JP4779830B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image that can be used for developing an apparatus using electrophotography such as a copying machine, a facsimile machine, and a printer.

  In general, in electrophotography, a print image is formed by the following process in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus. First, an electrostatic latent image is formed on the photoreceptor. Next, the electrostatic latent image is developed with toner on the developing roll to form a toner image, and the formed toner image is transferred onto various transfer materials such as paper as necessary. The transferred toner image is fixed by heating, pressurizing, solvent vapor, or the like to form a printed image.

In recent years, there has been a growing need for colorization of image forming apparatuses such as copying machines, facsimiles, and printers that use electrophotography. In color printing, high-definition images such as photographs are also printed. Therefore, a high resolution is required, and a color toner that can cope with this is demanded. In addition, for these, reduction in printing cost is also demanded. Therefore, in toner, it is required that printing quality does not deteriorate even when a large number of sheets are printed, that is, excellent printing durability is required. . Furthermore, recently, it has been demanded that the image quality is maintained and the printing durability is not deteriorated even when used in a high temperature and high humidity environment.
In response to the above requirements, conventionally, attempts have been made to improve resolution and printing durability by adding (externally adding) inorganic fine particles or organic fine particles having a smaller particle diameter to colored resin particles to form a toner. Has been made.

  Patent Document 1 discloses a toner obtained by externally adding 2 to 6 μm colored resin particles with silica fine particles having an average particle diameter of 5 nm or more and less than 20 nm and titanium dioxide fine particles having an average particle diameter of 20 nm or more and 40 nm or less. However, this toner has improved transferability, developability, and cleaning properties, particularly in the initial stage of the durability test.However, when a durability test of a large number of sheets is performed, due to the deterioration of the toner such as burying of external additives, The fluidity of the toner is lowered and fogging is likely to occur.

Patent Document 2 discloses a toner containing kaolin clay (kaolinite) whose surface is modified by a silane coupling agent to be hydrophobized as an external additive.
Furthermore, Patent Document 3 discloses a toner containing calcined kaolin clay as an external additive. However, when kaolin clay is fired, crystal water is lost and the layered structure is lost.

  However, although the toners disclosed in Patent Document 2 and Patent Document 3 are improved to some extent in printing durability, they are not sufficient for recently required levels, and the charge amount during durability in a high temperature and high humidity environment is particularly insufficient. There is a problem that fog is likely to occur.

Japanese Patent Laid-Open No. 3-100161 JP 54-28630 A JP-A-5-158276

  An object of the present invention is to provide a toner for developing an electrostatic charge image that has excellent printing durability and does not cause fogging not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment.

  As a result of intensive studies to achieve this object, the present inventor achieved the above object by including inorganic layered clay compound fine particles in which specific ions are intercalated between layers as an external additive. Based on this finding, the present invention has been completed.

Thus, according to the present invention, a binder resin, colored resin particles comprising a charge control agent and a colorant, and a toner for developing an electrostatic image containing an external additive,
(I) The external additive is 0.1 to 0.5 part by weight of a fine particle of an inorganic layered clay compound having a number average primary particle size of 0.3 to 0.7 μm with respect to 100 parts by weight of the colored resin particles, the number average. 0.1 to 3 parts by weight of the fine particles (A) having a primary particle diameter of 5 to 15 nm with respect to 100 parts by weight of the colored resin particles, and 100 parts by weight of fine particles (B) having a number average primary particle diameter of 20 to 200 nm. 0.1-3 parts by weight having free to parts, and fine particles (a) and fine particles (B) are fine particles of silica or titania independently, and (ii) inorganic layered clay compound An electrostatic charge image developing toner is provided which is a smectite group in which quaternary ammonium ions are intercalated between layers.

In the present invention, the surface of the fine particles of the inorganic layered clay compound is preferably hydrophobized with a hydrophobizing agent, and the number average primary particle size of the fine particles of the inorganic layered clay compound is 0.3 to 0.00. 7 μm Ru der.

Further, in the present invention, the inorganic layered clay compound, Ru smectite der.

According to the present invention, external additive is, pieces number average primary particle diameter of fine particles of 5 to 15 nm (A), and the number average primary particle diameter is contained fine particles of 20 to 200 nm (B). Further, the fine particles (A) and fine particles (B), Ru Oh in particulate independently silica or titania.

  According to the present invention, there is provided an electrostatic charge image developing toner which has excellent printing durability not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment and which does not cause fogging in a wider toner charge amount region.

  Hereinafter, the toner for developing an electrostatic image of the present invention (hereinafter, “toner for developing an electrostatic image” is also simply referred to as “toner”) and a manufacturing method thereof will be described.

The toner of the present invention contains colored resin particles, a charge control agent and an external additive, and the colored resin particles are particles containing a binder resin and a colorant, and if necessary , Other additives such as a release agent and a pigment dispersant may be contained.

