JP6385140B2 - toner - Google Patents

Description

  The present invention relates to a 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, downsizing and energy saving of the apparatus are progressing, and a one-component developing system using toner that is advantageous in these respects is preferably used.

  In order to cope with the recent improvement in image quality and energy saving, optimization of each process is important in each process of electrophotography. Among them, especially for energy saving, it is important that the toner is sufficiently fixed on the medium even when the temperature of the fixing device is relatively low. Therefore, the toner is required to have a low-temperature fixing type configuration that easily melts and deforms even at a low temperature. On the other hand, it is necessary to design the toner so that the toner does not aggregate when it is exposed to a high temperature environment in distribution or storage in a warehouse. That is, the storage stability of toner and the low-temperature fixability are in a trade-off relationship. Nowadays, opportunities for worldwide use of copiers and printers are increasing, and the storability requirements for toner are becoming stricter than in the past. Considering various storage conditions, in particular, in an environment where high temperature and low temperature environments are repeated, the toner is aged and the low melting point component in the toner exudes to the toner surface. Is a more severe environment (in the present invention, this environment is called a severe environment).

  In general, it is said that a toner having a core-shell structure is advantageous from the viewpoint of achieving both low-temperature fixability and storage stability. For example, in Patent Document 1, the relationship between the Tg of the core and the shell is defined. In this case, the core is designed for low temperature fixability and the shell is designed for storage stability. Among them, we are committed to reducing the hindrance of low-temperature fixability by further improving the shell design.

  However, in the shell design for ensuring the storage stability, it is difficult to completely eliminate an inhibitory factor to the fixing property to the recent low-temperature fixing toner. For this reason, there is a demand for the creation of innovative technologies that improve storage stability without impairing low-temperature fixability.

JP 2002-91060 A

  An object of the present invention is to provide a toner capable of solving the above problems. Specifically, it is an object of the present invention to provide a toner capable of obtaining a stable high-quality image regardless of the use environment. An object of the present invention is to provide a toner having good storage stability in a harsh environment and good low-temperature fixability.

  The present inventors have found that the problems can be solved by controlling the thermal conductivity of the toner and the surface free energy of the toner within a certain range, and have completed the present invention.

That is, the present invention is a toner having toner particles containing a binder resin and a colorant, and inorganic fine particles,
The thermal conductivity of the toner is 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
Ri surface free energy 30.0mJ / m ² or more 50.0mJ / m ² or less der of the toner,
The colorant is related toner wherein processing magnetic der Rukoto that the magnetic iron oxide surface treated with a silane compound.

  It is possible to provide a toner capable of obtaining a stable and high-quality image regardless of the use environment. It is possible to provide a toner having good storage stability in a harsh environment. It is possible to provide a toner having good low-temperature fixability.

1 is a diagram illustrating an example of an image forming apparatus. It is a schematic diagram which shows an example of the mixing processing apparatus which can be used for the external addition mixing of inorganic fine particles. It is a schematic diagram which shows an example of a structure of the stirring member used for a mixing processing apparatus. It is a schematic diagram which shows the temperature setting of the thermostat used for evaluation of the preservability. It is a schematic diagram which shows the temperature setting of the thermostat used for evaluation of the preservability.

The present invention relates to a toner having toner particles containing a binder resin and a colorant and inorganic fine particles, and the toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m K) or less, and the surface free energy of the toner is 30.0 mJ / m ² or more and 50.0 mJ / m ² or less.

According to the study by the present inventors, by using the above toner, a toner capable of stably obtaining a high-quality image regardless of the use environment and having both good storage stability and storage stability even in a harsh environment is provided. I found out that I can do it. Its configuration requirements are
-Controlling the thermal conductivity of the toner to 0.230 W / (m · K) or more and 0.270 W / (m · K) or less.
-The surface free energy of the toner is controlled to 30.0 mJ / m ² or more and 50.0 mJ / m ² or less.
It is.

  The thermal conductivity of the toner of the present invention is in a higher range than before. When the thermal conductivity of the toner is increased, heat can be efficiently transferred from the fixing device to the toner on the medium, and low-temperature fixability can be achieved. On the other hand, from the viewpoint of the storage stability of the toner, by increasing the thermal conductivity, heat is easily transferred from the toner surface to the inside, and the toners are easily melt-bonded, which is disadvantageous for storage stability.

  Thus, it is difficult to achieve both low-temperature fixability and storage stability simply by controlling the thermal conductivity to be high.

  Next, the phenomenon of toner storability will be described. Generally, at a temperature equal to or higher than the glass transition point (Tg) of the toner, a movable molecular chain among the resin components contained in the toner starts to move freely. When the toner is exposed to the temperature of the glass transition point (Tg) of the toner, when one toner particle is present in isolation, the toner maintains its original shape without deformation. However, as the temperature becomes higher than the glass transition point (Tg), the toner is easily deformed. When the toner is transported in a container or mounted in a cartridge or the like, each toner particle is under pressure due to the weight of the surrounding toner particles, and therefore has a temperature higher than the glass transition point (Tg). Then, the toners are melt-bonded.

  On the other hand, the present inventors have found that, by controlling the thermal conductivity to be high and controlling the surface free energy within a certain range, it is possible to achieve storage stability that is much superior to that of the prior art.

  The surface free energy of the toner of the present invention is in a higher range than before. The surface free energy indicates the magnitude of energy for reducing the surface area of a substance. For example, consider a two-phase (solvent A, droplet B) emulsion system. If the surface free energy of the droplet B is small, the droplet B interface cannot be maintained and the droplet B is compatible with the solvent A. That is, the droplet B cannot keep its shape. On the other hand, when the surface free energy of the droplet B is very large, the droplets of the droplet B are united with each other to reduce the total area of the emulsion B interface. Similarly, the droplet B cannot keep its shape. Thus, in the above-described emulsion system, the surface free energy of the droplet B has an appropriate range in order to maintain the droplet shape.

On the other hand, when the toner is exposed to a high temperature exceeding the glass transition point (Tg) (for example, glass transition point (Tg) + 5 ° C.), the toner having high thermal conductivity has an effect such as the stability of the emulsion described above. The present inventors have found that the above can be obtained. Indeed, when the toner is exposed to an environment with a glass transition point (Tg) + 5 ° C., the toner does not behave like a liquid. However, it is presumed that, among the resin components contained in the toner, as the movable molecular chain starts to move freely, the effect of the surface stability similar to the stability of the droplet appears in a pseudo manner. Thus, in order to obtain stable storage stability, the surface free energy of the toner is set to 30.0 mJ / m ² or more and 50.0 mJ / m ² or less in order to exhibit the above-described effect of droplet stability. I found it to be control.

When the surface free energy of the toner is less than 30.0 mJ / m ² , the surface free energy is too low, and it becomes difficult to maintain toner particles in a harsh environment, and toner deformation cannot be suppressed. When the surface free energy of the toner is higher than 50.0 mJ / m ² , the surface free energy is too high and the toner particles may be united. A preferable range of the surface free energy is 33.0 mJ / m ² or more and 45.0 mJ / m ² or less.

