JP2016045351A - Toner for electrostatic charge image development, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that suppresses an increase in rotational load (increase in torque) of an image holding body.SOLUTION: A toner for electrostatic charge image development includes toner particles, and silica particles that are adhered to the surface of the toner particles, have the surface treated with oil, and have the standard deviation σ of the amount of free oil of 0.5 or less.SELECTED DRAWING: None

Description

  The present invention relates to an electrostatic charge image developing toner, an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method.

  Methods for visualizing image information through an electrostatic charge image, such as electrophotography, are currently used in various fields. In electrophotography, an electrostatic image formed on an image carrier by a charging process and an exposure process is developed with a developer containing toner, and visualized through a transfer process and a fixing process.

  As the above toner, those containing silica particles as an external additive are known. For example, the following toner has been proposed.

  For example, Patent Document 1 discloses that "toner particles and silica particles having an average primary particle size treated with silicone oil of 50 nm to 150 nm and a free oil amount of 0.1% by mass to 3% by mass. An electrostatic charge image developing toner containing "is disclosed.

  Patent Document 2 discloses “electrostatic image developing toner containing toner particles, at least silica particles treated with silicone oil and silica particles not treated with silicone oil”.

  Patent Document 3 states that “the average particle size of primary particles in which an external additive is treated with methylhydrogen silicone oil in an electrophotographic toner comprising at least a binder resin, a colorant, and an external additive is 100 nm or less. And an electrophotographic toner having a release rate of methyl hydrogen silicone oil of 30% or less.

  Patent Document 4 states that “a magnetic toner comprising at least a binder resin and a magnetic material, the magnetic toner being treated with silicone oil and containing inorganic fine particles having a silicone oil release rate of 10 to 70%. An electrophotographic toner is disclosed.

JP 2009-098194 A JP 2002-207315 A JP 2002-268272 A JP 2003-107772 A

  An object of the present invention is to provide a toner for developing an electrostatic image that suppresses an increase in rotational load (hereinafter also referred to as “torque up”) of an image carrier.

  The above problem is solved by the following means.

The invention according to claim 1
Toner particles,
Silica particles adhering to the surface of the toner particles, the surface of which is treated with oil, and the standard deviation σ of the amount of free oil is 0.5 or less,
A toner for developing an electrostatic charge image.

The invention according to claim 2
The toner for developing an electrostatic image according to claim 1, wherein the silica particles are silica particles having a volume average particle diameter of more than 50 nm and less than 200 nm.

The invention according to claim 3
The electrostatic image developing toner according to claim 1, wherein the silica particles are silica particles that are surface-treated with oil in supercritical carbon dioxide.

The invention according to claim 4
The electrostatic image developing toner according to claim 3, wherein the silica particles are silica particles surface-treated with a mixture containing a silane hydrophobizing agent together with the oil.

The invention according to claim 5
An electrostatic charge image developer containing the electrostatic charge image developing toner according to claim 1.

The invention according to claim 6
Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 4,
A toner cartridge to be attached to and detached from the image forming apparatus.

The invention according to claim 7 provides:
A developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus.

The invention according to claim 8 provides:
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising:

The invention according to claim 9 is:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A cleaning step of cleaning the surface of the image carrier with a cleaning blade;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising:

According to the first aspect of the present invention, there is provided an electrostatic image developing toner that suppresses torque increase as compared with a case where the standard deviation σ of the free oil amount of silica particles exceeds 0.5.
According to the second aspect of the present invention, there is provided an electrostatic image developing toner that suppresses torque increase as compared with the case where the volume average particle diameter of silica particles is 50 nm or less.
According to the third aspect of the invention, there is provided an electrostatic image developing toner that suppresses torque increase as compared with the case where silica particles are surface-treated with oil in an air atmosphere.
According to the fourth aspect of the present invention, there is provided an electrostatic image developing toner that suppresses torque increase as compared with the case where silica particles are surface-treated with a mixture containing oil and toluene.

  According to the invention of claim 5, 6, 7, 8, or 9, the torque is increased as compared with the case where a toner for developing an electrostatic charge image in which the standard deviation σ of the free oil amount of silica particles exceeds 0.5 is applied. An electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method that suppresses the above are provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

Embodiments of the present invention will be described in detail below.
<Toner for electrostatic image development>
The electrostatic image developing toner according to the present embodiment (hereinafter sometimes simply referred to as “toner”) includes toner particles and silica particles attached to the surface of the toner particles. That is, the silica particles are externally added to the toner particles as an external additive.
The silica particles are silica particles which are surface-treated with oil and have a standard deviation σ of the amount of free oil of 0.5 or less.

  Conventionally, it is known to use silica particles surface-treated with oil as an external additive for toner. The silica particles surface-treated with oil supply oil to the contact portion (hereinafter also referred to as “cleaning portion”) between the cleaning blade and the image carrier, and a toner reservoir (hereinafter referred to as “toner dam”) formed in the cleaning portion. The cohesive force of the toner is increased. Thereby, the cleaning property by the cleaning blade is enhanced.

  However, when silica particles surface-treated with oil are used as an external additive for toner, a torque increase (an increase in the rotational load of the image carrier) may occur. In particular, when image formation is performed at a high process speed (recording medium conveyance speed) of 350 mm / sec or more, a torque increase is likely to occur.

  This is presumed to be caused by uneven surface treatment of the oil on the silica particles. Specifically, when silica particles having uneven surface treatment of oil are used as an external additive for toner, uneven supply of oil at the cleaning unit occurs. Further, due to uneven supply of oil, unevenness of toner cohesive force in the axial direction of the image carrier is also generated in the toner dam. This uneven toner cohesion force fluctuates the pressure applied to the cleaning blade in the axial direction of the image carrier, and causes distortion of the cleaning blade. It is estimated that torque increases due to the distortion of the cleaning blade.

Therefore, in the toner according to the exemplary embodiment, silica particles that are surface-treated with oil and have a standard deviation σ of the amount of free oil of 0.5 or less are used as silica particles as an external additive. The standard deviation σ of the amount of free oil being 0.5 or less indicates a state in which the silica particles are surface-treated in a state that is nearly uniform with the oil. That is, it is considered that when silica particles having a standard deviation σ of the amount of free oil of 0.5 or less are used as an external additive for the toner, the supply of oil in the cleaning unit is almost uniform. When the oil is supplied in a nearly uniform state, unevenness in the cohesive force of the toner, which causes distortion of the cleaning blade, is suppressed in the toner dam.
For this reason, the toner according to the present embodiment suppresses torque increase (an increase in the rotational load of the image holding member).

