JP7070097B2 - Electrophotographic toner, toner storage unit, and image forming apparatus - Google Patents

Description

The present invention relates to an electrophotographic toner.

In recent years, in the formation of images such as electrographs, there is an increasing demand for higher image quality, and toners are being made smaller and spherical.
By reducing the particle size of the toner, the reproducibility of one section (dot) of the formed image is improved, and by making the toner spherical, the developability and transferability are improved.

However, due to the effect of the toner having a smaller particle size, for example, the toners tend to be tightly clogged with each other, resulting in deterioration of cohesiveness, and the toner easily slips between the member to be cleaned such as a photoconductor and the blade. There has been a problem that filming is likely to occur due to poor cleaning and adhesion to the surface of the photoconductor.
As one of the means for solving these problems, an external additive has been used for the toner to reduce the release rate of the external additive. For example, a method has been proposed in which the release rate of silica used as an external additive is suppressed to a certain value or less to maintain stable and high-quality image quality during actual machine image formation (for example, Patent Documents 1 and 2). reference).

As a means different from the above-mentioned means, for example, a method of devising an external additive to be used has also been used. For example, a method of using silica having a specific property (satisfying a specific parameter) has been proposed (see, for example, Patent Documents 3 to 4). Further, a method of externally adding two kinds of external additives having different sizes with a single primary particle has been proposed (see, for example, Patent Document 5). Further, a method using an external additive having a large particle size has been proposed (see, for example, Patent Document 6).

An object of the present invention is to provide a toner for electrophotographic which can prevent contamination of a photoconductor and has excellent durability.

The electrophotographic toner of the present invention as a means for solving the above-mentioned problems is
An electrophotographic toner containing a toner matrix particle containing a binder resin and an external additive containing silica, wherein the external agent satisfies the following (1) to (4). And.
(1) The release rate of the silica is 40% or more and 80% or less.
(2) The liberated external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
(3) The volume average particle diameter of the particles having a diameter equivalent to a circle of 50 nm or more is 100 nm or more and 160 nm or less.
(4) The ratio (circumscribed circle area / particle area) between the circumscribed circle area and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 1.80 or more and 3.00 or less.

According to the present invention, it is possible to provide an electrophotographic toner which can prevent contamination of a photoconductor and has excellent durability.

FIG. 1 is a diagram showing an example of a circumscribed circle of an external additive in the present invention. FIG. 2 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention.

(toner)
The toner of the present invention contains a parent particle and an external additive.
The parent particles contain a binder resin and, if necessary, other components.
The external additive contains silica and satisfies the following (1) to (4).
(1) The release rate of the silica is 40% or more and 80% or less.
(2) The liberated external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
(3) The volume average particle diameter of the particles having a diameter equivalent to a circle of 50 nm or more is 100 nm or more and 160 nm or less.
(4) The ratio (circumscribed circle area / particle area) between the circumscribed circle area and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 1.80 or more and 3.00 or less.

Until now, as one of the means for preventing poor cleaning and contamination of the photoconductor, the release rate of the external additive silica has been reduced. It is known that the released external additive forms agglomerates (dams) of the external additive at the contact portion with the cleaning blade. When the amount of free silica is large and the supply to the dam portion is excessive, the friction of the silica particles is weak and the particles are easy to move, that is, when the dam is easy to collapse, photoconductor contamination occurs. This is because a part of the dam collapses over time and slips between the image carrier and the blade, creating a non-contact portion (gap), resulting in poor cleaning and the slipped silica particles sticking to the surface of the photoconductor. Because. Therefore, it is effective in preventing photoconductor contamination by reducing the release rate of silica.
However, the presence of the free silica can alleviate the contact between the toner particles and improve the storage stability. In particular, when image formation is continued in the actual machine for a long period of time, the accumulated toner particles may aggregate with each other, leading to the generation of an abnormal image. Therefore, in order to maintain good image quality for a long period of time, it is preferable that a certain amount of free silica is present.

As a result of studies by the present inventors in view of the above points, by setting the external additive under the following conditions, it is excellent in cleaning property and prevention of photoconductor contamination even though a certain amount of free silica is present. It was possible to obtain the toner, and it was possible to achieve both storage stability.
-The released external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
The volume average particle size of the particles having a diameter equivalent to a circle of 50 nm or more is 100 nm or more and 160 nm or less.
The ratio of the circumscribed circle area to the particle area (circumscribed circle area / particle area) is 1.80 or more and 3.00 or less for the particles having an equivalent circle diameter of 50 nm or more.

<External agent>
The external additive contains silica and, if necessary, other components.
The silica is preferably fumed silica because it is easy to produce silica particles having high deformability.

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include inorganic particles.
Examples of the inorganic particles include alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, fluorine compound, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, and mica. , Silica ash, silica soil, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like. These may be used alone or in combination of two or more. When two or more types are used in combination, it is preferable to select them so as to have resistance to development stress such as idling.
Among these, titanium oxide, strontium titanate, and alumina are preferable.

<< Silica release rate >>
The release rate of silica in the present invention is a value obtained when the toner is treated by the following procedure (free treatment).
(1) Preparation of surfactant solution Add 5.00 g of surfactant and 300 mL of distilled water to a 500 mL beaker and dissolve them. Then, the volumetric flask is increased to 1,000 mL to obtain a surfactant solution.
Drywell (manufactured by Fuji Film Co., Ltd.) is used as the surfactant.
(2) Preparation of toner dispersion solution Weigh 3.75 g of toner, add 50 mL of the surfactant solution, and uniformly disperse the toner in the surfactant solution.
(3) Applying ultrasonic energy Ultrasonic energy is applied to the toner dispersion at 40 W for 1 minute.
(4) Separation of free external additive, (5) Filtration, (6) Drying The ultrasonically applied toner dispersion solution is centrifuged at 2,000 rpm for 2 minutes, filtered, and the obtained toner is dried.
(7) Measurement of X-rays The amount of silica contained in the toner after the liberation treatment obtained in the above (1) to (6) and the toner before the liberation treatment is quantified by the fluorescent X-ray method, and the following formula is used. The value obtained by substitution is used as the silica release rate.
(Silica release rate) = (Amount of silica contained in toner before release treatment-Amount of silica contained in toner after release treatment) / (Amount of silica contained in toner before release treatment) x 100

The release rate of the silica is 40% or more and 80% or less, preferably 40% or more and 60% or less. If the release rate of silica is less than 40%, the effect of relaxing the contact between the toner particles is weak, and the storage stability when forming an image in an actual machine for a long period of time may be impaired. In particular, it is likely to be affected in a high temperature and high humidity environment, and streaky or speckled abnormalities may be observed on the image. Further, when the release rate of silica exceeds 80%, the amount of silica present in the cleaning blade becomes excessive, and even if the external additive having the shape in the present invention is used, cleaning failure and photoconductor contamination can be suppressed. There are things you can't do.

In the toner of the present invention, the liberated external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
The released external additive is an external additive contained in the supernatant liquid separated after centrifugation ((4) in the above silica release rate measurement operation) in the above-mentioned external agent release rate measurement operation. Point to.
The maximum value of the equivalent circle diameter of the free external additive is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 250 nm or less.

As for the shape of the particles having a diameter equivalent to a circle of 50 nm or more, it is preferable that the particles have irregular shapes rather than true spheres. Specifically, the particles having a diameter equivalent to a circle of 50 nm or more are preferably aggregate particles (secondary particles) formed by aggregates. When it is formed of agglomerated particles, it is possible to prevent a problem that the shape deformability is limited. When particles other than aggregated particles are used, it is necessary to increase the particle size of the external additive in order to increase the ratio of the circumscribed circle area to the particle area as in the present invention.