  Furthermore, in order to exhibit the above-described effects, it is necessary to control the thermal conductivity of the toner within a relatively high range of 0.230 W / (m · K) to 0.270 W / (m · K). is there. When the surface free energy is included in the above range and the thermal conductivity is lower than the above range, the storage stability is deteriorated when the storage stability is evaluated in a severe environment. That is, the present inventors have found that the combination of the thermal conductivity and the surface free energy is superior in storage stability than the toner having only a low thermal conductivity. The reason is as follows. When the thermal conductivity is low, when the toner receives heat, it is difficult to transfer heat from the heat-received portion, so that heat is held only at that portion. As a result, it is considered that the entire surface of the toner particles is not uniform and does not behave like the above-described emulsion, so that the effect of surface free energy cannot be obtained. On the other hand, in the range where the thermal conductivity of the toner is higher than 0.270 W / (m · K), heat is easily transmitted to the inside of the toner. In some cases, the toner deformation cannot be suppressed due to the weight of the toner.

  In order to control the surface free energy of the toner, for example, the type and amount of the external additive and the presence of the external additive on the toner particles can be controlled. Further, as a toner particle, when a metal piece or the like is exposed from the surface of the toner particle, the surface free energy may be significantly reduced.

  The thermal conductivity of the toner can be controlled by including a metal powder or metal oxide having high heat conductivity in the toner. In addition, it is necessary to control the presence state in these toners. In the present invention, although the dispersed state of the magnetic material is a uniform state between the particles, considering the toner as a single particle, it is dispersed near the surface to increase the thermal conductivity.

  The magnetic material used in the toner of the present invention is preferably a 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.

  In addition, when a magnetic material hydrophobized with a silane compound is used, when the magnetic material is exposed from the toner surface, the surface free energy is not significantly reduced. On the other hand, when a magnetic material that is not treated with a silane compound or the like is exposed from the toner surface, the surface free energy may be significantly reduced, and it may be difficult to control the surface free energy range suitable for the present invention. is there.

  Similarly, when the thermal conductivity is increased by using a metal piece or the like, it is preferable to use a metal piece that has been subjected to a hydrophobization treatment in order not to reduce the surface free energy.

  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 (the amount of silicon present on and around the magnetic iron oxide) is 0.05% by mass or more and 0.50% by mass or less with respect to the magnetic iron oxide. It becomes.

  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. For this reason, when a storage test in a harsh environment is performed, heat is uniformly transmitted to the toner, and it becomes easy to obtain an effect of storage stability due to surface free energy.

  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, The dispersibility of the magnetic substance inside the toner may be inferior.

  Further, in order to control the surface state of such a magnetic material, it is necessary to control the toner manufacturing process manufactured according to 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 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 the 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. In addition, by forming a hydrogen bond, volatilization of the silane compound can be suppressed during heating.

  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, when a storage test in a harsh environment is performed, heat is uniformly transmitted to the toner, and it becomes easy to obtain an effect of storage stability due to surface free energy. Furthermore, the uniformity between the toners is increased, and the toner charge is stable even when the toner is continuously used, for example, in an endurance test. As a result, a stable image can be obtained, which is preferable. 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 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 the gas phase with a silane compound (hereinafter also referred to as a dry method), which improves the dispersibility of the magnetic material between the toners produced by the present invention. Preferred to achieve. 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 material while trapping water, the hydrophilic group remains on the surface of the magnetic material 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 toner produced by the present invention is improved. As a result, it is possible to further improve the dispersibility of the magnetic material, and when conducting a storage test in a harsh environment, heat is uniformly transmitted to the toner, and it becomes easy to obtain the storage stability effect due to surface free energy.

  Hereinafter, details of a method for producing a magnetic material used in the 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 3.0 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 3.0 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 magnetic material is greatly increased, and the rise of charging of the toner is accelerated.

  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, preferably a BET specific surface area of less 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. 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 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 magnetic bodies in the field of view are measured with a transmission electron microscope (TEM) with a photograph with 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 magnetic material. It is also possible to measure the particle size with an image analyzer.

  The magnetic material used in the 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 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 magnetic material amount.

  The weight average particle diameter (D4) of the toner produced according to the present invention is preferably 3.0 μm or more and 12.0 μm or less, and 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 toner produced according to the present invention preferably has an average circularity of 0.960 or more, and more preferably a mode circularity of 0.970 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. In addition, since toner with a high degree of circularity has a stable surface shape from the viewpoint of surface free energy, it is easy to obtain the effect of storage stability due to surface free energy when performing storage tests in harsh environments. Become.

  Examples of the binder resin used in the toner produced according to the present invention include styrene such as polystyrene and polyvinyltoluene, and homopolymers thereof and styrene-propylene copolymers, styrene-vinyltoluene copolymers, and 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 Styrene copolymers such as styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin can be used, and these can be used alone or in combination of two or more. Can be used. Of these, styrene-acrylic resins are particularly preferred from the standpoints of development characteristics and fixing properties.

  To the toner produced according to the present invention, a charge control agent may be blended as necessary to improve 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. .

  In the toner produced according to the present invention, a release agent may be blended as necessary to improve the fixing property. 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 toner of the present invention, it is preferable to contain 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 from the viewpoint of compatibility between 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 preferably used in the present invention will be described.

  The suspension polymerization method is a method in which a polymerizable monomer and a pigment or a magnetic material (further, 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 meter 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 easy to control the degree of circularity high and is preferable for achieving the degree of circularity suitable for the present invention. 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 storage stability and durability of the toner.

  In the present invention, the glass transition temperature Tg of the toner is preferably 40 ° C. or higher and 60 ° C. or lower. By satisfying this range, it becomes easy to achieve both low-temperature fixability and storage stability. The effect of storage stability according to the present invention is exhibited even at a temperature higher than the Tg of the toner. In order to control the Tg of the toner, it is possible to lower the Tg by changing the composition of the binder resin or using a release agent having a low melting point.

  The polymerization initiator used in the production of the toner produced by the present invention by the polymerization method has a half-life of 0.5 hours or more and 30.0 hours or less in the polymerization reaction in order to control the meltability of the toner. Those 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 10.0 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. Among the peroxide-based initiators, those selected from peroxydicarbonate and diacyl peroxide are particularly preferable. Specific examples of the polymerization initiator include diisopropyl peroxydicarbonate, disec-butyl peroxydicarbonate, isobutyryl peroxide and the like.

  In the production of the 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 for producing the toner produced according to the present invention by the polymerization method, generally, the above-described toner composition or the like is appropriately added, and uniformly dissolved or dispersed by a dispersing machine such as a homogenizer, a ball mill, or an ultrasonic dispersing machine. The polymerizable 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 case of producing the 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 toner 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 toner of the present invention contains toner particles and inorganic fine particles. In order to control the surface free energy within a suitable range, inorganic fine particles subjected to a hydrophobization treatment are preferable, and among these, silica, titanium oxide, alumina and the like are preferable. Among these, it is preferable to use silica fine particles because the volume specific heat described later can be easily adjusted to a suitable range in the present invention and good developability can be obtained.

As the silica fine particles, for example, both a 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 or the like can be used. . 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, the amount of inorganic fine particles added is 0.1 to 5.0 parts by mass, preferably 0.3 to 2.0 parts by mass, and 0.3 to 0.3 parts by mass with respect to 100 parts by mass of toner particles. It is preferable that it is not less than 0.8 parts by mass. When the added amount of the inorganic fine particles is within the above range, the toner can be given good fluidity and the fixing property is hardly hindered. In addition, it becomes easy to control the surface free energy in the present invention within a suitable range.

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

In the toner of the present invention, the coverage X1 with the inorganic fine particles on the toner surface obtained by an X-ray photoelectron spectrometer (ESCA) is preferably 40.0 area% or more and 70.0 area% or less. It is preferable that the diffusion index calculated | required from Formula 1 is 0.40 or more. Here, when a plurality of inorganic fine particles are added, the coverage X1 of the inorganic fine particles having the smallest number average particle diameter (D1) is shown.
(Formula 1) Diffusion index = X1 / X2

  The coverage X1 is a ratio of the detected intensity of the metal element contained in the inorganic fine particles when the toner is measured to the detected intensity of the metal element contained in the inorganic fine particles when the inorganic fine particles are measured by ESCA. From this, it can be calculated. The coverage X1 indicates the proportion of the area of the toner particle surface that is actually covered with inorganic fine particles.