  Specific examples of the binder resin include conventionally widely used resins such as polystyrene, styrene-butyl acrylate copolymer, polyester resin, and epoxy resin.

  In the present invention, the method for producing the colored resin particles is not particularly limited, and examples thereof include a pulverization method and a polymerization method. The toners obtained by these methods are called pulverized toner and polymerized toner, respectively. As the toner of the present invention, a polymerized toner is preferable because it has a relatively small particle size distribution on the order of microns. Examples of the polymerization method include emulsion polymerization aggregation method, dispersion polymerization method, suspension polymerization method and the like, and suspension polymerization method is preferable.

When the colored resin particles are produced by employing the polymerization method, the following process is performed. First, a polymerizable monomer, a charge control agent, a colorant, and other additives as necessary are mixed to obtain a polymerizable monomer composition. This polymerizable monomer composition is placed in an aqueous medium containing a dispersion stabilizer as necessary, and then a polymerization initiator is added to form droplets. Thereafter, polymerization is performed to obtain an aqueous dispersion of colored resin particles. This aqueous dispersion is washed, dehydrated and dried to obtain dried colored resin particles. The dried colored resin particles are classified as necessary, and an external additive and a carrier as necessary are added to obtain a polymerized toner.

(1) Polymerizable monomer composition The polymerizable monomer refers to a polymerizable compound.
It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Monovinyl monomers include: styrene; styrene derivatives such as vinyltoluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate And acrylic acid esters such as dimethylaminoethyl acrylate; methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and dimethylaminoethyl methacrylate; acrylamide, methacrylic Derivatives of acrylic acid such as amide and methacrylic acid; olefins such as ethylene, propylene, and butylene. These monovinyl monomers may be used alone or in combination. Of these, styrene, styrene derivatives, and acrylic acid or methacrylic acid derivatives are preferably used as monovinyl monomers.

  The monovinyl monomer is preferably selected so that the glass transition temperature (hereinafter referred to as Tg) of the polymer obtained by polymerizing the monovinyl monomer is 80 ° C. or lower. By using monovinyl monomers alone or in combination of two or more, the Tg of the polymer can be adjusted to a desired range.

In order to improve hot offset, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer as a part of the polymerizable 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; unsaturated polycarboxylic acids of polyhydric alcohols such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate Polyester; N, N-divinylaniline and other divinyl compounds such as 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 weight, preferably 0.3 to 2 parts by weight, with respect to 100 parts by weight of the monovinyl monomer. desirable.

  Further, it is preferable to use a macromonomer as a part of the polymerizable monomer because the balance between the storage stability of the toner and the fixing property at a 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 a monovinyl monomer. The amount of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, and more preferably 0.05 to 1 part by weight with respect to 100 parts by weight of the monovinyl monomer.

In the present invention, a colorant is used. However, when producing a color toner, normally, black, cyan, yellow, and magenta colorants are used. Other colorants such as white colorants such as titanium dioxide can also be used.
In the colorant in the present invention, as the black colorant, colorants and dyes such as carbon black, titanium black, magnetic powders such as iron oxide zinc and iron oxide nickel, and oil black can be used.

As the cyan colorant, a copper phthalocyanine compound, a derivative thereof, an anthraquinone compound, and the like can be used.
As the yellow colorant and magenta colorant, compounds such as monoazo pigments, azo pigments such as disazo pigments, and condensed polycyclic pigments are used.
The amount of each colorant is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  In order to improve the dispersion state of the colorant in the colored resin particles, it is preferable to treat the surface of the colorant with a pigment dispersant. As the pigment dispersant, a coupling agent such as an aluminum coupling agent, a silane coupling agent, and a titanium coupling agent is preferable.

In the present invention, colored resin particles, it contains a charge control agent. When producing a negatively chargeable toner, a negatively chargeable charge control agent is mainly used, and when producing a positively chargeable toner, a positively chargeable charge control agent is mainly used. A small amount of a charge control agent having a polarity opposite to that of the main charge control agent may be used.

  Examples of positively chargeable charge control agents include charge control resins such as polyamine resins, tertiary amino group-containing copolymers, and quaternary ammonium base-containing copolymers; imidazole compounds, nigrosine dyes, quaternary ammonium salts, and triglycerides. Examples include aminotriphenylmethane compounds.

Negatively chargeable charge control agents include sulfonic acid group-containing copolymers, sulfonate group-containing copolymers, carboxylic acid group-containing copolymers, and charge control resins such as carboxylic acid group-containing copolymers, and Cr. Azo dyes containing metals such as Co, Al, and Fe, salicylic acid metal compounds, and alkyl salicylic acid metal compounds.
It is preferable to use a charge control resin as the charge control agent because the printing durability of the toner becomes good. When the charge control resin is used, the addition amount is preferably 0.01 to 30 parts by weight, and more preferably 0.3 to 25 parts by weight with respect to 100 parts by weight of the binder resin.

