JP2020095098A - toner - Google Patents

Abstract

To provide toner excellent in anti-blocking property, storage stability, antistatic property, fluidity, and non-aggregation property by reducing generation of aggregation of silica as an external additive and suppressing separation of external additives from a toner surface.SOLUTION: The toner includes toner particles and an external additive. The external additive contains (i) silica particles having a number average particle diameter of primary particles of 40 nm or more and 200 nm or less, and (ii) inorganic particles having a number average particle size of primary particles of 10 nm or more and 90 nm or less and having rectangular solids or cubes. Defining the number average particle diameter of the silica particles is DA, and the number average particle diameter of the inorganic particles is DB, the relationship of DA-DB>0 is satisfied.SELECTED DRAWING: None

Description

The present invention relates to toner used in electrophotographic systems, electrostatic recording systems, electrostatic printing systems, and toner jet systems.

As copiers and printers have become widespread, the performance required for toner has become higher. In recent years, a digital printing technique called print on demand (POD) that directly prints without a plate-making process has been receiving attention. This print-on-demand (POD) has an advantage over the conventional offset printing because it can support small lot printing, printing with variable contents for each sheet (variable printing), and distributed printing. Considering the application of the image forming method using toner to the POD market, it is required to stably obtain a print product with high image quality even when outputting a large amount at high speed for a long period of time. Be done.
So far, particles with a relatively large particle size have been added to the toner for the purpose of maintaining stable performance over a long period of time, resulting in excellent blocking resistance, storage stability, chargeability, fluidity, cohesion, etc. Many suggestions have been made.
Patent Document 1 proposes that the atypical silica particles formed by the sol-gel method are added to the toner particle main body to maintain the fluidity of the resin particle main body, and the toner particles have a specific surface area of 10.0 m ² / There has been proposed a toner in which fog on a non-image area is suppressed by adding silica particles of g or more and 50.0 m ² /g or less and performing surface treatment with heat. Patent Document 2 proposes a toner in which non-spherical silica particles are added to toner particles to improve transferability and suppress image defects. Patent Document 3 proposes a developer in which fine particles of a silicon compound are added to toner particles to improve fluidity, cleaning property, and stable charging property. Further, strontium titanate is added, and in addition to the above-mentioned auxiliary effect, the effect of polishing and removing the deposits on the internal parts of the apparatus is obtained.

JP, 2012-163623, A JP, 2013-190646, A Patent 4875850

However, silicon compound fine particles having a relatively large particle size, which can give a spacer effect to the toner, are surface-treated with a high-viscosity siloxane to be dispersed, but agglomeration occurs and detachment from the resin of the toner base occurs. Therefore, there is room for improvement in charging stability and fluidity depending on the usage conditions, and further improvement of the toner is required.
When the strontium titanate has a cubic shape and a particle size larger than that of the silicon compound, the strontium titanate is more likely to be released as a toner outermost shell by coming into contact with the flow path and the toner.
Therefore, the chargeability is lowered and localization occurs. Attempts have been made to embed these particles in the toner resin matrix in order to prevent them from being detached, but unfortunately the chargeability is reduced, the function as a spacer is reduced, and the effect on fluidity is halved. I have not been able to show it.
The object of the present invention is to make the external additive adhere more uniformly and strongly to the toner surface while maintaining the toner fluidity, the polishing effect and the protection of parts, and also to generate the agglomerates of silica particles and the external surface from the toner surface. It is to provide a toner excellent in blocking resistance, storage stability, charging property, fluidity and non-aggregating property by reducing the detachment of the additive.

The above problems can be solved by a toner having the following configuration.
.. That is, the present invention is a toner containing toner particles and an external additive,
The external additives include (i) silica particles having a number average particle size of primary particles of 40 nm or more and 200 nm or less, and (ii) a number average particle size of primary particles of 10 nm or more and 90 nm or less, and an inorganic material having a rectangular parallelepiped or a cube. Particles and
When the number average particle diameter of the silica particles is DA and the number average particle diameter of the inorganic particles is DB,
DA-DB>0
The present invention relates to a toner that satisfies the relationship of

The external additive adheres to the toner surface more uniformly and strongly than before, while maintaining the toner fluidity, the polishing effect and the protection of parts. Further, the generation of aggregates of silica particles is reduced, and the detachment of the external additive from the toner surface is reduced. From the above, it is possible to provide a toner excellent in blocking resistance, storage stability, chargeability, fluidity, and non-aggregating property.

It is a figure which shows the concrete model of the two-dimensional structure of the inorganic particle which has a rectangular parallelepiped or a cube, and silica. It is a figure which shows the observation image by the electron microscope of the two-dimensional structure of the inorganic particle which has a rectangular parallelepiped or a cube, and silica.

Hereinafter, modes for carrying out the present invention will be described in detail.

The present invention provides a toner containing toner particles and an external additive,
The external additive has (i) silica particles having a number average particle size of primary particles of 40 nm or more and 200 nm or less, and (ii) a number average particle size of primary particles of 10 nm or more and 90 nm or less, and has a rectangular parallelepiped or a cube. When the number average particle diameter of the silica particles is DA and the number average particle diameter of the inorganic particles is DB, the relationship of DA-DB>0 is satisfied.

By using the toner of the present invention as described above, the detachment of the external additive, which is the above-mentioned problem, is reduced, so that the chargeability and fluidity can be more stabilized.

The present inventors presume the mechanism of this action and effect by using the toner of the present invention as follows.

Silicon oxide (silica) particles with a large particle size are advantageous for embedding in durability, have a high spacer effect because they always form the outermost shell of the toner, and have a high charge retention property. Easily desorbed by internal circulation. For this reason, when the toners are compared with each other in the initial stage and the passage of time, deterioration of chargeability and localization due to desorption of the external additive become apparent and the quality of the output image deteriorates. To solve this problem, by using silica and inorganic particles having a rectangular parallelepiped or a cube having a particle size smaller than that of silica, a two-dimensional structure of silica-cuboids or inorganic particles having a cubic is formed. Since it becomes an external additive that comes into contact with the toner base resin at points, it is less likely to be detached from the toner base as compared with an external additive that contacts the family 1 point. As a result, the image quality can be maintained by preventing the deterioration and localization of the charging property caused by the elimination of the external additive. Furthermore, since the spacer effect continues and the fluidity is maintained, it can withstand long-term use.

A configuration for achieving the object in the present invention will be described in detail below.

[Silicon oxide (silica) particles]
The toner of the present invention is characterized by having silicon oxide (silica) particles having a number average diameter of 40 nm or more and 200 nm or less on the toner surface. When the particle size of the silicon compound fine particles is within the above range, the convex portions can be maintained on the toner surface even when a mechanical load is applied in the developing device, the toner charge amount is less likely to decrease, and variations in reflection density and non-uniformity occur. Contributes to the reduction of image area fog.

