JP6532315B2 - toner - Google Patents

Description

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

In recent years, with the widespread use of electrophotographic full-color copiers, the demand for high-speed printing and energy saving measures is further increasing. In order to cope with high-speed printing, techniques for melting the toner more quickly in the fixing process are being studied. Further, as a measure for energy saving, in order to reduce the power consumption in the fixing process, a technology for fixing the toner at a lower fixing temperature has been considered.
In order to cope with high-speed printing and to improve the low-temperature fixability of the toner, there is a method of using a binder resin having a sharp melting property and lowering the glass transition point and the softening point of the binder resin of the toner. In recent years, many toners containing a crystalline polyester resin have been proposed as a resin having sharp melt properties. It is known that the state of the crystalline polyester present in the toner greatly affects the properties of the toner.

Patent Document 1 discloses a toner having a maximum diameter of 0.5 μm or more and 2 μm or less of domains of a crystalline polyester resin in a cross section of a toner having a core particle and a shell layer. According to this, it is supposed that the low temperature fixability and the suppression of filming can be compatible. Patent Document 2 discloses a toner having core particles and an outer shell, in which crystalline polyester is finely dispersed in the core particles in a string-like state in which the ratio of length La to width Lb is 10 or more. It is done. As a result, low temperature fixability and heat resistant storage stability can be compatible, and low temperature fixability is achieved by the effect of the crystalline polyester.
On the other hand, it is known that crystalline polyesters have a low electrical resistance and tend to have lower chargeability than toners containing crystalline polyesters as compared to toners not containing crystalline polyesters. Various investigations have been made to devise external additives for use in toners for the purpose of improvement. Patent Document 3 uses non-spherical silica in the form of secondary particles in which primary particles of silica are coalesced together, which is excellent in storability in a high temperature and high humidity environment, and has good flowability, transferability and low temperature fixability. Excellent toners are disclosed.

JP, 2009-229920, A JP 2012-18391 A JP, 2014-178528, A

According to the investigations of the present inventors, the toners of Patent Documents 1 and 2 maintain charge stability in a high temperature and high humidity environment, particularly, maintain durability in a high temperature and high humidity environment and maintain chargeability after being left in a high temperature and high humidity environment. That was not enough.
Further, in the invention of Patent Document 3, the chargeability of the toner decreases when it is durable at a high printing ratio in a high temperature and high humidity environment or left in a high temperature and high humidity environment, and the fog on the image white area is thereby caused. It has not reached the level sufficiently and improvement is required.
An object of the present invention is to provide a toner that solves the above-mentioned problems. Specifically, it is to provide a toner having durability stability in a high temperature and high humidity environment, maintaining chargeability even after standing in a high temperature and high humidity environment, and reducing density fluctuation and fog.

The toner of the present invention, the toner particles containing a binder resin, a toner having an inorganic fine powder as an external additive,
The binder resin contains amorphous polyester and crystalline polyester,
The inorganic fine powder contains strontium titanate fine powder,
The number average diameter of primary particles of the strontium titanate fine powder is 30 nm or more and 300 nm or less,
The strontium titanate fine powder is a particle having a cubic and / or rectangular solid particle shape, and having a perovskite crystal structure,
In a transmission electron microscope (TEM) image obtained by binarizing the cross-sectional images of I Ri obtained that the toner in observation,
The number average particle diameter Dc of the major axis length of the crystalline polyester is 40 nm or more and 300 nm or less, observed in a needle shape defined as follows from the toner surface to a depth of 0.30 μm:
In the frequency distribution of the major axis length of the crystalline polyester observed in the needle shape defined as follows to a depth of 0.30 μm from the toner surface, the maximum value exists at 50 nm or more and 290 nm or less It is a feature toner.
(Needle-like)
The short axis length is 25 nm or less, the aspect ratio (long axis length / short axis length) is 3 or more, and when central points in the short axis direction at both ends in the long axis direction of crystals are connected by straight lines It refers to a shape in which the deviation of the crystal outline from the straight line is within a length within 100% of the crystal minor axis length.

  According to the present invention, it is possible to provide a toner having durability stability in a high temperature and high humidity environment, maintaining chargeability even after being left in a high temperature and high humidity environment, and reducing density fluctuation and fog.

Example of toner cross section by transmission electron microscope of toner of the present invention Diagram showing major axis length and uniaxial length of crystalline polyester in toner cross section Frequency distribution of major axis length of crystalline polyester of toner used in Example 1

The toner of the present invention is a toner having toner particles containing a binder resin and an inorganic fine powder,
The binder resin contains amorphous polyester and crystalline polyester,
The inorganic fine powder contains strontium titanate fine powder,
The number average diameter of primary particles of the strontium titanate fine powder is 30 nm or more and 300 nm or less,
The strontium titanate fine powder has a cubic and / or rectangular solid particle shape, and has a perovskite crystal structure,
In the cross section of the toner by transmission electron microscope (TEM) observation,
The number average particle diameter Dc of the major axis length of the crystalline polyester observed in a needle shape from the toner surface to a depth of 0.30 μm is 40 nm or more and 300 nm or less,
The toner according to the present invention is a toner having a maximum value of 50 nm or more and 290 nm or less in the frequency distribution of the major axis length of the crystalline polyester observed in a needle shape up to a depth of 0.30 μm from the toner surface.

The inventors of the present invention, after externally adding a specific strontium titanate fine powder to toner particles in which the crystalline state of crystalline polyester in the toner is controlled to a specific range, are left in a high temperature and high humidity environment. It has been found that the chargeability is improved, and the present invention has been made.
The inventors consider the mechanism as follows.
When the toner is agitated in the developing device, a developing bias is applied. Based on the potential difference, it is considered that the negative charge generated by friction due to stirring is transferred to the strontium titanate fine powder on the toner surface as a relatively low-resistance crystalline polyester as a pass. The relative dielectric constant of strontium titanate is about 300, which is higher than that of a general external additive silica fine powder, and it seems that a capacitor-like function appears and charge is accumulated on the surface of strontium titanate. . Therefore, it is considered that the chargeability is maintained even after being left in a high temperature and high humidity environment, and the density fluctuation and the fog on the white part are suppressed.

The toner of the present invention contains strontium titanate fine powder as inorganic fine powder, and the primary particles of the strontium titanate fine powder have a number average diameter of 30 nm or more and 300 nm or less. Further, the strontium titanate fine powder has a cubic and / or rectangular solid particle shape, and has a perovskite crystal structure.
The inventors of the present invention have found that the particle shape of the strontium titanate fine powder is important for the negative charge to move from the needle-like crystalline polyester present in the vicinity of the strontium titanate fine powder to the strontium titanate fine powder. It became clear in the examination of

As a method of producing the strontium titanate fine powder, there is also a method of pulverizing after being subjected to a sintering step, but the fine powder obtained in this way is in the form of indeterminate form or aggregate of primary particles. The strontium titanate fine powder of the present invention is prepared, for example, by adding a hydroxide of strontium to a dispersion of titania sol obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate, It can synthesize | combine by heating to reaction temperature.
Since the strontium titanate fine powder produced in this manner has a cubic / rectangular shape, charge transfer from crystalline polyester to strontium titanate is likely to occur. Although the detailed reason is unknown, it is considered that the strontium titanate fine powder of the present invention derives from its cubic / rectangular shape, and the crystal structure is uniform from the inside to the outermost surface. Therefore, it is considered that the crystal structure has a crystal structure that easily receives a negative charge from the crystalline polyester and easily accumulates a charge as compared with the strontium titanate fine powder produced by the sintering method.

  The number average diameter of primary particles of the strontium titanate fine powder needs to be 30 nm or more and 300 nm or less. When the number average diameter of the primary particles of the strontium titanate fine powder is in this range, negative charge from the crystalline polyester is easily received, and charge accumulation effectively occurs. If it is less than 30 nm, the charge accumulation effect is low and the chargeability after leaving in a high temperature and high humidity environment tends to decrease, and if it exceeds 300 nm, the adhesion to toner particles becomes weak and the charge accumulation effect also weakens. Durability in high temperature and high humidity environment tends to decrease. More preferably, it is 60 nm or more and 140 nm or less.

