JP2017227814A - toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner that can uniformly suppress image deletion.SOLUTION: There is provided a toner including toner particles each containing a binder resin, colorant, and wax, and inorganic fine particles. The toner has an average circularity of 0.950 or more; the inorganic fine powder particle includes a magnesium carbonate particle, and an inorganic fine particle A having a new Mohs hardness of 6 or more and 13 or less; the magnesium carbonate particle includes primary particles having a number average diameter of 30 nm or more and 300 nm or less; and the toner has a toner surface coverage of 5.0 area% or more with the inorganic fine particles A having a particle diameter of 70 nm or more and 300 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to a toner used in an electrophotographic system, an electrostatic recording system, and an electrostatic printing system.

Conventionally, an image forming method and an image forming apparatus using an electrophotographic system have been widely used. In the electrophotographic system, an electrophotographic photosensitive member (photosensitive member) using a photoconductive material as an image carrier is uniformly charged to a required polarity and potential, and then exposed according to an image pattern. Then, an electric latent image (electrostatic latent image) is formed on the photosensitive member. Thereafter, the electrostatic latent image on the photosensitive member is developed with toner to be visualized, transferred to a transfer material (transfer medium) such as paper, and fixed.
One of the problems in the electrophotographic image forming method and the image forming apparatus is the duty cycle of the apparatus main body. The duty cycle is a limit number of sheets in which the apparatus main body continues to operate normally without requiring maintenance by an operator.
One of the biggest factors that control the duty cycle is the life of the photoreceptor. If the life of the photoreceptor can be extended, it is possible to reduce waste, that is, reduce consumables, extend the life of consumables, and improve reliability.
Under such a background, highly durable photoconductors such as amorphous silicon (a-Si) photoconductors and organic photoconductors having a protective layer of a curable resin on the surface have been widely used as photoconductors. .
However, according to studies by the present inventors, the higher the durability of the photoconductor, the more easily the deterioration of the surface state of the photoconductor is accumulated, and as a result, the possibility of affecting the image quality increases.
Examples of the surface change of the photoreceptor that affects the image quality include the following. That is, fine paper dust generated from a piece of paper used as a transfer material in many cases, organic components deposited therefrom, and discharge products generated due to the presence of a high voltage application member in the apparatus are It is by adhering to the surface. In particular, the discharge product adhering to the surface of the photoconductor dissolves in moisture on the surface of the photoconductor in a high humidity environment, and the surface of the photoconductor becomes low in electrical resistance, thereby preventing the formation of a clear electrostatic latent image. Degradation of image quality called image blur).
As a countermeasure against the problem when such a highly durable photoconductor is used, there is a method of scraping the surface of the deteriorated photoconductor. That is, it is a method in which a new surface always appears on the surface of the photosensitive member by a scraping member or an abrasive. However, by simply polishing the photoconductor, it is difficult to sufficiently suppress the image flow due to the low electrical resistance of the surface due to the adhesion of discharge products while appropriately suppressing the amount of polishing and the generation of scratches. is there.
In response to the problem of image quality degradation due to the discharge product adhering to the surface of the photoconductor, an alkaline earth metal carbonate particle is externally added to the toner, and the toner is adsorbed or reacted to remove it from the surface of the photoconductor. There is a technique for effectively preventing image flow.
Patent Document 1 discloses a technique for preventing image flow using calcium carbonate or magnesium carbonate particles and a layered double hydroxide.
Patent Document 2 discloses a technique for preventing image blur by using particles having carbonate on the surface of alkaline earth metal titanate particles.
Patent Document 3 discloses a technique for preventing image flow by using a combination of low-hardness particles and high-hardness particles having a constant particle size, and among them, alkaline earth metal carbonate particles are used. Yes.

JP 2012-93554 A JP 2013-25223 A JP 2012-83497 A

As described in Patent Documents 1 to 3 above, an image flow prevention technique in the case of using alkaline earth metal carbonate particles is effective. During the technical study, a toner to which magnesium carbonate particles are added is used. As a result, it was confirmed that the recovery rate is very high when a large amount of discharge products accumulate on the surface of the photoreceptor and the degree of image flow becomes severe.
On the other hand, it has been found that there are cases where it is possible to suppress image flow and where it is difficult to suppress when using toner with externally added magnesium carbonate particles. Specifically, when there is a bias in the image in the longitudinal and horizontal direction of the photoconductor, it is difficult to exert the effect of suppressing image flow. More specifically, when image output of a vertical ruled line image is repeated, there is a difference in the degree of image flow between the place where the toner is developed on the photoconductor and the place where the toner is not developed, and the boundary is conspicuous There has occurred.
The effect of suppressing the image flow is largely due to the fact that the toner containing carbonate particles comes into contact with the surface of the photoreceptor and rubs. The electrophotographic process in which the toner is rubbed most with the surface of the photoreceptor is the photoreceptor cleaning process, and the toner is mainly transferred to the transfer residual toner to the photoreceptor cleaning process, but the transfer residual toner is developed on the photoreceptor. Depending on the pattern of the image to be carried, the transported location may be biased in the longitudinal direction of the photoreceptor. Usually, a certain degree of bias is diffused to some extent in the longitudinal direction of the photoreceptor due to the phenomenon of horizontal running due to toner flow. The toner to which magnesium carbonate particles are externally added has poor horizontal running performance in the cleaning process, and the photoreceptor longitudinal uniformity that absorbs discharge products on the photoreceptor surface is inferior, resulting in a difference between a good image portion and a bad portion. It is easy to come out.
An object of the present invention is to provide a toner capable of uniformly suppressing deterioration of the surface of the photoconductor and suppressing high-cost image formation while suppressing the wear and scratches of the photoconductor.

The above object is achieved by the electrophotographic image forming toner according to the present invention. In summary, the present invention has an average circularity of 0.950 or higher,
The inorganic fine particles include magnesium carbonate particles and inorganic fine particles A having a new Mohs hardness of 6 to 13,
The magnesium carbonate particles have a number average diameter of primary particles of 30 nm to 300 nm,
The toner is characterized in that the toner surface coverage by the inorganic fine particles A having a particle diameter of 70 nm or more and 300 nm or less is 5.0 area% or more.

  According to the present invention, even when an image formation pattern such as a vertical ruled line image is biased in the longitudinal direction of the photoconductor in a high humidity environment, uniform image output with less non-uniform image quality due to image flow is performed. Toner that can be provided can be provided.

  The toner of the present invention contains magnesium carbonate particles having a particle size of 30 nm or more and 300 nm or less, and particles having a certain size or more on the toner surface and a new Mohs hardness (corrected Mohs hardness) of 6 or more and 13 or less are 5.0 areas. It is important that at least% is coated. When a toner satisfying this condition is prepared, and a half-tone image is output after an image of a vertical ruled line pattern is output with an electrophotographic printer in a high-humidity environment, an image with a uniform density can be formed. It was. The mechanism is considered as follows.

  The surface of the magnesium carbonate particles reacts with the discharge product to absorb the discharge product together with moisture. Magnesium carbonate after reacting and absorbing the discharge product has increased adhesion and fluidity, and toner fluidity decreases. In contrast, the toner of the present invention is covered with particles that are large and have a certain level of hardness, reducing the chance of contact between the toners or the photoreceptor surface and magnesium carbonate, and destroying the contact area of magnesium carbonate. It is thought that fluidity can be maintained because it becomes easier.

  The toner of the present invention contains magnesium carbonate particles containing a binder resin, a colorant, and a wax (release agent), and having an average circularity of 0.950 or more and an average particle size of 30 nm to 300 nm. In addition, it is characterized in that particles having a new Mohs hardness of 6 or more and 13 or less and 70 nm or more and 300 nm or less are coated on the toner surface by 5.0 area% or more.

<Binder resin>
In order to disperse the colorant and the wax as the binder resin, it is preferable to use an amorphous resin.