The silicon oxide particles may be produced by a known production method such as a combustion method or hydrothermal synthesis, but it is preferable because amorphous silica particles produced by the combustion method are less likely to be affected by moisture in the air.

Further, the silica particles are preferably surface-treated with silicone oil. Among them, preferred viscosity of 300 mm ² / s or more 50,000 mm ² / s or less of dimethyl silicone oil, more preferably the viscosity is less than 3000 mm ² / s or more 20000 mm ² / s. This process facilitates the formation of a two-dimensional structure. Further, the silicone oil is preferably contained in the silica particles in an amount of 0.01% by mass or more and 5.00% by mass or less in order to obtain the effect of the present invention, and more preferably 0.1% by mass or more and 5.00% by mass or less. Is.

Further, silica having a large particle size is used in combination with inorganic particles having a rectangular parallelepiped or a cube, which will be described later, in order to suppress desorption of the particles from the toner surface, transfer to another member, or uneven distribution due to movement on the toner surface. It is preferable that the three-dimensional structure is formed and is in contact with the resin on the surface of the toner particles at a plurality of points. In order to allow the inorganic particles having a two-dimensional structure silica-cuboid or cube to be present on the toner surface, it is possible to mix the silicon oxide particles and the inorganic particles having the cube or cube with the toner particles. For the mixing with the toner particles, a known mixer such as a Henschel mixer, a mechano hybrid (manufactured by Nippon Coke Co., Ltd.), a super mixer, and Nobilta (manufactured by Hosokawa Micron) can be used, and the device is not particularly limited.

The addition amount of the silica particles in the present invention is 0.5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the toner particles.

[Inorganic particles having a rectangular parallelepiped or a cube]
Regarding the inorganic particles having a rectangular parallelepiped or a cube with a number average diameter of 10 nm or more and 90 nm or less according to the present invention, the particle diameter is within this range to form a two-dimensional structure with silica of 40 nm or more and 200 nm or less. Since the structure comes into contact with the toner surface at a plurality of points, it is difficult to be detached from the toner surface, and it becomes an external additive having a spacer effect and a charge assisting property. A specific model of this two-dimensional structure is shown in FIG. 1, and an image observed with an electron microscope is shown in FIG. In FIG. 1, for one inorganic particle 102, the model formed by one silica 101 is M1, and the model formed by two silica 101 is M2-1, M2-2, and three. The model formed with silica 101 is M3. Further, in FIG. 2, the observed image P1 corresponds to M1 in FIG. 1, the observed image P2-1 corresponds to M2-1 in FIG. 1, and the observed image P3 corresponds to M3 in FIG. 1, respectively. Is obtained by observing the toner surface in Examples described later.

In addition, as described above, with respect to the silica particles, the inorganic particles having the rectangular parallelepiped or the cube are required to have a small particle size, and the number average particle diameter of the silica particles is DA, and the average particle of the inorganic particles having the rectangular parallelepiped or the cube. When the diameter is DB,
DA-DB>0
And preferably satisfies DA-DB>5 nm
Is.

Examples of the inorganic particles having a rectangular parallelepiped or a cube used in the present invention include strontium titanate, barium titanate, and cerium oxide, and strontium titanate particles are preferable. The surface of the rectangular parallelepiped or cube may be surface-treated with a fatty acid or a metal salt thereof, silicone oil, a silane coupling agent, a titanium coupling agent, or the like. It is preferable in that the environmental stability of the charging property and the durability stability in a high temperature and high humidity environment can be improved.

The content of the inorganic particles having the rectangular parallelepiped or the cube in the toner is 0.02 times or more and 5.00 times or less the content of silica in the toner in order to assist the charging of silica particles having a large particle size. preferable. If it is more than 5 times, the charge maintainability of silica having a large particle size becomes difficult to be exhibited.

The production of strontium titanate particles used as the inorganic particles having a rectangular parallelepiped or a cube according to the present invention will be described. One of the manufacturing methods is an atmospheric heating reaction method. At this time, a mineral acid peptized product of a hydrolyzed titanium compound is used as the titanium oxide source, and a water-soluble acidic strontium compound is used as the strontium oxide source. It can be produced by a method in which an alkaline aqueous solution is added to these mixed solutions at 60° C. or higher to cause a reaction, and then an acid treatment is performed.

(Atmospheric pressure heating reaction method)
As the titanium oxide source, a mineral acid peptized product of a hydrolyzed titanium compound is used. Preferably, metatitanic acid having an SO ₃ content of 1.0% by mass or less, preferably 0.5% by mass or less obtained by a sulfuric acid method is adjusted to pH 0.8 or more and 1.5 or less with hydrochloric acid. A peptized product can be used. A metatitanic acid having an SO ₃ content of more than 1.0% by mass is not preferable because the peptization does not proceed.

As the strontium oxide source, metal nitrates, hydrochlorides and the like can be used, and for example, strontium nitrate and strontium chloride can be used.

A caustic alkali can be used as the aqueous alkali solution, but an aqueous sodium hydroxide solution is preferable.

In the above-mentioned production method, as a factor that affects the particle size of the obtained strontium titanate particles, the mixing ratio of the titanium oxide source and the strontium oxide source during the reaction, the titanium oxide source concentration in the initial stage of the reaction, and the addition of the alkaline aqueous solution The temperature and the addition rate of the above are listed, and can be appropriately adjusted in order to obtain a desired particle size and particle size distribution. In addition, it is preferable to prevent the mixture of carbon dioxide gas, for example, by performing the reaction in a nitrogen gas atmosphere in order to prevent the formation of carbonate in the reaction process.

In the above-mentioned production method, factors affecting the dielectric constant of the obtained strontium titanate particles include conditions/operations that disrupt the crystallinity of the particles. In particular, even in the case of strontium titanate as in the present invention, in order to obtain particles having a low dielectric constant, it is preferable to carry out an operation of giving energy that disturbs crystal growth in a state where the concentration of the reaction solution is increased. The method includes, for example, adding micro bubbling with nitrogen in the crystal growth step.

The mixing ratio of the titanium oxide source and the strontium oxide source during the reaction is preferably 0.9 or more and 1.4 or less, and more preferably 1.05 or more and 1.20 or less in terms of the molar ratio of SrO/TiO ₂ . When the SrO/TiO ₂ molar ratio is 1.0 or less, not only the metal titanate but also unreacted titanium oxide tends to remain in the reaction product. The strontium oxide source has a relatively high solubility in water, whereas the titanium oxide source has a low solubility in water. Therefore, when the SrO/TiO ₂ molar ratio is 1.0 or less, the reaction product is only metal titanate. However, unreacted titanium oxide is likely to remain. As the concentration of the titanium oxide source at the initial stage of the reaction, TiO ₂ is suitably 0.05 mol/L or more and 1.3 mol/L or less, preferably 0.08 mol/L or more and 1.0 mol/L or less.

