JP2020181089A - toner - Google Patents

Abstract

To provide a toner with which a high-quality image can be formed even after printing of a large number of sheets, while the occurrence of fogging is prevented.SOLUTION: A toner includes toner particles 10. The toner particles 10 each include a toner base particle 11 containing a binder resin and an external additive attached to the surface of the toner base particle 11. The external additive includes, as external additive particles, titanate compound particles 12 doped with lanthanum and iron. The amount of lanthanum is 1.50 mass% or more with respect to the total mass of the titanate compound particles 12. The amount of the iron is 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the titanate compound particles 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to toner.

An image forming apparatus that forms an image using toner is required to be able to stably form an image having an image density of a certain level or higher even after printing a large number of sheets. For this reason, toners containing titanium acid compound particles (more specifically, strontium titanate particles and the like) are being studied as external additive particles. Since the titanium acid compound has a relatively high relative permittivity, the charge amount of the toner can be stably maintained even after printing a large number of sheets. Therefore, when a toner containing titanium acid compound particles is used as the external additive particles, an image having an image density of a certain level or higher can be stably formed even after printing a large number of sheets.

However, since the titanium acid compound particles generally have a polyhedral shape (specifically, a polyhedral shape having angles), for example, when the surface of the photoconductor drum is excessively polished by the titanium acid compound particles during printing of a large number of sheets. There is. If the surface of the photoconductor drum is excessively polished, image defects (streaks) may occur.

In order to suppress excessive polishing of the surface of the photoconductor drum, in the toner described in Patent Document 1, lanthanum-doped titanium acid compound particles (hereinafter, may be referred to as lanthanum-doped titanium acid compound particles) are externally attached. It is used as an agent particle. Since the lanthanum-doped titanium acid compound particles have a shape close to a sphere, excessive polishing of the surface of the photoconductor drum can be suppressed by using a toner containing the lanthanum-doped titanium acid compound particles as the external additive particles.

JP-A-2018-155912

However, it is difficult to obtain a toner capable of forming a high-quality image even after printing a large number of sheets (for example, 20,000 sheets) while suppressing the occurrence of fog only by the technique disclosed in Patent Document 1.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner capable of forming a high-quality image even after printing a large number of sheets (for example, 20,000 sheets) while suppressing the occurrence of fog. It is to be.

The toner according to the present invention contains toner particles. The toner particles include a toner mother particle containing a binder resin and an external additive adhering to the surface of the toner mother particle. The external additive contains titanium acid compound particles doped with lantern and iron as external additive particles. The amount of the lanthanum is 1.50% by mass or more with respect to the total mass of the titanium acid compound particles. The amount of iron is 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the titanic acid compound particles.

According to the present invention, it is possible to provide a toner capable of forming a high-quality image even after printing a large number of sheets (for example, 20,000 sheets) while suppressing the occurrence of fog.

It is a figure which shows an example of the cross-sectional structure of the toner particle contained in the toner which concerns on embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described. First, terms used in the present specification will be described. Toner is an aggregate of toner particles (for example, powder). The external additive is an aggregate of external additive particles (for example, powder). Unless otherwise specified, the evaluation results (values indicating the shape, physical properties, etc.) of the powder (more specifically, the powder of the toner particles, the powder of the external additive particles, etc.) are obtained from the powder. It is the number average of the values measured for each of the particles selected in a considerable number.

Unless otherwise specified, the measured value of the median volume diameter (D ₅₀ ) of the powder was measured using a laser diffraction / scattering type particle size distribution measuring device (“LA-950” manufactured by HORIBA, Ltd.). The median diameter. Unless otherwise specified, the number average primary particle diameter of the powder has the same area as the circle-equivalent diameter of 100 primary particles (Haywood diameter: projected area of the primary particles) measured using a scanning electron microscope. It is the number average value of the diameter of the circle). The number average primary particle diameter of the particles refers to the number average primary particle diameter of the particles in the powder (the number average primary particle diameter of the powder) unless otherwise specified.

The strength of chargeability is the ease of triboelectric charging unless otherwise specified. For example, a standard carrier provided by the Japan Imaging Society (standard carrier for negatively charged polar toner: N-01, standard carrier for positively charged polar toner: P-01) and a measurement target (for example, toner) are mixed and stirred. Then, the measurement target is triboelectrically charged. Before and after triboelectric charging, for example, a suction-type compact charge amount measuring device (“MODEL 212HS” manufactured by Trek Co., Ltd.) measures the charge amount to be measured. The larger the change in the amount of charge before and after triboelectric charging, the stronger the chargeability.

Unless otherwise specified, the measured value of the softening point (Tm) is a value measured using a high-grade flow tester (“CFT-500D” manufactured by Shimadzu Corporation). In the S-shaped curve (horizontal axis: temperature, vertical axis: stroke) measured by the heightened flow tester, the temperature that becomes "(baseline stroke value + maximum stroke value) / 2" becomes Tm (softening point). Equivalent to.

The "main component" of a material, unless otherwise specified, means the component most abundant in the material on a mass basis.

The strength of hydrophobicity can be expressed, for example, by the contact angle of water droplets (easiness of getting wet with water). The larger the contact angle of water droplets, the stronger the hydrophobicity. The hydrophobizing treatment refers to a treatment for strengthening the hydrophobicity.

The "alkyl group having 3 or more carbon atoms and 8 or less carbon atoms" is linear or branched and unsubstituted. Examples of the alkyl group having 3 or more carbon atoms and 8 or less carbon atoms include an n-propyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. Be done.

The "titanate compound" is a compound (crystal) containing at least titanium, oxygen, and a metal element other than titanium. "Titanic acid compound particles" are particles containing a titanium acid compound as a main component. The content of the titanium acid compound in the titanium acid compound particles is preferably 99% by mass or more and 100% by mass or less with respect to the total mass of the titanium acid compound particles.

Hereinafter, the compound and its derivative may be collectively referred to by adding "system" after the compound name. When the polymer name is represented by adding "system" after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative.

Further, in the following description, "elements (more specifically, lanthanum, iron, etc.) are doped" means that a part of the elements constituting the crystal of the titanium acid compound as the base material is the base material. It means that it is replaced with an element different from the constituent elements (more specifically, lanthanum, iron, etc.).

<Toner>
The toner according to this embodiment can be suitably used for developing an electrostatic latent image, for example, as a positively charged toner. The toner according to the present embodiment is an aggregate (for example, powder) of toner particles (particles having a configuration described later). The toner may be used as a one-component developer. Further, the toner and the carrier may be mixed using a mixing device (for example, a ball mill) to prepare a two-component developer.

The toner particles contained in the toner according to the present embodiment include a toner mother particle containing a binder resin and an external additive adhering to the surface of the toner mother particle. The external additive includes titanic acid compound particles (hereinafter, may be referred to as specific titanium acid compound particles) doped with lantern and iron as external additive particles. The amount of lanthanum is 1.50% by mass or more with respect to the total mass of the specific titanium acid compound particles. The amount of iron is 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the specific titanium acid compound particles.

Hereinafter, the amount of lanthanum with respect to the total mass of the specific titanic acid compound particles may be simply referred to as "amount of lanthanum". Further, the amount of iron with respect to the total mass of the specific titanic acid compound particles may be simply described as "amount of iron". Both the amount of lantern and the amount of iron are measured by an inductively coupled plasma emission spectrophotometer.

By providing the above-mentioned configuration, the toner according to the present embodiment can form a high-quality image even after printing a large number of sheets (for example, 20,000 sheets) while suppressing the occurrence of fog. The reason is presumed as follows.

Generally, when external additive particles having a shape close to a sphere are used, the external additive particles tend to be overcharged. The overcharged external additive particles may discharge to, for example, the surface of the photoconductor drum during printing of a large number of sheets (for example, 20,000 sheets), causing dielectric breakdown on the surface of the photoconductor drum. Dielectric breakdown is particularly likely to occur in a low temperature and low humidity environment. If dielectric breakdown occurs on the surface of the photoconductor drum, the surface of the photoconductor drum may be damaged. Damage to the surface of the photoconductor drum due to dielectric breakdown causes image defects (generation of black spots). Therefore, when lanthanum-doped titanium acid compound particles are usually used as the external additive particles, image defects (black spots) are likely to occur when forming an image after printing a large number of sheets.