  Here, in order to set the standard deviation σ of the free oil amount of the silica particles to 0.5 or less, the silica particles are preferably surface-treated with oil in supercritical carbon dioxide. Details thereof will be described in the silica particle production method described later.

Hereinafter, each component of the toner according to the exemplary embodiment will be described in detail.
The toner according to the exemplary embodiment includes toner particles and an external additive.

(Toner particles)
The toner particles include, for example, a binder resin. The toner particles may contain other additives such as a colorant and a release agent as necessary.

-Binder resin-

-Binder resin-
Examples of the binder resin include styrenes (eg, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (eg, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid). n-butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (for example, acrylonitrile, Methacrylonitrile, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, etc.) Emissions, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
As the binder resin, for example, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, non-vinyl resin such as modified rosin, a mixture of these with the vinyl resin, or these Examples also include a graft polymer obtained by polymerizing a vinyl monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of the polyester resin include known amorphous polyester resins. A polyester resin may use a crystalline polyester resin together with an amorphous polyester resin. However, the crystalline polyester resin is preferably used in the range of 2 mass% to 40 mass% (preferably 2 mass% to 20 mass%) with respect to the total binder resin.

The “crystallinity” of the resin means that it has a clear endothermic peak in differential scanning calorimetry (DSC) rather than a stepwise endothermic amount change. Specifically, the temperature rise rate is 10 (° C. / Min) indicates that the half-value width of the endothermic peak is 10 ° C. or less.
On the other hand, “amorphous” of the resin means that the half width exceeds 10 ° C., shows a stepwise endothermic change, or does not show a clear endothermic peak.

-Amorphous polyester resin As an amorphous polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as an amorphous polyester resin, a commercial item may be used and what was synthesize | combined may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (eg, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.) Alicyclic dicarboxylic acids (for example, cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (for example, having 1 or more carbon atoms) 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, having 1 to 5 carbon atoms) alkyl esters.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K-1987 “Method for Measuring Transition Temperature of Plastics”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the amorphous polyester resin is preferably from 5,000 to 1,000,000, more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed with a THF solvent using a Tosoh GPC / HLC-8120GPC as a measuring device and a Tosoh column / TSKgel SuperHM-M (15 cm). The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

The amorphous polyester resin can be obtained by a known production method. Specifically, for example, the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation.
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.

Crystalline polyester resin Examples of the crystalline polyester resin include a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol. In addition, as a crystalline polyester resin, a commercial item may be used and what was synthesize | combined may be used.
Here, since the crystalline polyester resin easily forms a crystal structure, a polycondensate using a polymerizable monomer having a linear aliphatic group is preferable to a polymerizable monomer having an aromatic group.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid. Acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acid (eg phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid) Dibasic acids such as acids), anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent carboxylic acid include aromatic carboxylic acids (for example, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), these Examples thereof include anhydrides and lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof.
As the polyvalent carboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, linear aliphatic diols having a main chain portion having 7 to 20 carbon atoms). Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,14-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable as the aliphatic diol.
The polyhydric alcohol may be used in combination with a diol and a trivalent or higher alcohol having a crosslinked structure or a branched structure. Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

  Here, the polyhydric alcohol may have an aliphatic diol content of 80 mol% or more, and preferably 90 mol% or more.

The melting temperature of the crystalline polyester resin is preferably 50 ° C. or higher and 100 ° C. or lower, more preferably 55 ° C. or higher and 90 ° C. or lower, and further preferably 60 ° C. or higher and 85 ° C. or lower.
The melting temperature is determined from the “melting peak temperature” described in the method for determining the melting temperature of JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC).

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

  The crystalline polyester resin can be obtained by, for example, a well-known manufacturing method, similarly to the amorphous polyester resin.

  The content of the binder resin is, for example, preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, and more preferably 60% by weight to 85% by weight with respect to the entire toner particles. Further preferred.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, or acridine series, xanthene series, azo series Various dyes such as benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole Can be mentioned.
A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.

  The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less with respect to the entire toner particles.

-Release agent-
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. And so on. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in JIS K-1987 “Method for measuring the transition temperature of plastics”.

  The content of the release agent is, for example, preferably 1% by mass to 20% by mass and more preferably 5% by mass to 15% by mass with respect to the entire toner particles.

-Other additives-
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core / shell structure toner particles include, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a binder resin. It is good to be comprised with the comprised coating layer.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

The various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter). The
In the measurement, 0.5 mg to 50 mg of a measurement sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is measured using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, a particle size that is 50% cumulative is defined as a volume average particle size D50v, a cumulative number average particle size D50p, and a particle size that is 84% cumulative is defined as a volume particle size D84v and a number particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following formula.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and is calculated as follows. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

(External additive)
As the external additive, at least silica particles which are surface-treated with oil and have a standard deviation σ of the amount of free oil of 0.5 or less are applied.

The silica particles may be silica, that is, particles containing SiO ₂ as a main component, and may be crystalline or amorphous. The silica particles may be particles produced from a silicon compound such as water glass or alkoxysilane, or may be particles obtained by pulverizing quartz.
Specific examples of the silica particles include sol-gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, famed silica particles obtained by a gas phase method, and fused silica particles. Among these, sol-gel silica particles are preferable. .

  The standard deviation σ of the amount of free oil in the silica particles is 0.5 or less, and 0.3 or less is more preferable from the viewpoint of suppressing torque increase.

  The amount of free oil in the silica particles is preferably 5% by mass or more and 10% by mass or less, and more preferably 6% by mass or more and 8% by mass or less from the viewpoint of improving the cleaning property and suppressing the decrease in the fluidity of the toner.

The amount of free oil is measured by the following method.
First, 2 g of the target toner was added to 40 ml of an aqueous solution of 0.2% by mass of a surfactant (polyoxyethylene (10) octylphenyl ether having a polyoxyethylene polymerization degree of 10 manufactured by Wako Pure Chemical Industries, Ltd.). Then, the toner is dispersed so as to get wet with the aqueous solution. In this state, an ultrasonic homogenizer US300T (manufactured by Nippon Seiki Seisakusho) is used, and ultrasonic vibration with an output of 20 W and a frequency of 20 kHz is applied for 1 minute to desorb the silica particles from the toner particles.
Thereafter, the toner particles were separated under conditions of 3000 rpm × 7 minutes through a 50 ml centrifuge with a sedimentation tube (compact cooling high-speed centrifuge Model M160 IV, manufactured by Sakuma Seisakusho). Then, after removing the toner particles from the supernatant containing the separated toner particles with a membrane filter having a pore size of 5 μm (Nippon Millipore FHLP02500), the pore size is further 0.22 μm (GSEP047S0) and 0.025 μm (VSWP02500). The toner particles were removed with a membrane filter. Thereafter, the filtrate from which the toner particles were removed was dried. Thereby, the silica particle used as a measuring object is extract | collected. When the sample amount of silica particles necessary for measurement cannot be recovered, the same operation is repeated until the sample amount required for measurement can be recovered.