Further, as other additives, it is preferable to add a release agent since 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. Low molecular weight polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; low molecular weight oxidized low molecular weight polypropylene, low molecular weight terminal-modified polypropylene having molecular ends substituted with epoxy groups, block polymers of these and low molecular weight polyethylene, and molecules Terminal-modified low-molecular-weight polyethylene, low-molecular-weight polyethylene whose molecular ends are substituted with epoxy groups, and terminal-modified polyolefin waxes such as these and low-molecular-weight polypropylene block polymers; natural waxes such as candelilla, carnauba, rice, wood wax, and jojoba; Petroleum waxes such as paraffin, microcrystalline, and petrolactam, and modified waxes thereof; mineral waxes such as montan, ceresin, and ozokerite; Fischer Trop Synthetic waxes such as New Wax; pentaerythritol esters such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and pentaerythritol tetralaurate, dipentaerythritol hexamyristate, dipentaerythritol hexapalmitate, And polyhydric alcohol esterified products such as dipentaerythritol esters such as dipentaerythritol hexalaurate; and the like. Among them, a polyhydric alcohol ester is preferable because it improves the low-temperature fixability of the toner and does not deteriorate the printing durability. These may be used individually by 1 type and may be used in combination of 2 or more type.
The release agent is preferably used in an amount of 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the monovinyl monomer.

  It is preferable to use a molecular weight modifier as another additive. Examples of the molecular weight modifier include mercaptan compounds such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2,4,6,6-pentamethylheptane-4-thiol. The amount of the molecular weight modifier is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

(2) Droplet formation In the present invention, the polymerizable monomer composition obtained as described above is dispersed in an aqueous medium containing a dispersion stabilizer, and after adding a polymerization initiator, the polymerization property is increased. The droplet formation of the monomer composition is performed. The method for forming droplets is not particularly limited, and examples thereof include an in-line type emulsifier / disperser (trade name: Milder, manufactured by Ebara Seisakusho Co., Ltd.) and a high-speed emulsifier / disperser (trade name: TK, manufactured by Special Machine Industries Co., Ltd.). A homomixer MARK II type) or the like capable of strong stirring is used.

  In the present invention, the aqueous medium may be water alone, but a solvent that is soluble in water, such as a lower alcohol and a lower ketone, may be used in combination.

  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; 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, the dispersion stabilizer containing a metal compound, particularly a colloid of a hardly water-soluble metal hydroxide, can narrow the particle size distribution of the colored resin particles, and can stabilize the dispersion after washing. Since the residual amount of the agent is small, the obtained polymerized toner is preferable because it can reproduce an image clearly and does not deteriorate the image quality under high temperature and high humidity.

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), 2,2′-azobisisobutyronitrile, etc. Di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxypivalate, Such as diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate Machine peroxides. Among these, it is possible to reduce the residual polymerizable monomer, since it is excellent also printing durability, it is preferable to use an organic peroxide.
As described above, the polymerization initiator may be added after the polymerizable monomer composition is dispersed in the aqueous medium and before droplet formation, but is added to the polymerizable monomer composition. May be.

  The addition amount of the polymerization initiator used for polymerization of the polymerizable monomer composition is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 100 parts by weight of the monovinyl monomer. -15 parts by weight, most preferably 1.0-10 parts by weight.

(3) Polymerization As described above, droplet formation is performed, the obtained aqueous medium is heated, polymerization is started, and an aqueous dispersion of colored resin particles is obtained.
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 toner by adding an external additive as it is. However, the colored resin particles are used as a core layer, and a so-called core-shell type obtained by forming a shell layer different from the core layer on the outer side. It is preferable to use colored resin particles. The core-shell type colored resin particles are coated with a core layer made of a substance having a low Tg with a substance having a higher Tg, thereby lowering the fixing temperature (low-temperature fixability) and preventing aggregation during storage (preservability). ).

  There is no restriction | limiting in particular as a method of manufacturing a core shell type colored resin particle using the colored resin particle obtained by the polymerization method 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.
Polymerization is performed by adding a polymerizable monomer (shell polymerizable monomer) and a polymerization initiator for forming a shell layer into an aqueous medium in which colored resin particles obtained by the polymerization method are dispersed. Thus, core-shell type colored resin particles can be obtained.

  As the polymerizable monomer for the shell, those similar to the monovinyl monomer described above 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.

  Polymerization initiators used for polymerization of the polymerizable monomer for shell include potassium persulfate and persulfate metal salts such as ammonium persulfate; 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) Water-soluble polymerization initiation such as propionamide) and azo initiators such as 2,2′-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); An agent can be mentioned. The amount of the polymerization initiator is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell.

(4) Filtration, washing, dehydration, and drying The aqueous dispersion of colored resin particles obtained by polymerization is subjected to filtration, removal of the dispersion stabilizer, removal, and drying according to a conventional method after the completion of the polymerization. The operation is performed to obtain colored resin particles by a polymerization method.

