JP2017003916A - toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner having durable stability in a high temperature and high humidity environment, maintaining charging property even after left in a high temperature and high humidity environment, and showing little density variation or fogging.SOLUTION: The toner comprises toner particles containing a binder resin, and an inorganic powder. The binder resin comprises an amorphous polyester and a crystalline polyester; the inorganic fine powder comprises a strontium titanate fine powder, in which the strontium titanate fine powder has a number average diameter of 30 nm or more and 300 nm or less in the primary particles. The strontium titanate fine powder comprises particles having a cubic and/or rectangular parallelepiped particle form and a perovskite crystalline structure. On a cross-section of the toner by TEM observation, a number average particle diameter Dc in terms of a major axis length of the crystalline polyester observed in an acicular form in a toner surface layer is in a specific range; and in a frequency distribution of the major axis length of the crystalline polyester in the toner surface layer, a maximum is present in a specific range.SELECTED DRAWING: Figure 1

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, demands for high-speed printing and energy saving have further increased. In order to cope with high-speed printing, a technique for melting the toner more quickly in the fixing process has been studied. Further, as a measure for energy saving, a technique for fixing toner at a lower fixing temperature is being studied in order to reduce power consumption in the fixing process.
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 that lowers the glass transition point and softening point of the toner binder resin and has sharp melt properties. In recent years, many toners containing a crystalline polyester resin have been proposed as resins having further sharp melt properties. It is known that the presence of crystalline polyester in the toner greatly affects the properties of the toner.

Patent Document 1 discloses a toner in which the maximum diameter of the crystalline polyester resin domain in the cross section of the toner having a core particle and a shell layer is 0.5 μm or more and 2 μm or less. According to this, it is said that both low temperature fixability and suppression of filming can be achieved. Patent Document 2 discloses a toner having core particles and an outer shell, in which crystalline polyester is finely dispersed in a string-like state in which the ratio of length La to width Lb is 10 or more. Has been. As a result, both low-temperature fixability and heat-resistant storage stability can be achieved, and low-temperature fixability is achieved by the effect of the crystalline polyester.
On the other hand, it is known that crystalline polyester has a low electrical resistance and tends to have a lower chargeability than a toner containing no crystalline polyester. Various studies have been made to devise external additives used for toners for the improvement. Patent Document 3 uses a secondary particle-shaped non-spherical silica in which primary particles of silica are coalesced to provide excellent storage stability in a high-temperature and high-humidity environment, and fluidity, transferability, and low-temperature fixability. Excellent toners are disclosed.

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

According to the study by the present inventors, the toners of Patent Documents 1 and 2 maintain charging stability in a high temperature and high humidity environment, particularly durability stability in a high temperature and high humidity environment and maintenance of chargeability after being left in a high temperature and high humidity environment. That was not enough.
Further, in the invention of Patent Document 3, when the toner is durable at a high printing ratio in a high-temperature and high-humidity environment, or when left in a high-temperature and high-humidity environment, the chargeability of the toner is reduced, and fogging on the white background portion of the image is thereby prevented. Improvement has been demanded because it has not been sufficiently suppressed.
An object of the present invention is to provide a toner that solves the above problems. Specifically, it is to provide a toner that has durability stability in a high temperature and high humidity environment, maintains chargeability even after being left in a high temperature and high humidity environment, and has less density fluctuation and fog.

The toner of the present invention is a toner having toner particles containing a binder resin and inorganic fine powder,
The binder resin contains an amorphous polyester and a 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 cuboid particle shape and a perovskite crystal structure,
In the cross section of the toner by observation with a transmission electron microscope (TEM),
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,
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, the toner has a maximum value of 50 nm to 290 nm.

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

Example of toner cross section of toner of the present invention by transmission electron microscope 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 inorganic fine powder,
The binder resin contains an amorphous polyester and a 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 cuboid particle shape and a perovskite crystal structure,
In the cross section of the toner by observation with a transmission electron microscope (TEM),
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,
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, the toner has a maximum value of 50 nm to 290 nm.

The inventors of the present invention have externally added a specific fine powder of strontium titanate to a toner particle in which the crystalline state of the crystalline polyester in the toner is controlled within a specific range, and then left the sample in a high temperature and high humidity environment. The inventors have found that the charging property is improved and have reached the present invention.
The inventors consider the mechanism as follows.
A developing bias is applied when the toner is agitated in the developing device. It is considered that the negative charge generated by friction due to stirring moves to a fine powder of strontium titanate on the toner surface through a crystalline polyester having a relatively low resistance based on the potential difference. The relative dielectric constant of strontium titanate is about 300, which is higher than that of silica fine powder, which is a general external additive, and acts like a capacitor, and charges are 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 density fluctuation and fogging on the white background are suppressed.