  The amorphous resin is not particularly limited, but styrenes (for example, styrene, chlorostyrene, etc.), monoolefins (for example, ethylene, propylene, butylene, isoprene, etc.), vinyl esters (for example, vinyl acetate, vinyl propionate). , Vinyl benzoate, vinyl butyrate, etc.), α-methylene aliphatic monocarboxylic acid esters (for example, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, Ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether), vinyl ketones (eg, vinyl methyl ketone, vinyl hexyl ketone, vinyl isopate) Homopolymers and copolymers of Peniruketon etc.), etc., and polyester resins by copolymerization of dicarboxylic acids and diols.

  In particular, typical amorphous resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride. A copolymer, a polyethylene resin, a polypropylene resin, a polyester resin, etc. are mentioned.

  Typical amorphous resins also include polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  The content of the amorphous resin is, for example, preferably 40% to 95% by mass, desirably 50% to 90% by mass, and more desirably 60% to 85% by mass. is there.

  It is preferable to mix a resin having a low molecular weight and a resin having a high molecular weight in order to prevent low temperature fixability and high temperature hot offset.

  Further, for the purpose of further improving the dispersibility of the pigment and wax, and improving the charging stability and blocking resistance of the toner, a different resin can be contained in the main resin.

<Crystalline resin>
The toner of the present invention preferably contains a crystalline resin in addition to the amorphous resin as the binder resin, and preferably contains a crystalline polyester or a crystalline polyether. The crystalline resin in the present invention is a resin in which an endothermic peak is observed in differential scanning calorimetry (DSC). By including a crystalline resin in the toner of the present invention, the electric resistance of the toner can be reduced and the electrostatic charge of the untransferred toner can be reduced. This is preferable because it can improve the fluidity of the transfer residual toner. As in the present invention, the toner containing magnesium carbonate particles causes a decrease in fluidity of the transfer residual toner in a high humidity environment, and as a result, the external additive released from the toner having the function of maintaining the lubricity of the photoreceptor cleaning. The fluidity also decreases, and the frictional force between the cleaning blade and the photosensitive member tends to increase. Due to the electrostatic relaxation effect of the toner, electrostatic aggregation of the external additive and separation from the toner are likely to occur, the friction between the cleaning blade and the photoreceptor is stabilized, and toner slipping is less likely to occur.

  The crystalline polyester is obtained by polycondensation reaction of a monomer composition containing an aliphatic diol having 2 to 22 carbon atoms and an aliphatic dicarboxylic acid having 2 to 22 carbon atoms as main components.

  The aliphatic diol having 2 to 22 carbon atoms (more preferably 8 to 12 carbon atoms) is not particularly limited, but is preferably a chain (more preferably linear) aliphatic diol, for example, , Ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,4-butadiene glycol, trimethylene glycol, tetramethylene glycol, Examples include pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, and neopentyl glycol. Of these, linear aliphatic groups such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and α, ω-diol are particularly preferred.

  Among the alcohol components, preferably 50% by mass or more, more preferably 70% by mass or more is an alcohol selected from aliphatic diols having 2 to 22 carbon atoms.

  In the present invention, a polyhydric alcohol monomer other than the aliphatic diol can also be used. Among the polyhydric alcohol monomers, examples of the dihydric alcohol monomer include aromatic alcohols such as polyoxyethylenated bisphenol A and polyoxypropylenated bisphenol A; 1,4-cyclohexanedimethanol and the like. Among the polyhydric alcohol monomers, trihydric or higher polyhydric alcohol monomers include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; pentaerythritol, dipentaerythritol, tripentaerythritol. 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and the like Group alcohol and the like.

  Furthermore, in this invention, you may use a monovalent alcohol to such an extent that the characteristic of crystalline polyester is not impaired. Examples of the monovalent alcohol include monofunctional groups such as n-butanol, isobutanol, sec-butanol, n-hexanol, n-octanol, lauryl alcohol, 2-ethylhexanol, decanol, cyclohexanol, benzyl alcohol, and dodecyl alcohol. And alcohol.

  On the other hand, the aliphatic dicarboxylic acid having 2 to 22 carbon atoms (more preferably 6 to 14 carbon atoms) is not particularly limited, but is a chain (more preferably linear) aliphatic dicarboxylic acid. Is preferred. Specific examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, Examples include maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid, and those obtained by hydrolyzing these acid anhydrides or lower alkyl esters.

  In the present invention, among the carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more is a carboxylic acid selected from aliphatic dicarboxylic acids having 2 to 22 carbon atoms.

  In the present invention, a polyvalent carboxylic acid other than the aliphatic dicarboxylic acid having 2 to 22 carbon atoms may be used. Among the other polyvalent carboxylic acid monomers, divalent carboxylic acids include aromatic carboxylic acids such as isophthalic acid and terephthalic acid; n-dodecyl succinic acid, n-dodecenyl succinic aliphatic carboxylic acid; cyclohexane dicarboxylic acid Examples thereof include alicyclic carboxylic acids such as acids, and these acid anhydrides or lower alkyl esters are also included. Among the other carboxylic acid monomers, trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, Aromatic carboxylic acids such as 2,4-naphthalenetricarboxylic acid and pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2 -Aliphatic carboxylic acids such as methylene carboxypropane and derivatives of these acid anhydrides or lower alkyl esters are also included.

  Furthermore, in this invention, you may contain monovalent carboxylic acid to such an extent that the characteristic of crystalline polyester is not impaired. Examples of the monovalent carboxylic acid include benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, octanoic acid, decanoic acid, Examples thereof include monocarboxylic acids such as dodecanoic acid and stearic acid.

  The crystalline polyester in the present invention can be produced according to an ordinary polyester synthesis method. For example, the above-mentioned carboxylic acid monomer and alcohol monomer are esterified or transesterified, and then subjected to a polycondensation reaction in accordance with a conventional method under reduced pressure or by introducing nitrogen gas. Crystalline polyester can be obtained.

  The esterification or transesterification reaction can be performed using a normal esterification catalyst or transesterification catalyst such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, and magnesium acetate, if necessary.

  The polycondensation reaction can be carried out using a conventional polymerization catalyst, for example, a known catalyst such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide. . The polymerization temperature and the catalyst amount are not particularly limited, and may be determined appropriately.

  In the esterification or transesterification reaction or polycondensation reaction, all monomers are charged together to increase the strength of the resulting crystalline polyester, or divalent monomers are first reacted to reduce low molecular weight components. Then, a method of adding a trivalent or higher monomer and reacting the monomer may be used.

  Examples of the crystalline polyether include a polyhydric alcohol homopolymer and a copolymer of two or more polyhydric alcohols. More specifically, as the crystalline polyether, 1) a polymer of an aliphatic polyhydric alcohol, 2) a polymer of an aliphatic polyhydric alcohol and an aromatic polyhydric alcohol, 3) An aromatic polyhydric alcohol polymer may be mentioned.

  Here, as the crystalline polyether, from the viewpoint of imparting crystallinity, 1) a polymer of an aliphatic polyhydric alcohol and 2) an aliphatic polyhydric alcohol and an aromatic polyhydric alcohol. A polymer is good, and 1) is particularly desirable.

  Examples of the aliphatic polyhydric alcohol include alkylene diol, glycerin, trimethylolpropane, pentaerythritol having an alkylene group having 6 to 20 carbon atoms (preferably 6 to 12 and more preferably 8 to 12). Etc.

  Examples of the aromatic polyhydric alcohol include bisphenols such as bisphenol A and bisphenol F, hydroquinone, resorcin, catechol, pyrogallol, or their ethylene oxide, propylene oxide adduct, xylylene glycol, and the like.

The crystalline polyether is particularly preferably a crystalline polyether having only a repeating unit represented by the following general formula (1).
[— (CH ₂ ) n—O—] General formula (1)

  In said general formula (1), n shows the integer of the range of 6-20. In particular, n in the general formula (1) preferably represents an integer in the range of 6 to 12, more preferably n represents an integer in the range of 8 to 12.