  As the above washing method, when an inorganic compound such as an inorganic hydroxide is used as the dispersion stabilizer, the dispersion stabilizer is made into water by adding acid or alkali to the aqueous dispersion of colored resin particles. It is preferable to dissolve and remove. When a colloid of a hardly 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 are not particularly limited. For example, a centrifugal filtration method, a vacuum filtration method, a pressure filtration method, and the like can be given. Also, the drying method is not particularly limited, and various methods can be used.

  When the colored resin particles are produced using the pulverization method, the following process is performed. Specifically, first, a binder resin, a colorant, and, if desired, a release agent and a charge control agent are mixed in a mixer, such as a ball mill, a V-type mixer, a Henschel mixer (: trade name), a high-speed dissolver, an interpolator. Mix using a Null mixer, Fallberg, 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 and a high-speed rotary pulverizer, it is classified into a desired particle size by a classifier such as an air classifier and an airflow classifier, and a colored resin obtained by a pulverization method. Get particles. As the colorant used in the pulverization method, and the release agent and charge control agent used as desired, those described in the above polymerization method can be used.

  The colored resin particles obtained by the above pulverization method can be made into core-shell type colored resin particles by a method such as an in situ polymerization method, similarly to the colored resin particles obtained by the polymerization method described above.

  As described above, colored resin particles can be obtained by the polymerization method or the pulverization method. Hereinafter, the colored resin particles or the core-shell type colored resin particles constituting the toner of the present invention will be described (the following colored resin particles include both the core-shell type and those not).

  The volume average particle diameter (Dv) of the colored resin particles is preferably 3 to 15 μm, more preferably 4 to 12 μm. If Dv is less than these ranges, the fluidity of the toner may decrease, transferability may deteriorate, blurring may occur, and image density may decrease, and if these ranges are exceeded, the resolution of the image decreases. There is a case.

  The ratio (Dv / Dp) of the volume average particle diameter (Dv) and the number average particle diameter (Dp) of the colored resin particles is preferably 1.00 to 1.30, more preferably 1.00. 1.20. When Dv / Dp exceeds these ranges, blurring may occur, and transferability, image density, and resolution may decrease.

The colored resin particles constituting the toner of the present invention are preferably those having a sphericity (Sc / Sr) of 1.00 to 1.30, and a sphericity (Sc / Sr) of 1.00 to 1. It is more preferable to use one that is .20. If the sphericity (Sc / Sr) exceeds these ranges, the transferability may be reduced, or the fluidity of the toner may be reduced, and the toner may be easily lost. The sphericity (Sc / Sr) of the colored resin particles is obtained as follows. Colored resin particles are photographed with an electron microscope, and the resulting photographs are image processing analyzer (trade name: Luzex IID, manufactured by Nireco Co., Ltd.). Measure under the following conditions. It is obtained by averaging the sphericity (Sc / Sr) of the 100 colored resin particles obtained.
Sphericality = Sc / Sr
Sc: Area of a circle having the absolute maximum length of the colored resin particles as a diameter Sr: Real projected area of the colored resin particles

(5) External Addition To adjust the chargeability, fluidity, storage stability, etc. of the toner, the toner of the present invention is mixed with colored resin particles and external additives using a high-speed stirrer (external addition). Or a one-component toner, or carrier particles such as colored resin particles and external additives, and ferrite and iron powder are mixed to form a two-component toner.

  The external additive is coated with the colored resin particles by mixing and stirring the colored resin particles and the external additive using a mixer. Henschel mixer (: trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (: trade name, manufactured by Kawada Seisakusho), Q mixer (: trade name, manufactured by Mitsui Mining Co., Ltd.), mechano-fusion system (: commercial product) Name, manufactured by Hosokawa Micron Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), and the like.

  When two or more types of external additives are used in combination, the colored resin particles and all external additives may be added externally in a high-speed stirrer, but only the colored resin particles and the large external additive are high-speed. After the external addition in a stirrer, the external addition is preferably performed by further adding an external additive having a smaller particle size.

In the present invention, fine particles of an inorganic layered clay compound in which quaternary ammonium ions are intercalated between layers are used as an external additive.
Examples of inorganic layered clay compounds include kaolinites such as kaolinite, dickite, halloysite, and lizarsite; smectites such as montmorillonite, hydelite, nontronite, hectorite, and saponite; phlogopite, biotite, muscovite, Mica (mica) group such as paragonite and sericite; chlorite group such as clinochlore, chamosite, penantite and donbasite; talc-pyrophyllite group such as talc, willemsite, kerolite and pyrophyllite; . Among these, smectite groups such as montmorillonite, hydelite, nontronite, hectorite, saponite are preferable, and bentonite, which is clay mainly composed of montmorillonite, is more preferable.
In the inorganic layered clay compound as described above, an alkali metal or alkaline earth metal cation usually exists between the layers. It is known that these cations are weakly bound to a layer portion and a cation exchange reaction occurs when they come into contact with a solution containing other cations. Such a reaction of incorporating different kinds of ions or molecules between layers is called “intercalation”.