  When the coverage X1 is 40.0 area% or more and 70.0 area% or less, it is possible to ensure the developability and durability of the toner as long as the low-temperature fixability is relatively not impaired.

On the other hand, the theoretical coverage X2 by the inorganic fine particles is calculated by the following formula 2 using the number of parts by mass of the inorganic fine particles per 100 parts by mass of the toner particles, the particle size of the inorganic fine particles, and the like. This indicates the ratio of the area that can theoretically cover the toner particle surface.
(Formula 2) Theoretical coverage X2 (area%) = 3 ^1/2 / (2π) × (dt / da) × (ρt / ρa) × C × 100
da: Number average particle diameter of the inorganic fine particles (D1)
dt: weight average particle diameter of toner (D4)
ρa: true specific gravity of inorganic fine particles ρt: true specific gravity of toner C: mass of inorganic fine particles / mass of toner (C uses the content of inorganic fine particles in the toner described later)

  The physical meaning of the diffusion index represented by the above formula 1 is shown below.

  The diffusion index indicates the difference between the actual coverage ratio X1 and the theoretical coverage ratio X2. The degree of this divergence is considered to indicate the number of inorganic fine particles stacked in two or three layers in the vertical direction from the toner particle surface. Ideally, the diffusion index is 1, but this is a case where the coverage ratio X1 coincides with the theoretical coverage ratio X2, and is a state where there are no inorganic fine particles laminated in two or more layers. On the other hand, when the inorganic fine particles are present on the toner surface as aggregated secondary particles, a difference between the actually measured coverage and the theoretical coverage is generated, and the diffusion index is lowered. In other words, the diffusion index can be paraphrased as indicating the amount of inorganic fine particles present as secondary particles.

  In the present invention, in order to obtain good storage stability, it is important to maximize the effect of surface free energy. For this purpose, the thermal conductivity is uniform at various locations on the toner surface. This is very important. The toner having the high diffusion index described above shows a state where the amount of inorganic fine particles present as secondary particles is small and the external additive coats the toner particles more uniformly. The higher the diffusion index, the better the storage stability. In particular, the diffusion index is preferably 0.40 or more. The surface free energy of the toner can be increased by increasing the diffusion index and increasing the coverage X1.

  The inorganic fine particles used in the present invention are preferably hydrophobized with silicone oil. The toner externally added with silica fine particles treated with silicone oil can be controlled to have a high surface free energy. Moreover, the hydrophobicity of the silica fine particles can be sufficiently imparted, and it is easy to suppress a decrease in chargeability even in a high temperature and high humidity environment. By increasing the number of treated portions of silicone oil, it is possible to increase the surface free energy of the toner.

  In addition, it is desirable that the inorganic fine particles used in the present invention be hydrophobized with 10 to 40 parts by mass of silicone oil with respect to 100 parts by mass of the inorganic fine particle base. A more preferable range is 20 parts by mass or more and 35 parts by mass or less. Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.

  The inorganic fine particles used in the present invention preferably have a carbon oil-based immobilization ratio of 85% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less. By controlling the immobilization rate in such a high range, the fluidity of the toner can be kept good even with the toner externally added with inorganic fine particles containing a large amount of silicone oil as in the present invention. It becomes possible. As a result, a toner having excellent durability and stability when used for a long time can be obtained. Furthermore, the immobilization rate of 85% by mass or more indicates that one end of the majority of the silicone oil is immobilized, which makes it difficult for the liquid crosslinking of the silicone oil to decrease, Storage stability can also be improved.

  In order to increase the immobilization rate of the silicone oil based on the carbon amount in the inorganic fine particles, it is necessary to chemically immobilize the silicone oil on the surface of the inorganic fine particles in the step of hydrophobizing the inorganic fine particles with the silicone oil. . For that purpose, for example, in order to promote the chemical reaction of silicone oil, the heat treatment step is preferably performed at 100 ° C. or higher, and the higher the heat treatment temperature, the higher the immobilization rate.

  The inorganic fine particles used in the present invention are preferably those obtained by treating the raw inorganic fine particles with silicone oil and then treating with at least one of alkoxysilane and silazane. Since the surface of the untreated inorganic fine particle base material remaining by this treatment can be hydrophobized, it is possible to stably obtain silica particles having a high hydrophobicity. Furthermore, even if the toner is externally added with inorganic fine particles containing a large amount of silicone oil, the fluidity of the toner can be kept good. In addition, since alkoxysilane and silazane are present on the outermost surface of the inorganic fine particles, liquid crosslinking of the silicone oil hardly occurs and the storage stability of the toner can be greatly improved. In addition, when hydrophobizing at least one of silicone oil, alkoxysilane, and silazane, the immobilization rate can be increased by treating the silicone oil with the inorganic fine particle precursor first.

The inorganic fine particles used in the present invention preferably have a volume specific heat at 50 ° C. of from 5000 J / (cm ³ · K) to 10,000 J / (cm ³ · K). By using the inorganic fine particles having a high volumetric specific heat, in addition to the uniform heat conduction according to the present invention, the inorganic fine particles can receive the heat due to a rapid temperature change, and the storage stability of the toner is easily improved. In particular, when the volume specific heat is 5000 J / (cm ³ · K) or more, the storage stability of the toner is remarkably improved. In order to control the volume specific heat within the above range, the amount of fine pores is controlled in the production process of the inorganic fine particle raw material. For example, in fine silica particles produced by a so-called dry method, the amount of pores is changed by controlling the generation temperature. By increasing the amount of pores, the specific volume heat can be increased.

  As a mixing processing apparatus for externally mixing the inorganic fine particles, a known mixing processing apparatus can be used, but an apparatus as shown in FIG. 2 is preferable in that the coverage X1 and the diffusion index can be easily controlled.

  FIG. 2 is a schematic view showing an example of a mixing treatment apparatus that can be used when externally adding and mixing inorganic fine particles used in the present invention.

  The mixing device is configured to take a share in a narrow clearance portion with respect to the toner particles and the inorganic fine particles, so that the inorganic fine particles adhere to the toner particle surface while loosening the secondary fine particles from the primary particles to the primary particles. can do.

  Furthermore, as will be described later, the coverage X1 and the diffusion index are preferred ranges in the present invention in that the toner particles and the inorganic fine particles are easily circulated in the axial direction of the rotating body, and are sufficiently uniformly mixed before the fixing proceeds. Easy to control.

  On the other hand, FIG. 3 is a schematic diagram showing an example of the configuration of the stirring member used in the mixing treatment apparatus.

  Hereafter, the external addition mixing process of the said inorganic fine particle is demonstrated using FIG.2 and FIG.3.

  The mixing processing apparatus for externally mixing the inorganic fine particles has a rotating body 2 having at least a plurality of stirring members 3 installed on the surface, a drive unit 8 that rotationally drives the rotating body, and a gap between the stirring member 3 and The main body casing 1 is provided.

  The clearance (clearance) between the inner peripheral portion of the main body casing 1 and the stirring member 3 gives a uniform share to the toner particles and easily adheres to the toner particle surface while loosening the inorganic fine particles from the secondary particles to the primary particles. In order to do this, it is important to keep it constant and minute.