  The weight average molecular weight (Mw) of the crystalline polyether is, for example, 2000 or more and 200000 or less, desirably 3000 or more and 100000 or less, and more desirably 3000 or more and 30000 or less.

  The melting temperature of the crystalline polyether is, for example, 40 ° C. or more and 120 ° C. or less, and desirably 50 ° C. or more and 100 ° C. or less.

  The content of the crystalline polyether is preferably 1% by mass or more and 50% by mass or less, and more preferably 2% by mass or more and 20% by mass or less with respect to the toner.

<Wax (release agent)>
Examples of the wax used in the toner of the present invention include the following. Low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymer, hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxide of hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof; Waxes mainly composed of fatty acid esters such as carnauba wax; those obtained by partially or fully deoxidizing fatty acid esters such as deoxidized carnauba wax. Furthermore, the following are mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Saturated alcohols such as sil alcohols; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, montanic acid, and stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, Esters with alcohols such as sil alcohols; Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; Methylene bis stearic acid amide, ethylene biscapric acid Saturated fatty acid bisamides such as amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N 'dioleyl adipic acid amide, N, N' dioleyl Of unsaturated fatty acid amides such as sebacic acid amide; aromatic bisamides such as m-xylene bis stearic acid amide, N, N ′ distearyl isophthalic acid amide; calcium stearate, calcium laurate, zinc stearate, magnesium stearate Aliphatic metal salts such as those commonly referred to as metal soaps; waxes grafted to aliphatic hydrocarbon waxes using vinylic monomers such as styrene and acrylic acid; fatty acids such as behenic acid monoglycerides Alcohol Partial ester; methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable fats and oils.

  Among these waxes, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax or fatty acid ester waxes such as carnauba wax are preferable from the viewpoint of improving low-temperature fixability and hot offset resistance. In the present invention, a hydrocarbon-based wax is more preferable in that the crystalline polyester and the wax are separately dispersed and the dispersibility is further improved.

  In the present invention, the wax is preferably used in an amount of 1 to 20 parts by mass per 100 parts by mass of the binder resin.

  Moreover, in the endothermic curve at the time of temperature rise measured with a differential scanning calorimetry (DSC) apparatus, the peak temperature of the maximum endothermic peak of the wax is preferably 45 ° C. or higher and 140 ° C. or lower. It is preferable that the peak temperature of the maximum endothermic peak of the wax is within the above range because both the storage stability of the toner and the hot offset resistance can be achieved.

<Colorant>
Examples of the colorant that can be contained in the toner include the following.

  Examples of the black colorant include carbon black; those prepared by using a yellow colorant, a magenta colorant, and a cyan colorant and adjusting the color to black. As the colorant, a pigment may be used alone, but it is more preferable from the viewpoint of the image quality of a full-color image to improve the sharpness by using a dye and a pigment together.

  Examples of the magenta toner pigment include the following. C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35.

  Examples of the magenta toner dye include the following. C. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; I. Disper thread 9; I. Solvent violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. B. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; I. Basic dyes such as Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

  Examples of the cyan toner pigment include the following. C. I. Pigment blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.

  Examples of cyan toner dyes include C.I. I. There is Solvent Blue 70.

  Examples of the yellow toner pigment include the following. C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; I. Bat yellow 1, 3, 20

  Examples of the dye for yellow toner include C.I. I. There is Solvent Yellow 162.

  The amount of the colorant used is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the binder resin.

<Charge control agent>
The toner may contain a charge control agent as necessary. As the charge control agent contained in the toner, known ones can be used. In particular, a metal compound of an aromatic carboxylic acid that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable.

  Negative charge control agents include salicylic acid metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymeric compounds having sulfonic acid or carboxylic acid in the side chain, sulfonates or sulfonated compounds in the side chain. Examples thereof include a polymer compound, a polymer compound having a carboxylate or a carboxylic acid ester in the side chain, a boron compound, a urea compound, a silicon compound, and calixarene. Examples of the positive charge control agent include quaternary ammonium salts, polymer compounds having the quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds. The charge control agent may be added internally or externally to the toner particles. The addition amount of the charge control agent is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

<Magnesium carbonate particles>
The toner of the present invention contains magnesium carbonate particles.

  Magnesium carbonate is not particularly limited, and commercially available products can also be used. Moreover, what is obtained by any manufacturing method can be used.

  The method of adding magnesium carbonate to the toner is preferably externally added to the toner particle surface. The content in the toner is preferably 0.02% by mass or more and 1.00% by mass or less. Magnesium carbonate particles are more reactive to discharge products than other carbonate particles, and therefore are preferably added in a small amount to the toner, more preferably 0.4% by mass or less.

  In the present invention, the magnesium carbonate particles have a number average particle size of primary particles of 30 nm or more and 300 nm or more in order to exhibit the image flow inhibiting performance. If the number average particle diameter is less than 30 nm, it tends to adhere to the photoreceptor and is difficult to remove. When the number average particle size is larger than 300 nm, the absorbability of the discharge product is lowered, and the image flow suppression performance is not sufficiently exhibited.

  In addition, about the particle size of the inorganic fine particle in this invention, 100 particle size was measured at random from the photograph image | photographed with the magnification of 50,000 times with the electron microscope, and the average value was calculated | required. The particle diameter was determined by (a + b) / 2, where a is the longest side of the primary particles and b is the shortest side.

  Magnesium carbonate has inherent properties of absorbing moisture in the air and reacting with acids. It is desirable to hydrophobize the surface of the magnesium carbonate particles with hydrophobic molecules in order to reduce the change in physical properties and provide charging stability in a place other than where the effects of the present invention are exhibited.

  The surface treatment for hydrophobizing includes a method of adsorbing fatty acids and derivatives, resin acids and derivatives thereof, other organic carboxylic acids and salts thereof, or titanate and silane coupling agents alone or in combination. is there. Of these, fatty acids and derivatives, and resin acids and derivatives thereof are preferred. Although it does not specifically limit as a fatty acid or its derivative (s), For example, a fatty acid, its metal salt, its esterified substance, etc. can be used conveniently. Examples of fatty acids include caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, palmitoleic acid, oleic acid, erucic acid, and the like. Examples of the metal salt include alkali metal salts such as sodium salts and potassium salts of the above fatty acids, and alkaline earth metal salts such as magnesium salts and calcium salts. Examples of the esterified product include stearyl stearate, lauryl stearate, stearyl palmitate, and lauryl palmitate. These can be used alone or in combination of two or more. Among these, fatty acids having 6 to 31 carbon atoms and derivatives thereof can be suitably used.

  Although it does not specifically limit as resin acid and its derivative (s), For example, resin acid, its metal salt, its esterified substance, etc. can be used conveniently. Examples of the resin acid include abietic acid, lepopimaric acid, neoabietic acid, pultrinic acid, dehydroapitic acid, dihydroabietic acid, tetraabietic acid, dextropimaric acid, and isodextropimaric acid. Examples of the metal salt include alkali metal salts such as sodium salt and potassium salt of the resin acid, alkaline earth metal salts such as magnesium salt and calcium salt, and the like. In addition to these, hydrogenated rosin, disproportionated rosin, polymerized rosin, rosin ester, maleated rosin, maleated rosin ester, rosin-modified phenol, and the like can be given as resin acid derivatives.

  Although it can determine suitably according to kinds, such as a fatty acid, Usually, at least 1 sort (s) of a fatty acid, its derivative (s), resin acid, and its derivative (s) is 0.1 mass part or more and 30 mass parts with respect to 100 mass parts of magnesium carbonate. It may be about the following, preferably 0.2 to 20 parts by mass, more preferably 0.2 to 5 parts by mass.

