JP2008096821A - Toner for electrostatic charge image development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, correspondingly to an image forming apparatus of a toner supply system, upon the supply of a toner, in which fogging is hard to be generated since its charge stability is excellent and charge rising properties are satisfactory, and, even upon the repeated printing of a toner, the charge stability of the toner can be maintained and printing durability is excellent since the change of the surface conditions in the toner particles can be reduced. <P>SOLUTION: In the toner for electrostatic charge image development comprising: colored resin particles containing a binding resin and a colorant; and an external additive, the external additive comprises: inorganic particulates having a perovskite type crystal structure; and inorganic layered clay compound particulates. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is an electrostatic charge image developing toner (hereinafter, sometimes simply referred to as “toner”) used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. More specifically, the present invention relates to an electrostatic charge image developing toner that can be applied to a toner replenishment type image forming apparatus.

  Image forming apparatuses such as an electrophotographic apparatus, an electrostatic recording apparatus, and an electrostatic printing apparatus form a desired image by developing an electrostatic latent image formed on a photoreceptor with toner for developing an electrostatic image. The method is widely implemented and applied to copiers, printers, facsimiles, and multi-function machines.

  For example, in an electrophotographic apparatus using electrophotography, generally, a surface of a photoconductor made of a photoconductive material is uniformly charged by various means, and then an electrostatic latent image is formed on the photoconductor. Then, the electrostatic latent image is developed using toner, and the toner image is transferred to a recording material such as paper as necessary, and then fixed by heating, pressurization, solvent vapor, etc. to obtain a copy. . Further, toner remaining without being transferred onto the photoreceptor (residual toner) is cleaned by various methods, and the above-described steps are repeated. As the cleaning means, a blade cleaning means having a structure in which a cleaning blade made of a rubber elastic material is brought into pressure contact with a photoreceptor is widely used.

  The toner used in the conventional image forming apparatus as described above is filled in the cartridge in which the photoconductor is incorporated, and when the remaining toner is low, an exchange system is used in which the cartridge is replaced. At present, there is a development of a replenishment type image forming apparatus capable of newly replenishing the remaining toner (remaining toner) due to the demand from the environmental aspect and the cost aspect of using the toner efficiently without waste. Development of a toner (replenishment toner) that can be applied to this toner replenishment type image forming apparatus is desired.

In general, fine particles, which are external additives, are externally added to the surface of toner particles for the purpose of improving fluidity, charging stability, durability, and the like.
In the toner replenishing type image forming apparatus, while the toner is new, the external additive is uniformly added to the surface of the toner particles, so that it exhibits good fluidity, charging stability and durability. However, since the residual toner after performing durable printing (continuous mass printing) is caused by stress in the developing device or the like, the external additive is buried in the surface of the toner particles or released from the toner surface. As the fluidity of the toner decreases, it becomes difficult to maintain the charging stability of the toner.

  When replenishment toner is added to the remaining toner, the amount of charge varies depending on the surface condition of the toner particles. Since the old toner and new toner are mixed, the triboelectric chargeability also changes greatly (charging fluctuation) and electrostatic aggregation occurs mutually. Thus, there is a problem that stable development cannot be performed.

  In Patent Document 1, for the purpose of reducing the toner charge fluctuation, the saturation value (μ1) of the charge amount of toner (residual toner) over time in the toner hopper and the newly replenished toner (supplement toner) A non-magnetic one-component toner is disclosed in which the relationship between the charge amount and the saturation value (μ2) is defined as μ1 ≦ μ2. However, it is not necessarily certain that the toner disclosed in Patent Document 1 has a sufficient effect of reducing the change in surface state (charge fluctuation) of the toner particles even by durable printing.

  In response to the above problems, strontium titanate has a characteristic that the charge is almost neutral and the change in the charge level is small, and has been conventionally used as an external additive for toner. Further, strontium titanate having a specific crystal structure has a polishing effect in addition to the above effects. For this reason, it is known that the cleaner portion can be given an abrasive property and has an effect of preventing the toner component from adhering to the photoreceptor (black spot (BS)).

  In Patent Document 2, the addition of strontium titanate fine particles having a number average particle diameter of 80 to 800 nm as an external additive stabilizes the charge amount of the toner and gives the cleaner part abrasiveness. Toners that prevent harmful effects such as (BS) are disclosed.

  In Patent Document 3, strontium titanate fine particles having a cubic particle shape and / or a rectangular parallelepiped particle shape having a number average particle diameter of 30 to 300 nm and having a perovskite crystal are added as an external additive. Thus, a toner having an excellent polishing effect is disclosed.