On the other hand, in the toner according to the present embodiment, iron-doped specific titanium acid compound particles are used as the external additive particles. Iron has a moderately low electrical resistance. The amount of iron is 10 mass ppm or more. Therefore, the toner according to the present embodiment can suppress excessive charging of the specific titanium acid compound particles. Lanthanum is also doped in the specific titanium acid compound particles. The amount of lantern is 1.50% by mass or more. Therefore, the toner according to the present embodiment can suppress excessive polishing of the surface of the photoconductor drum, for example. Further, since the specific titanium acid compound particles contain a titanium acid compound having a relatively high relative permittivity, the amount of charge of the toner can be stably maintained even after printing a large number of sheets.

Therefore, according to the toner according to the present embodiment, even after printing a large number of sheets (for example, 20,000 sheets), the occurrence of image defects (more specifically, the generation of black spots, the generation of streaks, etc.) is suppressed. , An image having an image density of a certain level or higher can be stably formed. Therefore, according to the toner according to the present embodiment, a high-quality image can be formed even after printing a large number of sheets (for example, 20,000 sheets).

In addition, when external additive particles having low electrical resistance are usually used, fog is likely to occur. Fogging is particularly likely to occur in a high temperature and high humidity environment.

On the other hand, in the toner according to the present embodiment, the amount of iron is 100 mass ppm or less. As described above, in the toner according to the present embodiment, the upper limit of the amount of iron is set so that the electric resistance of the specific titanium acid compound particles is not excessively lowered. Therefore, according to the toner according to the present embodiment, the occurrence of fog can be suppressed.

In the present embodiment, the amount of iron is preferably 50 mass ppm or more in order to form a higher quality image after printing a large number of sheets.

In the present embodiment, the amount of lantern is preferably 1.70% by mass or more in order to form a higher quality image after printing a large number of sheets. Further, in the present embodiment, in order to further suppress the occurrence of black spots when forming an image after printing a large number of sheets, the amount of lantern is preferably 15.00% by mass or less, preferably 12.80% by mass. More preferably, it is less than%.

In the present embodiment, in order to form a higher quality image after printing a large number of sheets, the amount of the specific titanium acid compound particles is 0.1 part by mass or more with respect to 100 parts by mass of the toner mother particles. It is preferably 0.5 parts by mass or more, and more preferably 0.5 parts by mass or more. Further, in the present embodiment, in order to further suppress the occurrence of fog, the amount of the specific titanium acid compound particles is preferably 1.2 parts by mass or less with respect to 100 parts by mass of the toner mother particles. It is more preferably 0 parts by mass or less.

In the present embodiment, in order to form a higher quality image after printing a large number of sheets, the relative permittivity of the specific titanium acid compound particles is preferably 100 or more and 1200 or less, and 150 or more and 1180 or less. Is more preferable. The method for measuring the relative permittivity is the same method as in Examples described later or a method similar thereto.

The toner particles contained in the toner according to the present embodiment may be toner particles not provided with a shell layer, or may be toner particles having a shell layer (hereinafter, may be referred to as capsule toner particles). Good. In the capsule toner particles, the toner mother particles include a toner core containing a binder resin and a shell layer that covers the surface of the toner core. The shell layer contains a resin. For example, by covering the toner core that melts at a low temperature with a shell layer having excellent heat resistance, it is possible to achieve both heat storage stability and low temperature fixability of the toner. Additives may be dispersed in the resin constituting the shell layer. The shell layer may cover the entire surface of the toner core or may partially cover the surface of the toner core.

In the present embodiment, the toner mother particles further contain an internal additive (for example, at least one of a colorant, a mold release agent, a charge control agent, and a magnetic powder) in addition to the binder resin, if necessary. You may.

Hereinafter, the details of the toner according to the present embodiment will be described with reference to the drawings as appropriate. It should be noted that FIG. 1 to be referred to is schematically shown mainly for each component for easy understanding, and the size, number, shape, etc. of each of the illustrated components are shown for convenience of drawing creation. It may be different from the actual one.

[Structure of toner particles]
Hereinafter, the configuration of the toner particles contained in the toner according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an example of a cross-sectional structure of toner particles contained in the toner according to the present embodiment.

The toner particles 10 shown in FIG. 1 include a toner mother particle 11 containing a binder resin and an external additive adhering to the surface of the toner mother particle 11. The external additive contains the specific titanium acid compound particles 12 as the external additive particles. The amount of lanthanum contained in the specific titanium acid compound particles 12 is 1.50% by mass or more with respect to the total mass of the specific titanium acid compound particles 12. The amount of iron contained in the specific titanic acid compound particles 12 is 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the specific titanic acid compound particles 12.

In order to obtain a toner suitable for image formation, the volume median diameter (D ₅₀ ) of the toner matrix particles 11 is preferably 4 μm or more and 9 μm or less.

In order to further suppress the generation of streaks when forming an image after printing a large number of sheets, the number average circularity of the specific titanium acid compound particles 12 is preferably 0.79 or more and 1.00 or less, and is 0. It is more preferably .80 or more and 1.00 or less, and further preferably 0.84 or more and 1.00 or less. Further, in order to further suppress the occurrence of black spots when forming an image after printing a large number of sheets, the number average circularity of the specific titanium acid compound particles 12 is preferably 0.92 or less. The method for measuring the number average circularity is the same method as in Examples described later or a method similar thereto.

In order to form a higher image quality image after printing a large number of sheets, the number average primary particle diameter of the specific titanium acid compound particles 12 is preferably 20 nm or more and 80 nm or less, and more preferably 20 nm or more and 40 nm or less. preferable.

As described above, an example of the configuration of the toner particles contained in the toner according to the present embodiment has been described with reference to FIG.

[Elements of toner particles]
Next, the elements of the toner particles contained in the toner according to the present embodiment will be described.

(Bundling resin)
For example, the binder resin occupies 70% by mass or more of all the components of the toner mother particles. Therefore, it is considered that the properties of the binder resin have a great influence on the properties of the entire toner matrix particles. In order to obtain a toner having excellent low-temperature fixability, the toner mother particles preferably contain a thermoplastic resin as the binder resin, and contain the thermoplastic resin in a proportion of 85% by mass or more of the entire binder resin. Is more preferable. Examples of the thermoplastic resin include styrene resin, acrylic acid ester resin, olefin resin (more specifically, polyethylene resin, polypropylene resin, etc.), vinyl resin (more specifically, vinyl chloride resin, polyvinyl chloride, etc.). (Alcohol, vinyl ether resin, N-vinyl resin, etc.), polyester resin, polyamide resin, and urethane resin can be mentioned. Further, a copolymer of each of these resins, that is, a copolymer in which an arbitrary repeating unit is introduced into the above resin (more specifically, a styrene-acrylic acid ester resin, a styrene-butadiene resin, etc.) is also available. Can be used as a binder resin.

The thermoplastic resin is obtained by addition polymerization, copolymerization, or polycondensation of one or more kinds of thermoplastic monomers. The thermoplastic monomer is a monomer that becomes a thermoplastic resin by homopolymerization (more specifically, an acrylic acid ester-based monomer, a styrene-based monomer, etc.) or a monomer that becomes a thermoplastic resin by polycondensation (for example, polycondensation). A combination of a polyhydric alcohol and a polyvalent carboxylic acid that becomes a polyester resin).

In order to obtain a toner having excellent low-temperature fixability, the toner matrix particles preferably contain a polyester resin as the binder resin, and contain the polyester resin in a proportion of 80% by mass or more and 100% by mass or less of the entire binder resin. It is more preferable to do so. The polyester resin is obtained by polycondensing one or more polyhydric alcohols and one or more polyvalent carboxylic acids. Examples of the alcohol for synthesizing the polyester resin include divalent alcohols (more specifically, aliphatic diols, bisphenols, etc.) as shown below, and trihydric or higher alcohols. Examples of the carboxylic acid for synthesizing the polyester resin include a divalent carboxylic acid and a trivalent or higher carboxylic acid as shown below. In addition, instead of the polyvalent carboxylic acid, a polyvalent carboxylic acid derivative capable of forming an ester bond by polycondensation of an anhydride of the polyvalent carboxylic acid, polyvalent carboxylic acid halide or the like may be used.