When the temperature at which the aqueous alkaline solution is added is 100° C. or higher, a pressure vessel such as an autoclave is required, and a range of 60° C. or higher and 100° C. or lower is suitable for practical use. Regarding the addition rate of the alkaline aqueous solution, the slower the addition rate, the larger the particle size of the metal titanate particles, and the faster the addition rate, the smaller the particle size of the metal titanate particles. The addition rate of the alkaline aqueous solution is 0.001 equivalents/h or more and 1.2 equivalents/h or less, preferably 0.002 equivalents/h or more and 1.1 equivalents/h or less with respect to the charged raw materials. It can be appropriately adjusted according to the particle size to be used.

(Acid treatment)
In the production method of the present invention, it is preferable to further subject the metal titanate particles obtained by the atmospheric pressure heating reaction to an acid treatment. When the metal titanate particles were synthesized by performing the atmospheric pressure heating reaction, when the mixing ratio of the titanium oxide source and the strontium oxide source was more than 1.0 in terms of the molar ratio of SrO/TiO ₂ , it remained after the reaction. Unreacted metal sources other than titanium react with carbon dioxide gas in the air to produce impurities such as metal carbonate. Further, if impurities such as metal carbonate remain on the surface, the organic surface treatment agent cannot be uniformly coated due to the impurities when the organic surface treatment for imparting hydrophobicity is performed. Therefore, it is preferable to carry out acid treatment after adding the alkaline aqueous solution in order to remove the unreacted metal source.

In the acid treatment, it is preferable to adjust the pH to 2.5 or more and 7.0 or less, more preferably pH 4.5 or more and 6.0 or less using hydrochloric acid. As the acid, nitric acid, acetic acid or the like can be used for the acid treatment in addition to hydrochloric acid. The use of sulfuric acid is not preferable because it produces a metal sulfate having a low solubility in water.

The above is the method for producing strontium titanate.

[Other external additives]
In the toner of the present invention, in addition to the above-mentioned silica particles and strontium titanate particles used as inorganic particles having a rectangular parallelepiped or a cube, other inorganic fine powder may be added as necessary in order to adjust the charge amount and the fluidity. It can also be contained. The inorganic fine powder may be internally added to the toner particles or may be mixed with the toner particles as an external additive. As the external additive, inorganic fine powder such as silica, titanium oxide, aluminum oxide, magnesium oxide, calcium carbonate is preferable. The inorganic fine powder may be hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil, or a mixture thereof.

The external additive is preferably used in an amount of 0.1 part by mass or more and 10.0 parts by mass or less based on 100 parts by mass of the toner particles. For mixing the toner particles and the external additive, a known mixer such as a Henschel mixer can be used.

[Binder resin]
The binder resin used in the toner of the present invention is not particularly limited, and the following polymers or resins can be used.

For example, polystyrene, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, and their substitution products; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers. , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl Styrene-based copolymers such as ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, Acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone-indene resin, petroleum-based resin and the like can be used.

Among these, it is preferable to use a polyester resin from the viewpoint of low-temperature fixability and chargeability control.

The polyester resin preferably used in the present invention is a resin having a “polyester unit” in the binder resin chain. Specific examples of the component constituting the polyester unit include a divalent or higher valent alcohol monomer component, a divalent or higher carboxylic acid, a divalent or higher carboxylic acid anhydride, and a divalent or higher carboxylic acid ester. And a monomer component.

Examples of the divalent or higher alcohol component include the following. Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2. 0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (6) Alkylene oxide adduct of bisphenol A such as 2,2,2-bis(4-hydroxyphenyl)propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 ,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, poly Tetramethylene glycol, sorbit, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5- Pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like.

The alcohol monomer component preferably used among these is an aromatic diol, and in the alcohol monomer component constituting the polyester resin, the aromatic diol is preferably contained in a proportion of 80 mol% or more.

On the other hand, examples of the acid monomer component such as the divalent or higher carboxylic acid, the divalent or higher carboxylic acid anhydride, and the divalent or higher carboxylic acid ester include the following. Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or their anhydrides; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or their anhydrides; alkyl groups or alkenyls having 6 to 18 carbon atoms Succinic acid substituted with a group or an anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or an anhydride thereof.

Among these, the acid monomer components preferably used are polyvalent carboxylic acids such as terephthalic acid, succinic acid, adipic acid, fumaric acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and their anhydrides.

The acid value of the polyester resin is preferably 20 mgKOH/g or less from the viewpoint of the dispersibility of the pigment and the stability of the triboelectric charge amount.

The acid value can be set within the above range by adjusting the type and blending amount of the monomer used in the resin. Specifically, it can be controlled by adjusting the alcohol monomer component ratio/acid monomer component ratio and the molecular weight during resin production. Further, it is possible to control the reaction of the terminal alcohol with a polyvalent acid monomer (for example, trimellitic acid) after the condensation polymerization of the ester.

[Colorant]
Examples of the colorant that can be contained in the toner of the present invention include the following.

Examples of the black colorant include carbon black; those obtained by toning black with a yellow colorant, a magenta colorant and a cyan colorant. As the colorant, a pigment may be used alone, but it is more preferable to use a dye and a pigment together to improve the sharpness from the viewpoint of the image quality of a full-color image.

Examples of magenta coloring pigments include the following. C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:1, 58, 60, 63, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; I. Pigment Violet 19; C.I. I. Butt Red 1, 2, 10, 13, 15, 23, 29, 35.

Examples of magenta coloring dyes include the following. C. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; C.I. I. Disperse Red 9; C.I. I. Solvent Violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; C.I. I. Basic dyes such as Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Examples of cyan color pigments include the following. C. I. Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, 17; C.I. I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment having 1 to 5 phthalimidomethyl groups substituted on the phthalocyanine skeleton.

Examples of cyan coloring dyes include C.I. I. There is Solvent Blue 70.

Examples of the yellow coloring pigment include the following. C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; I. Bat Yellow 1, 3, 20.

Examples of yellow coloring dyes include C.I. I. There is Solvent Yellow 162.

The amount of the colorant used is preferably 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

[wax]
Examples of the wax used in the toner of the present invention include the following.

Hydrocarbon wax such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymer, microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxide of hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof; Waxes containing fatty acid ester such as carnauba wax as a main component; deoxidized fatty acid ester such as carnauba wax, which is partially or entirely deoxidized.

Further, the following may be mentioned. Saturated straight chain fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid and parinaric acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl alcohol, melyl alcohol Saturated alcohols such as sil alcohol; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, montanic acid, and stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl alcohol, melyl alcohol Esters with alcohols such as sil alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearin Saturated fatty acid amides such as acid amides; unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, N,N'dioleyl sebacic acid amide; m -Aromatic bisamides such as xylene bisstearic acid amide and N,N' distearyl isophthalic acid amide; Aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally with metallic soap Waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid; partial esterification products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; vegetable oils and fats A methyl ester compound having a hydroxyl group obtained by hydrogenation of.