Next, NMR (Nuclear Magnetic Resonance) measurement is performed on the collected silica particles. Specifically, the amount of free oil was determined by performing proton NMR measurement using AL-400 (magnetic field: 9.4T (H nucleus 400 MHz)) manufactured by JEOL. Specifically, a sample tube (diameter 5 mm) made of zirconia is filled with a sample, deuterated chloroform solvent, and TMS (tetramethylsilicon) as a reference substance. Set this sample tube, and measure, for example, frequency: Δ87 kHz / 400 MHz (= Δ20 ppm), measurement temperature: 25 ° C., number of integrations: 16 times, resolution 0.24 Hz (32000 points), from the peak intensity derived from oil Convert the amount of free oil using a calibration curve. In addition, the said measurement is performed after performing the NMR measurement of an untreated inorganic oxide particle and oil (waves about 5 level amount), and creating the analytical curve of the amount of free oil and NMR peak intensity.
And the measurement of the amount of free oil by said NMR measurement is performed 10 times, and let the average value be the value of the amount of free oil. Further, the standard deviation of the free oil amount is obtained from the measurement of each free oil amount.

The volume average particle diameter of the silica particles is, for example, 300 nm or less, preferably more than 50 nm and less than 200 nm, more preferably 100 nm or more and less than 150 nm.
In particular, when the volume average particle diameter of the silica particles exceeds 50 nm, the silica particles are easily released from the toner particles. The liberated silica particles roll in the cleaning unit, thereby reducing the frictional force between the image carrier and the cleaning blade. For this reason, the torque increase is easily suppressed.
On the other hand, when the volume average particle diameter of the silica particles is less than 200 nm, the silica particles are prevented from being excessively liberated from the toner particles, and a decrease in toner fluidity is easily suppressed.

  The volume average particle diameter of the silica particles was obtained by observing 100 primary particles of the sol-gel silica after externally adding the sol-gel silica to the toner particles with an SEM (Scanning Electron Microscope) apparatus and analyzing the primary particles. The 50% diameter (D50v) in the cumulative frequency of the equivalent circle diameter is measured by this method.

  The external addition amount (addition amount) of the silica particles is, for example, preferably from 0.3% by mass to 15% by mass, and preferably from 0.5% by mass to 10% by mass with respect to the total mass of the toner particles.

-Manufacturing method of silica particles-
The silica particles are preferably obtained by subjecting the standard deviation σ of the amount of free oil to the above range, and then subjecting the silica particles to surface treatment with oil in supercritical carbon dioxide after production. That is, the silica particles are preferably silica particles that have been surface-treated with oil in supercritical carbon dioxide.

  Hereinafter, a method for producing silica particles that are surface-treated with oil in supercritical carbon dioxide (hereinafter, also simply referred to as “silica particle production method”) will be described in detail.

  The method for producing silica particles has a surface treatment step of treating the silica particles with oil in supercritical carbon dioxide.

  In the method for producing silica particles, silica particles that have been surface-treated in a nearly uniform state with oil are obtained by surface treatment with oil in supercritical carbon dioxide. That is, silica particles having a standard deviation σ of the free oil amount satisfying the above range are obtained. The reason for this is not clear, but is presumed to be as follows.

When the surface of the silica particles is surface-treated with oil, if it is performed in supercritical carbon dioxide, the oil is dissolved in the supercritical carbon dioxide. Since supercritical carbon dioxide has a characteristic that the interfacial tension is extremely low, the oil diffuses in supercritical carbon dioxide in a state dissolved in supercritical carbon dioxide. For this reason, even if it is oil with comparatively high viscosity, it adheres in the state close | similar to the whole surface of a silica particle uniformly. In addition to this, the diffused oil, along with supercritical carbon dioxide, diffuses to the depth of the pores on the surface of the silica particles and easily reaches. Thereby, the surface treatment is performed not only on the surface of the silica particles but also deep in the hole.
For this reason, when the surface of silica particles is surface-treated with oil in supercritical carbon dioxide, surface treatment in a nearly uniform state is realized.

  In addition, since oil diffuses in supercritical carbon dioxide, the oil contacts the entire surface of the silica particles, that is, the oil is interposed between the silica particles. Aggregation hardly occurs.

Here, the sol-gel silica particles (silica particles obtained by the sol-gel method) have many silanol groups on the surface and inside the pores compared to fumed silica particles obtained by the gas phase method and fused silica particles, Although aggregation tends to occur and the generation of coarse powder tends to occur, even if sol-gel silica particles are applied as the silica particles to be surface-treated, the generation of coarse powder is difficult to occur.
The silica particles subjected to the surface treatment are not limited to sol-gel silica particles, and may be aqueous colloidal silica particles, alcoholic silica particles, fumed silica particles obtained by a gas phase method, and fused silica particles.

  Hereinafter, the details of the surface treatment process will be described.

-Surface treatment process-
In the surface treatment step, for example, untreated silica particles are introduced into a closed reactor. Next, after supercritical carbon dioxide is introduced into the hermetic container, oil is added in a state where the supercritical carbon dioxide exists. Then, in a state where this state is maintained, that is, in the supercritical carbon dioxide, the oil is reacted to perform the surface treatment of the silica particles.

  Here, in the surface treatment process, the oil reaction may be performed in supercritical carbon dioxide (that is, in an atmosphere of supercritical carbon dioxide), and the supercritical carbon dioxide is circulated (that is, supercritical into the closed reactor). The surface treatment may be performed while introducing or discharging carbon dioxide, or the surface treatment may be performed in a non-circulating manner.