  Surface treatment of hydrophobic molecules on magnesium carbonate includes spraying directly onto magnesium carbonate dry powder, adding to magnesium carbonate slurry, adding to magnesium carbonate dehydrated cake, wet pulverizing magnesium carbonate There is. Preferably, it is added to a magnesium carbonate-containing aqueous material (a concentrated solution obtained by concentrating the magnesium carbonate reaction slurry, a dehydrated cake obtained by dehydrating the light magnesium carbonate reaction slurry, and an aqueous slurry dissolving the light magnesium carbonate dry powder), and a mixing treatment is performed. The mixing treatment is preferably a liquid stirring type, and is performed using a mixing tank and a mixing pump. A baffle plate can be installed in the liquid stirring type device to increase the shearing force of the liquid. A stirrer with a strong shearing force can be processed in a short time, and if it is weak, the process may be performed for a long time. Any mixing tank of liquid stirring type can be used.

<Inorganic fine particles having a new Mohs hardness of 6 to 13>
In addition to magnesium carbonate, the toner of the present invention contains inorganic fine particles having a new Mohs hardness of 6 or more and 13 or less, and the toner surface is coated with particles of 70 nm or more and 300 nm or less of 5.0% by area or more. In order to provide the fluidity of the transfer residual toner of the toner of the present invention, it is necessary that many particles of 70 nm or more exist on the toner surface.

  When the particle diameter is 70 nm or more, when the toner is mechanically loaded and embedded in the toner surface in the transfer process or cleaning process, it reacts with the discharge product on the toner surface to increase adhesion. The influence of the deteriorated magnesium carbonate particles on the toner fluidity can be reduced. When the particle diameter is larger than 300 nm, the toner particles are easily detached or moved from the toner surface, and the deteriorated magnesium carbonate affects the fluidity of the transfer residual toner.

  Further, when the new Mohs hardness is 6 or more, an impact can be given to the adhering portion between the deteriorated magnesium carbonate and the surface of the photoconductor, so that the fluidity of the transfer residual toner on the surface of the photoconductor can be maintained. When the new Mohs hardness is greater than 13, dents and scratches are generated at locations where the toner contacts, such as the photoreceptor and the cleaning member, and toner components adhere to and accumulate from the dents and scratches, and the image flow is worsened.

  Furthermore, as the particles, metal oxides such as silicon oxide, titanium oxide, aluminum oxide, cerium oxide, magnesium oxide, zirconium oxide and the like that are difficult to react with discharge products, and composite metal oxides thereof are preferable, silicon oxide, Titanium oxide, aluminum oxide, cerium oxide, and zirconium oxide are more preferable. Two or more of these particles can be used in combination. In that case, it is preferable to use particles having a difference in Mohs hardness.

  The amount added to the toner is preferably 0.5 times or more and 8.0 times or less, and more preferably 1.5 times or more and 6.0 times or less with respect to the mass content of the magnesium carbonate particles in the toner. The phenomenon that the deteriorated magnesium carbonate adheres to the cleaning blade due to the particles satisfying this condition and hinders the horizontal running performance of the untransferred toner in cleaning can be suppressed, and the image flow uniformity suppressing performance can be maintained for a long time. This effect is more preferably an inorganic fine particle having a new Mohs hardness of 11 or more and 12 or less.

<Other inorganic fine particles>
The toner of the present invention may contain inorganic fine particles other than those described above as necessary. The inorganic fine particles may be added internally to the toner particles as an internal additive, or may be mixed with the toner particles as an external additive.

  As the external additive, metal oxide particles such as silica, titania, and alumina are preferable from the viewpoint of fluidity and charging stability in the development process and the transfer process. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof. The external additive used from the viewpoint of fluidity and charging stability is preferably used in an amount of 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the toner particles. For mixing the toner particles and the external additive, a known mixer such as a Henschel mixer can be used.

<Developer>
The toner of the present invention can also be used as a one-component developer, but in order to further improve dot reproducibility, it can be mixed with a magnetic carrier and used as a two-component developer. Is preferable in that it is obtained.

  Examples of the magnetic carrier include iron powder whose surface is oxidized, non-oxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, and the like Magnetic material dispersed resin carriers (so-called resin carriers) containing magnetic materials such as alloy particles, oxide particles, ferrite, and the like, and magnetic materials and binder resins that hold the magnetic materials in a dispersed state are generally known. Things can be used.

  When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio at that time is 2% by mass or more and 15% by mass or less, preferably as a toner concentration in the two-component developer. In general, good results are obtained when the content is from 4% by mass to 13% by mass.

<Manufacturing method>
As a method for producing toner particles, since it is necessary to melt and knead the binder resin, the colorant, and the wax, the binder resin, the colorant, and the wax are melt-kneaded, and the kneaded product is cooled, A pulverization method of pulverization and classification is preferred.

  Hereinafter, a toner manufacturing procedure using the pulverization method will be described.

  In the raw material mixing step, as a material constituting the toner particles, for example, a binder resin and a wax, and other components such as a colorant and a charge control agent as required are weighed and mixed in a predetermined amount and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano-hybrid (manufactured by Nippon Coke Industries, Ltd.)

  Next, the mixed material is melt-kneaded to disperse wax, crystalline polyester, and the like in the binder resin. In the melt-kneading process, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. From the advantage that continuous production is possible, a single-screw or twin-screw extruder has become the mainstream. Yes. For example, KTK type twin screw extruder (manufactured by Kobe Steel Co., Ltd.), TEM type twin screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikekai Tekko), twin screw extruder (manufactured by K.C.K. ), Co-kneader (manufactured by Buss), kneedex (manufactured by Nippon Coke Industries Co., Ltd.), and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

  Next, the cooled product of the resin composition is pulverized to a desired particle size in the pulverization step. In the pulverization step, for example, after coarse pulverization with a pulverizer such as a crusher, a hammer mill, or a feather mill, for example, a kryptron system (manufactured by Kawasaki Heavy Industries), a super rotor (manufactured by Nisshin Engineering), a turbo mill Finely pulverize with a turbomill (made by Turbo Industries) or air jet type fine pulverizer.

  Then, if necessary, classification such as inertial class elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.), centrifugal classification turboplex (manufactured by Hosokawa Micron), TSP separator (manufactured by Hosokawa Micron), Faculty (manufactured by Hosokawa Micron) The toner particles are obtained by classification using a machine or a sieving machine.

  Thereafter, external additives such as inorganic fine powder and resin particles selected as necessary may be added and mixed (externally added). For example, an external additive can be added to impart fluidity, and toner particles before heat treatment can be obtained.

  As the mixing device, a mixing device having a rotating body having a stirring member and a main casing provided with a gap between the stirring member and the stirring member is used. As an example of such a mixing apparatus, Henschel mixer (made by Mitsui Mining Co., Ltd.); Super mixer (made by Kawata Corp.); Ribocorn (made by Okawara Seisakusho Co., Ltd.); Nauter mixer, turbulizer, cyclomix (made by Hosokawa Micron Corp.) A spiral pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.); a radige mixer (manufactured by Matsubo), and nobilta (manufactured by Hosokawa Micron Corporation). In particular, a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) is preferably used to uniformly mix and loosen the silica aggregates.

  The mixing apparatus conditions include the processing amount, the stirring shaft rotation speed, the stirring time, the stirring blade shape, the temperature in the tank, etc. In order to achieve the desired toner performance, various physical properties of the toner particles and additives It is appropriately selected in view of the type and the like, and is not particularly limited.

  Furthermore, by applying heat or a mechanical load to the toner particles obtained by the above-described production method, it is possible to enhance the hydrophobicity of the toner particle surfaces and to modify the surface shape and the like.

  Thereafter, external additives such as inorganic fine powder and resin particles selected as necessary are added and mixed (externally added), for example, to improve fluidity and charge stability, thereby obtaining a toner. As the mixing device, a mixing device having a rotating body having a stirring member and a main casing provided with a gap between the stirring member and the stirring member is used.

  As an example of such a mixing apparatus, Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); A spiral pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.); a radige mixer (manufactured by Matsubo), and nobilta (manufactured by Hosokawa Micron Corporation). In particular, a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) is preferably used to uniformly mix and loosen the silica aggregates.

  The mixing apparatus conditions include the amount of processing, the number of stirring shaft rotations, the stirring time, the shape of the stirring blade, the temperature in the tank, etc. In order to achieve the desired toner performance, various physical properties and additives of the heat-treated toner particles This is selected as appropriate in view of the type of the material, and is not particularly limited.

  Furthermore, for example, when a coarse aggregate of the additive is present in the obtained toner free, a sieving machine or the like may be used as necessary.

  A method for measuring various physical properties of toner and raw materials will be described below.

<Measurement method of toner surface coverage>
The toner coverage X of particles having a new Mohs hardness of 6 or more and 13 or less and 70 nm or more and 300 nm or less in the present invention was photographed with a Hitachi ultra-high resolution field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation). The toner surface image obtained by the image analysis software Image-Pro Plus ver. Calculated by 5.0 (Japan Roper Co., Ltd.). The image capturing conditions of S-4800 are as follows.

(1) Sample preparation A conductive paste is thinly applied to a sample table (aluminum sample table 15 mm × 6 mm), and toner is sprayed thereon. Further, air is blown to remove excess toner from the sample stage and sufficiently dry. The sample stage is set on the sample holder, and the height of the sample stage is adjusted to 36 mm by the sample height gauge.

(2) S-4800 observation condition setting The coverage X is calculated using an image obtained by the reflected electron image observation of S-4800. Since the reflected electron image has less charge-up of the inorganic fine particles than the secondary electron image, the coverage X can be measured with high accuracy. An elemental analysis is performed by an energy dispersive X-ray analyzer (EDAX), and an element of particles having a Mohs hardness of 6-13 and 70 nm or more and 300 nm or less is specified.

  Liquid nitrogen is poured into the anti-contamination trap attached to the S-4800 mirror until it overflows, and is placed for 30 minutes. The “PC-SEM” of S-4800 is activated and flushing (cleaning of the FE chip as an electron source) is performed. Click the acceleration voltage display part of the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute. Confirm that the emission current by flashing is 20 to 40 μA. Insert the sample holder into the sample chamber of the S-4800 mirror. Press [Origin] on the control panel to move the sample holder to the observation position.

  Click the acceleration voltage display section to open the HV setting dialog, and set the acceleration voltage to [0.8 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [Up (U)] and [+ BSE] for the SE detector, and select [+ BSE] in the selection box on the right. L. A. 100] to select a mode in which observation is performed with a reflected electron image. Similarly, in the [Basic] tab of the operation panel, the probe current of the electron optical system condition block is set to [Normal], the focus mode is set to [UHR], and the WD is set to [3.0 mm]. Press the [ON] button in the acceleration voltage display section of the control panel to apply the acceleration voltage.

(3) Focus adjustment The focus knob [COARSE] on the operation panel is rotated, and the aperture alignment is adjusted when the focus is achieved to some extent. Click [Align] on the control panel to display the alignment dialog and select [Beam]. The STIGMA / ALIGNMENT knob (X, Y) on the operation panel is rotated to move the displayed beam to the center of the concentric circle. Next, [Aperture] is selected, and the STIGMA / ALIGNMENT knobs (X, Y) are turned one by one to stop the movement of the image or adjust the movement to the minimum. Close the aperture dialog and focus with auto focus. Thereafter, the magnification is set to 50000 (50k), focus adjustment is performed using the focus knob and the STIGMA / ALIGNMENT knob in the same manner as described above, and the focus is again adjusted by autofocus. Repeat this operation again to focus. Here, since the measurement accuracy of the coverage rate tends to be low when the angle of inclination of the observation surface is large, select the one with the smallest possible surface inclination by selecting the one that focuses on the entire observation surface at the same time when adjusting the focus. And analyze.

(4) Image storage Brightness adjustment is performed in the ABC mode, and a photograph is taken with a size of 640 × 480 pixels and stored. The following analysis is performed using this image file. One photograph is taken for one toner particle, and an image is obtained for at least 30 toner particles.

(5) Image Analysis In the present invention, the coverage X is calculated by binarizing the image obtained by the above-described method using analysis software (Image-Pro Plus ver. 5.0). At this time, the one screen is divided into 12 squares and analyzed.

  The analysis conditions of the image analysis software are as follows.

  Select “Measure” from the tool bar, then select “Count / Size” and “Option” in this order, and set the binarization condition. Select 8 connections in the object extraction option and set smoothing to 0. In addition, sorting, filling holes, and inclusion lines are not selected, and “exclude boundary lines” is set to “none”. Select “Measurement Item” from “Measurement” on the tool bar, and input 2 to 107 as the area selection range.

  The coverage is calculated around a square area. At this time, the area (C) of the region is set to 24000 to 26000 pixels. “Treatment” —Automatic binarization by binarization, and the total area (D) of the area of the new Mohs hardness of 6 to 13 and no inorganic fine particles of 70 nm to 300 nm is calculated.

From the total area D of the area C of the square area and the area of the silica-free area, the coverage a is obtained by the following formula.
Coverage a (%) = 100− (D / C × 100)

  Let the average value of all the obtained data be the coverage X in this invention.

<Calculation of particle size>
The number average particle diameter of primary particles of silica fine particles is calculated from an image of the toner surface taken with a Hitachi ultra-high resolution field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation). The image capturing conditions of S-4800 are as follows.

  Similarly to the above-described “calculation of the coverage X”, the operations from (1) to (2) are performed, and the focus is adjusted by adjusting the focus of the toner surface at a magnification of 50,000 times, as in (3). Adjust the brightness in the mode. Then, after the magnification is set to 100,000, the focus is adjusted using the focus knob and the STIGMA / ALIGNMENT knob in the same manner as in (3), and the focus is further adjusted by autofocus. Repeat the focus adjustment again to focus at 100,000 times.

  Thereafter, the particle size of at least 300 inorganic fine particles on the toner surface is measured to determine the number average particle size of the primary particles. Here, since some silica fine particles exist as agglomerates, the number average particle diameter of the primary particles is obtained by calculating the maximum diameter of what can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter.

<Measurement of glass transition point of toner and melting point of wax>
The glass transition point of the toner in the present invention is measured using DSC Q1000 (manufactured by TA Instruments) under the following conditions.
Temperature increase rate: 10 ° C / min
Measurement start temperature: 20 ° C
Measurement end temperature: 180 ° C

  The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.

  Specifically, about 5 mg of a sample is precisely weighed, placed in a silver pan, and measured once. A silver empty pan is used as a reference.

  The glass transition point Tg or the melting endothermic peak temperature of the wax is determined from the DSC curve measured under the above conditions.

  In the toner of the present invention, the glass transition temperature of the toner is preferably 50 ° C. or higher in order to suppress embedding of the externally added inorganic fine particles in the toner due to frictional heat in the cleaning portion and to improve fluidity maintenance. Further, it is preferable that the melting point of the wax is 80 ° C. or higher because the untransferred toner is easily loosened, and the magnesium carbonate present on the toner surface acts effectively and the effect of suppressing image blur is easily exhibited.

<Method for Measuring Toner Particle Circularity>
The average circularity of the toner of the present invention is 0.950 or more. When it is 0.950 or more, irregularities on the toner surface due to inorganic fine particles of 70 nm or more and 300 nm or less become effective, which can contribute to maintenance of toner fluidity. The average circularity of the toner is preferably 0.990 or less from the viewpoint of preventing toner cleaning slipping in a low temperature and low humidity environment.

  The average circularity of the toner is measured by a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  The measurement principle of the flow-type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) is to capture flowing particles as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is picked up by a CCD camera, and the picked-up image is image-processed at an image processing resolution of 512 × 512 pixels (0.37 × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image The projected area S, the peripheral length L, etc. are measured.

Next, the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity C is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. And is calculated by the following formula.
Circularity C = 2 × (π × S) ^1/2 / L

  When the particle image is circular, the circularity is 1.000, and the greater the degree of unevenness around the particle image, the smaller the circularity. After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is put in, and about 2 ml of the contamination N is added to the water tank.

  The flow type particle image analyzer equipped with a standard objective lens (10 ×) was used for the measurement, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid.

  The dispersion liquid prepared according to the procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the total count mode in the HPF measurement mode. Then, by setting the binarization threshold at the time of particle analysis to 85% and specifying the analysis particle diameter, the number ratio (%) of particles in the range and the average circularity can be calculated. The average circularity of the toner was set to an equivalent circle diameter of 1.98 μm to 39.96 μm, and the average circularity of the toner was determined.

  In measurement, automatic focus adjustment is performed using standard latex particles (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the examples of the present application, a flow-type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. The measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to a circle equivalent diameter of 1.98 μm or more and less than 39.69 μm.

<Method for Measuring Weight Average Particle Size (D4) of Toner Particles>
The weight average particle diameter (D4) of the toner particles is measured with a precision particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube. Measured data with 25,000 effective measurement channels using the dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) for condition setting and measurement data analysis Analyze and calculate.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software is set as follows.

  In the “Standard measurement method (SOM) change screen” of the dedicated software, set the total count in the control mode to 50000 particles, the number of measurements is 1 and the Kd value is “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.

  In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm or more and 60 μm or less.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.
(2) About 30 ml of the electrolytic aqueous solution is put in a glass 100 ml flat bottom beaker, and "Contaminone N" (nonionic surfactant, anionic surfactant, organic builder pH 7 precision measurement is used as a dispersant therein. About 0.3 ml of a diluted solution obtained by diluting a 10% by weight aqueous solution of a neutral detergent for washing a vessel (made by Wako Pure Chemical Industries, Ltd.) 3 times with ion exchange water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated in a state where the phase is shifted by 180 degrees, and placed in a water tank of an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikkiki Bios Co., Ltd.) having an electrical output of 120 W. A predetermined amount of ion-exchanged water is put, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the analysis / volume statistics (arithmetic average) screen when the graph / volume% is set with the dedicated software is the weight average particle diameter (D4).

<Measurement method of weight average molecular weight of resin>
The molecular weight distribution of the THF soluble part of the resin is measured by gel permeation chromatography (GPC) as follows.

First, the toner is dissolved in tetrahydrofuran (THF) at room temperature over 24 hours. The obtained solution is filtered through a solvent-resistant membrane filter “Maescho Disc” (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in THF is about 0.8% by mass. Using this sample solution, measurement is performed under the following conditions.
Apparatus: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)
Column: Seven series of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 ml

  In calculating the molecular weight of the sample, standard polystyrene resin (for example, trade name “TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F— 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", manufactured by Tosoh Corporation) are used.

<Example of production of amorphous resin A>
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: 71.9 parts by mass (0.20 mol; 100.0 mol% based on the total number of polyhydric alcohols)
-Terephthalic acid: 26.8 parts by mass (0.16 mol; 96.0 mol% based on the total number of polyvalent carboxylic acids)
Titanium tetrabutoxide: 0.5 part by mass The above materials were weighed into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introducing tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 4 hours while stirring at a temperature of 200 ° C.

  Furthermore, the pressure in the reaction vessel was lowered to 8.3 kPa, maintained for 1 hour, and then returned to atmospheric pressure (first reaction step).

Trimellitic anhydride: 1.3 parts by mass (0.01 mol; 4.0 mol% based on the total number of polycarboxylic acids)
Thereafter, the above materials are added, the pressure in the reaction vessel is lowered to 8.3 kPa, and the reaction is performed for 1 hour while maintaining the temperature at 180 ° C. (second reaction step), and the polyester resin A having a weight average molecular weight (Mw) of 5000 Got.

<Example of production of amorphous resin B>
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane: 71.8 parts by mass (0.20 mol; 100.0 mol% based on the total number of polyhydric alcohols)
-Terephthalic acid: 15.0 parts by mass (0.09 mol; 55.0 mol% based on the total number of polycarboxylic acids)
Adipic acid: 6.0 parts by mass (0.04 mol; 25.0 mol% based on the total number of polyvalent carboxylic acids)
Titanium tetrabutoxide: 0.5 part by mass The above materials were weighed into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introducing tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200 ° C.

  Furthermore, the pressure in the reaction vessel was lowered to 8.3 kPa, maintained for 1 hour, and then returned to atmospheric pressure (first reaction step).

Trimellitic anhydride: 6.4 parts by mass (0.03 mol; 20.0 mol% based on the total number of polycarboxylic acids)
Thereafter, the above materials are added, the pressure in the reaction vessel is lowered to 8.3 kPa, and the reaction is performed for 15 hours while maintaining the temperature at 160 ° C. (second reaction step), and the polyester resin B having a weight average molecular weight (Mw) of 100,000. Got.

<Production example of crystalline polyester resin C>
-1,6-hexanediol: 34.5 parts by mass (0.29 mol; 100.0 mol% with respect to the total number of moles of polyhydric alcohol)
-Dodecanedioic acid: 65.5 parts by mass (0.28 mol; 100.0 mol% with respect to the total number of polyvalent carboxylic acids)
The above materials were weighed into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introduction tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 3 hours while stirring at a temperature of 140 ° C.

-Tin 2-ethylhexanoate: 0.5 parts by mass Thereafter, the above materials are added, the pressure in the reaction vessel is lowered to 8.3 kPa, and the reaction is performed for 4 hours while maintaining the temperature at 200 ° C. Got.

<Production example of crystalline polyether resin D>
1,10-decanediol: 100 parts by mass
-25% sulfuric acid: 2 parts by mass The above materials were weighed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introducing tube, and a thermocouple. Next, after replacing the inside of the flask with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 15 hours while stirring at a temperature of 180 ° C. to obtain a crystalline polyether resin D.

<Production Example of Vinyl Resin Polymer E>
-Polyethylene having one or more unsaturated bonds (Mw: 1400, Mn: 850, endothermic peak by DSC: 100 ° C) 20 parts by mass-59 parts by mass of styrene-18.5 parts by mass of acrylate-n-butyl-Acrylonitrile 2.5 parts by mass The above raw materials were charged into an autoclave, and after replacing the interior of the system with nitrogen, the temperature was maintained at 180 ° C. with stirring. In the system, 50 parts by mass of a 2% by mass di-tert-butyl peroxide xylene solution was continuously dropped for 5 hours, and after cooling, the solvent was separated and removed, and the vinyl resin heavy polymer in which the copolymer was grafted onto polyethylene was obtained. Combined E was obtained. The resulting vinyl-based resin polymer E has a softening point of 110 ° C. and a glass transition temperature of 64 ° C. The molecular weight of the polymer E soluble in THF by GPC is a weight average molecular weight (Mw) of 7400, a number average molecular weight. It was (Mn) 2800. A peak corresponding to polyethylene having one or more unsaturated bonds as a raw material was not observed.