Among these waxes, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax, and fatty acid ester waxes such as carnauba wax are preferable from the viewpoint of improving low temperature fixability and hot offset resistance.

The content of the wax is preferably 1.0 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the binder resin. When the content of the wax is within this range, hot offset resistance at high temperature can be efficiently exhibited.

In addition, from the viewpoint of both the storage stability of the toner and the high temperature offset resistance at the same time, in the endothermic curve at the time of temperature increase measured by a differential scanning calorimeter (DSC), the maximum existing in the temperature range of 30°C to 200°C The peak temperature of the endothermic peak is preferably 50° C. or higher and 110° C. or lower.

[Wax dispersant]
In order to improve the dispersibility of the wax in the binder resin, a resin having both a polar part close to the wax component and a part close to the resin polarity may be added as a wax dispersant. Specifically, a styrene acrylic resin graft-modified with a hydrocarbon compound is preferable.

Introducing a cyclic hydrocarbon group or an aromatic ring into the resin portion of the wax dispersant improves the charge retention of the toner. This is preferable because it prevents the toner particles from deteriorating the charging assisting property of the strontium titanate particles of the present invention.

[Charge control agent]
The toner may contain a charge control agent, if necessary. As the charge control agent contained in the toner, known charge control agents can be used, but in particular, a metal compound of an aromatic carboxylic acid which is colorless and has a high charging speed of the toner and which can stably maintain a constant charge amount is preferable.

Examples of the negative charge control agent include the following. Salicylic acid metal compound, naphthoic acid metal compound, dicarboxylic acid metal compound, polymeric compound having sulfonic acid or carboxylic acid in the side chain, polymeric compound having sulfonic acid salt or sulfonic acid ester compound in the side chain, carboxylate Alternatively, polymer type compounds having a carboxylic acid ester compound in the side chain, boron compounds, urea compounds, silicon compounds, calixarene. Examples of the positive charge control agent include quaternary ammonium salts, polymer type compounds having the quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds. The charge control agent may be added internally or externally to the toner particles. The addition amount of the charge control agent is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[Developer]
Although the toner of the present invention can be used as a one-component developer, it is preferably mixed with a magnetic carrier and used as a two-component developer in order to further improve dot reproducibility. It is also preferable in that a stable image can be obtained for a long period of time.

The following known magnetic carriers can be used as the magnetic carrier. Iron powder whose surface is oxidized, or unoxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium and rare earth, alloy particles thereof, oxide particles A magnetic substance-dispersed resin carrier (so-called resin carrier) containing a magnetic substance such as ferrite, or a magnetic substance and a binder resin that holds the magnetic substance in a dispersed state.

When the toner of the present invention is mixed with a magnetic carrier to be used as a two-component developer, the carrier mixing ratio at that time is 2% by mass or more and 15% by mass or less, as the toner concentration in the two-component developer. When 4% by mass or more and 13% by mass or less, good results are usually obtained.

[Production method]
The method for producing the toner of the present invention is not particularly limited as long as it is a conventionally known toner production method such as an emulsion aggregation method, a melt kneading method, and a dissolution suspension method, but the melt kneading method is preferable from the viewpoint of enhancing the dispersibility of raw materials. ..

The melt-kneading method is characterized in that a toner composition, which is a raw material of toner particles, is melt-kneaded and the obtained kneaded product is pulverized. An example of the manufacturing method will be described.

In the raw material mixing step, a colorant containing an amorphous polyester resin, a crystalline polyester resin and a compound represented by the above formula (1) as a material constituting the toner particles, and if necessary, a wax, a charge control agent, etc. The other components are weighed in predetermined amounts, blended, and mixed. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a mechano hybrid (manufactured by Nippon Coke Industry Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse other raw materials in the binder resin. In the melt-kneading process, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used, and a single-screw or twin-screw extruder is mainly used because of its superiority in continuous production. There is. For example, a KTK twin screw extruder (manufactured by Kobe Steel, Ltd.), a TEM twin screw extruder (manufactured by Toshiba Machine Co., Ltd.), a PCM kneader (manufactured by Ikegai Corp.), a twin screw extruder (Kai).・C-K company), Co-kneader (Bus company), Needex (Nippon Coke Industry Co., Ltd.) and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with a two-roll mill or the like and cooled with water or the like in the cooling step.

Next, the cooled product of the resin composition is crushed to a desired particle size in a crushing step. In the crushing step, for example, after roughly crushing with a crusher such as a crusher, hammer mill, or feather mill, further fine crushing with a fine crusher. As a fine crusher, a Kryptron system (made by Kawasaki Heavy Industries, Ltd.), a super rotor (made by Nisshin Engineering Co., Ltd.), a turbo mill (made by Freund Turbo Co., Ltd.) and an air jet type fine crusher And so on.

Then, if necessary, an inertia classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.), a centrifugal classification type turboplex (manufactured by Hosokawa Micron Co., Ltd.), a TSP separator (manufactured by Hosokawa Micron Co., Ltd.), and a faculty (Hosokawa Micron Co., Ltd.) The toner particles are obtained by classification using a classifier such as the one manufactured by Co., Ltd. or a sieving machine.

The weight average diameter of the toner particles is preferably 4.0 μm or more and 8.0 μm or less because the effect of the external additive of the present invention can be sufficiently obtained. Further, the circularity of the toner particles may be increased by applying mechanical impact force to the particles or performing heat treatment with hot air or the like. The average circularity is preferably 0.962 or more and 0.972 or less in order to increase the opportunity of charge transfer between the toner particles and the frictional rubbing force, and to increase the charging rising speed.

External additives selected as necessary are added to the toner particles manufactured by the manufacturing method as described above and mixed (externally added). Examples of the mixing device include a double mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a mechano hybrid (manufactured by Nippon Coke Industry Co., Ltd.).

The methods for measuring various physical properties of toner and raw materials will be described below.

[Calculation of number average particle size of inorganic fine particles]
The number average particle diameter of the silica particles and the inorganic particles having a rectangular parallelepiped or a cube is calculated from an image of the toner surface taken by Hitachi Ultra High Resolution Field Emission Scanning Electron Microscope S-4800 (Hitachi High Technologies Co., Ltd.). It The image capturing conditions of S-4800 are as follows.

(1) Preparation of sample A sample table (aluminum sample table 15 mm x 6 mm) is thinly coated with a conductive paste, and toner is sprayed on it. Further, air blow is performed to remove excess toner from the sample table and dry it sufficiently. The sample table is set on the sample holder, and the sample table height is adjusted to 36 mm by the sample height gauge.

