JP5760331B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic photography and the like.

  In general, an electrophotographic method forms an electrostatic latent image on a photoconductive photoreceptor by various methods, and then visualizes the latent image using an electrostatic charge image developing toner (hereinafter abbreviated as “toner”). After that, there is a step of transferring the toner visible image onto a transfer material such as paper and fixing the toner image by heating or pressurizing. Various methods are known as these steps, and those suitable for each image forming process are employed.

  One of the typical toner manufacturing methods is a pulverization method that melts and mixes various materials such as binder resins, colorants, and charge control agents, and then pulverizes and classifies them into fine powders. In general, it is widely used regardless of color, monochrome, and various development methods. Further, in order to meet the recent demand for higher speed and higher image quality for electrophotography, research and development of wet toner is actively conducted. Since the wet toner is easier to control the particle size than the pulverized toner, it is possible to obtain toner mother particles having a small particle size suitable for high image quality. Further, since the toner can be encapsulated by controlling the particle structure, there is an advantage that a toner excellent in heat resistance and low-temperature fixability can be obtained.

  Regardless of whether it is a pulverized toner or a wet toner, the obtained toner base particles have an external addition step in which various additives are adhered or fixed to the surface of the toner base particles by stirring and mixing together with the toner base particles. Is normal. As a result, various physical properties such as chargeability and fluidity of the toner are improved or controlled.

  In general, when the charge amount of toner is low or the rising property of charge is poor, a toner that is insufficiently charged adheres to a portion that should originally be white, and a phenomenon that the background of an image becomes dirty, so-called fogging, occurs. Also, insufficient toner fluidity is not preferable because the amount supplied to the toner carrier is insufficient, causing defects such as fading of the image on the printing portion.

  Various external additives may be used in the external addition process depending on the target physical properties, but metal oxides such as silicon dioxide (silica), titanium oxide (titania), aluminum oxide (alumina), etc. Inorganic particles made of the above are used, and the type is appropriately selected according to the desired toner physical properties.

  In order to prevent the phenomenon that excessively charged toner particles are electrostatically strongly adhered to the latent image holding member and the toner is fused to the latent image holding member in a low humidity environment. A method of adding inorganic fine particles is shown (Patent Document 1). However, in the case of high humidity, the silica fine particles externally added to the toner are particularly affected by the humidity, and the charging of the entire toner may be reduced due to the influence. Further, the charge of the toner changes greatly in a humidity environment, and the charge of the toner is distributed and not uniform, which may cause problems such as fogging and a decrease in printing durability.

  Therefore, with the recent trend toward higher speed and higher printing durability, the electrostatic charge is excellent in charge rise and charge maintenance in all environments including high temperature and high humidity and low temperature and low humidity, and has little fog even after repeated use. Although development of toner for image development is desired, it is still insufficient.

JP 2001-318487 A

  The present invention is a toner containing at least silica particles and inorganic particles. By containing specific inorganic particles, the toner has a good charge rising property and a good charge amount level until the latter half of the printing durability. The present invention provides a toner that does not cause fogging or toner scattering in all environments including high humidity, low temperature and low humidity.

  The present inventor has repeatedly studied to solve the above problems, and has found that the above problems can be solved by containing specific inorganic particles. The present invention is based on this finding, and the gist of the present invention is as follows.

1. A toner for developing an electrostatic charge image, which is a negatively chargeable toner containing at least silica particles and inorganic particles, wherein the inorganic particles satisfy the following (1) to (3).
(1) The average primary particle size is 0.1 μm or more (2) The electric resistance value is 1 × 10 ⁺¹⁰ Ω · cm or less (3) Positive chargeability 2. The electrostatic image developing toner according to 1 above, wherein the ratio a / b of the addition amount (a) of the silica particles and the addition amount (b) of the inorganic particles is 10 or more.
3. 3. The toner for developing an electrostatic charge image according to 1 or 2 above, wherein the addition amount of the inorganic particles is 0.3 parts by mass or less with respect to 100 parts by mass of the toner base particles.
4. The toner for developing an electrostatic charge image according to any one of 1 to 3 above, wherein the inorganic particles are surface-treated.
5. 5. The electrostatic image developing toner according to any one of 1 to 4 above, wherein the toner has a volume median diameter of 4 μm or more and 8 μm or less.
6). 6. The toner for developing an electrostatic charge image according to any one of 1 to 5, wherein the toner has an average circularity of 0.955 or more and 0.985 or less.
7). 7. The electrostatic image developing toner according to any one of 1 to 6 above, which contains an organic acid metal salt.
8). 8. The electrostatic image developing toner according to any one of 1 to 7 above, which comprises a compound represented by the following general formula (4).
M1 y1 · M2 y2 · M3 x · (OH) 2 · Ax / n · mH 2 O ···· (4)
(Wherein M1 represents at least one divalent metal selected from the group consisting of Mg, Ca, Sr and Ba, and M2 represents a divalent metal selected from the group consisting of Zn, Cd, Pb and Sn. At least one species, M3 represents a trivalent metal, A represents an n-valent anion, and x, y1, y2 and m represent 0 <x ≦ 0.5, y1 + y2 = 1-x, An integer satisfying the relational expression of 0 ≦ m <2 is indicated, and the surface treatment is performed with higher fatty acids.)

  The toner of the present invention contains at least silica particles and inorganic particles other than silica particles. The method for containing the silica particles and the inorganic particles is not particularly limited, but it is preferably externally added to the toner base particles.

In order to prevent the phenomenon that the background of the image gets dirty and the so-called fogging is prevented, that is, the toner should be highly charged and the entire toner is uniformly charged. In addition, it is necessary that charging is maintained in all environments including high temperature and high humidity and low temperature and low humidity.
In the present invention, by containing at least silica particles and specific inorganic particles, the toner is highly charged, and the inorganic particles have a charge opposite to that of the toner even in a high humidity environment where the charge tends to be low. In this way, it is possible to solve the problems such as fogging and toner scattering in all environments by maintaining the high charge and further uniforming the charging of the whole toner with inorganic particles having a specific particle size and electric resistance. it can.

It is essential that the average primary particle size of the inorganic particles of the present invention is 0.1 μm or more. Among these, 0.15 μm or more is preferable, and 0.2 μm or more is particularly preferable. Moreover, it is preferable that it is 1 micrometer or less, and it is especially preferable that it is 0.5 micrometer or less.
If the average primary particle size is too large, the separation from the surface of the mother particle becomes excessive, and the effect of the present invention may not be maintained until the latter half of the printing durability. If the average primary particle size is too small, appropriate rolling or desorption on the surface of the mother particle is not achieved. The effect of the present invention may be difficult to obtain.
The average primary particle size of the inorganic particles of the present invention is measured by the method described in the examples.

It is essential that the electrical resistance value of the inorganic particles of the present invention is 1 × 10 ⁺¹⁰ Ω · cm or less. In particular, it is preferably 1 × 10 ⁺⁹ Ω · cm or less. Further, it is preferably 1 × ^{10 + 3} Ω · cm or more, and more preferably 1 × 10 ⁺⁶ Ω · cm or more. If the electrical resistance value is too large, in addition to the above-mentioned problems such as “fogging” and “local image density fluctuation of solid image” due to excessive charge / low charge of the specific toner particles described above. In some cases, the inorganic particles adhering to various members due to printing durability may cause a problem in charging control of the printing system and adversely affect the printed image. For example, if a small amount of the inorganic particles that could not be removed from the system by the cleaning unit of the organic photosensitive drum adheres to a contact-type charging roller that charges the organic photosensitive drum, charging is applied to the organic photosensitive drum. May cause image defects due to charging failure on the drum surface. On the other hand, if it is too small, charging of the toner particles inside the developing tank is leaked to lower the charge, so that image defects such as fogging tend to occur. The electrical resistance value is measured by the method described in the examples.

