain a Na—Fe—Ti compound and a Fe ₂ O ₃ —FeTiO ₃ solid solution, and are essentially different from the present invention.

  In order to solve the problems associated with these black pigment particles, toners using nonmagnetic or weakly magnetic black pigment particles have been proposed (see, for example, Patent Documents 4 to 7). These toners have a small saturation magnetization value, and can be used in a two-component development system. However, according to the study by the present inventors, these toners have a problem that the blackness is insufficient, the reflection density is sufficiently high, and high-quality black characters and fine lines cannot be expressed.

  For this reason, there has been a demand for a black toner that achieves higher image quality, is excellent in developability and transferability, and is excellent in low-temperature fixability and gloss.

JP 63-089867 A JP 2003-43752 A JP-A-7-209904 Japanese Patent Laid-Open No. 2002-221821 JP 2004-102154 A JP-A-3-137775 JP 2004-54094 A

  The present invention has been made for the purpose of solving the above-mentioned problems of the prior art, is less susceptible to changes in humidity and temperature in the atmosphere, has a stable charging performance, and is used over a long period of use. It is another object of the present invention to provide a black toner that maintains sufficiently high blackness, suppresses fogging, and has excellent image reproducibility.

  Another object of the present invention is to provide a toner capable of forming a stable electrostatic latent image even in a low-temperature and low-humidity environment and having less image defects such as fog due to a decrease in chargeability during a durability test. To do.

  Furthermore, an object of the present invention is to provide a toner that can obtain a sufficient image density, a high image quality, and an excellent image gloss even in a minute isolated dot.

As a result of intensive studies by the present inventors, in the black toner containing black pigment particles having a Na—Fe—Ti compound and Fe ₂ O ₃ —FeTiO ₃ solid solution, the black pigment particles in the black toner have a specific presence. By containing the toner particles in a state at a specific ratio or more, the color development efficiency of the black pigment particles is increased, it is less influenced by environmental fluctuations such as temperature and humidity, has excellent developability and transferability, low temperature fixability and A black toner with excellent image gloss can be obtained.

That is, the present invention is a black toner containing black pigment particles having at least a binder resin, a Na—Fe—Ti compound, and a Fe ₂ O ₃ —FeTiO ₃ solid solution,
In cross-sectional observation of the black toner particles using a transmission electron microscope (TEM), 70% by number or more of the black pigment particles contained in each toner particle has a projected area equivalent diameter of 0 from the surface of the black toner particles. The present invention relates to a black toner containing 40 to 100% by number of toner particles satisfying a structure existing up to twice as deep.

  By using the black toner of the present invention, it is possible to perform printing with high development stability regardless of the environment such as temperature and humidity, excellent low-temperature fixability and glossiness of an image, and excellent blackness.

The black toner of the present invention is a black toner having black toner particles containing black pigment particles having a Na—Fe—Ti compound and a Fe ₂ O ₃ —FeTiO ₃ solid solution, and the black toner has a cross section using a TEM. In observation, a toner satisfying a structure in which 70% by number or more of the black pigment particles contained in each black toner are present from the surface of the black toner to a depth 0.2 times the projected area equivalent diameter. Is a black toner containing 40 to 100% by number.

The Na—Fe—Ti compound and Fe ₂ O ₃ —FeTiO ₃ solid solution used in the present invention have a hydrophilic surface. For this reason, the black toner having black pigment particles containing them still has room for improvement in developability and transferability against environmental fluctuations. Therefore, by arranging the black pigment particles as described above, the toner of the present invention is less affected by the environment such as humidity and temperature in the atmosphere, and the charging stability is improved. As a result, transferability and dot reproducibility are good. Expressed in Further, the Na—Fe—Ti compound and the Fe ₂ O ₃ —FeTiO ₃ solid solution having a large heat capacity with respect to the toner binder resin are unevenly distributed in the toner, whereby the fixability is improved. Further, by finely dispersing the black pigment particles in the toner particles, the hiding power of the black toner is increased, and the black redness shift and blueness shift can be suppressed, and high quality black color is developed. Black toner can be provided.

  That is, in the present invention, the blackness can be improved by making black pigment particles be present on the surface layer of black toner particles as much as possible and finely dispersing. Fixing property when fixing to a transfer material such as paper is improved, and the density of black pigment particles locally increases along the toner surface layer, so that the hiding power can be improved.

  For this reason, the content of the toner particles satisfying the above structure is preferably 60 to 100% by number, more preferably 75 to 100% by number.

  When the content of the toner particles satisfying the above structure is less than 40% by number, the effect of suppressing redness shift and blueness shift may be insufficient in the black hue, and in order to obtain sufficient blackness When the addition amount of the black pigment particles is increased, the fixing property is lowered.

  In the black toner of the present invention, the ratio (B / A) of the iron element content (B) to the carbon element content (A) present on the toner surface, as measured by X-ray photoelectron spectroscopy, is 0.001. It is preferable that it is less than.

  When the black pigment particles in the toner have the above distribution structure, the chargeability and durability are further improved. By making the black toner in which the (B / A) is less than 0.001, and preferably less than 0.0005, the black pigment particles are hardly exposed on the surface of the toner particles, the charging environment stability is excellent. Even in an image forming method in which the toner is pressed against the surface of the electrostatic image bearing member by a charging member, a transfer member, etc., the surface of the electrostatic image bearing member is hardly scraped, and the electrostatic image bearing member can be used for a long time. Scraping and toner fusion can be remarkably reduced.

  When the (B / A) is 0.001 or more, the image density may decrease due to fogging or printing durability particularly in a high temperature and high humidity environment due to moisture absorption and charging leakage of the black pigment particles. Furthermore, since the surface of the electrostatic charge image carrier is easily scraped by the exposed black pigment particles, the photosensitive member is easily scraped.

  In the black toner according to the present invention, the projected area equivalent diameter of the toner is C, and the minimum distance between the black pigment particles and the toner surface in the cross-sectional observation of the toner using a transmission electron microscope (TEM) is D. In this case, it is desirable to contain 50% by number or more of toner particles satisfying the relationship of (D / C) ≦ 0.02.

  By containing 50% by number or more, preferably 65% or more, and more preferably 75% of toner particles satisfying the relationship of (D / C) ≦ 0.02, the surface is substantially composed only of a resin. Nevertheless, the presence of the low-resistance black pigment particles in the vicinity of the surface makes it possible to increase the hiding power of the black toner. In addition, charge-up in a low temperature and low humidity environment can be suppressed, and a decrease in durable concentration, fogging, and the like can be reduced.

  When the toner satisfying the relationship of (D / C) ≦ 0.02 is less than 50% by number, the effect of the Na—Fe—Ti compound may not be sufficiently exhibited, and charge up occurs in a low temperature and low humidity environment. It becomes easy.

  The black pigment particles used in the black toner of the present invention can be contained in an amount of 0.01 to 70% by mass based on the total amount of the toner depending on the purpose. A particularly preferred range is in the range of 8 to 60% by mass, and a more preferred range is 15 to 40% by mass. If the black pigment particle content is less than 8% by mass, the hiding power of the developer may be insufficient. If it exceeds 60% by mass, fine dispersion of the black pigment particles into individual toner particles becomes difficult, and the fixability may be lowered.

  Since the black pigment particle capsule intermediate layer of the present invention has a high density of black pigment particles locally along the toner outer shell during heat melting, the toner hiding power is improved.

The black pigment particles contained in the black toner of the present invention have a Na—Fe—Ti compound and a FeTiO ₃ —Fe ₂ O ₃ solid solution. Specific examples of preferable Na—Fe—Ti compounds include NaFeTi ₃ O ₈ , NaFeTi ₃ O ₈ , NaFeTiO ₄ , Na ₂ Fe ₂ Ti ₃ O ₁₀ , Na _0.75 Fe _0.75 Ti _0.25 O _{2, and the} like.

  The black pigment preferably has a Ti content of 3.0 to 35.0 atomic% with respect to the total Fe content. When it is less than 3.0 atomic%, the toner is likely to be charged up in a low temperature and low humidity environment. On the other hand, if it exceeds 35.0 atomic%, fog is likely to occur in a high temperature and high humidity environment. Preferably, the content is 10.0 to 33.0 atomic%.

  As a preferred method for producing black pigment particles contained in the black toner of the present invention, a step of coating magnetite particles having a number average particle diameter (D1) of 0.01 to 0.20 μm with a titanium compound to form a titanium coating, It can be produced by adding a sodium compound to the titanium coating to form a titanium-sodium mixture, heating and firing the titanium-sodium mixture to form fired particles, and classifying the fired particles. Known magnetite can be used as the magnetite particles used in the above production method. Specifically, titanyl sulfate, titanium tetrachloride, and titanium trichloride can be used as the titanium compound.

  In the step of forming the titanium coating, the titanium compound is added to an aqueous suspension containing magnetite particles, and an alkali carbonate aqueous solution, an alkali hydroxide aqueous solution, or the like can be used.

  Specific examples of the sodium compound that can be used in the step of forming the titanium-sodium mixture include sodium hydroxide, sodium sulfate, sodium carbonate, and sodium chloride.