In addition, when manufacturing silica particles by the sol-gel method, supercritical carbon dioxide may be circulated to remove the solvent from the silica particle dispersion. In this case, the surface treatment step may be performed continuously with the solvent removal step of the silica particle dispersion. That is, in the surface treatment step, for example, the surface of the silica particles may be surface-treated with oil in supercritical carbon dioxide without being released into the atmosphere before shifting from the solvent removal step.
Specifically, when the surface treatment step is performed continuously with the solvent removal step of the silica particle dispersion, in the surface treatment step, for example, supercritical carbon dioxide is introduced into and discharged from the closed reactor in the solvent removal step. Then, the temperature and pressure in the closed reactor are adjusted, and oil is added to the silica particles in a state where supercritical carbon dioxide is present in the closed reactor. And in the state which maintained this state, ie, supercritical carbon dioxide, the surface treatment of silica particles is performed with oil.

In the surface treatment step, the amount of silica particles relative to the reactor volume (that is, the charged amount) is, for example, preferably 30 g / L or more and 600 g / L or less, preferably 50 g / L or more and 500 g / L or less, more preferably 80 g / L. L to 400 g / L.
When this amount is 30 g / L or more, the concentration of oil in supercritical carbon dioxide increases, the probability of contact with the surface of the silica particles increases, and the reaction easily proceeds. On the other hand, if this amount is 600 g / L or less, the concentration of oil with respect to supercritical carbon dioxide becomes excessively high, so that the oil cannot be completely dissolved in supercritical carbon dioxide, resulting in poor dispersion and coarse aggregates. It becomes easy to suppress generation | occurrence | production.

The density of supercritical carbon dioxide is, for example, 0.10 g / ml or more and 0.80 g / ml or less, preferably 0.10 g / ml or more and 0.60 g / ml or less, more preferably 0.2 g / ml or more and 0 or less. .50 g / ml or less).
When this density is 0.10 g / ml or more, the solubility of oil in supercritical carbon dioxide increases, and the generation of coarse aggregates is easily suppressed. On the other hand, when the density is 0.80 g / ml or less, a decrease in diffusion of silica particles into the pores is suppressed, and sufficient surface treatment is easily realized. In particular, the sol-gel silica particles containing a large amount of silanol groups are preferably subjected to surface treatment in the above density range.
The density of supercritical carbon dioxide is adjusted by temperature, pressure, and the like.

  The oil includes one or more compounds selected from the group consisting of lubricating oils and fats. Specific examples of the oil include silicone oil, paraffin oil, fluorine oil, and vegetable oil. Oil may be used by 1 type and may be used multiple types.

The viscosity of the oil is, for example, 1 cSt or more and 1000 cSt or less, preferably 10 cSt or more and 500 cSt or less, more preferably 50 cSt or more and 300 cSt.
When the viscosity of the oil is 1 cSt or more, the reactivity of the oil increases and the processability to the surface of the silica particles increases, making it easy to realize sufficient oil treatment. On the other hand, when the viscosity of the oil is set to 1000 cSt or less, poor dispersion due to excessive increase in the reactivity and viscosity of the oil is suppressed, and generation of coarse aggregates is easily suppressed.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, and amino-modified. Examples include silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, and α-methylstyrene-modified silicone oil. Examples of paraffin oil include liquid paraffin. Examples of the fluorine oil include fluorine oil and fluorine chloride oil. Examples of the mineral oil include machine oil. Examples of vegetable oils include rapeseed oil and palm oil.

  Among these oils, when silicone oil is applied, the surface of the oil is uniformly applied to the silica particles in a thin film shape, and the improvement in the fluidity of the object to be attached is likely to increase.

  The amount of oil used is not particularly limited. For example, the amount is preferably 1% by mass or more and 30% by mass or less, preferably 3% by mass or more and 20% by mass or less, more preferably 5% by mass or more, with respect to the silica particles. It is 15 mass% or less.

  In addition, although oil may be used independently, you may use it as a liquid mixture with the solvent in which oil is easy to melt | dissolve. Examples of the solvent include toluene and methyl ethyl ketone.

  Here, in the surface treatment step, the silica particles may be subjected to a surface treatment with a mixture containing an oil and a silane hydrophobizing agent. By performing the surface treatment with a mixture containing oil and a silane-based hydrophobizing agent, it is possible to more effectively suppress the generation of coarse powder and realize the surface treatment in a nearly uniform state with the oil.

  The reason for this is not clear, but since the oil and the silane hydrophobizing agent are compatible with each other, they diffuse together in supercritical carbon dioxide, and when the silane hydrophobizing agent reacts on the surface of the silica particles, This is because the compatible oil is considered to adhere to the surface of the silica particles. Further, due to the property of supercritical carbon dioxide, such as “carbon dioxide in a state of temperature and pressure above the critical point and having both gas diffusibility and liquid solubility”, the temperature is relatively low (for example, 250 The reaction of the silane hydrophobizing agent proceeds at a temperature below (° C.), and free oil is likely to exist (that is, the oil diffuses in supercritical carbon dioxide and the oil is dispersed between the silica particles. This is because it is considered that the silica particles hardly aggregate during the surface treatment.

  In addition, the manufacturing method of a silica particle is 1) The method of preparing the mixture of oil and a silane type hydrophobization processing agent beforehand, throwing this mixture in the system containing a silica particle, and performing the surface treatment by the said mixture 2) Any of the methods in which the silane hydrophobizing agent and the oil are put in this order into a system containing silica particles and the surface treatment is performed with a mixture of the oil and the silane hydrophobizing agent. Good.

Examples of the silane hydrophobizing agent include known silicon compounds having an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc.), and specific examples include, for example, a silazane compound (for example, a methyl group). Silane compounds such as trimethoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, trimethylmethoxysilane, hexamethyldisilazane, tetramethyldisilazane, etc.). The silane hydrophobizing agent may be used alone or in combination.
Among these silane-based hydrophobizing agents, silicon compounds having a trimethyl group such as trimethylmethoxysilane and hexamethyldisilazane (HMDS), particularly hexamethylzine lazane (HMDS) are preferable.

The amount of the silane hydrophobizing agent used is not particularly limited. For example, the amount is preferably 1% by mass or more and 100% by mass or less, and more preferably 3% by mass or more and 80% by mass or less, more preferably with respect to the silica particles. Is 5 mass% or more and 50 mass% or less.
The ratio of the silane hydrophobizing agent and oil is, for example, 10/1 to 1/1, preferably 7/1 to 7/5, more preferably in terms of mass ratio (silane hydrophobizing agent / oil). Is 7/2 to 7/4 or less.

  The silane hydrophobizing agent may be used alone, but may be used as a mixed solution with a solvent in which the silane hydrophobizing agent is easily dissolved. Examples of the solvent include toluene and methyl ethyl ketone.

