JP2015225318A - Magnetic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic toner that can provide stable, high-quality images irrespective of a use environment, and has excellent durability particularly under a high-temperature and high-humidity environment.SOLUTION: There is provided a magnetic toner containing magnetic toner particles containing a binder resin and magnetic material and inorganic fine particles, where the thermal conductivity of the magnetic toner is 0.230 W/(m K) or more and 0.270 W/(m K) or less; the inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of a primary particle of 30nm or more and 200nm or less; the magnetic toner contains the silica fine particles in an amount of 0.1 parts by mass or more and 3.0 parts by mass or less relative to 100 parts by mass of the magnetic toner particles; a ratio of the total energy(mJ) of the magnetic toner to the true density(g/ml) of the magnetic toner, which are measured by a powder fluidity measurement apparatus, is 200 mJ/(g/ml) or more and 400 mJ/(g/ml) or less.

Description

  The present invention relates to a magnetic toner used in electrophotography, electrostatic recording, magnetic recording, and the like.

  In recent years, image forming apparatuses such as copiers and printers have been required to have higher speed, higher image quality, and higher stability as the purpose of use and environment of use have diversified. At the same time, in copiers and printers, miniaturization and energy saving of the apparatus are progressing, and a magnetic one-component developing system using magnetic toner which is advantageous in these respects is preferably used.

  In electrophotography, an electrostatic latent image carrier (hereinafter also referred to as a photoreceptor or a drum) is charged by a charging means, and the electrostatic latent image carrier is exposed to form an electrostatic latent image. An exposure process is performed, and a development process is performed in which the electrostatic latent image is developed with toner to form a toner image. Next, a transfer step for transferring the toner image to the recording material with or without the intermediate transfer member, and a nip portion formed by the pressure member and the rotatable image heating member for the recording material carrying the toner image. The image is output as an image through a fixing step of fixing by heating and pressurizing by passing.

  In particular, in the magnetic one-component development system, magnetic toner is held using a toner carrier (hereinafter also referred to as a sleeve) provided with a magnetic field generating means such as a magnet roll, and conveyed to the development area for development.

  In order to cope with the recent increase in image quality, optimization of each process is important. Among them, particularly for image quality, a development process in which an electrostatic latent image is conventionally developed with toner to form a toner image. It is important to do.

  In recent years, printers are often used all over the world, and it is more important to obtain stable images even in various environments. Considering the toner in particular, in a high temperature environment, the toner is easily deteriorated due to ambient heat. However, it has become increasingly important in recent years to ensure durability even in such an environment.

  With respect to such improvement in developability stability, Patent Documents 1 to 4 focus on the dispersibility of the magnetic material and study on improvement in developability. However, in any case, there remains a problem with respect to durability in a high-temperature harsh environment.

JP 2012-47771 A Japanese Patent No. 4854816 Japanese Patent No. 3450686 JP 2013-156616 A

  An object of the present invention is to provide a magnetic toner capable of solving the above problems. Specifically, an object of the present invention is to provide a magnetic toner capable of obtaining a stable and high-quality image regardless of the use environment, and capable of suppressing deterioration of durability particularly in a high-temperature and high-humidity environment.

  The present inventors have found that the problem can be solved by controlling the thermal conductivity of the toner, the particle size and addition amount of inorganic fine particles contained in the toner, and the fluidity, and completed the present invention. It came.

That is, the present invention is a magnetic toner containing a magnetic toner particle containing a binder resin and a magnetic material, and inorganic fine particles,
The magnetic toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
The inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of primary particles of 30 nm to 200 nm,
The magnetic toner contains 0.1 to 3.0 parts by mass of the silica fine particles with respect to 100 parts by mass of the magnetic toner particles;
The ratio of the total energy (mJ) of the magnetic toner and the true density (g / ml) of the magnetic toner, measured by a powder flowability measuring device, is 200 mJ / (g / ml). ) And 400 mJ / (g / ml) or less.

  According to the present invention, it is possible to provide a magnetic toner that can stably obtain a high-quality image regardless of the use environment and can suppress deterioration of durability particularly under high temperature and high humidity.

1 is a diagram illustrating an example of an image forming apparatus. It is a schematic diagram which shows the structure of the stirring member used for evaluation of total energy.

The present invention is a magnetic toner containing magnetic toner particles containing a binder resin and a magnetic material, and inorganic fine particles,
The magnetic toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
The inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of primary particles of 30 nm to 200 nm,
The magnetic toner contains 0.1 to 3.0 parts by mass of the silica fine particles with respect to 100 parts by mass of the magnetic toner particles;
The ratio of the total energy (mJ) of the magnetic toner and the true density (g / ml) of the magnetic toner, measured by a powder flowability measuring device, is 200 mJ / (g / ml). ) Or more and 400 mJ / (g / ml) or less.

  According to the study by the present inventors, by using the above toner, it is possible to provide a toner capable of stably obtaining a high-quality image regardless of the use environment, and capable of suppressing durability deterioration particularly in a high temperature severe environment. I found it possible. The present inventors consider the mechanism capable of suppressing the durability deterioration under the high temperature severe environment as follows.

  First, let us consider the mechanism of durability deterioration of the toner, particularly in a high temperature and high humidity environment.

  Under high temperature, the heat energy from the surrounding environment is always supplied to the toner, and the toner is easily deformed. Therefore, it depends on the durability of inorganic fine particles (hereinafter also referred to as external additives) present on the toner particle surface. It becomes a state where burial is also easily promoted. Further, during durability evaluation for outputting a large amount of images, the toner is rubbed with the members in the cartridge and the toners, and is likely to be deteriorated. Therefore, in order to suppress durability deterioration, it is important not to accumulate heat as much as possible in the toner even during durability.

  As a result of intensive studies, the present inventors have derived the direction of improvement from the behavior of the toner in such a cartridge, found a configuration in which heat does not accumulate in the toner, and have reached the present invention.

  In other words, it is possible to increase the heat conductivity of the toner, and further, by controlling the particle size of the silica fine particles existing on the toner surface within a predetermined particle size range and controlling the fluidity, it is possible to promote heat dissipation from the toner. Thus, the present inventors have found that it is effective for suppressing durability deterioration under a high temperature and high humidity environment.

That is, a magnetic toner containing magnetic toner particles containing a binder resin and a magnetic material, and inorganic fine particles,
The magnetic toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
The inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of primary particles of 30 nm to 200 nm,
The magnetic toner contains 0.1 to 3.0 parts by mass of the silica fine particles with respect to 100 parts by mass of the magnetic toner particles;
The ratio of the total energy (mJ) of the magnetic toner and the true density (g / ml) of the magnetic toner, measured by a powder flowability measuring device, is 200 mJ / (g / ml). It is important that it is 400 mJ / (g / ml) or less.

  The thermal conductivity of the toner is considered to represent the ease with which heat applied to the toner is transmitted. The present inventors considered that the heat accumulated in the toner can be radiated to the outside by controlling the physical properties. As a result of intensive studies, if the thermal conductivity of the toner is less than 0.230 W / (m · K), the heat dissipation effect is small and durability deterioration cannot be suppressed. It has been found that the thermal conductivity of the toner is not preferable because fusion is likely to occur at the end of the fixing unit that is severe in temperature rise.

  It was also found that controlling the dispersibility of the magnetic material is important for controlling the thermal conductivity of the toner. This is considered to indicate that the presence of a metal powder such as a magnetic material having high heat conductivity greatly contributes to improving the thermal conductivity between toners.

  Further, by controlling the particle size and amount of the silica fine particles existing on the toner surface within a predetermined range, it is possible to make silica fine particles having a certain particle size between the toners, and the toners directly rub against each other. (Hereinafter also referred to as the spacer effect), heat release from the toner is promoted. As a result, when the toners are in close contact with each other, the heat accumulated in the toners is exchanged between the toners, and it is difficult to dissipate the heat to the outside of the toners. Therefore, it is estimated that the heat dissipation effect of the heat in the toner to the outside of the toner is enhanced.

  In addition, when the inorganic fine particles are silica fine particles having a primary particle number average particle size (D1) of less than 30 nm, a sufficient spacer effect cannot be obtained, and in the case of silica fine particles of more than 200 nm, the fluidity is reduced. Since desired durability cannot be obtained, it is not preferable.

  In addition, when the content of the silica fine particles is less than 0.1 parts by mass, the desired spacer effect cannot be obtained, which is not preferable. When the content is more than 3.0 parts by mass, the heat dissipation effect is obtained by reducing the fluidity. This is not preferable because the desired durability deterioration suppressing effect cannot be obtained.

  Furthermore, in the present invention, the fluidity of the toner in the toner cartridge is ensured by controlling the fluidity of the toner. As a result, compared with the case where fluidity is insufficient, the heat dissipation effect is further promoted, and the durability deterioration suppressing effect is further enhanced.

  In the present invention, [total energy amount (mJ) / toner density (g / ml)] (hereinafter also referred to as TE / density) measured by a powder fluidity measuring device equipped with a rotary propeller blade of a magnetic toner. Is an index indicating the fluidity of the toner. This is considered to be an index indicating the fluidity of the toner in the cartridge. If the TE / density is less than 200 mJ / (g / ml), the fluidity of the toner is too high and a sufficient charge amount may not be obtained. On the other hand, if it exceeds 400 mJ / (g / ml), the fluidity of the toner is relatively low, so that the flow in the cartridge is insufficient, and the toner may easily deteriorate in durability.