  Further, in this apparatus, the diameter of the inner peripheral portion of the main body casing 1 is not more than twice the diameter of the outer peripheral portion of the rotating body 2. 2 shows an example in which the diameter of the inner peripheral portion of the main body casing 1 is 1.7 times the diameter of the outer peripheral portion of the rotating body 2 (the diameter of the body portion obtained by removing the stirring member 3 from the rotating body 2). If the diameter of the inner peripheral portion of the main body casing 1 is less than or equal to twice the diameter of the outer peripheral portion of the rotating body 2, the processing space in which the force acts on the toner particles is appropriately limited. A sufficient impact force is applied to the inorganic fine particles.

  It is important to adjust the clearance according to the size of the main casing. Setting the diameter of the inner peripheral portion of the main casing 1 to about 1% or more and 5% or less is important in terms of applying a sufficient share to the inorganic fine particles. Specifically, when the diameter of the inner peripheral part of the main body casing 1 is about 130 mm, the clearance is about 2 mm or more and about 5 mm or less. When the diameter of the inner peripheral part of the main body casing 1 is about 800 mm, the clearance is about 10 mm or more and 30 mm or less. It should be about.

  In the external addition mixing process of the inorganic fine particles in the present invention, the rotating body 2 is rotated by the drive unit 8 using the mixing processing device, and the toner particles and the inorganic fine particles charged in the mixing processing device are stirred and mixed. Inorganic fine particles are externally mixed on the surface of the toner particles.

  As shown in FIG. 3, at least a part of the plurality of stirring members 3 is formed as a feeding stirring member 3 a that sends toner particles and inorganic fine particles in one axial direction of the rotating body as the rotating body 2 rotates. Is done. At least a part of the plurality of stirring members 3 is formed as a return stirring member 3b that returns the toner particles and the inorganic fine particles to the other direction in the axial direction of the rotating body 2 as the rotating body 2 rotates.

  Here, when the raw material inlet 5 and the product outlet 6 are provided at both ends of the main casing 1 as shown in FIG. 2, the direction from the raw material inlet 5 toward the product outlet 6 (in FIG. 2). (Right direction) is called “feed direction”.

  That is, as shown in FIG. 3, the plate surface of the feeding stirring member 3a is inclined so as to feed the toner particles in the feeding direction (13). On the other hand, the plate surface of the stirring member 3b is inclined so as to send toner particles and inorganic fine particles in the return direction (12). Thus, the external addition mixing process of the inorganic fine particles is performed on the surface of the toner particles while repeatedly performing the feed (13) in the “feed direction” and the feed (12) in the “return direction”.

  The stirring members 3a and 3b are a set of a plurality of members arranged at intervals in the circumferential direction of the rotating body 2. In the example shown in FIG. 3, the stirring members 3a and 3b form a pair of two members on the rotating body 2 at an interval of 180 degrees, but three members at an interval of 120 degrees or an interval of 90 degrees. It is good also as a set of many members, such as four sheets. In the example shown in FIG. 3, a total of 12 stirring members 3a and 3b are formed at equal intervals.

  Further, in FIG. 3, D indicates the width of the stirring member, and d indicates the interval indicating the overlapping portion of the stirring member. From the viewpoint of efficiently feeding the toner particles and inorganic fine particles in the feeding direction and the returning direction, it is preferable that D has a width of about 20% to 30% with respect to the length of the rotating body 2 in FIG. In FIG. 3, an example of 23% is shown. Furthermore, it is preferable that the stirring members 3a and 3b have some overlap d between the stirring member 3b and the stirring member when an extension line is drawn in the vertical direction from the end position of the stirring member 3a. Thereby, it is possible to efficiently share the inorganic fine particles which are secondary particles. D is preferably 10% or more and 30% or less in terms of applying a share.

  Regarding the shape of the blade, in addition to the shape shown in FIG. 3, if the toner particles can be fed in the feeding direction and the returning direction and the clearance can be maintained, the shape having a curved surface and the tip blade portion are A paddle structure coupled to the rotating body 2 with a rod-like arm may be used.

  Hereinafter, the present invention will be described in more detail with reference to the schematic views of the apparatus shown in FIGS.

  The apparatus shown in FIG. 2 includes a rotating body 2 having at least a plurality of stirring members 3 installed on the surface, a drive unit 8 that rotationally drives the rotating body 2, and a main body casing that is provided with a gap between the stirring member 3. 1 and a jacket 4 on the inner side of the main body casing 1 and the side surface 10 of the rotating body end, through which a cooling medium can flow.

  Further, the apparatus shown in FIG. 2 discharges the raw material inlet 5 formed in the upper part of the main casing 1 and the externally mixed toner from the main casing 1 in order to introduce toner particles and inorganic fine particles. In addition, a product discharge port 6 formed in the lower part of the main body casing 1 is provided.

  Furthermore, in the apparatus shown in FIG. 2, a raw material inlet inner piece 16 is inserted into the raw material inlet 5, and a product outlet inner piece 17 is inserted into the product outlet 6.

  In the present invention, first, the raw material inlet inner piece 16 is taken out from the raw material inlet 5, and the toner particles are put into the processing space 9 from the raw material inlet 5. Next, inorganic fine particles are introduced into the treatment space 9 from the raw material inlet 5 and the inner piece 16 for raw material inlet is inserted. Next, the rotating body 2 is rotated by the drive unit 8 (11 indicates the direction of rotation), and the processed material introduced above is externally added while being stirred and mixed by a plurality of stirring members 3 provided on the surface of the rotating body 2. Mix.

  The order of charging may be such that the inorganic fine particles are first charged from the raw material charging port 5 and then the toner particles are charged from the raw material charging port 5. Further, after the toner particles and the inorganic fine particles are mixed in advance by a mixer such as a Henschel mixer, the mixture may be supplied from the raw material input port 5 of the apparatus shown in FIG.

  More specifically, controlling the power of the drive unit 8 to 0.2 W / g or more and 2.0 W / g or less as the external additive mixing processing condition, the covering ratio X1 and the diffusion index defined in the present invention are It is preferable in obtaining. Moreover, it is more preferable to control the power of the drive unit 8 to 0.6 W / g or more and 1.6 W / g or less. When the power is lower than 0.2 W / g, the coverage X1 is difficult to increase and the diffusion index tends to be too low. On the other hand, when it is higher than 2.0 W / g, the diffusion index increases, but the inorganic fine particles tend to be embedded too much.

  Although it does not specifically limit as processing time, Preferably it is 3 to 10 minutes. When the treatment time is shorter than 3 minutes, the coverage X1 and the diffusion index tend to be low.

The number of rotations of the stirring member at the time of external mixing is not particularly limited, but the shape of the stirring member 3 in the apparatus in which the volume of the processing space 9 of the apparatus shown in FIG. 2 is 2.0 × 10 ⁻³ m ³ is shown in FIG. The rotation speed of the stirring member when it is made is preferably 800 rpm or more and 3000 rpm or less. By being 800 rpm or more and 3000 rpm or less, it becomes easy to obtain the coverage X1 and the diffusion index defined in the present invention.

  Further, in the present invention, a particularly preferable processing method is to have a pre-mixing step before the external addition mixing processing operation. By including the pre-mixing step, the inorganic fine particles are highly uniformly dispersed on the surface of the toner particles, so that the coverage X1 is likely to increase and the diffusion index is likely to be increased.