The strontium titanate fine powder used in the present invention is prepared, for example, by adding strontium hydroxide to a dispersion of titania sol obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate. It can be synthesized by heating to the reaction temperature. By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having a good degree of crystallinity and particle size can be obtained.
Further, in order to remove ions adsorbed to the titania sol particles, it is preferable to add an alkaline substance such as sodium hydroxide to the dispersion of the titania sol. At this time, in order to prevent sodium ions and the like from being adsorbed on the surface of the hydrous titanium oxide, it is preferable to set the pH of the slurry not to 7 or more. The reaction temperature is preferably 60 ° C. to 100 ° C. In order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C./hour or less, and the reaction time is preferably 3 to 7 hours.
The particle size of the strontium titanate fine powder can be adjusted by changing the pH of the hydrous titanium oxide slurry and the amount of strontium hydroxide to be added.
The strontium titanate fine powder thus obtained has a perovskite crystal structure.

The strontium titanate fine powder used in the present invention has an adhesive property to toner particles that its surface is hydrophobized by fatty acid or its metal salt, silicone oil, silane coupling agent, titanium coupling agent, etc. Is preferred in that it is easy to carry out charge accumulation.
The content of the strontium titanate fine powder in the toner is 0.1 parts by mass or more with respect to 100 parts by mass of toner particles, from the viewpoint of achieving both the charge accumulation effect and suppression of separation from the toner surface. 10.0 mass parts or less are preferable, and 0.2 mass parts or more and 3.0 mass parts or less are more preferable.
The toner particles and the inorganic fine powder may be mixed using known mixers such as Henschel mixer, Mechano hybrid (manufactured by Nippon Coke Co., Ltd.), Super mixer, Nobilta (manufactured by Hosokawa Micron Co.), etc. The device is not limited.

The toner of the present invention is characterized by containing a crystalline polyester.
In the present invention, the crystalline polyester is a polyester whose endothermic peak is observed in differential scanning calorimetry (DSC).
In the crystalline polyester of the present invention, the major axis length of the crystalline polyester observed in a needle shape from the toner surface to the depth of 0.30 μm (toner surface layer) in the cross section of the toner by transmission electron microscopy (TEM) observation Number average particle diameter Dc of 40 nm or more and 300 nm or less,
In the frequency distribution of the major axis length of the crystalline polyester observed in a needle shape from the toner surface to a depth of 0.30 μm, it is important that the maximum value is 50 nm or more and 290 nm or less.

  In the present invention, “needle” is a shape having a long straight shape with a high degree of straightness, a uniaxial length of 25 nm or less, an aspect ratio of 3 or more, and minor axis directions at both ends in the major axis direction of the crystal. When the central points are connected by a straight line, it means that the deviation of the crystal outline from the straight line is within the length of 100% or less of the minor axis length of the crystal. It is presumed that the movement of charge inside the toner occurs smoothly because the crystals are needle-like.

  The present inventors control the number average particle diameter Dc of the major axis length of the crystalline polyester observed in needle shape from the toner surface to the depth of 0.30 μm (toner surface layer) in the range of 40 nm to 300 nm. It has been found that the charge leakage from the toner surface is suppressed and the transfer of negative charge to strontium titanate occurs efficiently. When the number average particle size is less than 40 nm, charge transfer to the strontium titanate fine powder is less likely to occur, and the charge accumulation effect is less likely to be exhibited. When the number average particle size exceeds 300 nm, the crystalline polyester is easily exposed to the toner surface, and the negative charge leaks from the toner surface better than the transfer of the negative charge to the strontium titanate fine powder, and the negative charge accumulation effect Hard to be born. More preferably, it is 50 nm or more and 200 nm or less.

The crystalline polyester having a major axis length of 50 nm or more and 290 nm or less is likely to work effectively for the movement of negative charge, so the maximum value in the frequency distribution of the major axis length of the crystalline polyester observed in needle shape on the toner surface Is important in the present invention to be present at 50 nm or more and 290 nm or less. Preferably it is 50 nm or more and 250 nm or less.
The strontium titanate fine powder of the present invention is added to the surface of toner particles as an external additive. Therefore, in the present invention, the distribution of the major axis length of the crystalline polyester observed in needle shape up to the depth of 0.30 μm from the toner surface which largely contributes to the charge transfer to the strontium titanate fine powder is important in the present invention.

As a method of making the number average particle diameter Dc of the major axis length of the crystalline polyester observed in needle shape up to the depth of 0.30 μm from the toner surface be in the range of 40 nm to 300 nm, the following methods are available. .
By changing the acid / alcohol monomer used for the synthesis of the amorphous polyester or the crystalline polyester, the dispersibility and compatibility of the crystalline polyester with the amorphous polyester can be changed, so that the major axis length can be changed. .
In the case of producing the toner by the pulverization method, the major axis length can be changed by changing the discharge temperature and the cooling rate after the melt-kneading. When the toner is produced in a liquid phase such as an emulsion aggregation method or a dissolution suspension method, the major axis length of the crystalline polyester can be changed by changing the temperature at the time of toner granulation.
Further, the major axis length of the crystalline polyester present to a depth of 0.30 μm can also be changed by heat treating the obtained toner particles.
Further, the maximum value of the frequency distribution of the major axis length of the crystalline polyester of the toner surface layer can be controlled by changing the cooling rate after the melt-kneading when the toner is produced by the pulverization method. When a toner is produced in a liquid phase such as an emulsion aggregation method or a dissolution suspension method, it can be controlled by changing the granulation time of the toner. When the toner particles obtained are heat-treated, the maximum value of the frequency distribution of the major axis length of the crystalline polyester of the toner surface layer can be controlled also by changing the processing temperature and the processing time.

The toner of the present invention is characterized by containing amorphous polyester and crystalline polyester as a binder resin.
(Amorphous polyester)
As the non-crystalline polyester resin used in the present invention, conventional ones composed of an alcohol component and an acid component can be used, and both components are exemplified below.
As alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexene dimethanol, hydrogenated bisphenol A, bisphenol derivatives represented by the following formula (1). . Preferred are bisphenols such as hydrogenated bisphenol A and bisphenol derivatives represented by the following formula (1).

[In the Formula, R is an ethylene group or a propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 1 to 10. ]
Furthermore, as the alcohol component, polyhydric alcohols such as glycerin, pentaerythritol, sorbit, sorbitan, and oxyalkylene ethers of novolac type phenol resin can be mentioned.

  On the other hand, as the divalent carboxylic acid constituting the amorphous polyester resin, benzenedicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or its anhydride; succinic acid, adipic acid, sebacic acid, azeline There may be mentioned alkyl dicarboxylic acids such as acids or their anhydrides. Furthermore, there may be mentioned succinic acid or an anhydride thereof substituted with an alkyl group or alkenyl group having 6 to 18 carbon atoms; fumaric acid, maleic acid, citraconic acid, unsaturated dicarboxylic acids such as itaconic acid or anhydrides thereof, etc. Be Further, polycarboxylic acids such as trimellitic acid, pyromellitic acid, 1,2,3,4-butanetetracarboxylic acid, benzophenonetetracarboxylic acid and anhydrides thereof can be mentioned.

The amorphous polyester in the present invention is obtained by condensation polymerization of an alcohol component containing 80 mol% or more (more preferably 90 mol% or more and 100 mol% or less) of propylene oxide adduct of bisphenol and a carboxylic acid component. Are preferred. Further, it is preferable that the polyester is an amorphous polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing an aliphatic dicarboxylic acid having 4 to 18 (more preferably 6 to 12) carbon atoms. In addition, the average addition mole number of the propylene oxide adduct to the bisphenols is preferably 1.6 mol or more and 3.0 mol or less, and more preferably 1.6 mol or more and 2.6 mol or less.
Increasing the proportion of the propylene oxide adduct is preferable from the viewpoint of enhancing the hydrophobicity of the amorphous resin, improving the compatibility of the crystalline polyester resin, and stabilizing the charge amount even after being left in a high temperature and high humidity environment. When the average addition mole number of the propylene oxide adduct is in the above range, the dispersibility of the crystalline polyester can be improved, and it is more preferable from the viewpoint of stabilizing the image density after being left in a high temperature and high humidity environment.
Further, by using an amorphous polyester using a carboxylic acid component containing an aliphatic dicarboxylic acid having 4 or more and 18 or less carbon atoms, the crystalline polyester in the toner can be obtained by the strong affinity of this portion with the crystalline polyester. Dispersion is improved. This is preferable because fog is further suppressed. As a molar ratio with respect to the carboxylic acid component of C4 or more and 18 or less aliphatic dicarboxylic acid, it is more preferable that it is 6 mol% or more and 40 mol% or less.