Preferable examples of aliphatic diols include diethylene glycol, triethylene glycol, neopentyl glycol, 1,2-propanediol, α, ω-alkanediol (more specifically, ethylene glycol, 1,3-propanediol, etc.). 1,4-Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,12-dodecanediol, etc.) , 2-Buten-1,4-diol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Preferable examples of bisphenol include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct.

Preferable examples of trihydric or higher alcohols are sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentaerythritol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5- Examples include trihydroxymethylbenzene.

Preferable examples of divalent carboxylic acids include maleic acid, fumaric acid, succinic acid, succinic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, succinic acid, malonic acid. , 1,10-decandicarboxylic acid, succinic acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, etc.), And alkenyl succinic acid (more specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, isododecenyl succinic acid and the like).

Preferable examples of trivalent or higher valent carboxylic acids are 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1, 2,4-Butantricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empole trimeric acid.

(Colorant)
The toner mother particles may contain a colorant. As the colorant, a pigment or dye known according to the color of the toner can be used. In order to form a high-quality image using the toner, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

The toner mother particles may contain a black colorant. An example of a black colorant is carbon black. Further, the black colorant may be a colorant that has been toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

The toner mother particles may contain a color colorant. Examples of the color colorant include a yellow colorant, a magenta colorant, and a cyan colorant.

As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow (3,12,13,14,15,17,62,74,83,93,94,95,97,109,110,111,120,127,128,129,147,151,154,155 168, 174, 175, 176, 180, 181, 191 and 194), Naphthol Yellow S, Hansa Yellow G, and C.I. I. Bat yellow can be mentioned.

The magenta colorant is selected from the group consisting of, for example, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. More than one compound can be used. Examples of the magenta colorant include C.I. I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 , 184, 185, 202, 206, 220, 221 and 254).

As the cyan colorant, for example, one or more compounds selected from the group consisting of copper phthalocyanine compounds, anthraquinone compounds, and base dye lake compounds can be used. Examples of the cyan colorant include C.I. I. Pigment Blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, and 66), Phthalocyanine Blue, C.I. I. Bat Blue, as well as C.I. I. Acid blue can be mentioned.

(Release agent)
The toner mother particles may contain a release agent. The release agent is used, for example, to obtain a toner having excellent offset resistance. In order to obtain a toner having excellent offset resistance, the amount of the release agent is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

Examples of the release agent include ester wax, polyolefin wax (more specifically, polyethylene wax, polypropylene wax, etc.), microcrystalline wax, fluororesin wax, Fishertroph wax, paraffin wax, candelilla wax, and Montan wax. And Custer wax. Examples of the ester wax include natural ester wax (more specifically, carnauba wax, rice wax, etc.) and synthetic ester wax. In the present embodiment, one type of release agent may be used alone, or a plurality of types of release agents may be used in combination.

A compatibilizer may be added to the toner matrix particles in order to improve the compatibility between the binder resin and the release agent.

(Charge control agent)
The toner mother particles may contain a charge control agent. The charge control agent is used, for example, to obtain a toner having excellent charge stability or charge rise characteristics. The charging rise characteristic of the toner is an index of whether or not the toner can be charged to a predetermined charging level in a short time.

By incorporating a positively chargeable charge control agent into the toner mother particles, the cationicity (positive chargeability) of the toner mother particles can be strengthened. Further, by incorporating a negatively charged charge control agent into the toner mother particles, the anionic property (negative charge) of the toner mother particles can be strengthened.

Examples of positively charged charge control agents include pyridazine, pyrimidine, pyrazine, 1,2-oxazine, 1,3-oxazine, 1,4-oxazine, 1,2-thiazine, 1,3-thiazine, 1, 4-thiadine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6- Oxaziazine, 1,3,4-triazine, 1,3,5-triazine, 1,2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1, Adin compounds such as 2,4,6-oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline, quinoxalin; Adinfast Red FC, Adinfast Red 12BK, Adin Violet BO, Adin Brown 3G, Adinlite Direct dyes such as Brown GR, Azine Dark Green BH / C, Azin Deep Black EW, Azin Deep Black 3RL; Acidic dyes such as Niglosin BK, Niglosin NB, Niglosin Z; Alkalkylated amines; Alkylamides; Quaternary ammonium salts such as ammonium chloride, decyltrimethylammonium chloride, 2- (methacryloyloxy) ethyltrimethylammonium chloride, dimethylaminopropylacrylamide methyl chloride quaternary salt; resins containing a quaternary ammonium cation group can be mentioned. Only one of these charge control agents may be used, or two or more types of charge control agents may be used in combination.

An example of a negatively charged charge control agent is an organometallic complex which is a chelate compound. As the organometallic complex, one or more selected from the group consisting of an acetylacetone metal complex, a salicylic acid-based metal complex, and salts thereof is preferable.

In order to obtain a toner having excellent charge stability, the content of the charge control agent is preferably 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Magnetic powder)
The toner mother particles may contain magnetic powder. Examples of the material of the magnetic powder include ferromagnetic metals (more specifically, iron, cobalt, nickel, etc.) and their alloys, ferromagnetic metal oxides (more specifically, ferrite, magnetite, chromium dioxide, etc.). , And a material that has been subjected to a ferromagnetism treatment (more specifically, a carbon material to which ferromagnetism has been imparted by heat treatment, etc.). In the present embodiment, one kind of magnetic powder may be used alone, or a plurality of kinds of magnetic powder may be used in combination.

(External agent)
The toner particles contained in the toner according to the present embodiment include an external additive adhering to the surface of the toner matrix particles. The external additive contains one or more of the specific titanium acid compound particles as the external additive particles.

As the base material (doped titanium acid compound) of the specific titanium acid compound particles, for example, the composition is MTIO ₃ (M represents a metal element other than titanium, excluding lanthanum and iron). Examples thereof include the represented titanic acid compounds. Specific examples of the titanate compound composition represented by MTiO _3, strontium titanate (SrTiO _3), barium titanate (BaTiO _3), calcium titanate (CaTiO _3), magnesium titanate (MgTiO _3), and Lead titanate (PbTiO ₃ ) can be mentioned. The crystal structure of the titanium acid compound whose composition is represented by MTIO ₃ is usually a perovskite type crystal structure.

When a titanium acid compound having a composition represented by MTIO ₃ is used as the base material of the specific titanium acid compound particles, the lanthanum and iron can be used, for example, by substituting the site where the metal represented by M is arranged. It is incorporated into the crystal structure of the base metal. Hereinafter, the site where the metal represented by M is arranged is referred to as M site. Further, the specific titanium acid compound particles obtained by substituting lanthanum and iron for M sites are referred to as M site-substituted titanium acid compound particles.

The peak position of the powder X-ray diffraction pattern of the M-site-substituted titanium acid compound particles coincides with the peak position of the powder X-ray diffraction pattern of the crystal structure of the base material (titanate compound whose composition is represented by MTIO ₃ ). Therefore, if the peak position of the powder X-ray diffraction pattern of the specific titanium acid compound particles and the peak position of the powder X-ray diffraction pattern of the base material (the titanium acid compound whose composition is represented by MTIO ₃ ) match, the peak position is the same. It can be determined that the base material is doped with lantern and iron. Regarding the powder X-ray diffraction pattern, "the peak positions match" means that the values of the diffraction angles (2θ) match in the range of ± 0.5 degrees for the two peak positions to be compared.

In order to form a higher quality image after printing a large number of sheets, the specific barium titanate compound particles include strontium titanate particles doped with lanthanum and iron, and barium titanate particles doped with lanthanum and iron. , Or calcium titanate particles doped with lantern and iron are preferable.

The method for producing the specific titanium acid compound particles is not particularly limited. Further, in the toner according to the present embodiment, commercially available specific titanium acid compound particles can also be used.