  More specifically, as premixing processing conditions, the power of the drive unit 8 is set to 0.06 W / g or more and 0.20 W / g or less, and the processing time is set to 0.5 minutes or more and 1.5 minutes or less. preferable. If the load power is lower than 0.06 W / g or the processing time is shorter than 0.5 minutes as the premixing processing condition, sufficient uniform mixing is difficult to perform as premixing. On the other hand, if the load power is higher than 0.20 W / g or the processing time is longer than 1.5 minutes as the pre-mixing processing condition, the inorganic fine particles are fixed on the surface of the toner particles before sufficient uniform mixing is performed. It may be done.

Regarding the rotation speed of the stirring member in the pre-mixing process, when the volume of the processing space 9 of the apparatus shown in FIG. 2 is 2.0 × 10 ⁻³ m ³ and the shape of the stirring member 3 is as shown in FIG. The rotation speed of the stirring member is preferably 50 rpm or more and 500 rpm or less. By being 50 rpm or more and 500 rpm or less, it becomes easy to obtain the coverage X1 and the diffusion index defined in the present invention.

  After completion of the external addition mixing process, the product discharge port inner piece 17 is taken out from the product discharge port 6, the rotating body 2 is rotated by the drive unit 8, and the toner is discharged from the product discharge port 6. From the obtained toner, coarse particles and the like are separated by a sieve such as a circular vibration sieve as necessary to obtain a toner.

  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.

<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).

<Measuring method of average circularity of toner particles>
The average circularity of the toner particles is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  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 in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the 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. The analysis particle size is measured under the measurement and analysis conditions when the calibration certificate is received, except that the equivalent circle diameter is limited to 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.

<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

<Measurement of residual carbon amount derived from silane compound after washing magnetic substance with styrene>
The measurement of the residual carbon amount derived from the silane compound after washing the magnetic material with styrene is performed according to the following procedure.

  A glass vial with a capacity of 50 ml is charged with 20 g of styrene and 1.0 g of a magnetic material, 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 treating agent in the magnetic material into styrene. Thereafter, the magnetic material and styrene are separated and sufficiently dried in a vacuum dryer. And the carbon amount per unit mass is measured in HORIBA carbon-sulfur analyzer EMIA-320V. By this operation, the obtained carbon amount is defined as the residual carbon amount derived from the silane compound after the magnetic material is washed with styrene. 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 of measuring the amount of silicon present on and around the magnetic iron oxide surface>
In the present invention, the amount of silicon present on and around the magnetic iron oxide surface is determined by the following procedure.

First, the dissolution rate of the iron element 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 amount of silicon is determined and used as the amount of silicon present on and around the magnetic iron oxide surface (surface silicon amount of magnetic iron oxide).

<Measurement method of volumetric specific heat of inorganic fine particles>
The volume specific heat of the inorganic fine particles in the present invention was calculated from the product of both values obtained from specific heat (J / g · ° C.) and true density (g / cm ³ ).

  For measurement of specific heat, measurement was performed in StepScan mode using an input-compensated differential scanning calorimeter DSC8500 manufactured by TA Instruments. The sample used was an aluminum pan and an empty pan was used as a control. The sample was allowed to stand isothermally at 20 ° C. for 1 minute, then heated to 100 ° C. at 10 ° C./min, and the specific heat at 80 ° C. was calculated.

  The true density was measured with a dry automatic density meter Accupic 1330 manufactured by Shimadzu Corporation.

  The following procedure was used to isolate the inorganic fine particles from the toner. First, the number of “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for cleaning a precision measuring instrument having a pH of 7 comprising an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) Ultrasonically disperse in ion-exchanged water added dropwise and let stand for 24 hours. The inorganic fine particles can be isolated by collecting and drying the supernatant. When a plurality of external additives are externally added to the toner, the supernatant can be separated and isolated by a centrifugal separation method for the purpose of obtaining target inorganic fine particles.

<Measurement method of carbon oil-based immobilization rate of inorganic fine particles>
(Extraction of free silicone oil)
(1) Place 0.50 g of inorganic fine particles and 40 ml of chloroform in a beaker and stir for 2 hours.
(2) Stop stirring and let stand for 12 hours.
(3) The sample is filtered and washed three times with 40 ml of chloroform.

(Measurement of carbon content)
The sample is burned at 1100 ° C. in an oxygen stream, and the amount of generated CO and CO ₂ is measured by IR absorbance to measure the amount of carbon in the sample. The carbon amount before and after extraction of the silicone oil is compared, and the immobilization rate based on the carbon amount of the silicone oil is calculated as follows.

  (1) Place 0.40 g of sample in a cylindrical mold and press.

  (2) 0.15 g of the pressed sample is precisely weighed, placed on a combustion board, and measured with Horiba EMA-110.

  (3) [Carbon amount after silicone oil extraction] / [Carbon amount before silicone oil extraction] × 100 is defined as the immobilization rate based on the carbon amount of silicone oil.

  In addition, when the surface treatment with silicone oil is performed after the hydrophobic treatment with alkoxysilane or silazane, the amount of carbon in the sample is measured after the hydrophobic treatment with alkoxysilane or silazane. Are compared, and the immobilization rate based on the amount of carbon derived from silicone oil is calculated as follows.

  (4) [Carbon amount after silicone oil extraction-carbon amount of sample after hydrophobic treatment with alkoxysilane or silazane] / [(carbon amount before silicone oil extraction-carbon amount of sample after hydrophobic treatment with alkoxysilane or silazane) )] × 100 is defined as the carbon oil-based immobilization rate of silicone oil.

  On the other hand, when the surface treatment with silicone oil is performed with a hydrophobic treatment with alkoxysilane or silazane, using the sample after the hydrophobic treatment with silicone oil, the fixation rate based on the amount of carbon derived from silicone oil is as follows: calculate.

  (5) [(Carbon amount after silicone oil extraction of sample after surface treatment with silicone oil)] / [Carbon amount before extraction of sample after surface treatment with silicone oil] × 100, The immobilization rate.

<Measurement method of coverage X1>
The coverage X1 with the inorganic fine particles on the toner surface is calculated as follows.

The following apparatus is used under the following conditions, and elemental analysis of the toner surface is performed.
-Measuring device: Quantum 2000 (trade name, manufactured by ULVAC-PHI Co., Ltd.)
・ X-ray source: Monochrome Al Kα
-Xray Setting: 100 μmφ (25 W (15 KV))
・ Photoelectron extraction angle: 45 degrees ・ Neutralization condition: Combined use of neutralizing gun and ion gun ・ Analysis area: 300 × 200 μm
・ Pass Energy: 58.70eV
・ Step size: 1.25eV
・ Analysis software: Maltipak (PHI)

  The obtained quantitative value of the element derived from the inorganic fine particles is Y1.

  Next, the single inorganic fine particles used externally added to the toner particles are measured. The quantitative value of the element derived from the inorganic fine particles of the obtained inorganic fine particles is Y2.

In the present invention, the coverage with inorganic fine particles on the toner surface is defined as follows.
Inorganic fine particle coverage X1 (area%) = Y1 / Y2 × 100

  In order to improve the accuracy of this measurement, it is preferable to measure Y1 and Y2 twice or more.

<Quantitative determination method of inorganic fine particles in toner>
(1) Determination of the content of inorganic fine particles in the toner (standard addition method)
The following method describes the case where the inorganic fine particles are silica fine particles. When the inorganic fine particles are other than silica fine particles, the content of the inorganic fine particles can be quantified in the same manner as described below for the metal element derived from the inorganic fine particles.