As an aliphatic dicarboxylic acid having 4 to 18 carbon atoms, in addition to the above, for example, alkyldicarboxylic acids such as tetradecanedioic acid and octadecanedioic acid, anhydrides thereof, lower alkyl esters and the like can be mentioned. In addition, compounds having a structure in which a part of their main chain is branched by an alkyl group such as a methyl group, an ethyl group or an octyl group, or an alkylene group can be mentioned. Also included are alicyclic dicarboxylic acids such as tetrahydrophthalic acid.
The above amorphous polyester resin is any of commonly used catalysts such as tin, titanium, antimony, manganese, nickel, zinc, lead, iron, metals such as iron, magnesium, calcium, germanium and the like, and metal-containing compounds thereof Can also be used.
The non-crystalline polyester resin preferably has an acid value of 1 mg KOH / g to 10 mg KOH / g from the viewpoint of charge stability.

Further, the non-crystalline polyester of the toner according to the present invention contains a low-softening point non-crystalline polyester A and a high-softening point non-crystalline polyester B to achieve both low temperature fixability and hot offset resistance. Preferred.
Low temperature fixability and hot offset resistance that the content ratio (A / B) of the low softening point amorphous polyester A to the high softening point amorphous polyester B is 60/40 to 90/10 on a mass basis It is preferable from the viewpoint of sex.
The softening point of the amorphous polyester A having a low softening point is preferably 70 ° C. or more and 100 ° C. or less from the viewpoint of achieving both the storage stability of the toner and the low-temperature fixability.
It is preferable from the viewpoint of hot offset resistance that the softening point of the amorphous polyester B having a high softening point is 110 ° C. or more and 180 ° C. or less.
In the toner of the present invention, when the content of the non-crystalline polyester is 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of toner particles, it is easy to simultaneously achieve excellent low temperature fixability and hot offset resistance. More preferable.

<Other binder resin>
As the binder resin used in the toner of the present invention, the following polymers can be used in addition to the above-mentioned amorphous polyester for the purpose of improving the pigment dispersibility, and improving the charging stability and blocking resistance of the toner. It is also possible to add it in the quantity which does not inhibit the effect of the present invention.
In the present invention, when the dispersibility of the releasing agent and the pigment is improved, the dispersibility of the fine crystals of the crystalline polyester on the surface is improved, and therefore, it is preferable that the toner contains another resin as a dispersant.

  As other resin used for the binder resin of the toner of this invention, the following resin is mentioned, for example. Monomers of styrene and substitution products thereof, such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene -Acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether Copolymers, Styrene copolymers such as styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic resin , Methacryl tree , Polyvinyl acetate, silicone resins, polyester resins, polyurethane, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone - indene resins, petroleum resins, and the like.

<Crystalline polyester resin>
The crystalline polyester resin of the present invention is preferably obtained by subjecting a monomer composition containing an aliphatic diol and an aliphatic dicarboxylic acid as main components to a polycondensation reaction. Among them, an aliphatic diol having 6 or more and 12 or less carbon atoms and a fat having 6 or more and 12 or less carbon atoms as the monomer constitution of the crystalline polyester resin from the viewpoint of achieving both low temperature fixability and storability at higher levels. It is preferred to use family dicarboxylic acids.
The aliphatic diol is not particularly limited, but is preferably a linear (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, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene Examples include glycol and neopentyl glycol. Among these, particularly preferred are linear aliphatics such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and α, ω-diols.
Among the above alcohol components, preferred is an alcohol selected from aliphatic diols having 50% by mass or more, and more preferably 70% by mass or more, having 2 to 22 carbon atoms (preferably 6 to 12 carbon atoms). More preferably, the alcohol component is an alcohol in which 80% by mass or more is selected from aliphatic diols having 6 to 12 carbon atoms.

  In the present invention, polyhydric alcohol monomers other than the above aliphatic diols can also be used. Among the polyhydric alcohol monomers, examples of the dihydric alcohol monomer include aromatic alcohols such as polyoxyethylenated bisphenol A and polyoxypropyleneated bisphenol A; 1,4-cyclohexanedimethanol and the like. Moreover, as a polyhydric alcohol monomer of trivalent or more among the polyhydric alcohol monomers, aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; pentaerythritol, dipentaerythritol, tripentaerythritol Fats such as 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and the like Family alcohol and the like.

On the other hand, the aliphatic dicarboxylic acid is not particularly limited, but is preferably a linear (more preferably linear) aliphatic dicarboxylic acid. As a specific example, oxalic acid, malonic acid,
Succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, glutaconic acid, azelaic acid, sebacic acid, nonane dicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citraconic Examples thereof include acids and itaconic acids, and also include those obtained by hydrolyzing these acid anhydrides or lower alkyl esters.
In the present invention, a carboxylic acid selected from aliphatic dicarboxylic acids having 2 to 22 carbon atoms (preferably 6 to 12 carbon atoms) of preferably 50% by mass or more, more preferably 70% by mass or more among the carboxylic acid components. It is an acid. More preferably, among the above-mentioned carboxylic acid components, 80% by mass or more is a carboxylic acid selected from aliphatic dicarboxylic acids having 6 to 12 carbon atoms.

  In the present invention, polyvalent carboxylic acids other than the above aliphatic dicarboxylic acids can also be used. Among the other polyvalent carboxylic acid monomers, as a divalent carboxylic acid, aromatic carboxylic acids such as isophthalic acid and terephthalic acid; aliphatic carboxylic acids of n-dodecylsuccinic acid and n-dodecenylsuccinic acid; cyclohexanedicarboxylic acid Alicyclic carboxylic acids such as acids and the like, and acid anhydrides or lower alkyl esters thereof 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, 1, Aromatic carboxylic acids such as 2,4-naphthalenetricarboxylic acid, 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 can be mentioned, and these acid anhydrides or derivatives such as lower alkyl esters are also included.

  In the present invention, the content of the crystalline polyester resin in the toner particles is preferably 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the non-crystalline polyester resin. The amount is more preferably 1 part by mass or more and 15 parts by mass or less from the viewpoint of achieving both low temperature fixability and chargeability.

<Colorant>
Examples of the colorant that can be contained in the toner include the following.
Examples of the black colorant include carbon black; those toned in black using a yellow colorant, a magenta colorant and a cyan colorant. Although a pigment may be used alone as the colorant, 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 in combination.
As pigments for magenta toners, the following may be mentioned. 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, 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, 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. Disperse thread 9; C.I. I. Solvent violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disperse Violet 1, C.I. I. 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 pigments for cyan toner include the following. C. I. Pigment blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; C.I. I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted to a phthalocyanine skeleton.
As dyes for cyan toner, C.I. I. There is a solvent blue 70.
Examples of pigments for yellow toners 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.
As dyes for yellow toner, C.I. I. There is a solvent yellow 162.
The amount of the colorant used is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

(wax)
Examples of the wax used for the toner of the present invention include the following. Low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymer, microcrystalline wax, paraffin wax, hydrocarbon wax such as Fischer-Tropsch wax; oxide of hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof Waxes based on fatty acid esters such as carnauba wax; Deoxidized fatty acid esters such as deacidified carnauba wax partially or entirely.
Further, the following may be mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brashidic acid, eleostearic acid and valinaric acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnavir alcohol, seryl alcohol Saturated alcohols such as melysyl alcohol; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, montanic acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnavir alcohol Esters with alcohols such as ceryl alcohol and melysyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide and lauric acid amide; methylenebisstearic acid amide, ethylene Saturated fatty acid bisamides such as scapric acid 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 Unsaturated fatty acid amides such as dioleyl 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 Aliphatic metal salts such as magnesium stearate (generally referred to as metal soaps); waxes grafted with aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; behenine Acid monoglyceride Una fatty acids with polyhydric alcohols of the partial ester; methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable fats and oils.