Hereinafter, an example of a method for producing the specific titanium acid compound particles will be described. First, a treated product in which the titanium source is defibrated with mineral acid (hereinafter, may be referred to as a titanium source deflated product) and a metal element other than titanium (more specifically, strontium) constituting the base material. , Barium, calcium, etc.), lanthanum source, and iron source are mixed. Then, the alkaline aqueous solution is added to the mixture while heating the obtained mixture to a temperature of 50 ° C. or higher. Then, the mixture to which the alkaline aqueous solution is added is held at a temperature of 50 ° C. or higher for a predetermined time (for example, 30 minutes or more and 2 hours or less). The resulting product is then cooled and then hydrochloric acid is added to the product to give a precipitate. Next, the obtained precipitate is washed, filtered (solid-liquid separation), and then the obtained solid content is dried to obtain a powder of the specific titanium acid compound particles.

The amount of lanthanum can be adjusted in the above example of the method for producing the specific titanium acid compound particles by, for example, changing the amount of the lanthanum source with respect to the mass of the titanium source defibrated product. The amount of iron can be adjusted in the above-mentioned example of the method for producing the specific titanium acid compound particles, for example, by changing the amount of iron source with respect to the mass of the titanium source defibrated product. The number average circularity of the specific titanium acid compound particles can be adjusted, for example, by changing the amount of the lanthanum source with respect to the mass of the titanium source defibrated product in the above example of the method for producing the specific titanium acid compound particles. The average number of primary particle diameters of the specific titanium acid compound particles is determined by, for example, in an example of the method for producing the specific titanium acid compound particles, a mixture of a compound of a metal element other than titanium constituting the base material and a titanium source defibrated product. It can be adjusted by changing at least one of the ratio, the concentration of alkali in the alkaline aqueous solution, and the amount of the alkaline aqueous solution added. The relative permittivity of the specific titanium acid compound particles is determined in the above example of the method for producing the specific titanium acid compound particles, for example, the type of metal element other than titanium constituting the base material, and the iron source with respect to the mass of the titanium source unglazed product. And the amount of the lantern source relative to the mass of the titanium source defibrated product can be adjusted by changing at least one of them.

In order to further suppress the occurrence of fog in a high temperature and high humidity environment, it is preferable that the surface of the specific titanium acid compound particles is hydrophobized. As a method for obtaining specific titanium acid compound particles whose surface has been hydrophobized, for example, particles composed of a titanium acid compound doped with lantern and iron (hereinafter, may be referred to as a substrate) are hydrophobized. Examples include a method of treating with an agent. As the hydrophobizing agent, one or more selected from silicone oil, silazane compounds, and silane compounds are preferable, silane compounds are more preferable, and silane compounds having an alkoxy group and an alkyl group having 3 to 8 carbon atoms (more specific). Specifically, n-propyltrimethoxysilane, n-propyltriethoxysilane, isobutyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, etc.) are more preferable, and isobutyltrimethoxysilane is particularly preferable.

When the surface of a substrate is treated with a silane compound having an alkoxy group and an alkyl group having 3 or more and 8 or less carbon atoms, the hydroxy group generated by hydrolyzing the alkoxy group of the silane compound with water is the surface of the substrate. It undergoes a dehydration condensation reaction with the hydroxy group present in. By such a reaction, an alkyl group (hydrophobic group) having 3 to 8 carbon atoms is imparted to the surface of the substrate. That is, the surface of the specific titanoic acid compound particles hydrophobized with a silane compound having an alkoxy group and an alkyl group having 3 or more and 8 or less carbon atoms has an alkyl group having 3 or more and 8 or less carbon atoms.

Since the specific titanium acid compound particles having an alkyl group having 3 or more and 8 or less carbon atoms on the surface have relatively high hydrophobicity, the occurrence of fogging can be further suppressed in a high temperature and high humidity environment.

Examples of the method for hydrophobizing the substrate include a method of dropping or spraying the hydrophobizing agent toward the substrate while stirring the substrate, and then heating the substrate coated with the hydrophobizing agent, and a solution of the hydrophobizing agent. A method of heating the substrate coated with the hydrophobizing agent after adding the substrate to the inside can be mentioned. The hydrophobizing agent may be dissolved in an organic solvent. Alternatively, a commercially available hydrophobic agent may be diluted with an organic solvent before use.

In order to form a higher quality image after printing a large number of sheets while further suppressing the occurrence of fog, the specific titanic acid compound particles are doped with lanthanum and iron and have 3 or more and 8 or less carbon atoms. Strontium titanate particles having an alkyl group on the surface thereof are preferable, and strontium titanate particles having a lanthanum and iron doped on the surface and having an isobutyl group on the surface are more preferable.

The external additive may contain only the specific titanium acid compound particles as the external additive particles, and may further contain other external additive particles in addition to the specific titanium acid compound particles. In order to maintain good toner fluidity, the other external additive particles are preferably inorganic particles other than the specific titanium acid compound particles, and more preferably one or more selected from silica particles and titanium oxide particles.

The other external additive particles may be surface-treated. For example, when silica particles are used as other external additive particles, the surface of the silica particles may be imparted with hydrophobicity and / or positive chargeability by a surface treatment agent. Examples of the surface treatment agent include a coupling agent (more specifically, a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, etc.), a silazane compound (more specifically, a chain silazane compound, etc.). Cyclic silane compounds and the like) and silicone oils (more specifically, dimethyl silicone oils and the like) can be mentioned. As the surface treatment agent, one or more selected from a silane coupling agent and a silazane compound is particularly preferable. Preferable examples of the silane coupling agent include silane compounds (more specifically, methyltrimethoxysilane, aminosilane, etc.). Preferable examples of the silazane compound include HMDS (hexamethyldisilazane). When the surface of the silica substrate (untreated silica particles) is treated with a surface treatment agent, a large number of hydroxy groups (-OH) present on the surface of the silica substrate are partially or wholly derived from the surface treatment agent. Substituted with a functional group. As a result, silica particles having a functional group derived from the surface treatment agent (specifically, a functional group having a stronger hydrophobicity and / or positive charge than the hydroxy group) on the surface can be obtained.

In order to fully exert the function of the external additive while suppressing the detachment of the external additive from the toner mother particles, the amount of the external additive (when other external additive particles are used, the specified titanium The total amount of the acid compound particles and other external additive particles) is preferably 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner mother particles.

<Toner manufacturing method>
Next, a preferred method for producing the toner according to the above-described embodiment will be described. Hereinafter, the description of the components overlapping with the toner according to the above-described embodiment will be omitted.

[Preparation process of toner matrix particles]
First, toner mother particles are prepared by an agglutination method or a pulverization method.

The agglutination method includes, for example, an agglutination step and a coalescence step. In the agglomeration step, fine particles containing components constituting the toner matrix particles are agglomerated in an aqueous medium to form agglomerated particles. In the coalescence step, the components contained in the aggregated particles are coalesced in an aqueous medium to form toner matrix particles.

Next, the pulverization method will be described. According to the pulverization method, toner matrix particles can be prepared relatively easily, and the manufacturing cost can be reduced. When the toner mother particles are prepared by the pulverization method, the toner mother particles preparation step includes, for example, a melt-kneading step and a crushing step. The toner matrix particle preparation step may further include a mixing step before the melt kneading step. Further, the toner matrix particle preparation step may further include at least one of a fine pulverization step and a classification step after the pulverization step.

In the mixing step, the binder resin and the internal additive added as needed are mixed to obtain a mixture. In the melt-kneading step, the toner material is melted and kneaded to obtain a melt-kneaded product. As the toner material, for example, a mixture obtained in a mixing step is used. In the pulverization step, the obtained melt-kneaded product is cooled to, for example, room temperature (25 ° C.) and then pulverized to obtain a pulverized product. When it is necessary to reduce the diameter of the pulverized product obtained in the pulverization step, a step of further pulverizing the pulverized product (fine pulverization step) may be carried out. Further, when the particle size of the pulverized product is made uniform, a step of classifying the obtained pulverized product (classification step) may be carried out. By the above steps, toner matrix particles which are pulverized products can be obtained.

[External process]
Then, using a mixer, the obtained toner mother particles and the external additive are mixed, and the external additive is attached to the surface of the toner mother particles. The external additive contains at least specific titanium acid compound particles. Examples of the mixer include an FM mixer (manufactured by Nippon Coke Industries Co., Ltd.). In this way, the toner containing the toner particles is produced.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to the scope of the examples.