  However, even when the strontium titanate fine particles disclosed in Patent Documents 2 and 3 were used as external additives, there was an effect of suppressing fogging immediately after toner replenishment. It has been found out by the present inventors that the effect is not necessarily sufficient.

JP 2004-126324 A Japanese Patent Laid-Open No. 10-10770 JP 2005-338750 A

  An object of the present invention is to correspond to a toner replenishment type image forming apparatus, and at the time of toner replenishment, it is excellent in charging stability of the toner and has good charge rise, so that fog is hardly generated and toner is repeatedly printed. Even at times, it is possible to reduce the change in the surface state of the toner particles, and thus to provide a toner for developing an electrostatic charge image that can maintain the charging stability of the toner and has excellent printing durability.

  As a result of intensive investigations to achieve the above object, the present inventors have used inorganic fine particles having a perovskite crystal structure and inorganic layered clay compound fine particles as external additives. Because toner particles are not buried in the surface or released from the surface of the toner, the change in the surface state of the toner particles is small and the fluidity of the toner can be stably maintained. In addition, the inorganic layered clay compound fine particles assist the rise of toner charge during printing endurance, so that the toner charge can be maintained even during repeated printing of toner. Finding that stability can be maintained and printing durability can be improved, and the present invention is completed based on these findings Led was.

That is, the toner for developing an electrostatic charge image of the present invention is a toner for developing an electrostatic charge image containing a colored resin particle containing a binder resin and a colorant, and an external additive.
An electrostatic charge image developing toner, wherein the external additive contains inorganic fine particles having a perovskite crystal structure and inorganic layered clay compound fine particles.

  According to the toner for developing an electrostatic charge image of the present invention as described above, the toner is excellent in charging stability and has good charge start-up at the time of replenishment of toner, so that fog hardly occurs and the toner is repeatedly printed. In addition, since the change in the surface state of the toner particles can be reduced, the toner for electrostatic charge image development that can maintain the charging stability of the toner and has excellent printing durability and can be applied to a toner replenishment type image forming apparatus is provided. Is done.

The toner for developing an electrostatic charge image of the present invention is a toner for developing an electrostatic charge image containing a colored resin particle containing a binder resin and a colorant, and an external additive.
The external additive contains inorganic fine particles having a perovskite crystal structure and inorganic layered clay compound fine particles.

  Hereinafter, the electrostatic image developing toner of the present invention (hereinafter, “electrostatic image developing toner” is also simply referred to as “toner”) will be described.

  The toner of the present invention contains colored resin particles containing a binder resin and a colorant, and an external additive, and the colored resin particles may include other charge control agents, release agents, and the like as necessary. The additive 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) a polymerization method and (B) a pulverization method. The toners obtained by these methods are called polymerized toner and pulverized 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.

(A) Polymerization method (1) Preparation step of polymerizable monomer composition First, a polymerizable monomer, a colorant and, if necessary, a charge control agent and other additives are mixed to obtain a polymerizable monomer. A body composition is prepared. The mixing at the time of preparing the polymerizable monomer composition can be performed using, for example, a media type dispersing machine.

  In the present invention, the polymerizable monomer refers to a polymerizable compound. 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; acrylamide Amide compounds such as methacrylamide; 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.

As a part of the polymerizable monomer, it is preferable to use any crosslinkable polymerizable monomer together with the monovinyl monomer in order to improve hot offset. 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 carboxylic acids of polyalcohols such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate Polyesters; Other divinyl compounds such as N, N-divinylaniline and divinyl ether; Compounds having three or more vinyl groups such as trimethylolpropane trimethacrylate and dimethylolpropane tetraacrylate; . These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
In the present invention, it is desirable to use the crosslinkable polymerizable monomer in a proportion of usually 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. .

In addition, when a macromonomer is used as a part of the polymerizable monomer, the balance between the storage stability of the toner and the low-temperature fixability is improved, and therefore any macromonomer can be used together with the monovinyl monomer. preferable. A macromonomer is a reactive oligomer or polymer having a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain and having a number average molecular weight of usually 1,000 to 30,000. Say. The macromonomer preferably gives a polymer having a Tg higher than the glass transition temperature (Tg) of the polymer obtained by polymerizing the monovinyl monomer.
In the present invention, the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the monovinyl monomer. It is desirable to use in.

  In the present invention, a colorant is used, but when a color toner (usually, four types of toners are used: black toner, cyan toner, yellow toner, and magenta toner), a black colorant, a cyan colorant, and a yellow toner are used. A colorant and a magenta colorant can be used, respectively.