  In the step of forming the fired particles, the heat firing is preferably performed in an inert gas atmosphere such as nitrogen or argon. The temperature for heating and baking is preferably 700 to 850 ° C.

As for the ratio of the Na—Fe—Ti compound and the Fe ₂ O ₃ —FeTiO ₃ solid solution contained in the black pigment particles, the peak intensity ratio by fluorescent X-ray diffraction is preferably 0.01 to 0.45. By being in the above range, the charging performance of the toner is improved, good image quality is obtained, and blackness is good regardless of the environment such as atmospheric humidity and temperature. When the peak intensity is less than 0.01, the toner is easily charged up in a low temperature and low humidity environment. When the peak intensity exceeds 0.45, the hydrophobicity of the toner is lowered, and fog may be easily generated in a high temperature and high humidity environment. Preferably it is 0.01 to 0.30.

  In the black toner of the present invention, the black pigment particles are preferably hydrophobized and then contained in the toner. It has been difficult to perform the hydrophobic treatment of magnetite or carbon black uniformly, and conventionally, it has been necessary to perform the hydrophobic treatment using a large amount of a treatment agent. Therefore, the influence of the variation in the amount of the processing agent on the toner performance is large. Further, in the small amount processing, the content tends to vary among toners. The black pigment particles used in the present invention are highly reactive with the Na—Fe—Ti compound and the hydrophobizing agent, and can be uniformly treated even in a small amount.

  As a method of hydrophobizing the black pigment particles of the present invention, a method of surface treatment while hydrolyzing the coupling agent while dispersing the black pigment particles to have a primary particle size in an aqueous medium, or in the gas phase A processing method can be used. Compared with the treatment in the gas phase, the hydrophobic treatment method in the aqueous medium is less likely to cause the black pigment particles to coalesce, and the repulsive action between the black pigment particles due to the hydrophobic treatment works. Since the surface treatment is performed in a state of almost primary particles, a highly uniform hydrophobicity is possible.

Examples of the coupling agent that can be used in the present invention include a silane coupling agent and a titanium coupling agent. More preferably used is a silane coupling agent, which is represented by the following general formula (A)
R _m SiY _n (A)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group, and n represents an integer of 1 to 3] Indicates. ]
It is represented by For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethyl Examples include methoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

In particular, the following formula (B)
_{C p H 2p + 1 -Si- (} OC q H 2q + 1) 3 (B)
[Wherein, p represents an integer of 2 to 20, and q represents an integer of 1 to 3]
It is preferable to hydrophobize magnetite in an aqueous medium using an alkyltrialkoxysilane coupling agent represented by:

  In the above formula, when p is smaller than 2, hydrophobizing treatment is easy, but it may be difficult to impart sufficient hydrophobicity. When p is larger than 20, hydrophobicity is sufficient. However, the coalescence of the black pigment particles increases, and the dispersibility of the black pigment particles in the toner particles may decrease. On the other hand, if q is larger than 3, the reactivity of the silane coupling agent may be lowered, and the hydrophobicity may not be sufficiently performed.

  Accordingly, p in the formula represents an integer of 2 to 20 (more preferably, an integer of 3 to 15), and q represents an integer of 1 to 3 (more preferably, an integer of 1 or 2). It is preferred to use a coupling agent. The treatment amount is 0.05 to 20 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the black pigment particles.

  In the present invention, the aqueous medium is a medium containing water as a main component. Specific examples of the aqueous medium include water itself, water added with a small amount of a surfactant, water added with a pH adjusting agent, and water added with an organic solvent. As the surfactant, a nonionic surfactant such as polyvinyl alcohol is preferable. The surfactant is preferably added in an amount of 0.01 to 5% by mass with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid.

  Stirring is preferably performed sufficiently, for example, with a mixer having stirring blades so that the black pigment particles become primary particles in the aqueous medium. Specifically, for example, a high shear mixing device such as an attritor or a TK homomixer can be used.

  Since the black pigment particles obtained in this way are uniformly hydrophobized on the surface, when used as a toner material, the dispersibility in the toner is very good and the aggregation of the black pigment particles in addition is suppressed. Therefore, even better development stability and charging stability can be obtained.

  The black pigment particles preferably have a Na atom content of 0.10 to 3.00 atomic% with respect to Fe atoms determined by fluorescent X-ray diffraction. When the amount of Na atoms contained in the black pigment particles is in the above range, the blackness is improved and the charging performance of the toner of the present invention is further improved.

  When the content of Na atoms with respect to Fe atoms is less than 0.10 atomic%, a reddish shift tends to occur as in the case of conventional iron-based black pigments, and a high-quality black color cannot be obtained. On the other hand, if it exceeds 300 atomic%, the charging performance of the toner in a low-temperature and low-humidity environment is lowered, and image fogging tends to occur.

  The black pigment particles contained in the black toner of the present invention preferably have a hydrophobicity index of 75 or more. In the present invention, the hydrophobization index is an index obtained by simply quantifying the affinity between the black pigment particles contained in the black toner and the binder resin, and the larger the value, the higher the affinity. When the hydrophobization index is in the above range, the constitution of the present invention is satisfactorily achieved, and the dispersibility, blackness, and charging stability of the black pigment particles are further improved. When the hydrophobization index is less than 75, black pigment particles are exposed on the surface of the toner particles, and transferability under a high temperature and high humidity environment may be deteriorated. Moreover, durability stability may fall.

The black toner of the present invention preferably has a saturation magnetization value of 1.2 to 7.5 emu / g (Am ² / kg) in an external magnetic field of 5,000 oersted (398 kA / m). The reason for this is not clear, but according to the study by the present inventors, it is considered that the black toner has a magnetism in the above range, so that some binding force acts between the toners and the scattering of the toner in the transfer is suppressed. It is done. Further, when black toner is magnetized, a binding force is generated between the toners, and fogging and scattering are further suppressed. If a magnetic developing roller is used, fogging can be suppressed. When a restricting member having magnetism is used, the current pressure on the toner can be reduced, and stress on the toner is reduced and its durability is improved. When a magnetic transfer member is used, scattering can be suppressed. When a magnetic fixing member is used, electrostatic offset can be prevented.

The black pigment particles contained in the black toner of the present invention may have a saturation magnetization value of 1.2 to 7.5 emu / g (Am ² / kg) at an external magnetic field of 5,000 Oersted (398 kA / m). desirable. When the magnetization value of the black pigment particles is in the above range, the above-described toner magnetization value can be achieved without using a special additive for adjusting the magnetization value of the black toner.

  In the black toner of the present invention, the weight average particle diameter is preferably 2 to 10 μm. When the weight average particle size of the toner exceeds 10 μm, the reproducibility of the fine dot image is lowered, and the toner configuration of the present invention is more susceptible to particle size fluctuations in durable use. In some cases, charging stability of the toner under the harsh environment obtained cannot be sufficiently exhibited. On the other hand, when the weight average particle size of the toner is smaller than 2 μm, even if the special structure of the present invention is used, deterioration of the external additive is likely to occur due to the decrease in fluidity, fogging due to poor charging, and insufficient density. The problem is likely to occur.

  In the black toner of the present invention, a remarkable effect on the image, such as improvement in charging stability and fluidity, appears on the image when the weight average particle diameter is 2 to 10 μm, more preferably 3 to 8 μm. Furthermore, 3.0 to 6.0 μm is preferable from the viewpoint of higher image quality.

  The black toner of the present invention has a molecular weight peak (Mp) of 6,000 to 60,000 in the molecular weight distribution by THF-soluble GPC, and the black toner has a softening point of 70 to 120 ° C. by a flow tester. Preferably there is.

  Although the black pigment particles have a high blackness like carbon black, the volume occupied by the black pigment particles in the toner is larger than the black pigment particles having a low resistance and a small particle size. It tends to decline. When the molecular weight peak (Mp) and the softening point are in the above ranges, the glossiness is increased and a high-quality image is obtained, and the blackness is further improved.

  When the Mp is less than 6,000, the softening point is less than 70 ° C., and when the fixing temperature is high, the paper may soak into the paper and the glossiness may be lowered. When Mp exceeds 60,000, the softening point exceeds 120 ° C., and the glossiness may decrease.

  The acid value of the THF soluble component of the black toner of the present invention is preferably 0.1 to 50.0 mgKOH / g. By being in the above range, the dispersibility of the black pigment particles in the toner is improved, the charging performance of the toner is improved, and good image quality is obtained regardless of the environment such as humidity and temperature in the atmosphere. When the acid value is less than 0.1 (B / A) ≦ 0.001, it may be difficult to satisfy. Further, when the acid value exceeds 50.0 ((D / C)) ≦ 0.02, it may be difficult to satisfy. Preferably it is 0.5 to 50.0 mgKOH / g.

  Next, materials used for the toner of the present invention and a method for producing the same will be described.

  As the binder resin used in the black toner of the present invention, various resins conventionally known as binder resins for electrophotography are used. Among them, (a) polyester resin, (b) polyester unit and vinyl-based resin are used. Hybrid resin having polymer unit, (c) mixture of hybrid resin and vinyl copolymer, (d) mixture of hybrid resin and polyester resin, and (e) polyester resin and vinyl copolymer (F) a polyester resin, a hybrid resin having a polyester unit and a vinyl copolymer unit, a mixture of a vinyl copolymer, and (g) a vinyl copolymer. It is preferable that the main component is a resin.