  Examples of the method for performing the intercalation in the present invention include a method in which an inorganic layered clay compound is dispersed in an aqueous medium such as lower alcohol or water, and a quaternary ammonium salt is added thereto, followed by heating with stirring. . This agitation is, for example, strong agitation such as an in-line type emulsifying disperser (manufactured by Ebara Manufacturing Co., Ltd., trade name: Milder), a high speed emulsifying disperser (trade name: TK Homomixer MARK II type). It is preferable to use an apparatus capable of

  As the quaternary ammonium salt used for intercalation in the present invention, a tetraalkylammonium cation, an ammonium cation having a benzyl group and an alkyl group, a pyridinium cation, and the like can be used. Examples of anions constituting these quaternary ammonium salts include hydroxide ions, halogen ions (fluorine ions, chlorine ions, bromine ions and iodine ions), nitrate ions, nitrite ions, and methosulphate ions. Ions are preferred.

  As the tetraalkylammonium cation, an ammonium cation composed of an alkyl group having 1 to 22 carbon atoms can be used. As quaternary ammonium salts composed of these, lauryl trimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, didecyl dimethyl ammonium chloride, cetyl trimethyl ammonium chloride, dimethyl dioctyl ammonium bromide, trimethyl stearyl ammonium bromide, dimethyl distearyl ammonium chloride, cetyl trimethyl ammonium Examples include methosulfate, stearamide ethyl diethyl methyl ammonium methosulfate, and lauryl amido ethyl diethyl methyl ammonium methosulfate.

As an ammonium cation having a benzyl group and an alkyl group, an ammonium cation having a benzyl group and an alkyl group having 1 to 22 carbon atoms can be used. As an ammonium salt comprising these, for example, benzyl lauryl dimethyl ammonium chloride ( Benzalkonium chloride) and benzyldimethyloctylammonium methosulfate.
As the pyridinium cation, a pyridinium cation having an alkyl group (8 to 22 carbon atoms) can be used, and examples thereof include N-cetylpyridinium chloride, N-oleylpyridinium chloride, N-laurylpyridinium chloride and N-laurylpyridinium methosulfate. It is done.

  In the present invention, it is preferable that the fine particles of the inorganic layered clay compound have been subjected to a hydrophobic treatment. As the hydrophobizing agent, for example, a silane coupling agent, silicone oil, fatty acid, fatty acid metal salt, and the like can be used. Among these, a silane coupling agent and silicone oil are preferable. Examples of silane coupling agents include disilazane such as hexamethyldisilazane; cyclic silazane; trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane. , Methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-butyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, Alkylsilane compounds such as vinyltriacetoxysilane, γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, N- Aminosilanes such as phenyl-3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, and N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane Compound; and the like. Examples of the silicone oil include dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, and amino-modified silicone oil. Among the above, the hydrophobizing agent may be contained alone or in combination of two or more. When a silicone oil or a silane coupling agent is used, the resulting toner is more preferable because it provides high image quality. . Further, it is more preferable to use an amino group-containing compound such as an aminosilane compound or an amino-modified silicone oil because a toner having good positive chargeability can be easily obtained.

  In the present invention, as a method for hydrophobizing the fine particles of the inorganic layered clay compound, a general method can be used, and examples thereof include a dry method and a wet method. Specifically, the method of dropping or spraying the hydrophobic treatment agent while stirring the fine particles at a high speed, and the method of dissolving the hydrophobic treatment agent in an organic solvent and stirring the organic solvent containing the treatment agent The method of adding etc. is mentioned.

The number average primary particle diameter of the fine particles of the inorganic layered clay compound used for intercalation of the above SL is preferably from 0.1 to 10 [mu] m, more preferably 0.2 to 0.8 [mu] m, even more preferably 0 .3 to 0.7 μm. In this invention, it is 0.3-0.7 micrometer.
Further, the amount of fine particles of the inorganic layered clay compound is preferably 0.05 to 2 parts by weight, more preferably 0.05 to 1 part by weight, with respect to 100 parts by weight of the colored resin particles. Part is particularly preferred. In this invention, it is 0.1-0.5 weight part.

  In the present invention, the external additive further includes fine particles having a number average primary particle size of 5 to 15 nm (hereinafter referred to as “fine particles (A)”) and fine particles having a number average primary particle size of 20 to 200 nm ( Hereinafter, it is preferable to contain “fine particles (B)”. The fine particles (A) and the fine particles (B) are made of silica or titania (titanium dioxide).