  3 g of toner is put in an aluminum ring having a diameter of 30 mm, and pellets are produced at a pressure of 10 tons. Then, the intensity of silicon (Si) is obtained by wavelength dispersive X-ray fluorescence analysis (XRF) (Si intensity-1). The measurement conditions may be those optimized by the XRF apparatus to be used, but all the series of intensity measurements are performed under the same conditions. To the toner, silica fine particles having a primary particle number average particle diameter of 12 nm are added in an amount of 1.0 mass% with respect to the toner, and then mixed by a coffee mill.

  After mixing, after pelletizing in the same manner as described above, the strength of Si is obtained in the same manner as described above (Si strength -2). The same operation is performed to obtain Si strength (Si strength-3, Si strength-4) in a sample in which silica fine particles are added and mixed at 2.0 mass% and 3.0 mass% with respect to the toner. The silica content (mass%) in the toner is calculated by the standard addition method using Si strengths −1 to 4.

(2) Separation of silica fine particles from toner When the toner contains a magnetic substance, the silica fine particles are quantified through the following steps.

  5 g of toner is weighed into a 200 ml polycup with a lid using a precision balance, 100 ml of methanol is added, and the mixture is dispersed for 5 minutes with an ultrasonic disperser. Attract the toner with a neodymium magnet and discard the supernatant. After repeating the operation with methanol and discarding the supernatant three times, 100 ml of 10% NaOH and “Contaminone N” (non-ionic surfactant, anionic surfactant, organic builder pH7 precision measuring instrument washing A few drops of a 10% by weight aqueous neutral detergent solution (manufactured by Wako Pure Chemical Industries, Ltd.) are added and mixed gently, and then allowed to stand for 24 hours. Then, it isolate | separates again using a neodymium magnet. At this time, rinse with distilled water repeatedly so that NaOH does not remain. The collected particles are sufficiently dried by a vacuum dryer to obtain particles A. By the above operation, the externally added silica fine particles are dissolved and removed.

(3) Measurement of Si intensity in particle A 3 g of particle A is put in an aluminum ring having a diameter of 30 mm, a pellet is prepared at a pressure of 10 tons, and the intensity of Si is obtained by wavelength dispersive X-ray fluorescence analysis (XRF). (Si strength -5). The silica content (mass%) in the particles A is calculated using Si strength -5 and Si strength -1 to 4 used in the determination of the silica content in the toner.

(4) Separation of magnetic material from toner To 5 g of particles A, 100 ml of tetrahydrofuran is added and mixed well, followed by ultrasonic dispersion for 10 minutes. Attract magnetic particles with a magnet and discard the supernatant. This operation is repeated 5 times to obtain particles B. By this operation, organic components such as resin other than the magnetic substance can be almost removed. However, since there is a possibility that the insoluble content of tetrahydrofuran in the resin may remain, it is preferable to burn the remaining organic component by heating the particle B obtained by the above operation to 800 ° C., and the particle obtained after the heating. C can be approximated to the magnetic material contained in the toner.

By measuring the mass of the particles C, the magnetic substance content W (% by mass) in the toner can be obtained. At this time, the mass of the particles C is multiplied by 0.9666 (Fe ₂ O ₃ → Fe ₃ O ₄ ) in order to correct the increased amount of oxidation of the magnetic material.

By substituting each quantitative value into the following equation, the amount of silica particles added externally is calculated.
Externally added silica fine particle content (mass%) = silica content in toner (mass%) − silica content in particles A (mass%)

<Measurement method of true specific gravity of toner and inorganic fine particles>
The true specific gravity of the toner and inorganic fine particles was measured with a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). The conditions are as follows.

Cell: SM cell (10 ml)
Sample amount: 2.0 g (toner), 0.05 g (inorganic fine particles)
This measurement method measures the true specific gravity 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.

<Measurement of Glass Transition Point (Tg) of Toner Particle>
In the present invention, the toner particle Tg is measured by the following procedure using a differential scanning calorimeter (DSC).

  As DSC to be used, it measures according to ASTM D3418-82, for example using "Q1000" (made by TA Instruments). The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, about 2 mg of the sample toner is precisely weighed and placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed in the following sequence.

<Measurement conditions>
• Equilibrate at 20 ° C for 5 minutes.
・ Modulation of 1.0 ° C / min is applied, and the temperature is increased to 140 ° C at 1 ° C / min.
• Equilibrate at 140 ° C for 5 minutes.
-Lower the temperature to 20 ° C.

  The glass transition temperature (Tg) here is determined by the midpoint method.

  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.

<Example of production of magnetic iron oxide 1>
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 of magnetic iron oxide 2>
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 of magnetic iron oxide 3>
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.

<Example of production of magnetic iron oxide 4>
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.

<Example of production of magnetic iron oxide 5>
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 of comparative magnetic iron oxide 1>
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 of comparative magnetic iron oxide 2>
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. Then, it pulverized and obtained the magnetic body 1 through the sieve with an opening of 100 micrometers. The physical properties of the magnetic body 1 are shown in Table 2.

<Manufacture of magnetic bodies 2-10>
In the production of the 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 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 particle surface of the comparative magnetic iron oxide 2 is coated with a silane coupling agent, and volatile components such as methanol are vaporized to form a decyl group on the surface. A comparative magnetic body 3 was obtained. Table 2 shows the physical properties of the obtained magnetic substance.

<Production example of comparative magnetic body 4>
During an aqueous ferrous sulfate solution, 1.10 eq of sodium hydroxide solution from 1.00 relative to iron element, the amount of P ₂ O ₅ to an iron element to be 0.15% by mass in terms of phosphorus, the iron element On the other hand, SiO ₂ in an amount of 0.50% by mass in terms of silicon element was mixed to prepare an aqueous solution containing ferrous hydroxide. The pH of the aqueous solution was 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.

  Subsequently, after adding ferrous sulfate aqueous solution so that it may become 0.90 to 1.20 equivalent with respect to the original alkali amount (sodium component of caustic soda) to this slurry liquid, the slurry liquid is maintained at pH 7.6, The oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide. After filtration and washing, the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured. Next, this water-containing sample is put into another aqueous medium without being dried, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid is adjusted to about 4.8. Then, 1.6 parts of n-hexyltrimethoxysilane coupling agent was added to 100 parts of magnetic iron oxide with stirring (the amount of magnetic iron oxide was calculated as a value obtained by subtracting the water content from the water-containing sample), and water was added. Decomposition was performed. Thereafter, the mixture was sufficiently stirred, and the dispersion was subjected to surface treatment at a pH of 8.6. The produced hydrophobic magnetic material was filtered with a filter press, washed with a large amount of water, and then dried at 100 ° C. for 15 minutes and at 90 ° C. for 30 minutes to obtain a comparative magnetic material 4. Table 2 shows the physical properties of the obtained magnetic substance.

<Method for Producing Toner Particle 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 3.0 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.)
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. The toner particles 1 had a glass transition temperature Tg of 52 ° C.

<Production of toner particles 2 to 17>
In the production of the toner particles 1, toner particles 2 to 17 were obtained in the same manner as in the production of the toner 1 except that the type and amount of the magnetic material were changed as shown in Table 3. Table 3 shows the physical properties of the obtained toner particles.