  When a polyester-based resin is used as the binder resin, a polyhydric alcohol and a polyvalent carboxylic acid, a polyvalent carboxylic acid anhydride, a polyvalent carboxylic acid ester, or the like can be used as a raw material monomer. Specifically, for example, as the dihydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2 -Bisphenol A alkylene oxide adducts such as bis (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, Opentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A And hydrogenated bisphenol A.

  Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Can be mentioned.

  As the polyvalent carboxylic acid component, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or anhydrides thereof; alkyl dicarboxylic acids such as oxalic acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof; Succinic acid substituted with 6 to 12 alkyl groups or anhydrides thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or anhydrides thereof; n-dodecenyl succinic acid, isododecenyl succinic acid, etc. It is done.

  Among them, in particular, a bisphenol derivative represented by the following general formula (1) is used as a diol component, and a carboxylic acid component (for example, fumaric acid) composed of a divalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof. Polyester resins obtained by condensation polymerization using maleic acid, maleic anhydride, phthalic acid, terephthalic acid) as acid components are preferable as color toners because they have good charging characteristics.

〔式中、Ｒ¹及びＲ²は炭素数２乃至５個のアルキレン基を示し、Ｘ及びＹが正数を示し、Ｘ＋Ｙは２乃至６を示す。〕

[Wherein, R ¹ and R ² represent an alkylene group having 2 to 5 carbon atoms, X and Y represent a positive number, and X + Y represents 2 to 6. ]

  Examples of the trivalent or higher polyvalent carboxylic acid component for forming a polyester resin having a crosslinking site include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2 1,4-naphthalenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof.

  The amount of the trivalent or higher polyvalent carboxylic acid component is preferably 0.1 to 1.9 mol% based on the total monomer. Furthermore, as a binder resin, a polyester unit that has an ester bond in the main chain and is a polycondensate of polyhydric alcohol and polybasic acid, and a vinyl polymer unit that is a polymer having an unsaturated hydrocarbon group In the case of using a hybrid resin having the above, it is possible to expect further improved wax dispersibility, low-temperature fixability, and offset resistance. The hybrid resin used in the present invention means a resin in which a vinyl polymer unit and a polyester unit are chemically bonded. Specifically, it is a resin formed by a transesterification reaction between a polyester unit and a vinyl polymer unit obtained by polymerizing a monomer having a carboxylic acid ester group such as (meth) acrylic acid ester, preferably a vinyl polymer. A graft copolymer (or block copolymer) having a trunk polymer and a polyester unit as a branch polymer.

  Examples of the vinyl monomer for producing the vinyl polymer include styrene; o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2, 4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn -Styrene such as dodecylstyrene, p-methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene and derivatives thereof; ethylene, propylene, butylene, isobutylene Styrene unsaturated monoolefins such as butadiene and isoprene Saturated polyenes; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, methacrylic acid Propyl, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate Α-methylene aliphatic monocarboxylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid-n-butyl, acrylic acid isobutyl, acrylic acid-n-octyl, acrylic acid dode Acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, acrylic esters such as phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, Vinyl ketones such as vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; Vinyl naphthalenes; Acrylonitrile, methacrylonitrile, acrylamide And acrylic acid or methacrylic acid derivatives.

  In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl 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 half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester unsaturated dibasic acid half ester; dimethylmaleic acid, dimethyl fumaric acid unsaturated dibasic acid ester; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Furthermore, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl polymer unit of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. Examples of the crosslinking agent used in this case include divinylbenzene and divinylnaphthalene as aromatic divinyl compounds; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate and 1,3-butylene glycol diene. Acrylates, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylates of the above compounds with methacrylates; Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene. Examples include lenglycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds replaced with methacrylate; diacrylates linked by chains containing aromatic groups and ether bonds Examples of the compounds include polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate and the like The thing which replaced the acrylate of the compound of this with the methacrylate is mentioned.

  As polyfunctional cross-linking agents, pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and acrylates of the above compounds are replaced by methacrylate; triallylcia Examples include nurate and triallyl trimellitate.

  The hybrid resin used in the present invention preferably contains a monomer component capable of reacting with both resin components in one or both of the vinyl polymer unit component and the polyester unit. Examples of the monomer constituting the polyester unit that can react with the vinyl polymer unit include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Among the monomers constituting the vinyl polymer unit, those that can react with the polyester unit include those having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

  As a method of obtaining a reaction product of a vinyl polymer unit and a polyester unit, a polymer containing a monomer component capable of reacting with each unit is present, and a polymerization reaction of one or both resins is performed. The method obtained by

  Examples of the polymerization initiator used for producing the vinyl polymer of the present invention include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethyl). Valeronitrile), 2,2′-azobis (-2,4-dimethylvaleronitrile), 2,2′-azobis (-2methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1 , 1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl -4-methoxyvaleronitrile, 2,2'-azobis (2-methyl-propane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclo Ketone peroxides such as xanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroper Oxide, di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl Peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate Di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxy Oxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy 2-ethylhexanoate, di-t-butyl peroxyhex Hydro terephthalate, di -t- butyl peroxy azelate and the like.

  Examples of the production method capable of preparing the hybrid resin used in the toner of the present invention include the following production methods (1) to (6).

  (1) A method in which a vinyl polymer unit, a polyester unit and a hybrid resin component are blended after production, and the blended product is produced by dissolving and swelling in an organic solvent (for example, xylene) and then distilling off the organic solvent. The For the hybrid resin component, a vinyl polymer and a polyester resin are separately manufactured, dissolved and swollen in a small amount of an organic solvent, an esterification catalyst and an alcohol are added, and the ester exchange reaction is performed by heating. Synthesized ester compounds can be used.

  (2) A method for producing a polyester unit and a hybrid resin component in the presence of a vinyl polymer after the production thereof. The hybrid resin component is produced by a reaction between a vinyl polymer (a vinyl monomer can be added if necessary) and any one of a polyester monomer (alcohol, carboxylic acid) and polyester, or a reaction with both. Also in this case, an organic solvent can be appropriately used.

  (3) A method for producing a vinyl polymer and a hybrid resin component in the presence of a polyester unit after the production thereof. The hybrid resin component is produced by a reaction between one or both of a polyester unit (a polyester monomer can be added if necessary) and a vinyl monomer.

  (4) After the production of the vinyl polymer unit and the polyester unit, the hybrid resin component is produced by adding one or both of the vinyl monomer and the polyester monomer (alcohol, carboxylic acid) in the presence of these polymer units. Is done. Also in this case, an organic solvent can be appropriately used.

  (5) After producing the hybrid resin component, one or both of a vinyl monomer and a polyester monomer (alcohol, carboxylic acid) are added, and at least one of addition polymerization and polycondensation reaction is performed, thereby producing a vinyl resin. Polymer units and polyester units are produced. In this case, as the hybrid resin component, those produced by the production methods (2) to (4) can be used, and those produced by a known production method can be used as necessary. Furthermore, an organic solvent can be used as appropriate.

  (6) A vinyl polymer unit, a polyester unit, and a hybrid resin component are produced by mixing a vinyl monomer and a polyester monomer (alcohol, carboxylic acid, etc.) and continuously performing addition polymerization and condensation polymerization reaction. Furthermore, an organic solvent can be used as appropriate.

  In the above production methods (1) to (5), a polymer unit having a plurality of different molecular weights and crosslinking degrees can be used for the vinyl polymer unit and the polyester unit.

  The binder resin contained in the toner of the present invention includes a mixture of the polyester resin and a vinyl polymer, a mixture of the hybrid resin and a vinyl polymer, the polyester resin and the hybrid resin. A mixture of vinyl polymers may be used.

  The toner of the present invention preferably has 5 to 90% by mass of tetrahydrofuran (THF) insoluble matter. More preferably, it is 5-70 mass%, More preferably, it is 5-65 mass%. This is because the balance between storage stability performance, development stability performance and low-temperature fixing performance is further improved.

  As the charge control agent contained in the toner in the present invention, known ones can be used, and in particular, an aromatic carboxylic acid metal compound that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount. Is preferred.

  Negative charge control agents include salicylic acid metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, calixarene, etc. Is available. As the positive charge control agent, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, an imidazole compound, or the like can be used. Among these, 3,5-di-tertiary butyl salicylate is particularly preferable because the charge amount rises quickly. The charge control agent may be added internally or externally to the toner particles. The total amount of the charge control agent added is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  In the present invention, as the fluidizing agent externally added to the black toner particles, known ones can be used. In particular, the external addition of the fluidity improving agent improves the image quality, under a high temperature environment. It is preferable in terms of storage stability. As the fluidity improver, inorganic fine powders such as silica, titanium oxide, and aluminum oxide are preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof.

  Examples of the hydrophobizing agent include coupling agents such as silane compounds, titanate coupling agents, aluminum coupling agents, and zircoaluminate coupling agents.

  Specifically, for example, a silane compound represented by the general formula (2) is preferable. For example, hexamethyldisilazane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, Examples thereof include trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane. The processing amount 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 inorganic fine powder.

R _m SiY _n (2)
[Wherein, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group, and n represents an integer of 1 to 3] Indicates. ]

  In the present invention, the alkylalkoxysilane represented by the general formula (3) is particularly suitable for the hydrophobizing treatment of the surface of the fluidizing agent. In the alkylalkoxysilane, when n is less than 4, the treatment is easy, but the degree of hydrophobicity is low, which is not preferable. When n is larger than 12, hydrophobicity is sufficient, but coalescence of titanium oxide fine particles increases, and fluidity imparting ability tends to decrease. When m is larger than 3, the reactivity of the alkylalkoxysilane is lowered and it becomes difficult to perform hydrophobicity well.

  More preferably, in the alkylalkoxysilane, n is 4 to 8, and m is 1 to 2. The treatment amount of the alkylalkoxysilane 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 inorganic fine powder.

_{C n H 2n + 1 -Si- (} OC m H 2m + 1) 3 (3)

  The hydrophobizing treatment of the fluidizing agent may be performed alone or in combination of two or more. For example, one type of hydrophobizing agent may be hydrophobized alone, or two hydrophobizing agents at the same time, or one hydrophobizing agent and another hydrophobizing agent. Further, a hydrophobizing treatment may be performed.

  The fluidizing agent is preferably added in an amount of 0.01 to 5 parts by mass and more preferably 0.05 to 3 parts by mass with respect to 100 parts by mass of the toner particles.

  As the colorant used in the other color toner used together with the black toner of the present invention, the following are used.

  Examples of the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 176, 180, 181 and 191 are preferably used.

  Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48; 2, 48; 3, 48; 4, 57; 1, 81; 1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 22254, C.I. I. Pigment violet 19 is particularly preferred.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, and 66 can be used alone.

  In order to adjust the color tone of the black toner of the present invention, the colorant may be used in combination. In that case, the range of 0.01 to 10.00% by mass with respect to the black pigment particles is preferable.

In order to improve charging stability, developability, fluidity, and storage stability, it is preferably selected from silica fine powder, alumina fine powder, titania fine powder, and fine powders of double oxides thereof. In particular, silica fine powder is preferable. As the silica, dry silica produced by vapor phase oxidation of silicon halide or alkoxide, and wet silica produced from alkoxide, water glass or the like can be used. Dry silica is preferred because it has few silanol groups on the surface and in the silica fine powder, and few production residues such as Na ₂ O and SO ₃ ^2- . In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. You may do it.

  The black toner shape of the present invention preferably has an average circularity in the range of 0.920 to 0.995 for particles having an equivalent circle diameter of 2 μm or more in the toner. More preferably, it is 0.930 to 0.995. When the average circularity is less than 0.920, transferability, particularly transfer efficiency, is poor, graininess in a low density region is poor, and an image with a rough feeling may be obtained. On the other hand, if the average circularity is greater than 0.995, the cleaning of the photosensitive drum may cause an image defect such as poor cleaning such as passing through the cleaning blade because the shape is too spherical.

  The average circularity of the black toner of the present invention can also be adjusted by using a surface modifying apparatus described later.

  In order to reduce the toner adhesion to the non-image area on the electrostatic image bearing member and the amount of residual toner, it is necessary that the chargeability of the toner particles is sufficient and uniform. Furthermore, when using a toner having a small particle diameter from the viewpoint of improving the image quality, the adhesion force of the toner particles increases, so the shape of the toner particles has a great influence on the toner adhesion to the non-image area on the electrostatic charge image carrier. Effect. In other words, the closer the toner particles are to a spherical shape and the more uniform the shape, the smaller the adhesion area of the particles, the less toner adhesion to the non-image area on the electrostatic image bearing member and the remaining amount of transfer residual toner, high image quality and durability Stability is possible.

  In addition, the black toner of the present invention is sufficiently charged, and as described above, the toner adhesion is reduced, so that the transfer efficiency of the toner from the electrostatic charge image carrier to the transfer material such as paper is improved. Is greatly improved. This can be said to be an important toner performance for achieving high resolution as well as reproducibility of a minute dot image. Therefore, in the black toner of the present invention, it is preferable that the average circularity of the toner is 0.970 or more, which enables further high image quality and high stability.

  The black toner of the present invention is desirably produced by a granulation method in an aqueous medium. Specific examples of the production method desirable in the present invention include suspension polymerization method, cohesion fusion method, dissolution suspension method, dispersion polymerization method and the like.

  When the toner of the present invention is produced by a pulverization method, a known method can be used. As a known method, for example, a binder resin, a release agent, a charge control agent, and in some cases, components such as black pigment particles and other additives necessary for toner and other additives are mixed in a mixer such as a Henschel mixer or a ball mill. After sufficiently mixing, the materials are melt-kneaded using a heat kneader such as a heating roll, a kneader, and an extruder to mutually melt the resins. In the toner, other toner materials such as magnetite are dispersed or dissolved, and after cooling, solidification, and pulverization, classification is performed, in addition, surface treatment with black pigment particles is performed, and then the toner is further treated with resin particles and the like. Get particles. A toner can be obtained by adding and mixing fine powder or the like to the obtained toner particles as necessary. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier from the viewpoint of production efficiency.

  The pulverization step can be performed using a known pulverizer such as a mechanical impact type or a jet type. In order to obtain a developer having a specific circularity according to the present invention, it is preferable to further pulverize by applying heat or to add a mechanical impact in an auxiliary manner. Further, a hot water bath method in which finely pulverized (classified as necessary) toner particles are dispersed in hot water, a method of passing in a hot air stream, or the like may be used.

  As a method of applying a mechanical impact force, for example, there is a method using a mechanical impact type pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Industry. Also, like devices such as Hosokawa Micron's Mechano-Fusion System and Nara Machinery's Hybridization System, the toner is pressed against the inside of the casing by centrifugal force with high-speed rotating blades, and the force of compression force, friction force, etc. A method of applying a mechanical impact force to the toner may be used.

  When processing with mechanical impact is applied, setting the ambient temperature during processing to a temperature near the glass transition point Tg of the toner (that is, a temperature range of ± 30 ° C. with respect to the glass transition point Tg) prevents aggregation. From the viewpoint of productivity. More preferably, the treatment at a temperature in the range of ± 20 ° C. with respect to the glass transition point Tg of the toner is particularly effective for improving the transfer efficiency.

  Furthermore, the toner of the present invention is a method of obtaining a spherical toner by atomizing a molten mixture into air using a disk or a multi-fluid nozzle, or a water-based organic solvent that is soluble in a monomer and insoluble in a polymer obtained. The toner is produced using a dispersion polymerization method in which toner is directly produced by using emulsion, or an emulsion polymerization method represented by a soap-free polymerization method in which toner is produced by direct polymerization in the presence of a water-soluble polar polymerization initiator. It can also be produced by a method such as a dissolution suspension method or an emulsion aggregation method.

  As a particularly preferable production method, in a toner production method (hereinafter referred to as a polymerization method) obtained by directly polymerizing a monomer system in an aqueous medium, between the polar and nonpolar components from the viewpoint of affinity with the aqueous medium. Since localization / separation is likely to occur, the black pigment particle structure of the present invention can be obtained in one step, which is preferable. In particular, in the present invention, by using a small amount of the above polar compound, the stability of droplets during polymerization can be improved, and the particle size distribution becomes sharp, which is more preferable in terms of yield.

  The following are mentioned as a polymerizable monomer which comprises the polymerizable monomer type | system | group which is a raw material of binder resin used for this invention.

  Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, and p-ethylstyrene; methyl acrylate, ethyl acrylate, Acrylic esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate Class: Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenolic methacrylate , Dimethylaminoethyl methacrylate, such as methacrylic acid esters of diethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide.

  These monomers can be used alone or in admixture of two or more. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or mixed with other monomers from the viewpoint of developing characteristics and durability of the toner.

  In addition, the toner of the present invention preferably contains 0.5 to 50% by mass of a release agent with respect to the binder resin. Usually, a toner image is transferred onto a transfer material in a transfer process, and this toner image is then fixed on the transfer material with energy such as heat and pressure, whereby a semi-permanent image is obtained. As a fixing method at this time, a heat roll type fixing is generally used. As described above, if a toner having a weight average particle diameter of 10 μm or less is used, a very high-definition image can be obtained. When a transfer material such as paper is used, the toner particles having a small diameter enter the gap between the fibers of the paper, and heat reception from the heat fixing roller becomes insufficient, and low temperature offset tends to occur. However, in the toner of the present invention, by containing an appropriate amount of wax as a release agent, it is possible to prevent the photoconductor from being scraped while achieving both high resolution and offset resistance.

  Examples of the wax usable in the toner of the present invention include petroleum wax such as paraffin wax, microcrystalline wax, and petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon wax and derivatives thereof according to the Fischer-Tropsch method; Polyolefin waxes and derivatives thereof; natural waxes such as carnauba wax and candelilla wax and derivatives thereof. Derivatives here include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, and animal waxes can also be used.

  Among these wax components, the DSC curve measured by a differential scanning calorimeter preferably has a maximum endothermic peak in the region of 40 to 110 ° C. when the temperature is raised, and has a maximum endothermic peak in the region of 45 to 90 ° C. What has it is more preferable. By having the maximum endothermic peak in the above temperature range, it is possible to effectively exhibit releasability while greatly contributing to low-temperature fixing. When this maximum endothermic peak is less than 40 ° C., the self-cohesive force of the wax component becomes weak, and as a result, the high temperature offset resistance deteriorates. On the other hand, when the maximum endothermic peak exceeds 110 ° C., the fixing temperature increases and low temperature offset tends to occur. Furthermore, when granulating / polymerizing in an aqueous medium and directly obtaining a toner by the polymerization method, if this maximum endothermic peak temperature is high, the wax component is mainly precipitated during granulation such as when a large amount is added. May occur.

  In the toner of the present invention, the content of the wax component is preferably in the range of 0.5 to 50% by mass with respect to the binder resin. If the content of the wax component is less than 0.5% by mass, the effect of suppressing the low temperature offset is poor, and if it exceeds 50% by mass, the long-term storage stability is deteriorated and the dispersibility of other toner materials is deteriorated. The fluidity of the liquid and the image characteristics are likely to deteriorate.

  The toner of the present invention may contain a charge control agent in order to stabilize the charge characteristics. As the charge control agent, known ones can be used, but a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable.

  Further, when the toner is produced by a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific compounds include, as negative charge control agents, metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid, metal salts or metal complexes of azo dyes or azo pigments, sulfonic acids Alternatively, a polymer compound having a carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, or a calixarene can be used. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, a nigrosine compound, and an imidazole compound. These charge control agents are preferably used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer. However, the developer related to the image forming method of the present invention does not require the addition of a charge control agent, and the toner can be applied to the toner by actively utilizing the frictional charging of the developer with the layer pressure regulating member or the developer carrier. If sufficient chargeability can be imparted, it is not always necessary to include a charge control agent in the toner.

Further, the black pigment particles used in the toner of the present invention may contain elements such as phosphorus, cobalt nickel, copper, magnesium, manganese, aluminum, and silicon. The black pigment particles preferably have a BET specific surface area by nitrogen adsorption method of preferably 2 to 30 m ² / g, more preferably 3 to 28 m ² / g. Further, those having a Mohs hardness of 5 to 7 are preferred.

  Further, the black pigment particles may be octahedral, hexahedral, spherical, needle-shaped, scale-shaped, etc., but those having low anisotropy such as octahedral, hexahedral, spherical, and indeterminate form the image density. It is preferable in terms of enhancement. Such a shape can be confirmed by a scanning electron microscope (SEM) or the like. The black pigment particles preferably have a volume average particle diameter of 0.010 to 0.30 μm.

  In the black toner of the present invention, a polar compound having a saponification value of 20 to 200 is preferably added to the black pigment particles of the present invention.

  The polar compound having a saponification value of 20 to 200 in the present invention is a resin having a carboxylic acid derivative group such as acrylic acid, methacrylic acid or abietic acid, or a sulfur acid group such as sulfonic acid or sulfuric acid group, or a modified product thereof. Any specific monomer component that constitutes such a resin can be used as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-acrylate. Acrylates such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, N-propyl methacrylate, n-methacrylic acid Methacrylic acid esters such as chill, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; maleic acids such as maleic anhydride and maleic acid half ester; Sulfuric acid groups such as sulfonic acid; abietic acid and the like are exemplified.

  Among these compounds, a resin having a maleic acid component is preferable because it can exhibit the effects of the present invention even in a very small amount, and it is preferable because it does not impair the chargeability and is excellent in compatibility with the binder resin. In particular, a maleic anhydride copolymer represented by the following general formula (1) and / or (2) or a ring-opening compound thereof is particularly preferable, and the effects of the present invention are further exhibited.

（各式中、Ａはアルキル基又はアルキレン基を示し、Ｒは水素原子又は炭素数１乃至２０のアルキル基を示す。ｎは１乃至２０の整数を示し、ｘ、ｙおよびｚはそれぞれ各成分の共重合比を示す。）

(In each formula, A represents an alkyl group or an alkylene group, R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, n represents an integer of 1 to 20, and x, y, and z represent each component. The copolymerization ratio of

  The content of the polar compound in the toner is preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the binder resin. If the content of the polar compound is less than 0.001 part, the effect of the present invention will not be exhibited, and if it exceeds 10 parts, the absolute value of the charge amount is likely to decrease due to charge leakage, and fog and durability image density may be reduced. Decline is likely to occur.

  Moreover, the average molecular weight of the high molecular polymer containing these polar functional groups is preferably 3000 or more. When the molecular weight is less than 3000, particularly 2000 or less, the present polymer is likely to concentrate near the surface, which is unfavorable because it tends to adversely affect developability and blocking resistance. In addition, if a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer constituting the binder resin is dissolved in the monomer and polymerized, a wide molecular weight distribution and offset resistance can be obtained. High toner can be obtained.

  When the toner of the present invention is produced by a polymerization method, a polymerization initiator having a half-life of 0.5 to 30 hours during the polymerization reaction is used in an addition amount of 0.5 to 20% by mass of the polymerizable monomer. When the polymerization reaction is carried out, a polymer having a maximum between 10,000 and 100,000 is obtained, and the toner can be provided with desirable strength and appropriate melting characteristics. Examples of polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile ), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Peroxide polymerization initiators such as cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide.

  In the present invention, a crosslinking agent may be added, and a preferable addition amount is 0.001 to 15% by mass of the polymerizable monomer.

  Of the above polymerization methods, the production of toner by suspension polymerization generally involves the above-described toner composition, that is, a polymerizable compound and a black pigment particle, a polar compound having a saponification value of 20 to 200 (or a constituent thereof). Monomer components), mold release agents, plasticizers, binders, charge control agents, crosslinking agents, and other components necessary as toners and other additives, for example, to reduce the viscosity of the polymer produced by the polymerization reaction An organic solvent, a dispersant, and the like are added as appropriate, and the mixture is uniformly dissolved or dispersed by a dispersing machine such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic dispersing machine. The monomer system thus obtained is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size distribution of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size at a stretch. The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium.

  Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  After granulation, stirring may be performed using an ordinary stirrer to such an extent that the particle state is maintained and particle floating and sedimentation are prevented. In the present invention, the pH in the aqueous medium prior to the addition of the monomer system is important in order to appropriately segregate the black pigment particles near the surface of the toner particles using a polar compound having a specific saponification value. In order to obtain a toner having black pigment particles of the present invention, the pH is preferably 4 to 10.5. If the pH is less than 4, the effect of the polar compound almost disappears, so that a large amount of polar substance needs to be added, and the effect of lowering the charge amount, broadening of the particle size distribution, and the like occurs. On the other hand, if the pH exceeds 10.5, the addition of the polar compound rather promotes the exposure of some black pigment particles, making it difficult to maintain the structure control of the present invention.

  In the suspension polymerization method used in the present invention, known surfactants and organic / inorganic dispersants can be used as dispersion stabilizers. In particular, inorganic dispersants are less likely to produce harmful ultrafine powders, and their steric hindrance prevents dispersion. Therefore, even if the reaction temperature is changed, the stability is not easily lost, the washing is easy and the toner is not adversely affected. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; calcium metaoxalate, calcium sulfate, and sulfuric acid. Inorganic salts such as barium; inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina.

  These inorganic dispersants are preferably used alone or in combination of two or more, with respect to 100 parts by weight of the polymerizable monomer. When aiming at a more finely divided toner having an average particle diameter of 5 μm or less, 0.001 to 0.1 parts by mass of a surfactant may be used in combination.

  Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, and potassium stearate.

  When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed with high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At the same time, a water-soluble sodium chloride salt is produced as a by-product. However, if a water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and an ultrafine toner based on emulsion polymerization is produced. Since it becomes difficult to generate | occur | produce, it is more convenient. However, since this sodium chloride salt becomes an obstacle when removing the remaining polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalinate with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolving with an acid or alkali after completion of the polymerization.

  In the polymerization step, the polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. When the polymerization is carried out in this temperature range, the release agent or wax to be sealed inside is precipitated by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, it is possible to raise the reaction temperature to 90 to 150 ° C. at the end of the polymerization reaction.

  In the toner of the present invention, it is preferable that an inorganic fine powder or a hydrophobic inorganic fine powder is externally added to the toner particles and mixed as a fluidity improver. For example, titanium oxide fine powder, silica fine powder, and alumina fine powder are preferably added and used, and silica fine powder is particularly preferred.

The inorganic fine powder used in the toner of the present invention has a specific surface area by nitrogen adsorption measured by the BET method of 30 m ² / g or more, and particularly in the range of 50 to 400 m ² / g gives good results. Is preferable.

  Furthermore, the toner of the present invention may have an external additive other than the fluidity improver mixed with the toner particles as necessary.

For example, for the purpose of improving cleaning properties, the primary particle diameter exceeds 30 nm (preferably the specific surface area is less than 50 m ² / g), more preferably the primary particle diameter is 50 nm or more (preferably the specific surface area is 30 m ^2). It is also a preferable form to add inorganic particles or organic particles that are nearly spherical at less than / g) to the toner particles. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, and spherical resin particles are preferably used.

  Still other additives such as lubricant powders such as fluororesin powder, zinc stearate powder, polyvinylidene fluoride powder; or abrasives such as cerium oxide powder, silicon carbide powder, strontium titanate powder; anti-caking agent; or such as carbon Conductivity imparting agents such as black powder, zinc oxide powder and tin oxide powder; organic fine particles having opposite polarity and inorganic fine particles can also be added in small amounts as developability improvers. These additives can also be used after hydrophobizing the surface.

  The external additive as described above may be used in an amount of 0.1 to 5 parts by mass (preferably 0.1 to 3 parts by mass) with respect to 100 parts by mass of the toner.

  The method for measuring various physical property data in the present invention is described in detail below.

(1) Ratio of iron element content (B) to carbon element content (A) present on the toner surface (B / A)
The ratio (B / A) of the iron element content (B) to the carbon element content (A) present on the toner surface in the present invention is calculated by surface composition analysis by X-ray photoelectron spectroscopy (ESCA). .

  Specifically, for example, it can be determined under the following measurement conditions.

Equipment used: 1600S type X-ray photoelectron spectrometer manufactured by PHI (Physical Electronics Industries, Inc.) Measurement conditions: X-ray source MgKα (400 W)
Spectral region 800μmφ

  From the measured peak intensity of each element, the surface atomic concentration (atomic%) is calculated using a relative sensitivity factor provided by PHI.

  Toner is used as a measurement sample. When an external additive is added to the toner, the toner is washed with a solvent that does not dissolve the toner, such as isopropanol, and the measurement is performed after removing the external additive. .

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

  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).

  In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity.

  The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following equation, where ci is the circularity (center value) at the dividing point i of the particle size distribution and m is the number of measured particles.

  In addition, “FPIA-2100”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity and the circularity standard deviation. The degree 0.4 to 1.0 is divided into classes equally divided every 0.01, and the average circularity and the circularity standard deviation are calculated using the center value of the division points and the number of measured particles.

  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 in-machine temperature of 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 particles, the flow type particle image measuring device is used, and the concentration of the dispersion is readjusted so that the toner particle concentration at the time of measurement is 3000 to 10,000 particles / μl. Measure more than one. After the measurement, using this data, data having an equivalent circle diameter of less than 2 μm is cut to determine the average circularity of the toner particles.

  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 is improved by improving the processing resolution of the captured image (256 × 256 → 512 × 512), thereby achieving more reliable capture of fine particles. Therefore, when it is necessary to measure the shape more accurately as in the present invention, the FPIA 2100 that can obtain information on the shape more accurately is more useful.

(3) Weight average particle diameter of toner A Coulter Counter TA-II type (manufactured by Coulter Co.) is used as a measuring device, an interface (manufactured by Nikkiki) for outputting number distribution and volume distribution and a personal computer are connected, and an electrolytic solution Prepare 1% NaCl aqueous solution using primary sodium chloride. As such an electrolytic solution, for example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 mL of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 mL of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using the Coulter counter TA-II, the volume and number of toners are measured by measuring the volume and number of toners using a 100 μm aperture. The volume distribution and number distribution of particles of 40 μm to 40 μm are calculated. Then, the weight-based weight average diameter D4 obtained from the number average particle diameter (D1) volume distribution (the median value of each channel is the representative value for each channel), and the weight-based weight of 12.7 μm or more obtained from the volume distribution Find the distribution.

(4) Measuring method of projected area equivalent diameter C of toner, distance D between black pigment particles and toner surface and (D / C) Temperature after sufficiently dispersing particles to be observed in room temperature curable epoxy resin The cured product obtained by curing for 2 days in an atmosphere of 40 ° C. is observed as it is or as a sample that is frozen and shaped into a thin piece by a microtome equipped with diamond teeth.

  A specific method for determining the ratio of the number of corresponding particles is as follows. For particles for determining (D / C) by TEM, the equivalent circle diameter (referred to as “projected area equivalent diameter”) is obtained from the cross-sectional area of the toner obtained from the micrograph, and this value is obtained from the Coulter counter. The particles included in the width of ± 10% of the number average particle diameter determined by the method described later are used. For the corresponding 100 particles, the minimum value (D) of the distance between the toner particle surface and the black pigment particle surface is measured to obtain (D / C), and the (D / C) value of particles having a value of 0.02 or less is obtained. Calculate the percentage.

(5) Method for measuring acid value The acid value is determined as follows. Basic operation conforms to JIS-K0070. Specifically, the test is performed by the following method.

(5-1) Reagent (a) Solvent Ethyl ether-ethyl alcohol mixed solution (1 + 1 or 2 + 1) or benzene-ethyl alcohol mixed solution (1 + 1 or 2 + 1), these solutions are N / 10 with phenolphthalein as an indicator just before use. Neutralize with potassium hydroxide ethyl alcohol solution.

(B) Phenolphthalein solution 1 g of phenolphthalein is dissolved in 100 mL of ethyl alcohol (95 v / v%).

(C) N / 10 potassium hydroxide-ethyl alcohol solution Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 v / v%) to 1 L, leave it for 2 to 3 days, and filter. The standardization is performed according to JIS K 8006 (basic matters concerning titration during the reagent content test).

(5-2) Operation Weigh correctly 1 to 20 g of sample, add 100 mL of solvent and a few drops of phenolphthalein solution as an indicator, and shake well until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, this is titrated with an N / 10 potassium hydroxide ethyl alcohol solution, and the end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds.

  (5-3) Calculation formula The acid value is calculated by the following formula.

Here, A: acid value B: N / 10 amount of potassium hydroxide ethyl alcohol solution used (mL)
f: Factor of N / 10 potassium hydroxide ethyl alcohol solution S: Sample (g)

(6) Method for measuring saponification value The saponification value is determined as follows. Basic operation conforms to JIS-K0070. The number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids and the like contained in 1 g of a sample is called a saponification value, and the test is conducted as follows.

(6-1) Reagent (a) Solvent Ethyl ether-ethyl alcohol mixed solution (1 + 1 or 2 + 1) or benzene-ethyl alcohol mixed solution (1 + 1 or 2 + 1), these solutions are N / 10 with phenolphthalein as an indicator just before use. Neutralize with potassium hydroxide ethyl alcohol solution.

(B) Phenolphthalein solution 1 g of phenolphthalein is dissolved in 100 mL of ethyl alcohol (95 v / v%).

(C) N / 10 potassium hydroxide-ethyl alcohol solution Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 v / v%) to 1 L, leave it for 2 to 3 days, and filter. The standardization is performed according to JIS K 8006 (basic matters concerning titration during the reagent content test).

(6-2) Operation Weigh correctly 1 to 20 g of sample, add 100 mL of solvent and a few drops of phenolphthalein solution as an indicator, and shake well until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, an excess amount of N / 10 potassium hydroxide-ethyl alcohol solution (100-200 mL) is added thereto, and the mixture is heated to reflux for 1 hour to saponify and then cooled. The obtained solution is back titrated with a N / 10 hydrochloric acid aqueous solution, and the end point of neutralization is taken when the indicator's slight red color disappears continuously for 30 seconds. A blank test is performed in parallel with the main test.

(6-3) Calculation Formula The saponification value is calculated by the following formula.
A = {(B) − (C)} × 5.611 × f / S
Here, A: Saponification value B: Amount of N / 10 hydrochloric acid aqueous solution in the blank test (mL)
C: Amount of N / 10 hydrochloric acid aqueous solution added in this test (mL)
f: Factor of N / 10 hydrochloric acid aqueous solution S: Sample (g)

(7) Measuring method of toner softening point The maximum endothermic peak temperature of the wax component is measured according to “ASTM D 3418-8”. For the measurement, for example, DSC-7 manufactured by PerkinElmer is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. An aluminum pan is used as a measurement sample, an empty pan is set as a control, and measurement is performed at a heating rate of 10 ° C./min.

(8) Method for measuring the hydrophobicity index of black pigment particles Transfer 100 g of xylene, 100 g of water and 0.20 g of black pigment particles to a separatory funnel, shake well, let stand for 10 minutes, and then separate the aqueous layer. The transmittance T of the water layer at a wavelength of 500 nm of incident light is measured. The transmittance of the water at the wavelength 500nm of the incident light is T _0, define the T-T ₀ as hydrophobic index. Using this hydrophobicity index, the degree of hydrophobicity of the black pigment particle surface is determined. For example, the measurement can be performed using a Shimadzu spectrophotometer UV2200 (manufactured by Shimadzu Corporation) and a quartz cell having an optical path length of 1 cm.

(9) Method for Measuring Magnetic Properties of Black Toner and Black Pigment Particles Samples for measurement are prepared in a state of being packed densely in a cylindrical plastic container. The magnetization value (Mt) of the black toner and the magnetization value (Mp) of the black pigment at an external magnetic field of 5000 oersted (398 kA / m) are measured. Then, each 5000 Oersted is returned to 0 Oersted, and the residual magnetization values of the black toner and the black pigment are measured.