  In the present invention, as the black colorant, carbon black, titanium black, and pigments such as magnetic powder such as iron oxide zinc and iron oxide nickel can be used.

  Examples of cyan colorants include compounds such as copper phthalocyanine pigments, derivatives thereof, and anthraquinone pigments. Specifically, C.I. I. Pigment Blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, and 60, etc., with good polymerization stability and coloring power To C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 17: 1, and other copper phthalocyanine pigments are preferred, and C.I. I. Pigment Blue 15: 3 is more preferable.

  As the yellow colorant, for example, azo pigments such as monoazo pigments and disazo pigments, and compounds such as condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, 186, and the like.

  Examples of the magenta colorant include compounds such as azo pigments such as monoazo pigments and disazo pigments, and condensed polycyclic pigments. Specifically, C.I. 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, 251 and C.I. I. Pigment Violet 19 and the like. Since the polymerization stability is good and there is coloring power, C.I. I. Similarly preferred are monoazo pigments such as Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 112, 114, 146, 150, 163, 170, 185, 187, 206, and 207.

  In the present invention, each colorant is preferably used in a proportion of 1 to 10 parts by weight with respect to 100 parts by weight of the monovinyl monomer.

As other additives, a charge control agent is preferably used. As the charge control agent, various positively chargeable or negatively chargeable charge control agents can be used. For example, a metal complex of an organic compound having a carboxyl group or a nitrogen-containing group, a metal-containing dye, and a non-resin charge control agent such as nigrosine; a quaternary ammonium base-containing copolymer, a sulfonic acid group or a sulfonate group-containing copolymer And charge control resins such as carboxyl group or carboxylate group-containing copolymers; Among them, the charge control agent preferably contains a charge control resin because the printing durability of the toner becomes good. Of the charge control agents, a charge control agent that is not a resin and a charge control resin may be used in combination, or the charge control resin may be used alone. More preferably, the charge control resin is used alone. More preferably, a quaternary ammonium base-containing copolymer is used as the charge control resin.
In the present invention, it is desirable to use the charge control agent in a proportion of usually 0.01 to 10 parts by weight, preferably 0.03 to 8 parts by weight, with respect to 100 parts by weight of the monovinyl monomer.

As another additive, it is preferable to add a release agent since the releasability of the toner from the fixing roll during fixing can be improved. The release agent is not particularly limited as long as it is generally used as a toner release agent. Low molecular weight polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; natural waxes such as candelilla, carnauba, rice, wood wax, and jojoba; petroleum waxes such as paraffin, microcrystalline, and petrolatum; montan, ceresin And mineral waxes such as ozokerite; synthetic waxes such as Fischer-Tropsch wax; ester compounds such as behenyl behenate, stearyl stearate, pentaerythritol ester, dipentaerythritol ester; and the like.
In this invention, it is desirable to use a mold release agent in the ratio of 0.1-30 weight part normally with respect to 100 weight part of monovinyl monomers, Preferably it is 1-20 weight part.

It is preferable to use a molecular weight modifier as another additive. Examples of the molecular weight modifier include t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and mercaptans such as 2,2,4,6,6-pentamethylheptane-4-thiol. The molecular weight modifier can be added before the start of polymerization or during the polymerization.
In the present invention, the molecular weight modifier is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the monovinyl monomer.

(2) Suspension step for obtaining a suspension (droplet formation step)
In the present invention, the polymerizable monomer composition obtained as described above is suspended in an aqueous dispersion medium to obtain a suspension (polymerizable monomer composition dispersion). Here, the suspension means that droplets of the polymerizable monomer composition are formed in an aqueous dispersion medium. Dispersion treatment for forming droplets is, for example, an in-line type emulsifying disperser (manufactured by Ebara Manufacturing Co., Ltd., trade name: Ebara Milder), a high-speed emulsifying / dispersing machine (manufactured by Special Machine Industries Co., Ltd., trade name: TK). Etc. can be carried out using a device capable of strong stirring, such as a homomixer MARK II).

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

  In the present invention, the aqueous dispersion 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;

  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.

  The said dispersion stabilizer can be used 1 type or in combination of 2 or more types. The amount of the dispersion stabilizer added is preferably 0.1 to 20 parts by weight and more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. Further, the addition amount of the dispersion stabilizer is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the aqueous dispersion medium.