The ratio of the particle area of the particles having a diameter equivalent to a circle of 50 nm or more is not particularly limited and may be appropriately selected depending on the intended purpose, but is 30% or more with respect to the total particle area of the released external additive. Is preferable, and 50% or more is more preferable. When the ratio is 30% or more, it is possible to more highly prevent the problem that the photoconductor contamination is aggravated. The upper limit of the ratio is preferably 85% or less.

The volume average particle diameter of the particles having a circle-equivalent diameter of 50 nm or more is 100 nm or more and 160 nm or less, preferably 110 nm or more and 150 nm or less. When the volume average particle size is less than 100 nm, it is easy to slip through the cleaning blade and worsen the photoconductor contamination. Further, when the volume average particle size exceeds 160 nm, the surface of the photoconductor tends to be damaged, and the image is likely to be deteriorated when used for a long period of time.

The ratio (circumscribed circle area / particle area) between the circumscribed circle area of the particles having a circle equivalent diameter of 50 nm or more and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 1.80 or more and 3.00 or less. It is preferably 2.00 or more and 2.80 or less. If the ratio (area ratio) is less than 1.80, the shape approaches a spherical shape, which may deteriorate the cleaning property. If the ratio (area ratio) exceeds 3.00, the charging characteristics and the like over time may not be stable, and the function as a toner may not be satisfied.

The ratio (area ratio) is a parameter indicating the deformability of the external additive. Generally, when showing irregularity, the average circularity calculated from the ratio of the particle area to the square of the perimeter is used. However, since the average circularity is not sufficient to show the irregularity of the shape, in the present invention, the degree of irregularity is expressed by the ratio of the circumscribed circle area to the particle area.
FIG. 1 shows the circumscribed circle of the circumscribed circle.

<< Measurement of circle-equivalent diameter, volume average particle size, and area ratio of free external additive >>
The volume average particle size and area ratio (circumferential circle area / particle area) of the released external additive are determined after centrifugation ((4) in the above silica release rate measurement work) in the external additive release rate measurement work. It can be measured by the following method using the separated supernatant.
The supernatant is observed with a transmission electron microscope to obtain an image. The obtained image is binarized by the image processing software A image (Asahi Kasei Engineering Co., Ltd.), and the equivalent circle diameter, particle area, and circumscribed circle area are calculated.
The above calculation is performed using the "circle equivalent diameter 2", "area", and "circumscribed circle diameter" obtained in the particle analysis mode of the image A.
The equivalent circle diameter is obtained by converting the value obtained above into the value of the diameter, assuming that the value is due to the circular area.
For the particle area, the value of "area" obtained by binarization is used as it is.
The circumscribed circle area is calculated from the "circumscribed circle diameter" obtained by binarization.
The area ratio (circumscribed circle area / particle area) is obtained by dividing the "average circumscribed circle area" obtained above by the "average particle area".
For the volume average particle size, calculate the volume from the equivalent circle diameter obtained above using the same software, and divide the sum of the product of the particle diameter and the volume by the sum of the volumes ([(particle diameter x volume) of each measured particle). / Total volume of each measured particle]).
The details of the analysis conditions for this analysis are described below.
Binarization method (threshold value): Manual setting (visual)
Range specification: Yes Outer edge correction: No Hole filling: Yes Shrinkage separation: No The reason why the binarization threshold is set manually in the above is to distinguish between the unevenness of the toner surface and the external additive. If the contrast on the same image changes drastically when binarizing, the analysis range is specified near one particle, and the threshold value is set by observing the particle in one particle and the surrounding area.
When determining the ratio of the particle area of particles with a circle equivalent diameter of 50 nm or more to the total particle area of the released external additive, [total particle area with a circle equivalent diameter of 50 nm or more / total released particles It can be calculated by [total particle area].

The content of the external additive is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.3% by mass to 5.5% by mass with respect to the entire parent particles described later.

<Mother particle>
The mother particles (also referred to as “toner mother particles”) preferably contain a binder resin, a mold release agent, and a wax dispersant, and further contain other components, if necessary.

<< Bundling resin >>
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a styrene resin (a homopolymer or copolymer containing styrene or a styrene substituent), a vinyl chloride resin, or styrene. / Vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene / ethyl acrylate copolymer, xylene resin, polyvinyl butyral Examples thereof include resins, petroleum-based resins, and hydrogenated petroleum-based resins.
Examples of the styrene resin (polypolymer or copolymer containing styrene or styrene substituent) include polystyrene, chloropolystyrene, polyα-methylstyrene, styrene / chlorostyrene copolymer, styrene / propylene copolymer, and styrene. / Butadiene copolymer, styrene / vinyl chloride copolymer, styrene / vinyl acetate copolymer, styrene / maleic acid copolymer, styrene / acrylic acid ester copolymer (styrene / methyl acrylate copolymer, styrene / Ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / phenyl acrylate copolymer, etc.), styrene / methacrylic acid ester copolymer (styrene / methyl methacrylate) Copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / phenyl methacrylate copolymer, etc.), styrene / α-methyl chloroacrylate copolymer, styrene / acrylonitrile / acrylic Examples thereof include acid ester copolymers.
These may be used alone or in combination of two or more. Among these, polyester resin is preferable from the viewpoint of low-temperature fixability and environmental safety (VOC due to residual monomer).

<<< Polyester resin >>>
As the polyester resin, any one obtained by a polycondensation reaction between a generally known alcohol and a carboxylic acid can be used.
Examples of the alcohol include diols, etherified bisphenols, a divalent alcohol monomer in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, and a high alcohol unit amount of trihydric or higher. The body etc. can be mentioned.
Examples of the diols include polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butenediol and the like. Can be mentioned.
Examples of the etherified bisphenols include 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylene bisphenol A, and polyoxypropylene bisphenol A.
Examples of the trihydric or higher alcohol monomer include sorbitol, 1,2,3,6-hexanetetrol, 1,4-salbitan, pentaesritol dipentaesritol, and tripentaesritol. , Citrus, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, Examples thereof include 1,3,5-trihydroxymethylbenzene.
These may be used alone or in combination of two or more.

Examples of the carboxylic acid include a monocarboxylic acid, a divalent organic acid monomer, an anhydride of these acids, a dimer of a lower alkyl ester and a linoleic acid, and a trivalent or higher polyvalent carboxylic acid monomer. And so on.
Examples of the monocarboxylic acid include palmitic acid, stearic acid, and oleic acid.
Examples of the divalent organic acid monomer include maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebatic acid, and malonic acid, which have 3 carbon atoms. Examples thereof include those substituted with ~ 22 saturated or unsaturated hydrocarbon groups.
Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2. , 4-Naphthalentricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane , 1,2,7,8-octanetetracarboxylic acid embol trimeric acid, anhydrides of these acids and the like.
These may be used alone or in combination of two or more.

The method for producing the binder resin is not particularly limited and may be appropriately selected. For example, bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used.

<< Other ingredients >>
The other components are not particularly limited as long as they are used for ordinary toner, and can be appropriately selected depending on the intended purpose. For example, a colorant, a mold release agent, a trivalent or higher metal salt, and the like. Examples include wax dispersants.

<<< Colorant >>>
Examples of the colorant used for the toner of the present invention include carbon black, lamp black, iron black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone, and benzidine yellow. Conventionally known dyes and pigments such as dyes and pigments such as rosebengal and triallylmethane dyes can be used. These can be used alone or in combination, and can be used as a black toner or a full-color toner.
The content of these colorants is preferably 1% by mass to 30% by mass, more preferably 3% by mass to 20% by mass, based on the binder resin component of the toner.

