JP2017219823A - Toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development excellent in cleanability of a surface of a photoreceptor.SOLUTION: In a toner including toner base particles and an external additive, both positively-charged lubricant particles and negatively-charged lubricant particles are made to be included in the toner as components of the external additive to solve the problem. That is, the present invention is a toner for electrostatic charge image development including toner base particles and an external additive, and including both positively-charged lubricant particles and negatively-charged lubricant particles as components of the external additive.SELECTED DRAWING: None

Description

  The present invention relates to a toner for developing an electrostatic image.

  The electrophotographic image forming method can obtain high-quality printed matter (images, prints, etc.) at a high speed, so various printers, copiers, facsimiles, etc. (hereinafter these electrophotographic methods are summarized) Are also widely used. In this image forming method, an electrostatic charge image is formed by performing exposure according to a desired image on the surface of a charged photoreceptor, and then the electrostatic charge image developing toner (hereinafter simply referred to as an electrostatic charge image developing toner). (Also referred to as “toner”) is electrostatically attached to form a toner image on the surface of the photoconductor, and then this image is transferred to a recording medium such as paper, thereby forming a desired image on the recording medium. An image is formed.

  The image formed by the toner formed on the recording medium is in a powder form immediately after the image is formed, but is fixed on the recording medium through a fixing process of being heated and pressurized by a fixing roller. At this time, a resin component (referred to as a binder resin or a binder) and a release agent (wax) contained in the toner are once melted by heat, so that the powdered toner becomes a liquid melt, which is then By cooling, a film adhered to the surface of the recording medium is formed. This film corresponds to an image, printing, or the like fixed on a recording medium.

  Such image forming methods are classified into a one-component developing method and a two-component developing method depending on a method of charging toner particles for developing an electrostatic image. In the two-component development method, the toner particles and the carrier particles are agitated in the toner box, thereby causing friction between them and charging the toner particles. In the one-component development method, the toner particles are charged by friction between a charging blade provided near the outlet of the toner box and the toner particles without using carrier particles. Both methods are common in that development is performed by attaching charged toner to a photoreceptor on which an electrostatic charge image is formed. Generally, charged toner adheres to a portion of the surface of the photoconductor that has been uncharged by light irradiation, and toner does not adhere to a portion of the surface of the photoconductor that remains charged due to electrostatic repulsion. Development is performed at. The toner image formed on the surface of the photoreceptor by development is transferred to a recording medium such as paper.

  After the toner image formed on the surface of the photoreceptor is transferred to the recording medium, cleaning is performed to remove the toner remaining on the surface of the photoreceptor without being transferred using an elastic cleaning blade. . However, for example, after a long period of use, toner that has not been removed tends to remain on the surface of the photoconductor after cleaning due to deterioration of the cleaning member, and the photoconductor and the charging roller in contact therewith ( Filming may occur in which film-like toner adheres to the surface of (PCR). In this case, the charging of the photosensitive member becomes unstable, or contamination due to partial peeling of the film-like toner occurs, which causes image defects and an increase in the amount of toner used.

  From such a background, Patent Document 1 proposes that an inorganic layered substance is internally added in the toner base particles to suppress contamination of the photoreceptor, the developing blade, the cleaning blade, and the like even when used for a long time. Has been. Patent Document 2 discloses that 0.01 to 1.0 parts by mass of a compound having a plate-like shape is externally added to 100 parts by mass of toner particles, so that negative ghosts can be suppressed while keeping the toner tap density small. It has been proposed to do. Patent Document 3 proposes a one-component toner characterized by externally adding boron nitride having an average primary particle size of 1 to 40 μm. In these toners, particles having lubricity, that is, lubricant particles are added, and the lubricant particles adhere to the surface of the photoconductor to impart lubricity, so that the rotating photoconductor This is considered to help maintain the contact state of the cleaning blade on the surface and reduce the toner remaining on the surface of the photoreceptor after cleaning.