<Manufacture of toner particles 18>
450 parts of 0.1M Na ₃ PO ₄ aqueous solution is added to 720 parts of ion-exchanged water and heated to 60 ° C., and then 67.7 parts of 1.0M CaCl ₂ aqueous solution is added to contain a dispersion stabilizer. An aqueous medium was obtained.
-Styrene 79.0 parts-N-butyl acrylate 21.0 parts-Divinylbenzene 0.6 parts-Iron complex of monoazo dye (T-77: manufactured by Hodogaya Chemical Co., Ltd.) 3.0 parts- Comparative magnetic material 4 90. 0 parts styrene-acrylic resin (peak molecular weight = 10000, glass transition point: 74 ° C., acid value = 10 mg / KOH) 5.0 parts The above formulation is uniformly applied using an attritor (Mitsui Miike Chemical Co., Ltd.) A monomer composition was obtained by dispersing and mixing. This monomer composition was heated to 60 ° C., and 15.0 parts of Fischer-Tropsch wax was added and mixed therein. After dissolution, 7.0 parts of dilauroyl peroxide was dissolved as a polymerization initiator.

The monomer composition was charged into the aqueous medium, and the mixture was granulated by stirring at 12,000 rpm for 10 minutes with a TK homomixer (Special Machine Industries Co., Ltd.) in an N2 atmosphere at 60 ° C.
Thereafter, the mixture was reacted at 74 ° 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 18. The toner particles 18 had a glass transition temperature Tg of 52 ° C. Table 3 summarizes the physical properties of the toner particles obtained.

<Production of Example Toner 1>
The toner particles 1 were externally mixed using the apparatus shown in FIG.

In the present embodiment, a device in which the diameter of the inner peripheral portion of the main casing 1 is 130 mm and the volume of the processing space 9 is 2.0 × 10 ⁻³ m ³ is used, and the rated power of the drive unit 8 is 5.5 kW. The shape of the stirring member 3 was the same as that shown in FIG. The overlapping width d of the stirring member 3a and the stirring member 3b in FIG. 3 is 0.25D with respect to the maximum width D of the stirring member 3, and the clearance between the stirring member 3 and the inner periphery of the main casing 1 is 3.0 mm. .

In the above-described apparatus configuration, 100 parts of the toner particles 1 and silica fine particles 1 shown in Table 4 (silica fine particles obtained by treating a silica fine particle base of the original BET 300 m ² / g with 25 parts of silicone oil and then treating with hexamethyldisilazane, The silicone oil immobilization rate was 99%, and the volume specific heat was 6000 J / (cm ³ · K)) 0.60 part.

  After the toner particles 1 and the silica fine particles 1 were added, premixing was performed in order to uniformly mix the toner particles and the silica fine particles. The premixing conditions were such that the power of the drive unit 8 was 0.10 W / g (the rotational speed of the drive unit 8 was 150 rpm) and the processing time was 1 minute.

  After the pre-mixing, an external additive mixing process was performed. The external mixing process conditions are such that the peripheral speed of the outermost end of the stirring member 3 is adjusted so that the power of the drive unit 8 is constant at 0.60 W / g (the rotational speed of the drive unit 8 is 1400 rpm), and the processing time For 5 minutes.

  After the external addition and mixing treatment, coarse particles and the like were removed with a circular vibration sieve equipped with a screen having a diameter of 500 mm and an opening of 75 μm, to obtain Example Toner 1. The obtained toner was analyzed and found to contain 100 parts of a binder resin. Table 5 shows the physical properties of Toner 1 for Example.

<Production of Toners for Examples 2-20, 22-24, and Toners for Comparative Examples 1-4>
In the production of the toner for example 1, the toner particles used, the kind of silica fine particles, and the number of parts of the silica fine particles were changed as shown in Table 5 in the same manner as in the production of the toner 1 for the examples. Toners 2 to 20, 22 to 24, and comparative toners 1 to 4 were obtained. The obtained toner was analyzed and found to contain 100 parts of a binder resin. Table 5 shows the physical properties of the obtained toner.

<Manufacture of Example Toner 21>
100 parts of toner particles 1 and 1.0 part of silica fine particles 1 were externally mixed for 4 minutes at 4000 rpm using a Henschel mixer 10C (Mitsui Miike Chemical Co., Ltd.). After the external addition and mixing treatment, coarse particles and the like were removed with a circular vibrating sieve equipped with a screen having a diameter of 500 mm and an opening of 75 μm, whereby Toner 21 for Example was obtained. The obtained toner was analyzed and found to contain 100 parts of a binder resin. Table 5 shows the physical properties of Toner 21 for Example.

<Manufacture of Toners 5-8 for Comparative Examples>
In the production of the toner 21 for the example, a comparative example was made in the same manner as in the production of the toner 21 for the example except that the toner particles to be used, the type of silica fine particles, and the number of silica fine particles were changed as shown in Table 5. Toners 5 to 8 were obtained. The obtained toner was analyzed and found to contain 100 parts of a binder resin. Table 5 summarizes the physical properties of the obtained toner.

<Manufacture of Toner 9 for Comparative Example>
(Manufacture of fatty acid metal salts)
A container with a stirrer was prepared, and the stirrer was rotated at 350 rpm. 500 parts of a 0.7% by weight sodium stearate aqueous solution was added to the receiving container, and the liquid temperature was adjusted to 85 ° C. Next, 525 parts of a 0.4 mass% zinc sulfate aqueous solution was dropped into the receiving container over 15 minutes. After the completion of charging the whole amount, the reaction was terminated by aging for 10 minutes at the temperature during the reaction.

Next, the fatty acid metal salt slurry thus obtained was washed by filtration. The obtained washed fatty acid metal salt cake was roughly crushed and then dried at 105 ° C. using a continuous instantaneous air dryer. Then, after pulverizing with a nano grinding mill [NJ-300] (manufactured by Sanrex) under conditions of an air volume of 4.0 m ³ / min and a processing speed of 40 kg / h, reslurry and fine particles using a wet centrifugal classifier The coarse particles were removed. Then, it dried at 80 degreeC using the continuous instantaneous airflow dryer, and obtained the fatty acid metal salt.

(External additive processing)
100 parts of toner particles 18, 1.0 part of silica fine particles 1, 0.50 parts of fatty acid metal salt, and Henschel mixer 10C (Mitsui Miike Chemical Co., Ltd.) were charged. Then, the peripheral speed of the stirring blade was 40 m / sec, and stirring and mixing were performed for 4 minutes. Thereafter, stirring / mixing was stopped for 1 minute, and the peripheral speed of the stirring blade was set to 40 m / sec, followed by stirring / mixing for 4 minutes to obtain a comparative toner 9 having a weight average particle diameter (D4) of 6.8 μm. . The obtained toner was analyzed and found to contain 100 parts of a binder resin. Table 5 summarizes the physical properties of the obtained toner.

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

(Preservation 1)
5 g of toner is placed in a thermostat adjusted to a temperature of 21 ° C. and a humidity of 90%, and an aging treatment is performed for 24 hours. Thereafter, the temperature is raised at a rate of 3.0 ° C. per hour and adjusted to 57 ° C. and 90% over 12 hours. In this state, after allowing to stand for 72 hours, the temperature is lowered at a rate of 3.0 ° C. per hour to return to 21 ° C. and 90% (FIG. 4).

The degree of aggregation of the toner after passing through this cycle 1 and the degree of toner before passing through the cycle 1 are measured, respectively, and the rate of increase in the degree of aggregation of storage stability 1 is obtained from the following equation.
Aggregation degree increase rate of storage stability 1 (%) = (aggregation degree of toner after cycle 1) / (aggregation degree of toner before going through cycle 1 × 100)

  Evaluation of preservability 1 is performed using this rate of increase in aggregation. A lower aggregation rate indicates a toner with better storage stability.

  The increase rate of aggregation degree of storage stability 1 was measured using the toner for example 1, and it was 113%. The evaluation results of Example Toner 1 are shown in Table 6.