<<< Metal salt of trivalent or higher >>>
The toner of the present invention preferably contains a trivalent or higher metal salt. By containing the metal salt, a cross-linking reaction with the acidic group of the binder resin proceeds at the time of fixing, and a weak three-dimensional cross-linking is formed to obtain high temperature offset resistance while maintaining low temperature fixing property. Can be done.
As the metal salt, for example, at least one selected from a metal salt of a salicylic acid derivative and an acetylacetonate metal salt is preferable. The metal is not particularly limited as long as it is a trivalent or higher-valent polyvalent ion metal, and examples thereof include iron, zirconium, aluminum, titanium, and nickel.
As the trivalent or higher metal salt, a trivalent or higher salicylic acid metal compound is preferable.
The content of the metal salt is, for example, preferably 0.5 to 2 parts by mass, more preferably 0.5 to 1 part by mass with respect to 100 parts by mass of the toner. When the content is 0.5 parts by mass to 2 parts by mass, the following problems can be prevented.
・ Defects with poor hot offset resistance ・ Defects with poor gloss and low temperature fixability

<<< Release Agent >>>
The release agent is not particularly limited as long as it is used for ordinary toner, and can be appropriately selected depending on the intended purpose, but ester wax is preferable. Since the ester wax has low compatibility with a general polyester binder resin, it easily exudes to the surface at the time of fixing, exhibits high mold release property, and can secure high low temperature fixability.
As the ester wax, it is preferable to use a synthetic monoester wax. Examples of synthetic monoester waxes include monoester waxes synthesized from long-chain linear saturated fatty acids and long-chain linear saturated alcohols. The long-chain linear saturated fatty acid is represented by the general formula Cn H _{2n + 1} COOH, and is preferably about n = 5 to 30, and more preferably n = 13 to 29. The long-chain linear saturated alcohol is represented by C _n H _{2n + 1} OH, and is preferably about n = 5 to 30, and more preferably n = 14 to 30.
Here, specific examples of the long-chain linear saturated fatty acid include capric acid, undesic acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecanoic acid, tetradecanoic acid, stearic acid, nonadecanoic acid, and aramonic acid. Examples thereof include behenic acid, lignoseric acid, cellotic acid, heptacosanoic acid, montanic acid and melicic acid. On the other hand, specific examples of long-chain linear saturated alcohols include amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, and myristyl alcohol. Examples thereof include pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecil alcohol, eicosyl alcohol, ceryl alcohol and heptadecanool, and have substituents such as lower alkyl group, amino group and halogen. You may.

The content of the ester wax is preferably 4 parts by mass to 8 parts by mass, and more preferably 5 parts by mass to 7 parts by mass with respect to 100 parts by mass of the toner. When the content is 4 parts by mass to 8 parts by mass, the following problems can be prevented.
-Problems that the exudation to the surface at the time of fixing is insufficient, the mold release property is deteriorated, and the low temperature fixing property and the high temperature offset resistance are deteriorated.
-The problem is that the amount of mold release agent deposited on the toner surface increases, the storage stability as toner deteriorates, and the filming property to the photoconductor etc. deteriorates.

<<< Wax Dispersant >>>
The wax dispersant is not particularly limited as long as it is used for ordinary toner, and can be appropriately selected depending on the intended purpose. However, a resin containing a polycondensation resin unit and an addition polymerization resin unit (also referred to as a hybrid resin). ) Is preferable.
The polycondensation resin unit is a polymer unit obtained by polymerizing an alcohol component containing an aromatic alcohol component as a monomer and a carboxylic acid component containing an aliphatic dicarboxylic acid having 9 or more and 14 or less carbon atoms. ..
The addition polymerization resin unit is a unit of a polymer obtained by polymerizing a component containing styrene, acrylic acid and an acrylic acid derivative as a monomer.

The aromatic alcohol component is not particularly limited and may be appropriately selected depending on the intended purpose, but a compound represented by the following general formula (1) is preferable. The alcohol component may contain a polyhydric alcohol other than the aromatic alcohol component.

前記一般式（１）中、Ｒ_１及びＲ_２は、エチレン基、プロピレン基等の炭素数２～４のアルキレン基である。Ｒ_３及びＲ_４は、水素原子、炭素数１～６の直鎖アルキル基、又は分岐状アルキル基であり、例えば、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｔ－ブチル基、ヘキシル基、などが挙げられる。また、ｘ及びｙは、正の整数であり、その和は１～１６、特に好ましくは２～６である。

In the general formula (1), R ₁ and R ₂ are alkylene groups having 2 to 4 carbon atoms such as an ethylene group and a propylene group. R ₃ and R ₄ are a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, or a branched alkyl group, and are, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and a t-butyl group. , Hexyl group, etc. Further, x and y are positive integers, and the sum thereof is 1 to 16, particularly preferably 2 to 6.

As the aliphatic dicarboxylic acid having 9 or more and 14 or less carbon atoms, a linear alkanedicarboxylic acid is preferable. Examples of the linear alkanedicarboxylic acid include azelaic acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid.
The carboxylic acid component may contain a polyvalent carboxylic acid compound other than the carboxylic acid component having an aliphatic dicarboxylic acid having 9 or more and 14 or less carbon atoms. Examples of such polyvalent carboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, alkyl groups having 1 or more and 30 or less carbon atoms, or An aliphatic dicarboxylic acid such as succinic acid substituted with an alkenyl group having 2 to 30 carbon atoms; an aromatic dicarboxylic acid such as phthalic acid, isophthalic acid and terephthalic acid; an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; Trimerit Examples thereof include trivalent or higher aromatic carboxylic acids such as acids, 2,5,7-naphthalentricarboxylic acids and pyromellitic acids, and acid anhydrides thereof; alkyl esters having 1 or more and 3 or less carbon atoms.

Compared with the polyester resin which is the binder resin of the toner of the present invention, the hybrid resin has good compatibility with general wax, so that the dispersed state of the wax tends to be small. In addition, the hybrid resin has a weak internal cohesive force and is superior in pulverizability as compared with the polyester resin. Therefore, even if the wax dispersion state is the same, the probability that the interface between the wax and the resin becomes a crushed surface is low as in the case of the polyester resin, and the wax existing on the surface of the toner particles can be suppressed, so that the toner can be used as a toner. It is possible to improve the heat-resistant storage stability of.
Further, the hybrid resin tends to have properties close to those of the polyester, and does not significantly impair the low temperature fixing property and the internal cohesive force of the polyester.

The content of the wax dispersant is preferably 8 parts by mass or less with respect to 100 parts by mass of the toner. By containing the wax dispersant, the effect of dispersing the wax can be obtained, and stable improvement in heat-resistant storage stability can be expected regardless of the manufacturing method. In addition, the wax diameter becomes smaller due to the dispersion effect of the wax, and the filming phenomenon on the photoconductor or the like can be suppressed.
When the content is 8 parts by mass or less, the amount of incompatible components with respect to the polyester resin increases and the dispersibility of the wax becomes too high. Therefore, the filming resistance is improved, but the surface of the wax at the time of fixing is improved. It is possible to prevent problems such as poor exudation to the surface and deterioration of low temperature fixing property and hot offset resistance.

<Characteristics of toner>
<< Volume Average Particle Diameter of Toner >>
The volume average particle size of the toner of the present invention is preferably 3 μm to 10 μm.
The volume average particle size of the toner is measured by various methods. For example, a Coulter Counter Multisizer III is used, and the measurement sample is dispersed by an ultrasonic disperser for 1 minute by adding the measurement toner to an electrolytic solution containing a surfactant. 50,000 pieces of the sample were measured and used as the volume average particle size.