(2) S-4800 Observation Condition Setting The number average diameter is calculated using the image obtained by the backscattered electron image observation of S-4800. When measuring the coverage, elemental analysis is performed in advance by an energy dispersive X-ray analyzer (EDAX) to exclude particles other than silicon compound particles on the toner surface, and then the measurement is performed. Inject liquid nitrogen into the anti-contamination trap attached to the mirror body of S-4800 until it overflows, and leave it for 30 minutes. The "PC-SEM" of S-4800 is started and flushing (cleaning of the FE chip which is the electron source) is performed. Click the accelerating voltage display area on the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Execute after confirming that the flushing strength is 2. Confirm that the emission current due to flashing is 20 to 40 μA. Insert the sample holder into the sample chamber of the S-4800 body. Press [Origin] on the control panel and move the sample holder to the observation position.

Click the acceleration voltage display to open the HV setting dialog and set the acceleration voltage to [1.1 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select SE detectors [Up (U)] and [+BSE], and select [+BSE] in the selection box to the right. L. A. 100] is selected and the mode is set to observe with a backscattered electron image. Similarly, in the [Basic] tab of the operation panel, set the probe current of the electron optical system condition block to [Normal], the focus mode to [UHR], and the WD to [4.5 mm]. Press the [ON] button on the acceleration voltage display of the control panel to apply the acceleration voltage.

(3) Focus adjustment Rotate the focus knob [COARSE] on the operation panel to adjust the aperture alignment when the focus is adjusted to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. Rotate the STIGMA/ALIGNMENT knobs (X, Y) on the operation panel to move the displayed beam to the center of the concentric circles. Next, select [Aperture] and turn the STIGMA/ALIGNMENT knobs (X, Y) one by one to stop the movement of the image or adjust the movement so as to minimize the movement. Close the aperture dialog and use auto focus to focus. After that, the magnification is set to 80,000 (80k) times, the focus knob is adjusted in the same manner as described above, the focus is adjusted using the STIGMA/ALIGNMENT knob, and the focus is adjusted again by the autofocus. Repeat this operation again to focus. Here, if the angle of inclination of the observation surface is large, the measurement accuracy of the coverage rate tends to be low, so by selecting one that simultaneously focuses on the entire observation surface when adjusting the focus, select one that has the smallest possible surface inclination. And analyze.

(4) Image storage Brightness matching is performed in the ABC mode, and a picture is taken with a size of 640×480 pixels and stored. The following analysis is performed using this image file. One photograph is taken for each toner, and an image is obtained for at least 25 particles of toner.

(5) Image analysis The particle size of at least 500 inorganic fine particles on the toner surface is measured to determine the number average particle size. In the present invention, image analysis software Image-Pro Plus ver. The number average diameter is calculated by binarizing the image obtained by the above-described method using 5.0.

[Rectangular or cubic content of strontium titanate particles]
From the aforementioned electron microscope image, the number of particles having a rectangular parallelepiped or cubic shape among the strontium titanate fine particles of 10 nm or more and 90 nm or less is counted, and the number% with respect to the total number of strontium titanate of 10 nm or more and 90 nm or less is calculated. ..

[Measurement method of weight average particle diameter (D4) of toner particles]
The weight average particle diameter (D4) of the toner particles is the same as that of a precise particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with an aperture tube of 100 μm by a pore electrical resistance method. Measured with 25,000 effective measurement channels using the attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter Co., Ltd.) for setting measurement conditions and analyzing measurement data. Then, the measurement data is analyzed and calculated.

The electrolytic aqueous solution used for the measurement may be prepared by dissolving special grade sodium chloride in ion-exchanged water so that the concentration becomes about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used. ..

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

On the "Standard measurement method (SOM) change screen" of the dedicated software, the total count number in the control mode is set to 50,000 particles, the measurement number is once, and the Kd value is "standard particle 10.0 μm" (Beckman -Set the value obtained using Coulter Co., Ltd. The threshold and noise level are automatically set by pressing the threshold/noise level measurement button. Further, the current is set to 1,600 μA, the gain is set to 2, and the electrolytic solution is set to ISOTON II, and the check is made to the flash of the aperture tube after the measurement.

On 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 or more and 60 μm or less.

The specific measuring method is as follows.

(1) Approximately 200 mL of the electrolytic aqueous solution was placed in a glass 250 mL round-bottom beaker for exclusive use with Multisizer 3, set on a sample stand, and the stirrer rod was stirred counterclockwise at 24 revolutions/second. Then, the dirt and air bubbles in the aperture tube are removed by the "aperture flush" function of the analysis software.

(2) About 30 mL of the electrolytic aqueous solution is placed in a 100 mL flat-bottom beaker made of glass, and about 0.3 mL of the following diluent as a dispersant is added to this.
Diluting liquid: "Contaminone N" (10% by mass aqueous solution of non-ionic surfactant, anionic surfactant, organic builder, pH 7 precision measuring instrument neutral detergent for cleaning, manufactured by Wako Pure Chemical Industries, Ltd. ) Was diluted 3 times by mass with ion-exchanged water

(3) Two oscillators with an oscillation frequency of 50 kHz are installed with their phases shifted by 180 degrees, and a predetermined amount of ion-exchanged water is put into the water tank of the following ultrasonic disperser whose electrical output is 120 W. About 2 mL of the Contaminone N is added to the water tank.
-Ultrasonic disperser: "Ultrasonic Dispersion System Tetra 150" (manufactured by Nikkaki Bios Co., Ltd.)

(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker becomes maximum.

(5) About 10 mg of toner is added little by little to the electrolytic aqueous solution in a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. In the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted so as to be 15°C or higher and 40°C or lower.

(6) To the round-bottom beaker (1) installed in the sample stand, drop the toner-dispersed aqueous electrolyte solution (5) with a pipette, and adjust so that the measured concentration is about 5%. .. Then, the measurement is performed until the number of measured particles reaches 50,000.

(7) The measurement data is analyzed by the dedicated software attached to the apparatus to calculate the weight average particle diameter (D4). The “average diameter” on the analysis/volume statistical value (arithmetic mean) screen when the graph/volume% is set with the dedicated software is the weight average particle diameter (D4).

[Measuring method of average circularity]
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 work.

The specific measuring method is as follows. First, about 20 mL of ion-exchanged water from which impure solids and the like have been removed beforehand is placed in a glass container. In this, as a dispersant, "Contaminone N" (a nonionic surfactant, an anionic surfactant, a 10 mass% aqueous solution of a neutral detergent for washing precision measuring instruments of pH 7 comprising an organic builder, Wako Pure Chemical Industries, Ltd. )) was diluted about 3 times by mass with ion-exchanged water, and about 0.2 mL of a diluted solution was added. Further, about 0.02 g of a measurement sample is added, and a dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion liquid for measurement. At that time, the dispersion is appropriately cooled so that the temperature of the dispersion becomes 10° C. or higher and 40° C. or lower. As the ultrasonic disperser, a tabletop type ultrasonic cleaner disperser having an oscillation frequency of 50 kHz and an electric output of 150 W (“VS-150” (manufactured by Vervo Crea Co., Ltd.)) was used, and a predetermined amount in the water tank. Ion-exchanged water is added, and about 2 mL of the Contaminone N is added to the water tank.