Although the method of making the inorganic particles of the present invention have a specific electric resistance value is not particularly limited, it can be adjusted by subjecting the inorganic particle base material constituting the core of the inorganic particles to surface treatment. The treatment method may be an aqueous phase or gas phase method. As the surface treatment agent, inorganic compounds and organic compounds can be used. Inorganic compounds include oxides such as silica, aluminum, zirconium, titanium, tin, antimony, and zinc, hydrous oxides, and phosphates. Organic compounds include polyols such as trimethylolpropane, trimethylolethane, ditrimethylolpropane, trimethylolpropane ethoxylate, pentaerythritol, monoethanolamine, monopropanolamine diethanolamine, dipropanolamine, triethanolamine, tripropanol Alkanolamines such as amines and their acetates, oxalates, tartrates, formates, benzoates and other organic acid derivatives, silane coupling agents, titanate coupling agents, silicone oils, silicone varnishes And hydrophobizing agents such as fluorine-based silane coupling agents, fluorine-based silicone oils, coupling agents having amino groups and quaternary aluminum bases, and modified silicone oils. The treatment agent and the treatment amount are selected in view of the electric resistance value and charging characteristics of the inorganic particle base material .

  The substrate of the inorganic particles of the present invention is not particularly limited as long as it is an inorganic material other than silica particles, and examples thereof include inorganic oxides such as titanium oxide (titania), aluminum oxide (alumina), and strontium titanate. In particular, titanium oxide is preferable from the viewpoint of electrical resistance and adhesion to various members. Moreover, it is essential that the average primary particle diameter of the base material of the inorganic particles of the present invention is 0.1 μm or more. Among these, 0.15 μm or more is preferable, and 0.2 μm or more is particularly preferable. Moreover, it is preferable that it is 1 micrometer or less, and it is especially preferable that it is 0.5 micrometer or less.

It is essential that the inorganic particles of the present invention are positively charged. The negatively charged property of the toner can be easily obtained by the adhesion and separation of the positively charged inorganic particles. Furthermore, when the separated inorganic particles come into contact with the member to which the positive charging agent is attached, the toner can receive negative charge as an auxiliary, and particularly when the toner itself deteriorates due to printing durability, the rising of the charge is caused. Auxiliary and charged can be maintained.

Since the inorganic particles of the present invention have large average primary particles, it is difficult to be completely fixed on the surface of the mother particles, and due to the stress caused by the stirring of the toner during printing, the rolling movement on the particle surface, the separation from the mother particle surface, Further, the detached inorganic particles adhere to the transport roller, developing sleeve, charging blade and the like. Thereby, it is possible to obtain a carrier effect due to rolling movement on the toner surface and separation from the surface of the mother particles. Further, when the separated inorganic particles come into contact with the member to which the positive charging agent is attached, the toner can receive negative charge as an auxiliary, and particularly when the toner itself deteriorates due to the printing durability, the rising of the charge is caused. Auxiliary and charged can be maintained.
In addition, since the electrical resistance value of the inorganic particles of the present invention is not more than a specific value, excessively high charging / low charging of the toner particles can be suppressed, and charging fluctuations due to use environment differences can be reduced. It is effective for.
As a result, in all environments including high temperature and high humidity and low temperature and low humidity, good toner charge start-up and charge maintenance can be secured from the initial stage to the second half of printing durability, and good toner that does not cause fogging or toner scattering can be obtained. Can be obtained.

The addition amount of the inorganic particles of the present invention must be 0.3 parts by mass or less with respect to 100 parts by mass of the toner base particles. Moreover, it is further more preferable that it is 0.2 mass part or less. Moreover, 0.02 mass part or more is preferable, and 0.05 mass part or more is especially preferable. If the amount of inorganic particles is too large, filming on the organic photoreceptor drum may occur. This is because the external additive is scraped off by the cleaning unit of the organic photosensitive drum and strongly adheres to the surface of the organic photosensitive drum when it is removed from the system, or because of the average particle size, It is presumed that this occurs due to innumerable scratches on the drum surface. On the other hand, if the amount is too small, it may be difficult to obtain the effects of the present invention.

The inorganic particles of the present invention are positively charged and are not particularly limited as long as they satisfy the conditions of the average primary particle diameter and the electric resistance value. However, those that are surface-treated with an inorganic compound have the effect of the present invention. It is preferable to obtain.
The inorganic compound used for the surface treatment and the surface treatment method are not particularly limited, but an inorganic compound such as aluminum, silicon, or zinc can be surface treated by a wet method. Aluminum is particularly preferable, and examples thereof include sodium aluminate, aluminum sulfate, aluminum nitrate, and aluminum chloride.
Moreover, you may perform the inorganic or / and organic surface treatment different from aluminum before and after an aluminum treatment as needed.

The silica particles of the present invention preferably have an average primary particle size of 10 nm or more. Furthermore, the average primary particle size is more preferably 20 nm or more. The average primary particle size is 50 nm
The following is preferable. If it is larger than the above range, it is not preferable because sufficient fluidity cannot be obtained, and if it is smaller than the above range, silica is embedded in the surface of the mother particle during printing, and in terms of quality maintenance such as fogging during printing. It is not preferable. The average primary particle size is measured by the method described in the examples.

The addition amount of the silica particles of the present invention is preferably 3 parts by mass or less, and more preferably 2 parts by mass or less with respect to 100 parts by mass of the toner base particles. Moreover, 1 mass part or more is preferable and 1.5 mass part or more is further more preferable. If there are too many silica particles, the amount of free silica that cannot be attached to the surface of the mother particles increases, and image defects such as fogging are liable to occur due to poor charge rise of the toner and enlargement of the charge amount distribution. On the other hand, if the amount is too small, sufficient toner fluidity cannot be ensured, and image defects such as poor solid uniformity occur, which is not preferable.
Further, when the addition amount of the silica particles of the present invention is a and the addition amount b of the inorganic particles, a / b that is the ratio thereof is preferably 10 or more. Furthermore, it is preferably 20 or more,
It is especially preferable that it is 30 or more. Moreover, it is preferable that it is 140 or less, and it is especially preferable that it is 100 or less. When the ratio is too large, excessive silica particles exist around the inorganic particles, and thus the effect of the present invention by the inorganic particles may be hindered by the silica particles. On the other hand, if the ratio is too small, the effects of the present invention such as fogging can be sufficiently obtained, but filming to the organic photosensitive drum may be caused.

Drum filming due to inorganic particles may be a concern due to factors of the hardware system such as the image forming apparatus and members. In particular, it tends to occur in the case of a system design in which stress is applied to the cleaning section such that the φ of the organic photosensitive drum is 24 mm or less or the process speed is 100 mm / sec or more. In the present invention, an organic acid metal salt may be contained in order to solve drum filming. By adding the organic acid metal salt, the load on the cleaning portion is reduced, and problems such as filming due to adhesion of inorganic particles can be avoided. This is because the organic acid metal salt forms a thin film on the surface of the organophotoreceptor drum and changes the characteristics of the drum surface, thereby reducing the adhesion of the released inorganic particles to the drum surface and removing it. It is presumed that the effect of the present invention can be obtained by facilitating and [2] reducing friction between the drum surface and the cleaning member.