Among these waxes, paraffin waxes, hydrocarbon-based waxes such as Fischer-Tropsch wax, or fatty acid ester-based waxes such as carnauba wax are preferable from the viewpoint of improving low-temperature fixability and hot offset resistance. In the present invention, hydrocarbon-based waxes are more preferable in that the hot offset resistance is further improved.
The content of the wax is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Charge control agent)
The toner can also contain a charge control agent, if necessary. Known charge control agents may be used as the charge control agent contained in the toner, but in particular, a metal compound of an aromatic carboxylic acid which is colorless and capable of stably holding a fixed charge amount with high charge speed of the toner is preferable.
As negative charge control agents, metal compounds of salicylic acid, metal compounds of naphthoic acid, metal compounds of dicarboxylic acid, polymeric compounds having sulfonic acid or carboxylic acid in the side chain, sulfonic acid salt or sulfonated ester compound in the side chain A polymer type compound, a polymer type compound having a carboxylic acid salt or a carboxylic acid ester compound in a side chain, a boron compound, a urea compound, a silicon compound, calixarene, etc. may be mentioned. Examples of positive charge control agents include quaternary ammonium salts, polymer type compounds having the quaternary ammonium salt in the side chain, guanidine compounds and imidazole compounds. The charge control agent may be internally or externally added to the toner particles. The amount of charge control agent added 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.

(Inorganic fine powder)
The toner of the present invention may also contain other inorganic fine powder, if necessary, in addition to the aforementioned strontium titanate. The inorganic fine powder may be internally added to the toner particles or may be mixed with the toner particles as an external additive. As the external additive, inorganic fine powders such as silica, titanium oxide and aluminum oxide are preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof.
As the external additive for improving the flowability, an inorganic fine powder having a specific surface area of 50 m ² / g or more and 400 m ² / g or less is preferable, and for stabilization of durability, the specific surface area is 10 m ² / g or more and 50 m It is preferable that it is an inorganic fine powder of ² / g or less. In order to make flowability improvement and durability stability compatible, you may use together the inorganic fine powder whose specific surface area is the said range.
The external additive is preferably used in an amount of 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the toner particles. A known mixer such as a Henschel mixer can be used to mix the toner particles with the external additive.

<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 is possible to mix it with a magnetic carrier and use it as a two-component developer, and an image stable over a long period of time Is preferable in that
As the magnetic carrier, for example, iron powder whose surface is oxidized or unoxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, etc. In general, a magnetic substance-dispersed resin carrier (so-called resin carrier) containing magnetic particles such as alloy particles of oxide, oxide particles and ferrite, and a magnetic substance and a binder resin which holds the magnetic substance in a dispersed state You can use one.
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 preferably 2% by mass or more and 15% by mass or less as the toner concentration in the two-component developer More preferably, good results are obtained when the content is 4% by mass or more and 13% by mass or less.

<Manufacturing method>
As a method of producing toner particles, although it can be obtained by a known method, it is easy to control the major axis length of crystalline polyester within the scope of the present invention, and it is necessary to use a binder resin and Accordingly, it is more preferable to melt and knead other materials such as colorants and waxes, and to grind and classify after cooling the kneaded material.
Hereinafter, an example of a toner production procedure in the pulverization method will be described.

In the raw material mixing step, other components such as, for example, a binder resin, a wax, a colorant, and a charge control agent are weighed and mixed in predetermined amounts as materials constituting toner particles.
Examples of the mixing apparatus include a double con mixer, a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a mechano hybrid (manufactured by Nippon Coke Industry Co., Ltd.).
Next, the mixed material is melt-kneaded to disperse wax and the like in the binder resin. The kneading discharge temperature is preferably 100 to 155 ° C. In the melt-kneading process, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous-type kneader can be used, and a single- or twin-screw extruder becomes the mainstream because of the superiority of continuous production. ing. For example, a KTK type twin screw extruder (made by Kobe Steel, Ltd.), a TEM type twin screw extruder (made by Toshiba Machine Co., Ltd.), a PCM kneader (made by Ikegai Iron Works Co., Ltd.), a twin screw extruder (Kyshi K. K. And Ko Kneader (manufactured by Bus Co., Ltd.) and Niedex (manufactured by Japan Coke Industry Co., Ltd.). Furthermore, the resin composition obtained by melt-kneading may be rolled by a two-roll mill or the like, and may be cooled by water or the like in the cooling step to control the cooling rate of the melt-kneaded product. The cooling rate is 5 to 40 ° C./min. Is preferred.

The cooled resin composition is then ground to the desired particle size in the grinding step. In the pulverizing step, for example, after coarsely pulverizing with a pulverizer such as crusher, hammer mill, feather mill, etc., for example, cryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), superrotor (manufactured by Nisshin Engineering Co., Ltd.), turbo mill Fine pulverization is carried out using a fine crusher (manufactured by Freund Turbo Co.) or an air jet method.
After that, if necessary, classification of inertial classification type elbow jet (made by Nittetsu Mining Co., Ltd.), centrifugal force classification type Turboplex (made by Hosokawa Micron), TSP separator (made by Hosokawa Micron), Faculty (made by Hosokawa Micron), etc. The resultant is classified using a machine or a sieving machine to obtain a classified product (toner particles). Among them, the faculty (made by Hosokawa Micron) can perform the spheroidizing process of the toner particles simultaneously with the classification, and is preferable in terms of the improvement of the transfer efficiency.
In addition, if necessary, after pulverization, a hybridization system (manufactured by Nara Machinery Co., Ltd.), a mechano fusion system (manufactured by Hosokawa Micron), a faculty (manufactured by Hosokawa Micron), and Meteo Rainbow MR Type (manufactured by Nippon Pneumatic Md.) Are used. Surface treatment of toner particles, such as spheroidizing treatment, can also be performed.

  The average circularity of the toner is preferably 0.930 or more and 0.985 or less from the viewpoint of achieving both improvement in transferability and cleaning performance. When the toner is produced by a pulverization method, the toner having the above-mentioned average circularity can be produced by subjecting the toner particles to surface treatment such as spheroidizing treatment or surface treatment by heat treatment.

Further, an external additive is externally added to the surface of the toner particles as required. As a method of adding external additives, a predetermined amount of classified toner and various known external additives are compounded, and a double con mixer, a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano The method of stirring and mixing using mixing apparatuses, such as a hybrid (made by Nippon Coke Kogyo Co., Ltd.) and Nobilta (made by Hosokawa Micron Ltd.), as an external additive machine is mentioned.
In addition, an external additive may be externally added before surface treatment by heat treatment. In this case, since the external additive adheres to the surface of the toner particles by heat treatment, the surface of the toner particles is less likely to be scraped even by stress due to long-time printing. Therefore, it is preferable because the density fluctuation after printing for a long time is small even in a normal temperature low humidity environment or a high temperature high humidity environment, and fogging is improved.