The temperature condition of the surface treatment, that is, the temperature of supercritical carbon dioxide is, for example, 80 ° C. or higher and 300 ° C. or lower, preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 120 ° C. or higher and 200 ° C. or lower.
When this temperature is 80 ° C. or higher, a decrease in surface treatment capability due to oil is easily suppressed. On the other hand, when the temperature is 300 ° C. or lower, the condensation reaction between the silanol groups of the silica particles is prevented from proceeding excessively, and the occurrence of particle aggregation is suppressed. In particular, surface treatment in the above temperature range is preferably performed on sol-gel silica particles containing a large amount of silanol groups.

  On the other hand, the pressure condition of the surface treatment, that is, the pressure of supercritical carbon dioxide may be a condition that satisfies the above-mentioned density. For example, the pressure is preferably 8 MPa to 30 MPa, preferably 10 MPa to 25 MPa, more preferably 15 MPa to 20 MPa. It is as follows.

  Through the steps described above, silica particles surface-treated with oil are obtained.

As an external additive, you may apply other external additives other than the said silica particle.
Other external additives include, for example, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide Inorganic particles such as cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Examples of other external additives include resin particles such as fluororesin and silicone resin, and particles of metal salts of higher fatty acids represented by zinc stearate.

  In addition, the surface of the inorganic particle as another external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.

(Toner production method)
Next, a toner manufacturing method according to this embodiment will be described.
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner particles after the toner particles are manufactured.

The toner particles may be produced by any of a dry production method (for example, a kneading and pulverizing method) and a wet production method (for example, an aggregation coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). The production method of the toner particles is not particularly limited, and a known production method is adopted.
Among these, it is preferable to obtain toner particles by an aggregation and coalescence method.

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing may be performed, for example, with a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

<Electrostatic image developer>
The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment.
The electrostatic image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer mixed with the toner and a carrier.

There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. As a carrier, for example, a coated carrier in which the surface of a core made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; a porous magnetic powder is impregnated with a resin Resin impregnated type carriers; and the like.
Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

  Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

  Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer. Examples thereof include a polymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.
Note that the coating resin and the matrix resin may contain other additives such as a conductive material.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating layer forming solution obtained by dissolving the coating resin and, if necessary, various additives in an appropriate solvent may be mentioned. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include a dipping method in which the core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the core material, and a state in which the core material is suspended by flowing air. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed, a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

<Image Forming Apparatus / Image Forming Method>
The image forming apparatus / image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium A transfer unit that transfers the toner image transferred onto the surface of the recording medium, and a fixing unit that fixes the toner image transferred onto the surface of the recording medium. The electrostatic charge image developer according to this embodiment is applied as the electrostatic charge image developer.

  In the image forming apparatus according to this embodiment, a charging process for charging the surface of the image carrier, an electrostatic charge image forming process for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic charge according to this embodiment. A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium; An image forming method (an image forming method according to this embodiment) including a cleaning process for cleaning the surface of the image carrier with a cleaning blade and a fixing process for fixing the toner image transferred to the surface of the recording medium is performed. The

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member Intermediate transfer system device that primarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the intermediate transfer body; then neutralizes the image on the surface of the image carrier after the toner image is transferred and before charging. A well-known image forming apparatus such as an apparatus provided with a neutralizing unit that performs neutralization by irradiating is applied.
In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body. And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including a developing unit containing the electrostatic charge image developer according to the present embodiment is preferably used.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other in the left to right direction in the drawing. The vehicle travels in the direction toward the unit 10K. The support roll 24 is applied with a force in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the drive roll 22.
Further, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K has yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The toner including the four color toners is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first unit 10Y instead of yellow (Y). Description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y includes a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on a color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A photoreceptor cleaning device having a primary transfer roll 5Y (an example of a primary transfer unit) that transfers a toner image onto the intermediate transfer belt 20, and a cleaning blade 6Y-1 that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. (Example of cleaning means) 6Y are arranged in order.
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (for example, volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (general resin resistance), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image having a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is visualized (developed image) as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged electric charge on the photoreceptor 1Y, and has a developer roll (a developer holding member). Example) is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y is applied to the toner image, so that the photoreceptor is exposed. The toner image on 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the polarity (−) of the toner, and is controlled to +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning blade 6Y-1 of the photoreceptor cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 on which the four color toner images are transferred in multiple ways through the first to fourth units is disposed on the image transfer surface side of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roll (an example of a secondary transfer unit) 26 is formed to a secondary transfer portion configured. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

  Thereafter, the recording paper P is fed into the pressure contact portions (nip portions) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image.

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. In addition to the recording paper P, the recording medium may be an OHP sheet.
In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is also preferably smooth. For example, coated paper with the surface of plain paper coated with resin, art paper for printing, etc. are preferably used. Is done.

  The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge / toner cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment accommodates the electrostatic image developer according to the present embodiment, and develops the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer. And a process cartridge that can be attached to and detached from the image forming apparatus.

  Note that the process cartridge according to the present embodiment is not limited to the above-described configuration, and other means such as a developing device and other units such as an image carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one selected from the above.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 and the photoconductor 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. A charged roll 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), and a photosensitive member cleaning device 113 (an example of a cleaning unit) having a cleaning blade 113-1 are held in an integrated combination. It is configured and made into a cartridge.
In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (a recording medium). An example).

Next, the toner cartridge according to this embodiment will be described.
The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are each developing devices (colors). And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to these Examples at all. Further, “part” means “part by mass” unless otherwise specified.

[Preparation of silica particles]
(Preparation of silica particles (S1))
As shown below, the silica particles were surface-treated with oil. In addition, the apparatus equipped with the carbon dioxide cylinder, the carbon dioxide pump, the entrainer pump, the autoclave with a stirrer (capacity 500 ml), and the pressure valve was used for the surface treatment.

First, 300 parts of a sol-gel silica particle dispersion having a volume average particle size of 120 nm and a solid content concentration of 40% by mass were charged into an autoclave equipped with a stirrer (capacity: 500 ml). Thereafter, liquefied carbon dioxide was injected into the autoclave, and the temperature was raised by a carbon dioxide pump while the temperature was raised by a heater, and the inside of the autoclave was brought to a supercritical state of 150 ° C. and 15 MPa. And in the state which maintained the supercritical state of the carbon dioxide in the autoclave, 16 parts of dimethyl silicone oil (DSO: brand name "KF-96 (made by Shin-Etsu Chemical Co., Ltd.))" and silane type hydrophobizing agent as oil As a mixture, 35 parts of hexamethylzine lazan (HMDS: manufactured by Organic Synthetic Chemical Industry Co., Ltd.) was added to the autoclave with an entrainer pump, and the mixture was held for 30 minutes while stirring with a stirrer. Then, stirring was stopped, the pressure valve was opened, the pressure in the autoclave was released to atmospheric pressure, and the temperature was lowered to room temperature (25 ° C.).
In this way, surface treatment with oil was performed to obtain silica particles (S1).