  When the fluidity of the toner is ensured, compared with the case where the fluidity of the toner is low, it is easy to dissipate the heat in the toner while the toner flows in the cartridge, so that deterioration in durability can be suppressed.

  As described above, in the present invention, by simultaneously controlling the thermal conductivity of the magnetic toner, the particle size and amount of the silica fine particles contained in the toner, and the fluidity, the effect of suppressing durability deterioration under a desired high temperature and high humidity. Was found to be obtained.

  Further, as described above, the control of the dispersibility of the magnetic material is important for the control of the thermal conductivity.

In the present invention, it is preferable that the dielectric loss tangent tan δ, which is one of the indicators of magnetic substance dispersibility, is 1.0 × 10 ⁻² or more and 2.0 × 10 ⁻² or less.

  The dielectric loss tangent tan δ is related to the cohesiveness and dispersibility of the magnetic substance in the toner and between the toners, and the smaller the value, the closer to the uniform dispersion within and between the particles. On the other hand, in the present invention, although the dispersed state of the magnetic material is a uniform state between the particles, considering the single toner particle, it is dispersed near the surface to increase the thermal conductivity.

As a result of the study by the present inventors, the dielectric loss tangent tan δ is 1.0 × 10 ⁻² or more and 2.0 × 10 ⁻² or less, so that the dispersibility of the magnetic substance between particles is good and It is preferable because it is present in the vicinity of the surface and developability, in particular, fog and thermal conductivity are improved.

  In the present invention, the average circularity of the toner is preferably 0.960 or more, more preferably 0.970 or more, and further preferably 0.980 or more. It is preferable that the average circularity is 0.960 or more because the fluidity of the toner is improved and the durability deterioration can be further improved.

  The magnetic material used in the toner of the present invention is preferably a treated magnetic material obtained by surface-treating magnetic iron oxide with a silane compound. This is because it is necessary to hydrophobize the magnetic material during the production by the suspension polymerization method preferably used for controlling the dispersibility of the magnetic material. As a result of intensive studies on the dispersibility of the magnetic material, it has been found that it is preferable to treat with a silane compound. Specifically, in the suspension polymerization method, a monomer composition containing a magnetic material is dispersed in an aqueous medium, granulated, and a polymerizable monomer contained in the granulated particles is polymerized. Therefore, the surface of the magnetic material to be used needs to be hydrophobized so as not to be exposed to the aqueous system. This is because normally untreated magnetic iron oxide has high hydrophilicity because functional groups such as hydroxyl groups exist on the surface.

  Here, silane compounds, titanate compounds, aluminate compounds, and the like are generally known as surface treatment agents, but these surface treatment agents all hydrolyze and undergo a condensation reaction with hydroxyl groups on the surface of magnetic iron oxide. It has a strong chemical bond and exhibits hydrophobicity. However, it is known that these hydrolyzed compounds undergo self-condensation and are liable to form polymers and oligomers. As a result of intensive studies by the present inventors, titanate compounds and aluminate compounds are susceptible to self-condensation after hydrolysis, and it is difficult to uniformly treat the magnetic iron oxide surface. This is considered to be because the activity of titanium and aluminum contained in the titanate compound and the aluminate compound is high. On the other hand, the silane compound can suppress the self-condensation while increasing the hydrolysis rate by controlling the hydrolysis conditions, and can uniformly treat the magnetic iron oxide surface. The present inventors consider that this is because the silicon activity of the silane compound is not as high as that of titanium or aluminum. For this reason, it is preferable to use a silane compound.

  Further, the magnetic iron oxide used in the present invention has silicon element on the surface, and silicon that is eluted when the magnetic iron oxide is dissolved until the dissolution rate of the iron element reaches 5.00% by mass. Is preferably 0.05% by mass or more and 0.50% by mass or less based on the magnetic iron oxide. This is considered because the affinity between the magnetic iron oxide surface and the silane compound is improved, and the uniformity of the treatment with the silane compound is further improved. Further, the affinity between the magnetic iron oxide surface and the silane compound is improved, so that the amount of the silane compound bonded to the magnetic iron oxide surface is increased.

  For the above reasons, in the present invention, it is important that a specific amount of silicon element is present on the surface of magnetic iron oxide and in the vicinity thereof. Specifically, the magnetic iron oxide is dispersed in an aqueous hydrochloric acid solution, and the magnetic iron oxide is dissolved until the dissolution rate of the iron element is 5.00% by mass with respect to the total iron element amount contained in the magnetic iron oxide. It is important that the amount of silicon eluted up to that point is 0.05% by mass or more and 0.50% by mass or less with respect to the magnetic iron oxide.

  Here, regarding the dissolution rate of the iron element of the magnetic iron oxide, the dissolution rate of the iron element is 100% by mass, which is a state in which the magnetic iron oxide is completely dissolved. It means that the whole iron oxide has melted. As a result of intensive studies by the present inventors, magnetic iron oxide is uniformly dissolved from the surface under acidic conditions.

  Therefore, it is considered that the amount of the element eluted before the iron element dissolution rate reaches 5.00% by mass indicates the amount of the element present on the magnetic iron oxide surface and its vicinity. When the amount of silicon present on and around the magnetic iron oxide surface is 0.05% by mass or more, as described above, the affinity between the silane compound and the magnetic iron oxide is improved, and the uniformity of processing is improved. . For this reason, the dispersibility of the magnetic substance in the toner can be improved.

  On the other hand, when the amount of silicon present on the surface of the magnetic iron oxide and in the vicinity thereof is more than 0.50% by mass, the environmental stability of the toner tends to be lowered, which is not preferable. The reason for this is as follows.

  The area (covering area) that can be coated with one molecule is determined for the silane compound that surface-treats the magnetic iron oxide surface. For this reason, the maximum amount of the silane compound that can be condensed per unit area is determined by the covering area. For these reasons, when the silicon content is more than 0.50% by mass, silicon and silanol groups derived from the silicon will remain on the surface of the magnetic iron oxide, resulting in a surface that easily adsorbs moisture, It becomes inferior to environmental stability.

  Further, in order to control the surface state of such a magnetic material, it is necessary to control it by assuming a magnetic toner manufacturing process manufactured by the present invention.

  That is, it is necessary to maintain the amount of the silane compound on the surface even in a polymerizable monomer such as styrene. As a result of intensive studies by the present inventors, the amount of residual carbon derived from the silane compound after styrene cleaning is preferably 0.40% by mass or more and 1.20% by mass or less based on magnetic iron oxide. . By washing with styrene, the adhesion amount of the silane compound on the surface of the magnetic material during the production of the magnetic toner produced according to the present invention can be estimated by the amount of residual carbon. In general, the present inventors consider that the hydrocarbon group is important for the silane compound to exhibit hydrophobicity, that is, the amount of carbon is effective in estimating the hydrophobic capacity.

  When the adhesion amount is less than 0.40% by mass, sufficient hydrophobic ability cannot be obtained, and the magnetic material is easily exposed to the aqueous system in the production method of the present invention. In addition, when the adhesion amount exceeds 1.20% by mass, unevenness in the coating property of the processing agent is likely to occur, resulting in a decrease in the uniformity of processing, resulting in unevenness in the state of presence of the magnetic material between the toner particles. The uniformity of the toner particles is inferior and the desired performance cannot be obtained.

  In addition, the silane compound obtained by treating the magnetic material used in the method for producing magnetic toner is preferably obtained by subjecting alkoxysilane to hydrolysis treatment, and the hydrolysis rate of alkoxysilane is preferably 50% or more. In general, silane compounds are used without being hydrolyzed and are often treated as they are. However, in this case, they cannot have a chemical bond with a hydroxyl group or the like on the surface of magnetic iron oxide and have only a physical adhesion strength. No. In this state, the silane compound is likely to be detached due to the share received during toner formation.

  For the reasons described above, in the present invention, the silane compound is preferably one obtained by subjecting alkoxysilane to hydrolysis treatment. By performing the hydrolysis treatment, the silane compound is adsorbed to the hydroxyl group on the surface of the magnetic iron oxide through a hydrogen bond, and a strong chemical bond is formed by heating and dehydrating it. Moreover, by forming a hydrogen bond, volatilization of the silane compound can be suppressed during heating, and it becomes easy to obtain a material that satisfies the regulations regarding the amount of moisture adsorption.

  For these reasons, in the present invention, the hydrolysis rate of the silane compound is preferably 50% or more, more preferably 80% or more, and still more preferably 90% or more. When the hydrolysis rate of the silane compound is 50% or more, the magnetic iron oxide surface can be treated with many treatment agents for the reasons described above. Furthermore, the uniformity of the surface treatment is improved, and the dispersibility of the magnetic material is further improved. For this reason, the uniformity between the toners is increased, and even when the toner is continuously used, for example, in an endurance test, the toner charging is stabilized, and as a result, a stable image can be obtained. The hydrolysis rate of the silane compound is a value obtained by subtracting the ratio of the remaining alkoxy groups with the hydrolysis rate of 100% when the alkoxysilane is completely hydrolyzed.

  Next, the magnetic material used in the method for producing a magnetic toner produced according to the present invention is preferably surface-treated in a gas phase with a silane compound.