<Evaluation method of titanium acid compound particles (evaluation device)>
First, an evaluation method (evaluation device) for titanium acid compound particles will be described. A scanning electron microscope "JSM-7401F" manufactured by JEOL Ltd. and image analysis software ("WinROOF" manufactured by Mitani Shoji Co., Ltd.) were used for measuring the number average primary particle size of the titanic acid compound particles. The amount of elements in the titanic acid compound particles was measured by an inductively coupled plasma emission spectrophotometer (“SPS1200VR” manufactured by Seiko Instruments Inc.). The powder X-ray diffraction pattern of the titanium acid compound particles was measured using an X-ray diffractometer (“RINT®-TTR III” manufactured by Rigaku Co., Ltd., characteristic X-ray: Cu-Kα ray).

The relative permittivity and the number average circularity of the titanic acid compound particles were measured by the methods shown below, respectively.

[Measurement of relative permittivity]
1 g of the titanium acid compound particles were compressed under the condition of a pressure of 200 kg / cm ² for 2 minutes, and formed into disc-shaped pellets (measurement sample) having a diameter of 25 mm and a thickness of 1 mm. Next, the above-mentioned measurement sample was set in a rotary rheometer (“ARES-G2” manufactured by TA Instruments) equipped with a permittivity measuring jig (electrode) having a diameter of 25 mm. Then, using an LCR meter (“4284A Precision LCR Meter” manufactured by KeySight Technologies Co., Ltd.), a measurement sample (titanic acid compound) was used under the conditions of a measurement temperature of 25 ° C., a load of 150 g, an applied voltage of 1.0 V, and a frequency of 1.0 MHz. The relative permittivity of the particles) was obtained.

[Measurement of number average circularity]
The titanium acid compound particles were photographed with a scanning electron microscope (“JSM-7401F” manufactured by JEOL Ltd.), and the obtained image was analyzed by image analysis software (“WinROOF” manufactured by Mitani Shoji Co., Ltd.). Specifically, 100 particles were randomly selected from the titanium acid compound particles existing in the image, and the circularity of each particle (circumferential length of a circle equal to the projected area of the particle / peripheral length of the particle) was measured. .. The number average value was calculated from the measured circularity of 100 particles, and the obtained value was taken as the number average circularity of the titanium acid compound particles.

<Preparation of titanium acid compound particles>
Hereinafter, a method for preparing the titanium acid compound particles EA-1 to EA-4 and EB-1 to EB-5 will be described.

[Preparation of Titanate Compound Particles EA-1]
(Reaction preparation process)
First, the reaction preparation step will be described. After the metatitanic acid obtained by the sulfuric acid method was deironed, an aqueous sodium hydroxide solution was added to the deironed metatitanic acid to prepare a suspension having a pH of 9.0. After desulfurizing the obtained suspension, hydrochloric acid was added to the desulfurized suspension to adjust the pH of the suspension to 5.8. Next, the suspension adjusted to pH 5.8 was filtered (solid-liquid separation), the obtained solid content was washed with water, and then ion-exchanged water was added to the washed solid content to bring the Ti concentration to 2.13 mol. A / L slurry was obtained. A gelatinizing treatment was performed by adding hydrochloric acid to the obtained slurry. The pH of the slurry after the defibration treatment was 1.4. Next, the slurry after the deflocculation treatment (1.8770 mol in terms of TiO ₂ ) was put into a 3 L reaction vessel. Next, 2.1590 mol of an aqueous solution of strontium chloride (SrCl ₂ ) was charged into the reaction vessel in terms of Sr. The contents of the reaction vessel after the strontium chloride aqueous solution is charged (hereinafter, the contents of the reaction vessel are simply referred to as “container contents”) have a molar ratio of Sr to Ti (Sr / Ti) of 1. It was fifteen. Next, 0.2160 mol of an aqueous solution of lanthanum chloride (LaCl ₃ ) was charged into the reaction vessel in terms of La. The molar ratio (La / Sr) of La and Sr of the contents of the container after the aqueous solution of lanthanum chloride was added was 0.10. Next, 0.0094 mol of ferric chloride (FeCl ₃ ) was charged into the reaction vessel in terms of Fe. The molar ratio (Fe / Ti) of Fe to Ti was 0.005 in the contents of the container after the ferric chloride was added. Next, ion-exchanged water was added to the contents of the container to obtain a slurry having a Ti concentration of 0.939 mol / L.

(Reaction process)
Next, the reaction process will be described. While stirring the slurry (Ti concentration: 0.939 mol / L) obtained in the above procedure, the internal temperature of the reaction vessel was raised to 90 ° C., and then 535 mL of a sodium hydroxide aqueous solution was placed in the reaction vessel. (Concentration of NaOH: 10 mol / L) was added at a constant rate over 1 hour. Then, after raising the internal temperature of the reaction vessel to 95 ° C., the contents of the vessel were stirred for 1 hour while maintaining the internal temperature of the reaction vessel at 95 ° C. Next, the container contents were cooled to a temperature of 50 ° C., and then hydrochloric acid was added to the cooled container contents to adjust the pH of the container contents to 5.0. Next, the contents of the reaction vessel were stirred for 1 hour while the internal temperature of the reaction vessel was maintained at 50 ° C. to obtain a precipitate.

The obtained precipitate is washed by decantation, filtered (solid-liquid separation), and then the obtained solid content is dried in the air at a temperature of 120 ° C. for 10 hours to obtain a titanium acid compound containing lanthanum and iron. A powder of particle A-1 was obtained.

(Hydrophobic treatment process)
Next, the hydrophobizing treatment step will be described. 100 parts by mass of titanium acid compound particles A-1 were put into a three-necked flask equipped with a thermometer and a stirrer, and the air in the flask was replaced with nitrogen to create a nitrogen atmosphere in the flask. Subsequently, while stirring the contents of the flask, an amount suitable for advancing the reaction (specifically, hydrolysis reaction) between 15 parts by mass of isobutyltrimethoxysilane and the surface of the titanate compound particles A-1. Distilled water was sprayed into the flask. Then, while stirring the contents of the flask, the titanium acid compound particles A-1 and isobutyltrimethoxysilane were reacted for 2 hours under the condition of a temperature of 110 ° C. As a result, the titanic acid compound particles having the titanic acid compound particles A-1 (base) and the isobutyl group (specifically, the isobutyl group derived from isobutyltrimethoxysilane) imparted to the surface of the titanic acid compound particle A-1. A powder of EA-1 was obtained.

(Number average primary particle size, number average circularity, and powder X-ray diffraction pattern)
The number average primary particle diameter of the obtained titanium acid compound particles EA-1 was 30 nm. The number average circularity of the obtained titanium acid compound particles EA-1 was 0.84. The peak position of the powder X-ray diffraction pattern of the obtained titanium acid compound particles EA-1 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanate compound particles EA-1 were strontium titanate particles doped with lanthanum and iron. The number average primary particle diameter, number average circularity, and powder X-ray diffraction pattern of the titanic acid compound particles EA-1 are all the titanic acid compounds separated from the toner particles after the toner was prepared by the method described later. The same result was obtained when the powder of particle EA-1 was measured as a measurement target. The same applies to the number average primary particle diameter, number average circularity, and powder X-ray diffraction pattern of the titanium acid compound particles EA-2 to EA-4 and EB-1 to EB-5, which will be described later.

[Preparation of Titanate Compound Particles EA-2]
In the reaction preparation step, the amount of aqueous solution of lanthanum chloride used (input amount) was changed to 0.4320 mol in La conversion, and the amount of ferric chloride used (input amount) was changed to 0.0188 mol in Fe conversion. The powder of the titanic acid compound particles EA-2 was obtained by the same method as the preparation of the titanic acid compound particles EA-1 except for the modification. The titanium acid compound particles EA-2 are titanium acid compound particles having a titanium acid compound particle A-2 (base) containing lanthanum and iron and an isobutyl group imparted to the surface of the titanium acid compound particle A-2. there were. The number average primary particle diameter of the titanium acid compound particles EA-2 was 30 nm. The number average circularity of the titanium acid compound particles EA-2 was 0.92. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EA-2 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanium acid compound particles EA-2 were strontium titanate particles doped with lanthanum and iron.