The flow-type particle image analyzer equipped with a standard objective lens (10 times) was used for the measurement, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the above procedure is introduced into the flow-type particle image analyzer, and 3,000 toner particles are measured in the HPF measurement mode and the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analyzed 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.

Prior to the measurement, standard latex particles (“SEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific Co., Ltd. were diluted with ion-exchanged water) for automatic focus adjustment. After that, it is preferable to perform focus adjustment every two hours from the start of measurement.

In the examples of the present application, a flow-type particle image analyzer which has been calibrated by Sysmex Corporation and has been issued a calibration certificate issued by Sysmex Corporation was used. The measurement was performed under the same measurement and analysis conditions as when the calibration certificate was received, except that the analysis particle size was limited to the equivalent circle diameter of 1.985 μm or more and less than 39.69 μm.

Hereinafter, the present invention will be described with reference to manufacturing examples and examples.

[Inorganic particles having a rectangular parallelepiped or a cube: Production example of strontium titanate particles]
The metatitanic acid obtained by the sulfuric acid method was subjected to a deironing bleaching treatment, an aqueous sodium hydroxide solution was added to adjust the pH to 9.0, and a desulfurization treatment was performed. Then, the mixture was neutralized to a pH of 5.8 with hydrochloric acid and washed with water by filtration. Water was added to the washed cake to form a TiO ₂ slurry having a concentration of 1.5 mol/L, and then hydrochloric acid was added to adjust the pH to 1.5 and peptization treatment was performed.

Desulfurized and peptized metatitanic acid was collected as TiO ₂ and charged into a 3 L reaction vessel. After adding an aqueous strontium chloride solution to the peptized metatitanic acid slurry so that the SrO/TiO ₂ molar ratio was 1.15, the TiO ₂ concentration was adjusted to 0.8 mol/L. Next, after heating to 90° C. with stirring and mixing, 444 mL of 10N aqueous sodium hydroxide solution was added over 45 minutes while microbubbles of nitrogen gas were performed at 600 ml/min, and then 400 mL of microbubbles of nitrogen gas were added. The mixture was stirred at 95° C. for 1 hour while being performed at 1/min.

Then, the reaction slurry was stirred while flowing cooling water of 10° C. into the jacket of the reaction vessel and rapidly cooled to 15° C. Hydrochloric acid was added until pH 2.0 and stirring was continued for 1 hour. After the obtained precipitate was decanted and washed, 6N hydrochloric acid was added to adjust the pH to 2.0, 7.0 mass% of n-octylethoxysilane was added to the solid content, and the mixture was stirred for 18 hours. The mixture was neutralized with a 4N aqueous sodium hydroxide solution, stirred for 2 hours, filtered and separated, and dried in the atmosphere at 120° C. for 8 hours to obtain a powder. The powder showed a diffraction peak of strontium titanate by powder X-ray diffraction measurement. In addition, the average primary particle diameter calculated on the basis of number by electron microscope observation was 35 nm (strontium titanate particles 3).
The strontium titanate particles 1, 2, 4 to 6 were manufactured by partially changing the above manufacturing conditions. Table 1 shows the number average diameters of the produced strontium titanate particles 1 to 6.

The particle size used was adjusted to 300 nm or less that would not damage the photosensitive drum and its peripheral parts.

[Production Example of Silicas 1 to 21]
For the production of silica, the combustion furnace used a hydrocarbon-oxygen mixed burner having a double tube structure capable of forming an internal flame and an external flame. A two-fluid nozzle for injecting slurry is grounded at the center of the burner, and a raw material silicon compound is introduced. A hydrocarbon-oxygen combustible gas is injected from around the two-fluid nozzle to form a reducing atmosphere, an inner flame and an outer flame. By controlling the amounts and flow rates of the combustible gas and oxygen, the atmosphere and temperature, flame length, etc. are adjusted. Silica fine particles are formed from the silicon compound in the flame, and further fused to a desired particle size. Then, after cooling, it can be obtained by collecting with a bag filter or the like.

Hexamethylcyclotrisiloxane was used as a raw material silicon compound to produce silica having a number average particle diameter of 40 nm, and 100 parts by mass of the obtained silica was surface-treated with 0.1% by mass of dimethyl silicone oil to obtain silica 1 Got

Further, in the same manner as for silica 1, the size, temperature and flow rate of the flame by the burner were adjusted to obtain three particles having different particle sizes, and then surface treatment was performed with dimethyl silicone oil at 0% by mass to 5% by mass, respectively. Silicas 2 to 21 were obtained (Table 2 below). The number average particle diameters of the obtained silica measured by electron microscope observation were three kinds of 40 nm, 120 nm and 200 nm, respectively.

<Binder resin production example>
(Production example of polyester resin)
-Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane:
80.0 mol% based on total moles of polyhydric alcohol
-Polyoxyethylene (2.2)-2,2-bis(4-hydroxyphenyl)propane:
20.0 mol% based on the total moles of polyhydric alcohol
・Terephthalic acid: 80.0 mol% based on the total number of moles of polycarboxylic acid
Trimellitic anhydride: 20.0 mol% based on the total number of polycarboxylic acid moles
The above materials were charged into a reaction vessel equipped with a cooling pipe, a stirrer, a nitrogen introducing pipe, and a thermocouple. Then, 1.5 parts by mass of tin 2-ethylhexanoate (esterification catalyst) was added as a catalyst to 100 parts by mass of the total amount of the monomers. Next, after replacing the inside of the flask with nitrogen gas, the temperature was gradually raised with stirring, and the reaction was performed for 2.5 hours while stirring at a temperature of 200°C.

Furthermore, after lowering the pressure in the reaction tank to 8.3 kPa and maintaining it for 1 hour, it was cooled to 180° C., reacted as it was, and after confirming that the softening point measured according to ASTM D36-86 reached 110° C. The temperature was lowered to stop the reaction. The softening point (Tm) of the obtained polyester resin 1 was 115°C.

<Production example of wax dispersant>
In an autoclave reaction tank equipped with a thermometer and a stirrer, 300.0 parts by mass of xylene and 10.0 parts by mass of polypropylene (melting point 75° C.) were sufficiently dissolved and, after nitrogen substitution, 73.0 parts by mass of styrene and methacryl A mixed solution of 5.0 parts by mass of acid cyclohexyl, 12.0 parts by mass of butyl acrylate, and 250.0 parts by mass of xylene is added dropwise at 180° C. for 3 hours to perform polymerization. The temperature was maintained for 30 minutes to remove the solvent to obtain a wax dispersant.