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 dispersion 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 step As described above, the suspension containing droplets of the polymerizable monomer composition obtained in the suspension step (droplet formation step) is heated to initiate polymerization. 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 obtained by polymerization of the polymerizable monomer composition may be used as a toner by adding an external additive as it is, but the colored resin particles are used as a core layer, and a shell different from the core layer on the outside. It is preferable to use so-called core-shell type (or “capsule type”) colored resin particles obtained by forming a layer. 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 dispersion medium in which colored resin particles obtained by the polymerization method are dispersed. By doing so, 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 preferably repeated several times as necessary.

  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.

(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, and, if necessary, additives such as 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, etc. 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 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. As the colorant used in the pulverization method, and additives such as a release agent and a charge control agent used as desired, those mentioned 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.
(5) Colored resin particles

  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 core-shell type and non-core type.)

From the viewpoint of image reproducibility, the volume average particle diameter (Dv) of the colored resin particles of the present invention is preferably 5 to 10 μm, and more preferably 6.5 to 10 μm.
On the other hand, when the volume average particle diameter (Dv) of the colored resin particles of the present invention is less than the above range, fog may easily occur. Moreover, when the volume average particle diameter (Dv) of the colored resin particles of the present invention exceeds the above range, the resolution of the image may be lowered.

In addition, the particle size distribution (Dv / Dp), which is the ratio of the volume average particle size (Dv) and the number average particle size (Dp), of the colored resin particles of the present invention is 1.0 to It is preferably 1.3, more preferably 1.0 to 1.25, and even more preferably 1.0 to 1.2.
On the other hand, when the particle size distribution (Dv / Dp) of the colored resin particles of the present invention exceeds the above range, the chargeability of the toner may not be uniform, and fog may be easily generated.
The volume average particle diameter (Dv) and the number average particle diameter (Dp) can be measured using, for example, a multisizer (manufactured by Beckman Coulter).

The average circularity of the colored resin particles of the present invention is preferably 0.950 to 0.995, more preferably 0.960 to 0.995, and still more preferably, from the viewpoint of image reproducibility. 0.970 to 0.995.
On the other hand, when the average circularity of the colored resin particles of the present invention is less than the above range, the transferability may be lowered and the image reproducibility may be lowered. Moreover, when the average circularity of the colored resin particles of the present invention exceeds the above range, the production tends to be difficult.

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 circumference of the projected image of the particle. Further, 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 toner. The average circularity is a value obtained when the toner is perfectly spherical. 1 is shown in this case, and the value becomes smaller as the surface shape of the toner becomes more complicated. For the average circularity, the circularity (Ci) of each particle measured for a particle group having a circle-equivalent diameter of 0.4 μm or more was obtained for each of n particles from the following calculation formula 1, and then averaged from the following calculation formula 2. Obtain the circularity (Ca).
Formula 1:
Circularity (Ci) = perimeter of circle equal to projected area of particle / perimeter of projected particle image

In the above calculation formula 2, fi is the frequency of particles having a circularity (Ci).
The circularity and the average circularity can be measured using a flow type particle image analyzer “FPIA-2000”, “FPIA-2100”, “FPIA-3000”, etc. manufactured by Sysmex Corporation.

(6) External Addition Step Inorganic fine particles having a perovskite crystal structure as defined in the present invention as an external additive to the colored resin particles obtained by the above-described (A) polymerization method or (B) pulverization method, and inorganic Layered clay compound fine particles are mixed (added externally).

  The inorganic fine particles having a perovskite crystal structure and the inorganic layered clay compound fine particles used in the present invention are mixed and stirred together with the colored resin particles using a high-speed stirrer to coat the surface of the colored resin particles with the external additive. be able to. Examples of the high-speed stirrer include Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name: manufactured by Kawada Seisakusho Co., Ltd.), Q mixer (: trade name, manufactured by Mitsui Mining Co., Ltd.), mechano-fusion system ( : Trade name, manufactured by Hosokawa Micron Co., Ltd.), mechano mill (: trade name, manufactured by Okada Seiko Co., Ltd.) and the like.

  As in the present invention, when two or more kinds of external additives are used in combination, the colored resin particles and the total external additive may be added to the high-speed stirrer and externally added. It is preferable to perform external addition by adding only an external additive having a large particle size in a high-speed stirrer and then adding an external additive having a smaller particle size.

  Examples of the inorganic fine particles having a perovskite crystal structure used in the present invention include strontium titanate, barium titanate, magnesium titanate, and calcium titanate. Further, strontium titanate is more preferable because the change in the surface state of the toner particles is small and the fluidity of the toner can be stably maintained.