(Preservation 2)
5 g of toner is placed in a thermostat adjusted to a temperature of 21 ° C. and a humidity of 90%, and an aging treatment is performed for 24 hours. Thereafter, the temperature is raised at a rate of 12 ° C. per hour, and adjusted to 57 ° C. and 90% over 3 hours.

In this state, after holding for 3 hours, the temperature is lowered at a pace of 12 ° C. and returned to 57 ° C. and 90%. And after hold | maintaining for 3 hours, it heats up again. In this way, the temperature was raised and lowered seven times as shown in FIG. 5 at a temperature and humidity of 21 ° C. 90% and 57 ° C. 90%. The degree of aggregation of the toner after the cycle 2 and the toner before the cycle 2 are respectively measured, and the aggregation degree increase rate of the storage stability 2 is obtained from the following formula.
Aggregation degree increase rate of storage stability 2 (%) = (aggregation degree of toner after cycle 2) / (aggregation degree of toner before going through cycle 2 × 100)

  The preservability 2 is evaluated using this rate of increase in aggregation. A lower aggregation rate indicates a toner with better storage stability.

  In storability 2, the temperature rise rate is increased more than in storability 1, and the toner easily melts and agglomerates in response to a rapid heat change. On the other hand, by repeating the temperature increase / decrease, the easily meltable components inside the toner gradually gather on the toner surface, and the toner is likely to aggregate during the temperature increase or during holding at 57 ° C. For this reason, the evaluation method that repeats the temperature increase / decrease of the storability 2 is a more strict evaluation of the storability of the toner (harsh environment evaluation) than the evaluation method of maintaining the storability 2 at a constant temperature. .

  The aggregation degree increase rate of storage stability 2 was measured using toner 1 for the example and found to be 121%. The evaluation results of Example Toner 1 are shown in Table 6.

  The degree of aggregation is measured according to the following procedure.

As the measuring apparatus, a “powder tester” (manufactured by Hosokawa Micron Co., Ltd.) having a vibration table side surface portion connected with a digital display vibrometer “Digivibro MODEL 1332A” (manufactured by Showa Keiki Co., Ltd.) was used. Then, a sieve having a mesh size of 38 μm (400 mesh), a sieve having a mesh size of 75 μm (200 mesh), and a sieve having a mesh size of 150 μm (100 mesh) were stacked in this order on the vibrating table of the powder tester. The measurement was performed as follows in an environment of 23 ° C. and 60% RH.
(1) The vibration width of the vibration table was adjusted in advance so that the displacement value of the digital display vibrometer was 0.30 mm (peak-to-peak).
(2) 5 g of toner that had been allowed to stand for 24 hours in an environment of 23 ° C. and 60% RH was precisely weighed and gently placed on a sieve having an opening of 150 μm.
(3) After vibrating the sieve for 15 seconds, the mass of the toner remaining on each sieve was measured, and the degree of aggregation was calculated based on the following equation.
Aggregation degree (%) = {(sample mass (g) on a sieve having an opening of 150 μm) / 5 (g)} × 100
+ {(Sample mass on a sieve having an opening of 75 μm (g)) / 5 (g)} × 100 × 0.6
+ {(Sample mass (g) on a sieve having an opening of 38 μm) / 5 (g)} × 100 × 0.2

(Durability evaluation)
The following evaluation was performed using the toner 1 for Example.

As the image forming apparatus, a commercially available LaserJet P2055 (manufactured by Hewlett Packard) was used, the developing sleeve diameter was changed to 10 mm, and the printing speed was changed from 35 sheets / minute to 40 sheets / minute. Thereby, it is possible to perform a strict evaluation that the deterioration of the toner is promoted and the developability of the toner is also lowered. The paper type used was A4 color laser copy paper (manufactured by Canon, 80 g / m ² ).

  The evaluation environment is a high temperature and high humidity (33 ° C / 80%) environment, which is disadvantageous for toner deterioration and charging failure, and an intermittent durability test (intermittent 2 sheets for 4 seconds, 1.5% printing rate, 10,000 durable sheets) is performed. The solid black density at the initial stage and after the endurance was measured. By setting the printing rate to 1.5%, the toner can be evaluated more severely.

  Although the above evaluation was performed using the toner 1 for Example, the solid black density was good both in the initial stage of durability and after the endurance. The evaluation results of Example Toner 1 are shown in Table 6.

(Fixability evaluation)
The toner fixability is evaluated according to the following procedure.

Evaluation was performed in an environment of 23 ° C. and 50% RH. For fixing media, FOX RIVER BOND paper (90 g / m ² ) was used. By using a medium having relatively large surface irregularities, the fixability can be strictly evaluated by making it easy to rub.

In the evaluation procedure, the image density (measured using a Macbeth reflection densitometer (manufactured by Macbeth Co., Ltd.)) was set to 0.75 or more on a FOX River Bond paper at a set temperature of 165 ° C. from a state where the entire fixing device was cooled to room temperature. The halftone image density is adjusted so as to be 0.80 or less, and image output is performed. Thereafter, the halftone fixed image was rubbed 10 times with a Sylbon paper to which a load of 55 g / cm ² was applied. From the halftone image density before and after rubbing, the rubbing density reduction rate at 170 ° C. was calculated using the following formula. Fixability evaluation is performed using the rub density reduction rate. The lower the rub density reduction rate, the better the fixability.

  When the above-described fixability evaluation was performed using the toner 1 for Example, the rubbing density reduction rate was as good as 0.10%. The evaluation results of Example Toner 1 are shown in Table 6.

<Examples 2 to 24 and Comparative Examples 1 to 9>
Using the toners for examples 2 to 24 and the toners for comparative examples 1 to 9, storage stability 1, storage stability 2, durability evaluation, and fixing performance evaluation were performed. The evaluation results are shown in Table 6.

  1: main body casing, 2: rotating body, 3, 3a, 3b: stirring member, 4: jacket, 5: raw material inlet, 6: product outlet, 7: central shaft, 8: drive unit, 9: processing space, 10: Rotating body end side surface, 11: Rotating direction, 12: Return direction, 13: Feeding direction, 16: Inner piece for raw material inlet, 17: Inner piece for product outlet, d: Overlapping portion of stirring member Interval, D: Width of stirring member, 100: Electrostatic latent image carrier (photoconductor), 102: Toner carrier, 103: Development 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, 14 : Stirring member

Claims (7)

A toner having toner particles containing a binder resin and a colorant, and inorganic fine particles,
The thermal conductivity of the toner is 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
Ri surface free energy 30.0mJ / m ² or more 50.0mJ / m ² or less der of the toner,
The colorant, toner, wherein the processing magnetic der Rukoto surface treated with a silane compound magnetic iron oxide. 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 is the magnetic iron oxide. The toner according to claim 1 , wherein the toner content is 0.05% by mass or more and 0.50% by mass or less based on the toner. The residual carbon amount derived from the silane compound after washing the treated magnetic body with styrene is 0.40% by mass or more and 1.20% by mass or less based on the magnetic iron oxide. The toner according to 1 or 2 . The inorganic fine particles, the toner according to any one of claim 1 to 3, characterized in that it is surface-treated with silicone oil. The toner according to claim 4 , wherein an immobilization ratio of the inorganic fine particles to the silicone oil is 85% by mass or more. The inorganic fine particles, the toner according to claim 4 or 5, characterized in that after applying the treatment with silicone oil, an inorganic fine particles having been subjected to treatment with alkoxysilane or silazanes. The volume specific heat at 50 ° C. of the inorganic fine particles, the toner according to any one of claim 1 to 6, characterized in that at 5000J / (cm ³ · K) or more 10000J / (cm ³ · K) or less .

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