(Preparation of silica particles (S2) to (S4))
In the production of silica particles (S1), the type of silica particles to be treated and the surface treatment conditions (atmosphere, oil type and number of parts, silane hydrophobizing agent and number of parts, and treatment time) were changed according to Table 1. Except that, silica particles (S2) to (S4) were produced in the same manner as silica particles (S1).
However, the silica particles (S4) were replaced with a mixture of oil and silane hydrophobizing agent, and a mixture of oil and solvent (composition described in Table 1) was used to produce silica particles (S4). .
The silica particles (S9) are commercially available fumed silica ("OX50 (manufactured by Nippon Aerosil Co., Ltd.)") obtained by a vapor phase method, and the silica powder is subjected to a surface treatment to obtain silica particles. (S9) was produced.

(Production of comparative silica particles (SC1) to (SC4))
In the production of silica particles (S1), the type of silica particles to be treated, the surface treatment conditions (atmosphere, oil type and number of parts, silane-based hydrophobizing agent) according to Table 1, not in supercritical carbon dioxide but in the air atmosphere Silica particles (SC1) to (SC4) were produced in the same manner as the silica particles (S1) except that the number of parts and the treatment time were changed.
However, as comparative silica particles (SC3), instead of a mixture of oil and silane hydrophobizing agent, a mixture of oil and solvent (composition described in Table 1) is used to produce silica particles (SC3). did.
The comparative silica particle (SC4) is a commercially available fumed silica ("OX50 (manufactured by Nippon Aerosil Co., Ltd.)") obtained by a gas phase method, and the silica powder is subjected to a surface treatment to obtain silica. Particles (S4) were produced.

[Synthesis of amorphous polyester resin]
(Synthesis of amorphous polyester resin 1)
-Bisphenol A ethylene oxide 2.2 mol adduct: 40 mol parts-Bisphenol A propylene oxide 2.2 mol adduct: 60 mol parts-Terephthalic acid: 47 mol parts-Fumaric acid: 40 mol parts-Dodecenyl succinic anhydride: 15 mol parts / trimellitic anhydride: 3 mol parts In a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas introduction tube, among the above monomer components other than fumaric acid and trimellitic anhydride, dioctanoic acid Tin was added in an amount of 0.25 parts with respect to a total of 100 parts of the monomer components. After reacting at 235 ° C. for 6 hours under a nitrogen gas stream, the temperature was lowered to 200 ° C., and the fumaric acid and trimellitic anhydride were added and reacted for 1 hour. The temperature was further raised to 220 ° C. over 4 hours, and polymerization was carried out under a pressure of 10 kPa until the desired molecular weight was obtained. Thus, a pale yellow transparent amorphous polyester resin 1 was obtained.
The obtained amorphous polyester resin 1 has a glass transition temperature Tg by DSC of 59 ° C., a mass average molecular weight Mw by GPC of 25,000, a number average molecular weight Mn of 7,000, and a softening temperature by a flow tester of 107 ° C. The acid value AV was 13 mgKOH / g.

[Preparation of Amorphous Polyester Resin Particle Dispersion]
(Preparation of amorphous polyester resin particle dispersion 1)
While maintaining a jacketed 3 liter reaction tank (manufactured by Tokyo Rika Kikai Co., Ltd .: BJ-30N) equipped with a condenser, a thermometer, a water dropping device, and an anchor wing at 40 ° C. in a water circulation thermostat, the reaction tank Into this, a mixed solvent of 160 parts of ethyl acetate and 100 parts of isopropyl alcohol was added, and 300 parts of the amorphous polyester resin 1 was added thereto, and stirred at 150 rpm using a three-one motor to dissolve the oil phase. Obtained. To this stirred oil phase, 14 parts of a 10% aqueous ammonia solution was added dropwise for 5 minutes, mixed for 10 minutes, and 900 parts of ion-exchanged water was further added dropwise at a rate of 7 parts per minute to cause phase inversion. Thus, an emulsion was obtained.
Immediately, 800 parts of the obtained emulsion and 700 parts of ion-exchanged water were put into a 2-liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. While rotating the eggplant flask, the mixture was heated in a hot water bath at 60 ° C., and the solvent was removed by reducing the pressure to 7 kPa while paying attention to bumping. When the solvent recovery amount reached 1,100 parts, the pressure was returned to normal pressure, and the eggplant flask was cooled with water to obtain a dispersion. There was no solvent odor in the obtained dispersion. The volume average particle diameter D50 of the resin particles in this dispersion was 130 nm. Then, ion-exchange water was added and it prepared so that solid content concentration might be 20%, and this was made into the amorphous polyester resin particle dispersion 1.

[Synthesis of crystalline polyester resin]
(Synthesis of crystalline polyester resin 1)
-1,10-dodecanedioic acid: 50 mol parts-1,9-nonanediol: 50 mol parts The above monomer components are placed in a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas introduction tube. Was replaced with dry nitrogen gas, and 0.25 parts of titanium tetrabutoxide (reagent) was added to 100 parts of the monomer component. After stirring and reacting at 170 ° C. for 3 hours under a nitrogen gas stream, the temperature was further raised to 210 ° C. over 1 hour, the pressure inside the reaction vessel was reduced to 3 kPa, and the stirring reaction was performed for 13 hours under reduced pressure to produce crystals. -Soluble polyester resin 1 was obtained.
The obtained crystalline polyester resin 1 has a melting temperature by DSC of 73.6 ° C., a mass average molecular weight Mw by GPC of 25,000, a number average molecular weight Mn of 10,500, and an acid value AV of 10.1 mgKOH / g. there were.