  Although the organic acid metal salt of this invention is not specifically limited, For example, a zinc stearate is mentioned. The size is preferably a volume average particle size of 8 μm or less and the number of added parts is preferably 0.5 parts or less. When the particle size is increased or the addition amount is increased, the toner fluidity is lowered and image defects such as poor solid uniformity may be caused.

In the present invention, a compound represented by the following general formula (4) may be contained in order to prevent image defects due to contamination of the charging roller on the organic photosensitive drum.
Contamination to the charging roller on the organic photoconductor drum is likely to occur in systems where the load on the cleaning unit is such that the φ of the organic photoconductor drum is 24 mm or less, or the process speed is 100 mm / sec or more. The transfer residual material having a high electrical resistance value such as toner particles and free silica particles is not effectively removed from the system by the cleaning unit, and passes through the cleaning unit in a small amount, and the substance adheres to the charging roller. Occur.
The compound represented by the following general formula (4) of the present invention can reduce charging roller contamination. This is presumably because the compound represented by the general formula (4) accumulates in the cleaning portion and assists in scraping off the transfer residual material on the surface of the organic photosensitive drum.
M1 y1 · M2 y2 · M3 x · (OH) 2 · Ax / n · mH 2 O ···· (4)
In the formula, M1 represents at least one divalent metal selected from the group consisting of Mg, Ca, Sr and Ba, and M2 represents at least a divalent metal selected from the group consisting of Zn, Cd, Pb and Sn. 1 represents one, M 3 represents a trivalent metal, A represents an n-valent anion, and x, y 1, y 2 and m are 0 <x ≦ 0.5, y 1 + y 2 = 1−x, 0 An integer satisfying the relational expression of ≦ m <2 is shown, and it is surface-treated with higher fatty acids.

  In the present invention, the amount of the compound represented by the general formula (4) is preferably 0.5 parts by mass or less with respect to 100 parts by mass of the toner base particles. When the addition amount is increased, the toner fluidity is lowered, and image defects such as poor solid uniformity may be caused.

The method for producing the toner of the present invention is not particularly limited, and a toner obtained by a method such as a pulverization method or a wet method can be used.
The volume median diameter of the toner of the present invention is preferably 4 μm or more, and more preferably 5 μm or more. Moreover, it is preferable that it is 8 micrometers or less, and it is more preferable that it is 7 micrometers or less. If the volume median diameter of the toner is too large, the amount of charge per unit weight tends to decrease, and the possibility of fogging and toner scattering may increase. If it is too small, the amount of charge per unit weight Tends to be excessive, and may cause problems such as extreme image density reduction. The volume median diameter is measured by the method described in the examples.

The number% (Dns) of the toner having a particle diameter of 2.00 μm or more and 3.56 μm or less of the toner of the present invention is measured by the method described later, and is defined as that measured. In the toner of the present invention, the relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle size of 2.00 μm to 3.56 μm is 0.0517EXP (22.4 / Dv50) ≦ Dns is satisfied. In the present invention, “EXP” indicates “Exponential”. That is, the base of the natural logarithm, and the right side is the exponent.
The purpose of this relational expression is that the amount of fine powder increases as the volume median diameter (Dv) of the toner decreases, and when the Dv is 4.5 μm or less, the value of Dv becomes the particle size. In order to approach the region of 2.00 μm or more and 3.56 μm or less, the value of Dns increases exponentially. Such an area of 2.00 μm or more and 3.56 μm or less is an area expressed by a specified channel of Multisizer III manufactured by Coulter Counter.
In the present invention, the particles included in the particle diameter range of 2.00 μm to 3.56 μm is a particle size region that should be specifically excluded in the region of the volume median diameter of the toner particles of 4.0 to 8.0 μm. . The toner of the present invention that satisfies the above particle size distribution conditions provides high image quality, and is less contaminated even when a high-speed printer is used, and suppresses afterimage (ghost) and blurring (solid followability). Excellent cleaning performance. In addition, since the charge amount distribution is very sharp because the particle size distribution is sharp, particles with a small charge amount do not cause the white background portion of the image to be smeared or scattered to stain the inside of the apparatus, Particles having a large charge amount do not develop and do not adhere to members such as a layer regulating blade or a roller and cause image defects such as streaks and blurring.
That is, the amount of fine powder affects the image with the above relational expression as a boundary. When the value of Dns exceeds the right side, the fine powder causes a defect in the image. For example, fine powder accumulates on the cleaning blade, and afterimages, blurring, dirt, and the like are generated as image defects.

Since the image forming apparatus is designed to transfer particles having a specific charge amount, first, the particles having the specific charge amount are preferentially transferred to the OPC during electrostatic development. Particles exceeding the specific charge amount adhere to members and cause contamination and fluidity deterioration. On the other hand, particles that do not satisfy a specific charge amount accumulate in the cartridge and contaminate members and the like.
Here, the toner charge amount correlates with the particle size of the toner when the toner composition is the same. Generally, the smaller the particle size, the higher the charge amount per unit weight, and the larger the charge amount, the smaller the charge amount per unit weight. Become. That is, if a large amount of toner having a small particle size is present, the charge amount becomes too high, which causes excessive adhesion to a member or the like and deterioration of the toner fluidity. In the present invention, this toner is specified to be 3.56 μm or less. This 3.56 μm is a value defined for the channel of the measuring apparatus. On the other hand, the lower limit value was set to 2.00 μm because of the measurement limit of the measuring apparatus.

The average circularity of the toner base particles of the present invention is preferably 0.955 or more, and more preferably 0.960 or more. Moreover, it is preferable that it is 0.985 or less, and it is more preferable that it is 0.980 or less. If the circularity is too large, slipping in the cleaning part is likely to occur, and the image may be defective. On the other hand, if the circularity is too small, when the inorganic particles roll on the surface of the mother particles due to agitation by printing durability, the mother particles The effect of the present invention may not be maintained until the end. The circularity of the toner base particles of the present invention is measured by the method described in the examples.

  The method for producing the toner of the present invention is not particularly limited, and includes at least a binder resin and a colorant, and optionally includes a charge control agent, wax, other additives, and the like.

  In the present invention, as the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be appropriately used. For example, as a monomer, a polymerizable monomer having an acidic group (hereinafter sometimes simply referred to as an acidic monomer), a polymerizable monomer having a basic group (hereinafter simply referred to as a basic monomer) A polymerizable monomer having no acidic group or basic group (hereinafter, also referred to as other monomer) may be used. it can.

  When a toner is produced using an emulsion polymerization aggregation method, in the emulsion polymerization step, a polymerizable monomer is usually polymerized in an aqueous medium in the presence of an emulsifier. In supplying the monomer, each monomer may be added separately, or a plurality of types of monomers may be mixed in advance and added simultaneously. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or an emulsifier.

  As the acidic monomer, a polymerizable monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, a polymerizable monomer having a sulfonic acid group such as sulfonated styrene, Examples thereof include polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide. Examples of the basic monomer include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocyclic-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. And (meth) acrylic acid ester having an amino group. These acidic monomers and basic monomers may be used singly or as a mixture of a plurality of types, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, more preferably acrylic acid and / or methacrylic acid.

  The total amount of the acidic monomer and the basic monomer in 100 parts by mass of the total polymerizable monomers constituting the binder resin is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass. More preferably, it is 1 part by mass or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

  Examples of other polymerizable monomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene, methyl acrylate, Acrylic esters such as ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate -Methacrylic acid esters such as butyl, isobutyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylic De, N, N-dibutyl acrylamide, and the like, the polymerizable monomer may be used singly, or may be used in combination.