The number average primary particle size of the fine particles (A) is 5 to 15 nm, and more preferably 5 to 15 nm. When the number average primary particle size is in this range, a good printed image with good fluidity and no blur can be obtained. The fine particles (A) are preferably those which have been subjected to a hydrophobic treatment by treating the surface of the fine particles with a hydrophobic treatment agent.
The number average primary particle size of the fine particles (B) is 20 to 200 nm, more preferably 25 to 100 nm. When the number average primary particle size is in this range, a toner with less fog is obtained, and the effect of the fine particles of the inorganic layered clay compound of the present invention is easily obtained in printing durability.

  In the present invention, preferably used fine particles (A) and fine particles (B) are also preferably hydrophobized, and the hydrophobizing agent and the hydrophobizing method are the same as in the case of the fine particles of the inorganic layered clay compound. Can be done.

0.1-3 weight part is preferable with respect to 100 weight part of colored resin particles, and, as for the quantity of microparticles | fine-particles (A), 0.3-1.5 weight part is more preferable.
The amount of the fine particles (B) is preferably 0.1 to 3 parts by weight, and more preferably 0.3 to 2 parts by weight with respect to 100 parts by weight of the colored resin particles.

In the present invention, as the external additive, other fine particles may be used as necessary. For example, inorganic fine particles such as aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and cerium oxide; methacrylate polymer, acrylate polymer, styrene-methacrylate copolymer, styrene-acrylic acid And ester resin, melamine resin, and organic resin particles such as core-shell particles in which the core is a styrene polymer and the shell is a methacrylic ester polymer.
The amount of the other fine particles is 0.1 to 3 parts by weight, preferably 0.2 to 2 parts by weight with respect to 100 parts by weight of the colored resin particles.

  The toner for developing an electrostatic charge image of the present invention has excellent printing durability not only in a normal temperature and normal humidity environment but also in a high temperature and high humidity environment, and fog does not occur in a wider toner charge amount region.

The production method of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.
The test methods performed in this example are as follows.

(Physical properties of colored resin particles)
(1) Volume average particle size and particle size distribution The volume average particle size (Dv) of the colored resin particles, and the particle size distribution, that is, the ratio (Dv / Dp) of the volume average particle size to the number average particle size (Dp) is: Measured with a multisizer (Beckman Coulter, Inc.). The measurement with this multisizer was performed under the conditions of an aperture diameter: 100 μm, a medium: Isoton II, a concentration of 10%, and a number of measured particles: 100,000.

(Physical properties of external additives)
(2) Number average primary particle size The number average primary particle size of the fine particles of the inorganic layered clay compound and the fine particles of the external additive was determined by the following method as the number average primary particle size. First, an electron micrograph of each particle is taken, and the photograph is taken by an image processing analyzer (trade name: Luzex IID, manufactured by Nireco Corporation). The area ratio of particles to the frame area: 2% at maximum, the total number of particles processed: 100 Under the conditions, the equivalent circle diameter corresponding to the projected area of the particles was calculated, and the arithmetic average value was obtained.

(Print test)
(3) Printing durability (NN environment, HH environment)
Using a commercially available non-magnetic one-component developing type printer, printing paper was set, and toner was put in the developing device. After being allowed to stand for 24 hours in a normal temperature and normal humidity (NN) environment at a temperature of 23 ° C. and a humidity of 50% RH, continuous printing was performed at a print density of 5% in the same environment. Solid printing (printing density 100%) was performed every 500 sheets, and the printing density of the solid printing part was measured with a reflective image densitometer (trade name: RD918, manufactured by Macbeth). After that, white solid printing (print density 0%) is performed, the printer is stopped in the middle of white solid printing, and the toner in the non-image area on the photoconductor after development is adhesive tape (manufactured by Sumitomo 3M Limited, product Name: Scotch mending tape 810-3-18) and adhered to printing paper. Next, the whiteness (B) of the printing paper with the adhesive tape attached is measured with a whiteness meter (Nippon Denshoku Co., Ltd.), and in the same way, only the unused adhesive tape is attached to the printing paper. The whiteness (A) was measured, and the difference in whiteness (B−A) was defined as a fog value (%). Smaller values indicate better fogging.
The number of continuous prints capable of maintaining the image density of 1.3 or more and the fog value of 3 or less was examined, and the number was determined as the durable print number in the NN environment.
Similarly, a printing durability test was performed in a high temperature and high humidity (HH) environment of 30 ° C. and 80% RH, and a durable printing number in an HH environment was obtained.
The test was conducted up to 15,000 continuous prints, and “15,000 <” in the test result indicates that the above criteria are satisfied even if 15,000 prints are made continuously.

(3) Toner charge at end of durability (NN environment)
In the NN environment printing durability test in (2), when fog is generated and the durability is finished, the charge amount (μC / g) of the toner adhering to the developing roll is measured by a suction-type charge amount measuring device (Trek Japan Co., Ltd.). Manufactured, product name: 210HS-2A). The test result “15,000 <” was measured when the print durability test was completed for 15,000 sheets.