The number average primary particle size of the inorganic fine particles having a perovskite crystal structure used in the present invention is preferably 10 to 200 nm because printing durability is good and fogging during toner replenishment can be suppressed. The thickness is preferably 10 to 120 nm, more preferably 10 to 80 nm.
On the other hand, when the number average primary particle diameter of the inorganic fine particles having a perovskite crystal structure used in the present invention is less than the above range, the toner particles are easily embedded in the surface of the toner particles, and the printing durability may be reduced. is there. In addition, when the number average primary particle size of the inorganic fine particles having a perovskite crystal structure used in the present invention exceeds the above range, the fluidity of the toner may be deteriorated and fogging may occur during toner replenishment. .

The degree of hydrophobicity of the inorganic fine particles having a perovskite crystal structure used in the present invention is preferably 10% or less, and more preferably 8% or less.
If the degree of hydrophobicity of the inorganic fine particles having a perovskite crystal structure used in the present invention exceeds the above range, fog may occur during toner replenishment.

The degree of hydrophobicity can be measured, for example, using the methanol method by the following method.
A predetermined weight of inorganic fine particles as a sample is weighed, a predetermined volume of pure water is added thereto, and methanol is added below the liquid level. The point at which the sample is no longer recognized on the liquid surface is taken as the end point, and the degree of hydrophobicity is calculated by the following formula 3.
Formula 3:
Hydrophobicity (%) = (X / (Y + X)) × 100
X: Methanol usage (ml) Y: Pure water usage (ml)

  The inorganic fine particles having a perovskite crystal structure used in the present invention can adjust the degree of hydrophobicity by subjecting the surface of the particles to a hydrophobic treatment. As the hydrophobizing treatment, a conventionally known method can be used. For example, a surface modifying agent such as a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, or silicone oil can be obtained by a wet treatment method or a dry treatment method. The method of processing is mentioned.

The amount of inorganic fine particles having a perovskite crystal structure used in the present invention is preferably 0.1 to 0.5 parts by weight, more preferably 0.1 to 100 parts by weight of the colored resin particles. ˜0.35 parts by weight, more preferably 0.12 to 0.3 parts by weight.
On the other hand, when the amount of the inorganic fine particles having a perovskite crystal structure used in the present invention is less than the above range, the fog at the time of toner replenishment may not be suppressed. Further, when the amount of inorganic fine particles having a perovskite crystal structure used in the present invention exceeds the above range, printing durability may be lowered.

The inorganic layered clay compound fine particles used in the present invention preferably have quaternary ammonium ions intercalated between the layers from the viewpoint of charging stability and printing durability.
Examples of the inorganic layered clay compound fine particles used in the present invention include, for example, kaolin groups such as kaolinite, dickite, halloysite, and lizarsite; smectite groups such as montmorillonite, hydelite, nontronite, hectorite, and saponite; phlogopite, Mica group such as biotite, muscovite, paragonite, sericite; chlorite group such as clinochlore, chamosite, penantite, dombasite; talc-pyrophyllite such as talc, willemsite, kerolite, pyrophyllite Group; and the like. 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 types 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

  Examples of the cation constituting the quaternary ammonium salt used for intercalation in the present invention include a tetraalkylammonium cation, an ammonium cation having a benzyl group and an alkyl group, and a pyridinium cation. In addition, examples of the anion constituting the quaternary ammonium salt include hydroxide ion, halogen ion (fluorine ion, chlorine ion, bromine ion and iodine ion), nitrate ion, nitrite ion, methosulphate ion, and the like. Is preferred.

  As said tetraalkylammonium cation, the ammonium cation which consists of a C1-C22 alkyl group etc. 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 the 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, and examples of the quaternary ammonium salt comprising these include benzyllauryldimethyl. Ammonium chloride (benzalkonium chloride), benzyldimethyloctylammonium methosulfate and the like can be mentioned.

  As the pyridinium cation, a pyridinium cation having an alkyl group having 8 to 22 carbon atoms can be used. Examples of the quaternary ammonium salt composed of these include N-cetylpyridinium chloride, N-oleylpyridinium chloride, and N-lauryl. Examples thereof include pyridinium chloride and N-lauryl pyridinium methosulfate.

  The inorganic layered clay compound fine particles used in the present invention may be hydrophobized. 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 the silane coupling agent 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. .

  In the present invention, as a method for hydrophobizing the inorganic layered clay compound fine particles, 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 size of the inorganic layered clay compound fine particles used in the present invention is preferably 0.01 to 5 μm, more preferably 0.01 to 3 μm, and still more preferably 0.01 to 1 μm. .
On the other hand, when the number average primary particle size of the inorganic layered clay compound fine particles used in the present invention is less than the above range, the printing durability may be lowered.
In addition, when the number average primary particle size of the inorganic layered clay compound fine particles used in the present invention exceeds the above range, the image reproducibility may deteriorate.