<Analytical method>
(Evaluation of crystalline polyester dispersion state of toner cross section by TEM)
The cross-sectional observation of the toner by a transmission electron microscope (TEM) and the evaluation of the crystalline polyester domain can be carried out as follows.
By ruthenium staining the toner cross section, a crystalline polyester resin can be obtained as a clear contrast. The crystalline polyester resin is dyed weaker than the organic components constituting the inside of the toner. This is considered to be because the infiltration of the dye material into the crystalline polyester resin is weaker than the organic component inside the toner due to the difference in density and the like.
Since the amount of ruthenium atoms differs depending on the strength of the staining, the strongly stained portion is rich in these atoms and does not transmit the electron beam, and becomes dark on the observation image and the weakly stained portion The electron beam is easily transmitted and becomes white on the observation image.
An Os film (5 nm) and a naphthalene film (20 nm) are applied to the toner as a protective film using an osmium plasma coater (filgen, OPC80T), embedded with a photocurable resin D800 (Nippon Denshi Co., Ltd.), and then A toner cross section with a film thickness of 60 nm (or 70 nm) was produced at a cutting speed of 1 mm / s using a sonic ultramicrotome (Leica, UC7).
The obtained cross section was stained for 15 minutes in an atmosphere of RuO 4 gas of 500 Pa using a vacuum electron staining apparatus (filgen, VSC4R1H), and STEM observation was performed using a TEM (JEOL, JEM2800).
The probe size of STEM was 1 nm, and the image size was acquired at 1024 × 1024 pixels.
The obtained image is binarized (step 120/255 steps) using image processing software "Image-Pro Plus (manufactured by Media Cybernetics)".
The obtained cross-sectional image before binarization is shown in FIG. As seen in FIG. 1, the crystalline domains of the crystalline polyester can be confirmed in a black needle shape, and the obtained image is binarized to extract the crystalline domains and measure the size thereof. In the present invention, when cross-sectional observation is performed on 20 randomly selected toners, the lengths of the major axis and the minor axis of the crystal domain of crystalline polyester whose length can be measured are counted 100%. At that time, the number average of the major axis lengths of crystalline polyester crystals (number average diameter (Dc)) in the region (the range of the arrow d sandwiched by dotted lines in FIG. 1) from the toner surface to 0.30 μm inside Ask for In addition, it shall not measure about the crystal | crystallization which exists on the boundary of 0.30 micrometer from the surface of a toner (it exists on a boundary).
Here, the major axis length of the crystalline domain of the crystalline polyester is the longest distance (a in FIG. 2) in the crystalline domain of the cross-sectional image, as shown in FIG. It is the shortest distance at the point position (b in FIG. 2).
The needle shape in the present invention is an elongated shape having a high degree of straightness, a minor axis length of 25 nm or less, and an aspect ratio (major axis length / minor axis length) of 3 or more and a crystal. When center points in the minor axis direction at both ends in the major axis direction are connected by a straight line, it is defined that the deviation of the crystal outline from the straight line is within 100% of the minor axis length of the crystal. .
(Frequency distribution of major axis length of the crystalline polyester resin and its maximum value)
The major axis length of the crystalline polyester in the region from the toner surface to the inner side of 0.30 μm measured in this way is classified into intervals of 5 nm intervals such as more than 0 nm and 5 nm or less and 5 nm and 10 nm or less. Create The maximum value of the major axis length of the section where the frequency is maximum is taken as a representative value.

(Number average diameter of primary particles of inorganic fine powder)
The measurement of the number average diameter of the primary particles of the strontium titanate fine powder in the present invention is performed using a Hitachi ultra-high resolution field emission scanning electron microscope (FE-SEM) S-4800 (Hitachi High-Technologies Corp.) .
The measurement is performed on toner particles after the inorganic fine powder is mixed.
The magnification of the image was 50,000, and the photographed photograph was further doubled, and from the obtained FE-SEM photographic image, the maximum diameter (long axis diameter) a and the minimum diameter (short axis diameter) of the inorganic fine powder B) Measure b) and let (a + b) / 2 be the particle size of the particles. The particle diameters of 100 randomly selected inorganic fine powders are measured to obtain an arithmetic mean, and the number average diameter of primary particles of the inorganic fine powders is obtained.

(Measurement of endothermic peak of crystalline polyester and wax)
The peak temperature (Tp) of the maximum endothermic peak of the crystalline polyester crystals and wax in the toner can be measured by the heat absorption amount ΔH measured by differential thermal analysis (DSC). By separating the crystalline resin from the toner using preparative GPC, the peak of the crystalline resin can be identified.
The peak temperature (Tp) of the maximum endothermic peak of the toner etc. (toner, crystalline polyester) in the present invention is measured under the following conditions using DSC Q1000 (manufactured by TA Instruments).
Heating 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 heat of fusion 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. Use a silver empty pan as a reference.

(Softening point of resin)
The softening point of the resin is measured according to a manual attached to the apparatus using a constant load extrusion capillary type rheometer "flow characteristic evaluation apparatus Flow Tester CFT-500D" (manufactured by Shimadzu Corporation). In this apparatus, while applying a constant load from the top of the measurement sample with a piston, the temperature of the measurement sample filled in the cylinder is raised and melted, and the melted measurement sample is extruded from the die at the bottom of the cylinder. It is possible to obtain a flow curve showing the relationship between temperature and temperature.
In the present invention, the "melting temperature in the 1/2 method" described in the manual attached to the "Flow Characteristic Evaluation Device Flow Tester CFT-500D" is taken as the softening point. The melting temperature in the 1⁄2 method is calculated as follows. First, a half of the difference between the amount of drop Smax of the piston at the end of the outflow and the amount Smin of drop of the piston at the start of the outflow is determined (this is taken as X. X = (Smax-Smin) / 2). The temperature of the flow curve when the amount of descent of the piston in the flow curve is X is the melting temperature in the 1/2 method.
About 1.0 g of the resin is compression molded at about 10 MPa for about 60 seconds under an environment of 25 ° C. using a tablet molding compressor (for example, NT-100H, manufactured by NPA Systems Inc.), The cylindrical one having a diameter of about 8 mm is used.
The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising method start temperature: 50 ° C
Reaching temperature: 200 ° C
Measurement interval: 1.0 ° C
Heating rate: 4.0 ° C / min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0 mm

(Weight average particle diameter of toner particles (D4))
The weight average particle diameter (D4) of the toner particles is measured with a Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.), a precise particle size distribution measuring device by a pore electrical resistance method equipped with an aperture tube of 100 μm. Measurement data is measured using 25,000 channels of 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, a solution in which special grade sodium chloride is dissolved in ion exchange water so that the concentration is about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
In addition, before performing measurement and analysis, the setting of the dedicated software is performed as follows.
Set the total count number in the control mode to 50000 particles, change the number of measurements to 1 on the "Change standard measurement method (SOM) screen" of the dedicated software, and set the Kd value to "standard particle 10.0 μm" (Beckman Coulter Set the value obtained using By pressing the threshold / noise level measurement button, the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the flush of the aperture tube after measurement.
In the dedicated software “pulse to particle size conversion setting screen”, 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) Place about 200 ml of the electrolytic aqueous solution in a 250 ml round bottom beaker made exclusively for Multisizer 3 and set it on a sample stand, and stir the stirrer rod counterclockwise at 24 revolutions / second. Then, dirt and air bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.
(2) About 30 ml of the above-mentioned electrolytic aqueous solution is placed in a 100 ml flat bottom beaker made of glass, and "contaminone N" (a nonionic surfactant, an anionic surfactant, an organic builder precisely measured in pH 7 as a dispersant) Add about 0.3 ml of a diluted solution obtained by diluting a 10% by weight aqueous solution of a neutral detergent for cell washing (manufactured by Wako Pure Chemical Industries, Ltd.) with ion-exchanged water three times by mass.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated 180 degrees out of phase, and an electric output of 120 W is provided in a water tank of "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) A predetermined amount of ion exchange water is placed, and about 2 ml of the Contaminone N is added to the water tank.
(4) The beaker of said (2) is set to the beaker fixing hole of the said ultrasonic dispersion device, and an ultrasonic dispersion device is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized.
(5) While the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolytic aqueous solution and dispersed. Then, ultrasonic dispersion processing is continued for another 60 seconds. In ultrasonic dispersion, the water temperature of the water tank is appropriately adjusted so as to be 10 ° C. or more and 40 ° C. or less.
(6) In the round bottom beaker of the above (1) placed in the sample stand, the electrolyte aqueous solution of the above (5) in which the toner is dispersed using a pipette is dropped to adjust the measurement concentration to about 5%. . Then, measurement is performed until the number of measurement particles reaches 50,000.
(7) The measurement data is analyzed by the dedicated software attached to the device to calculate the weight average particle diameter (D4). The “average diameter” on the analysis / volume statistical value (arithmetic mean) screen when the graph / volume% is set by dedicated software is the weight average particle diameter (D4).