(Inorganic layered clay compound fine particle production example 1)
After 150 parts of bentonite having a number average primary particle size of 0.5 μm was dispersed in 1,500 parts of ion-exchanged water, 15 parts of dimethyl distearyl ammonium chloride (quaternary ammonium salt) was added. Subsequently, the obtained dispersion was heated to 80 ° C., and then stirred for 1 hour by a high-speed emulsification disperser (trade name: TK Homomixer MARK II type, manufactured by Tokushu Kika Kogyo Co., Ltd.). An inorganic layered clay compound in which the solid content obtained by filtration is repeatedly washed with deionized water, dehydrated, dried by a vacuum dryer at 60 ° C. for 24 hours, and dimethyl distearyl ammonium is intercalated between the layers. Fine particles 1 were obtained.

(Inorganic layered clay compound fine particle production example 2)
The obtained inorganic layered clay compound fine particles 1 were hydrophobized by the following method to obtain inorganic layered clay compound fine particles 2. The number average primary particle size of the obtained fine particles was 0.5 μm.
After putting 100 g of inorganic layered clay compound fine particles 1 into a container, vaporized N-phenyl-3-aminopropyltrimethoxysilane (amino group-containing silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd., trade name) : KBM-573)) 16 g was introduced along with nitrogen, and the inorganic layered clay compound fine particles 1 and the gasified amino group-containing silane coupling agent were brought into contact with each other to carry out a hydrophobic treatment.

(Inorganic layered clay compound fine particle production examples 3 to 6)
Inorganic layered clay compound fine particles 3 to 4 were produced in the same manner as in the inorganic layered clay compound fine particle 1, except that dimethyl distearyl ammonium chloride was changed to lauryl pyridinium chloride and benzyl lauryl dimethyl ammonium chloride, respectively. The same operations as in Example 1 were performed, and further, a hydrophobic treatment was performed in the same manner as in Production Example 2 of the inorganic layered clay compound fine particles. The number average primary particle size of the obtained fine particles was 0.5 μm.
The inorganic layered clay compound fine particle 5 is the same as the inorganic layered clay compound fine particle production example 1 except that the bentonite having a number average primary particle size of 0.5 μm is changed to kaolinite having a number average primary particle size of 1 μm. This was obtained by performing the operation and further performing a hydrophobizing treatment in the same manner as in Production Example 2 of the inorganic layered clay compound fine particles. The number average primary particle size of the obtained fine particles was 1 μm.
The inorganic layered clay compound fine particle 6 is obtained by performing only the hydrophobization treatment similar to that in Production Example 2 of the inorganic layered clay compound fine particle without intercalating the kaolinite used in the inorganic layered clay compound fine particle 5 with an ammonium salt. Obtained. The number average primary particle size of the obtained fine particles was 1 μm.

Example 1
83 parts of styrene as monovinyl monomer and 17 parts of n-butyl acrylate (calculation of the resulting copolymer Tg = 60 ° C.), 7 parts of carbon black (trade name: # 25B, manufactured by Mitsubishi Chemical Corporation) as a black colorant, 1 part of a charge control agent (styrene / acrylic resin, manufactured by Fujikura Kasei Co., Ltd., trade name: FCA-207P), 0.6 part of divinylbenzene as a crosslinkable monomer, 1.9 parts of t-dodecyl mercaptan as a molecular weight modifier, Then, 0.25 part of a polymethacrylic acid ester macromonomer (trade name: AA6, manufactured by Toa Gosei Kagaku Kogyo Co., Ltd.) as a macromonomer was stirred and mixed, and then wet pulverized by a media type wet pulverizer. A polymerizable monomer composition was obtained by adding and dissolving 5 parts of dipentaerythritol hexamyristate as a release agent to the composition obtained by wet pulverization.
Separately, at room temperature, an aqueous solution in which 6.2 parts of sodium hydroxide is dissolved in 50 parts of ion-exchanged water and an aqueous solution in which 6.2 parts of sodium hydroxide are dissolved in 250 parts of ion-exchanged water are gradually added with stirring. Then, a magnesium hydroxide colloid (hardly water-soluble metal hydroxide colloid) dispersion was prepared.

  The polymerizable monomer composition is charged into the magnesium hydroxide colloidal dispersion obtained as described above and stirred, and t-butylperoxy-2-ethylhexanoate (Nippon Yushi) as a polymerization initiator is added thereto. After adding 6 parts by a company, product name: Perbutyl O), droplets were formed by high-shear stirring using an in-line type emulsifying disperser (trade name: Ebara Milder, manufactured by Ebara Seisakusho Co., Ltd.).