<Toner particle production example 1>
Amorphous resin A 72 parts by weight Amorphous resin B 28 parts by weight Crystalline resin C 4 parts by weight Vinyl resin polymer E 5 parts by weight Hydrocarbon wax (peak temperature of maximum endothermic peak 90 ° C) 5 parts by mass I. Pigment Blue 15: 3 5 parts by mass, 3,5-di-t-butylsalicylic acid aluminum compound 0.5 part by mass Using the Henschel mixer (FM-75 type, manufactured by Mitsui Mining Co., Ltd.) with the raw materials shown in the above recipe Then, after mixing at a rotation speed of 1200 rpm and a rotation time of 5 min, the temperature is set so that the discharge temperature becomes 135 ° C., and kneaded by a twin-screw kneader (PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a rotation speed of 350 rpm. did. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material. The obtained coarsely crushed material was finely pulverized with a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.). Thereafter, the finely pulverized product was treated at a rotation speed of 100 s ^{−1 for} 5.5 minutes using a surface modification treatment apparatus (hybridizer, manufactured by Nara Machinery Co., Ltd.) using a mechanical impact force.

  Further, classification was performed using a rotary classifier (200 TSP, manufactured by Hosokawa Micron Corporation) to obtain toner particles. The operating conditions of the rotary classifier (200TSP, manufactured by Hosokawa Micron Corporation) were classified at a classification rotor rotation speed of 3000 rpm. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.965.

<Toner particle production example 2>
In toner particle production example 1, the treatment time by the surface modification treatment apparatus was changed to 3 minutes, and other toners were produced in the same manner as in other prescriptions and production conditions, whereby toner particles 2 were obtained. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.950.

<Toner particle production example 3>
A toner was manufactured in the same manner as in the formulation and manufacturing conditions except that the crystalline resin C was changed to the crystalline resin D in Toner Particle Production Example 1 to obtain toner particles 3. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.965.

<Toner particle production example 4>
Toner particles 4 were obtained in the same manner as in toner particle production example 1, except that the crystalline resin was removed except that C was used. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.965.

<Toner particle production example 5>
Toner particles 5 were obtained in the same manner as in toner particle production example 3, except that the surface modification treatment step was omitted, with the same formulation and production conditions. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.944.

<Toner particle production example 6>
In Toner Particle Production Example 3, the treatment time by the surface modification treatment apparatus was changed to 6 minutes, and other toners were produced in the same manner as in the other prescriptions and production conditions. Thus, toner particles 6 were obtained. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.959.

<Toner particle production example 7>
In toner particle production example 3, the treatment time by the surface modification treatment apparatus was changed to 8 minutes, and other prescriptions and production conditions were similarly used to produce toner, whereby toner particles 7 were obtained. The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.968.

<Examples of magnesium carbonate particle production>
Magnesium carbonate used in this example is magnesium carbonate produced by reacting magnesium hydroxide and carbon dioxide.

  Ethanol / water 50% 500 ml liquid is cooled to -5 to 10 ° C., 400 g magnesium hydroxide is added to form a slurry, carbon dioxide / nitrogen gas 30% from the bottom of the container with vigorous stirring, and a flow rate of 1000 to 3000 ml / min. The reaction was continued until the pH began to drop. At this time, the reaction temperature and the introduction rate of carbon dioxide gas were adjusted to obtain seven types of magnesium carbonate slurries having different particle diameters of 20 to 350 nm. Furthermore, this dispersion was filtered in a low temperature state, sufficiently washed with pure water and then dried to obtain magnesium carbonates 1 to 7.

  Water adjusted to 70 ° C. so as to have a solid content of 10% by mass was added to the obtained magnesium carbonate, and a slurry was obtained using a stirring type disperser. While stirring 1 kg of this magnesium carbonate slurry with a disperser, 2.5 g of saponified stearic acid was added, stirred for 30 minutes, and then press dehydrated. The obtained dehydrated cake was dried and then pulverized to obtain magnesium carbonate particles 1 to 4 and 6 to 8 that were hydrophobized and treated with a fatty acid. Among the obtained magnesium carbonate, about the magnesium carbonate with a particle diameter of 90 nm, what was not surface-treated was kept apart, and this was made into the magnesium carbonate particle 5. FIG.

  The obtained magnesium carbonate particles are shown in Table 1.

<Inorganic fine particles other than magnesium carbonate>
In addition to magnesium carbonate, inorganic fine particles to be externally added to the toner were prepared. Table 2 shows the inorganic fine particles used for external addition of the toner of the present invention.

  Next, a toner in which the above magnesium carbonate 1-8 and inorganic fine particles 1-12 were externally added to the toner particles was produced as follows.

<Toner Production Example 1>
To 6748 g of the obtained toner particles, 42 g of magnesium carbonate particles 4, 105 g of inorganic fine particles 3 and 105 g of inorganic fine particles 11 were added, and the rotation speed was 1800 s with a Henschel mixer (FM-75 type, manufactured by Mitsui Mining Co., Ltd.). ^-1 and mixing at a rotation time of 10 min. Thereafter, the toner 1 was obtained by passing through an ultrasonic vibration sieve having an opening of 54 μm.

  The obtained toner particles had a weight average particle diameter (D4) of 5.7 μm and an average circularity of 0.965. The toner surface coverage with large diameter particles of 70 nm or more and 300 nm or less was 16.2 area%.

  In the differential scanning calorimetry (DSC) measurement of the toner, an endothermic peak derived from the crystalline resin was observed. Further, the glass transition temperature of the toner was measured and found to be 52 ° C.

<Toner Production Examples 2 to 28>
In Toner Production Example 1, toners 2 to 28 were obtained in the same manner as in Toner Production Example 1 except that the types and external addition amounts of magnesium carbonate particles and inorganic fine particles were varied. The glass transition temperature of the toner was 51 to 53 ° C.

  Table 3 shows the material formulation of toners 1 to 28 and the physical properties according to the present invention.

<Example of production of magnetic core particles>
Fe ₂ O ₃ 60.2 mass%
MnCO ₃ 33.9% by mass
Mg (OH) ₂ 4.8% by mass
SrCO ₃ 1.1% by mass
The ferrite raw material was weighed and pulverized and mixed for 2 hours in a dry ball mill using zirconia (φ10 mm) balls.

After pulverization and mixing, firing was performed at 1000 ° C. for 3 hours in the air using a burner-type firing furnace to prepare calcined ferrite. The composition of ferrite is as follows.
(MnO) a (MgO) b (SrO) c (Fe 2 O 3) d
In the above formula, a = 0.39, b = 0.11, c = 0.01, d = 0.50

  Next, after crushing to about 0.5 mm with a crusher, 30 parts by mass of water was added to 100 parts by mass of calcined ferrite using zirconia (φ10 mm) balls, and the mixture was pulverized with a wet ball mill for 2 hours. The slurry was pulverized for 4 hours by a wet bead mill using zirconia beads (φ1.0 mm) to obtain a ferrite slurry.

  To the obtained ferrite slurry, 2.0 parts by mass of polyvinyl alcohol was added as a binder with respect to 100 parts by mass of calcined ferrite, and granulated into spherical particles of about 36 μm with a spray dryer (manufacturer: Okawahara Chemical).

  In order to control the firing atmosphere, firing was performed at 1150 ° C. for 4 hours in an electric furnace under a nitrogen atmosphere (oxygen concentration of 1.00% by volume or less).

  After the aggregated particles were crushed, coarse particles were removed by sieving with a sieve having an opening of 250 μm to obtain magnetic core particles.

<Example of coating resin production>
Cyclohexyl methacrylate monomer 26.8 parts by mass Methyl methacrylate monomer 0.2 part by mass Methyl methacrylate macromonomer 8.4 parts by mass (macromonomer having a methacryloyl group at one end and a weight average molecular weight of 5000)
Toluene 31.3 parts by mass Methyl ethyl ketone 31.3 parts by mass The above materials were added to a four-necked separable flask equipped with a reflux condenser, thermometer, nitrogen introduction tube and stirring device, and nitrogen gas was introduced to sufficiently In a nitrogen atmosphere. Thereafter, the mixture was heated to 80 ° C., 2.0 parts by mass of azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours for polymerization. Hexane was injected into the obtained reaction product to precipitate a copolymer, and the precipitate was filtered off and dried under vacuum to obtain a coat resin.