<Production Example of Strontium Titanate Fine Powder 1>
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate was washed with an aqueous alkali solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and the washing was repeated until the conductivity of the supernatant became 70 μS / cm.
A 0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was put into a reaction container made of SUS and purged with nitrogen gas. Furthermore, 0.5 mol / in SrTiO ₃ conversion
Distilled water was added to reach L. The slurry was heated up to 80 ° C. at 7 ° C./hour in a nitrogen atmosphere and reacted for 6 hours after reaching 80 ° C. After the reaction, the reaction solution was cooled to room temperature, the supernatant was removed, and the washing was repeated with pure water. Thereafter, the above slurry is further put into an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry under a nitrogen atmosphere, and while stirring, a calcium sulfate aqueous solution is added dropwise to stir the perovskite crystal surface. Calcium phosphate was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 1 in which the surface not subjected to the sintering step was treated with calcium stearate. . The filtration was carried out with a Nutche. The obtained cake was dried to obtain a fine powder of strontium titanate 1 which did not go through the sintering step. As a result of observing the shape of this strontium titanate fine powder 1 by SEM, it had a rectangular and / or cubic particle shape. Physical properties of the strontium titanate fine powder 1 are shown in Table 1.

(Production Example of Strontium Titanate Fine Powder 2)
The hydrous titanium oxide obtained by hydrolysis by adding ammonia water to titanium tetrachloride aqueous solution is washed with pure water, and the slurry of hydrous titanium oxide is 0.3% sulfuric acid as SO ₃ to hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 0.6 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and the washing was repeated until the conductivity of the supernatant became 50 μS / cm.
A 0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was put into a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ . The slurry was heated to 60 ° C. at 10 ° C./hour in a nitrogen atmosphere, and reacted for 7 hours after reaching 60 ° C. After the reaction, the reaction solution was cooled to room temperature, the supernatant was removed, and the washing was repeated with pure water. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 2 in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of the strontium titanate fine powder 2 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 3)
The hydrous titanium oxide obtained by hydrolysis by adding ammonia water to an aqueous solution of titanium tetrachloride is washed with pure water, and a slurry of the hydrous titanium oxide is treated with 0.25% sulfuric acid as SO _{3 with} respect to hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.7, and washing was repeated until the conductivity of the supernatant reached 50 μS / cm.
A 0.95-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was put into a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ .
The slurry was heated to 65 ° C. at 10 ° C./hour in a nitrogen atmosphere and reacted for 8 hours after reaching 65 ° C. After the reaction, the reaction solution was cooled to room temperature, and after removing the supernatant, washing with pure water was repeated. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 3 in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of this strontium titanate fine powder 3 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 4)
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate was washed with an aqueous alkali solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 0.8 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and the washing was repeated until the conductivity of the supernatant became 70 μS / cm.
To the hydrous titanium oxide, 0.96 times molar amount of Sr (OH) ₂ .8H ₂ O was added, placed in a reaction container made of SUS, and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.7 mol / liter in terms of SrTiO ₃ . The slurry was heated to 65 ° C. at 8 ° C./hour in a nitrogen atmosphere, and reacted for 4 hours after reaching 65 ° C. After the reaction, the reaction solution was cooled to room temperature, and after removing the supernatant, washing was repeated. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain fine powder 4 of strontium titanate in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of this strontium titanate fine powder 4 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 5)
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate was washed with an aqueous alkali solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 0.8 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and the washing was repeated until the conductivity of the supernatant became 70 μS / cm.
A 0.95-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was put into a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.7 mol / liter in terms of SrTiO ₃ . The slurry was heated to 65 ° C. at 8 ° C./hour in a nitrogen atmosphere, and reacted for 4 hours after reaching 65 ° C. After the reaction, the reaction solution was cooled to room temperature, and after removing the supernatant, washing was repeated. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain fine powder 5 of strontium titanate in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of this strontium titanate fine powder 5 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 6)
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate was washed with an aqueous alkali solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 1.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and the washing was repeated until the conductivity of the supernatant became 100 μS / cm.
A 1.02 times molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was put in a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.3 mol / liter in terms of SrTiO ₃ . The slurry was heated to 90 ° C. at 70 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 90 ° C. After the reaction, the reaction solution was cooled to room temperature, the supernatant was removed, and the washing was repeated with pure water. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 6 in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of this strontium titanate fine powder 6 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 7)
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate was washed with an aqueous alkali solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust its pH to 4.3 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 8.0, and washing was repeated until the conductivity of the supernatant reached 100 μS / cm.
A 1.10-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.3 mol / liter in terms of SrTiO ₃ .
The slurry was heated to 95 ° C. at 25 ° C./hour in a nitrogen atmosphere, and reacted for 5 hours after reaching 95 ° C. After the reaction, the reaction solution was cooled to room temperature, and after removing the supernatant, washing with pure water was repeated. Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 7 in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of the strontium titanate fine powder 7 by SEM, it had a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Fine Powder 8)
A hydrous titanium oxide obtained by hydrolysis by adding ammonia water to an aqueous solution of titanium tetrachloride was washed with pure water until the electric conductivity of the supernatant liquid became 90 μS / cm.
A 1.5-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a reaction container made of SUS and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.2 mol / liter in terms of SrTiO ₃ .
The slurry was heated to 80 ° C. at 10 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, the reaction solution was cooled to room temperature, and after removing the supernatant, washing with pure water was repeated.
Furthermore, under nitrogen atmosphere, the above slurry is put in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, calcium sulfate aqueous solution is dropped to obtain calcium stearate on the surface of perovskite crystals. It was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with a Nutche, and the obtained cake was dried to obtain a fine powder of strontium titanate 8 in which the surface not subjected to the sintering step was treated with calcium stearate. . As a result of observing the shape of the strontium titanate fine powder 8 by SEM, it has a rectangular and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Sintered Fine Powder (Strontium Titanate Fine Powder 9))
After 600 g of strontium carbonate and 350 g of titanium oxide were wet mixed in a ball mill for 8 hours, it was filtered and dried, this mixture was molded at a pressure of 10 kg / cm ² and sintered at 1200 ° C. for 7 hours. This was mechanically pulverized to obtain strontium titanate fine powder 9 having an average particle diameter of 50 nm of primary particles after the sintering step. As a result of observing the shape of this strontium titanate fine powder 9 by SEM, it has an indeterminate shape in which primary particles are aggregated.

(Synthesis Example of Amorphous Polyester A1)
Polyoxypropylene (2.2) -2, 2-bis (4-hydroxyphenyl) propane: 73.3 parts by mass (0.20 mol; 100.0 mol% relative to the total number of moles of polyhydric alcohol)
Terephthalic acid: 22.4 parts by mass (0.13 mol; 82.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
-Adipic acid: 4.3 parts by mass (0.03 mol; 18.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
-Titanium tetrabutoxide (esterification catalyst): 0.5 parts by mass The above materials were weighed in a reaction vessel equipped with a cooling pipe, a stirrer, a nitrogen introducing pipe, and a thermocouple. Next, the inside of the flask was replaced with nitrogen gas, and the temperature was gradually raised while stirring, and reaction was carried out for 4 hours while stirring at a temperature of 200 ° C. to obtain an amorphous polyester resin A1. The softening point of the obtained amorphous polyester resin A1 was 90.degree.

(Synthesis Example of Amorphous Polyesters A2 to A17)
In the synthesis example of the non-crystalline polyester A1, the reaction is carried out in the same manner except that the molar ratio of the alcohol component or the carboxylic acid component to be used and the catalyst are changed as shown in Table 1 to obtain non-crystalline polyester resins A2 to A17. The At that time, the mass parts of the raw materials were adjusted so that the total number of moles of polyhydric alcohol was the same as in Synthesis Example A1.