[Preparation of Amorphous Polyester Resin Particle Dispersion]
(Preparation of crystalline polyester resin particle dispersion 1)
A jacketed 3 liter reactor (Tokyo Rika Kikai Co., Ltd .: BJ-30N) equipped with a condenser, thermometer, water dripping device, anchor blade, 300 parts of the crystalline polyester resin and 160 parts of methyl ethyl ketone (solvent) And 100 parts of isopropyl alcohol (solvent) were added, and the resin was dissolved while stirring and mixing at 100 rpm while maintaining the temperature at 70 ° C. in a water circulating thermostat (dissolution preparation step).
Thereafter, the stirring speed was set to 150 rpm, the water circulating thermostat was set to 66 ° C., 17 parts of 10% ammonia water (reagent) was added over 10 minutes, and then 7 parts / ion of ion-exchanged water kept at 66 ° C. A total of 900 parts was dropped at a rate of minutes to invert the phase to obtain an emulsion.
Immediately, 800 parts of the obtained emulsion and 700 parts of ion-exchanged water were put into a 2-liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. While rotating the eggplant flask, the mixture was heated in a hot water bath at 60 ° C., and the solvent was removed by reducing the pressure to 7 kPa while paying attention to bumping. When the solvent recovery amount reached 1,100 parts, the pressure was returned to normal pressure, and the eggplant flask was cooled with water to obtain a dispersion. There was no solvent odor in the obtained dispersion. The volume average particle diameter D50v of the resin particles in this dispersion was 130 nm. Thereafter, ion exchange water was added to prepare a solid content concentration of 20%, and this was used as a crystalline polyester resin particle dispersion.

[Preparation of colorant particle dispersion]
(Preparation of black pigment particle dispersion 1)
Carbon black (Cabot, Regal 330): 250 parts Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen SC): 33 parts (60% active ingredient, 8% based on colorant)
・ Ion-exchanged water: 750 parts Ion-exchanged water and 280 parts of ion-exchanged water in a stainless steel container whose liquid level is about 1/3 of the height of the container when all of the above components are added. After 33 parts of the agent was added and the surfactant was sufficiently dissolved, all of the solid solution pigment was added, and the mixture was stirred using a stirrer until there was no wet pigment, and was sufficiently degassed. After defoaming, the remaining ion-exchanged water was added, and the mixture was dispersed for 10 minutes at 5000 revolutions using a homogenizer (manufactured by IKA, Ultra Tarrax T50). After defoaming, the mixture was dispersed again at 6000 rpm for 10 minutes using a homogenizer, and then defoamed by stirring for one day with a stirrer. Subsequently, the dispersion liquid was dispersed at a pressure of 240 MPa using a high-pressure impact disperser ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). The dispersion was equivalent to 25 passes in terms of the total charge and the processing capacity of the apparatus. The obtained dispersion was allowed to stand for 72 hours to remove precipitates, and ion exchange water was added to adjust the solid content concentration to 15%, whereby black pigment particle dispersion 1 was obtained. The volume average particle diameter D50 of the particles in this black pigment particle dispersion 1 was 135 nm.

[Preparation of release agent particle dispersion]
(Preparation of release agent particle dispersion 1)
・ Hydrocarbon wax (Nippon Seiki Co., Ltd., trade name: FNP0080, melting temperature = 80 ° C.): 270 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK, active ingredient amount) : 60%): 13.5 parts (as active ingredient, 3.0% with respect to the release agent)
-Ion-exchanged water: 21.6 parts The above components were mixed, and the release agent was dissolved at a temperature of the internal solution of 120 ° C with a pressure discharge type homogenizer (Gorin homogenizer manufactured by Gorin), and then at a dispersion pressure of 5 MPa for 120 minutes. Subsequently, a dispersion treatment was performed at 40 MPa for 360 minutes, followed by cooling to obtain a release agent particle dispersion 1. The volume average particle diameter D50 of the particles in this release agent dispersion is 225 nm. Thereafter, ion exchange water was added to adjust the solid content concentration to 20.0%.

[Preparation of aqueous aluminum sulfate solution]
Aluminum sulfate powder (Asada Chemical Industry Co., Ltd .: 17% aluminum sulfate): 35 parts Ion exchange water: 1,965 parts The above components are put into a 2 liter container, and the precipitate disappears at 30 ° C. The mixture was stirred and mixed to prepare an aqueous aluminum sulfate solution.

[Example 1]
(Production of toner particles)
Amorphous polyester resin particle dispersion 1: 700 parts Crystalline polyester resin particle dispersion 1: 50 parts Black pigment particle dispersion 1: 133 parts Release agent particle dispersion 1: 100 parts Ion exchange water : 350 parts · Anionic surfactant (Dowfax2A1 manufactured by Dow Chemical Co., Ltd.): 2.9 parts The above ingredients were placed in a 3 liter reaction vessel equipped with a thermometer, pH meter, and stirrer at a temperature of 25 ° C. Then, 1.0% nitric acid was added to adjust the pH to 3.0, and then 130 parts of the prepared aqueous aluminum sulfate solution was dispersed while being dispersed at 5,000 rpm with a homogenizer (IKA Japan Co., Ltd .: Ultra Tarax T50). Added and dispersed for 6 minutes.
Thereafter, a stirrer and a mantle heater are installed in the reaction vessel, and the temperature increase rate is 0.2 ° C./min up to a temperature of 40 ° C. while adjusting the rotation speed of the stirrer so that the slurry is sufficiently stirred. After exceeding the temperature, the temperature was increased at a temperature increase rate of 0.05 ° C./min, and the particle size was measured every 10 minutes with Multisizer II (aperture diameter: 50 μm, manufactured by Coulter). The temperature was maintained when the volume average particle diameter reached 5.0 μm, and 1:50 parts of the amorphous polyester resin dispersion was added over 5 minutes.
After maintaining for 30 minutes, the pH was adjusted to 9.0 with 1% aqueous sodium hydroxide solution. Thereafter, the temperature was raised to 90 ° C. at a rate of temperature rise of 1 ° C./min while maintaining the temperature at 98 ° C. while adjusting the pH to 9.0 at every 5 ° C. in the same manner. When the particle shape and surface properties were observed with an optical microscope and a scanning electron microscope (FE-SEM), coalescence of the particles was confirmed at 10.0 hours, and the container was cooled to 30 ° C. for 5 minutes with cooling water. And cooled.
The cooled toner slurry was passed through a nylon mesh having a mesh size of 15 μm to remove coarse powder, and the toner slurry passed through the mesh was filtered under reduced pressure with an aspirator. The toner slurry remaining on the filter paper was crushed as finely as possible by hand, poured into ion-exchanged water 10 times the amount of toner at a temperature of 30 ° C., and stirred and mixed for 30 minutes. Subsequently, it is filtered under reduced pressure with an aspirator, and the toner slurry remaining on the filter paper is crushed as finely as possible by hand, and is poured into ion-exchanged water of 10 times the amount of toner at a temperature of 30 ° C., stirred and mixed for 30 minutes, and again with an aspirator The filtrate was filtered under reduced pressure, and the electrical conductivity of the filtrate was measured. This operation was repeated until the electric conductivity of the filtrate reached 10 μS / cm or less, and the toner slurry was washed.
The washed toner slurry was finely pulverized with a wet dry granulator (Comil) and then vacuum dried in an oven at 35 ° C. for 36 hours to obtain toner particles.
The obtained toner particles had a volume average particle diameter D50 of 6.0 μm and a shape factor of 0.960 (manufactured by Sysmex Corporation, FPIA-3000). When the SEM image of the toner was observed, it had a smooth surface and no defects such as protrusion of the release agent and peeling of the surface layer were observed.