<Example of magnetic carrier production>
Coat resin 20.0% by mass
Toluene 80.0% by mass
The above materials were dispersed and mixed with a bead mill to obtain a resin liquid. 100 parts by mass of the magnetic core particles were charged into a Nauter mixer, and further, the resin liquid was charged as 2.0 parts by mass as a resin component into the Nauter mixer. The mixture was heated to 70 ° C. under reduced pressure, mixed at 100 rpm, and solvent removal and coating operations were performed over 4 hours. Thereafter, the obtained sample was transferred to a Julia mixer, heat-treated at 100 ° C. for 2 hours in a nitrogen atmosphere, and then classified with a sieve having an opening of 70 μm to obtain a magnetic carrier. The volume distribution standard 50% particle size (D50) of the obtained magnetic carrier was 38.2 μm.

With the above toners 1 to 28 and the magnetic carrier, 0.5 s ^{−1 with} a V-type mixer (V-10 type: Tokuju Seisakusho Co., Ltd.) and a rotation time of 5 min so that the toner concentration becomes 10.0% by mass. Two-component developers 1 to 28 were obtained by mixing.

  The performance evaluation shown below was performed using the obtained developers 1 to 28.

<Image Flow Evaluation 1>
Two-component developer 1 to 28 was put into the cyan toner developer of Canon full color copier imageRUNNER ADVANCE C9080PRO, and 3000 sheets of image output durability tests were conducted in a high temperature and high humidity environment (30 ° C / 80% Rh). went. The output image was a monochrome 4A horizontal, 2 cm wide, vertical band image of cyan, and was adjusted so that the reflection density measured with a cyan X-Rite reflection densitometer on paper was 1.400. As the evaluation paper, copy paper GF-C081 (A4, basis weight 81.4 g / m2, sold from Canon Marketing Japan Inc.) was used.

  After outputting 3000 sheets, leave it for 24 hours, replace the charging device with a new one, output a full-tone halftone image (reflection density 0.800) with dots, and image of the boundary position between the durable ruled vertical ruled line part and the non-image part The density was measured at 10 locations, the average value was calculated, and the difference in image density was evaluated. When the image flow occurs, the size of the developed dot decreases, and the density of the halftone image decreases.

(Evaluation criteria: Density difference due to reduced density at the non-image endurance of halftone images)
A: Less than Δ0.010 (Excellent)
B: Δ0.010 or more and less than Δ0.020 (very good)
C: Δ0.020 or more and less than Δ0.030 (excellent)
D: Δ0.030 or more and less than Δ0.040 (slightly better)
E: Δ0.040 or more and less than Δ0.080 (prior art level)
F: Δ0.080 or more or overall streak-like image flow occurs (inferior to conventional)

<Image flow evaluation 2>
Two-component developer 1 to 28 was put into the cyan toner developer of Canon full color copier imageRUNNER ADVANCE C9080PRO, and 3000 sheets of image output durability tests were conducted in a high temperature and high humidity environment (30 ° C / 80% Rh). went. The output image was a monochrome 4A horizontal, 2 cm wide, vertical band image of cyan, and was adjusted so that the reflection density measured with a cyan X-Rite reflection densitometer on paper was 1.400. As the evaluation paper, copy paper GF-C081 (A4, basis weight 81.4 g / m ² , sold by Canon Marketing Japan Inc.) was used.

  After outputting 150,000 sheets, leave it for 24 hours, replace the charging device with a new one, output a full-tone halftone image (reflection density 0.800) with dots, and show the boundary position between the durable image vertical ruled line part and the non-image part The image density was measured at 10 locations, the average value was calculated, and the image density difference was evaluated. It was evaluated how much the density difference of the image flow evaluation 1 could be maintained in the long range durability. Specifically, it was calculated how much the density difference Δ spread after outputting 150,000 sheets of images after outputting 3000 sheets of images.

(Evaluation criteria: Enlargement ratio of density difference due to density down of durable non-image position of halftone image)
A: Less than 5% (Excellent)
B: 5% or more and less than 10% (very good)
C: 10% or more and less than 20% (excellent)
D: 20% or more and less than 30% (a little better)
E: 30% or more and less than 50% (prior art level)
F: 50% or more or overall streak-like image flow generation (inferior to conventional)

<Photoconductor cleaning evaluation>
150,000 image output durability test in a high-temperature and high-humidity environment (30 ° C / 80% Rh) by introducing two-component developer 1-28 into the cyan toner developer of Canon full color copier imageRUNNER ADVANCE C9080PRO Went. The output image was a horizontal band image with a width of 1 cm and a width of 4 cm of cyan in the monochrome mode, and the cyan reflection density on the paper was adjusted to 1.400. As the evaluation paper, copy paper GF-C081 (A4, basis weight 81.4 g / m2, sold from Canon Marketing Japan Inc.) was used.

  After 150,000 sheets were output, the charging device was removed and the toner adhering to the charging device was collected with a transparent tape and attached to unused evaluation paper, and 9 points were measured with a fogging reflection densitometer, and the average value was calculated. The reflection density when a tape from which toner was not collected was attached was used as a reference.

(Evaluation criteria: amount of toner fog on the charging device)
A: Less than 0.2% (excellently excellent)
B: 0.2% or more and less than 0.5% (very good)
C: 0.5% or more and less than 1.0% (excellent)
D: 1.0% or more and less than 2.0% (slightly better)
E: 2.0% or more and less than 5.0% (prior art level)
F: 5.0% or more (inferior to conventional)

  Table 4 shows the evaluation results of Examples 1 to 21 and Comparative Examples 1 to 7 in which the two-component developers 1 to 28 were evaluated by the above evaluation methods and standards. In Comparative Examples 1 to 7, the results of durability evaluation of the image flow and cleaning evaluation of the photosensitive member were too bad, and the image output durability was stopped halfway.

  As shown in the above results, the toner has an average circularity of 0.950 or more, and the toner has magnesium carbonate particles having a number average particle diameter of 30 nm to 300 nm and a new Mohs hardness of 6 to 13 inclusive. When the toner surface coverage with the inorganic fine particles A having a particle diameter of 70 nm or more and 300 nm or less is 5.0 area% or more, it is possible to obtain a toner capable of uniformly preventing image flow.

  Further, the content of the magnesium carbonate particles in the toner is 0.02 mass% or more and 1.00 mass% or less, and the content of the inorganic fine particles A in the toner is equal to the content mass of the magnesium carbonate particles in the toner. On the other hand, when it is 0.5 times or more and 8.0 times or less, durability of the image flow uniformity prevention performance can be provided.

  In addition, by including crystalline polyester resin or crystalline polyether resin in the binder resin in the toner, it is possible to improve the photoconductor cleaning property of transfer residual toner in high-temperature and high-humidity environment in toner containing calcium carbonate particles. Can be made.

Claims (4)

A toner having toner particles and inorganic fine particles containing a binder resin, a colorant and a wax,
The toner has an average circularity of 0.950 or more,
The inorganic fine particles include magnesium carbonate particles and inorganic fine particles A having a new Mohs hardness of 6 to 13,
The magnesium carbonate particles have a number average diameter of primary particles of 30 nm to 300 nm,
The toner is characterized in that the toner surface coverage by the inorganic fine particles A having a particle diameter of 70 nm or more and 300 nm or less is 5.0 area% or more.   The toner according to claim 1, wherein the inorganic fine particles A are metal oxide fine particles selected from silicon oxide, titanium oxide, aluminum oxide, cerium oxide, or zirconium oxide. The magnesium carbonate particles have a content in the toner of 0.02% by mass or more and 1.00% by mass or less,
3. The toner according to claim 1, wherein the content of the inorganic fine particles A in the toner is 0.5 to 8.0 times the mass of the magnesium carbonate particles in the toner.   The toner according to any one of claims 1 to 3, wherein the binder resin contains a crystalline polyester resin or a crystalline polyether resin.