Japanese Patent No. 4863107 Japanese Patent No. 3457729 Japanese Patent No. 5598242

  As described above, by adding lubricant particles to the toner, the remaining toner on the surface of the photoreceptor is considerably improved. However, according to the studies by the present inventors, such an effect can be obtained satisfactorily if the image to be formed has a medium line drawing rate, but the image has a low line drawing rate, or conversely, If the image has a large linearity, it still tends to cause problems such as filming due to toner remaining on the surface of the photoreceptor and PCR contamination.

  The present invention has been made in view of the above situation, and an object thereof is to provide a toner for developing an electrostatic charge image that is excellent in the cleanability of the surface of a photoreceptor.

  As a result of intensive studies in order to solve the above problems, the present inventors have determined that both positively charged lubricant particles and negatively charged lubricant particles are used in toner containing toner base particles and external additives. It has been found that the above-mentioned problems can be solved by including them as components of external additives. The present invention has been made based on the above findings, and specifically provides the following.

  The present invention includes toner base particles and an external additive, and includes both positively charged lubricant particles and negatively charged lubricant particles as components of the external additive, respectively. Toner.

  The positively chargeable lubricant particles are at least one selected from the group consisting of fatty acid metal salts, and the negatively chargeable lubricant particles are boron nitride, polytetrafluoroethylene, polyvinylidene fluoride, polymethacrylic acid. It is preferably at least one selected from the group consisting of methyl acid and silicone.

  The content of the positively chargeable lubricant particles is 0.01 to 0.5 parts by weight with respect to 100 parts by weight of the toner base particles, and the content of the negatively chargeable lubricant particles is the toner. It is preferable that it is 0.01-0.5 mass part with respect to 100 mass parts of mother particles.

  The negatively chargeable lubricant particles preferably contain boron nitride.

  The positively chargeable lubricant particles preferably include zinc stearate.

  According to the present invention, there is provided an electrostatic image developing toner excellent in the cleaning property of the photoreceptor surface.

  Hereinafter, an embodiment of the toner for developing an electrostatic charge image of the present invention will be described.

  The electrostatic image developing toner of the present invention (as described above, also simply referred to as “toner”) may be a two-component toner used in an electrophotographic image forming method and used with a carrier. One-component toner that does not use a carrier may be used. The toner of the present invention comprises toner base particles and an external additive. Hereinafter, each component constituting the toner of the present invention will be described.

<Toner base particles>
The toner base particles are the main components of the toner containing a binder resin, a colorant, and a release agent. The toner base particles are mixed with the external additive to form a toner. First, each component constituting the toner base particles will be described.

[Binder resin]
The binder resin is also called a binder and is one of the components contained in the toner base particles. The binder resin disperses the colorant contained in the toner base particles and solidifies after being melted on the surface of the recording medium by the heat of the fixing roller in the fixing process during printing, thereby fixing the colorant on the surface of the recording medium. Let

  The binder resin used in the toner of the present invention is not particularly limited, and conventionally known resins can be exemplified. Examples of such a binder resin include styrene copolymers such as polystyrene, styrene-methyl acrylate copolymer, styrene-acrylonitrile copolymer, and resin materials such as polyester and epoxy resin. These binder resins can be used alone or in combination of two or more. Among these binder resins, polyester can be preferably exemplified from the viewpoint of being easily colored and obtaining a clear color toner.

  The polyester is obtained by polymerizing a monomer composition composed of a dihydric or higher polyhydric alcohol and a polybasic acid.

  Examples of the dihydric alcohol used for polyester polymerization include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1 Diols such as 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A alkylene such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A An oxide adduct etc. can be mentioned.

  Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4. -Butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxy Mention may be made of methylbenzene and the like.

  Examples of the divalent polybasic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, and anhydrides of these acids. .

  Examples of the tribasic or higher polybasic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 2,5,7-naphthalenetricarboxylic acid. Acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2, Examples include 7,8-octanetetracarboxylic acid and anhydrides of these acids.

  The addition amount of the binder resin in the toner base particles may be appropriately set in consideration of the performance required for the toner, but as an example, it is 65 to 95 parts by weight in 100 parts by weight of the toner base particles. Can be mentioned.

[Colorant]
The colorant gives coloring power to the toner and is one of the components contained in the toner base particles. The colorant used in the toner of the present invention is not particularly limited, and various conventionally known pigments can be exemplified.

  Specifically, carbon black, black magnetic powder, etc. are exemplified as the black colorant, and copper phthalocyanine, methylene blue, Victoria blue, etc. are exemplified as the material of the cyan colorant, and the magenta colorant. Examples include rhodamine dyes, dimethylquinacridone, dichloroquinacridone, and carmine red. Examples of yellow colorants include benzidine yellow, chrome yellow, naphthol yellow, and disazo yellow. In addition, a colorant according to a desired color can be appropriately selected and used.

  The addition amount of the colorant in the toner base particles may be appropriately set in consideration of performance such as coloring power required for the toner, etc. As an example, 1 to 15 masses per 100 mass parts of the toner base particles. Part. Various master batches in which a high-concentration pigment is dispersed in advance in the resin are commercially available, and may be purchased and used as a colorant. In this case, the usage amount may be determined in consideration of the concentration of the pigment contained in the master batch so that the concentration of the pigment contained in the toner base particles is in the above range.

[Release agent]
The release agent is also called a wax and is one of the components contained in the toner base particles. The release agent is used to improve the release property between the fixing roller and the printing surface (more precisely, toner existing on the surface of a recording medium such as paper) in the fixing process during printing. .

  As the release agent, those usually used as a release agent for toner base particles can be used without particular limitation. Examples of such a release agent include polyolefin waxes such as polyethylene and polypropylene, hydrocarbon waxes such as Fischer-Tropsch wax, microcrystalline wax, and paraffin wax, pentaerythritol behenate, behenyl behenate, behenyl citrate, Examples include ester waxes such as montan ester wax, carnauba wax, rice wax, and Fischer tropish wax. These release agents can be used alone or in combination of two or more. Among these release agents, hydrocarbon waxes can be preferably exemplified.

  The amount of the release agent added to the toner base particles may be appropriately set in consideration of the performance required for the toner, but as an example, it is 2 to 12 parts by weight in 100 parts by weight of the toner base particles. Can be mentioned. When the addition amount of the release agent is within this range, good releasability between the fixing roller and the printing surface can be obtained in the fixing process during printing (that is, image formation or printing) and the toner can be separated from the toner base particles. Various troubles such as charging failure and filming due to leaching of the mold can be suppressed. The addition amount of the release agent in the toner base particles is more preferably 2 to 10 parts by weight, and further preferably 3.5 to 8 parts by weight with respect to 100 parts by weight of the toner base particles.

[Preparation of toner base particles]
Toner base particles are prepared from the above components. At this time, other components may be added according to various required aptitudes. In preparing the toner base particles, first, the various components described above are mixed, and then these components are kneaded while being heated to a temperature equal to or higher than the melting temperature of the binder resin. In kneading, a kneader such as a twin-screw extruder or a three-roll mill can be used. The kneaded material thus obtained is cooled and solidified, then pulverized by a pulverizer, and then classified to obtain toner base particles. There is no restriction | limiting in particular as a grinder used for the grinding | pulverization of a kneaded material, For example, a jet mill, a turbo mill, a rotor-type grinder etc. can be mentioned. The volume median particle size (D50) of the toner base particles after pulverization and classification is preferably exemplified by 4 to 10 μm, more preferably 5 to 9 μm.

  The volume median particle diameter (D50) is also called a volume-based median diameter, and the total volume of particles whose diameter is smaller than this value and the total volume of particles whose diameter is larger than this value are the total volume. Each value represents 50% of the total volume. The volume median particle size (D50) can be calculated by performing particle size distribution measurement. An example of such a particle size distribution measuring apparatus is “Multisizer 3” manufactured by Beckman Coulter.

<External additive>
The external additive is a particle component constituting the toner together with the toner base particles by being added to the toner base particles. The present invention is characterized by including both positively charged lubricant particles and negatively charged lubricant particles as components of the external additive.

  As already described, the lubricant particles adhere to the surface of the photoreceptor and impart lubricity, thereby helping to maintain the contact state of the cleaning blade on the surface of the rotating photoreceptor, and the surface of the photoreceptor after cleaning. It has the function of reducing the remaining toner. For this reason, it is important that an appropriate amount of lubricant particles be present on the surface of the photoconductor. If the lubricant particles on the surface of the photoconductor are insufficient for any reason, the toner that has not been transferred to the recording medium is transferred to the surface of the photoconductor. In this case, the surface of the photosensitive member is soiled as printing is performed, and filming is caused.

  On the other hand, if the amount of lubricant particles added to the toner is simply increased in order to increase the amount of lubricant particles supplied to the surface of the photoconductor, the amount of lubricant particles will be excessive, which will result in lubricant particles and recording. The toner that has not been transferred to the medium slips through the cleaning blade and is not sufficiently removed, which tends to cause streaking of the image due to contamination of the PCR.

  As described above, even if the number of lubricant particles on the surface of the photoconductor is insufficient or excessive, problems with cleaning of the surface of the photoconductor tend to occur, and it is important that an appropriate amount of lubricant particles be present on the surface of the photoconductor. is there. For this reason, in order to make the amount of lubricant particles present on the photoreceptor surface appropriate, in the toner manufactured by each manufacturer, the amount of lubricant particles contained in the toner is adjusted to an appropriate amount. This is the current situation.

  However, even if the amount of lubricant particles contained in the toner is appropriately adjusted, continuous printing of a pattern with a large image area ratio may cause filming as seen when the lubricant particles are insufficient. . On the other hand, if the amount of lubricant particles added to the toner is increased so as not to run out of lubricant particles even when printing such a pattern, the lubricant particles on the surface of the photoreceptor become excessive and PCR stains occur. Leads to results. In the study for improving such a phenomenon, the present inventors paid particular attention to the charging of the lubricant particles, and by using a combination of positively chargeable lubricant particles and negatively chargeable lubricant particles, such a problem is caused. It was found that can be solved. Next, the relationship between the charging of the lubricant particles and the excess or deficiency of the lubricant particles on the photoreceptor surface will be described. For ease of explanation, the following explanation will be given by taking a case of using a negatively charged printer as an example. However, even in the case of a positively charged printer, the principle is just because the sign of the charge is opposite. It should be noted that the present invention is applied in exactly the same manner.

  In a negatively charged printer, the entire surface of the photoreceptor surface is once negatively charged, and thereafter, a latent image is formed by removing the charge at a portion where an image is formed. The toner base particles are negatively charged due to friction between the carrier and the charging blade, and do not adhere to the negatively charged non-image portion due to electrostatic repulsion but adhere to the uncharged image portion. On the other hand, the lubricant particles added as an external additive are also charged by friction between the carrier and the charging blade, and are charged positively or negatively depending on the chemical composition of the lubricant particles. For example, zinc stearate, a kind of lubricant particles, is positively charged, and when used as lubricant particles, it acts more easily on negatively charged non-image areas than on uncharged image areas. It will be. For this reason, lubricant particles on the surface of the photoreceptor are insufficient in the high image area ratio portion, and filming is likely to occur. As described above, if the amount of the lubricant particles added to the toner is increased in order to avoid this, the lubricant particles become excessive at the low image area ratio and the PCR stains are likely to occur. is there.

  In order to solve such a problem, in the present invention, as described above, the positively charged lubricant particles and the negatively charged lubricant particles are combined and included in the external additive. In this way, positively charged lubricant particles act on the negatively charged non-image portion, while negatively charged lubricant particles electrostatically repel the non-image portion on the uncharged image portion. Will adhere. As a result, the lubricant particles are supplied to the surface of the photoconductor without excess or deficiency without being affected by the image line rate of the printed image, and the occurrence of the above problems is suppressed.

  In general, when positively charged lubricant particles and negatively charged lubricant particles are used in combination, it is expected that the mutual charge is canceled and the desired effect cannot be obtained. According to the above, it is unexpectedly confirmed that the expected effect can be obtained by combining the two. Hereinafter, each component used as an external additive is demonstrated.

  The lubricant particles are components added for the purpose of enhancing the slidability by adhering to the surface of the photoreceptor, and are not particularly limited as long as the particles can impart the slidability. As such particles, those conventionally used in the field of toner can be used without particular limitation. In the present invention, it is important to use positively charged lubricant particles and negatively chargeable lubricant particles in combination.

  The positively chargeable lubricant particles are lubricant particles that are positively charged by frictional charging between the carrier and the charging blade. Such lubricant particles are known, and metal salt particles of fatty acids are preferably exemplified. Examples of such fatty acid metal salts include zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc laurate, zinc myristate, zinc palmitate, zinc oleate, etc., among which stearic acid More preferred are zinc and magnesium stearate. The content of the positively chargeable lubricant particles is preferably 0.01 to 0.5 parts by mass and preferably 0.03 to 0.2 parts by mass with respect to 100 parts by mass of the toner base particles. More preferred. The positively chargeable lubricant particles may be of a single type or a combination of two or more types.

  The negatively chargeable lubricant particles are lubricant particles that are negatively charged by frictional charging between the carrier and the charging blade. Such lubricant particles are known, and polytetrafluoroethylene (PTFE), silicone, boron nitride, polymethyl methacrylate (PMMA), and polyvinylidene fluoride are preferably exemplified. Among them, boron nitride, polytetrafluoroethylene are preferred. (PTFE) is more preferably exemplified. The content of the negatively chargeable lubricant particles is preferably 0.01 to 0.5 parts by mass and preferably 0.03 to 0.2 parts by mass with respect to 100 parts by mass of the toner base particles. More preferred. The negatively chargeable lubricant particles may be of a single type or a combination of two or more types. It is preferable that the absolute value of the charge amount per unit mass (for example, 1 g) of the negatively chargeable lubricant particles is larger than the absolute value of the charge amount per unit mass (for example, 1 g) of the toner base particles.

  In the toner of the present invention, in addition to the above components, other components may be used as external additives. These components have the role of adhering to the surface of the toner base particles to improve the charging characteristics of the toner base particles or being separated from the toner base particles to improve the fluidity of the toner. . As such a component, inorganic oxide particles are preferably used.

  Examples of the inorganic oxide particles include silica, alumina, titania, zirconia, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, and boron oxide. Among these, silica can be mentioned preferably. The inorganic oxide particles can be used alone or in combination of two or more.

  The surface of the inorganic oxide particles is preferably subjected to a hydrophobic treatment. As a method of hydrophobizing treatment, a conventionally known hydrophobizing agent is brought into contact with the surface of the inorganic oxide particle before hydrophobizing treatment, and a hydrophobic functional group or component is chemically bonded to the surface of the inorganic oxide particle. The method of making it attach or attach is mentioned. The hydrophobizing agent for hydrophobizing the inorganic oxide particles is not particularly limited, and conventionally known ones can be exemplified. Preferred examples of such a hydrophobizing agent include octyltriethoxysilane, polydimethylsiloxane, dimethyldichlorosilane, hexamethyldisilazane, and the like. These hydrophobizing agents can be used alone or in combination of two or more. Commercially available hydrophobized inorganic oxide particles may be used as the inorganic oxide particles.

  The amount of the inorganic oxide particles added as an external additive can be about 2 to 12 parts by mass with respect to 100 parts by mass of the toner base particles, and is appropriately adjusted to obtain desired performance. be able to.

<Preparation of toner>
The toner is prepared by mixing the toner base particles and the external additive. At that time, other components may be appropriately added in order to improve various characteristics of the toner.

  Examples of the mixing device used when mixing the toner base particles and the external additive include a Henschel mixer and a super mixer. The mixing apparatus is not limited to these, and any mixing apparatus can be used as long as the apparatus can mix powder.

  Hereinafter, the toner for developing an electrostatic charge image of the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, “%” means “mass%” and “part” means “part by mass”.

[Preparation of toner base particles]
64.5 parts of a commercially available polyester resin (trade name: FC1565, manufactured by Mitsubishi Rayon Co., Ltd.) as a binder resin, and 15.6 of a polyester resin commercially available as a binder resin (trade name: ER561, manufactured by Mitsubishi Rayon Co., Ltd.) Parts, 11.9 parts of a yellow colorant (Pigment Yellow 180 colorant) as a colorant, 4 parts of a charge control agent, and a fatty acid ester wax (trade name: WE-10, manufactured by NOF Corporation) as a release agent 4 parts were mixed with a Henschel mixer and then melt-kneaded using a twin screw extruder. The obtained kneaded material is melted and solidified, coarsely pulverized with a funnel plex, then finely pulverized with a jet mill, classified using an air classifier, and a negatively chargeable toner having a volume median particle size of 7.5 μm Mother particles were obtained.

[Toner Preparation]
Each material was blended according to the blending described in Tables 1 and 2 and then mixed for 5 minutes with a Henschel mixer to obtain toners of Examples 1 to 4 and Comparative Examples 1 to 3. In addition, the compounding quantity shown to Table 1 and 2 is a mass part. In Tables 1 and 2, “silica particles” are negative polarity silica particles (BET surface area; 50 m ² / g) surface-treated with hexamethyldisilazane, zinc stearate particles, boron nitride particles, PTFE particles, and Silicone particles are lubricant particles, among which zinc stearate particles are positively charged, and boron nitride particles, PTFE particles, and silicone particles are negatively charged. Further, in Tables 1 and 2, “titanium oxide particles” are titanium oxides surface-treated with alkylsilane having an average primary particle diameter of 15 nm.

[Printing test under high image rate conditions (filming)]
Using a non-magnetic two-component negative charge electrification compound machine for evaluation, 13,000 sheets of a 90% printing rate chart were printed in an environment with a temperature of 25 ° C and a humidity of 50%, and the occurrence of filming was confirmed. did. The evaluation when the filming occurrence was recognized as “×”, the filming occurrence was not recognized as “◯”, and the case where the filming was recognized as being in the middle of both was evaluated as “△”. The results are shown in the “Filming” column of Tables 1 and 2.

[Printing test under low image area ratio]
Using a non-magnetic two-component negative charge electrification compound machine for evaluation, 13,000 sheets of a 5% printing rate chart were printed in an environment of a temperature of 25 ° C. and a humidity of 50%, and the status of PCR contamination was confirmed . When the occurrence of PCR contamination is recognized as “x”, the practically problematic PCR contamination is not identified as “◯”, and the presence of the middle of both is denoted as “△” The evaluation results are shown in the “PCR stain” column of Tables 1 and 2.

  As shown in Tables 1 and 2, according to the toner of the present invention, the filming in the high image rate image and the PCR stain in the low image rate image are suppressed, and the photoconductor surface is excellent in cleanability. Is understood.

Claims (5)

Including toner base particles and external additives,
An electrostatic charge image developing toner comprising both positively charged lubricant particles and negatively charged lubricant particles as components of the external additive.   The positively chargeable lubricant particles are at least one selected from the group consisting of fatty acid metal salts, and the negatively chargeable lubricant particles are boron nitride, polytetrafluoroethylene, polyvinylidene fluoride, polymethacryl 2. The electrostatic image developing toner according to claim 1, wherein the toner is at least one selected from the group consisting of methyl acid and silicone.   The content of the positively chargeable lubricant particles is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the toner base particles, and the content of the negatively chargeable lubricant particles is the toner. The toner for developing an electrostatic charge image according to claim 1, wherein the amount is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the base particles.   The electrostatic image developing toner according to claim 1, wherein the negatively chargeable lubricant particles contain boron nitride.   The electrostatic image developing toner according to claim 1, wherein the positively chargeable lubricant particles include zinc stearate.