  The droplet-formed polymerizable monomer composition aqueous dispersion was put into a reactor and heated to 90 ° C. to carry out a polymerization reaction. A dispersion obtained by mixing 1 part of methyl methacrylate (polymerizable monomer for shell) and 10 parts of ion-exchanged water and ion-exchanged water when the polymerization conversion rate reaches almost 100% 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide)) dissolved in 20 parts) (polymerization initiator for shell, manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086) 0 3 parts were added. Then, after maintaining at 90 degreeC for further 4 hours and continuing superposition | polymerization, it cooled to room temperature and obtained the aqueous dispersion of the colored resin particle.

To the obtained aqueous dispersion of colored resin particles, sulfuric acid is added to adjust the pH to 6.5 or lower, acid washing is performed, dehydration is performed by filtration, and 500 parts of ion-exchanged water is again added to reslurry. And water washing. Thereafter, similarly, dehydration and water washing were repeated several times, and after dehydration by filtration, the dehydrated resin was placed in a drier container and dried at a temperature of 45 ° C. for 48 hours to obtain dried colored resin particles.
The volume average particle diameter (Dv) of the dried colored resin particles is 9.1 μm, the volume average particle diameter (Dv) / number average particle diameter (Dp) is 1.14, and the sphericity (Sc / Sr) is 1. .12.

  To 100 parts of the colored resin particles obtained as described above, 0.8 parts of silica fine particles (manufactured by Clariant, trade name: HDK2150) having a number average primary particle size of 12 nm subjected to a hydrophobic treatment as fine particles (A), As fine particles (B), 1 part of hydrophobized silica fine particles having a number average primary particle size of 30 nm (manufactured by Nippon Aerosil Co., Ltd., trade name: NA50Y) and inorganic layered clay compound fine particle production example 2 were obtained. 0.2 parts of clay compound fine particles 2 were added and mixed using a high speed stirrer (Mitsui Mining Co., Ltd., trade name: Henschel mixer) for 5 minutes at a peripheral speed of 30 m / s. A toner for developing an electrostatic image of the component was prepared.

(Example 2)
A non-magnetic one-component electrostatic image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were changed to the inorganic layered clay compound fine particles 1 in Example 1. The test results are shown in Table 1.

(Example 3)
A non-magnetic one-component electrostatic charge image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were changed to the inorganic layered clay compound fine particles 3 in Example 1. The test results are shown in Table 1.

Example 4
A non-magnetic one-component electrostatic charge image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were changed to the inorganic layered clay compound fine particles 4 in Example 1. The test results are shown in Table 1.

(Example 5)
A non-magnetic one-component electrostatic image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were changed to the inorganic layered clay compound fine particles 5 in Example 1. The test results are shown in Table 1.

(Comparative Example 1)
In Example 1, a non-magnetic one-component electrostatic charge image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were not used. The test results are shown in Table 1.

(Comparative Example 2)
A non-magnetic one-component electrostatic charge image developing toner was prepared in the same manner as in Example 1 except that the inorganic layered clay compound fine particles 2 were changed to the inorganic layered clay compound fine particles 6 in Example 1. The test results are shown in Table 1.

From the test results described in Table 1, the following can be understood.
In Comparative Example 1 in which an inorganic layered clay compound intercalated with quaternary ammonium ions was not used as an external additive, images after printing 5,000 sheets and 2,000 sheets in an NN environment and an HH environment, respectively. The density decreased and fogging occurred, and the toner charge amount at that time was 18 μC / g.
In Comparative Example 2 using the inorganic layered clay compound 6 in which quaternary ammonium ions were not intercalated as an external additive, although similar to Comparative Example 1, the results were similar.
On the other hand, in the toner of the example containing inorganic layered clay compound fine particles in which quaternary ammonium ions are intercalated between layers of the inorganic layered clay compound as an external additive, printing in an NN environment and an HH environment is performed. In the durability test, excellent printing durability was exhibited, and fog was hardly generated even when the toner charge amount was low.

Claims (2)

In a toner for developing an electrostatic image containing a binder resin , colored resin particles containing a charge control agent and a colorant, and an external additive,
(I) The external additive is 0.1 to 0.5 part by weight of a fine particle of an inorganic layered clay compound having a number average primary particle size of 0.3 to 0.7 μm with respect to 100 parts by weight of the colored resin particles, the number average. 0.1 to 3 parts by weight of the fine particles (A) having a primary particle diameter of 5 to 15 nm with respect to 100 parts by weight of the colored resin particles, and 100 parts by weight of fine particles (B) having a number average primary particle diameter of 20 to 200 nm. 0.1 to 3 parts by weight with respect to parts , and the fine particles (A) and the fine particles (B) are each independently silica or titania fine particles, and
(Ii) inorganic layered clay compound, a toner for developing electrostatic images, which is a smectite group of quaternary ammonium ions between the layers are intercalated.   2. The electrostatic image developing toner according to claim 1, wherein the surface of the fine particles of the inorganic layered clay compound is subjected to a hydrophobic treatment with a hydrophobic treatment agent.