Furthermore, when the binder resin is a cross-linked resin, a polyfunctional monomer having radical polymerizability is used together with the above polymerizable monomer, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, Examples include diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and diallyl phthalate. It is also possible to use a polymerizable monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein and the like. Among these, radically polymerizable bifunctional polymerizable monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable. These polyfunctional polymerizable monomers may be used alone or as a mixture of plural kinds.

  When the binder resin is polymerized by emulsion polymerization, a known surfactant can be used as an emulsifier. As the surfactant, one or more surfactants selected from cationic surfactants, anionic surfactants, and nonionic surfactants can be used in combination.

  Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and examples of the anionic surfactant include And fatty acid soap such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and the like. Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  The amount of the emulsifier used in the present invention is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. In addition, these emulsifiers can be used as protective colloids, for example, one or more of partially or completely saponified polyvinyl alcohols such as polyvinyl alcohol and cellulose derivatives such as hydroxyethyl cellulose.

  The volume average particle diameter of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less, more preferably. Is desirably 1 μm or less. If the particle size is too small, it may be difficult to control the aggregation rate in the aggregation process. If it is too large, the particle size of the toner particles obtained by aggregation tends to be large, and a toner having the target particle size is obtained. May be difficult.

  In this invention, a well-known polymerization initiator can be used as needed, A polymerization initiator can be used 1 type or in combination of 2 or more types. For example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, and the like, and redox initiators combining these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide, 4,4 Water-soluble polymerization initiators such as' -azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydropeoxide, etc., and these water-soluble polymerization initiators as a component combined with a reducing agent such as ferrous salt Redox initiator systems, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, and the like are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

  In the present invention, a known chain transfer agent can be used as necessary, and specific examples include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane and the like. It is done. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by weight based on the polymerizable monomer.

Moreover, in this invention, a well-known suspension stabilizer can be used as needed. Specific examples of the suspension stabilizer include calcium phosphate, magnesium phosphate calcium hydroxide, magnesium hydroxide and the like. These may be used alone or in combination of two or more, and may be used in an amount of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.
Both the polymerization initiator and the suspension stabilizer may be added to the polymerization system at any time before, simultaneously with, or after the addition of the polymerizable monomer. You may combine.
In addition, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, and the like can be appropriately added to the reaction system.

  The toner obtained by the production method and apparatus of the present invention preferably contains a wax in order to impart releasability. Any wax can be used as long as it has releasability.

  Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate A plant wax such as hydrogenated castor oil carnauba wax; a ketone having a long chain alkyl group such as distearyl ketone; a silicone having an alkyl group; a higher fatty acid such as stearic acid; a long chain aliphatic alcohol such as eicosanol; Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as erythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax may be exposed on the surface after fixing, and stickiness may occur. On the other hand, if the melting point is too high, the fixability at low temperatures may be poor.

  As the wax compound species, higher fatty acid ester waxes are preferable. Specific examples of the higher fatty acid ester wax include, for example, behenyl behenate, stearyl stearate, stearate of pentaerythritol, montanic acid glyceride, etc. The esters are preferred. Moreover, as an alcohol component which comprises ester, a C10-30 thing is preferable in the case of monohydric alcohol, and a C3-C10 thing is preferable in the case of a polyhydric alcohol.

  The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner.

  In the present invention, the amount of the wax is preferably 1 part by mass or more per 100 parts by mass of the toner, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more. Moreover, it is preferable that it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less. If the wax content in the toner is too low, performance such as high-temperature offset may not be sufficient, while if it is too high, the blocking resistance may not be sufficient, or the wax may leak from the toner and contaminate the device. Sometimes.

A known colorant can be arbitrarily used as the colorant of the present invention. Specific examples of the colorant include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, Any known dyes and pigments such as disazo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is preferably used so as to be 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer primary particles.

  The blending of the colorant in the emulsion polymerization aggregation method is usually performed in an aggregation step. A dispersion of polymer primary particles and a dispersion of colorant particles are mixed to form a mixed dispersion, which is then aggregated to form a particle aggregate. The colorant is preferably used in a state of being dispersed in water in the presence of an emulsifier, and the volume average particle diameter of the colorant particles is 0.01 or more, more preferably 0.05 μm or more, and more preferably 3 μm or less. 1 μm.

  In the present invention, when a charge control agent is used, any known one can be used alone or in combination. For example, a quaternary ammonium salt, a basic or electron donating metal as a positive charge control agent. Substances such as metal chelates, metal salts of organic acids, metal-containing dyes, nigrosine dyes, amide group-containing compounds, phenolic compounds, naphthol compounds and their metal salts, urethane bond-containing compounds, Examples include acidic or electron-withdrawing organic substances.

  In addition, when the toner for developing an electrostatic image obtained by the production method of the present invention is used as a toner other than a black toner in a color toner or a full color toner, a charge control agent that is colorless or light in color and does not impair the color tone of the toner is used. It is preferable to use, for example, a quaternary ammonium salt compound as a positively chargeable charge control agent, a metal salt of salicylic acid or an alkylsalicylic acid with chromium, zinc, aluminum, a metal complex as a negatively chargeable charge control agent, Hydroxys such as metal salts of benzylic acid, metal complexes, amide compounds, phenolic compounds, naphthol compounds, phenolamide compounds, 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene] Naphthalene compounds are preferred.

  In the present invention, when a charge control agent is contained in the toner using the emulsion polymerization aggregation method, the charge control agent is added together with a polymerizable monomer or the like at the time of emulsion polymerization, or together with the polymer primary particles and the colorant. It can be blended by a method such as adding in the agglomeration step, or adding after the polymer primary particles and the colorant are aggregated to almost the target particle size. Among these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average particle size of 0.01 μm or more and 3 μm or less.

  The toner of the present invention may be produced by any polymerization method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method, and is not particularly limited.

  In the present invention, as a method for producing a suspension polymerization toner, a coloring agent, a polymerization initiator, and, if necessary, a wax, a polar resin, a charge control agent, a crosslinking agent, etc. in the above-mentioned binder resin monomer. An additive is added to prepare a monomer composition that is uniformly dissolved or dispersed. This monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, polymerization is performed by stirring to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. These are collected by washing and filtration, and dried to obtain toner mother particles. Further, if necessary, toner can be obtained by external addition or the like.

As a production method of the emulsion polymerization aggregation method, polymer primary particles of a binder resin monomer obtained by emulsion polymerization, a colorant dispersion, a wax dispersion, etc. are prepared, and these are dispersed in an aqueous medium. By carrying out heating or the like, it undergoes an agglomeration step and an aging step. These are collected by washing and filtration, and dried to obtain toner mother particles. Further, if necessary, toner can be obtained by external addition or the like.

In the emulsion polymerization aggregation method, the aggregation is usually carried out in a tank equipped with a stirrer, but there are a heating method, a method of adding an electrolyte, and a method of combining them. When polymer primary particles are agglomerated with stirring to obtain particle aggregates of the desired size, the particle size of the particle aggregates is controlled based on the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by heating or adding an electrolyte. In the present invention, the electrolyte in the case of performing aggregation by adding an electrolyte may be either an organic salt or an inorganic salt. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) 3, Fe ₂ (SO ₄ ) ₃ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na and the like can be mentioned. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

In the present invention, the amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is preferably 0.05 parts by mass or more, and 0.1 parts by mass with respect to 100 parts by mass of the solid component of the mixed dispersion. Part or more is more preferable. Further, it is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. If the addition amount is too small, the progress of the agglutination reaction is delayed, and fine powders of 1 μm or less remain even after the agglomeration reaction, and the average particle size of the obtained particle aggregate may not reach the target particle size. On the other hand, if the amount is too large, rapid aggregation tends to occur and it is difficult to control the particle size, and the resulting aggregated particles may include problems such as inclusion of coarse powder or irregular shapes. When the aggregation is performed by adding an electrolyte, the aggregation temperature is 20 ° C. or higher, more preferably 30 ° C. or higher, and 70 ° C. or lower, more preferably 60 ° C. or lower.
The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is preferably (Tg-20) ° C. or higher, and more preferably (Tg-10) ° C. or higher, where Tg is the glass transition temperature of the polymer primary particles. . Moreover, Tg or less is preferable and (Tg-5) degree C or less is preferable.