<Toner Production Example 1>
-Polyester resin 100.0 parts by mass-3,5-di-t-butylsalicylic acid aluminum compound 0.1 part by mass-Fischer-Tropsch wax (maximum endothermic peak temperature 90°C) 5.0 parts by mass-Wax dispersant 6.5 Parts by mass C.I. I. Pigment Blue 15:3 5.0 parts by mass After mixing the raw materials shown in the above formulation with a Henschel mixer (FM75J type, manufactured by Mitsui Miike Kakoki Co., Ltd.) at a rotation speed of 20 s ⁻¹ and a rotation time of 5 min, The mixture was kneaded with a twin-screw kneader (PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a temperature of 130° C. and a barrel rotation speed of 200 rpm. The obtained kneaded product was cooled and coarsely pulverized with a hammer mill to 1 mm or less to obtain a coarsely pulverized product. The obtained coarsely pulverized product was finely pulverized by a mechanical pulverizer (T-250, manufactured by Turbo Industry Co., Ltd.). Further, classification was performed using a rotary classifier (200 TSP, manufactured by Hosokawa Micron Co., Ltd.) to obtain toner particles. The operating conditions of the rotary classifier (200 TSP, manufactured by Hosokawa Micron Co., Ltd.) were that the number of rotations of the classification rotor was 50.0 s ⁻¹ . The toner particles obtained had a weight average particle diameter (D4) of 5.7 μm.

To the obtained toner particles, 5.0% by mass of silica 1 and 0.2% by mass of hydrophobic silica fine particles having a primary average particle diameter of 10 nm, which were surface-treated with 10.0% by mass of hexamethyldisilazane, were added, and a Henschel mixer was used. (FM75J type, manufactured by Mitsui Miike Kakoki Co., Ltd.) were mixed at a rotation speed of 15 s ⁻¹ , a rotation time of 10 min, and a jacket temperature of 45° C.

Thereafter, 3.0 mass% of strontium titanate 1 was further added, and 0.8 mass% of hydrophobic silica fine particles having a primary average particle diameter of 10 nm surface-treated with 10.0 mass% of hexamethyldisilazane was added. After mixing for 30 s ⁻¹ , rotation time of 4 min, and jacket temperature of 20° C., the mixture was passed through an ultrasonic vibrating screen having openings of 54 μm to obtain a toner having an average circularity of 0.967.

<Toner Production Examples 2 to 21>
In the above-described production examples, toners 2 to 21 were obtained by adjusting the externally added strontium titanate and silica as shown in Table 2 to produce.

[Production Example of Magnetic Core Particles]
(Process 1: Weighing/Mixing process)
・Fe ₂ O ₃ 62.7 parts by mass ・MnCO ₃ 29.5 parts by mass ・Mg(OH) ₂ 6.8 parts by mass ・SrCO ₃ 1.0 part by mass Ferrite raw materials are added so that the above composition ratio becomes the above composition ratio. Weighed. Then, it was pulverized and mixed for 5 hours by a dry vibration mill using stainless beads having a diameter of 1/8 inch.

・Process 2 (temporary baking process):
The obtained pulverized product was made into pellets of about 1 mm square with a roller compactor. Coarse powder was removed from the pellets with a vibrating screen having openings of 3 mm, and then fine powder was removed with a vibrating screen having openings of 0.5 mm. Then, using a burner-type firing furnace, firing was performed at a temperature of 1,000° C. for 4 hours in a nitrogen atmosphere (oxygen concentration of 0.01 vol %) to produce a calcined ferrite. The composition of the obtained calcined ferrite is as follows.
(MnO) _a (MgO) _b (SrO) _c (Fe ₂ O ₃ ) _d

In the above formula, a=0.257, b=0.117, c=0.007, d=0.393

(Process 3: Crushing process)
After crushing to about 0.3 mm with a crusher, 30 parts by mass of water was added to 100 parts by mass of calcined ferrite using zirconia beads having a diameter of 1/8 inch, and crushed for 1 hour with a wet ball mill. The slurry was pulverized for 4 hours by a wet ball mill using alumina beads having a diameter of 1/16 inch to obtain a ferrite slurry (a finely pulverized product of calcined ferrite).

(Process 4: Granulation process)
To 100 parts by mass of calcined ferrite, 1.0 part by mass of ammonium polycarboxylate and 2.0 parts by mass of polyvinyl alcohol as a binder were added to the ferrite slurry. Then, using a spray dryer (manufacturer: Okawara Kakoki Co., Ltd.), the particles were granulated into spherical particles. After adjusting the particle size of the obtained particles, it was heated at a temperature of 650° C. for 2 hours using a rotary kiln to remove the organic components of the dispersant and the binder.

(Step 5: firing step)
In order to control the firing atmosphere, the temperature was raised from room temperature to a temperature of 1,300° C. in a nitrogen atmosphere (oxygen concentration of 1.00% by volume) in an electric furnace in 2 hours, and then at a temperature of 1,150° C. Burned for hours. Thereafter, the temperature was lowered to 60° C. over 4 hours, the nitrogen atmosphere was returned to the atmosphere, and the sample was taken out at a temperature of 40° C. or lower.

(Process 6: Selection process)
After disintegrating the agglomerated particles, a low magnetic product is cut by magnetic separation, coarse particles are removed by sieving with a sieve having an opening of 250 μm, and magnetic core particles having a volume distribution-based median diameter of 37.0 μm 1 Got

[Preparation of coating resin]
-Cyclohexyl methacrylate monomer 26.8 mass%
・Methyl methacrylate monomer 0.2 mass%
・Methyl methacrylate macromonomer 8.4 mass%
(Macromonomer having methacryloyl group at one end and having a weight average molecular weight of 5,000)
・Toluene 31.3% by mass
・Methyl ethyl ketone 31.3% by mass
・Azobisisobutyronitrile 2.0 mass%
Of the above materials, cyclohexylmethacrylate, methylmethacrylate, methylmethacrylate macromonomer, toluene, methylethylketone were placed in a four-necked separable flask equipped with a reflux condenser, a thermometer, a nitrogen introduction tube and a stirring device, and nitrogen gas was introduced. It was introduced and the inside of the system was replaced with nitrogen gas. Then, the temperature was raised to 80° C., azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours for polymerization. Hexane was injected into the obtained reaction product to precipitate a copolymer, and the precipitate was filtered off and dried in vacuum to obtain a coating resin 1. The obtained coating resin 1 was dissolved in 30 parts by mass, toluene 40 parts by mass, and methyl ethyl ketone 30 parts by mass to obtain a polymer solution 1 (solid content 30% by mass).