<< Measurement of molecular weight of binder resin >>
The number average molecular weight and the weight average molecular weight of the binder resin are measured by various methods. For example, the molecular weight distribution of the THF-dissolved component is measured by a GPC (gel permeation chromatography) measuring device GPC-150C (Gel Permeation Chromatography) as follows. Can be measured by Waters).
Specifically, the measurement was carried out by the following method using a column (KF801 to 807: manufactured by Shodex Co., Ltd.). The column was stabilized in a heat chamber at 40 ° C., and THF as a solvent was flowed through the column at this temperature at a flow rate of 1 ml / min. After sufficiently dissolving 0.05 g of the sample in 5 g of THF, it is filtered through a pretreatment filter (pore size 0.45 μm chromatodisc (manufactured by Kurabo)), and finally the sample concentration is adjusted to 0.05 to 0.6% by weight. 50 to 200 μL of a THF sample solution of the resin is injected and measured. In measuring the weight average molecular weight Mw and the number average molecular weight Mn of the THF dissolved content of the sample, the molecular weight distribution of the sample is determined from the relationship between the logarithmic value of the calibration line prepared from several monodisperse polystyrene standard samples and the count number. Calculated.
As a standard polystyrene sample for preparing a calibration curve, PressureChemical
Co. Molecular weight is 6 × 10 ² , 2.1 × 10 ² , 4 × 10 ² , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8.6 It is appropriate to use the ones of × 10 ⁵ , 2 × 10 ⁶ and 4.48 × 10 ⁶ (or those manufactured by Toyo Soda Industries Co., Ltd.), and use at least 10 standard polystyrene samples. Use a sample. An RI (refractive index) detector is used as the detector.

<< Measurement of glass transition point (Tg) of binder resin >>
The glass transition point (Tg) in the present invention can be measured using, for example, a differential scanning calorimeter (DSC210, manufactured by Seiko Electronics Co., Ltd.). Specifically, 0.01 to 0.02 g of the sample is weighed in an aluminum pan, the temperature is raised to 200 ° C., and the sample cooled from that temperature to 20 ° C. is cooled to 20 ° C. The temperature rises at / minute. At that time, the temperature at the intersection of the extension of the baseline below the maximum endothermic temperature and the tangent line indicating the maximum slope from the rising portion of the peak to the peak of the peak was defined as the glass transition point.

<Toner manufacturing method>
The toner of the present invention can be obtained by externally adding the externalizing agent to the toner matrix particles.
The toner matrix particles can be obtained by various production methods such as a pulverization method and a polymerization method (suspension polymerization, emulsion polymerization, dispersion polymerization, emulsification aggregation, emulsification association, etc.).
Next, the inorganic fine particles are externally added to the toner matrix particles. By mixing and stirring the toner matrix particles and the inorganic fine particles using mixers, the inorganic fine particles, which are external additives, are coated on the surface of the toner matrix particles while being crushed.
The mixing device that can be used is not particularly limited as long as the powder can be mixed, and a known device can be used. Examples include mixers. It is preferable that these mixing devices are equipped with a jacket or the like to control the internal temperature.
The strength of adhesion of the inorganic fine particles to the surface of the toner matrix can be controlled by changing the peripheral speed of the rotating blades of the mixing device or changing the mixing / stirring time. Further, when the inorganic fine particles are externally added while applying heat to the inside of the mixing device, the surface is softened and the inorganic fine particles can be embedded in the surface of the toner base, so that the adhesion strength to the surface of the toner base can be controlled.
In the present invention, the release rate of silica can be controlled by adjusting the total external addition time (stirring time). In particular, in order to set the silica release rate to 40% or more and 80% or less, it is preferable to set the mixing time to 8 minutes to 24 minutes.

<Developer>
The developer of the present invention contains at least the toner and, if necessary, other components such as carriers which are appropriately selected.
Therefore, it is possible to stably form a high-quality image with excellent transferability and chargeability. The developer may be a one-component developer or a two-component developer, but when used in a high-speed printer or the like corresponding to the improvement in information processing speed in recent years, the life is long. A two-component developer is preferable because it improves.

The carrier can be appropriately selected depending on the intended purpose, and examples thereof include a magnetic carrier and a resin carrier.
The magnetic carrier is preferably magnetic fine particles. Examples of the magnetic fine particles include spinel ferrites such as magnetite and gamma iron oxide; spinel ferrites containing one or more kinds of metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.); barium ferrite and the like. Magnetoplanbite-type ferrite; iron or alloy particles having an oxide layer on the surface can be mentioned. Among these, ferromagnetic fine particles such as iron are particularly preferable when high magnetization is required.
The shape of the carrier may be granular, spherical, or needle-shaped. Further, in consideration of chemical stability, it is preferable to use magnetite, spinel ferrite containing gamma iron oxide, barium ferrite, or other magnetoplumbite-type ferrite. A resin carrier having a desired magnetization can also be used by selecting the type and content of the ferromagnetic fine particles. The magnetic property of the carrier at this time is preferably 30 to 150 emu / g for the magnetization strength at 1,000 oersted.
Such a resin carrier can be produced by spraying a melt-kneaded product of magnetic fine particles and an insulating binder resin with a spray dryer. Specifically, by reacting and curing a monomer or a prepolymer in an aqueous medium in the presence of magnetic fine particles, a resin carrier in which magnetic fine particles are dispersed in a condensed binder can be produced.
Positively or negatively charged fine particles or conductive fine particles can be fixed to the surface of the magnetic carrier, or a resin can be coated to control the chargeability.
Silicone resin, acrylic resin, epoxy resin, and fluororesin are used as the surface coating material, and positive or negatively charged fine particles or conductive fine particles can be included in the coating, but silicone resin and acrylic resin can be used. preferable.

The mixing ratio of the electrophotographic toner of the present invention and the magnetic carrier is preferably 2% by mass to 10% by mass as the toner concentration.

(Toner storage unit)
The toner accommodating unit in the present invention means a unit accommodating toner in a unit having a function of accommodating toner. Here, examples of the toner storage unit include a toner storage container, a developer, and a process cartridge.
The toner container is a container that contains toner.
A developer has a means for accommodating and developing toner.
The process cartridge is a cartridge in which at least an electrostatic latent image carrier (also referred to as an image carrier) and a developing means are integrated, toner is stored, and the process cartridge is removable from the image forming apparatus. The process cartridge may further include at least one selected from charging means, exposure means, and cleaning means.
By mounting the toner accommodating unit of the present invention on an image forming apparatus to form an image, it is possible to prevent contamination of the photoconductor, and by taking advantage of the characteristics of the toner for electrophotographic photography having excellent durability, long-term image stability can be achieved. It has and can form high quality and high definition images.

(Image forming device and image forming method)
The image forming apparatus of the present invention has at least an electrostatic latent image carrier, an electrostatic latent image forming means, and a developing means, and further has other means, if necessary.
The image forming method according to the present invention includes at least an electrostatic latent image forming step and a developing step, and further includes other steps as necessary.
The image forming method can be suitably performed by the image forming apparatus, the electrostatic latent image forming step can be preferably performed by the electrostatic latent image forming means, and the developing step is the developing means. The other steps can be more preferably performed by the other means.
The image forming apparatus of the present invention more preferably includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image carrier. A developing means provided with toner, which develops the electrostatic latent image formed on the body with toner to form a toner image, and a toner image formed on the electrostatic latent image carrier are recorded as a recording medium. It includes a transfer means for transferring to the surface and a fixing means for fixing the toner image transferred to the surface of the recording medium.
Further, the image forming method of the present invention more preferably includes an electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier and the said one formed on the electrostatic latent image carrier. A development step of developing an electrostatic latent image with toner to form a toner image, a transfer step of transferring a toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and the recording. It includes a fixing step of fixing the toner image transferred to the surface of the medium.
The toner is used in the developing means and the developing process. It is preferable to form the toner image by using a developer containing the toner and, if necessary, other components such as carriers.