  The time required for agglomeration is optimized depending on the shape of the apparatus and the processing scale, but in order for the toner particle size to reach the target particle size, it is usually held at the predetermined temperature for at least 30 minutes. desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.

  If necessary, particles having adhered or fixed resin particles may be formed on the surface of the particle aggregate after the above-described aggregation treatment. In some cases, the chargeability and heat resistance of the obtained toner can be improved by attaching or fixing the resin particles whose properties are controlled to the surface of the particle aggregate, and the effect of the present invention can be further enhanced. .

When resin particles having a glass transition temperature higher than that of the polymer primary particles are used as the resin particles, it is preferable because blocking resistance can be further improved without impairing fixing properties. The volume average particle size of the resin particles is preferably 0.02 μm or more, and more preferably 0.05 μm or more. Moreover, 3 micrometers or less, Furthermore, 1.5 micrometers or less are preferable. As the resin particles, those obtained by emulsion polymerization of monomers similar to the polymerizable monomers used for the above-mentioned polymer primary particles can be used.
Resin particles are usually used as a dispersion dispersed in water or a liquid mainly composed of water with a surfactant. However, when a charge control agent is added after the aggregation treatment, charge control is performed on the dispersion containing particle aggregates. It is preferable to add the resin particles after adding the agent.

In order to increase the stability of the particle aggregate obtained in the aggregation step, it is preferable to perform fusion in the aggregated particles in the aging step after the aggregation step. The temperature of the ripening step is preferably not less than Tg of the polymer primary particles, more preferably not less than 5 ° C higher than Tg, and preferably not more than 80 ° C higher than Tg, more preferably not less than 50 ° C higher than Tg. It is as follows. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature or higher of the polymer primary particles, it is usually held for 0.1 to 10 hours, preferably 1 to 6 hours. Is desirable.

  In addition, it is preferable to add a surfactant or raise the pH value after the aggregation process, preferably before the aging process or during the aging process. As the surfactant used here, one or more emulsifiers can be selected from the emulsifiers that can be used when producing the polymer primary particles. In particular, the emulsifiers used when producing the polymer primary particles. It is preferable to use the same. Although the addition amount in the case of adding surfactant is not limited, Preferably it is 0.1 mass part or more with respect to 100 mass parts of solid components of a mixed dispersion liquid, More preferably, it is 1 mass part or more, More preferably, it is 3 masses. It is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less. After the aggregation process, before the completion of the ripening process, by adding a surfactant or raising the pH value, it is possible to suppress aggregation of the particle aggregates aggregated in the aggregation process, In some cases, the generation of coarse particles can be suppressed.

  By heat treatment in the aging step, the polymer primary particles in the aggregate are fused and integrated, and the toner particle shape as the aggregate becomes close to a spherical shape. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner particles can be made nearly spherical. According to such an aging process, by controlling the temperature and time of the aging process, the shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, a spherical form with further fusion For example, various shapes of toner can be manufactured according to the purpose.

  The obtained particles are subjected to solid-liquid separation by a known method, the particles are collected, and washed and dried as necessary to obtain target toner mother particles.

<External addition process>
The toner of the present invention can be obtained by externally adding at least silica particles and inorganic particles to the surface of the toner base particles. However, as long as the effects of the present invention are not impaired, “others” The toner particles may be used in combination with or adhered to the surface of the toner base particles.

  Examples of the “other particles” include inorganic particles such as aluminum oxide (alumina), zinc oxide, tin oxide, barium titanate and strontium titanate; organic acid salt particles such as zinc stearate and calcium stearate; methacrylate ester Examples thereof include organic resin particles such as polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, and styrene-acrylic acid ester copolymer particles.

  The blending ratio of the silica particles, inorganic particles and “other particles” of the present invention is not particularly limited, and the amount of all external additives composed of the silica particles, inorganic particles and “other particles” is not particularly limited. However, the amount of all external additives used is preferably 1 part by mass or more, more preferably 1.2 parts by mass or more, and particularly preferably 1.3 parts by mass or more with respect to 100 parts by mass of the toner base particles. Moreover, 5 mass parts or less are preferable, 4.0 mass parts or less are more preferable, and 3.0 mass parts or less are especially preferable. If the amount used is too small, the fluidity may be deteriorated or the charge amount may not be controlled. On the other hand, if the amount used is too large, the free additive that has not adhered can contaminate the components in the cartridge. However, this may cause image defects.

  The order of attaching or fixing the inorganic particles used in the present invention to the surface of the toner base particles is not particularly limited. However, from the viewpoint of the working mechanism of the present invention, other combined external additives including silica particles are used. It is preferable to add them simultaneously or later.

  In the present invention, the method for adhering or fixing the silica particles, inorganic particles, and “other particles” on the surface of the toner base particles is not particularly limited, and a mixer generally used for toner production can be used. . Specifically, it is performed by uniformly stirring and mixing with a mixer such as a Henschel mixer, a V-type blender, a Redige mixer, or a Q-mixer.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”.

<Measurement method of average particle diameter of polymer primary particles>
Nikkiso Co., Ltd., Model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”), according to the instruction manual of NanoTrack, using its analysis software Microtrac Particle Analyzer Ver10.1.2.-019EE Using ion-exchanged water having a degree of 0.5 μS / cm as a dispersion medium, the measurement was performed by the method described in the instruction manual under the following conditions or by inputting the following conditions.

Solvent refractive index: 1.333
・ Measurement time: 100 seconds
・ Number of measurements: 1 time
-Particle refractive index: 1.59
・ Transparency: Transmission
・ Shape: Spherical shape
Density: 1.04

<Measurement method of weight average molecular weight Mw, peak molecular weight Mp>
It is measured by gel permeation chromatography (GPC) under the following conditions.
Apparatus: GPC apparatus HLC-8020 manufactured by Tosoh Corporation
Column: PL-gel Mixed-B 10 μ made by Polymer Laboratory
Reference column: TSKgel GMH manufactured by Tosoh Corporation
Solvent: THF
Sample concentration: 0.1% by weight
Calibration curve: Standard polystyrene

<Measurement method of volume median diameter (Dv50)>
Use Beckman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), use the company's Isoton II as the dispersion medium, and disperse so that the dispersoid concentration is 0.03% by mass. And measured. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv50) was used.

<Measurement method of circularity>
In the present invention, the “average circularity” is determined by dispersing toner base particles in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720 to 7140 particles / μL. (FPIA2100, manufactured by Toa Medical Electronics Co., Ltd.) is measured under the following apparatus conditions, and the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-HPF detection number: 2000-2500

The following is measured by the above device and automatically calculated and displayed in the above device, and “circularity” is defined by the following formula.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Method for measuring average primary particle size of silica particles and inorganic particles>
In the present invention, the “average primary particle size” of silica particles and inorganic particles is measured by image analysis of SEM photographs. In this example, using a scanning electron microscope S4500 manufactured by Hitachi, Ltd., after taking an appropriate number of photographs of the particles magnified 30000 times, 100 particles were randomly selected and image analysis made by Mitani Corporation. These equivalent circle diameters are measured by software WinROOF, and the average value is defined as “average primary particle diameter”.