The amount of inorganic layered clay compound fine particles used in the present invention is preferably 0.05 to 3 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the colored resin particles. is there.
On the other hand, when the amount of the inorganic layered clay compound fine particles used in the present invention is less than the above range, the printing durability may be lowered. Further, when the amount of the inorganic layered clay compound fine particles used in the present invention exceeds the above range, the image reproducibility may be lowered.

  In the present invention, in addition to the external additive, silica fine particles having a number average primary particle size of 5 to 18 nm (hereinafter referred to as “silica fine particles (A)”), and a number average primary particle size of 20 to 200 nm. Silica fine particles (hereinafter referred to as “silica fine particles (B)”) are preferably contained.

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

  The amount of the silica fine particles (A) added is preferably 0.01 to 4 parts by weight, more preferably 0.05 to 2 parts by weight, and still more preferably 100 parts by weight of the colored resin particles. 0.05 to 1 part by weight. The addition amount of the silica fine particles (B) is preferably 0.01 to 4 parts by weight, more preferably 0.05 to 2 parts by weight, further preferably 100 parts by weight of the colored resin particles. Is 0.05 to 1 part by weight.

(7) Image forming apparatus Since the inorganic fine particles having a perovskite crystal structure used as an external additive have a polishing effect, the toner of the present invention is polished without providing a cleaner in the image forming apparatus. Therefore, it is considered that the transfer efficiency of the toner can be improved.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited only to these examples. Parts and% are based on weight unless otherwise specified.
The test methods performed in the examples and comparative examples are as follows.

(1) Number average primary particle size of external additives The number average primary particle size of external additives is obtained by taking an electron micrograph of each particle, and using the image processing analysis device (trade name: Luzex IID, manufactured by Nireco). ), The equivalent circle diameter corresponding to the projected area of the particles was calculated under the conditions of the area ratio of the particles to the frame area: 2% at the maximum and the total number of processed particles: 100, and the arithmetic average value was obtained.

(2) Degree of hydrophobicity of external additive The degree of hydrophobicity was determined according to the methanol method shown below.
0.2 g of the external additive to be measured was weighed into a 500 mL beaker, 50 mL of pure water was added, and methanol was added below the liquid level while stirring with a magnetic stirrer. The point at which no sample (fine particles) was observed on the liquid surface was taken as the end point, and the degree of hydrophobicity was calculated by the following formula 4.
Formula 4:
Hydrophobicity (%) = (X / (50 + X)) × 100
X: Methanol consumption (mL)

(3) Measurement of particle diameter of colored resin particles (3-1) Volume average particle diameter (Dv), number average particle diameter (Dp)
For the measurement of the volume average particle diameter (Dv) and the number average particle diameter (Dp) of the colored resin particles, a particle diameter measuring machine (Beckman Coulter, trade name: Multisizer) was used. The measurement with this multisizer was performed under the conditions of an aperture diameter: 100 μm, a medium: Isoton II, and a number of measured particles: 100,000. Specifically, 0.1 g of colored resin particles was placed in a beaker, and 0.1 ml of an alkylbenzene sulfonic acid aqueous solution (manufactured by Fuji Film Co., Ltd., trade name: Drywell) was further added as a dispersant. Further, 20 ml of Isoton II was added to the beaker and dispersed with a 20 W ultrasonic disperser for 3 minutes, and then the measurement with the particle size measuring apparatus was performed.

(3-2) Average circularity Into a container, 10 ml of ion exchange water is put in advance, 0.02 g of a surfactant (alkylbenzenesulfonic acid) as a dispersant is added, and 0.02 g of colored resin particles is further added. Then, the dispersion treatment was performed with an ultrasonic disperser at 60 W for 3 minutes. The concentration of the colored resin particles at the time of measurement is adjusted to be 3,000 to 10,000 particles / μl, and 1,000 to 10,000 colored resin particles having an equivalent circle diameter of 0.4 μm or more are flow-type particle images. Measurement was performed using an analyzer (trade name: FPIA-2100, manufactured by Simex Corporation). The average circularity was determined from the measured value.
The circularity is shown in the following calculation formula 1, and the average circularity is an average of the circularity.
Formula 1:
(Circularity) = (Perimeter of circle equal to projected area of particle) / (Perimeter of particle projection image)

(4) Printing test (4-1) Printing durability (NN environment)
A commercially available non-magnetic one-component developing type printer HL-5040 printer (manufactured by Brother Kogyo Co., Ltd.) was used to set printing paper and put toner in the developing device. After being left 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 using a reflection type image densitometer (trade name: RD918, manufactured by Macbeth). Furthermore, after that, white solid printing (printing 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 developed photoconductor 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 the fog value (%). Smaller values indicate better fogging.
The number of continuous prints capable of maintaining an image quality with a print density of 1.3 or more and a fog value of 3 or less was examined, and the number was determined as the durable print number in the NN environment.