<Electrostatic latent image carrier>
The material, structure, and size of the electrostatic latent image carrier (hereinafter, also referred to as “photoreceptor”) are not particularly limited and may be appropriately selected from known materials. Examples thereof include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalopolymethine.

<Electrostatic latent image forming means>
The electrostatic latent image forming means is not particularly limited as long as it is a means for forming an electrostatic latent image on the electrostatic latent image carrier, and can be appropriately selected depending on the intended purpose. Examples thereof include a means having at least a charging member for charging the surface of the electrostatic latent image carrier and an exposure member for exposing the surface of the electrostatic latent image carrier in an image manner.

<Development means>
The developing means is not particularly limited as long as it is a developing means including toner that develops the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image, depending on the purpose. Can be selected as appropriate.

<Other means>
Examples of the other means include transfer means, fixing means, cleaning means, static elimination means, recycling means, control means and the like.

The image forming apparatus of the present invention preferably does not have a lubricant applying means. The lubricant applying means is a means for applying a lubricant to a photoconductor.

The lubricant refers to a lubricant applied to the surface of a photoconductor or the like. Examples of the lubricant include zinc stearate and the like.
The purpose of applying the lubricant is, for example, the following.
-By lowering the coefficient of friction μ, the behavior of the cleaning blade edge is stabilized and the cleaning means is assisted.
-Protects the surface of the photoconductor from the charging current when an AC voltage is applied to the charging roller.
-By scraping the lubricant applied to the surface of the image carrier using a cleaning blade, it is possible to suppress the adhesion of toner components to the image carrier and the contamination by external additives and paper.
As a method of applying the lubricant, for example, there is a method of applying the lubricant on the surface of the image carrier with a brush roller. be able to.

Generally, in an image forming apparatus excluding the lubricant applying means, the behavior of the cleaning blade edge is not stable, which causes cleaning failure, and the cleaning blade is in direct contact with an image carrier or the like, so that surface wear increases. ..
However, in the present invention, since the external additive has high deformability, the above-mentioned cleaning failure is unlikely to occur.

Next, one embodiment of the method of forming an image by the image forming apparatus of the present invention will be described with reference to FIG.
FIG. 2 is a schematic configuration diagram of an example of the image forming apparatus. Around the photoconductor drum (hereinafter referred to as a photoconductor) 110 as an image carrier, a charging roller 120 as a charging device, an exposure device 130, a cleaning device 160 having a cleaning blade, a static elimination lamp 170 as a static elimination device, and development An apparatus 140 and an intermediate transfer body 150 as an intermediate transfer body are arranged. The intermediate transfer body 150 is suspended by a plurality of suspension rollers 151, and is configured to travel in an endless manner in the direction of an arrow by a driving means such as a motor (not shown). A part of the suspension roller 151 also serves as a transfer bias roller that supplies a transfer bias to the intermediate transfer body, and a predetermined transfer bias voltage is applied from a power source (not shown). Further, a cleaning device 190 having a cleaning blade of the intermediate transfer body 150 is also arranged. Further, a transfer roller 180 is disposed as a transfer means for transferring the developed image to the transfer paper 1100 as the final transfer material facing the intermediate transfer body 150, and the transfer roller 180 is subjected to transfer bias by a power supply device (not shown). Will be supplied. A corona charger 152 as a charge applying means is provided around the intermediate transfer member 150.

The developing apparatus 140 includes a developing belt 141 as a developing agent carrier, a black (hereinafter referred to as Bk) developing unit 145K, a yellow (hereinafter referred to as Y) developing unit 145Y, and magenta (hereinafter referred to as magenta) arranged around the developing belt 141. It is composed of a developing unit (called magenta) 145M and a cyan (hereinafter referred to as C) developing unit 145C. Further, the developing belt 141 is stretched over a plurality of belt rollers and is configured to travel in an endless manner in the direction of an arrow by a driving means such as a motor (not shown). It moves at almost the same speed.
Since the configuration of each developing unit is common, the following description will be given only for the Bk developing unit 45K, and for the other developing units 145Y, 145M and 145C, the parts corresponding to those in the Bk developing unit 145K in the drawing will be described. Y, M, and C are added after the numbers assigned to those in the unit, and the description thereof will be omitted. The Bk developing unit 145K is arranged so as to immerse a developing tank 142K containing a high-viscosity and high-concentration liquid developer containing toner particles and a carrier liquid component, and a lower portion thereof in the liquid developer in the developing tank 142K. It is composed of a pumping roller 143K and a coating roller 144K in which the developer pumped from the pumping roller 143K is thinned and applied to the developing belt 141. The coating roller 144K has conductivity, and a predetermined bias is applied from a power source (not shown).

Subsequently, the operation of the image forming apparatus according to the present embodiment will be described. In FIG. 2, the photoconductor 110 is uniformly charged by the charging roller 120 while being rotationally driven in the direction of the arrow, and then the reflected light from the document is image-projected onto the photoconductor 110 by an optical system (not shown) by the exposure apparatus 130. Form an electrostatic latent image. This electrostatic latent image is developed by the developing device 140 to form a toner image as a microscopic image. The developer layer on the developing belt 141 is peeled off from the developing belt 141 in a thin layer state by contact with the photoconductor in the developing region, and shifts to a portion on the photoconductor 110 where a latent image is formed. The toner image developed by the developing device 140 is transferred to the surface of the intermediate transfer body 150 at the contact portion (primary transfer region) between the photoconductor 110 and the intermediate transfer body 150 moving at a constant velocity (primary transfer region). Transcription). When performing transfer in which three colors or four colors are superimposed, this step is repeated for each color to form a color image on the intermediate transfer body 150.
The corona charger 152 for applying a charge to the superposed toner image on the intermediate transfer body is installed on the downstream side of the contact facing portion between the photoconductor 110 and the intermediate transfer body 150 in the rotation direction of the intermediate transfer body 150. It is installed at a position on the upstream side of the contact facing portion between the intermediate transfer body 150 and the transfer paper 1100. Then, the corona charger 152 imparts a true electric charge having the same polarity as the charging polarity of the toner particles forming the toner image to the toner image, and the electric charge sufficient for good transfer to the transfer paper 1100. To the toner image. After being charged by the corona charger 152, the toner image is collectively transferred onto the transfer paper 1100 conveyed in the direction of the arrow from the paper feed section (not shown) by the transfer bias from the transfer roller 180 (secondary transfer). .. After that, the transfer paper 1100 to which the toner image is transferred is separated from the photoconductor 110 by a separation device (not shown), fixed by a fixing device (not shown), and then discharged from the device. On the other hand, in the photoconductor 110 after transfer, the untransferred toner is recovered and removed by the cleaning device 160, and the residual charge is removed by the static elimination lamp 170 in preparation for the next charge. Color images are usually formed of four colored toners. One to four toner layers are formed in one color image. The toner layer passes through primary transfer (transfer from the photoconductor to the intermediate transfer belt) and secondary transfer (transfer from the intermediate transfer belt to the sheet).

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. However, "part" represents "mass part" unless otherwise specified.

<Manufacturing of polyester resin>
258 parts of bisphenol A propylene oxide 2 mol adduct, 1,344 parts of bisphenol A ethylene oxide 2 mol adduct, 800 parts of terephthalic acid, and a condensation catalyst in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube. 1.8 parts of tetrabutoxytitanate was added as a catalyst, and the mixture was reacted at 230 ° C. for 6 hours while distilling off the generated water under a nitrogen stream. Next, the reaction was carried out under a reduced pressure of 5 mmHg to 20 mmHg for 1 hour, cooled to 180 ° C., 10 parts of trimellitic anhydride was added, and the weight average molecular weight was 30,000 and the number average molecular weight was reduced to 5 mmHg to 20 mmHg. Was reacted until the amount reached 2,300 to obtain a polyester resin.

<Manufacturing of monoester wax>
In a 1 liter four-necked flask equipped with a thermometer, a nitrogen introduction tube, a stirrer and a cooling tube, 50 parts by mass of cellotic acid and 50 parts by mass of palmitic acid as a fatty acid component, and 100 parts by mass of an alcohol component. A monoester wax having a melting point of 70.5 ° C. is charged with ceryl alcohol so as to have a total mass of 500 g, and the reaction is carried out at normal pressure for 15 hours or more while distilling off the reactant at 220 ° C. under a nitrogen stream. Got

<Manufacturing of external additives>
<< Manufacturing of External Additive 1 >>
The fumed silica used in the external additive 1 was produced by a burner combustion method (chemical flame) of a flammable gas, and tetrachlorosilane was used as a raw material by the following reaction.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl
Tetrachlorosilane was mixed with hydrogen and air in advance and supplied from the upper end of a cylindrical reactor using a multi-tube burner to carry out a combustion reaction to obtain fumed silica.
The gas mixing ratio was adjusted so that the volume ratio of tetrachlorosilane, hydrogen gas, and air was 1: 5: 14.

The obtained fumed silica was crushed in the order of a roll crusher crusher and a bead mill type crusher to obtain silica particles.
The roll crusher crusher performed coarse crushing under the conditions of a roll gap of 0.2 mm and a roll rotation speed of 250 rpm.
The obtained dry powder was classified using a vibrating sieve having an opening of 25 μm and 75 μm to obtain a silica powder having a volume average particle size: D50 of 45 μm.

Water and a dispersant are added to the silica powder obtained by the above method to adjust the silica particle slurry so that the concentration becomes 15%, and then using a bead mill type crusher, the rotor rotation speed is about 5 hours at 3,600 rpm. A crushing process was performed.
At this time, 100 g of beads having a diameter of 500 μm was used, and the amount of slurry was 1,500 mL.
The slurry thus obtained was spray-dried using a spray dryer at a slurry supply amount of 1 L / h, a spray pressure of 2 kg / cm ² , and a hot air temperature of 150 ° C. to obtain silica particles.

2 kg of silica particles obtained as described above are placed in a fluidized layer reactor and supplied to a fluidized layer reactor heated to 450 ° C. at 8 g / min of dimethyldichlorosilane for 40 minutes using nitrogen to treat the surface for hydrophobicity. By applying the mixture, an external preparation 1 having a volume average particle size of 163 nm and a BET specific surface area of 101 m ² / g was obtained.

<Measurement of external additive particles>
The particles were observed with respect to the produced external additive alone, and the particle size distribution was measured.
The specific measurement procedure is the same as the method described in the measurement of the particle size / area ratio of the free external additive described later.
The BET specific surface area was measured using a nitrogen adsorption method (Macsorb model-1201, manufactured by Mountech).

<< Manufacture of external additives 2, 3, 5, 7, 8 and 9 >>
In the production of the external additive 1, the external additives 2, 3, and 5 are the same as those of the external additive 1 except that the combustion temperature and the crushing time using the bead mill type crusher are changed as shown in Table 1. , 7, 8 and 9 were obtained.

<< Manufacturing of External Additive 4 >>
Commercially available silica fine particles (HSP-160A: manufactured by Fuso Chemical Industry Co., Ltd.) were used as the external additive 4.

<< Manufacturing of External Additive 6 >>
Commercially available silica fine particles (HDK H 1303: manufactured by Clariant) were used as the external additive 6.

<< Manufacturing of External Additive 10 >>
Commercially available silica fine particles (UFP-35HH: manufactured by Denki Kagaku Kogyo Co., Ltd.) were used as the external additive 10.

<< Manufacture of External Additive 11 >>
Commercially available titanium oxide fine particles (ST-550: manufactured by Titan Kogyo Co., Ltd.) were used as the external additive 11.

<Manufacturing of toner>
<< Manufacture of Toner Mother Particle 1 >>
-Polyester resin (Mw: 30,000, Mn: 2,300) 90.0 parts-Styrene acrylic copolymer (EXD-001 manufactured by Sanyo Chemical Industries, Ltd.)
(Tg68 ℃, Mw13,000) 5.0 parts ・ Monoester wax (mp70.5 ℃) 5.0 parts ・ Salicylic acid derivative zirconium salt (trade name: TN-105, manufacturing company name: manufactured by Hodogaya Chemical Co., Ltd.) 0 .9 parts After premixing the above toner raw materials with a Henshell mixer (FM20B manufactured by Nippon Coke Industries Co., Ltd.), a temperature of 100 ° C to 130 ° C is used with a uniaxial kneader (Buss, Conida kneader). Melted and kneaded in. The obtained kneaded product was cooled to room temperature and then roughly pulverized to 200 μm to 300 μm with a rotoplex. Next, using a counter jet mill (manufactured by Hosokawa Micron Co., Ltd., 100AFG), finely pulverized while appropriately adjusting the pulverized air pressure so that the weight average particle size is 5.4 ± 0.3 μm, and then an air flow classifier (100AFG). EJ-LABO manufactured by Matsubo Co., Ltd.), adjust the louver opening appropriately so that the weight average particle size is 5.8 ± 0.4 μm and the weight average particle size / number average particle size ratio is 1.25 or less. While classifying, the toner matrix particles 1 were obtained.

<< Manufacture of Toner Mother Particles 2 >>
In the production of the toner matrix particles 1, the toner matrix particles 2 were produced by the same procedure as that of the toner matrix particles 1 except that the material type and amount used were changed as follows.
・ Polyester resin (Mw: 30,000, Mn: 2,300) 95.0 parts ・ Monoester wax (mp70.5 ° C) 5.0 parts ・ Salicylic acid derivative zirconium salt (trade name: TN-105, manufacturing company name) : Made by Hodogaya Chemical Co., Ltd.) 0.9 copies

(Example 1)
1: 2.0 parts of external additive was added to 1: 100 parts of toner matrix particles.
A Henschel mixer (FM20C / I manufactured by Nippon Coke Industries Co., Ltd.) is used for the mixing process of the toner matrix particles and the external additive 1, and the toner 1 is repeated 16 times at a rotation speed of 3,176 rpm for 1 min for rotation and 1 min for stopping. Got (Total mixing time 20 min)

(Example 2)
In the production of the toner 1, the toner 2 was produced in the same manner as the toner 1 except that the number of times of repeating the rotation 1 min and the stop 1 min at a rotation speed of 3,176 rpm was changed to 9 times by using a Henschel mixer.

(Example 3)
In the production of the toner 1, the toner 3 was produced in the same manner as the toner 1 except that the number of times of repeating the rotation 1 min and the stop 1 min at a rotation speed of 3,176 rpm was changed to 6 times by using a Henschel mixer.

(Example 4)
In the production of the toner 1, the toner 4 was produced in the same manner as the toner 1 except that the external additive 2 was used.

(Example 5)
In the production of the toner 1, the toner 5 was produced in the same manner as the toner 1 except that the external additive 3 was used.

(Example 6)
In the production of the toner 1, the toner 6 was produced in the same manner as the toner 1 except that the external additive 4 was used.

(Example 7)
In the production of the toner 1, the toner 7 was produced in the same manner as the toner 1 except that the external additive 5 was used.

(Example 8)
In the production of the toner 1, the toner 8 was produced in the same manner as the toner 1 except that the toner matrix particles 2 were used.

(Example 9)
The toner 9 was produced in the same manner as the toner 1 except that 1: 2.0 parts of the external additive and 11 parts of the external additive were added to 1: 100 parts of the toner matrix particles.

(Comparative Example 1)
In the production of the toner 1, the toner 10 was produced in the same manner as the toner 1 except that the number of times of repeating the rotation 1 min and the stop 1 min at a rotation speed of 3,176 rpm was changed to 3 times by using a Henschel mixer.

(Comparative Example 2)
In the production of the toner 1, the toner 11 was produced in the same manner as the toner 1 except that the number of times of repeating 1 min of rotation and 1 min of stop at a rotation speed of 3,176 rpm was changed to 25 times using a Henschel mixer.

(Comparative Example 3)
In the production of the toner 1, the toner 12 is the same as the toner 1 except that the external additive 6 is used and the number of times of repeating the rotation 1 min and the stop 1 min at a rotation speed of 3,176 rpm is changed to 12 times. Manufactured.

(Comparative Example 4)
In the production of the toner 1, the toner 13 was produced in the same manner as the toner 1 except that the external additive 7 was used.

(Comparative Example 5)
In the production of the toner 1, the toner 14 was produced in the same manner as the toner 1 except that the external additive 8 was used.

(Comparative Example 6)
In the production of the toner 1, the toner 15 was produced in the same manner as the toner 1 except that the external additive 9 was used.

(Comparative Example 7)
In the production of the toner 1, the toner 16 was produced in the same manner as the toner 1 except that the external additive was changed to 6: 1.0 part and the external additive was changed to 10: 1.0 part (the external additive 6 and the toner 1). The external additive 10 was added in the same amount by mass).

(Comparative Example 8)
In the production of the toner 1, the toner 17 was produced in the same manner as the toner 1 except that the addition was changed to 1: 1.0 part of the external additive and 10: 1.0 part of the external additive (external additive 1 and the outside). Additive 10 was added in the same amount by mass).

<Measurement of silica release rate>
The silica release rate was measured as follows.
(1) Preparation of surfactant solution 5.00 g of a surfactant (Neugen ET-165: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and 300 mL of distilled water were added to a 500 mL beaker and dissolved by ultrasonic waves. Then, it was transferred to a 1,000 mL volumetric flask and made up with a volumetric flask to obtain a surfactant solution.

(2) Preparation of toner dispersion solution 3.75 g of toner was weighed. 50 mL of the surfactant solution was added to a 100 mL screw tube. For the surfactant solution, bubbles were removed with a dropper or the like so as not to foam, and the solution was measured with a measuring cylinder.
After applying the surfactant solution to the wall surface, toner was added and gently turned up, down, left and right.
The toner was stirred with a ball mill for 10 minutes (60 rpm) so that it would be compatible with the detergent solution.
The special jig cuts a 2L wide-mouthed bottle and partitions it with cardboard so that five screw pipes can be inserted.

(3) Applying ultrasonic energy Add 50 mL of pure water to the mini cup, and set the tip of the ultrasonic homogenizer (trade name homogenizer, type VCX750, CV33, manufactured by SONICS & MATERIALS Co., Ltd.) so that it is 1 cm from the bottom of the mini cup. The output was adjusted so that the ultrasonic energy was 40 W.
Since the intensity fluctuates when sound wave energy is applied, the output is set in advance so as not to exceed 40 W. The fluctuation range is allowed up to 30W, but it should not be less than this.
The toner dispersion solution was transferred from the screw tube to the mini cup and ultrasonic energy was applied at 40 W for 1 minute.

(4) Separation of free additive The toner dispersion solution to which ultrasonic waves were applied was transferred to a 100 mL centrifuge tube and centrifuged at 2000 rpm for 2 minutes. This was done by putting two 50 mL ointment bottles in a stainless steel container and setting a centrifuge tube in the ointment bottle). After centrifugation, the supernatant of the centrifuge tube was set aside for observation.

(5) Filtration 30 mL of pure water was added to the centrifuge tube, and the precipitated toner was stirred with a spatula and poured into a funnel. Moisture was drawn by suction filtration, 30 mL of pure water was added to the centrifuge tube again, the completely precipitated toner was washed out, and the toner was poured into a funnel. The filter paper used is (trade name qualitative filter paper (No. 2, 110 mm, manufactured by Advantech Toyo Co., Ltd.).
After drying to some extent, the toner was once transferred to a beaker, 60 mL of pure water was added, and the mixture was gently stirred with a spatula. At this time, water was poured over the filter paper to remove the toner on the filter paper.
After drying, the toner was transferred to an aluminum cup and crushed finely with a spatula.

(6) Drying The aluminum cup containing the toner was stored in a constant temperature bath at 38 ° C. and dried for 8 hours or more.

(7) Measurement of X-rays The amount of the external additive contained in the toner after the liberation treatment obtained in the above (1) to (6) and the toner before the liberation treatment is quantified by the fluorescent X-ray method, and the following formula is used. The value obtained by substituting into is evaluated as the release rate of the external additive.
(Release rate of external additive) = (Amount of external additive contained in toner before release treatment-Amount of external additive contained in toner after release treatment) / (Amount of external additive contained in toner before release treatment) × 100

<Measurement of particle size / area ratio of free external additive>
In the external additive release rate measurement work, using the supernatant liquid separated after centrifugation ((4) in the external additive release rate measurement work), observe particles with a diameter equivalent to a circle of 50 nm or more, and perform free external addition. The particle size / area ratio of the agent was measured.
The measurement was performed using a transmission electron microscope (JEM-2100, JEOL Ltd.).
The observation sample was prepared by pasting the above supernatant liquid on a collodion membrane pasting mesh (Nisshin EM Co., Ltd.). Images were obtained using the obtained observation samples. The obtained image was binarized by image processing software A image (Asahi Kasei Engineering Co., Ltd.), and the equivalent circle diameter, particle area, and circumscribed circle area were calculated.
The above calculation is performed using the "circle equivalent diameter 2", "area", and "circumscribed circle diameter" obtained in the particle analysis mode of the image A.
The circle-equivalent diameter was obtained by converting the value obtained above into the value of the diameter, assuming that the value was due to the circular area.
As the particle area, the value of "area" obtained by binarization was used as it was.
The circumscribed circle area was calculated from the "circumscribed circle diameter" obtained by binarization.
The area ratio (circumscribed circle area / particle area) was obtained by dividing the "average circumscribed circle area" obtained above by the "average particle area".
For the volume average particle size, calculate the volume from the equivalent circle diameter obtained above using the same software, and divide the sum of the product of the particle diameter and the volume by the sum of the volumes ([(particle diameter x volume) of each measured particle). / Total volume of each measured particle]).
The details of the analysis conditions for this analysis are described below.
Binarization method (threshold value): Manual setting (visual)
Range specification: Yes Outer edge correction: No Hole filling: Yes Shrinkage separation: No The reason why the binarization threshold is set manually in the above is to distinguish between the unevenness of the toner surface and the external additive. In addition, when the contrast on the same image changes drastically when binarizing, the analysis range is specified near one particle, and the threshold value is set by observing the particle in one particle and the surrounding area.
The ratio of the particle area of particles with a circle equivalent diameter of 50 nm or more to the total particle area of the released external additive (the particle area ratio of particles with a circle equivalent diameter of 50 nm or more) is measured by [Circle equivalent diameter of 50 nm. It was calculated by the total of the above particle areas / the total of the particle areas of all the released particles].