<Measurement method of electrical resistance value>
For the measurement of the electrical resistance value in the present invention, an apparatus capable of measuring the resistivity of the powder under pressure is used. In this example, a powder resistance measurement system-PD51 type manufactured by Mitsubishi Chemical Corporation was used, and measurement was performed with a sample filling amount of 2.0 g and a weight of 4 kN.

<Measurement method of charge amount>
In the present invention, the charge amount of the inorganic particles is measured under the following conditions.
Carrier at temperature 23 ° C and humidity 55%: F-150 core (Powdertech) 19.8g
Inorganic particles: 0.2g
Is placed in a 20 ml glass bottle and left for 12 hours or longer. Thereafter, the mixture is mixed 50 times by hand shaking, and then stirred for 1 minute at an amplitude of 1.0 cm and a shaking speed of 500 rpm.
0.2 g is taken out from the glass bottle and measured with the blow-off TB-200 apparatus manufactured by Toshiba Chemical under the following settings.
N2 pressure gauge: 1.0Kg / cm2
SET TIME: 20.0sec
Wire mesh set on Faraday gauge (Stainless steel: 400 mesh)
The read Q value is calculated by the following calculation formula, and the average value of two times is defined as the charge amount.
Q / M (μ / g) = (Q (μC) / (sample weight (g)) × 100

Example 1
<Preparation of wax dispersion>
30 parts of pentaerythritol tetrastearyl ester (H476 manufactured by NOF Corporation), 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) (hereinafter abbreviated as “20% DBS aqueous solution”) 2.8 And 67.2 parts of demineralized water were heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.).

Subsequently, this dispersion was heated to 90 ° C. and homogenizer (manufactured by Gorin, 15-M-8).
(PA type) was used to start circulating emulsification under pressure of 25 MPa, and while measuring the particle diameter with Nanotrac, it was dispersed until the volume average diameter (Mv) reached 250 nm to prepare a wax dispersion.

<Preparation of polymer primary particle dispersion>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device was charged with 42.9 parts of the above wax dispersion and 336 parts of demineralized water, and a nitrogen stream The temperature was raised to 70 ° C., and 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once with stirring.

  After 5 minutes, the following mixture of monomers and emulsifier aqueous solution and the following initiator aqueous solution were added over 4.5 hours, and after the dropwise addition of the mixture of monomers and emulsifier aqueous solution, the temperature was raised to 90 ° C. over 30 minutes. Warm up. Furthermore, the following additional initiator aqueous solution was added over 3 hours, and the internal temperature was maintained at 90 ° C. for 1 hour with further stirring.

[Monomers]
Styrene 76.8 parts
Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Trichlorobromomethane 0.5 part Hexanediol diacrylate 1.0 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.3 parts

[Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 12.4 parts 8% L (+)-ascorbic acid aqueous solution 12.4 parts

[Additive initiator aqueous solution]
8% aqueous hydrogen peroxide solution 9.3 parts 8% L (+)-ascorbic acid aqueous solution 9.3 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion. The volume average diameter (Mv) of the polymer primary particles was 200 nm.

<Preparation of resin particle dispersion>
A reactor equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device was charged with 2.0 parts of a 20% DBS aqueous solution and 317 parts of demineralized water under a nitrogen stream. The temperature was raised to 90 ° C., and 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once while stirring.

  After 5 minutes, polymerization of a mixture of the following monomers and an aqueous emulsifier was initiated (from the time when 3.2 parts of an 8% aqueous hydrogen peroxide solution and 3.2 parts of an 8% L (+)-ascorbic acid aqueous solution were added all at once. After 5 minutes), the following initiator aqueous solution was added over 6 hours from the start of polymerization, and further maintained at 90 ° C. for 1 hour with stirring.

[Monomers]
Styrene 88.0 parts
Butyl acrylate 12.0 parts Acrylic acid 1.5 parts Trichlorobromomethane 0.5 parts Hexanediol diacrylate 0.4 parts

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.5 parts Demineralized water 66.4 parts

[Initiator aqueous solution]
8% aqueous hydrogen peroxide solution 18.9 parts 8% L (+)-ascorbic acid aqueous solution 18.9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white resin particle dispersion. The volume average diameter (Mv) of the resin particles was 115 nm.

<Preparation of colorant dispersion>
In a container equipped with a stirrer (propeller blade), carbon black (Mitsubishi Chemical Corporation, Mitsubishi Carbon Black MA100S) 20 parts, 20% DBS aqueous solution 1 part, nonionic surfactant (Kao Corporation, Emulgen 120) 4 parts, 75 parts of ion-exchanged water having an electric conductivity of 2 μS / cm was added and predispersed to obtain a premix solution. The volume average diameter (Mv) of carbon black in the premix solution was 90 μm.

  The premix solution was supplied to a wet bead mill and subjected to one-pass dispersion. The stator inner diameter was 75 mm, the separator diameter was 60 mm, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density of 6.0 g / cm 3) were used as a dispersion medium.

  The black colorant dispersion A is obtained by continuously supplying the premix slurry from a supply port at a supply speed of 50 L / hr by a non-pulsating metering pump and continuously discharging from the discharge port while keeping the rotation speed of the rotor constant. Got. The volume average diameter (Mv) of the colorant in the colorant dispersion was 150 nm.

<Manufacture of toner base particles>
Polymer primary particle dispersion Solid part 95 parts Resin particle dispersion Solid part 5 parts Colorant dispersion Colorant solid part 6 parts 20% DBS aqueous solution Solid part 0.1 part Using the above components, Toner mother particles were produced by the following procedure.

The polymer primary particle dispersion and 20% DBS aqueous solution were charged into a mixer equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and raw material / auxiliary charging device, and the internal temperature was 12 ° C. Mix evenly for 5 minutes. Subsequently, 0.52 parts of FeSO ₄ .7H ₂ O as a 5% aqueous solution of ferrous sulfate was added over 5 minutes at an internal temperature of 12 ° C. while continuing stirring, and then the colorant dispersion was added over 5 minutes. The mixture was uniformly mixed with the internal temperature kept at 12 ° C., and a 0.5% aluminum sulfate aqueous solution was added dropwise under the same conditions.

Thereafter, the temperature was raised to 50 ° C. over 30 minutes with stirring, and then raised to 51.5 ° C. over 90 minutes. Here, when the volume median diameter was measured using a multisizer, it was 7.2 μm. Thereafter, while stirring, the resin particle dispersion is added over 7 minutes and held for 60 minutes, 20% DBS aqueous solution is added over 10 minutes and then heated to 70 ° C. over 20 minutes. The temperature was raised to 90 ° C. over a period of minutes. Then, it heated up to 96 degreeC over 30 minutes.

  Then, the slurry obtained by cooling to 30 degreeC over 20 minutes was extracted, and it suction-filtered with the aspirator using the filter paper of 5 types C (Toyo Filter Paper Co., Ltd. No5C). The cake remaining on the filter paper is transferred to a stainless steel container equipped with a stirrer (propeller blade), added with 8 kg of ion exchange water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm, and then stirred for 30 minutes. I left it.

  After that, suction filtration is again performed with aspirator using filter paper of type 5 C (manufactured by Toyo Roshi Kaisha, Ltd., No. 5C), and the solid matter remaining on the filter paper is again provided with a stirrer (propeller blade) and has an electric conductivity. The sample was transferred to a 10 L container with 8 kg of 1 μS / cm ion exchange water, and uniformly dispersed by stirring at 50 rpm, and stirring was continued for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

  The cake obtained here was spread on a stainless steel pad so as to have a height of about 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner base particles A. Toner base particles A had a volume median diameter of 7.0 μm, an average circularity of 0.960, and a Dns of 4.1.

  Toner base particle B having a volume median diameter of 6.8 um, an average circularity of 0.980, and Dns of 3.3, a volume median diameter of 5.7 um, and an average circularity by the same formulation as toner base particle A Toner mother particles C having a toner particle size of 0.975 and Dns of 2.9, toner mother particles D having a volume median diameter of 7.0 μm, an average circularity of 0.950, and a Dns of 2.4.

<Manufacture of inorganic particles a >>
An aluminum hydrated oxide is added to an aqueous suspension of titanium dioxide particles (base material) having an average primary diameter of 0.30 um to coat the surface of the titanium dioxide particles. The coating treatment can be performed by neutralizing the water-soluble aluminum salt in the suspension. As the water-soluble aluminum salt, sodium aluminate was used. The coating amount was 6% as Al ₂ O _{3 with} respect to the weight of the titanium dioxide particles as the core. After adding the aluminum salt, it was neutralized at a pH of about 5 and aged for 30 minutes. Sodium hydroxide was used for the neutralization treatment. Then, it filtered and wash | cleaned, and also repulped and washed with water for the purpose of removing the electrolyte component contained in the cake which is solid content after filtration. The obtained cake was dried and pulverized to obtain inorganic particles a.

<Production of inorganic particles b>
In the production of inorganic particles a, an inorganic suspension was used except that an aqueous suspension of titanium dioxide particles having an average primary particle size of 0.25 um was used instead of an aqueous suspension of titanium dioxide particles (base material) having an average primary diameter of 0.30 um. Inorganic particles b were obtained in the same manner as in the production of the mother particles a.

<Production of inorganic particles c>
In the production of inorganic particles a, an inorganic suspension was used except that an aqueous suspension of titanium dioxide particles having an average primary particle size of 0.21 um was used instead of an aqueous suspension of titanium dioxide particles (base material) having an average primary diameter of 0.30 um. Inorganic particles c were obtained in the same manner as in the production of the mother particles a.

<Production of inorganic particles d>
Sodium silicate is added to an aqueous suspension of titanium dioxide particles (base material) having an average primary diameter of 0.25 μm to coat the surface of the titanium dioxide particles. The pH was adjusted to 9.0 or higher using sodium hydroxide, and 12% of SiO ₂ was added to the weight of the titanium dioxide particles as the core of the aqueous sodium silicate solution. After raising the temperature to 80 ° C., sulfuric acid was added and neutralized so that the pH became 6.5 over 180 minutes.
Subsequently, 6% was added as Al ₂ O _{3 with} respect to the weight of titanium dioxide particles having sodium aluminate as a core. After adding sodium aluminate, the mixture was neutralized at a pH of about 5 and aged for 30 minutes. Sodium hydroxide was used for the neutralization treatment. Then, it filtered and wash | cleaned, and also repulped and washed with water for the purpose of removing the electrolyte component contained in the cake which is solid content after filtration. The obtained cake was dried and pulverized to obtain inorganic particles d.

<Manufacture of inorganic particles e>
The untreated surface of titanium dioxide particles having an average primary diameter of 0.10 m was designated as inorganic particles e.

<Manufacture of inorganic particles h>
Disperse titanium dioxide particles with an average primary diameter of 0.08um in toluene, and after adding 16% octyltriethoxylane to the weight of the titanium dioxide particles , perform a powerful dispersion treatment so as not to coalesce, dry, By grinding, inorganic particles h were obtained.

<Manufacture of inorganic particles i>
In the production of inorganic particles d, 18% is added instead of 12% as SiO _{2 and 2} % is added instead of 6% as Al ₂ O _{3 in the} same manner as in the production of inorganic particles d. Thus, inorganic particles i were obtained.

<Production of inorganic particles j>
Aminopropyltriethoxysilane was diluted twice with pure water and stirred for 10 minutes for hydrolysis to prepare an aqueous solution of the hydrolysis product. The above-mentioned inorganic particles a are pulverized by a fluid energy pulverizer using water vapor heated to 250 ° C., and at that time, 0.3% trimethylolethane and amino group respectively based on the weight of titanium dioxide (inorganic particles a). An aqueous solution of a hydrolysis product corresponding to 2.0% as propyltriethoxysilane was added to a pulverizer, and these were coated to obtain inorganic particles j.

<Production of Toner E-1>
Into a 20 L Henschel mixer manufactured by Mitsui Mining Co., 100 parts (1500 g) of the toner mother particles A were added, and 1.6 parts of silica particles having an average primary particle diameter of 20 nm hydrophobized with silicone oil were added. The mixture was stirred and mixed at 3000 rpm for 10 minutes. Thereafter, inorganic particles a (charge amount: +49.9 uC / g, average primary particle diameter: 0.30 um, electric resistance value: 1.2 × 1
Toner E-1 was obtained by adding 0.05 part of 0 ⁸ Ω · cm) and further stirring and mixing at 3000 rpm for 5 minutes and sieving.

(Example 2)
<Production of Toner E-2>
In Example 1, instead of inorganic particles a, inorganic particles b (charge amount: +41.6 uC / g,
Toner E-2 was obtained in the same manner as in Example 1 except that 0.05 part of average primary particle size: 0.25 um, electric resistance: 1.7 × 10 ⁸ Ω · cm) was used.

(Example 3)
<Production of Toner E-3>
In Example 1, instead of inorganic particles a, inorganic particles c (charge amount: +10.6 uC / g,
Toner E-3 was obtained in the same manner as in Example 1 except that 0.05 part of average primary particle size: 0.21 um and electric resistance: 4.5 × 10 ⁹ Ω · cm) was used.

Example 4
<Production of Toner E-4>
In Example 1, instead of the inorganic particles a, inorganic particles d (charge amount: +6.7 uC / g, average primary particle size: 0.25 um, electric resistance: 5.3 × 10 ⁸ Ω · cm) are changed to 0. Toner E-4 was obtained in the same manner as in Example 1 except that 0.05 part was used.

(Example 5)
<Production of Toner E-5>
In Example 1, instead of the inorganic particles a, the inorganic particles e (charge amount: +1.7 uC / g, average primary particle diameter: 0.10 um, electric resistance: 4.1 × 10 ⁶ Ω · cm) are changed to 0. Toner E-5 was obtained in the same manner as in Example 1 except that 0.05 part was used.

(Example 6)
<Production of Toner E-6>
In Example 2, Toner E-6 was obtained in the same manner as in Example 2 except that toner base particle B was used instead of toner base particle A.

(Example 7)
<Production of Toner E-7>
In Example 2, Toner E-7 was obtained in the same manner as in Example 2 except that toner base particle C was used instead of toner base particle A.

(Comparative Example 1)
<Production of Toner C-1>
In Example 1, instead of the inorganic particles a, inorganic particles h (charge amount: +17.7 uC / g, average primary particle size: 0.08 um, electric resistance: 2.0 × 10 ¹⁰ Ω · cm) are changed to 0. Toner C-1 was obtained in the same manner as in Example 1 except that 0.05 part was used.

(Comparative Example 2)
<Production of Toner C-2>
In Example 1, 0.05 part of inorganic particles i (charge amount: -4.6 uC / g, average primary particle size: 0.25 um, 9.3 × 10 ⁷ Ω · cm) instead of inorganic particles a Toner C-2 was obtained in the same manner as in Example 1 except that it was used.

(Comparative Example 3)
<Production of Toner C-3>
In Example 1, instead of inorganic particles a, inorganic particles j (charge amount: +117 uC / g, average primary particle size: 0.3 um, electric resistance: 1.5 × 10 ¹³ Ω · cm) were changed to 0.05. Toner C-3 was obtained in the same manner as in Example 1 except that a part of the toner was used.

(Comparative Example 4)
<Production of Toner C-4>
In Example 2, a toner C-4 was obtained in the same manner as in Example 2 except that the amount of the inorganic particles b added was 0.01 part.

(Comparative Example 5)
<Production of Toner C-5>
In Example 2, a toner C-5 was obtained in the same manner as in Example 2 except that the amount of the inorganic particles b added was 0.3 part.

(Comparative Example 6)
<Production of Toner C-6>
In Example 2, Toner C-6 was obtained in the same manner as in Example 2 except that toner base particle C was used instead of toner base particle A.

<Evaluation>
Using the toner obtained as described above, a process speed of 50 mm / second, a drum φ24 mm non-magnetic one-component method, a developing roller, a charging blade, an organic electrophotographic photosensitive drum that is contact-charged by a charging roller, a belt transfer, A full-color printer equipped with a fixing machine using a thermal fixing system was used to print 2000 sheets of a 5% printing rate chart continuously, then image quality ([1] paper fog on printed matter, [2] organic photoreceptor drum) The presence or absence of image defects due to contamination of the upper charging roller, [3] presence or absence of image defects due to filming on the photosensitive drum, and [4] toner scattering around the developing tank unit) were evaluated. The evaluation results are shown in Table 1.

<Paper cover on printed matter>
Paper fog was evaluated as follows. In other words, Nippon Denshoku SE-6000 (standard light / viewing angle): C / 2, with UV cut filter (420nm) attached) Was calculated. The paper cover was an average of three sheets.
Δ = delta Wb
Judgment criteria are as follows.
◎: Paper fog less than 1.0 ○: Paper fog 1.0 or more, less than 1.5 ×: Paper fog 1.5 or more

<Image defect due to contamination of charging roller on organic photoconductor drum>
<Presence or absence of image defects due to filming on the photosensitive drum>
The presence / absence of image defects due to contamination of the charging roller on the organic photosensitive drum and the presence / absence of image defects due to filming on the photosensitive drum were visually determined based on the presence / absence of the image defects. Judgment criteria are as follows.
◎: No image defects
○: There is no image defect, but there are signs (image defect may occur if printing is continued as it is)
×: Image defect is recognized

<Toner scattering around development tank unit>
Toner scattering around the developing tank unit was judged by visual evaluation of the toner scattering level around the developing tank unit and presence / absence of printed matter stains. Judgment criteria are as follows.
◎: There is almost no toner scattering by visual evaluation, and there is no stain on the printed matter. ○: Some toner scattering is observed by visual evaluation, but there is no contamination on the printed matter. Dirt is recognized

As is apparent from the results shown in Table 1, the toner of the present invention is a good toner that has no fogging during printing durability and little toner scattering (Examples 1 to 7). On the other hand, when the average primary particle diameter of the inorganic particles was smaller than 0.1 μm (Comparative Example 1), the fog deterioration in the latter half of the printing durability was observed. This is presumably because the inorganic particles have a small particle size, so that they roll on the surface of the mother particle due to stress due to printing, and are embedded and fixed in the mother particle simultaneously with desorption. Further, when the chargeability of the inorganic particles was negative (Comparative Example 2), a sufficient carrier effect was not obtained, and good fogging performance was not seen.
When the electrical resistance value of the inorganic particles is larger than 1 × 10 ¹⁰ Ω · cm (Comparative Example 3), the inorganic particles that contaminate the roller for charging the organic photoreceptor drum to the organic photoreceptor drum of this roller are not limited. As a result, the organic photoreceptor could not obtain an appropriate charge, resulting in an image defect on the printed matter.
When the addition ratio of silica particles (a) / inorganic particles (b) is large (Comparative Example 4), excessive silica particles are present around the inorganic particles, so that the effect of the present invention by the inorganic particles is weakened. In the latter half of the printing durability, the fog deterioration was recognized. When the average circularity of the mother particles was small (Comparative Example 6), the fog maintenance in the latter half of the printing durability was insufficient. This is because the inorganic particles fall into the “dents” of the mother particles due to printing durability (= because they are large external additives, they move on the surface of the mother particles due to stress and fall into the “dents” that are not subjected to stress). Is thought to have occurred because of the inability to act effectively.

(Example 8)
<Production of Toner E-8>
In Example 2, simultaneously with inorganic particles, compound (II) (average primary particle size 0.5 um) was added to 0.0%.
Toner E-8 was obtained in the same manner as in Example 2 except that 5 parts were added.
Compound (I): Mg _0.5 Zn _0.17 Al _0.33 (OH) ₂ (CO ₃ ) _0.165 · 0.45H ₂ O powder treated with fatty acid (treatment amount 3 parts)

Example 9
<Production of Toner E-9>
In Example 2, zinc stearate (average primary particle size: 1 um) was added to the inorganic particles at the same time.
Toner E-9 was obtained in the same manner as in Example 2 except that 03 parts were added.

(Example 10)
<Production of Toner E-10>
In Example 2, simultaneously with inorganic particles, Compound (I) (average primary particle size 0.5 um) was added to 0.0%.
Toner E-10 was obtained in the same manner as in Example 2 except that 5 parts and 0.03 part of zinc stearate (average primary particle size: 1 um) were added.
Compound (I): Mg _0.5 Zn _0.17 Al _0.33 (OH) ₂ (CO ₃ ) _0.165 · 0.45H ₂ O powder treated with fatty acid (treatment amount 3 parts)

<Evaluation>
Evaluation was performed using a printer in the same manner as in Examples 1 to 7 except that the toner obtained as described above was used and the process speed was 130 mm / sec.

Claims (6)

A negatively chargeable toner containing at least silica particles and titanium oxide particles,
The ratio a / b between the addition amount (a) of the silica particles and the addition amount (b) of the titanium oxide particles is 10 or more and 100 or less,
And the average circularity of the negatively chargeable toner is 0.955 or more and 0.985 or less,
The electrostatic image developing toner is characterized in that the titanium oxide particles satisfy the following (1) to (3).
(1) Average primary particle size is 0.1 μm or more (2) Electric resistance value is 1 × 10 ⁺¹⁰ Ω · cm or less (3) Positive chargeability 2. The electrostatic image developing toner according to claim 1, wherein the addition amount of the titanium oxide particles is 0.3 parts by mass or less with respect to 100 parts by mass of the toner base particles. The electrostatic image developing toner according to claim 1, wherein the titanium oxide particles are subjected to a surface treatment. The electrostatic charge image developing toner according to claim 1, wherein the toner has a volume median diameter of 4 μm or more and 8 μm or less. 5. The electrostatic image developing toner according to claim 1, further comprising an organic acid metal salt. 6. The toner for developing an electrostatic charge image according to claim 1, comprising a compound represented by the following general formula (4).
M1 y1 · M2 y2 · M3 x · (OH) 2 · Ax / n · mH 2 O ···· (4)
(Wherein M1 represents at least one divalent metal selected from the group consisting of Mg, Ca, Sr and Ba, and M2 represents a divalent metal selected from the group consisting of Zn, Cd, Pb and Sn. At least one species, M3 represents a trivalent metal, A represents an n-valent anion, and x, y1, y2 and m represent 0 <x ≦ 0.5, y1 + y2 = 1-x, An integer satisfying the relational expression of 0 ≦ m <2 is indicated, and the surface treatment is performed with higher fatty acids.)