(Production of toner)
To 60 parts of the obtained toner particles, 2 parts of silica particles (S1) were added as an external additive, and mixed at 13,000 rpm for 30 seconds using a sample mill. Thereafter, the toner was obtained by sieving with a vibrating sieve having an opening of 45 μm.

(Development of developer)
8 parts of toner and 92 parts of carrier were stirred for 20 minutes at 40 rpm using a V-blender, and sieved with a sieve having an opening of 250 μm to prepare a developer. However, the following carrier 1 was used as a carrier.

-Production of carrier 1-
Ferrite particles (average particle size: 50 μm): 100 parts Toluene: 14 parts Styrene-methyl methacrylate copolymer (component ratio: 90/10): 2 parts Carbon black (R330: manufactured by Cabot Corporation): 0. Part 2 First, the above components other than the ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution. Next, the coating solution and ferrite particles are placed in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes. After that, the carrier 1 was produced by further depressurizing while heating and degassing and drying.

[Examples 2-9, Comparative Examples 1-2]
Each toner was prepared in the same manner as in Example 1 except that the silica particle type as the external additive was changed according to Table 2. A developer was prepared using each toner in the same manner as in Example 1.

[Evaluation]
The toner and developer obtained in each example were evaluated as follows. The results are shown in Table 2.

(Free oil amount and its standard deviation)
The amount of free oil in the silica particles of the toner obtained in each example and its standard deviation were measured according to the method described above.

(Actual machine evaluation)
The developer obtained in each example was filled in a developing device of an image forming apparatus “Color 1000 press (equipment equipped with a cleaning blade for cleaning a photosensitive member)” manufactured by Fuji Xerox Co., Ltd. The following evaluation was performed using this image forming apparatus.

-Torque-up evaluation of photoconductors-
In a high-temperature and high-humidity environment (28 ° C., 85% RH), a halftone image having an image density of 4% is printed on an A3 paper (J paper manufactured by Fuji Xerox Co., Ltd.) with an image forming apparatus at a process speed of 350 mm / sec. Continued to output. At that time, a torque meter was attached to the apparatus, and the rotational torque of the photosensitive member was monitored to examine the rotational torque (Ncm) of the photosensitive member when 25,000 sheets were output. This evaluated the torque increase of the photoreceptor. However, when the motor stopped due to an increase in the rotational torque of the photosensitive member and an error display was displayed from the apparatus, the evaluation was terminated there.
The evaluation criteria are as follows, and up to C (Δ) is a good range.
A (◎): 0 Ncm ≦ rotational torque <80 Ncm
B (◯): 80 Ncm ≦ rotational torque <100 Ncm
C (Δ): 100 Ncm ≦ rotational torque <130 Ncm
D (×): 130 Ncm ≦ rotational torque <150 Ncm, or there is an error display

-Toner fluidity evaluation-
In a high-temperature and high-humidity environment (28 ° C., 85% RH), when the rotation speed of the conveying member (auger) of the cartridge unit is set to 100 rpm, a weighing machine is attached to the apparatus at that time, The conveyance speed (mg / s) was examined. Thus, the fluidity of the toner was evaluated. The evaluation criteria are as follows, and C (Δ) is a good range.
A (◎): 550 mg / s <Developer transport speed B (◯): 400 mg / s ≦ Developer transport speed <550 mg / s
C (Δ): 300 Ncm ≦ conveyance speed of developer <400 mg / s
D (x): developer transport speed <300 mg / s

From the above results, it can be seen that in this embodiment, a better result is obtained for the evaluation of the torque increase of the photoconductor than in the comparative example.
In Example 1 in which the volume average particle diameter of the silica particles is more than 50 nm, a better result is obtained with respect to the evaluation of the torque increase of the photoconductor than in Example 6 in which the volume average particle diameter of the silica particles is less than 50 nm. I understand that.
Example 1 in which the volume average particle diameter of the silica particles is less than 200 nm has a better result of evaluating the fluidity of the toner than Example 8 in which the volume average particle diameter of the silica particles is 200 nm or more. I understand that.
Example 1 in which the silica particles are surface-treated with a mixture containing a silane coupling agent together with oil, compared with Example 5 where the silica particles are surface-treated with a mixture containing oil and toluene, the torque of the photoreceptor is increased. It can be seen that good results have been obtained for the evaluation.
In Examples 1 to 4, it can be seen that, compared with Examples 5 to 6 and 8 to 9, good results are obtained in terms of torque increase of the photosensitive member and fluidity of the toner.

1Y, 1M, 1C, 1K photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
30 Intermediate transfer member cleaning device 107 Photosensitive member (an example of an image holding member)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Attachment rail 118 Opening 117 for exposure 117 Case 200 Process cartridge 300 Recording paper (an example of recording medium)
P Recording paper (an example of a recording medium)

Claims (9)

Toner particles,
Silica particles adhering to the surface of the toner particles, the surface of which is treated with oil, and the standard deviation σ of the amount of free oil is 0.5 or less,
A toner for developing an electrostatic charge image.   The toner for developing an electrostatic image according to claim 1, wherein the silica particles are silica particles having a volume average particle diameter of more than 50 nm and less than 200 nm.   The electrostatic image developing toner according to claim 1, wherein the silica particles are silica particles that are surface-treated with oil in supercritical carbon dioxide.   The electrostatic image developing toner according to claim 3, wherein the silica particles are silica particles surface-treated with a mixture containing a silane hydrophobizing agent together with the oil.   An electrostatic charge image developer containing the electrostatic charge image developing toner according to claim 1. Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 4,
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for containing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A cleaning step of cleaning the surface of the image carrier with a cleaning blade;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: