JP5748016B2 - Positively chargeable toner for electrostatic image development - Google Patents

Description

  The present invention is a positively chargeable toner for electrostatic image development (hereinafter, simply referred to as “toner”) used for developing an electrostatic latent image in electrophotography, electrostatic recording method, electrostatic printing method and the like. Yes.)

  In an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and an electrostatic printing apparatus, a desired image is formed by developing an electrostatic latent image formed on a photoreceptor with toner for developing an electrostatic image. This technique is widely used. Such a technique is applied to a copying machine, a printer, a facsimile machine, and a multifunction machine of these.

  For example, an electrophotographic apparatus using an electrophotographic method generally forms the electrostatic latent image on the photoreceptor after the surface of the photoreceptor made of a photoconductive material is uniformly charged by various means. . Next, the electrostatic latent image is developed using toner, the toner image is transferred onto a recording material such as paper, and then fixed by heating or the like to obtain a copy.

The toner used for development includes a negatively chargeable toner and a positively chargeable toner. Positively chargeable toners are preferably used in recent years because they suppress the generation of ozone and provide good chargeability.
Further, on the surface of toner particles used for development, in order to improve the charging stability, fluidity, durability and the like of the toner, inorganic fine particles and organic fine particles generally having a smaller particle diameter than colored resin particles (toner particles). External additives such as these are externally added (attached).

  In a toner using a conventional external additive, in the process of continuous printing of a large number of sheets, the external additive may be caused by mechanical stress in the developing device (increased number of contact between toner particles due to stirring or the like). The toner particles are buried inside and / or released (desorbed) from the surface of the toner particles. For this reason, the function of the external additive is lowered, and it becomes difficult to impart to the toner particles a stable charging property (charging stability) over time.

  In addition, the toner particles embedded with the external additive cause a phenomenon (filming phenomenon) in which the toner particles adhere to the surface of the photoreceptor, and image quality is likely to be deteriorated due to fogging or the like. The external additive released (desorbed) from the surface of the toner particles deteriorates the charging characteristics of the surface of the photoreceptor, and causes the printing durability and image quality of the toner to deteriorate. Especially under high temperature and high humidity conditions, the image quality is significantly deteriorated by filming.

Therefore, even when the number of contact between the toner particles by stirring or the like increases in the developing device as in the case of continuous printing of a large number of sheets, problems such as embedding and / or releasing of the external additive do not occur. There is a demand for a toner that maintains a state in which an external additive is suitably attached over time and maintains a stable chargeability (charging stability).
Patent Documents 1 and 2 disclose toners obtained by adding fatty acid zinc particles to toner particles and externally treating them.

Japanese Patent Laid-Open No. 9-236942 JP 2010-8454 A

However, Patent Document 1 mentions printing characteristics in a high-temperature and high-humidity environment, but does not disclose at all whether filming can be prevented in a high-temperature and high-humidity environment.
On the other hand, Patent Document 2 discloses a filming evaluation result for a toner containing fatty acid zinc particles. As shown in Table 5 in the document, the toner disclosed in Patent Document 2 cannot completely prevent filming in a high temperature and high humidity environment.

  The object of the present invention is that filming on the photoconductor is unlikely to occur, the toner particles are provided with a stable chargeability over time, and even when a large number of continuous printing is performed, image quality deterioration due to fog or the like hardly occurs. In particular, it is an object of the present invention to provide a toner for developing an electrostatic charge image that hardly deteriorates in image quality even in a high temperature and high humidity environment (HH environment).

  The inventor has intensively studied to achieve the above object, and as a result, filming on the photoconductor hardly occurs by using specific amounts of fatty acid zinc particles and silica fine particles each having a specific particle size as external additives. In addition, even when a large number of continuous prints are given to toner particles with a stable charging property over time, image quality is hardly deteriorated due to fog or the like, and particularly in a high temperature and high humidity environment (HH environment). Has been found to be difficult to occur, and the present invention has been completed.

  That is, the positively chargeable toner for developing an electrostatic charge image of the present invention is a positively chargeable toner for developing an electrostatic charge image containing a binder resin, a colored resin particle containing a colorant and a positive charge control agent, and an external additive. The external additive includes fatty acid zinc particles having a number average primary particle size of 0.5 to 1.5 μm, silica fine particles (A) having a number average primary particle size of 5 to 20 nm, and a number average primary particle size. Containing silica fine particles (B) of 25 to 80 nm, the content of the external additive is 0.01 to 0.5 parts by mass of the fatty acid zinc particles with respect to 100 parts by mass of the colored resin particles, The silica fine particles (A) are 0.05 to 3 parts by mass, the silica fine particles (B) are 0.05 to 3 parts by mass, and the water adsorption amount of the fatty acid zinc particles is the fatty acid zinc particles. 0.1 to 1% by mass relative to the mass of And features.

  With the above configuration, in the present invention, high chargeability can be maintained even in a high temperature and high humidity environment, and filming on the photoreceptor can be prevented.

  In the present invention, the balance between the storage stability and the fixing performance of the toner is good, and it can withstand fluctuations in the storage environment and use environment of the toner. As a result, it is excellent in high temperature storage stability and in a high temperature and high humidity environment. From the viewpoint of obtaining a toner having excellent printing durability, the positive charge control agent is preferably a positive charge control resin having a glass transition temperature of 70 to 100 ° C.

  In the present invention, the content of the external additive is 0.02 to 0.15 parts by mass of the fatty acid zinc particles and 100 parts by mass of the silica fine particles (A) with respect to 100 parts by mass of the colored resin particles. It is preferably 2 to 1 part by mass, and the silica fine particles (B) are preferably 0.2 to 3 parts by mass.

  In the present invention, the colored resin particles may be produced by a wet method.

  According to the toner for developing an electrostatic charge image of the present invention as described above, filming on the photoconductor hardly occurs, the toner particles are provided with a stable charging property over time, and even when continuous printing of a large number of sheets is performed, Provided is a toner for developing an electrostatic charge image that hardly causes deterioration in image quality due to fog or the like, and that hardly deteriorates in image quality even in a high temperature and high humidity environment (HH environment).

  The electrostatic charge image developing toner of the present invention is a positively chargeable toner for developing an electrostatic charge image containing a colored resin particle containing a binder resin, a colorant and a positive charge control agent, and an external additive. Are fatty acid zinc particles having a number average primary particle size of 0.5 to 1.5 μm, silica fine particles (A) having a number average primary particle size of 5 to 20 nm, and a number average primary particle size of 25 to 80 nm. Silica fine particles (B) are contained, and the content of the external additive is 0.01 to 0.5 parts by mass of the fatty acid zinc particles with respect to 100 parts by mass of the colored resin particles. ) Is 0.05 to 3 parts by mass, and the silica fine particles (B) are 0.05 to 3 parts by mass, and the water adsorption amount of the fatty acid zinc particles is based on the mass of the fatty acid zinc particles. 0.1 to 1% by mass.

Hereinafter, the toner for developing an electrostatic charge image of the present invention (hereinafter sometimes simply referred to as “toner”) will be described.
In the toner of the present invention, an external additive containing a predetermined amount of fatty acid zinc particles and silica fine particles having a predetermined particle diameter is adhered and added (external addition) to colored resin particles containing a binder resin, a colorant, and a charge control agent. Is obtained.
Hereinafter, the manufacturing method of the colored resin particles used in the present invention, the colored resin particles obtained by the manufacturing method, the manufacturing method of the toner of the present invention using the colored resin particles, and the toner of the present invention will be described in order.

1. Production method of colored resin particles Generally, the production method of colored resin particles is roughly classified into dry methods such as a pulverization method, and wet methods such as an emulsion polymerization aggregation method, a suspension polymerization method, and a dissolution suspension method. The wet method is preferable because it is easy to obtain a toner excellent in printing characteristics such as the property. Among wet methods, a polymerization method such as an emulsion polymerization aggregation method and a suspension polymerization method is preferable because a toner having a relatively small particle size distribution on the order of microns is preferable. A suspension polymerization method is more preferable among polymerization methods. preferable.

  In the emulsion polymerization aggregation method, an emulsified polymerizable monomer is polymerized to obtain a resin fine particle emulsion, which is aggregated with a colorant dispersion or the like to produce colored resin particles. Further, the dissolution suspension method described above forms droplets of a solution in which a toner component such as a binder resin or a colorant is dissolved or dispersed in an organic solvent in an aqueous medium, and removes the organic solvent to form colored resin particles. It is a manufacturing method and can use a well-known method, respectively.

  The colored resin particles of the present invention can be produced by employing a wet method or a dry method. Among the wet methods, a preferred suspension polymerization method is adopted, and the following process is performed.

(A) Suspension polymerization method (A-1) Preparation step of polymerizable monomer composition First, a polymerizable monomer, a colorant, a charge control agent, a release agent added as necessary, and the like These other additives are mixed to prepare a polymerizable monomer composition. The mixing at the time of preparing the polymerizable monomer composition is performed using, for example, a media type dispersing machine.

  In the present invention, the polymerizable monomer means a monomer having a polymerizable functional group, and the polymerizable monomer is polymerized to become a binder resin. It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyl toluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl and dimethylaminoethyl acrylate; methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and dimethylaminoethyl methacrylate; acrylonitrile And nitrile compounds such as methacrylonitrile; amide compounds such as acrylamide and methacrylamide; and olefins such as ethylene, propylene, and butylene. These monovinyl monomers can be used alone or in combination of two or more. Of these, styrene, styrene derivatives, and acrylic acid or methacrylic acid derivatives are preferably used as monovinyl monomers.

In order to improve hot offset and storage stability, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer. A crosslinkable polymerizable monomer means a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; alcohols having two or more hydroxyl groups such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; Examples include ester compounds in which two or more carboxylic acids are ester-bonded; other divinyl compounds such as N, N-divinylaniline and divinyl ether; compounds having three or more vinyl groups. These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
In the present invention, the crosslinkable polymerizable monomer is usually used at a ratio of 0.1 to 5 parts by mass, preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the monovinyl monomer. desirable.

  Furthermore, it is preferable to use a macromonomer as a part of the polymerizable monomer because the balance between the storage stability of the obtained toner and the fixing property at low temperature is improved. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain, and is a reactive oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. The macromonomer is preferably one that gives a polymer having a higher Tg than the Tg of the polymer obtained by polymerizing the monovinyl monomer. The macromonomer is preferably used in an amount of 0.03 to 5 parts by mass, more preferably 0.05 to 1 part by mass, with respect to 100 parts by mass of the monovinyl monomer.

In the present invention, a colorant is used. However, when producing a color toner, black, cyan, yellow, and magenta colorants can be used.
As the black colorant, carbon black, titanium black, magnetic powder such as iron zinc oxide and nickel iron oxide can be used.

  As the cyan colorant, for example, a copper phthalocyanine compound, a derivative thereof, and an anthraquinone compound can be used. Specifically, C.I. I. Pigment blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, 60, and the like.

  Examples of the yellow colorant include monoazo pigments, azo pigments such as disazo pigments, and compounds such as condensed polycyclic pigments. I. Pigment yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, and 186.

  As the magenta colorant, monoazo pigments, azo pigments such as disazo pigments, and compounds such as condensed polycyclic pigments are used. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 237, 251, 269 and C.I. I. Pigment violet 19 and the like.

  In the present invention, each colorant can be used alone or in combination of two or more. The amount of the colorant is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

As the charge control agent, it is preferable to use a charge control resin because it has high compatibility with the binder resin (or polymerizable monomer) and can impart stable chargeability to the toner particles. The charge control resin is a polar group-containing copolymer having a glass transition temperature (Tg) of 70 to 100 ° C., preferably 75 to 100 ° C., more preferably 75 to 95 ° C. in a differential scanning calorimeter (DSC). It is desirable to be. When the glass transition temperature (Tg) is in the above range, the toner has a good balance between the storage stability and the fixability and can withstand fluctuations in the storage environment and use environment of the toner. In addition, a toner having excellent printing durability even in a high temperature and high humidity environment can be obtained. When the glass transition temperature (Tg) is less than 70 ° C., the storage stability of the toner is lowered, and the toner printing performance may be adversely affected. Conversely, when the Tg exceeds 100 ° C., the toner In some cases, the fixability of the toner may deteriorate and the toner printing performance may be adversely affected.
Examples of the polar group include a quaternary ammonium base and a sulfonic acid group. The charge control resin is roughly classified into a positive charge positive charge control resin and a negative charge negative charge control resin depending on the type of the polar group. Since a positively chargeable toner that generates less harmful substances such as ozone when obtaining an electrostatic charge image is obtained, a positive charge control resin is used.

A copolymer containing a quaternary ammonium base as a polar group, which is preferable as a positive charge control resin, is a copolymer including a repeating structural unit having a quaternary ammonium base, as represented by the following formula (1). It is more preferable.
As the repeating structural unit constituting the quaternary ammonium base-containing copolymer, in addition to the repeating structural unit having a quaternary ammonium base represented by the following formula (1), a vinyl monomer unit, and (meth) It is particularly preferred to contain acrylate monomer units.

(In said formula (1), R < ¹ > is a hydrogen atom or a methyl group, R < ² > is a C1-C3 alkylene group, R < ³ > -R < ⁵ > is respectively independently C1-C1. 6 is an alkyl group, a phenyl group, or an aralkyl group having 1 to 12 carbon atoms, and X is a halogen atom, an alkylsulfonic acid residue having 1 to 6 carbon atoms, a benzenesulfonic acid residue, or a paratoluenesulfonic acid residue. .)

  When the total amount of the quaternary ammonium base-containing copolymer is 100% by mass, the content ratio of the repeating structural unit having a quaternary ammonium base is preferably 0.05 to 12% by mass, and 0.1 to 10%. More preferably, it is mass%. When it exists in the said range, it becomes easy to control the charge amount of a quaternary ammonium base containing copolymer.

The quaternary ammonium base-containing copolymer can be produced, for example, by the following method.
1. A method obtained by copolymerizing a vinyl monomer and a quaternary ammonium base-containing (meth) acrylate monomer.
2.1. A method obtained by reacting the copolymer obtained in step 1 with paratoluenesulfonic acid or methanesulfonic acid.
3. A method obtained by quaternizing a nitrogen atom of a dialkylaminoalkyl group in a copolymer obtained by copolymerizing a vinyl monomer and a dialkylaminoalkyl (meth) acrylate monomer with a quaternizing agent. .

  Specific examples of the quaternary ammonium base-containing (meth) acrylate monomer include N, N, N-trimethyl-N- (2-methacryloxyethyl) ammonium chloride (DMC: dimethylaminoethylmethyl methacrylate methacrylate), N -Benzyl-N, N-dimethyl-N- (2-methacryloxyethyl) ammonium chloride (DML: dimethylaminoethylbenzyl chloride methacrylate) and the like. These monomers can be used alone or in combination of two or more.

  Examples of the dialkylaminoalkyl (meth) acrylate monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylmethylaminoethyl (meth) acrylate, and dibutylaminoethyl (meth) acrylate. These monomers can be used alone or in combination of two or more.

  As quaternizing agents, halogenated organic compounds such as methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, benzyl chloride, benzyl bromide; methyl sulfonic acid alkyl ester, ethyl sulfonic acid alkyl ester, propyl sulfonic acid alkyl ester, benzene And sulfonic acid alkyl esters such as sulfonic acid alkyl ester and paratoluenesulfonic acid alkyl ester. These can be used alone or in combination of two or more.

As the vinyl monomer, the vinyl aromatic hydrocarbon monomer and (meth) acrylate monomer described in the polymerizable monomer described above are preferably used.
Specific examples of the vinyl aromatic hydrocarbon monomer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene. 2-propylstyrene, 3-propylstyrene, 4-propylstyrene, 2-isopropylstyrene, 3-isopropylstyrene, 4-isopropylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2-methyl- α-methylstyrene, 3-methyl-α-methylstyrene, 4-methyl-α-methylstyrene, 2-ethyl-α-methylstyrene, 3-ethyl-α-methylstyrene, 4-ethyl-α-methylstyrene, 2-propyl-α-methylstyrene, 3-propyl-α-methylstyrene, 4-propyl- -Methylstyrene, 2-isopropyl-α-methylstyrene, 3-isopropyl-α-methylstyrene, 4-isopropyl-α-methylstyrene, 2-chloro-α-methylstyrene, 3-chloro-α-methylstyrene, 4 -Chloro-α-methylstyrene, 2,3-dimethylstyrene, 3,4-dimethylstyrene, 2,4-dimethylstyrene, 2,6-dimethylstyrene, 2,3-diethylstyrene, 3,4-diethylstyrene, 2,4-diethylstyrene, 2,6-diethylstyrene, 2-methyl-3-ethylstyrene, 2-methyl-4-ethylstyrene, 2-chloro-4-methylstyrene, 2,3-dimethyl-α-methyl Styrene, 3,4-dimethyl-α-methylstyrene, 2,4-dimethylstyrene, 2,6-dimethyl-α-methylstyrene, 2,3-diethyl-α-methylstyrene, 3,4-diethyl-α-methylstyrene, 2,4-diethyl-α-methylstyrene, 2,6-diethyl-α-methylstyrene, 2-ethyl-3- Examples include methyl-α-methylstyrene, 2-methyl-4-propyl-α-methylstyrene, and 2-chloro-4-ethyl-α-methylstyrene. These monomers can be used alone or in combination of two or more.

  Specific examples of the (meth) acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, acrylic Acrylic acid esters such as acid n-hexyl, 2-ethylhexyl acrylate, hydroxypropyl acrylate, lauryl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid Methacrylic acid esters such as isobutyl, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, hydroxypropyl methacrylate, lauryl methacrylate; No grade ammonium salt (meth) acrylate compound (simply referred to. (Meth) acrylate compounds) it includes. These monomers can be used alone or in combination of two or more.

  In the present invention, when a vinyl aromatic hydrocarbon monomer unit and a (meth) acrylate monomer unit are included as a repeating structural unit constituting the quaternary ammonium base-containing copolymer, the copolymerization ratio (mass ratio) Is preferably 70:30 to 90:10, more preferably 75:25 to 88:12. When it exists in the said range, it becomes easy to obtain the quaternary ammonium base containing copolymer which has Tg mentioned above.

  Various commercial products can be used as the quaternary ammonium base-containing copolymer. Examples of commercially available products include FCA-592P (: trade name, manufactured by Fujikura Kasei Co., Ltd., Tg: 82 ° C., weight average molecular weight (Mw): 12,000).

The weight average molecular weight (Mw) of the quaternary ammonium base-containing copolymer is preferably 2,000 to 50,000, more preferably 4,000 to 40,000, and even more preferably. Is preferably 6,000 to 35,000.
When the mass average molecular weight (Mw) of the quaternary ammonium base-containing copolymer is in the above range, the quaternary ammonium base-containing copolymer can be suitably dispersed in the polymerizable monomer composition. And a toner having a stable charge amount with time can be obtained. When the weight average molecular weight (Mw) of the quaternary ammonium base-containing copolymer is less than 2,000, storage stability and printing durability may be deteriorated. On the other hand, when the mass average molecular weight (Mw) of the quaternary ammonium base-containing copolymer is 50,000, the fixability may be lowered.

The charge control agent is desirably used in a proportion of usually 0.01 to 10 parts by mass, preferably 0.03 to 8 parts by mass with respect to 100 parts by mass of the monovinyl monomer.
When the addition amount of the charge control agent is in the above range, fog is small, transferability is excellent, and printing durability can be effectively enhanced. When the addition amount of the charge control agent is less than 0.01 parts by mass with respect to 100 parts by mass of the monovinyl monomer, the amount of charge imparted to the toner particles becomes insufficient, which adversely affects the toner printing performance. There is a risk. On the other hand, when the addition amount of the charge control agent exceeds 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer, the charge amount becomes too high and the printing performance may be deteriorated.

  It is preferable to use a molecular weight modifier as another additive. Examples of molecular weight modifiers include t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and mercaptan compounds such as 2,2,4,6,6-pentamethylheptane-4-thiol; tetramethylthiuram monosulfide, Tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipentamethylenethiuram tetrasulfide, N, N′-dimethyl-N, N′-diphenylthiuram disulfide, N, N′-dioctadecyl-N, N′- Thiuram compounds such as diisopropyl thiuram disulfide; pentamethylene dithiocarbamic acid piperidine salt, pipecolyl dithiocarbamic acid pipecoline salt, sodium dimethyldithiocarbamate, diethyldithiocarbamic acid Thorium, sodium dibutyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, N- ethyl -N- phenyl dithiocarbamate, zinc, dithiocarbamic acid compounds tellurium diethyldithiocarbamate and the like; and the like. Of these molecular weight regulators, mercaptan compounds and thiuram compounds are preferred. These can be used alone or in combination of two or more.

  The addition amount of the molecular weight modifier is usually 0.05 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the monovinyl monomer. Part. The molecular weight modifier is added before the polymerization starts or during the polymerization.

Moreover, it is preferable to add a mold release agent as another additive. By adding a release agent, the releasability of the toner from the fixing roll during fixing can be improved. Any releasing agent can be used without particular limitation as long as it is generally used as a releasing agent for toner. For example, low molecular weight polyolefin wax and modified wax thereof; plant natural wax such as jojoba; petroleum wax such as paraffin; mineral wax such as ozokerite; synthetic wax such as Fischer-Tropsch wax; polyhydric alcohol such as dipentaerythritol ester Ester; etc. are mentioned. A polyhydric alcohol ester is preferred because it can balance the storage stability and low-temperature fixability of the toner. These may be used alone or in combination of two or more.
The release agent is preferably used in an amount of 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

(A-2) Suspension step for obtaining a suspension (droplet formation step)
In the present invention, the polymerizable monomer composition obtained as described above is dispersed in an aqueous medium containing a dispersion stabilizer, a polymerization initiator is added, and then the polymerizable monomer composition liquid is added. Perform drop formation. The method for forming droplets is not particularly limited. For example, an (in-line type) emulsifying disperser (trade name “Milder” manufactured by Ebara Manufacturing Co., Ltd.), a high-speed emulsifying disperser (trade name “T. K. Homomixer MARK Type II ") or the like capable of strong stirring.

  As a polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate: 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methyl-N- (2- Hydroxyethyl) propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2-′azobis (2,4-dimethylvaleronitrile), and 2,2′-azobisisobutyro Azo compounds such as nitrile; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, And organic peroxides such as di-t-butylperoxyisophthalate and t-butylperoxyisobutyrate. That. These can be used alone or in combination of two or more. Among these, it is preferable to use an organic peroxide because residual polymerizable monomers can be reduced and printing durability is excellent.

  Among organic peroxides, peroxyesters are preferred because the initiator efficiency is good and the remaining polymerizable monomer can be reduced, and non-aromatic peroxyesters, that is, peroxyesters having no aromatic ring. Esters are more preferred.

  As described above, the polymerization initiator may be added before the droplet formation after the polymerizable monomer composition is dispersed in the aqueous medium. However, the polymerization initiator is not dispersed in the aqueous medium. It may be added to the monomer composition.

  The addition amount of the polymerization initiator used for the polymerization of the polymerizable monomer composition is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 100 parts by mass of the monovinyl monomer. It is -15 mass parts, Most preferably, it is 1-10 mass parts.

  In the present invention, the aqueous medium refers to a medium containing water as a main component.

  In the present invention, the aqueous medium preferably contains a dispersion stabilizer. Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metals such as aluminum oxide and titanium oxide. Oxides; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; inorganic compounds such as; water-soluble polymers such as polyvinyl alcohol, methylcellulose, and gelatin; anionic surfactants; Organic compounds such as nonionic surfactants; amphoteric surfactants; The said dispersion stabilizer can be used 1 type or in combination of 2 or more types.

  Among the above dispersion stabilizers, inorganic compounds, particularly colloids of poorly water-soluble metal hydroxides are preferred. By using a colloid of an inorganic compound, particularly a poorly water-soluble metal hydroxide, the particle size distribution of the colored resin particles can be narrowed, and the residual amount of the dispersion stabilizer after washing can be reduced. The polymerized toner can reproduce an image clearly and does not deteriorate environmental stability.

(A-3) Polymerization step As in (A-2) above, droplet formation is performed, the resulting aqueous dispersion medium is heated to initiate polymerization, and an aqueous dispersion of colored resin particles is formed.
The polymerization temperature of the polymerizable monomer composition is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

  The colored resin particles may be used as a polymerized toner as they are or with an external additive added, but the colored resin particles are used as a core layer, and are obtained by making a shell layer different from the core layer on the outside. It is preferable to use so-called core-shell type (or “capsule type”) colored resin particles. The core-shell type colored resin particles balance the reduction of the fixing temperature and the prevention of aggregation during storage by coating the core layer made of a material having a low softening point with a material having a higher softening point. be able to.

  There is no restriction | limiting in particular as a method of manufacturing a core shell type colored resin particle using the said colored resin particle mentioned above, It can manufacture by a conventionally well-known method. An in situ polymerization method and a phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by in situ polymerization will be described below.
Addition of a polymerizable monomer (polymerizable monomer for shell) and a polymerization initiator to form a shell layer into an aqueous medium in which colored resin particles are dispersed, and then polymerize to form a core-shell type color. Resin particles can be obtained.

  As the polymerizable monomer for the shell, the same monomers as the aforementioned polymerizable monomers can be used. Among them, it is preferable to use monomers such as styrene, acrylonitrile, and methyl methacrylate, which can obtain a polymer having a Tg exceeding 80 ° C., alone or in combination of two or more.

  As a polymerization initiator used for polymerization of the polymerizable monomer for shell, persulfate metal salts such as potassium persulfate and ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) Water-soluble such as azo initiators such as) propionamide) and 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); A polymerization initiator can be mentioned. These can be used alone or in combination of two or more. The amount of the polymerization initiator is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer for shell.

  The polymerization temperature of the shell layer is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

(A-4) Washing, filtration, dehydration, and drying steps The aqueous dispersion of colored resin particles obtained by the polymerization is subjected to filtration, removal of the dispersion stabilizer, and dehydration according to a conventional method after completion of the polymerization. The drying operation is preferably repeated several times as necessary.

  As the above washing method, when an inorganic compound is used as the dispersion stabilizer, the dispersion stabilizer can be dissolved in water and removed by adding an acid or alkali to the aqueous dispersion of colored resin particles. preferable. When a colloid of a poorly water-soluble inorganic hydroxide is used as the dispersion stabilizer, it is preferable to adjust the pH of the colored resin particle aqueous dispersion to 6.5 or less by adding an acid. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as formic acid and acetic acid can be used. Particularly, since the removal efficiency is large and the burden on the manufacturing equipment is small, Sulfuric acid is preferred.

  Various known methods can be used for the method of dehydration and filtration, and there is no particular limitation. Examples thereof include a centrifugal filtration method, a vacuum filtration method, and a pressure filtration method. Also, the drying method is not particularly limited, and various methods can be used.

(B) Pulverization method When the pulverization method is used to produce colored resin particles, the following process is performed.
First, a binder resin, a colorant, a charge control agent, and other additives such as a release agent added as necessary are mixed in a mixer such as a ball mill, a V-type mixer, a Henschel mixer (trade name). ), Mix using a high-speed dissolver, internal mixer, etc. Next, the mixture obtained as described above is kneaded while being heated using a pressure kneader, a twin-screw extrusion kneader, a roller or the like. The obtained kneaded material is coarsely pulverized using a pulverizer such as a hammer mill, a cutter mill, or a roller mill. Furthermore, after finely pulverizing using a pulverizer such as a jet mill or a high-speed rotary pulverizer, it is classified into a desired particle size by a classifier such as an air classifier or an airflow classifier, and colored resin particles obtained by a pulverization method. Get.

  In addition, other additives such as a binder resin, a colorant, and a charge control agent used in the pulverization method, and a release agent added as necessary, are those mentioned in the above (A) suspension polymerization method. Can be used. Further, the colored resin particles obtained by the pulverization method can be made into core-shell type colored resin particles by a method such as an in situ polymerization method in the same manner as the colored resin particles obtained by the suspension polymerization method (A) described above.

  As the binder resin, other resins that have been widely used for toners can be used. Specific examples of the binder resin used in the pulverization method include polystyrene, styrene-butyl acrylate copolymer, polyester resin, and epoxy resin.

2. Colored resin particles Colored resin particles are obtained by a production method such as the above-described (A) suspension polymerization method or (B) pulverization method.
Hereinafter, the colored resin particles constituting the toner will be described. The colored resin particles described below include both core-shell type and non-core type.

  The volume average particle diameter (Dv) of the colored resin particles is preferably 3 to 15 μm, more preferably 4 to 12 μm. When Dv is less than 3 μm, the fluidity of the polymerized toner is lowered, transferability may be deteriorated, and the print density may be lowered. When Dv exceeds 15 μm, the resolution of the image may decrease.

  The colored resin particles have a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of preferably 1.0 to 1.3, more preferably 1. 0-1.2. If Dv / Dn exceeds 1.3, transferability, image density, and resolution may decrease. The volume average particle diameter and the number average particle diameter of the colored resin particles can be measured using, for example, a particle size analyzer (trade name “Multisizer” manufactured by Beckman Coulter).

From the viewpoint of image reproducibility, the average circularity of the colored resin particles of the present invention is preferably 0.96 to 1.00, more preferably 0.97 to 1.00, and 0.98 to 1 More preferably, it is 0.00.
When the average circularity of the colored resin particles is less than 0.96, the fine line reproducibility of printing may be deteriorated.

  In the present invention, the circularity is defined as a value obtained by dividing the circumference of a circle having the same projected area as the particle image by the projected image of the particle. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the particles, and is an index indicating the degree of unevenness of the colored resin particles. The average circularity is determined by the colored resin particles. 1 is shown in the case of a perfect sphere, and the value becomes smaller as the surface shape of the colored resin particles becomes more complicated.

3. Production method of toner of the present invention The toner of the present invention is prepared by mixing and stirring the colored resin particles together with the external additive defined in the present invention, and suitably adding and adding the external additive to the surface of the colored resin particles (external To obtain).

  A method for adding (externally adding) the external additive defined in the present invention to the surface of the colored resin particles is not particularly limited. For example, an FM mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super Using a device capable of mixing and stirring, such as a mixer (trade name, manufactured by Kawada Seisakusho), Q mixer (: trade name, manufactured by Mitsui Mining), a mechano-fusion system (: trade name, manufactured by Hosokawa Micron) be able to.

The external additive of the present invention comprises fatty acid zinc particles having a number average primary particle size of 0.5 to 1.5 μm, silica fine particles (A) having a number average primary particle size of 5 to 20 nm, and a number average primary particle size of 25 to 25. Contains 80 nm silica fine particles (B).
The number average primary particle size of the fatty acid zinc particles is preferably 0.7 to 1.2 μm, and more preferably 0.8 to 1.0 μm. When the number average primary particle size of the fatty acid zinc particles is within the above range, filming on the photoconductor is unlikely to occur. Thus, it is possible to obtain a toner that hardly deteriorates in image quality due to fog or the like, and that hardly deteriorates in image quality even in a high temperature and high humidity environment (HH environment).

The fatty acid (R—COOH) corresponding to the fatty acid moiety (R—COO ⁻ ) of the fatty acid zinc particles used in the present invention is a chain formula among carboxylic acids (R—COOH) having one carboxyl group (—COOH). Includes everything with a structure. In the present invention, the fatty acid moiety is preferably derived from a higher fatty acid having a large number of carbon atoms in the alkyl group (R-).

Examples of higher fatty acids include lauric acid (CH ₃ (CH ₂ ) ₁₀ COOH), tridecanoic acid (CH ₃ (CH ₂ ) ₁₁ COOH), myristic acid (CH ₃ (CH ₂ ) ₁₂ COOH), pentadecanoic acid (CH ₃ ). (CH ₂ ) ₁₃ COOH), palmitic acid (CH ₃ (CH ₂ ) ₁₄ COOH), heptadecanoic acid (CH ₃ (CH ₂ ) ₁₅ COOH), stearic acid (CH ₃ (CH ₂ ) ₁₆ COOH), arachidic acid ( CH ₃ (CH ₂ ) ₁₈ COOH), behenic acid (CH ₃ (CH ₂ ) ₂₀ COOH), lignoceric acid (CH ₃ (CH ₂ ) ₂₂ COOH) and the like. The number of carbon atoms in the alkyl group of the fatty acid is preferably 12-24, more preferably 14-22, and still more preferably 16-20. Although the fatty acid which comprises these fatty acid zinc particles can be used individually or in combination of 2 or more types, respectively, it is preferable to use independently from the point of obtaining a uniform characteristic.

The fatty acid zinc particles used in the present invention are preferably plate-shaped. If it is plate-like, it will be difficult to drop off from the colored resin particles, and stable chargeability over time can be imparted.
The fatty acid zinc particles can be used alone or in combination of two or more.

The number average primary particle size of the silica fine particles (A) is 5 to 20 nm, preferably 6 to 18 nm, and more preferably 7 to 14 nm. The silica fine particles (A) are preferably fumed silica.
When the number average primary particle diameter of the silica fine particles (A) is less than 5 nm, the silica fine particles are easily embedded from the surface to the inside of the colored resin particles, and sufficient fluidity is imparted to the toner particles. Cannot be performed, and printing performance may be adversely affected. On the other hand, when the number average primary particle size of the silica fine particles (A) exceeds 20 nm, the proportion (coverage) of the silica fine particles with respect to the surface of the toner particles is reduced, so that the fluidity is improved. May not be sufficiently imparted to the ink and may adversely affect printing performance.

The number average primary particle size of the silica fine particles (B) is 25 to 80 nm, preferably 30 to 70 nm, and more preferably 35 to 60 nm.
When the number average primary particle size of the silica fine particles (B) is less than 25 nm, the spacer effect is lowered, and the silica fine particles are easily embedded from the surface of the colored resin particles, and the flow is suitable over time. In some cases, the toner particles cannot be imparted with toner properties, and the printing performance may be adversely affected. On the other hand, when the number average primary particle diameter of the silica fine particles (B) exceeds 80 nm, the silica fine particles are easily released from the surface of the toner particles, the function as an external additive is lowered, and the printing performance is reduced. May have adverse effects.

In the external additive used in the present invention, the content of fatty acid zinc particles is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the colored resin particles, and the content of silica fine particles (A) is It is 0.05-3 mass parts, and content of a silica fine particle (B) is 0.05-3 mass parts.
The content of the fatty acid zinc particles is preferably 0.02 to 0.15 parts by mass and more preferably 0.05 to 0.15 parts by mass with respect to 100 parts by mass of the colored resin particles.
The content of the silica fine particles (A) is preferably 0.1 to 2 parts by mass and more preferably 0.2 to 1 part by mass with respect to 100 parts by mass of the colored resin particles.
The content of the silica fine particles (B) is preferably 0.2 to 3 parts by mass and more preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the colored resin particles.

When the content of the fatty acid zinc particles is within the above range, filming on the photoconductor hardly occurs, the toner particles are given stable charging properties over time, and even when continuous printing of a large number of sheets is performed, fogging, etc. Therefore, it is possible to obtain a toner in which the image quality is hardly deteriorated by the toner, and the image quality is hardly deteriorated even in a high temperature and high humidity environment (HH environment).
When the content of the fatty acid zinc particles is less than 0.01 parts by mass, the function as a desired external additive may not be obtained, and the printing durability may be deteriorated. On the other hand, when the content of the fatty acid zinc particles exceeds 0.5 parts by mass, the printing durability may be deteriorated due to a decrease in the toner charge amount.
When the content of the silica fine particles (A) is less than 0.05 parts by mass, the function as an external additive cannot be sufficiently exhibited, and the printing performance may be adversely affected. On the other hand, when the content of the silica fine particles (A) exceeds 3 parts by mass, the silica fine particles are easily released from the surface of the toner particles, the function as an external additive is lowered, and the printing performance is adversely affected. There is.
When the content of the silica fine particles (B) is less than 0.05 parts by mass, the function as an external additive cannot be sufficiently exhibited, and the printing performance may be adversely affected. On the other hand, when the content of the silica fine particles (B) exceeds 3 parts by mass, the silica fine particles are easily released from the surface of the toner particles, the function as an external additive is deteriorated, and the printing performance is adversely affected. There is.

  Various commercially available products can be used as the fatty acid zinc particles, and examples thereof include MZ-2 manufactured by NOF Corporation (: trade name, number average primary particle size: 0.8 to 1.2 μm).

  As the silica fine particles (A), various commercially available products can be used. For example, HDK2150 (: trade name, number average primary particle size: 12 nm) manufactured by Clariant, R504 (: trade name, manufactured by Nippon Aerosil Co., Ltd.) Number average primary particle size: 12 nm), RA200HS (: trade name, number average primary particle size: 12 nm); MSP-012 (: trade name, number average primary particle size: 16 nm), MSP-013 (: Product name, number average primary particle size: 12 nm), TG820F manufactured by Cabot Corporation (: product name, number average primary particle size: 7 nm); and the like.

  Various commercially available products can be used as the silica fine particles (B). For example, NA50Y (: trade name, number average primary particle size: 35 nm), VPNA50H (: trade name, number average primary particle) manufactured by Nippon Aerosil Co., Ltd. MSP-011 (trade name, number average primary particle size: 30 nm); H05TA (: trade name, number average primary particle size: 50 nm) manufactured by Clariant, and the like.

The moisture adsorption amount of the fatty acid zinc particles is 0.1 to 1% by mass with respect to the mass of the fatty acid zinc particles. Here, “0.1 to 1% by mass with respect to the mass of the fatty acid zinc particles” means that when the predetermined mass of the fatty acid zinc particles is 100% by mass, 0.1 to 0.1% in the predetermined mass. It means 1% by mass. When the water adsorption amount of the fatty acid zinc particles exceeds the above range, there is a possibility that the chargeability is lowered or filming on the photoreceptor is caused.
The moisture adsorption amount of the fatty acid zinc particles is more preferably 0.1 to 0.5% by mass, and further preferably 0.2 to 0.4% by mass with respect to the mass of the fatty acid zinc particles. The moisture adsorption amount can be measured by an adsorption / desorption measurement device, a continuous vapor adsorption device, or the like.

The silica fine particles (A) and the silica fine particles (B) used as external additives in the present invention are preferably hydrophobized. As the hydrophobizing agent, for example, a silane coupling agent, silicone oil, or the like can be used.
Examples of the silane coupling agent include disilazane such as hexamethyldisilazane; cyclic silazane; trimethylsilane; trimethylchlorosilane; dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, and methyltrimethoxysilane. , Methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxy Alkylsilane compounds such as silane, γ-methacryloxypropyltrimethoxysilane, and vinyltriacetoxysilane, and γ- Aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (2 -Aminoethyl) 3-aminopropyltrimethoxysilane, and aminosilane compounds such as N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane; These can be used alone or in combination of two or more.
Examples of the silicone oil include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, and amino-modified silicone oil. These can be used alone or in combination of two or more.
Among the above, the hydrophobizing agent may be contained alone or in combination of two or more, and when a silane coupling agent or silicone oil is used, the resulting toner is more preferable because it provides high image quality. .

As a method for hydrophobizing the fatty acid zinc particles used as an external additive in the present invention, a general method can be used, and examples thereof include a wet method and a dry method.
Specifically, while stirring the fatty acid zinc particles used as an external additive at high speed, the hydrophobic treatment agent is dropped or sprayed (dry method), and the hydrophobic treatment agent is dissolved in an organic solvent, Examples include a method (wet method) of adding fatty acid zinc particles while stirring an organic solvent containing a chemical treatment agent.

4). Toner according to the present invention The toner according to the present invention obtained through the above-described steps is prepared by adding an external additive containing specific amounts of fatty acid zinc particles having a specific particle size, silica fine particles (A) and silica fine particles (B). As a result, filming on the photoconductor is unlikely to occur, and even if a stable chargeability is provided to the toner particles over time, and continuous printing of a large number of sheets is performed, image quality deterioration due to fog or the like is unlikely to occur. In particular, the toner hardly deteriorates in image quality even in a high temperature and high humidity environment (HH environment).

  Specific embodiments of the present invention will be described below in more detail with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist. Parts and% are based on mass unless otherwise specified.

1. Preparation of fatty acid zinc particles (Fatty acid zinc particles A)
Commercially available zinc stearate particles (manufactured by NOF Corporation, product name “MZ-2”) were prepared by air classification to obtain fatty acid zinc particles A.

(Fatty acid zinc particles B)
Commercially available zinc stearate particles (manufactured by NOF Corporation, product name “MZ-2”) were prepared by air classification to obtain fatty acid zinc particles B.

(Fatty acid zinc particles C)
Commercially available zinc stearate particles (manufactured by Sakai Chemical Industry Co., Ltd., product name “SPZ-100F”) were used as fatty acid zinc particles C as they were.

2. Evaluation of fatty acid metal salt particles Fatty acid zinc particles A to C, magnesium stearate particles (manufactured by Sakai Chemical Industry, trade name “SPX-100F”), and calcium stearate particles (manufactured by Sakai Chemical Industry, trade name “SPC-100F”) ), The number average primary particle diameter and the amount of moisture adsorption were measured.

2-1. Number average primary particle size of fatty acid metal salt particles About 0.1 g of a measurement sample (fatty acid metal salt particles) is weighed and taken in a beaker, and an alkylbenzenesulfonic acid aqueous solution (trade name “Drywell”, manufactured by Fuji Film) as a dispersant. 0.1 mL was added. Isoton II is further added to the beaker, and after 60 W for 1 minute dispersion with an ultrasonic disperser, using a laser diffraction particle size distribution analyzer (SALD-2100, manufactured by Shimadzu Corporation), the medium: Isoton II It was measured.

2-2. Water Adsorption Amount of Fatty Acid Metal Salt Particles The water adsorption amount was measured by the following method using an IGAsorb Moisture Sorption Analyzer (manufactured by HIDEN ANALYTICA).
A sample jig is set in the pre-dried chamber, and about 20 mg of fatty acid metal salt particles are precisely weighed. Under a predetermined temperature, the inside of the chamber was set to a relative humidity of 0.7% or less. Thereafter, the mass of the fatty acid metal salt particles when the mass fluctuation rate of the fatty acid metal salt particles was constantly within ± 0.3% was defined as W1. Thereafter, the temperature was not changed, and the sample was allowed to stand for 10 minutes or more under a target relative humidity. The fatty acid metal salt particle mass W2 when the moisture was adsorbed on the surface of the fatty acid metal salt particle and the mass was stabilized again was measured. And the amount of adsorbed moisture was calculated | required with the following formula.
<Calculation formula>
Adsorbed water content (mass%) = 100 × (W2-W1-W3) / W1
(W3 represents the value of the amount of adsorbed moisture of the sample jig under the measurement environment (temperature, humidity) in the above calculation formula.)

  Table 1 shows the measurement results of the number average primary particle size and water adsorption amount of each fatty acid metal salt particle together with the shape of the fatty acid metal salt particle.

3. Production of toner (Example 1)
Polymerizable monomer comprising 76 parts of styrene and 24 parts of n-butyl acrylate (calculation of the resulting copolymer Tg = 60 ° C.) and carbon black as a colorant (trade name “# 25B” manufactured by Mitsubishi Chemical Corporation) 7 parts, charge control agent (styrene / acrylic resin (containing 2 mass% of quaternary ammonium base-containing (meth) acrylate monomer unit), manufactured by Fujikura Kasei Co., Ltd., trade name “FCA-592P”, Tg: 82 ° C. 1.2 parts of Mw: 12,000), 0.5 part of divinylbenzene as a crosslinkable polymerizable monomer, 0.75 part of tetraethylthiuram disulfide as a molecular weight regulator, and polymethacrylate macromonomer (Toa Gosei Chemical) 0.25 part of Kogyo Co., Ltd., trade name “AA-6”, Tg: 94 ° C.) was stirred with a stirrer, and then uniformly dispersed with a media type dispersing machine. 5 parts of fatty acid ester wax (manufactured by NOF Corporation, trade name “Nissan Electol WEP-7”) was added, mixed, and dissolved as a release agent to obtain a polymerizable monomer composition. All the preparations of the polymerizable monomer composition were performed at 25 ° C.

  On the other hand, at 25 ° C., an aqueous solution obtained by dissolving 10.2 parts of magnesium chloride (water-soluble polyvalent metal salt) in 250 parts of ion-exchanged water, and sodium hydroxide (alkali metal hydroxide) 6.2 in 50 parts of ion-exchanged water. The aqueous solution in which the part was dissolved was gradually added with stirring to prepare a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion.

  The polymerizable monomer composition is added to the magnesium hydroxide colloidal dispersion obtained as described above, stirred, and t-butylperoxy-2-ethylhexanoate (NOF Corporation) as a polymerization initiator. (Product name “Perbutyl O”) 4.4 parts, and then added for 10 minutes at 15,000 rpm using an in-line type emulsifying disperser (trade name “Ebara Milder” manufactured by Ebara Seisakusho Co., Ltd.). The droplets of the polymerizable monomer composition were formed by shearing and stirring.

  Next, an aqueous dispersion of the polymerizable monomer composition formed into droplets was added from the top of the reactor. The temperature was raised to 90 ° C. to carry out the polymerization reaction. A water-soluble initiator dissolved in 1 part of methyl methacrylate and 10 parts of ion-exchanged water as a polymerizable monomer for the shell while maintaining the temperature in the reactor at 90 ° C. when the polymerization addition rate reaches 95% As a mixture, 0.1 part of 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide) was added. Further, the temperature was maintained at 90 ° C. for 3 hours, and the polymerization was continued. Then, the reaction was stopped by cooling with water to obtain a slurry of colored resin particles.

Water is added to the aqueous dispersion of the colored resin particles obtained by adding sulfuric acid to pH 6.5 or lower, acid-washing, dehydrating by filtration, and then adding 500 parts of ion-exchanged water again to re-slurry. Washing was performed. Thereafter, similarly, dehydration and washing with water were repeated three times, and after dehydration by filtration, the mixture was placed in a drier container and dried at 45 ° C. for 48 hours to obtain dried colored resin particles.
The obtained colored resin particles had a volume average particle size (Dv) of 9.0 μm and a particle size distribution (Dv / Dn) of 1.14.

  With respect to 100 parts of the colored resin particles obtained as described above, 0.1 parts of fatty acid zinc particles A obtained as described above were used as an external additive, and commercially available hydrophobized treatment was carried out using other external additives. Silica fine particles (A) (manufactured by Cabot, trade name “TG820F”, number average primary particle size: 7 nm) 0.6 parts, commercially available hydrophobized silica fine particles (B) (manufactured by Nippon Aerosil Co., Ltd., trade name) Add 1.0 part of “NA50Y”, number average primary particle size: 35 nm, and mix for 5 minutes at a peripheral speed of 30 m / s using a high-speed stirrer (trade name “Henschel Mixer” manufactured by Mitsui Mining Co., Ltd.). Externally added, a positively chargeable toner for developing a non-magnetic one-component electrostatic image of Example 1 was prepared and used for the test.

(Example 2)
A toner of Example 2 was produced in the same manner as in Example 1 except that the amount of fatty acid zinc particles A was changed from 0.1 part to 0.2 part, and was subjected to the test.

(Example 3)
A toner of Example 3 was produced in the same manner as in Example 1 except that the amount of fatty acid zinc particles A was changed from 0.1 part to 0.3 part, and was subjected to the test.

Example 4
A toner of Example 4 was produced in the same manner as in Example 1 except that 0.1 part of fatty acid zinc particles A was changed to 0.1 part of fatty acid zinc particles B, and was subjected to the test.

  (Comparative example 1) Fatty acid zinc particle A 0.1 part is made into a magnesium stearate particle (The Sakai Chemical Industry make, brand name "SPX-100F", number average primary particle size: 0.71 micrometer, moisture adsorption amount: 2.61. (Mass%) A toner of Comparative Example 1 was produced in the same manner as in Example 1 except that the content was changed to 0.1 part, and was subjected to the test.

(Comparative Example 2)
Fatty acid zinc particles A 0.1 part, calcium stearate particles (manufactured by Sakai Chemical Industry, trade name “SPC-100F”, number average primary particle size: 0.51 μm, moisture adsorption amount: 2.09 mass%) 0.1 A toner of Comparative Example 2 was produced in the same manner as in Example 1 except that it was changed to the part, and was subjected to the test.

(Comparative Example 3)
A toner of Comparative Example 3 was produced in the same manner as in Example 1 except that 0.1 part of fatty acid zinc particles A was changed to 0.1 part of fatty acid zinc particles C, and was subjected to the test.

(Comparative Example 4)
A toner of Comparative Example 4 was produced in the same manner as in Example 1 except that the silica fine particles (B) were not used, and subjected to the test.

4). Toner Printing Test A printing test was performed on the toners of Examples 1 to 4 and Comparative Examples 1 to 4. As the printing test, a printing durability test and a photoconductor durability test in a high temperature and high humidity (HH) environment were performed.

4-1. Print durability test (Number of fog generation under normal temperature and humidity (NN) environment, Number of fog generation under high temperature and high humidity (HH) environment)
Put the toner in a commercially available non-magnetic one-component development type printer (trade name “HL-2140” manufactured by Brother Kogyo Co., Ltd., printing speed: 21 sheets / minute of A4 paper), and an environment (temperature 23 ° C., humidity 50%) In the same NN environment, continuous printing was performed at a print density of 1%, and fogging was measured every 500 sheets. The number of sheets with fog of 1% or more was defined as the number of NN environment fog generation. Printing durability was performed up to 5,000 sheets, and when the fog became 1% or more on the way, printing durability was stopped at that time. In the test results, 5,000 <indicates that the fog is less than 1% even when 5,000 sheets are continuously printed.

The fog was measured as follows.
First, white solid printing is performed, and the printer is stopped in the middle, and the toner in the non-image area on the developed photoreceptor is treated with an adhesive tape (trade name “Scotch Mending Tape 810-3- manufactured by Sumitomo 3M Limited”). 18 "), and affixed to new printing paper. The color tone was measured with a spectral color difference meter (Nippon Denshoku Co., Ltd., device name “SE-2000”) for the portion where the toner in the non-image area was adhered. Similarly, an unused adhesive tape is attached to the printing paper as a reference, and the color tone is measured in the same manner. Each color tone is expressed as coordinates in the L ^* a ^* b ^* space, and the color tone of the measurement sample and the reference sample is used. The fog value was obtained by calculating the color difference ΔE. Smaller fog values indicate less fog and better image quality.
A similar printing durability test was also performed in an environment (HH environment) at a temperature of 32 ° C. and a humidity of 80% to obtain the number of HH environment fog generation. Printing durability was performed up to 2,500 sheets, and when the fog became 1% or more during the printing, printing durability was stopped at that time. In the test results, 2,500 <indicates that the fog is less than 1% even when 2,500 sheets are continuously printed.

4-2. Photoconductor durability test under high temperature and high humidity (HH) environment
Put the toner in a commercially available non-magnetic one-component development type printer (trade name “HL-2140” manufactured by Brother Kogyo Co., Ltd., printing speed: 21 sheets / min. Of A4 paper) and an environment with a temperature of 32 ° C. and a humidity of 80% ( (HH environment). Thereafter, a printing test was performed at a printing density of 4% under the same HH environment. When the remaining amount of toner ran out during the test, the toner cartridge was replaced as needed, and the printing test was continued up to 12,000 sheets. Half-tone printing (printing density 50%) was printed for every 1,000 printed sheets, and the number of sheets that became a white and blurred image as a whole was determined as the number of photoconductor filming occurrences. As the number of photoconductor filming increases, it indicates that the external additive filming on the photoconductor is less and good image quality can be maintained. In the test results, 12,000 <indicates that even if 12,000 sheets were printed continuously, the image did not become white and blurred.

  Table 2 shows the print test results of the toners of Examples 1 to 4 and Comparative Examples 1 to 4 together with the toner composition. In Table 2, “silica A” indicates silica fine particles (A), and “silica B” indicates silica fine particles (B).

5. Summary of Toner Evaluation First, the toners of Comparative Example 1 and Comparative Example 2 are examined. In the toners of Comparative Examples 1 and 2, the durability test result of the photoreceptor in a high temperature and high humidity (HH) environment was 4,000 sheets or 5,000 sheets, respectively. Therefore, it can be seen that the toners of Comparative Example 1 and Comparative Example 2 that do not contain fatty acid zinc particles but contain fatty acid magnesium particles or fatty acid calcium particles are likely to cause photoconductor filming in a high-temperature and high-humidity (HH) environment. As can be seen from Tables 1 and 2, the fatty acid magnesium particles and the fatty acid calcium particles have a higher amount of adsorbed moisture than the fatty acid zinc particles. Therefore, it is suggested that a fatty acid salt having a high amount of adsorbed water causes photoconductor filming.
Next, the toner of Comparative Example 3 will be examined. In the toner of Comparative Example 3, the durability test result of the photoreceptor in a high temperature and high humidity (HH) environment was 9,000 sheets. Therefore, it can be seen that the toner containing fatty acid zinc particles having a number average primary particle size of less than 0.5 μm is likely to cause photoconductor filming in a high temperature and high humidity (HH) environment.
Subsequently, the toner of Comparative Example 4 will be examined. The toner of Comparative Example 4 has a fog generation number of 2,500 in a normal temperature and normal humidity (NN) environment, and a fog generation number of 1,000 in a high temperature and high humidity (HH) environment. The durability test result of the photoreceptor in the (HH) environment was 2,000. As can be seen from Table 2, the durability in the normal temperature and normal humidity (NN) environment and the high temperature and high humidity (HH) environment, and the durability of the photoconductor in the high temperature and high humidity (HH) environment are described in Example 1. The toner of Comparative Example 4 was the most inferior among the toners of To 4 and Comparative Examples 1 to 4. Therefore, the binary toner containing fatty acid zinc particles and one kind of silica fine particles is more normal temperature and normal humidity (NN) than the ternary toner containing fatty acid zinc particles and two kinds of silica fine particles having different particle diameters. It can be seen that fog is likely to occur in an environment and a high temperature and high humidity (HH) environment, and that photoconductor filming is likely to occur in a high temperature and high humidity (HH) environment.

In contrast to Comparative Examples 1 to 4, the toners of Examples 1 to 4 have a fog generation number of 3,000 or more in a normal temperature and normal humidity (NN) environment and a fog generation number in a high temperature and high humidity (HH) environment. The result of the durability test of the photosensitive member in a high-temperature and high-humidity (HH) environment exceeding 2,000 sheets exceeded 12,000 sheets. Therefore, in the toners of Examples 1 to 4 using the external additive defined in the present invention, fogging hardly occurs in both a normal temperature and normal humidity (NN) environment and a high temperature and high humidity (HH) environment, and It can be seen that the toner hardly causes photoconductor filming in a high temperature and high humidity (HH) environment.
The toners of Examples 1, 2 and 4 in which the content of fatty acid zinc particles is 0.2 parts by mass or less have a fog generation number of 5,000 in a room temperature and normal humidity (NN) environment. The result exceeded. Further, in the toners of Examples 1 and 4 in which the content of fatty acid zinc particles is 0.1 parts by mass, the number of fog occurrences in a high temperature and high humidity (HH) environment exceeds 2,500. It was.

Claims (4)

In a positively chargeable toner for developing an electrostatic image containing a binder resin, a colorant particle containing a colorant and a positive charge control agent, and an external additive,
The external additive is
Fatty acid zinc particles having a number average primary particle size of 0.5 to 1.5 μm, silica fine particles (A) having a number average primary particle size of 5 to 20 nm, and silica fine particles having a number average primary particle size of 25 to 80 nm Containing (B),
The content of the external additive is 0.01 to 0.5 parts by mass of the fatty acid zinc particles and 0.05 to 3 parts by mass of the silica fine particles (A) with respect to 100 parts by mass of the colored resin particles. And the silica fine particles (B) are 0.05 to 3 parts by mass,
The positively chargeable toner for developing an electrostatic image, wherein the water adsorption amount of the fatty acid zinc particles is 0.1 to 1% by mass with respect to the mass of the fatty acid zinc particles. The positively chargeable toner for developing an electrostatic charge image according to claim 1, wherein the positive charge control agent is a positive charge control resin .   The content of the external additive is 0.02 to 0.15 parts by mass of the fatty acid zinc particles and 0.2 to 1 parts by mass of the silica fine particles (A) with respect to 100 parts by mass of the colored resin particles. The positively chargeable toner for developing electrostatic images according to claim 1, wherein the silica fine particles (B) are 0.2 to 3 parts by mass.   The positively chargeable toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein the colored resin particles are produced by a wet method.