Table 2 shows the silica release rates of the toners 1 to 17 and the observation results.

<< Manufacturing of two-component developer >>
<Creation of carrier>
・ Silicone resin (organo straight silicone) 100 parts ・ Toluene 100 parts ・ γ- (2-Aminoethyl) aminopropyltrimethoxysilane 5 parts ・ Carbon black 10 parts Disperse the above mixture for 20 minutes with a homomixer and coat layer. A forming solution was prepared. This coating layer forming liquid was applied to a spherical ferrite surface having an average particle size of 35 μm using a fluidized bed type coating device so that the average film thickness was 0.20 μm to form an internal resin layer. Using a fluidized bed type coating device, the temperature inside the fluidized bed was controlled to 70 ° C. for coating and drying. The obtained carrier was fired in an electric furnace at 180 ° C. for 2 hours, and then the particle size was adjusted by sieving to obtain a carrier.

The prepared carrier and toner 1 were uniformly mixed and charged at 48 rpm for 5 minutes using a turbobler mixer (manufactured by Willy et Bacoffen (WAB)) to prepare a two-component developer 1. The mixing ratio of the toner and the carrier was adjusted to the toner concentration of the initial developer of the evaluator: 4% by mass.

In the production of the two-component developer 1, the two-component developer 2 to 17 were produced in the same manner as the two-component developer 1 except that the toner 1 was replaced with the toners 2 to 17, respectively.

The obtained two-component developer was set in an evaluation machine from which the lubricant coating mechanism was removed from a digital full-color multifunction device (MP C306, manufactured by Ricoh Co., Ltd.), and the following evaluation was performed. The evaluation results are shown in Table 3.

<Prevention of photoconductor contamination>
The 5% image density chart was visually evaluated for the amount of adhered components adhering to the photoconductor after 2,000 images were output under normal temperature and humidity conditions according to the following evaluation criteria.
◎: No adhesion at all ○: Slightly cloudy traces and fixed matter were observed △: Cloudy streaks and slight fixed matter can be confirmed, but not output in the image ×: Very large cloudy area and fixed matter Or, it is output on the image such as transfer failure.

<Durability>
After outputting 40,000 images of the 5% image density chart under high temperature and high humidity conditions (30 ° C., 80%), 100 images were observed and evaluated according to the following evaluation criteria.
◯: No adhesion at all Δ: 1 piece / sheet or less of streak-like or spot-like fixed matter ×: 1 piece / sheet or more of streak-like or spot-like fixed matter

Examples of aspects of the present invention are as follows.
<1> An electrophotographic toner containing a toner matrix particle containing a binder resin and an external additive containing silica, wherein the external agent satisfies the following (1) to (4). It is an electrophotographic toner characterized by this.
(1) The release rate of the silica is 40% or more and 80% or less.
(2) The liberated external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
(3) The volume average particle diameter of the particles having a diameter equivalent to a circle of 50 nm or more is 100 nm or more and 160 nm or less.
(4) The ratio (circumscribed circle area / particle area) between the circumscribed circle area and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 1.80 or more and 3.00 or less.
<2> The electrophotographic toner according to the previous term <1>, wherein the ratio of the particle area of the particles having a diameter equivalent to a circle of 50 nm or more is 30% or more with respect to the total particle area of the released external additive. ..
<3> The toner for electrophotographic according to any one of <1> to <2>, wherein the particles having a diameter equivalent to a circle of 50 nm or more are aggregate particles.
<4> The toner for electrophotographic according to any one of <1> to <3>, wherein the release rate of the silica is 40% or more and 60% or less.
<5> The ratio of the circumscribed circle area to the particle area (circumscribed circle area / particle area) of the particles having an equivalent circle diameter of 50 nm or more is 2.00 or more and 2.80 or less. The electrophotographic toner according to any one.
<6> The electrophotographic toner according to any one of <1> to <5>, wherein the electrophotographic toner further contains a mold release agent and a wax dispersant.
<7> The mold release agent is an ester wax.
The electrophotographic toner according to <6>, wherein the wax dispersant is a resin containing a polycondensation polymer unit and an addition polymerization resin unit.
<8> A toner storage unit containing the electrophotographic toner according to any one of <1> to <7>.
<9> Electrostatic latent image carrier and
An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier,
A developing means provided with toner, which develops the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image.
A transfer means for transferring a toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a transfer means.
The fixing means for fixing the toner image transferred to the surface of the recording medium is included.
The image forming apparatus is characterized in that the toner is the toner for electrophotographic according to any one of <1> to <7>.
<10> The image forming apparatus according to <9>, wherein the image forming apparatus does not have a lubricant applying means for applying a lubricant on the electrostatic latent image carrier.

The electrophotographic toners described in <1> to <7>, the toner accommodating unit described in <8>, and the image forming apparatus described in <9> to <10> have the above-mentioned problems in the prior art. It can be solved and the object of the present invention can be achieved.

110 Photoreceptor 120 Charging roller 160 Cleaning device

Japanese Unexamined Patent Publication No. 2008-145652 Japanese Patent No. 3596853 Japanese Unexamined Patent Publication No. 2007-264142 Japanese Unexamined Patent Publication No. 2009-229621 Japanese Unexamined Patent Publication No. 2006-030662 Japanese Patent No. 564464

Claims (8)

An electrophotographic toner containing a toner matrix particle containing a binder resin and an external additive containing silica, wherein the external agent satisfies the following (1) to (4), and the above-mentioned An electrophotographic toner, wherein the electrophotographic toner further contains a release agent and a wax dispersant.
(1) The release rate of the silica is 40% or more and 60 % or less.
(2) The liberated external additive contains particles having a diameter equivalent to a circle of 50 nm or more.
(3) The volume average particle diameter of the particles having a diameter equivalent to a circle of 50 nm or more is 110 nm or more and 150 nm or less.
(4) The ratio (circumscribed circle area / particle area) between the circumscribed circle area and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 1.80 or more and 2.80 or less. The electrophotographic toner according to claim 1, wherein the ratio of the particle area of the particles having a diameter equivalent to a circle of 50 nm or more is 30% or more with respect to the total particle area of the released external additive. The electrophotographic toner according to any one of claims 1 to 2, wherein the particles having a diameter equivalent to a circle of 50 nm or more are aggregated particles. The electron according to any one of claims 1 to 3, wherein the ratio (circumscribed circle area / particle area) between the circumscribed circle area and the particle area of the particles having a circle equivalent diameter of 50 nm or more is 2.00 or more and 2.80 or less. Photo toner. The mold release agent is an ester wax.
The electrophotographic toner according to any one of claims 1 to 4, wherein the wax dispersant is a resin containing a polycondensation resin unit and an addition polymerization resin unit. A toner storage unit containing the electrophotographic toner according to any one of claims 1 to 5. Electrostatic latent image carrier and
An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier,
A developing means provided with toner, which develops the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image.
A transfer means for transferring a toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a transfer means.
The fixing means for fixing the toner image transferred to the surface of the recording medium is included.
An image forming apparatus according to any one of claims 1 to 5, wherein the toner is an electrophotographic toner. The image forming apparatus according to claim 7, wherein the image forming apparatus does not have a lubricant applying means for applying a lubricant on the electrostatic latent image carrier.

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