  There are two types of methods for surface treatment of magnetic materials, dry and wet. When the surface treatment is performed by a dry method, a silane compound is added to the dried magnetic material, and the surface treatment is performed in a gas phase.

  In the case of wet surface treatment, the dried material is redispersed in an aqueous medium, or after the oxidation reaction, iron oxide is redispersed in another aqueous medium without drying, and the surface treatment with a silane compound is performed. I do. The magnetic material used in the present invention is a magnetic material that has been surface-treated in a gas phase with a silane compound (hereinafter also referred to as a dry method), which improves the dispersibility of the magnetic material between the magnetic toners produced by the present invention. It is preferable to achieve the above. The reason for this is as follows.

  In the dry method, since only a small amount of water is present in the reaction system, it is difficult to form a hydrogen bond between the hydrophilic group contained in the silane compound and water. Therefore, compared with the wet process in which water is present, the hydrogen bonding rate with the surface of the magnetic material is increased, and a more uniform and efficient hydrophobic treatment with a silane compound can be performed. Further, when the hydrophilic group of the treatment agent forms a hydrogen bond with water and adsorbs and reacts with the surface of the magnetic body while trapping water, the hydrophilic group remains on the surface of the treated magnetic body without being reacted. Since hydrophilic groups are easily compatible with water, when there are many magnetic hydrophilic groups, uneven distribution of magnetic substances during toner production tends to occur. Since the dry processing method can prevent such problems due to hydrogen bonding, the uniform coverage of the magnetic silane compound used in the magnetic toner produced by the present invention is improved. As a result, the magnetic material dispersibility can be further improved and the uniform chargeability of the toner can be improved, which is advantageous in terms of fogging, for example.

  Hereinafter, details of a method for producing a magnetic material used for the magnetic toner produced by the production method of the present invention will be described.

  Hydrolysis of the alkoxysilane used in the magnetic material used in the present invention is preferably carried out as follows. Specifically, alkoxysilane is gradually added to an aqueous solution or a mixed solution of alcohol and water whose pH is adjusted to 4.0 or more and 6.5 or less, and uniformly dispersed using, for example, a disper blade. At this time, it is preferable that the liquid temperature of a dispersion liquid is 35 degreeC or more and 60 degrees C or less. Generally, the lower the pH and the higher the liquid temperature, the easier the alkoxysilane is hydrolyzed. As a result of diligent investigations by the present inventors, the use of a dispersing device capable of imparting high shear, such as a disperse blade, even under difficult hydrolysis conditions, increases the contact area of alkoxysilane and water, thereby efficiently adding water. Degradation could be promoted. This makes it possible to suppress self-condensation while increasing the hydrolysis rate. Specifically, alkoxysilane is gradually added to an aqueous solution or a mixed solution of alcohol and water whose pH is adjusted to 4.0 or more and 6.5 or less, and uniformly dispersed using, for example, a disper blade. At this time, it is preferable that the liquid temperature of a dispersion liquid is 35 degreeC or more and 60 degrees C or less. In the present invention, it is preferable to treat the surface of magnetic iron oxide with a silane compound in the gas phase. As described above, the magnetic substance of the present invention can have a strong chemical bond by adsorbing a silane compound on the surface of magnetic iron oxide by hydrogen bonding and dehydrating it. However, since the hydrogen bond between the silane compound and the surface of the magnetic iron oxide is a reversible reaction, it is possible to treat the surface of the magnetic iron oxide with more silane compounds when there is less water in the system. As a result, the hydrophobicity of the treated magnetic material is greatly increased, and the rise of charging of the toner is accelerated. Furthermore, it is preferable because a ghost hardly occurs.

  A known stirring device can be used as a device for surface treatment of magnetic iron oxide. Specifically, a Henschel mixer (Mitsui Miike Chemical), a high speed mixer (Fukae Powtech), a hybridizer (Nara Machinery Co., Ltd.), etc. are preferable.

Magnetic iron oxide is composed mainly of triiron tetroxide or γ-iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, and aluminum. Magnetic material, it is preferable that a BET specific surface area is less than 2.0 m ² / g or more 20.0 m ² / g by a nitrogen adsorption method, not more than 3.0 m ² / g or more 10.0 m ² / g More preferred. The shape of the magnetic body includes a polyhedron, an octahedron, a hexahedron, a sphere, a needle, and a scale, but a polyhedron, an octahedron, a hexahedron, a sphere, and the like having a low anisotropy increase the image density. Preferred above. The magnetic material preferably has a volume average particle diameter (Dv) of 0.10 μm or more and 0.40 μm or less from the viewpoint of uniform dispersibility and color in the toner. The volume average particle diameter (Dv) of the treated magnetic material can be measured using a transmission electron microscope. Specifically, after sufficiently dispersing the toner particles to be observed in the epoxy resin, a cured product obtained by curing in an atmosphere at a temperature of 40 ° C. for 2 days is obtained. The obtained cured product is used as a flaky sample by a microtome, and the particle diameters of 100 processed magnetic bodies in the field of view are measured with a transmission electron microscope (TEM) at a magnification of 10,000 to 40,000 times. . Then, the volume average particle diameter (Dv) is calculated based on the equivalent diameter of a circle equal to the projected area of the processed magnetic body. It is also possible to measure the particle size with an image analyzer.

  The treated magnetic material used in the magnetic toner produced according to the present invention can be produced, for example, by the following method. Specifically, an aqueous solution containing ferrous hydroxide is prepared by adding an alkali such as sodium hydroxide in an amount equivalent to or greater than the iron component to the ferrous salt aqueous solution. Air was blown in while maintaining the pH of the prepared aqueous solution at 7.0 or higher, and ferrous hydroxide was oxidized while heating the aqueous solution to 70 ° C. or higher, and seed crystals serving as the core of the magnetic iron oxide particles were formed. First generate. Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. The pH of the liquid is maintained at 5.0 or higher and 10.0 or lower, and the reaction of ferrous hydroxide proceeds while blowing air, and magnetic iron oxide particles are grown with the seed crystal as a core. At this time, it is possible to control the shape and magnetic properties of the magnetic iron oxide by selecting an arbitrary pH, reaction temperature, and stirring conditions. As the oxidation reaction proceeds, the pH of the liquid shifts to the acidic side, but the pH of the liquid is preferably not less than 5.0. After completion of the oxidation reaction, a silicon source such as sodium silicate is added to adjust the pH of the solution to 5.0 or more and 8.0 or less. In this way, a silicon coating layer is formed on the surface of the magnetic iron oxide particles. Magnetic iron oxide particles can be obtained by filtering, washing, and drying the magnetic iron oxide particles obtained as above.

  The amount of silicon element present on the magnetic iron oxide surface can be controlled by adjusting the amount of silicon source such as sodium silicate added after the oxidation reaction is completed.

  Next, surface treatment with a silane compound essential for the present invention is performed. Specifically, the liquid temperature is adjusted so that the aqueous solution whose pH is adjusted to 3.0 or more and 6.5 or less is 35 ° C. or more and 50 ° C. or less. Alkoxysilane is gradually added to this aqueous solution, and it is uniformly stirred and dispersed using, for example, a disper blade, etc., and hydrolysis is performed. The hydrolyzate thus obtained is added to magnetic iron oxide and mixed uniformly with a stirrer / mixer such as a high speed mixer or a Henschel mixer. Thereafter, drying and pulverization can be performed at a temperature of 80 ° C. or higher and 160 ° C. or lower to obtain a surface-treated magnetic body.

  When wet surface treatment is performed, after the oxidation reaction is completed, the dried product is redispersed, or after completion of the oxidation reaction, the iron oxide body obtained by washing and filtering is not dried but in another aqueous medium. And re-disperse to surface treatment. Specifically, the surface treatment is performed by adding alkoxysilane while sufficiently stirring the re-dispersed liquid to increase the temperature after hydrolysis, or adjusting the pH of the dispersion to an alkaline region after hydrolysis.

Examples of the silane compound that can be used for the surface treatment of magnetic iron oxide include those represented by the general formula (1).
RmSiYn (1)
(In the formula, R represents an alkoxy group or a hydroxyl group, m represents an integer of 1 to 3, Y represents an alkyl group or a vinyl group, and the alkyl group includes, as a substituent, an amino group, a hydroxyl group, It may have a functional group such as an epoxy group, an acrylic group, a methacryl group, etc. n represents an integer of 1 to 3, provided that m + n = 4.

  Examples of the silane compound represented by the general formula (1) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4 epoxy cyclohexyl) ethyltrimethoxysilane, γ- Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltri Acetoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiet Sisilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxypropyltrimethoxy Examples thereof include silane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, and hydrolysates thereof.

  When the silane compound is used, it can be treated alone or in combination of a plurality of types. When using several types together, you may process separately with each silane compound, and may process simultaneously.

  In the present invention, the content of the magnetic substance is preferably 20 parts by mass or more and 150 parts by mass or less, and more preferably 50 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the binder resin.

  Note that the content of the magnetic substance in the toner can be measured using a thermal analyzer, TGA7, manufactured by PerkinElmer. The measuring method is as follows. The toner is heated from room temperature to 900 ° C. at a temperature rising rate of 25 ° C./min in a nitrogen atmosphere. The weight loss mass% between 100 ° C. and 750 ° C. is defined as the binder resin amount, and the remaining mass is approximately defined as the treated magnetic material amount.

  The weight average particle size (D4) of the magnetic toner produced according to the present invention is preferably 3.0 μm or more and 12.0 μm or less, more preferably 4.0 μm or more and 10.0 μm or less. When the weight average particle diameter (D4) is 3.0 μm or more and 12.0 μm or less, good fluidity can be obtained and development can be performed faithfully to the latent image.

  The magnetic toner produced according to the present invention preferably has an average circularity of 0.960 or more, and more preferably a mode circularity of 0.97 or more. When the average circularity of the toner is 0.960 or more, the toner has a spherical shape or a shape close to it, and it is easy to obtain a uniform triboelectric chargeability with excellent fluidity. For this reason, it is preferable because high developability is easily maintained even in the latter half of the durability.

  Examples of the binder resin used in the magnetic toner produced by the present invention include styrene such as polystyrene and polyvinyltoluene, and homopolymers thereof, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene- Vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl ether Copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers, and other styrenic copolymers , Polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin can be used. They can be used in combination. Of these, styrene-acrylic resins are particularly preferred from the standpoints of development characteristics and fixing properties.

  The magnetic toner produced according to the present invention may be blended with a charge control agent as necessary to improve the charging characteristics. As the charge control agent, a known one 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 using a polymerization method as described later, a charge control agent having a low polymerization inhibitory property and substantially free of soluble matter in an aqueous dispersion medium is particularly preferable. Among the charge control agents, specific examples of negative charge control agents include metal compounds of aromatic carboxylic acids such as salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, dicarboxylic acid, azo dyes or metal salts of azo pigments or Examples thereof include a metal complex, a polymer compound having a sulfonic acid or carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, and a calixarene. Examples of the positive charge control agent include quaternary ammonium salts, polymer compounds having the quaternary ammonium salt in the side chain, guanidine compounds, nigrosine compounds, imidazole compounds, and the like.

  The amount of these charge control agents used is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. However, when added internally to the toner particles, it is preferably 0.1 parts by weight or more and 10.0 parts by weight or less, more preferably 0.1 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the binder resin. Used in a range. In addition, when externally added to the toner particles, the amount is preferably 0.005 parts by mass or more and 1.000 parts by mass or less, more preferably 0.01 parts by mass or more and 0.30 parts by mass or less with respect to 100 parts by mass of the toner particles. .

  A release agent may be blended with the magnetic toner produced according to the present invention, if necessary, in order to improve fixability. Any known release agent can be used as the release agent. Specifically, paraffin wax, microcrystalline wax, petroleum wax such as petrolatum and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof by Fischer-Tropsch method, polyolefin wax and derivatives thereof typified by polyethylene, Natural waxes such as carnauba wax and candelilla wax and their derivatives, ester waxes and the like. Here, the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. As the ester wax, monofunctional ester wax, bifunctional ester wax, and other polyfunctional ester waxes such as tetrafunctional and hexafunctional can be used.

  In the present invention, it is preferable that the toner contains a release agent of 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin in terms of both durability and fixability.

  The toner produced according to the present invention preferably has a core-shell structure in order to improve storage stability and developability. This is because by having the shell layer, the surface property of the toner becomes uniform, the fluidity improves and the charging property becomes uniform. Further, since the high molecular weight shell uniformly covers the surface layer, the low-melting-point substance does not easily leach out even during long-term storage, and the storage stability is improved. Therefore, it is preferable to use an amorphous polyester resin for the shell layer. In the present invention, from the viewpoint of improving the dispersibility of the magnetic material, the acid value is 0.1 mgKOH / g or more and 5.0 mgKOH / g or less. It is important to be.

  As a specific method for forming the shell, in the suspension polymerization method, the hydrophilicity of the high molecular weight material for the shell is utilized, and the high molecular weight material is unevenly distributed near the interface with water, that is, near the toner surface. It is possible to form. Furthermore, a shell can be formed by swelling a monomer on the surface of the core particle by a so-called seed polymerization method and polymerizing the monomer.

  As the polyester resin used in the present invention, a saturated polyester resin, an unsaturated polyester resin, or both can be appropriately selected and used. As the polyester resin used in the present invention, a normal resin composed of an alcohol component and an acid component can be used, and both components are exemplified below.

  As alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, and bisphenol derivatives represented by formula (I);

［式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２以上１０以下である。］
あるいは式（Ｉ）の化合物の水添物、また、式（ＩＩ）で示されるジオール；

[Wherein, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 or more and 10 or less. ]
Or hydrogenated compound of formula (I), or diol of formula (II);

あるいは式（ＩＩ）の化合物の水添物のジオールが挙げられる。

Or the diol of the hydrogenated compound of the compound of a formula (II) is mentioned.

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

  In addition, polyhydric alcohols such as glycerin, pentaerythritol, sorbit, sorbitan, and oxyalkylene ethers of novolac type phenol resins can be cited as the alcohol component, and trimellitic acid, pyromellitic acid, 1,2,3,4- Examples thereof include polyvalent carboxylic acids such as butanetetracarboxylic acid, benzophenonetetracarboxylic acid and anhydrides thereof.

  Among the polyester resins, the alkylene oxide adduct of bisphenol A, which is excellent in charging characteristics and environmental stability and balanced in other electrophotographic characteristics, is preferably used. In the case of this compound, the average number of added moles of alkylene oxide is preferably 2 or more and 10 or less in terms of fixability and toner durability.

  It is preferable that 45 mol% or more and 55 mol% or less of the above-mentioned polyester resin is an alcohol component, and 55 mol% or more and 45 mol% or less is an acid component.

  When the toner is produced by the suspension polymerization method, the amount of these resins added is preferably 1.0 part by weight or more and 30.0 parts by weight or less in total with respect to 100 parts by weight of the polymerizable monomer. Preferably they are 1.0 mass part or more and 20.0 masses or less.

  The number average molecular weight (Mn) of the high molecular weight body forming the shell is preferably 2500 or more and 20000 or less. A number average molecular weight (Mn) of 2500 or more and 20000 or less is preferable because the developability, blocking resistance, and durability can be improved without impairing the fixability. The number average molecular weight (Mn) can be measured by GPC.

  Next, the suspension polymerization method used in the present invention will be described.

  Suspension polymerization is a method in which a polymerizable monomer and a treated magnetic substance (and a polymerization initiator, a crosslinking agent, a charge control agent, and other additives as necessary) are uniformly dissolved or dispersed to form a polymerizable monomer. A body composition is obtained. Thereafter, this polymerizable monomer composition is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer by using a suitable stirrer, and a polymerization reaction is simultaneously performed to obtain a toner having a desired particle size. To get.

  The strength at the time of stirring contributes to the material dispersibility, and stirring is performed with an appropriate dispersion strength as required for productivity and the like.

  The toner obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner”) is preferable because the shape of individual toner particles is almost spherical, and the charge amount distribution is relatively uniform.

  In the production of the toner by the suspension polymerization method, examples of the polymerizable monomer constituting the polymerizable monomer composition include the following.

  Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, ethyl acrylate, Acrylate esters such as n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate , Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Methacrylic acid dimethyl aminoethyl, methacrylic acid esters such as diethylaminoethyl methacrylate and other acrylonitrile, methacrylonitrile, and the like monomers acrylamide. These monomers can be used alone or in combination. 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.

  As the polymerization initiator used in the production of the magnetic toner produced by the present invention by polymerization, the half-life at the time of the polymerization reaction is 0.5 hours or more and 30.0 hours or less for controlling the meltability of the toner. Some are preferred. Moreover, it is preferable that the addition amount of a polymerization initiator is 0.5 to 20.0 mass parts with respect to 100 mass parts of polymerizable monomers, and is 5.0 to 15.0 mass parts. More preferably, it is 6.0 parts by mass or more and 10 parts by mass or less.

  As the polymerization initiator, known ones can be used, and specifically, azo initiators, peroxide initiators, and the like can be used.

  In the production of the magnetic toner particles of the present invention, a crosslinking agent can be added as necessary. A preferable addition amount is 0.01 parts by mass or more and 10.00 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. Here, as the crosslinking agent, compounds having two or more polymerizable double bonds are mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, such as ethylene glycol diacrylate and ethylene glycol diacrylate. Carboxylic acid ester having two double bonds, such as methacrylate, 1,3-butanediol dimethacrylate, divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, and three or more vinyl groups A compound is used alone or as a mixture of two or more.

  In the method of producing a magnetic toner produced by the present invention by polymerization, generally the above-described toner composition is appropriately added, and the polymer is uniformly dissolved or dispersed by a disperser such as a homogenizer, ball mill, or ultrasonic disperser. The soluble monomer composition is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size all at once. The polymerization initiator may be added at the same time as 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 a normal stirrer to such an extent that the particle state is maintained and the particles are prevented from floating and settling.

  In the production of the magnetic toner produced according to the present invention, known surfactants, organic dispersants and inorganic dispersants can be used as the dispersion stabilizer. Among them, inorganic dispersants are less likely to produce harmful ultrafine powders, and because they have dispersion stability due to their steric hindrance, they are highly stable even when the reaction temperature is changed, are easy to wash, and do not adversely affect the toner. Can be preferably used. Examples of such inorganic dispersants include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, phosphate polyvalent metal salts such as hydroxyapatite, carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate, Examples thereof include inorganic salts such as barium sulfate and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

  These inorganic dispersants are preferably used in an amount of 0.20 parts by mass or more and 20.0 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. Moreover, the said dispersion stabilizer may be used independently and may use multiple types together. Further, in addition to the dispersion stabilizer, a surfactant may be used in combination.

  In the step of polymerizing the polymerizable monomer, the polymerization temperature is set to 40 ° C or higher, and generally 50 ° C to 90 ° C.

  After the polymerization of the polymerizable monomer is completed, the obtained polymer particles are filtered, washed and dried by a known method to obtain toner particles. The magnetic particles produced according to the present invention can be obtained by mixing the toner particles with inorganic fine particles as described later, if necessary, and adhering them to the surface of the toner particles. It is also possible to insert a classification step in the manufacturing process (before mixing of the inorganic fine particles) to cut coarse powder and fine powder contained in the toner particles.

  The magnetic toner produced according to the present invention has inorganic fine particles, and it is important that the inorganic fine particles contain silica fine particles having a number average primary particle size (D1) of 30 nm or more and 200 nm or less. As described above, it is important that the number average primary particle size (D1) of the inorganic fine particles is 30 nm or more and 200 nm or less in order to suppress the durability deterioration under high temperature and high humidity.

  In the present invention, the number average primary particle size (D1) of the inorganic fine particles is measured using a photograph of the toner magnified with a scanning electron microscope.

As the inorganic fine particles used in the present invention, silica, titanium oxide, alumina and the like can be used. Among them, as silica fine particles, for example, both so-called dry method produced by vapor phase oxidation of silicon halide or dry silica called fumed silica and so-called wet silica produced from water glass can be used. It is. However, dry silica having fewer silanol groups on the surface and inside the silica fine particles and less production residue such as Na ₂ O and SO ₃ ²⁻ is more preferable. In dry silica, it is also possible to obtain composite fine particles of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  In the present invention, it is important that the amount of the inorganic fine particles added is from 0.1 parts by weight to 3.0 parts by weight with respect to 100 parts by weight of the magnetic toner particles. It is important for the amount of inorganic fine particles added to be in the above-mentioned range since there is no adverse effect on the fixability and developability and a desired spacer effect can be obtained.

  There is no problem in using inorganic fine particles having a number average primary particle size (D1) of less than 30 nm in combination.

  The content of inorganic fine particles can be quantified using a calibration curve prepared from a standard sample using fluorescent X-ray analysis.

  Next, an example of an image forming apparatus that can suitably use the toner of the present invention will be specifically described with reference to FIG. In FIG. 1, reference numeral 100 denotes an electrostatic latent image carrier (hereinafter also referred to as a photoreceptor), which includes a charging roller 117, a developing device 140 having a developing sleeve 102, a transfer charging roller 114, a cleaner container 116, and a fixing device. 126, a pickup roller 124, and the like are provided. The electrostatic latent image carrier 100 is charged by the charging roller 117. Then, exposure is performed by irradiating the electrostatic latent image carrier 100 with laser light from the laser generator 121, and an electrostatic latent image corresponding to the target image is formed. The electrostatic latent image on the electrostatic latent image carrier 100 is developed with a one-component toner by the developing device 140 to obtain a toner image, and the toner image is transferred in contact with the electrostatic latent image carrier via a transfer material. The image is transferred onto the transfer material by the roller 114. The transfer material on which the toner image is placed is conveyed to the fixing device 126 and fixed on the transfer material. Further, the magnetic toner partially left on the electrostatic latent image carrier is scraped off by the cleaning blade and stored in the cleaner container 116.

  Next, it describes regarding the measuring method of each physical property which concerns on this invention.

<Method of thermal conductivity>
(1) Preparation of measurement sample About 5 g of toner (variable according to the specific gravity of the sample) is compression-molded for 60 seconds at about 20 MPa using a tablet molding compressor in an environment of 25 ° C. Two cylinders having a diameter of 25 mm and a height of 6 mm are produced.

(2) Thermal conductivity measurement and measurement device: Hot disk method thermal property measurement device TPS2500S
Sample holder: Room temperature sample holder Sensor: Standard (RTK) Sensor software: Hot disk analysis 7
Place the measurement sample on the mounting table of the sample holder for room temperature, and adjust the height of the table so that the surface of the measurement sample is the same height as the sensor. Place the second measurement sample and the attached metal piece on the sensor, and apply pressure using the screw on the sensor. The pressure is adjusted to 30 cN · m with a torque wrench. Make sure that the center of the measurement sample and sensor is directly under the screw. Start hot disk analysis and select the experiment type Bulk (Type I). Enter the following in the input items.
Available Probing Depth: 6mm
Measurement time: 40s
Heating Power: 60mW
Sample Temperature: 23 ° C
TCR: 0.004679K ^-1
Sesor Type: Disk
Senor Material Type: Kapton
Sensor Design: 5465
Sensor Radius: 3.189mm

  After the input, measurement is started. After the measurement is completed, the Calculate button is selected, Start Point: 10 and End Point: 200 are input, the Standard Analysis button is selected, and Thermal Conductivity [W / mK] is calculated.

<Total Energy (TE) amount; measurement method of total energy>
TE in the present invention is measured using a powder fluidity analyzer (powder rheometer FT-4, manufactured by Freeman Technology) (hereinafter abbreviated as FT-4) equipped with a rotary propeller blade.

  Specifically, the measurement is performed by the following operation. In all operations, the propeller-type blade is a 23.5 mm diameter blade dedicated to FT-4 measurement (see FIG. 2A). The rotation axis is in the normal direction around the center of a 23.5 mm × 6.5 mm blade plate. The blade plate is smoothly twisted counterclockwise such that both outermost edge portions (12 mm from the rotating shaft) are 70 ° and a portion 6 mm from the rotating shaft is 35 ° (FIG. 2). (See (b)), and the material is SUS.

  First, a dedicated container for FT-4 measurement [a split container (model number: C4031) having a diameter of 25 mm and a volume of 25 ml, a height of about 51 mm from the bottom of the container to the split part. Hereinafter, it is also simply referred to as a container. The toner powder layer is formed by compressing 24 g of toner left in a 60 ° C. environment at 23 ° C. for 3 days.

  For compression of the toner, a compression test piston (diameter 24 mm, height 20 mm, lower mesh tension) is used instead of the propeller blade.

(1) Consolidation operation of toner 8 g of toner is added to the above-mentioned container exclusively for FT-4 measurement. A compression piston dedicated to FT-4 measurement is attached and consolidation is performed at 40N for 60 seconds. Further, 8 g of toner is added, and the compression operation is performed three times in a similar manner so that a total of 24 g of the compacted toner is in a dedicated container.

(2) Split operation A toner powder layer having the same volume (25 ml) is formed by scraping off the toner powder layer at the split portion of the above-described FT-4 measurement container and removing the toner on the toner powder layer.

(3) Measurement operation (A) The peripheral speed of the blade (the peripheral speed of the outermost edge of the blade) in the clockwise direction (the direction in which the toner powder layer is not pushed in by the rotation of the blade) with respect to the surface of the toner powder layer ) Is 10 mm / sec, and the angle between the trajectory drawn by the outermost edge of the moving blade and the surface of the powder layer (hereinafter referred to as “blade trajectory angle”) is the vertical entry speed to the toner powder layer. The propeller blade is advanced to a position 10 mm from the bottom of the toner powder layer at a speed of 5 (deg).

  (B) Thereafter, in the clockwise rotation direction with respect to the surface of the toner powder layer, the peripheral speed of the blade is set to 60 mm / sec. deg), and the propeller blade is advanced from the bottom of the toner powder layer to a position of 1 mm.

  (C) Thereafter, in the counterclockwise rotation direction with respect to the surface of the toner powder layer, the peripheral speed of the blade is 10 mm / sec, the extraction speed in the vertical direction from the toner powder layer is 5 The speed is set to (deg), and the blade is moved to a position of 80 mm from the bottom surface of the toner powder layer to perform extraction. When the extraction is completed, the toner attached to the blade is wiped off by rotating the blade alternately in small clockwise and counterclockwise directions.

  In the measurement operation (A), the propeller blade is rotated to enter the toner powder layer in the container, and the measurement is started from a position 60 mm from the bottom surface of the toner powder layer. TE is defined as the sum of rotational torque and vertical load obtained when the propeller-type blade is advanced. By dividing the obtained TE by the toner density in the cell at the time of measurement (the toner density is automatically measured by FT-4), [TE / density] in the present invention is obtained. The reason for dividing by the density is to eliminate factors such as filling efficiency during measurement.

<Method for measuring number average particle diameter of primary particles of silica fine particles>
The number average particle size of the primary particles of the silica fine particles is calculated from the silica fine particle image on the surface of the magnetic toner photographed by Hitachi Ultra High Resolution Field Emission Scanning Electron Microscope S-4800 (Hitachi High-Technologies Corporation). The image capturing conditions of S-4800 are as follows.

(1) Sample preparation A thin conductive paste is applied to a sample table (aluminum sample table 15 mm × 6 mm), and magnetic toner is sprayed thereon. Further, air is blown to remove excess magnetic toner from the sample stage and sufficiently dry. The sample stage is set on the sample holder, and the height of the sample stage is adjusted to 36 mm by the sample height gauge.

(2) S-4800 observation condition setting The number average particle diameter of the primary particles of the silica fine particles is calculated using an image obtained by the reflected electron image observation of S-4800. Since the reflected electron image has less charge-up of the silica fine particles than the secondary electron image, the particle size of the silica fine particles can be accurately measured.

  Liquid nitrogen is poured into the anti-contamination trap attached to the S-4800 mirror until it overflows, and is placed for 30 minutes. The “PC-SEM” of S-4800 is activated and flushing (cleaning of the FE chip as an electron source) is performed. Click the acceleration voltage display part of the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current by flashing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 mirror. Press [Origin] on the control panel to move the sample holder to the observation position.

  Click the acceleration voltage display section to open the HV setting dialog, and set the acceleration voltage to [0.8 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [Up (U)] and [+ BSE] for the SE detector, and select [+ BSE] in the selection box on the right. L. A. 100] to select a mode in which observation is performed with a reflected electron image. Similarly, in the [Basic] tab of the operation panel, the probe current of the electron optical system condition block is set to [Normal], the focus mode is set to [UHR], and the WD is set to [3.0 mm]. Press the [ON] button in the acceleration voltage display section of the control panel to apply the acceleration voltage.

(3) Calculation of number average particle diameter (D1) of silica fine particles (above da) Drag in the magnification display section of the control panel to set the magnification to 100000 (100k). The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Repeat this operation two more times to focus.

  Thereafter, the particle diameter of at least 300 silica fine particles on the surface of the magnetic toner is measured to obtain an average particle diameter. Here, since some silica fine particles exist as agglomerates, the number average particle size of primary particles of silica fine particles (by calculating the maximum diameter of those that can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter ( D1) Obtain (da).

  In order to eliminate the influence of silica particles having a relatively small particle diameter, the measurement of silica particles in the present invention was limited to those having a primary particle diameter of 20 nm or more.

<Method for Measuring Average Circularity of Magnetic Toner Particles>
The average circularity of the magnetic toner particles is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions at the time of calibration work (also measured in the case of magnetic toner).

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

  For the measurement, the above-mentioned flow type particle image analyzer equipped with “UPlanApro” (magnification 10 times, numerical aperture 0.40) as an objective lens is used, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. It was used. The dispersion prepared according to the above procedure is introduced into the flow type particle image analyzer, and 3000 magnetic toner particles are measured in the total count mode in the HPF measurement mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the equivalent circle diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the magnetic toner particles is obtained.

  In the measurement, automatic focus adjustment is performed using standard latex particles (eg, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the present invention, a flow type particle image measuring apparatus that has been calibrated by Sysmex Corporation and that has been issued a calibration certificate issued by Sysmex Corporation is used. Measurement is performed under the measurement and analysis conditions when the calibration certificate is received, except that the analysis particle diameter is limited to a circle equivalent diameter of 1.985 μm or more and less than 39.69 μm.

  The measurement principle of the flow-type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation) is to take a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is picked up by a CCD camera, and the picked-up image is image-processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image The projected area S, the peripheral length L, etc. are measured.

Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. Defined and calculated by the following formula.
Circularity = 2 × (π × S) ^1/2 / L

  When the particle image is circular, the circularity is 1.000. The greater the degree of irregularities on the outer periphery of the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

<Measurement method of true density of toner>
The true density of the toner was measured with a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). The conditions are as follows.
Cell: SM cell (10 ml)
Sample amount: about 2.0 g (toner), 0.05 g (silica fine particles)

  This measurement method measures the true density of a solid / liquid based on a gas phase substitution method. Similar to the liquid phase replacement method, it is based on Archimedes' principle, but uses a gas (argon gas) as a replacement medium, and therefore has high accuracy for micropores.

<Method for Measuring Toner Weight Average Particle Size (D4)>
The weight average particle diameter (D4) of the toner is calculated as follows (also calculated in the case of toner particles). As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with an aperture tube of 100 μm is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software is set as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikka Ki Bios) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker (1) installed in the sample stand, the electrolytic solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4).

<Method for measuring hydrolysis rate of silane compound>
The hydrolysis rate of the silane compound will be described. When the alkoxysilane is subjected to a hydrolysis treatment, a mixture composed of a hydrolyzate, an unhydrolyzed product, and a condensate is obtained. Described below is the ratio of hydrolyzate in the resulting mixture. This mixture corresponds to the silane compound described above.

First, the alkoxysilane hydrolysis reaction will be described by taking methoxysilane as an example. When methoxysilane is hydrolyzed, the methoxy group becomes a hydroxyl group and methanol is produced. Therefore, the progress of hydrolysis can be known from the quantitative ratio of methoxy group and methanol. In the present invention, the quantitative ratio was measured by ¹ H-NMR (nuclear magnetic resonance) to determine the hydrolysis rate. Taking methoxysilane as an example, specific measurement and calculation methods are shown below.

First, ¹ H-NMR (nuclear magnetic resonance) of methoxysilane before being subjected to hydrolysis treatment was measured using deuterated chloroform, and the peak position derived from the methoxy group was confirmed. Thereafter, hydrolysis treatment was performed on methoxysilane to obtain a silane compound, and the hydrolysis reaction was stopped by setting the silane compound aqueous solution just before being added to the untreated magnetic substance to pH 7.0 and a temperature of 10 ° C. . Water in the obtained aqueous solution was removed to obtain a dried silane compound. A small amount of deuterated chloroform was added to the dried product, and ¹ H-NMR was measured. The peak derived from the methoxy group in the obtained spectrum was determined based on the peak position confirmed in advance. The peak area derived from the methoxy group was defined as A, and the peak area derived from the methyl group of methanol was defined as B, and the hydrolysis rate was determined by the following equation.
Hydrolysis rate (%) = {B / (A + B)} × 100

The measurement conditions for ¹ H-NMR were set as follows.
Measuring apparatus: FT NMR apparatus JNM-EX400 (manufactured by JEOL Ltd.)
Measurement frequency: 400MHz
Pulse condition: 5.0μs
Frequency range: 10500Hz
Integration count: 1024 times Measurement temperature: 40 ° C

<Method of measuring acid value of polyester resin>
The acid value of the polyester resin is measured according to JIS K1557-1970. A specific measurement method is shown below. 2.0 g of the pulverized sample is precisely weighed (W (g)). A sample is put into a 200 ml Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (2: 1) is added and dissolved for 5 hours. Add phenolphthalein solution as indicator. 0.1N KOH is also titrated with a burette using an alcohol solution. The amount of the KOH solution at this time is S (ml). A blank test is performed, and the amount of the KOH solution at this time is defined as B (ml).

The acid value is calculated by the following formula.
Acid value = [(SB) × f × 5.61] / W
(F: Factor of KOH solution)

<Measurement method of amount of component eluted with styrene of silane compound contained in treated magnetic substance>
A glass vial having a capacity of 50 ml is charged with 20 g of styrene and 1.0 g of a treated magnetic substance, and the glass vial is set in “KM Shaker” (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd. The speed is set to 50 and shaken for 1 hour to elute the treatment agent in the treated magnetic material into styrene. Thereafter, the treated magnetic material and styrene are separated and sufficiently dried in a vacuum dryer.

  The carbon content per unit mass is measured with a HORIBA carbon / sulfur analyzer EMIA-320V for the dried processed magnetic material and the processed magnetic material before elution with styrene. Using the carbon amount value before and after elution of styrene, the elution rate of silane compound contained in the treated magnetic material into styrene is calculated. In addition, the sample preparation amount at the time of EMIA-320V measurement shall be 0.20g, and tungsten and tin are used as a combustion aid.

<Method for measuring iron element dissolution rate and silicon content>
In the present invention, the iron element dissolution rate of magnetic iron oxide and the content of metal elements other than iron with respect to the iron element dissolution rate can be determined by the following method. Specifically, 3 liters of deionized water is placed in a 5 liter beaker and heated with a water bath to 50 ° C. To this, 25 g of magnetic iron oxide is added and stirred. Then, special grade hydrochloric acid is added to make a 3 mol / L hydrochloric acid aqueous solution, and magnetic iron oxide is dissolved. Sampling is performed ten times or more from the start of dissolution until it is completely dissolved and transparent, filtered through a membrane filter having an opening of 0.1 μm, and the filtrate is collected. The filtrate is subjected to plasma emission spectroscopy (ICP) to quantify iron elements and metal elements other than iron elements, and the iron element dissolution rate of each sample is determined by the following equation.
Iron element dissolution rate = (iron element concentration in sample / iron element concentration when completely dissolved) × 100

  Further, the silicon content of each sample is obtained, and the silicon element dissolution rate is found up to 5% from the relationship between the iron element dissolution rate obtained by the above measurement and the element content detected at that time. The content of is determined.

  Hereinafter, the present invention will be specifically described with reference to production examples and examples, but this does not limit the present invention in any way. In addition, all the parts in the following mixing | blending are a mass part.

<Production Example 1 of Magnetic Iron Oxide>
Ferrous salt aqueous solution containing ferrous hydroxide colloid by mixing and stirring 50 liters of 4.0 mol / L sodium hydroxide aqueous solution with 50 liters of ferrous sulfate first aqueous solution containing 2.0 mol / L of Fe ²⁺ Got. This aqueous solution was kept at 85 ° C., and an oxidation reaction was performed while blowing air at 20 L / min to obtain a slurry containing core particles.

  The obtained slurry was filtered and washed with a filter press, and then the core particles were dispersed again in water and reslurried. To this reslurry liquid, sodium silicate that is 0.20% by mass in terms of silicon per 100 parts of the core particles is added, the pH of the slurry liquid is adjusted to 6.0, and the magnetic oxidation having a silicon-rich surface is performed by stirring. Iron particles were obtained. The obtained slurry was filtered and washed with a filter press, and further reslurried with ion-exchanged water. To this reslurry liquid (solid content 50 g / L), 500 g (10% by mass with respect to magnetic iron oxide) of ion exchange resin SK110 (manufactured by Mitsubishi Chemical) was added, and ion exchange was performed by stirring for 2 hours. Thereafter, the ion exchange resin was removed by filtration through a mesh, filtered and washed with a filter press, dried and crushed to obtain magnetic iron oxide 1 having a number average particle diameter of 0.23 μm.

<Production Example 2 of Magnetic Iron Oxide>
In the production of magnetic iron oxide 1, magnetic iron oxide 2 having a volume average particle size of 0.23 μm was obtained in the same manner except that the amount of sodium silicate added was changed to 0.05 part.

<Production Example 3 of Magnetic Iron Oxide>
In the production of magnetic iron oxide 1, magnetic iron oxide 3 having a volume average particle diameter of 0.23 μm was obtained in the same manner except that the amount of sodium silicate added was changed to 0.5 part.

<Production Example 4 of Magnetic Iron Oxide>
In the production of magnetic iron oxide 1, magnetic iron oxide 4 having a volume average particle size of 0.23 μm was obtained in the same manner except that the amount of sodium silicate added was changed to 0.01 parts.

<Production Example 5 of Magnetic Iron Oxide>
In the production of magnetic iron oxide 1, magnetic iron oxide 5 having a volume average particle size of 0.23 μm was obtained in the same manner except that the amount of sodium silicate added was changed to 0.55 parts.

<Production Example 1 of Comparative Magnetic Iron Oxide>
In the production of magnetic iron oxide 1, a comparative magnetic iron oxide 1 having a volume average particle diameter of 0.23 μm was obtained in the same manner except that the amount of sodium silicate added was changed to 0.1 part.

<Production Example 2 for Comparative Magnetic Iron Oxide>
After mixing 0.95 equivalent sodium hydroxide aqueous solution with respect to Fe ^<2+ > in the ferrous sulfate solution, the ferrous salt aqueous solution containing Fe (OH) ₂ was produced | generated. Then, sodium silicate was added so that it might become 1.0 mass% in conversion of a silicon element with respect to an iron element. Next, magnetic iron oxide particles containing silicon element are produced by aeration of ferrous salt aqueous solution containing Fe (OH) ₂ at a temperature of 90 ° C. and an oxidation reaction under conditions of pH 6 to 7.5. did.

Further, 1.05 equivalent of an aqueous sodium hydroxide solution in which 0.1% by mass of sodium silicate was dissolved (in terms of silicon element with respect to iron element) was added to this suspension with respect to the remaining Fe ²⁺ , and a temperature of 90 Magnetic iron oxide particles containing silicon element were generated by an oxidation reaction under the conditions of pH 8 to 11.5 while heating at 0 ° C.

  The produced magnetic iron oxide particles were filtered by a conventional method, washed and dried. Since the primary particles of the obtained magnetic iron oxide particles are aggregated to form aggregates, the aggregates are crushed using a mix muller to make the magnetic iron oxide particles primary particles and magnetic The surface of the iron oxide particles was smoothed to obtain Comparative Magnetic Iron Oxide Production Example 2 having the characteristics shown in Table 1. The average particle diameter of Comparative Magnetic Iron Oxide Production Example 2 was 0.21 μm.

<Production Example of Silane Compound 1>
30 parts of iso-butyltrimethoxysilane was added dropwise to 70 parts of ion exchange water with stirring. Thereafter, this aqueous solution was kept at pH 5.5 and a temperature of 55 ° C., and hydrolyzed by dispersing for 120 minutes at a peripheral speed of 0.46 m / s using a disper blade. Thereafter, the pH of the aqueous solution was adjusted to 7.0 and cooled to 10 ° C. to stop the hydrolysis reaction. Thus, an aqueous solution containing the silane compound 1 having a hydrolysis rate of 99% was obtained.

<Production example of silane compounds 2 to 7>
For silane compounds 2 to 7, silane compounds 2 to 7 were obtained in the same manner except that the type, pH, temperature, and time of the silane compound were changed as shown in Table 1 from the production example of silane compound 1. The physical properties of the obtained silane compound are summarized in Table 1. The silane compounds 6 and 7 are not hydrolyzed.

<Production example of magnetic body 1>
100 parts of magnetic iron oxide 1 was put into a high speed mixer (LFS-2 type, manufactured by Fukae Pautech Co., Ltd.), and 8.0 parts of an aqueous solution containing the silane compound 1 was added dropwise over 2 minutes while stirring at 2000 rpm. . Thereafter, the mixture was mixed and stirred for 5 minutes. Next, in order to enhance the fixing property of the silane compound, after drying at 40 ° C. for 1 hour to reduce moisture, the mixture was dried at 110 ° C. for 3 hours to proceed the condensation reaction of the silane compound. Thereafter, it was crushed, and a treated magnetic body 1 was obtained through a sieve having an opening of 100 μm. The physical properties of the magnetic body 1 are shown in Table 2.

<Manufacture of magnetic bodies 2-10>
In the production of the treated magnetic body 1, magnetic bodies 2 to 10 were obtained in the same manner except that the magnetic iron oxide, the silane compound and the addition amount thereof were changed as shown in Table 2. Table 2 shows the physical properties of the obtained magnetic substance.

<Production Example of Comparative Magnetic Material 1>
100 parts of magnetic iron oxide 1 is put into a high speed mixer (LFS-2 type manufactured by Fukae Pautech Co., Ltd.), and 8.3 parts of the aqueous solution containing the silane compound 1 is dropped over 2 minutes while stirring at a rotation speed of 2000 rpm. did. Then, it mixed and stirred for 3 minutes. Next, the mixture was dried at 120 ° C. for 1 hour, and the condensation reaction of the silane compound was allowed to proceed. Then, it was crushed and passed through a sieve having an opening of 100 μm to obtain a comparative magnetic body 1. Table 2 shows the physical properties of the obtained processed magnetic body 1.

<Example of production of magnetic body 2 for comparison>
In a ferrous sulfate aqueous solution, 1.0 to 1.1 equivalents of caustic soda solution (containing 1 mass% sodium hexametaphosphate in terms of P with respect to Fe) is mixed with iron ions, An aqueous solution containing ferrous iron was prepared. While maintaining the aqueous solution at pH 9, air was blown in, and an oxidation reaction was performed at 80 ° C. or higher and 90 ° C. or lower to prepare a slurry liquid for generating seed crystals.

  Then, after adding ferrous sulfate aqueous solution so that it becomes 0.9 equivalent or more and 1.2 equivalent or less with respect to the original alkali amount (sodium component of caustic soda) to this slurry liquid, the slurry liquid is maintained at pH 8, The oxidation reaction proceeds while blowing air. At the end of the oxidation reaction, the pH was adjusted to about 6, and 1.0 part of n-hexyltrimethoxysilane was added as a silane coupling agent to 100 parts of magnetic iron oxide, followed by thorough stirring. The produced hydrophobic iron oxide particles were washed, filtered and dried by a conventional method, and then the agglomerated particles were pulverized to obtain a comparative magnetic body 2. Table 2 shows the physical properties of the obtained magnetic substance.

<Example of production of magnetic body 3 for comparison>
100 parts of comparative magnetic iron oxide 2 was put into a Simpson MixMuller, and 3 parts of a 10% by weight methanol solution of decyltrimethoxysilane having an alkyl group with 10 carbon atoms as a silane coupling agent (decyltrimer). Methoxysilane (0.3 parts equivalent) was sprayed uniformly. Thereafter, by operating for 45 minutes in a temperature range of 50 to 60 ° C., the surface of the magnetic iron oxide particles for comparison is coated with the silane coupling agent, and volatile components such as methanol are vaporized to form decyl groups on the surface. A comparative magnetic body 3 was obtained. Table 2 shows the physical properties of the obtained magnetic substance.

<Manufacture of magnetic toner particles 1>
After adding 450 parts of 0.1 mol / L-Na ₃ PO ₄ aqueous solution to 720 parts of ion-exchanged water and heating to 60 ° C., 67.7 parts of 1.0 mol / L-CaCl ₂ aqueous solution was added. An aqueous medium containing a dispersion stabilizer was obtained.
・ Styrene 79.0 parts ・ N-Butyl acrylate 21.0 parts ・ Divinylbenzene 0.6 parts ・ Monoazo dye iron complex (T-77: Hodogaya Chemical Co., Ltd.) 1.5 parts ・ Magnetic substance 1 90.0 parts Saturated polyester resin 7.0 parts (saturated polyester resin obtained by condensation reaction of bisphenol A ethylene oxide adduct and terephthalic acid; Mn = 5000, acid value = 6 mgKOH / g, Tg = 68 ° C.)
3.0 parts The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Chemical Co., Ltd.) to obtain a monomer composition. This monomer composition was heated to 63 ° C., and 15 parts of dibehenyl sebacate (melting point: 73 ° C.) and 10 parts of paraffin wax (HNP-9: manufactured by Nippon Seiwa Co., Ltd.) were added and mixed there. And dissolved. Thereafter, 7.0 parts of disecondary butyl peroxydicarbonate (10 hour half-life temperature 51 ° C.) was dissolved as a polymerization initiator.

The monomer composition was charged into the aqueous medium, and granulated by stirring at 12,000 rpm for 10 minutes in a TK homomixer (Special Machine Industries Co., Ltd.) in an N ₂ atmosphere at 60 ° C. Thereafter, the mixture was reacted at 70 ° C. for 6 hours while stirring with a paddle stirring blade. After completion of the reaction, the suspension was cooled, washed with hydrochloric acid, filtered and dried to obtain toner particles 1.

<Production of Magnetic Toner Particles 2-24 and Comparative Toners 1-10>
In the production of the magnetic toner particles 1, the magnetic toner particles 2 to 24 and the comparison were made in the same manner as in the production of the toner 1 except that the type, amount, and rotational speed at the time of granulation were changed as shown in Table 3. Magnetic toner particles 1 to 10 were obtained. Table 3 summarizes the physical properties of the obtained toner.

<Manufacture of silica fine particles 1>
The mixture was heated to 35 ° C. in the presence of methanol, water and ammonia water, and tetramethoxysilane was added dropwise with stirring to obtain a suspension of silica fine particles. Solvent substitution was performed, and hexamethyldisilazane was added to the obtained dispersion as a hydrophobizing agent at room temperature, followed by heating to 130 ° C. for reaction, thereby hydrophobizing the surface of the silica fine particles. Silica fine particles 1 (sol-gel silica) were obtained by passing through a sieve in a wet manner to remove coarse particles, then removing the solvent and drying. The silica fine particles 1 are shown in Table 4.

<Production Examples 2 to 5 of silica fine particles>
Silica fine particles 2 to 5 were obtained in the same manner as in silica fine particle production example 1 except that the reaction temperature and the stirring speed were appropriately changed. The silica fine particles 2 to 5 are shown in Table 4.

<Manufacture of magnetic toner 1>
100 parts of toner particles, 0.5 parts by mass of hydrophobic silica fine particles having a number average primary particle size of 8 nm, 0.5 parts by mass of silica fine particles 1 having a number average primary particle size of 35 nm, a Henschel mixer (Mitsui Miike Chemical Industries, Ltd.) To obtain a toner 1 having a weight average particle diameter (D4) of 7.8 μm. Table 5 summarizes the physical properties of the magnetic toner 1 obtained.

<Manufacture of magnetic toners 2 to 24 and comparative toners 1 to 10>
In the production of magnetic toner 1, 0.5 parts by mass of hydrophobic silica fine particles having a number average primary particle size of 8 nm were fixed, and the type, amount and external strength of the second type of silica fine particles were changed as shown in Table 5. Except for the above, magnetic toner particles 2 to 24 and comparative magnetic toner particles 1 to 10 were obtained in the same manner as in the production of toner 1. Table 5 summarizes the physical properties of the obtained toner.

<Example 1>
The following evaluation was performed using toner 1.

As the image forming apparatus, a commercially available LaserJet P2055 (manufactured by Hewlett Packard) was used, and the printing speed was changed from 35 sheets / minute to 41 sheets / minute. The paper type used was a commercially available A4 paper Red Label (80 g / m ² ).

  The evaluation environment was a high temperature and high humidity (35.0 ° C./80%) environment severe to endurance deterioration, and the density and fog evaluation after initial and after 10000 sheets durability were performed. The following evaluation was performed using the toner 1, and good results were obtained in all the evaluations. The evaluation results are shown in Table 6.

  The evaluation methods for each evaluation performed in the examples and comparative examples of the present invention and the judgment criteria thereof will be described below.

[Evaluation of initial concentration in high temperature and high humidity environment]
The initial five solid black images were output, and the density of the solid black image was measured with a Macbeth reflection densitometer (manufactured by Macbeth). The average reflection density of five initial solid black images was calculated and used as the initial solid black density. The criteria for evaluating the reflection density are as follows. The evaluation results are shown in Table 6.
A: 1.45 or more B: 1.35 or more and less than 1.45 C: 1.25 or more and less than 1.35 D: 1.15 or more and less than 1.25 E: less than 1.15

[Durability concentration evaluation under high temperature and high humidity environment]
After the initial 5 solid black images are output, 10000 horizontal line images with a printing rate of 2% are output intermittently for 2 seconds for 4 seconds, and then 5 solid black images are output. The solid black density after durability was used. The judgment criteria are shown below. The evaluation results are shown in Table 6.
A: 1.40 or more B: 1.30 or more and less than 1.40 C: 1.20 or more and less than 1.30 D: 1.10 or more and less than 1.20 E: less than 1.10

[Evaluation of fog on initial photoconductor in high temperature and high humidity environment]
More rigorous toner fogging evaluation was performed by evaluating the fogging state of the toner on the photoconductor so as not to be affected by the transfer and fixing processes. Specifically, in the initial fog evaluation, two solid white images were output, and the fog state on the second photoconductor was evaluated.

The apparatus is stopped at the timing when the toner flies to the photoconductor during image output, and the toner on the photoconductor is collected with a tape. The tape was affixed on paper, and the reflectance was measured from above the tape using a REFECTMETER MODEL TC-6DS manufactured by Tokyo Denshoku. A green filter was used as the filter. The reflectance was measured in the same manner for the tape with only the tape attached, and the fog was calculated using the following formula.
Fogging on photoconductor (reflectance) (%) = reflectance (%) of the tape on which the toner on the photoconductor is collected is affixed to standard paper-reflectivity (%) of the tape only affixed to standard paper

Judgment criteria are as follows.
A: Less than 4% B: 4-6%
C: 6-8%
D: 8-10%
E: 10% or more

[Evaluation of fog on photoconductor after endurance in high temperature and high humidity environment]
After outputting 10,000 horizontal lines with a printing rate of 2% in two intermittent modes in 4 seconds, toner fogging on the photoconductor was evaluated in the same manner as in the initial stage. Judgment criteria are as follows.
A: Less than 4% B: 4-6%
C: 6-8%
D: 8-10%
E: 10% or more

<Examples 2 to 24 and Comparative Examples 1 to 10>
As toner, toners 2 to 24 and comparative toners 1 to 10 were used, and toner evaluation was performed under the same conditions as in Example 1. The evaluation results are shown in Table 6.

  100: electrostatic latent image carrier (photoconductor), 102: toner carrier, 103: developing blade, 114: transfer member (transfer charging roller), 116: cleaner container, 117: charging member (charging roller), 121: Laser generator (latent image forming means, exposure device), 123: laser, 124: pickup roller, 125: transport belt, 126: fixing device, 140: developing device, 141: stirring member

Claims (10)

A magnetic toner containing magnetic toner particles containing a binder resin and a magnetic material, and inorganic fine particles,
The magnetic toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
The inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of primary particles of 30 nm to 200 nm,
The magnetic toner contains 0.1 to 3.0 parts by mass of the silica fine particles with respect to 100 parts by mass of the magnetic toner particles;
The ratio of the total energy (mJ) of the magnetic toner and the true density (g / ml) of the magnetic toner, measured by a powder flowability measuring device, is 200 mJ / (g / ml). ) A magnetic toner, wherein the magnetic toner is 400 mJ / (g / ml) or less. The magnetic toner according to claim 1, wherein the magnetic toner has a dielectric loss tangent tan δ of 1.0 × 10 ⁻² or more and 2.0 × 10 ⁻² or less.   The magnetic toner according to claim 1 or 2, wherein the magnetic toner has an average circularity of 0.960 or more.   The magnetic toner according to claim 1, wherein the magnetic material is a treated magnetic material obtained by surface-treating magnetic iron oxide with a silane compound.   The magnetic iron oxide has a silicon element on the surface, and the amount of silicon eluted when the magnetic iron oxide is dissolved until the dissolution rate of the iron element reaches 5.00% by mass, the magnetic iron oxide The magnetic toner according to claim 4, wherein the toner is 0.05% by mass or more and 0.50% by mass or less as a reference.   5. The residual carbon amount derived from the silane compound after washing the treated magnetic material with styrene is 0.40% by mass or more and 1.20% by mass or less based on magnetic iron oxide. Or 5. Magnetic toner according to 5.   The magnetic toner according to any one of claims 4 to 6, wherein the silane compound is a silane compound obtained by subjecting alkoxysilane to hydrolysis until the hydrolysis rate becomes 50% or more. 8. The magnetic toner according to claim 1, wherein a volume specific heat of the silica fine particles at 50 ° C. is 5000 J / (cm ³ · K) or more and 10000 J / (cm ³ · K) or less. .   The magnetic toner according to claim 1, wherein the magnetic toner particles are toner particles produced in an aqueous medium.   The magnetic toner according to claim 1, wherein the magnetic toner particles are toner particles produced by a suspension polymerization method.

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