[Preparation of Titanate Compound Particles EA-3]
In the reaction preparation step, an aqueous solution of barium chloride (BaCl ₂ ) (2.1590 mol in terms of Ba) was used instead of an aqueous solution of strontium chloride (2.1590 mol in terms of Sr), and the amount of the aqueous solution of lanthanum chloride used. Titanic acid compound particles EA-, except that (input amount) was changed to 0.0650 mol in La conversion and ferric chloride usage (input amount) was changed to 0.0019 mol in Fe conversion. The powder of the titanic acid compound particle EA-3 was obtained by the same method as the preparation of 1. The titanium acid compound particles EA-3 are titanium acid compound particles having a titanium acid compound particle A-3 (base) containing lanthanum and iron and an isobutyl group imparted to the surface of the titanium acid compound particle A-3. there were. The number average primary particle diameter of the titanium acid compound particles EA-3 was 30 nm. The number average circularity of the titanium acid compound particles EA-3 was 0.79. Further, the peak position of the powder X-ray diffraction pattern of the titanate compound particles EA-3 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite type crystal structure of barium titanate (base material). That is, the titanate compound particles EA-3 were barium titanate particles doped with lanthanum and iron.

[Preparation of Titanate Compound Particles EA-4]
Titanium compound particles EA, except that an aqueous solution of calcium chloride (CaCl ₂ ) (2.1590 mol in terms of Ca) was used instead of an aqueous solution of strontium chloride (2.1590 mol in Sr equivalent) in the reaction preparation step. The powder of the titanic acid compound particles EA-4 was obtained by the same method as the preparation of -1. The titanium acid compound particles EA-4 are titanium acid compound particles having a titanium acid compound particle A-4 (base) containing lanthanum and iron and an isobutyl group imparted to the surface of the titanium acid compound particle A-4. there were. The number average primary particle diameter of the titanium acid compound particles EA-4 was 30 nm. The number average circularity of the titanium acid compound particles EA-4 was 0.84. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EA-4 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of calcium titanate (base material). That is, the titanate compound particles EA-4 were calcium titanate particles doped with lanthanum and iron.

[Preparation of Titanate Compound Particles EB-1]
Titanic compound particles, except that the aqueous solution of lanthanum chloride was not used (added) in the reaction preparation step, and the amount of ferric chloride used (addition) was changed to 0.0188 mol in terms of Fe. The powder of the titanic acid compound particles EB-1 was obtained by the same method as the preparation of EA-1. The titanium acid compound particles EB-1 were titanium acid compound particles having iron-containing titanium acid compound particles B-1 (base) and isobutyl groups imparted to the surface of the titanium acid compound particles B-1. The number average primary particle diameter of the titanium acid compound particles EB-1 was 30 nm. The number average circularity of the titanium acid compound particles EB-1 was 0.78. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EB-1 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanium acid compound particles EB-1 were iron-doped strontium titanate particles.

[Preparation of Titanate Compound Particles EB-2]
In the reaction preparation step, ferric chloride was not used (added), and instead of an aqueous solution of strontium chloride (2.1590 mol in Sr conversion), an aqueous solution of barium chloride (BaCl ₂ ) (2.1590 in terms of Ba). Titanic acid by the same method as the preparation of the titanic acid compound particles EA-1, except that the molar amount) was used and the amount of the aqueous solution of lanthanum chloride used (input amount) was changed to 0.0650 mol in terms of La. A powder of compound particle EB-2 was obtained. The titanium acid compound particles EB-2 were titanium acid compound particles having lanthanum-containing titanium acid compound particles B-2 (base) and isobutyl groups imparted to the surface of the titanium acid compound particles B-2. The number average primary particle diameter of the titanium acid compound particles EB-2 was 30 nm. The number average circularity of the titanium acid compound particles EB-2 was 0.81. Further, the peak position of the powder X-ray diffraction pattern of the titanate compound particles EB-2 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite type crystal structure of barium titanate (base material). That is, the titanate compound particles EB-2 were lanthanum-doped barium titanate particles.

[Preparation of Titanate Compound Particles EB-3]
In the reaction preparation step, the amount of ferric chloride used (input amount) was changed to 0.0206 mol in terms of Fe, but the same method as the preparation of the titanium acid compound particles EA-1 was used to prepare the titanium acid compound particles EB. A powder of -3 was obtained. The titanium acid compound particles EB-3 are titanium acid compound particles having a titanium acid compound particle B-3 (base) containing lantern and iron and an isobutyl group imparted to the surface of the titanium acid compound particle B-3. there were. The number average primary particle diameter of the titanium acid compound particles EB-3 was 30 nm. The number average circularity of the titanium acid compound particles EB-3 was 0.84. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EB-3 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanate compound particles EB-3 were strontium titanate particles doped with lanthanum and iron.

[Preparation of Titanate Compound Particles EB-4]
In the reaction preparation step, ferric chloride was not used (added), the amount of strontium chloride aqueous solution used (added amount) was changed to 1.8770 mol in terms of Sr, and the use of an aqueous solution of lanthanum chloride. The powder of the titanic acid compound particles EB-4 was obtained by the same method as the preparation of the titanic acid compound particles EA-1 except that the amount (input amount) was changed to 0.3380 mol in terms of La. The titanium acid compound particles EB-4 were titanium acid compound particles having lanthanum-containing titanium acid compound particles B-4 (base) and isobutyl groups imparted to the surface of the titanium acid compound particles B-4. The number average primary particle diameter of the titanium acid compound particles EB-4 was 30 nm. The number average circularity of the titanium acid compound particles EB-4 was 0.85. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EB-4 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanate compound particles EB-4 were lanthanum-doped strontium titanate particles.

[Preparation of Titanate Compound Particles EB-5]
In the reaction preparation step, the amount of the aqueous solution of lanthanum chloride (input amount) was changed to 0.0432 mol in terms of La, but the same method as the preparation of the titanium acid compound particles EA-1 was used to prepare the titanium acid compound particles EB. A powder of -5 was obtained. The titanium acid compound particles EB-5 are titanium acid compound particles having a titanium acid compound particle B-5 (base) containing lanthanum and iron and an isobutyl group imparted to the surface of the titanium acid compound particle B-5. there were. The number average primary particle diameter of the titanium acid compound particles EB-5 was 30 nm. The number average circularity of the titanium acid compound particles EB-5 was 0.78. The peak position of the powder X-ray diffraction pattern of the titanate compound particles EB-5 coincided with the peak position of the powder X-ray diffraction pattern of the perovskite-type crystal structure of strontium titanate (base material). That is, the titanate compound particles EB-5 were strontium titanate particles doped with lanthanum and iron.

Table 1 shows the amount of iron, the amount of lanthanum, and the relative permittivity for each of the titanium acid compound particles EA-1 to EA-4 and EB-1 to EB-5. In Table 1, the amount of iron and the amount of lanthanum are both amounts (unit: mass%) with respect to the total mass of the titanium acid compound particles. Further, in Table 1, "-" indicates that it was less than the detection limit of the inductively coupled plasma emission spectrophotometer used for the measurement (0.01 mass ppm with respect to the total mass of the titanic acid compound particles). The amount of iron, the amount of lantern, and the relative permittivity of each titanic acid compound particle are measured by measuring the powder of each titanic acid compound particle separated from the toner particle after preparing the toner by the method described later. The same result was obtained when measured as a subject.

<Making toner>
Hereinafter, a method for producing the toners TA-1 to TA-5 and TB-1 to TB-6 will be described.

[Preparation of toner TA-1]
(Polyester resin synthesis process)
1.0 mol of bisphenol A ethylene oxide adduct (average number of moles of ethylene oxide added: 2 mol), 4.5 mol of terephthalic acid, 0.5 mol of trimellitic anhydride, and 4.0 g of dibutyltin oxide. , Placed in a reaction vessel. Subsequently, the contents of the container were reacted at a temperature of 230 ° C. for 8 hours under atmospheric pressure in a nitrogen atmosphere. Then, the pressure in the container was reduced to 8.3 kPa, and the unreacted components were distilled off under reduced pressure to obtain a polyester resin (binding resin) having a softening point (Tm) of 120 ° C.

(Preparation process of toner matrix particles)
100 parts by mass of polyester resin obtained by the above synthesis step, 4 parts by mass of colorant (CI Pigment Blue 15: 1, manufactured by Sanyo Dye Co., Ltd.), and carnauba wax as a release agent (Kato Co., Ltd.) FM mixer with 10 parts by mass of "Carnauba Wax No. 1" manufactured by Yokou and 3 parts by mass of a positive charge control agent ("Acrybase (registered trademark) FCA-201-PS" manufactured by Fujikura Kasei Co., Ltd.) After being charged into (“FM-20B” manufactured by Nippon Coke Industries Co., Ltd.), these materials were mixed for 4 minutes under the condition of a rotation speed of 2000 rpm.

Subsequently, the obtained mixture was melt-kneaded using a twin-screw extruder (“TEM45” manufactured by Toshiba Machine Co., Ltd.) under the condition of a temperature of 150 ° C. Then, the obtained kneaded product was cooled. Subsequently, the cooled kneaded product was roughly pulverized using a pulverizer (“Fezamil (registered trademark) 350 × 600 type” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized using a jet crusher (“Jet Mill IDS-2” manufactured by Nippon Pneumatic Industries Co., Ltd.). Subsequently, the obtained finely pulverized product was classified using a classification machine (“Elbow Jet EJ-LABO type” manufactured by Nittetsu Mining Co., Ltd.). As a result, toner mother particles having a volume median diameter (D ₅₀ ) of 7 μm were obtained.

(External process)
100 parts by mass of toner mother particles (toner mother particles obtained in the above preparation step), 0.5 parts by mass of titanoic acid compound particles EA-1, and 1.5 parts by mass of hydrophobic silica particles (Nihon Aerosil) "AEROSIL (registered trademark) RA-200H" manufactured by Co., Ltd.) and 1.0 parts by mass of conductive titanium oxide particles ("EC-100" manufactured by Titanium Industry Co., Ltd.) are used in an FM mixer (Nippon Coke Industry Co., Ltd.). It was put into the manufactured "FM-10B"). Next, using the above FM mixer, the toner mother particles and the external additive (titanate compound particles EA-1, hydrophobic silica particles and conductive titanium oxide particles) were added under the conditions of a rotation speed of 3500 rpm and a jacket temperature of 20 ° C. It was mixed for 15 minutes. As a result, the entire amount of the external additive was adhered to the surface of the toner matrix particles.

Subsequently, the obtained powder was sieved using a 200 mesh (opening 75 μm) sieve. As a result, a positively charged toner TA-1 was obtained.

[Preparation of toners TA-2 to TA-5 and TB-1 to TB-6]
Positively charged toners TA-2 to TA-5 and TB were prepared in the same manner as the toner TA-1, except that the types of the titanic acid compound particles and the amount of the particles charged therein were as shown in Table 2 described later. -2 to TB-6 were prepared, respectively. In addition, the positively charged toner TB-1 was produced by the same method as that for producing the toner TA-1, except that the titanium acid compound particles EA-1 were not used (charged). In Table 2, the “input amount” in the column of the titanium acid compound particles is the amount (unit: parts by mass) of each titanium acid compound particles input to the FM mixer with respect to 100 parts by mass of the toner mother particles. .. Further, in Table 2, "-" in the column of the titanium acid compound particles means that the titanium acid compound particles were not used.

<Toner evaluation method>
Hereinafter, the evaluation method of the toners TA-1 to TA-5 and TB-1 to TB-6 will be described.

[Preparation of two-component developer]
(Carrier manufacturing process)
As a carrier core, a ferrite core (“EF-35B” manufactured by Powdertech Co., Ltd., medium volume diameter (D ₅₀ ): 35 μm) was prepared. A heat-curable silicone resin (“KR-220L” manufactured by Shin-Etsu Chemical Industry Co., Ltd.) diluted with toluene to a solid content concentration of 17% by mass as a liquid (coating liquid) containing the raw material of the coat layer that coats the carrier core. , Curing start temperature: 170 ° C.) was prepared. 1000 parts by mass of the ferrite core was put into a rolling fluidized bed coating device (“Spiracoater (registered trademark) SP-25” manufactured by Okada Seiko Co., Ltd.), and the coating liquid was directed toward the ferrite core while flowing the ferrite core. 120 parts by mass was sprayed. Subsequently, the ferrite core covered with the coating liquid was heat-treated at a temperature of 200 ° C. for 2 hours to obtain carrier particles in which the entire surface of the ferrite core was covered with a coating layer (layer composed of silicone resin). A powder (carrier) was obtained.

(Mixing process of carrier and toner)
30 parts by mass of the carrier obtained by the above-mentioned manufacturing step and 10 parts by mass of the toner (evaluation target: any of toners TA-1 to TA-5 and TB-1 to TB-6) are 30 parts by mass using a ball mill. Mixing for minutes prepared a two-component developer for evaluation.

[Confirmation of image defects due to polishing of the surface of the photoconductor drum]
As the evaluation machine, a color multifunction device (“TASKalfa 3252ci” manufactured by Kyocera Document Solutions Co., Ltd.) was used. The evaluation machine was provided with an organic photoconductor drum (a photoconductor drum containing a photosensitive layer containing an organic photoconductor). The two-component developer prepared as described above is put into the cyan developing apparatus of the evaluation machine, and a replenishing toner (evaluation target: toner TA-1 to TA-5 or TB-1 to TB-6) is used. ) Was put into the cyan toner container of the above evaluation machine.

Next, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, 20,000 sheets of images having a printing rate of 5% were continuously printed on printing paper (A4 size) using the above evaluation machine. Then, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, an image having a printing rate of 5% was printed on one printing paper (A4 size), and the printed image was visually observed. Then, the image defect (streak) caused by the polishing of the surface of the photoconductor drum was determined according to the following criteria. If the judgment is A, it is evaluated as "particularly good", if the judgment is B, it is evaluated as "good", and if the judgment is C, it is evaluated as "not good".

(Criteria)
A: No muscle was observed.
B: Some streaks were observed, but there was no problem in practical use.
C: Muscles were observed, and the observed muscles were at a practically problematic level.

[Evaluation in high temperature and high humidity environment]
As the evaluation machine, a color multifunction device (“TASKalfa 3252ci” manufactured by Kyocera Document Solutions Co., Ltd.) was used. In a high temperature and high humidity environment with a temperature of 32.5 ° C and a humidity of 80% RH, the two-component developer prepared as described above and the replenishing toner (evaluation targets: toners TA-1 to TA-5 and TB-1 to 1). (Any of TB-6) was allowed to stand for 24 hours. Next, the stationary two-component developer was charged into the cyan developing apparatus of the evaluation machine, and the stationary replenishing toner was charged into the cyan toner container of the evaluation machine.

Next, in a high-temperature and high-humidity environment with a temperature of 32.5 ° C. and a humidity of 80% RH, an image having a printing rate of 5% is printed on one printing paper (A4 size) using the above-mentioned evaluation machine, and the evaluation image A Got Immediately after obtaining the evaluation image A, the two-component developer was taken out from the cyan developing apparatus of the evaluation machine. Next, in a high-temperature and high-humidity environment with a temperature of 32.5 ° C. and a humidity of 80% RH, the amount of charge (unit: μC / g) of the toner contained in the two-component developer taken out was measured by a Q / m meter (manufactured by Trek). It was measured using "MODEL 210HS-2A"). Hereinafter, the amount of charge measured here will be referred to as E1. When E1 was 15.0 μC / g or more, it was evaluated as “good”. On the other hand, when E1 was less than 15.0 μC / g, it was evaluated as “not good”.

Further, the image density (ID) of the blank portion of the printed evaluation image A is measured using a reflection densitometer (“SpectroEye®” manufactured by X-Rite), and the fog density (FD) is measured. Calculated. The fog density (FD) corresponds to a value obtained by subtracting the image density (ID) of the base paper (unprinted paper) from the image density (ID) of the blank portion of the evaluation image A.

When the fog concentration (FD) was 0.005 or less, it was evaluated that "the occurrence of fog was particularly suppressed". When the fog concentration (FD) was more than 0.005 and 0.010 or less, it was evaluated that "the occurrence of fog could be suppressed". When the fog concentration (FD) exceeded 0.010, it was evaluated as "the occurrence of fog could not be suppressed".

[Evaluation in low temperature and low humidity environment]
(Initial charge amount)
As the evaluation machine, a color multifunction device (“TASKalfa 3252ci” manufactured by Kyocera Document Solutions Co., Ltd.) was used. In a low temperature and low humidity environment with a temperature of 10 ° C and a humidity of 10% RH, the two-component developer prepared as described above and the replenishing toner (evaluation targets: toners TA-1 to TA-5 and TB-1 to TB-6). ) Was allowed to stand for 12 hours. Next, the stationary two-component developer was charged into the cyan developing apparatus of the evaluation machine, and the stationary replenishing toner was charged into the cyan toner container of the evaluation machine.

Next, in a low-temperature and low-humidity environment with a temperature of 10 ° C. and a humidity of 10% RH, an image having a printing rate of 2% is printed on one printing paper (A4 size) using the above-mentioned evaluation machine, and then for cyan of the above-mentioned evaluation machine. The two-component developer was taken out from the developing device. Next, in a low-temperature and low-humidity environment with a temperature of 10 ° C. and a humidity of 10% RH, the amount of charge (unit: μC / g) of the toner contained in the extracted two-component developer was measured by a Q / m meter (Trek's “MODEL 210HS”). -2A ") was used for measurement. Hereinafter, the charge amount (initial charge amount) measured here will be referred to as E2. When E2 was 45.0 μC / g or less, it was evaluated as “good”. On the other hand, when E2 exceeded 45.0 μC / g, it was evaluated as “not good”.

(Presence / absence of black spots, image density, and charge amount after continuous printing)
As the evaluation machine, a color multifunction device (“TASKalfa 3252ci” manufactured by Kyocera Document Solutions Co., Ltd.) was used. In a low temperature and low humidity environment with a temperature of 10 ° C and a humidity of 10% RH, the two-component developer prepared as described above and the replenishing toner (evaluation targets: toners TA-1 to TA-5 and TB-1 to TB-6). ) Was allowed to stand for 12 hours. Next, the stationary two-component developer was charged into the cyan developing apparatus of the evaluation machine, and the stationary replenishing toner was charged into the cyan toner container of the evaluation machine.

Then, in a low temperature and low humidity environment of a temperature of 10 ° C. and a humidity of 10% RH, an image having a printing rate of 2% was continuously printed on 20,000 sheets of printing paper (A4 size) using the above evaluation machine. Next, a pattern image including a solid image was printed on one printing paper (A4 size) under a low temperature and low humidity environment of a temperature of 10 ° C. and a humidity of 10% RH to obtain an evaluation image B. Immediately after obtaining the evaluation image B, the two-component developer was taken out from the cyan developing apparatus of the evaluation machine. Next, in a low-temperature and low-humidity environment with a temperature of 10 ° C. and a humidity of 10% RH, the amount of charge (unit: μC / g) of the toner contained in the extracted two-component developer was measured by a Q / m meter (Trek's “MODEL 210HS”). -2A ") was used for measurement. Hereinafter, the charge amount measured here (charge amount after continuous printing) is referred to as E3. When E3 was 45.0 μC / g or less, it was evaluated as “good”. On the other hand, when E3 exceeded 45.0 μC / g, it was evaluated as “not good”.

In addition, the printed evaluation image B was visually observed to confirm the presence or absence of image defects (black spots) due to dielectric breakdown of the photoconductor drum.

Further, the image density (ID) of the printed portion of the printed evaluation image B was measured using a reflection densitometer (“SpectroEye®” manufactured by X-Rite). If the image density (ID) is 1.20 or more, it is evaluated as "particularly good", and if the image density (ID) is 1.00 or more and less than 1.20, it is evaluated as "good", and the image density (ID) If is less than 1.00, it was evaluated as "not good".

For each of the toners TA-1 to TA-5 and TB-1 to TB-6, the type of the titanic compound particles, the input amount of the titanic acid compound particles, and the judgment result of the image defect due to the polishing of the surface of the photoconductor drum Is shown in Table 2. Table 3 shows the evaluation results of the toners TA-1 to TA-5 and TB-1 to TB-6 in a high temperature and high humidity environment and the evaluation results in a low temperature and low humidity environment.

As shown in Tables 1 and 2, in the toners TA-1 to TA-5, the external additive contained titanium acid compound particles doped with lantern and iron as the external additive particles. In the toners TA-1 to TA-5, the amount of lanthanum was 1.50% by mass or more with respect to the total mass of the titanium acid compound particles. In the toners TA-1 to TA-5, the amount of iron was 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the titanoic acid compound particles.

As shown in Table 3, the fog concentration (FD) of the toners TA-1 to TA-3 and TA-5 was 0.005 or less. Therefore, the toners TA-1 to TA-3 and TA-5 were able to particularly suppress the occurrence of fog. With the toner TA-4, the fog concentration (FD) was more than 0.005 and 0.010 or less. Therefore, the toner TA-4 was able to suppress the occurrence of fog.

As shown in Table 2, in the toners TA-1 to TA-5, the determination result of the image defect due to the polishing of the surface of the photoconductor drum was A (particularly good) or B (good). As shown in Table 3, with the toners TA-1 to TA-5, no image defect (black spot) due to dielectric breakdown of the photoconductor drum was confirmed. With the toners TA-1 to TA-5, the image density (ID) was 1.20 or more (particularly good). From the above evaluation results, it was shown that the toners TA-1 to TA-5 can form a high-quality image even after printing a large number of sheets.

As shown in Tables 1 and 2, in the toner TB-1, the external additive did not contain the titanium acid compound particles. In the toners TB-2 and TB-6, the amount of lanthanum was less than 1.50% by mass with respect to the total mass of the titanium acid compound particles. In the toners TB-3 and TB-5, the amount of iron was less than 10 mass ppm with respect to the total mass of the titanium acid compound particles. In the toner TB-4, the amount of iron exceeded 100 mass ppm with respect to the total mass of the titanium acid compound particles.

As shown in Table 2, with the toners TB-2 and TB-6, the determination result of image defect due to polishing of the surface of the photoconductor drum was C (not good). As shown in Table 3, the image density (ID) of the toner TB-1 was less than 1.00 (not good). With the toners TB-3 and TB-5, image defects (black spots) due to dielectric breakdown of the photoconductor drum were confirmed.

As shown in Table 3, the fog concentration (FD) of the toner TB-4 exceeded 0.010. Therefore, the toner TB-4 could not suppress the occurrence of fog.

From the above results, it was shown that the toner according to the present invention can form a high-quality image even after printing a large number of sheets while suppressing the occurrence of fog.

The toner according to the present invention can be used for forming an image in, for example, a multifunction device or a printer.

10: Toner particles 11: Toner mother particles 12: Specific titanium acid compound particles (titanate compound particles)

Claims (9)

Toner containing toner particles
The toner particles include a toner mother particle containing a binder resin and an external additive adhering to the surface of the toner mother particle.
The external additive contains titanium acid compound particles doped with lantern and iron as external additive particles.
The amount of the lanthanum is 1.50% by mass or more with respect to the total mass of the titanium acid compound particles.
The amount of iron is 10 mass ppm or more and 100 mass ppm or less with respect to the total mass of the titanic acid compound particles. The toner according to claim 1, wherein the number average circularity of the titanium acid compound particles is 0.79 or more and 1.00 or less. The titanate compound particles are strontium titanate particles doped with the lantern and the iron, barium titanate particles doped with the lantern and the iron, or titanium acid doped with the lantern and the iron. The toner according to claim 1 or 2, which is a calcium particle. The toner according to any one of claims 1 to 3, wherein the amount of the titanium acid compound particles is 0.1 part by mass or more and 1.2 parts by mass or less with respect to 100 parts by mass of the toner mother particles. The toner according to any one of claims 1 to 4, wherein the amount of the lanthanum is 15.00% by mass or less with respect to the total mass of the titanium acid compound particles. The toner according to any one of claims 1 to 5, wherein the number average primary particle diameter of the titanium acid compound particles is 20 nm or more and 80 nm or less. The toner according to any one of claims 1 to 6, wherein the titanium acid compound particles have a relative permittivity of 100 or more and 1200 or less. The toner according to any one of claims 1 to 7, wherein the surface of the titanium acid compound particles is hydrophobized. The toner according to claim 8, wherein the surface of the titanium acid compound particles has an alkyl group having 3 to 8 carbon atoms.

Images