(Synthesis Example of Amorphous Polyester B1)
· Polyoxypropylene (2.2) -2, 2-bis (4-hydroxyphenyl) propane: 72.4 parts by mass (0.20 mol; 100.0 mol% relative to the total number of moles of polyhydric alcohol)
Terephthalic acid: 22.4 parts by mass (0.13 mol; 80.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
-Adipic acid: 3.4 parts by mass (0.02 mol; 14.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
-Titanium tetrabutoxide (esterification catalyst): 0.5 parts by mass The above materials were weighed in a reaction vessel equipped with a cooling pipe, a stirrer, a nitrogen introducing pipe, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and reaction was performed for 2 hours while stirring at a temperature of 200 ° C.
Furthermore, the pressure in the reaction vessel was lowered to 8.3 kPa and maintained for 1 hour, then cooled to 180 ° C. and returned to atmospheric pressure (first reaction step).
· Trimellitic anhydride: 2.1 parts by mass (0.01 mol; 6.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
-Tert-butyl catechol (polymerization inhibitor): 0.1 parts by mass Then, the above material is added, the pressure in the reaction tank is lowered to 8.3 kPa, and reaction is carried out for 15 hours while maintaining the temperature at 160 ° C, ASTM D36 After confirming that the softening point measured according to -86 reached a temperature of 140 ° C, the temperature was lowered to stop the reaction (second reaction step) to obtain a binder resin B1. The softening point of the obtained binder resin B1 was 140.degree.

(Synthesis Example of Amorphous Polyester B2 to B17)
In the synthesis example of amorphous polyester B1, the reaction is carried out in the same manner except that the molar ratio with the alcohol component or carboxylic acid component used in the first reaction step and the catalyst are changed as shown in Table 3, and amorphous polyester resin Obtained B2 to B17. At that time, the mass parts of the raw materials were adjusted so that the total number of moles of polyhydric alcohol was the same as in Synthesis Example A1.

(Synthesis Example of Crystalline Polyester C1)
-Hexanediol: 34.5 parts by mass (0.29 mol; 100.0 mol% relative to the total number of moles of polyhydric alcohol)
· Dodecanedioic acid: 65.5 parts by mass (0.28 mol; 100.0 mol% relative to the total number of moles of polyvalent carboxylic acid)
The above materials were weighed into a reaction vessel equipped with a condenser, a stirrer, a nitrogen introduction pipe, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and reaction was performed for 3 hours while stirring at a temperature of 140 ° C.
-Tin 2-ethylhexanoate: 0.5 parts by mass Then, the above material is added, the pressure in the reaction vessel is lowered to 8.3 kPa, and the reaction is carried out for 4 hours while maintaining the temperature at 200 ° C. The pressure was gradually released to atmospheric pressure to obtain crystalline polyester resin C1. The obtained crystalline polyester resin 1 showed a melting peak derived from crystallinity.

(Synthesis Example of Crystalline Polyester C2 to C7)
Crystalline polyesters C2 to C7 were obtained in the same manner as in the synthesis example of the crystalline polyester C1, except that the alcohol component and the carboxylic acid component were changed to those described in Table 4. The obtained crystalline polyester resins C2 to C7 showed a melting peak derived from crystallinity.

<Production Example of Toner 1>
Amorphous polyester resin A1 70 parts by mass Amorphous polyester resin B1 30 parts by mass Crystalline polyester resin C1 7.5 parts by mass Hydrocarbon wax (peak temperature of maximum endothermic peak 78 ° C.) 4 parts by mass C . I. Pigment Blue 15: 35 parts by mass, 3,5-di-t-butylsalicylic acid aluminum compound 0.5 parts by mass The above materials are rotated using a Henschel mixer (type FM-75, manufactured by Nippon Coke Kogyo Co., Ltd.) The mixture was mixed at 20 s -1 and a rotation time of 5 minutes, and was then kneaded at a discharge temperature of 135 ° C. by a twin-screw kneader (PCM-30, manufactured by Ikegai Co., Ltd.) set to a temperature of 120 ° C. The obtained kneaded product was cooled at a cooling rate of 15 ° C./min, and roughly crushed to 1 mm or less with a hammer mill to obtain a roughly crushed product. The obtained granulated material was finely pulverized by a mechanical pulverizer (T-250, manufactured by Freund Turbo Co., Ltd.). Furthermore, classification was performed using Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain toner particles. The operating conditions were such that the classification rotor rotational speed was 130 s ⁻¹ and the dispersion rotor rotational speed was 120 s ⁻¹ .
Hydrophobic silica fine powder 0.8 having a BET specific surface area of 100 m ² / g surface-treated with 100 parts by mass of the obtained toner particles with strontium titanate fine powder 1 (0.5 parts by mass) and 10% by mass of polydimethylsiloxane Toner 1 was obtained by adding parts by mass and mixing with a Henschel mixer (type FM-75, manufactured by Nippon Coke Industry Co., Ltd.) at a rotation speed of 30 s ⁻¹ for 10 minutes. The weight average particle size (D4) of Toner 1 was 6.1 μm. In DSC measurement of Toner 1, an endothermic peak derived from crystalline polyester was observed.

<Production Example of Toner 2 to 37>
In the production example of Toner 1, the amorphous polyester used as the raw material, the crystalline polyester, the discharge temperature of kneading, the cooling rate of the obtained kneaded material, and the strontium titanate fine powder are changed as described in Table 5. Toners 2 to 37 were obtained in the same manner as described above.

得られたトナー１〜３７の物性を表６に示す。

Physical properties of the obtained toners 1 to 37 are shown in Table 6.

<Production Example of Magnetic Core Particle 1>
Step 1 (Weighing and mixing step):
62.7 parts by mass of Fe ₂ O ₃ 29.5 parts by mass of MnCO ₃ 6.8 parts by mass of Mg (OH) ₂ 1.0 parts by mass of SrCO _{3 The} ferrite raw materials were weighed so as to achieve the above composition ratio. Thereafter, it was ground and mixed for 5 hours with a dry vibration mill using stainless steel beads of 1/8 inch diameter.
Step 2 (pre-baking step):
The obtained pulverized material was formed into pellets of about 1 mm square by a roller compactor. After removing coarse powder with a vibrating sieve with 3 mm openings and then removing fine powder with a vibrating sieve with 0.5 mm openings, using a burner type baking furnace, under a nitrogen atmosphere (oxygen concentration of 0. The resultant was fired at a temperature of 1000 ° C. for 4 hours at 01% by volume to prepare a calcined ferrite. The composition of the obtained calcined ferrite is as follows.
(MnO) a (MgO) b (SrO) c (Fe2O3) d
In the above equation, a = 0.257, b = 0.117, c = 0.007, d = 0.393
Step 3 (pulverization step):
After crushing to about 0.3 mm with a crusher, 30 parts by mass of water was added to 100 parts by mass of calcined ferrite using zirconia beads of 1/8 inch diameter, and the mixture was crushed for 1 hour by a wet ball mill. The slurry was pulverized for 4 hours by a wet ball mill using alumina beads of 1/16 inch in diameter to obtain a ferrite slurry (finely pulverized product of calcined ferrite).
Step 4 (granulation step):
Add 1.0 part by mass of ammonium polycarboxylate as a dispersant and 2.0 parts by mass of polyvinyl alcohol as a binder to the ferrite slurry with 100 parts by mass of calcined ferrite, and use a spray dryer (manufacturer: Ogawara Kakohki) Granulated into spherical particles. The particles obtained were adjusted in particle size, and then heated at 650 ° C. for 2 hours using a rotary kiln to remove the organic components of the dispersant and the binder.
Step 5 (Firing Step):
In order to control the firing atmosphere, the temperature was raised from room temperature to a temperature of 1300 ° C. for 2 hours in a nitrogen atmosphere (oxygen concentration of 1.00 vol%) in an electric furnace, and then firing was carried out at a temperature of 1150 ° C. for 4 hours. Thereafter, the temperature was lowered to 60 ° C. over 4 hours, the nitrogen atmosphere was returned to the atmosphere, and the temperature was removed at a temperature of 40 ° C. or less.
Step 6 (sorting step):
After crushing the agglomerated particles, the low magnetic force product is cut by magnetic separation, and sieved with a 250 μm mesh sieve to remove coarse particles, and 50% particle diameter (D50) of 37.0 μm on a volume distribution basis. Magnetic core particles 1 were obtained.