[Preparation of coating resin solution]
Polymer solution 1 (resin solid content concentration 30%) 33.3% by mass
・Toluene 66.4% by mass
・Carbon black 0.3% by mass
(Primary particle size 25 nm, nitrogen adsorption specific surface area 94 m ² /g, DBP oil absorption 75 mL/100 g)
The above material was dispersed with a paint shaker for 1 hour using zirconia beads having a diameter of 0.5 mm. The resulting dispersion was filtered with a 5.0 μm membrane filter to obtain a coating resin solution 1.

[Production example of magnetic carrier]
(Resin coating process)
The coating resin solution 1 was charged into a vacuum degassing type kneader maintained at room temperature so as to be 2.5 parts by mass as a resin component with respect to 100 parts by mass of the ferrite particles 1. After charging, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes, the solvent was volatilized at a certain level (80% by mass), the temperature was raised to 80° C. while mixing under reduced pressure, toluene was distilled off over 2 hours, and then the mixture was cooled. A low magnetic force product was separated from the obtained magnetic carrier by magnetic separation, passed through a sieve having an opening of 70 μm, and then classified by an air classifier to obtain a magnetic carrier having a volume distribution-based median diameter of 38.2 μm.

[Examples 1 to 15 and Comparative Examples 1 to 6]
Toner 1 and magnetic carrier were mixed with a V-type mixer (V-10 type: Tokuju Seisakusho Co., Ltd.) at 0.5 s ^{−1 at} a rotation time of 5 minutes so that the toner concentration was 10% by mass, and two components were mixed. Developer 1 is obtained. Similarly, toners 1 to 18 and magnetic carrier were mixed to obtain two-component developers 1 to 18.

The two-component developers and toners of Examples 1 to 15 and Comparative Examples 1 to 6 were evaluated as follows. Table 5 shows the evaluation results of Examples 1 to 15 and Comparative Examples 1 to 6.

The toner performance was evaluated according to the following methods (1) to (3).

(1) Image Density Fluctuation A full-color copying machine imagePRESS C800 manufactured by Canon Inc. was used as an image forming apparatus. (The station uses Cy station)

The developing voltage was initially adjusted so that the applied amount of toner on the FFh image was 0.45 mg/cm ² . The FFh image is a value in which 256 gradations are displayed in hexadecimal notation, 00H is the first gradation (white background portion), and FFh is the 256th gradation (solid portion).

Under a normal temperature and low humidity environment (temperature 23° C., relative humidity 5%), a durability image output test was performed on 10,000 solid images of 50% image duty, and the reflection density reaction rate of all images at that time was measured. As the evaluation paper, copy plain paper CS-680 (A4, basis weight 68 g/m ² , sold by Canon Marketing Japan Inc.) was used. An X-Rite color reflection densitometer (500 series: manufactured by X-Rite) was used to measure the image densities of all output images, and the standard deviation of fluctuations in the image density was calculated. The standard deviation of the fluctuation of the image density was evaluated based on the evaluation criteria shown below. During the 10000-sheet continuous paper feed period, the paper feed is performed under the same development conditions and transfer conditions (without calibration) as the first paper.
A: Concentration variation standard deviation: less than 0.02 B: Concentration variation standard deviation: 0.02 to less than 0.05 C: Concentration variation standard deviation: 0.05 to less than 0.10 D: Concentration variation standard deviation: 0. 10 or more and less than 0.20 E: Concentration variation standard deviation: 0.20 or more

[Calculation of residual rate of external additive on toner surface]
The residual ratio of the external additive on the toner surface is determined by elemental analysis by the energy dispersive X-ray analyzer (EDAX) or the wavelength dispersive fluorescent X-ray device (WDX) in the above (2) S-4800 observation condition setting. Ask by doing. For example, C, O, Si, Ti, Sr, vapor deposition elements, etc. are set to be detected by measurement, and the detection amounts of the external additive elements Si and Sr on the toner surface are measured at the initial stage and after the durability test, and the durability test is performed. The ratio of the subsequent Si/Sr detection amount HB and the initial Si/Sr detection amount HA is the residual ratio of the toner external additive.

The specific procedure is roughly as described above. For details of the work, toner is lightly pressure-bonded to the sample table, the surface is vapor-deposited, and the sample is inserted into the sample chamber of the mirror. After that, the accelerating voltage is set to an appropriate value, and the surface analysis of the toner surface is performed three times or more at different places, and the average is calculated.

This operation is performed at the initial stage and after the endurance of the same type of toner, and the residual toner rate is calculated. In this measurement, in order to minimize the influence of the same component contained in the toner, the process of excluding the value of the toner without the external additive from the initial value and the value after the durability test is performed, or the outermost surface is The residual rate of the toner external additive may be obtained by the same procedure using an X-ray photoelectron spectroscope capable of analysis. In this study, the toner remaining inside the apparatus when 30000 sheets of A4 paper were printed by the same machine as described in (1) Image density fluctuation was adopted as the toner after the durability test.
A: 65% or more B: 60% or more and less than 65% C: 55% or more and less than 60% D: 50% or more and less than 55% E: Less than 50%

As shown by the above results, when the toner of the present invention having silica particles and cuboidal or cubic inorganic particles on the toner surface is used, toner charging property, durability, fluidity and blocking resistance can be obtained. Therefore, a high quality image can be stably obtained.

M1 two-dimensional structure model 1, M2-1 two-dimensional structure model 2, M2-2 two-dimensional structure model 3, M3 two-dimensional structure model 4, 101 silica particles, 102 rectangular parallelepiped or cubic inorganic particles, P1 Two-dimensional structure 1, P2-1 Two-dimensional structure 2, P3 Two-dimensional structure 4, 103 Silica particles, 104 Inorganic particles having cuboids or cubes (strontium titanate particles)

Claims (8)

A toner containing toner particles and an external additive,
The external additives include (i) silica particles having a number average particle size of primary particles of 40 nm or more and 200 nm or less, and (ii) a number average particle size of primary particles of 10 nm or more and 90 nm or less, and an inorganic material having a rectangular parallelepiped or a cube. Particles and
When the number average particle diameter of the silica particles is DA and the number average particle diameter of the inorganic particles is DB,
DA-DB>0
Toner characterized by satisfying the relationship of. The toner according to claim 1, further comprising silicone oil on the surface of the silica particles. The toner according to claim 2, wherein the silicone oil is dimethyl silicone oil. The viscosity of the silicone oil, toner according to claim 2 or 3 300 mm ² / s or more 50000mm at ² / s or less. The toner according to claim ² , wherein the viscosity of the silicone oil is 3000 mm ² /s or more and 20000 mm ² /s or less. The toner according to claim 1, wherein the DA and the DB satisfy a relationship of DA-DB>5 nm. 7. The toner according to claim 2, wherein the silica particles contain 0.01% by mass or more and 5.00% by mass or less of the silicone oil. 8. The toner according to claim 1, wherein the inorganic particles having the rectangular parallelepiped or the cube are strontium titanate.

Images