  Specifically, it can be measured using, for example, an oscillating magnetic field type magnetic property automatic recording apparatus BHV-30 manufactured by Riken Denshi Co., Ltd. The true density of the black toner and the black pigment can be measured by, for example, a dry automatic densitometer AccuPick 1330 (manufactured by Shimadzu Corporation).

  EXAMPLES Hereinafter, although a manufacture example and an Example demonstrate this invention concretely, these do not limit this invention at all.

<Production Example 1 of Black Pigment Particles>
100 parts by mass of octahedral magnetite (weight average particle diameter (D4p) 0.074 μm, BET specific surface area 18.1 m ² / g, saturation magnetization 85 Am ² / kg)
In a mixture of 1000 parts by weight of water,
A mixture consisting of 80 parts by weight of titanyl sulfate and 500 parts by weight of water was added. Thereafter, the pH of the mixture was adjusted to 8.0, washed and dried to obtain powder 1.

Powder 1 100 parts by mass Sodium sulfate 2 parts by mass The mixture was heated and calcined at 800 ° C. for 60 minutes in a nitrogen atmosphere to obtain calcined pigment 1.

The calcined pigment 1 100 parts by mass Silane coupling agent [n-C ₆ H ₁₃ Si (OCH ₃ ) ₃ ] 0.6 part by mass Water 1000 parts by mass The pH of the above mixture was adjusted to 6 and sufficiently stirred. The generated black pigment particles were washed and dried to obtain black pigment particles 1. The physical properties of the obtained black pigment particles 1 are shown in Table 2.

<Production Examples 2 to 4 of black pigment particles>
Black pigment particles 2 to 4 were obtained in the same manner as in Production Example 1 of black pigment particles except that the type of magnetite and the amount of titanyl sulfate added were the conditions shown in Table 1. Table 2 shows the physical property values of the obtained black pigment particles.

<Production Example 5 of Black Pigment Particles>
The calcined pigment 1 obtained in Production Example 1 of black pigment particles was designated as black pigment particles 5. Table 2 shows the physical property values of the black pigment particles 5.

<Production Example 6 of Black Pigment Particles>
100 parts by mass of spherical magnetite (number average particle size 0.281 μm, BET specific surface area 8.2 m ² / g, saturation magnetization 89 Am ² / kg)
In a mixture of 1000 parts by weight of water,
A mixture consisting of 25 parts by weight of titanyl sulfate and 500 parts by weight of water was added. Thereafter, the pH of the mixture was adjusted to 8.0, washed and dried to obtain powder 6.

Powder 6 100 parts by mass Sodium sulfate 2 parts by mass The mixture was heated and calcined at 800 ° C. for 60 minutes in a nitrogen atmosphere to obtain calcined pigment 6.

The calcined pigment 6 100 parts by mass Silane coupling agent [n-C ₆ H ₁₃ Si (OCH ₃ ) ₃ ] 0.6 parts by mass Water 1000 parts by mass The above mixture was adjusted to pH 8 and sufficiently stirred. The generated black pigment particles were washed and dried to obtain black pigment particles 6. Table 2 shows the physical properties of the black pigment particles 6 thus obtained.

<Black Pigment Particle Production Example 7>
Black pigment particles 7 were obtained in the same manner as in Black Pigment Particle Production Example 6 except that the octahedral magnetite used in Production Example 1 for black pigment particles was changed. Table 2 shows the physical properties of the obtained black pigment particles 7.

<Production Example 8 of Black Pigment Particles>
As shown in Tables 1 and 2,
100 parts by mass of spherical magnetite (number average particle size 0.065 μm, BET specific surface area 18.4 m ² / g, saturation magnetization 85 A m ² / kg)
Was black pigment particles 8.

[Example 1]
After adding 451 parts by mass of 0.1 mol / L Na ₃ PO ₄ aqueous solution to 709 parts by mass of ion-exchanged water and heating to 60 ° C., 67.7 parts by mass of 1.0 mol / L CaCl ₂ aqueous solution was gradually added. An aqueous medium containing Ca ₃ (PO ₄ ) ₂ was obtained.

On the other hand, the following formulation was uniformly dispersed and mixed using an attritor.
-78 parts by mass of styrene-22 parts by mass of n-butyl acrylate-5 parts by mass of saturated polyester resin (acid number 8, Mp12,000)-2 parts by mass of negative charge control agent (Al compound of di-tert-butylsalicylic acid) Black pigment particles (1) 25 parts by mass / polar compound (1) (styrene-maleic anhydride copolymer) [saponification number: 150, peak molecular weight (Mp): 3000]
1.0 part by weight

  This monomer composition was heated to 60 ° C., 15 parts by mass of behenyl behenate was mixed and dissolved therein, and 4 parts by mass of a polymerization initiator tert-butyl peroxide was dissolved therein to prepare a polymerizable monomer system. Obtained.

The polymerizable monomer system was put into the aqueous medium, and the mixture was granulated by stirring at 10,000 rpm for 15 minutes with a homomixer in an N ₂ atmosphere at 60 ° C. Thereafter, the mixture was reacted at 80 ° C. for 1 hour while stirring with a paddle stirring blade. Thereafter, the liquid temperature was raised to 80 ° C., and stirring was further continued for 10 hours. After completion of the reaction, the suspension was cooled, hydrochloric acid was added to dissolve Ca ₃ (PO ₄ ) ₂ , filtered, washed with water, and dried. Subsequently, classification was performed by a multi-division classifier using the Coanda effect, whereby black toner particles 1 were obtained.

  To 100 parts by weight of black toner particles 1, 1.5 parts by weight of silica fine powder having a number average particle size of 130 nm and 0.7 parts by weight of silica fine powder having a number average particle diameter of 40 nm are added and mixed as external additives. Black toner 1 was prepared.

  The physical properties of the obtained black toner 1 are shown in Tables 3 and 4.

  The obtained black toner 1 is filled in a black toner process cartridge of a commercially available color laser beam printer “LBP-2040” (manufactured by Canon Inc.), in a normal temperature and normal humidity environment (23 ° C., 65%), in a low temperature and low humidity environment. Printing was performed in a high-temperature and high-humidity environment (30 ° C., 80% RH) (10 ° C., 15% RH), and evaluation was performed according to the following evaluation criteria. The evaluation results are shown in Table 6.

(Image color gamut)
A solid image formed with a toner amount of 0.8 mg / cm ² is formed on plain paper (color laser copier paper TKCLA4; manufactured by Canon), and the obtained image is obtained using SpectroScan Transmission (manufactured by GretagMacbeth). L * and c * (saturation) of the toner were measured, and the covering power of the toner and the color of the image were evaluated. The evaluation criteria are as follows.
[Toner covering power for solid images]
A: L * is less than 15 Very good covering power.
B: L * is 15 or more and less than 20 Good covering power.
C: Covering power with L * of 20 or more and less than 25 having no practical problem.
D: L * is 25 or more The covering power is inferior.

(Fixability)
Fixability test A fixing unit removed from a commercially available full-color laser beam printer (LBP-2040, manufactured by Canon) was remodeled so that the fixing temperature could be adjusted, and a fixing test of an unfixed image was performed using this. Under normal temperature and humidity, the process speed was set to 180 mm / s, and the toner image was fixed at each temperature while changing the set temperature every 5 ° C. within the range of 110 ° C. to 220 ° C. The temperature at which the low temperature offset is no longer observed is the starting point on the low temperature side of the offset resistance, and the temperature is 5 ° C. lower than the temperature at which the high temperature offset is visually observed or the temperature at which the image receiving paper is wrapped around the fixing device. Was the end point on the high temperature side.

-Measurement method of maximum gloss (glossiness) The gloss value of the fixed image (both the light projection angle and the light reception angle) was measured with a gloss meter. Among the image samples fixed at the respective temperatures, the gloss value with the maximum gloss value is defined as the maximum gloss. For example, it can be measured by micro-TRI-gloss manufactured by BYK-Gardner.

(Dot reproducibility)
Normal paper (color laser copier paper TKCLA4; Canon) in each environment of high temperature and high humidity (30 ° C., 80% Rh), normal temperature and normal humidity (23 ° C., 65% Rh), and low temperature and low humidity (8 ° C., 15% Rh) 1), an image-drawing test was performed using a checker pattern of 80 μm × 50 μm shown in FIG. 1, and the presence or absence of a black part was observed with a microscope, and evaluated according to the following criteria.
A: 2 or less defects in 100 B: 3 to 5 defects in 100 C: 6 to 10 defects in 100 D: 11 or more defects in 100

(Transferability)
About the solid image, the transfer residual toner on the photoconductor after transfer is taped off with Mylar tape, and the tape is attached to plain paper (color laser copier paper TKCLA4; manufactured by Canon), and the image density of the tape is adjusted. By measuring using a “GretagMacbeth reflection densitometer” (manufactured by GretagMacbeth), toner transfer properties at the initial printing stage and after printing 500 sheets were evaluated. The evaluation criteria are as follows.
A: Image density of tape is less than 0.01 Very good transferability.
B: The image density of the tape is 0.01 or more and less than 0.03. Good transferability.
C: The image density of the tape is 0.03 or more and less than 0.10.
D: The image density of the tape is 0.10 or more. Transferability is inferior.