<Preparation of Coating Resin 1>
Cyclohexyl methacrylate monomer 26.8 mass%
Methyl methacrylate monomer 0.2 mass%
Methyl methacrylate macromonomer 8.4 mass%
(A macromonomer with a weight average molecular weight of 5,000 having a methacryloyl group at one end)
Toluene 31.3 mass%
Methyl ethyl ketone 31.3 mass%
Azobisisobutyronitrile 2.0 mass%
Among the above materials, cyclohexyl methacrylate, methyl methacrylate, methyl methacrylate macromonomer, toluene and methyl ethyl ketone are added to a four-neck separable flask equipped with a reflux condenser, a thermometer, a nitrogen inlet tube and a stirrer, and nitrogen gas Was introduced and the atmosphere was sufficiently nitrogen atmosphere, and then heated to 80.degree. C., azobisisobutyronitrile was added, and polymerization was performed under reflux for 5 hours. Hexane was injected into the obtained reaction product to precipitate a copolymer, and the precipitate was separated by filtration and then vacuum dried to obtain a coated resin 1. The obtained coating resin 1 was dissolved in 30 parts by mass, 40 parts by mass of toluene, and 30 parts by mass of methyl ethyl ketone to obtain a polymer solution 1 (solid content: 30% by mass).

<Preparation of Coating Resin Solution 1>
Polymer solution 1 (resin solid concentration 30%) 33.3 mass%
66.4 mass% of toluene
Carbon black (Regal 330; made by Cabot) 0.3% by mass
(Primary particle size 25 nm, nitrogen adsorption specific surface area 94 m ² / g, DBP oil absorption 75 ml / 100 g)
The dispersion was dispersed for 1 hour with a paint shaker using zirconia beads of 0.5 mm in diameter. The obtained dispersion was filtered with a 5.0 μm membrane filter to obtain a coating resin solution 1.

<Production Example of Magnetic Carrier 1>
(Resin coating process):
In a vacuum degassing type kneader maintained at normal temperature, the coating resin solution 1 was charged to 100 parts by mass of the filled core particles 1 as 2.5 parts by mass as a resin component. After the addition, the solution was stirred at a rotational speed of 30 rpm for 15 minutes, and after the solvent volatilized at a constant level (80% by mass), the temperature was raised to 80 ° C. while mixing under reduced pressure, toluene was distilled off over 2 hours, and then cooled. The obtained magnetic carrier is separated from low magnetic force components by magnetic separation, passed through a sieve with an opening of 70 μm, and then classified with an air classifier, and 50% particle size (D50) 38.2 μm magnetic carrier based on volume distribution I got one.

<Production Example of Two-Component Developer 1>
8.0 parts by mass of the toner 1 was added to 92.0 parts by mass of the magnetic carrier 1, and mixed by a V-type mixer (V-20, manufactured by Seishin Enterprise Co., Ltd.) to obtain a two-component developer 1.

<Production Example of Two-Component Developer 2-37>
Production was carried out in the same manner as in the production example of the two-component developer 1 except that the toner was changed as shown in Table 7, to obtain two-component developers 2 to 37.

<Evaluation of chargeability>
The above two-component developer was placed in a cyan developing device of the image forming apparatus using a Canon full-color copier imagePress C800 as an image forming apparatus, and the evaluation described below was performed. The modification point is that the mechanism for discharging the excess magnetic carrier from the developing device inside the developing device is removed.
The amount of toner on the paper in the FFh image (solid image) was adjusted to 0.45 mg / cm ² . FFh is a value representing 256 gradations in hexadecimal, 00h being the first gradation (white area) of 256 gradations, and FF being the 256 gradation (solid part) of 256 gradations .
In the endurance image output test, the endurance image output test of 10,000 sheets was conducted at an image ratio of 25% under a high temperature and high humidity environment (H / H; temperature 30 ° C., relative humidity 80%). During 10,000 sheets of continuous sheet passing, sheet passing is performed under the same developing conditions as the first sheet and transfer conditions (without calibration). As the evaluation paper, copy plain paper GF-C081 (A4, basis weight 81.4 g / m ² , sold by Canon Marketing Japan Co., Ltd.) was used for 50,000 sheets of durable image output.
The items and evaluation criteria of the image formation evaluation at the initial stage (first sheet) and at the time of 10,000 sheets continuous sheet feeding are shown below. The evaluation results are shown in Table 8.

(1) Measurement of image density Using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), the initial (first sheet) and the 10,000th FFh image area: image density of solid area Were measured and ranked from the difference Δ between both image densities according to the following criteria. The evaluation results are shown in Table 8.
A: less than 0.05 (very good)
B: 0.05 or more and less than 0.10 (good)
C: 0.10 or more and less than 0.20 (the level at which the effects of the present invention are obtained)
D: 0.20 or more (the level at which the effects of the present invention are not sufficiently obtained).

(2) Measurement of fog In an environment of high temperature and high humidity (H / H; temperature 30 ° C., relative humidity 80%), reflectometer average reflectance Dr (%) of evaluation paper before drawing out It was measured by "REFLECTOMETER MODEL TC-6DS" manufactured by a company. In addition, the reflectance (Ds) (%) of the initial (first) and the 10,000th, 00h image area: white area was measured. From the obtained Dr and Ds (initial (first sheet) and 10,000th sheet), fog (%) was calculated using the following equation. From the obtained fog values, the images were ranked according to the following evaluation criteria. The evaluation results are shown in Table 8.
Fog (%) = Dr (%)-Ds (%).
(Evaluation criteria)
A: Less than 0.5% (very good)
B: 0.5% or more and less than 1.0% (good)
C: 1.0% or more and less than 2.0% (the level at which the effects of the present invention are obtained)
D: 2.0% or more (the level at which the effects of the present invention are not sufficiently obtained).

(3) Change in concentration after standing in a high temperature and high humidity environment The evaluation machine for which the evaluations of (1) and (2) above are finished is as it is under high temperature and high humidity environment (H / H; temperature 30 ° C., relative humidity 80%) I left for a week. After printing on one sheet, FFH image area: The image density of the solid area is measured in the same manner as (1), FFH image area before leaving in a high temperature and high humidity environment: compared with the image density of the solid area The density difference Δ was ranked according to the following criteria. The evaluation results are shown in Table 8.
A: less than 0.05 (very good)
B: 0.05 or more and less than 0.15 (good)
C: 0.15 or more and less than 0.30 (the level at which the effects of the present invention are obtained)
D: 0.30 or more (the level at which the effects of the present invention are not sufficiently obtained).

Claims (5)

Toner particles containing a binder resin, a toner having an inorganic fine powder as an external additive,
The binder resin contains amorphous polyester and crystalline polyester,
The inorganic fine powder contains strontium titanate fine powder,
The number average diameter of primary particles of the strontium titanate fine powder is 30 nm or more and 300 nm or less,
The strontium titanate fine powder is a particle having a cubic and / or rectangular solid particle shape, and having a perovskite crystal structure,
In a transmission electron microscope (TEM) image obtained by binarizing the cross-sectional images of I Ri obtained that the toner in observation,
The number average particle diameter Dc of the major axis length of the crystalline polyester is 40 nm or more and 300 nm or less, observed in a needle shape defined as follows from the toner surface to a depth of 0.30 μm:
In the frequency distribution of the major axis length of the crystalline polyester observed in the needle shape defined as follows to a depth of 0.30 μm from the toner surface, the maximum value exists at 50 nm or more and 290 nm or less Feature Toner.
(Needle-like)
The short axis length is 25 nm or less, the aspect ratio (long axis length / short axis length) is 3 or more, and when central points in the short axis direction at both ends in the long axis direction of crystals are connected by straight lines It refers to a shape in which the deviation of the crystal outline from the straight line is within a length within 100% of the crystal minor axis length.   The toner according to claim 1, wherein the crystalline polyester is a condensation polymer of an aliphatic diol having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms.   3. The toner according to claim 1, wherein the non-crystalline polyester is a condensation polymer of an alcohol component and a carboxylic acid component containing 80 mol% or more of propylene oxide adduct of bisphenol. The toner according to claim 3, wherein the propylene oxide adduct of bisphenols has an average added mole number of propylene oxide to the bisphenols of 1.6 or more and 3.0 or less.   3. The toner according to claim 1, wherein the non-crystalline polyester is a condensation polymer of an alcohol component and a carboxylic acid component containing an aliphatic dicarboxylic acid having 4 to 18 carbon atoms.

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