(4-2) Fog immediately after toner replenishment After completion of the print durability test in (4-1), 30 g of the remaining toner in the developing device is left, and 100 g of new toner is further replenished to perform white solid printing (print density 0%). The printer is stopped in the middle of white solid printing, and the toner in the non-image area on the developed photoreceptor is adhered to the adhesive tape (manufactured by Sumitomo 3M, product name: Scotch Mending Tape 810-3-18). And pasted it on the 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 the fog value (%). Smaller values indicate better fogging.
Immediately after toner replenishment, the fog value is 3 or more, but the fog value gradually decreases as printing is repeated. When the fog value became 3 or less by printing, the number of continuous prints was examined and set as the fog disappearing number at the time of replenishment.

(Production Example 1: Inorganic layered clay compound fine particles A)
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.). The solid content obtained by filtration was repeatedly washed with deionized water, then dehydrated, dried in a vacuum dryer at 60 ° C. for 24 hours, and an inorganic layered form in which dimethyl distearyl ammonium chloride was intercalated between layers. Clay compound fine particles A were obtained.

(Production Example 2: Inorganic layered clay compound fine particles B)
The obtained inorganic layered clay compound fine particles A were hydrophobized by the following method to obtain inorganic layered clay compound fine particles B.
After putting 100 g of inorganic layered clay compound fine particles A in 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 is introduced in association with nitrogen, and the inorganic layered clay compound fine particles A and the gasified amino group-containing silane coupling agent are brought into contact with each other to perform a hydrophobization treatment. Fine particles B were obtained.

(Production Example 3: Inorganic layered clay compound fine particles C)
150 parts of bentonite having a number average primary particle size of 5 μm were dispersed in 1,500 parts of ion-exchanged water, and then heated to 80 ° C., and then a high-speed emulsification disperser (trade name: T.K. K. homomixer MARK type II) and stirred for 1 hour. The solid content obtained by filtration was repeatedly washed with deionized water, dehydrated, and dried in a vacuum dryer at 60 ° C. for 24 hours to obtain inorganic layered clay compound fine particles C.

(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 polymerizable monomer, and t-dodecyl mercaptan as a molecular weight regulator. After stirring and mixing 9 parts and 0.25 part of a polymethacrylic acid ester macromonomer (manufactured by Toa Gosei Chemical Co., Ltd., trade name: AA6) as a macromonomer, a media-type wet grinder (manufactured by Turbo Industry Co., Name: OB bead mill). 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.

  On the other hand, at room temperature, an aqueous solution obtained by dissolving 10.2 parts of magnesium chloride in 250 parts of ion-exchanged water and an aqueous solution prepared by dissolving 6.2 parts of sodium hydroxide in 50 parts of ion-exchanged water were gradually added with stirring. Then, a magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid) dispersion was prepared.

  The polymerizable monomer composition is added to the magnesium hydroxide colloidal dispersion obtained as described above, stirred, and t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd.) as a polymerization initiator. After the addition of 6 parts of product, trade 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 when the polymerization conversion rate reaches almost 100%, and ion exchange 2,2′-Azobis (2-methyl-N- (2-hydroxyethyl) -propionamide) dissolved in 20 parts of water) (polymerization initiator for shell, manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086) 0.3 part was 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 resulting aqueous dispersion of colored resin particles, sulfuric acid is added to adjust the pH to 6.5 or less, acid washing is performed, and after dehydration by filtration, 500 parts of ion-exchanged water is added again to make a slurry again. Water washing was performed. Thereafter, similarly, dehydration and washing with water were repeated several times, and after dehydration by filtration, they were put in a container of a dryer and dried at 45 ° C. for 48 hours to obtain dried colored resin particles.
The resulting colored resin particles had a volume average particle size (Dv) of 9.7 μm, a particle size distribution (Dv / Dp) of 1.15, and an average circularity of 0.990.