  Table 5 shows the evaluation results for the image color gamut, fine line reproducibility, and transferability.

[Examples 2 to 9, Comparative Examples 1 to 3]
Black toners 2 to 10 were obtained in the same manner as in Example 1 except that the materials and addition amounts used in Example 1 were changed to the formulations shown in Table 2. Tables 3 and 4 show the physical properties of the obtained black toner.

  The same evaluation as in Example 1 was performed using black toners 2 to 10. The evaluation results are shown in Table 5.

Example 8
Pentaerythritol tetrabehenate 300 parts by weight Sodium dodecylbenzenesulfonate 12 parts by weight A mixture of 800 parts by weight of ion-exchanged water was emulsified by high-pressure shearing at 90 ° C. to prepare a wax dispersion 1 having an average particle size of 310 nm. .

Paraffin wax (melting point: 85 ° C.) 300 parts by weight Sodium dodecylbenzenesulfonate 12 parts by weight A mixture of 800 parts by weight of ion-exchanged water is emulsified by high-pressure shearing at 90 ° C. to prepare a wax dispersion 2 having an average particle size of 320 nm. did.

Wax dispersion 1 30 parts by weight Wax dispersion 2 10 parts by weight Sodium dodecylbenzenesulfonate 0.05 part by weight A mixture consisting of 100 parts by weight of ion-exchanged water was heated to 90 ° C,
0.4% by weight of 8% aqueous hydrogen peroxide solution A mixture of 0.4 part by weight of 8% aqueous ascorbic acid solution was added. to this,
Styrene 86.4 parts by weight n-butyl acrylate 18.4 parts by weight Acrylic acid 2.9 parts by weight Octanethiol 0.1 parts by weight Hexanediol diacrylate 0.2 parts by weight
8% hydrogen peroxide aqueous solution 2 parts by weight 8% ascorbic acid aqueous solution 2 parts by weight Sodium dodecylbenzenesulfonate 0.03 part by weight A mixture of 10 parts by weight of ion-exchanged water was added separately over 6 hours. Resin particle dispersion 1 was prepared by time polymerization.

Sodium dodecylbenzenesulfonate 0.05 parts by weight ion exchange water 100 parts by weight is heated to 90 ° C.,
0.4% by weight of 8% aqueous hydrogen peroxide solution A mixture of 0.4 part by weight of 8% aqueous ascorbic acid solution was added. to this,
Styrene 86.3 parts by mass n-butyl acrylate 11.8 parts by mass Acrylic acid 2 parts by mass 2-mercaptoethanol 0.005 parts by mass Hexanediol diacrylate 0.1 parts by mass,
8% hydrogen peroxide aqueous solution 2 parts by weight 8% ascorbic acid aqueous solution 2 parts by weight Sodium dodecylbenzenesulfonate 0.03 part by weight A mixture of 10 parts by weight of ion-exchanged water was added separately over 6 hours. Resin particle dispersion 2 was prepared by time polymerization.

4,4′-methylenebis [2- {N- (4-chlorophenyl) amide} -3-hydroxysinaphthalene] 5 parts by mass Alkylnaphthalene sulfonate 1 part by mass Ion-exchanged water 20 parts by mass (Mitsui Metals Co., Ltd.) was used for dispersion for 3 hours to prepare a charge control agent dispersion.

Black pigment particles 5 50 parts by mass Alkyl naphthalene sulfonate 10 parts by mass A mixture of 200 parts by mass of ion-exchanged water was dispersed for 3 hours using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.) to prepare a black pigment dispersion.

Resin particle dispersion 1 90 parts by weight Resin particle dispersion 2 4 parts by weight While stirring a mixture of 2 parts by weight of charge control agent dispersion,
30 parts by mass of a 2% aqueous aluminum sulfate solution was added dropwise over 1 hour. The temperature was raised to 58 ° C., and 14 parts by mass of resin particle dispersion 2 30 parts by mass of black pigment dispersion 2 parts by mass of charge control agent dispersion were added thereto. further,
40 parts by mass of a 5% aqueous solution of sodium dodecylbenzenesulfonate was added, the temperature was raised to 95 ° C., and maintained for 3 hours to prepare a toner particle dispersion.

  The toner particle dispersion was cooled to 25 ° C., washed and dried to obtain black toner particles. A black toner 8 was produced in the same manner as in Example 1, and the same evaluation was performed. The evaluation results are shown in Table 5.

Example 9
Bisphenol A ethylene oxide 2-mole adduct 334 parts by mass Bisphenol A propylene oxide 2-mole adduct 334 parts by mass Isophthalic acid 230 parts by mass Terephthalic acid 46 parts by mass Dibutyltin oxide 1.5 parts by mass reacted at 230 ° C. for 6 hours And reacted for 4 hours under a reduced pressure of 10 to 15 mmHg. After cooling to 160 and adding 16 parts by mass of phthalic anhydride to this, the mixture was allowed to react for 2 hours, then cooled to 80 ° C., added with a mixture of 1000 parts by mass of ethyl acetate and 77 parts by mass of isophorone diisocyanate, and reacted for 2 hours. 1 was obtained.

A mixture of 220 parts by mass of polyester 1 and 5 parts by mass of isophoronediamine was reacted at 50 ° C. for 2 hours to obtain polyester 2.

Bisphenol A ethylene oxide 2-mole adduct 724 parts by weight Isophthalic acid 230 parts by weight Terephthalic acid 46 parts by weight Dibutyltin oxide 1.5 parts by weight is reacted at 230 ° C. for 6 hours, and reacted under reduced pressure of 10 to 15 mmHg for 4 hours. Polyester 3 was obtained.

Polyester 2 30 parts by weight Polyester 3 50 parts by weight Methyl ethyl ketone 80 parts by weight Ethyl acetate 80 parts by weight Paraffin wax (melting point 85 ° C.) 10 parts by weight Black pigment particles 1 25 parts by weight Charge control agent (aluminum compound of ditertiary butylsalicylic acid) 2 parts by weight The mixture consisting of parts was dispersed for 3 hours using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.) to prepare a dispersion.

In a 2 liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 350 parts by mass of ion-exchanged water and 225 parts by mass of a 0.1 mol / liter-Na ₃ PO ₄ aqueous solution were added. Was adjusted to 12000 rpm and heated to 65 ° C. To this, 34 parts by mass of 1.0 mol / liter-CaCl ₂ aqueous solution was gradually added to prepare an aqueous dispersion medium containing a minute hardly water-soluble dispersant Ca ₃ (PO ₄ ) ₂ .

-272 parts by weight of the above dispersion was charged, and granulated for 15 minutes at 65 ° C with stirring while maintaining a rotational speed of 12000 rpm. Thereafter, the high-speed stirring device was changed to a normal propeller stirring device, the rotation speed of the stirring device was maintained at 150 rpm, the internal temperature was raised to 95 ° C. and held for 3 hours to prepare a toner particle dispersion.

  The toner particle dispersion was cooled to 25 ° C. Dilute hydrochloric acid was added to the aqueous dispersion medium to dissolve the hardly water-soluble dispersant. Further, washing and drying were performed to obtain black toner particles. A black toner 9 was produced in the same manner as in Example 1, and the same evaluation was performed. The evaluation results are shown in Table 5.

It is explanatory drawing of the checker pattern used for dot reproducibility evaluation.

Claims (7)

And at least a binder resin, a black toner having black toner particles containing a black pigment particles having a Na-Fe-Ti compound and Fe ₂ O ₃ -FeTiO ₃ solid solution,
In the black toner particles, in cross-sectional observation of the black toner particles using a transmission electron microscope (TEM), 70% by number or more of the black pigment particles contained in the individual toner particles are from the surface of the black toner particles. A black toner comprising 40 to 100% by number of toner particles satisfying a structure existing up to a depth 0.2 times the projected area equivalent diameter.   The black toner has a molecular weight peak (Mp) of 6,000 to 60,000 in a molecular weight distribution by gel permeation chromatography (GPC) soluble in tetrahydrofuran (THF), and the black toner is obtained by a flow tester. The black toner according to claim 1, which has a softening point of 70 to 120 ° C.   The black toner according to claim 1, wherein the black toner has a hydrophobicity index of 75 to 100. 4.   The black toner according to any one of claims 1 to 3, wherein the black toner contains the black pigment particles in an amount of 8 to 60% by mass based on the total amount of the black toner.   The black toner according to claim 1, wherein the black toner has a Na atom content of 0.10 to 3.00 atomic% with respect to Fe atoms. The black toner is the X-ray diffraction analysis, any of claims 1 to 5 peak intensity ratio of Na-Fe-Ti compound to the peak intensity of Fe ₂ O ₃ -FeTiO ₃ solid solution is 0.01 to 0.45 Black toner according to crab. The black toner according to any one of claims 1 to 6, wherein the black toner has an acid value of 0.1 to 50.0 mgKOH / g in a THF-soluble component contained in the black toner.

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