Hydrophobized silica fine particles (A) (manufactured by Clariant, trade name: HDK2150, number average primary particle size: 14 nm) 0.8 parts were hydrophobized to 100 parts of the colored resin particles obtained as described above. Silica fine particles (B) (manufactured by Nippon Aerosil Co., Ltd., trade name: NA50Y, number average primary particle size: 50 nm) 1 part, strontium titanate fine particles (trade name: manufactured by Titanium Industry Co., Ltd.) which are inorganic fine particles having a perovskite crystal structure SW-350) 0.2 part, 0.2 parts of inorganic layered clay compound fine particles A prepared in Production Example 1 were added, and the mixture was stirred for 5 minutes using a high-speed stirrer (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.). The toner was mixed at a speed of 30 m / s and externally added to prepare a toner for developing a non-magnetic one-component electrostatic charge image of Example 1 and used for the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

(Example 2)
The type of inorganic fine particles having a perovskite crystal structure was changed to strontium titanate (product name: SW360, manufactured by Titanium Industry Co., Ltd.), the amount of inorganic fine particles having a perovskite crystal structure was changed to 0.15 parts, and A toner of Example 2 was produced in the same manner as in Example 1 except that the type of the inorganic layered clay compound fine particles was changed to the inorganic layered clay compound fine particles B produced in Production Example 2, and subjected to the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

(Example 3)
The kind of inorganic fine particles having a perovskite crystal structure was changed to barium titanate (trade name: BT-HP100, manufactured by Kyoritsu Material Co., Ltd.), and the amount of inorganic fine particles having a perovskite crystal structure was changed to 0.1 part. Except for this, the toner of Example 3 was produced in the same manner as in Example 1, and was subjected to the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

Example 4
Inorganic layered clay compound prepared in Production Example 3 by changing the type of inorganic fine particles having a perovskite crystal structure to barium titanate (trade name: BT-HP9DX, manufactured by Kyoritsu Materials Co., Ltd.) A toner of Example 4 was produced in the same manner as in Example 1 except that it was changed to the fine particles C, and used for the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

(Comparative Example 1)
A toner of Comparative Example 1 was produced in the same manner as in Example 1 except that the inorganic fine particles having a perovskite crystal structure were not added, and were subjected to the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

(Comparative Example 2)
A toner of Comparative Example 2 was produced in the same manner as in Example 1 except that the inorganic layered clay compound fine particles were not added, and was subjected to the test.
The image formation of the obtained toner was performed using an image forming apparatus without a cleaner.

(result)
Table 1 shows the test results of the toners produced in each Example and Comparative Example.

(Summary of results)
From the test results described in Table 1, the following can be understood.
The toner of Comparative Example 1 had relatively good printing durability due to the use of only the inorganic layered clay compound fine particles defined in the present invention as an external additive, but in printing immediately after toner replenishment. A fog has occurred. The toner of Comparative Example 2 was poor in printing durability although printing was good immediately after toner replenishment due to the use of only inorganic fine particles defined in the present invention as an external additive.
On the other hand, the toners of Examples 1 to 4 are caused by the use of both the inorganic fine particles and the inorganic layered clay compound fine particles defined in the present invention, and both in the printing immediately after the toner replenishment and after the durable printing. The toner was free from fogging and excellent in printing performance.

Claims (9)

In the toner for developing an electrostatic charge image, which contains a colored resin particle comprising a binder resin and a colorant, and an external additive,
An electrostatic charge image developing toner, wherein the external additive contains inorganic fine particles having a perovskite type crystal structure and inorganic layered clay compound fine particles.   The colored resin particles have a volume average particle diameter (Dv) of 5 to 10 μm and a ratio (Dv / Dp) of the volume average particle diameter (Dv) to the number average particle diameter (Dp) of 1.0 to 1. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the toner has an average circularity of 0.950 to 0.995.   3. The electrostatic image developing toner according to claim 1, wherein the inorganic fine particles having a perovskite crystal structure are selected from strontium titanate, barium titanate, magnesium titanate, and calcium titanate.   The electrostatic image developing toner according to claim 1, wherein the inorganic fine particles having a perovskite crystal structure have a hydrophobicity of 10% or less.   5. The electrostatic image developing toner according to claim 1, wherein the inorganic fine particles having a perovskite crystal structure have a number average primary particle size of 10 to 200 nm.   The content of the inorganic fine particles having the perovskite crystal structure is 0.1 to 0.5 parts by weight with respect to 100 parts by weight of the colored resin particles. The toner for developing an electrostatic charge image according to 1.   7. The electrostatic image developing toner according to claim 1, wherein the inorganic layered clay compound fine particles have quaternary ammonium ions intercalated between the layers.   The electrostatic charge image developing toner according to claim 1, wherein the inorganic layered clay compound fine particles have a number average primary particle size of 0.01 to 5 μm.   An image forming method using the electrostatic image developing toner according to claim 1 in an image forming apparatus without a cleaner.