The toner of the present invention contains strontium titanate fine powder as an inorganic fine powder, and the number average diameter of primary particles of the strontium titanate fine powder is 30 nm to 300 nm. The strontium titanate fine powder has a cubic and / or rectangular parallelepiped particle shape and a perovskite crystal structure.
In order 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 is the inventors that the particle shape of the strontium titanate fine powder is important. It became clear by examination.

As a method for producing fine powder of strontium titanate, there is a method obtained by pulverizing after passing through a sintering step, but the fine powder obtained in this way is in the shape of an indeterminate shape or aggregated primary particles. Strontium titanate fine powder of the present invention, for example, by adding strontium hydroxide to a titania sol dispersion obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution, It can synthesize | combine by heating to reaction temperature.
Since the strontium titanate fine powder produced in this way has a cubic / cuboid shape, charge transfer from crystalline polyester to strontium titanate tends to occur. Although the detailed reason is unknown, it is thought that the strontium titanate fine powder of the present invention is derived from its cubic / cuboid shape and has a uniform crystal structure from the inside to the outermost surface. Therefore, it seems that it has a crystal structure that easily receives negative charges from the crystalline polyester and accumulates charges compared to the fine powder of strontium titanate produced by the sintering method.

  The number average diameter of primary particles of strontium titanate fine powder needs to be 30 nm or more and 300 nm or less. If the number average diameter of the primary particles of the strontium titanate fine powder is within this range, negative charges from the crystalline polyester are easily received and charge accumulation is effectively caused. If it is less than 30 nm, the charge accumulation effect is low, and the chargeability after standing in a high-temperature and high-humidity environment tends to decrease. If it exceeds 300 nm, the adhesion to toner particles is weakened, and the charge accumulation effect is also weakened. Therefore, the durability in a high temperature and high humidity environment tends to decrease. More preferably, it is 60 nm or more and 140 nm or less.

The fine powder of strontium titanate used in the present invention is obtained 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 good crystallinity and particle size can be obtained.
For the purpose of removing ions adsorbed on 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, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide. The reaction temperature is preferably 60 ° C. to 100 ° C., and 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 fine strontium titanate powder thus obtained has a perovskite crystal structure.

The fine powder of strontium titanate used in the present invention has a hydrophobic surface treated with a fatty acid or a metal salt thereof, a silicone oil, a silane coupling agent, a titanium coupling agent, etc. It is preferable in that it is easy to accumulate charges.
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 the toner particles from the viewpoint of achieving both the charge accumulation effect and the suppression of separation from the toner surface. 10.0 parts by mass or less is preferable, and 0.2 parts by mass or more and 3.0 parts by mass or less is more preferable.
For mixing the toner particles and the inorganic fine powder, a known mixer such as a Henschel mixer, Mechano hybrid (manufactured by Nihon Coke), super mixer, Nobilta (manufactured by Hosokawa Micron) can be used. The apparatus is not limited.

The toner of the present invention is characterized by containing crystalline polyester.
In the present invention, the crystalline polyester is a polyester in which an endothermic peak is observed in differential scanning calorimetry (DSC).
The crystalline polyester of the present invention has a long axis length of the crystalline polyester observed in a needle shape from the toner surface to a depth of 0.30 μm (toner surface layer) in the cross section of the toner observed by a transmission electron microscope (TEM). The number average particle diameter Dc is 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 exists in the range of 50 nm to 290 nm.

  In the present invention, a needle shape is a shape that is long and straight, has a uniaxial length of 25 nm or less, an aspect ratio of 3 or more, and a short axis direction at both ends of the long axis direction of the crystal. It means that when the center points are connected by a straight line, the deviation of the crystal contour from the straight line is within 100% of the crystal minor axis length. It is presumed that the movement of electric charges inside the toner occurs smoothly because the crystals are needle-like.

  The inventors of the present invention have controlled 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 (toner surface layer) within a range of 40 nm to 300 nm. As a result, it was found that the leakage of charges from the toner surface was suppressed and the negative charge was efficiently transferred to strontium titanate. When the number average particle diameter is less than 40 nm, the charge transfer to the strontium titanate fine powder is difficult to occur, and the charge accumulation effect is hardly exhibited. When the number average particle diameter exceeds 300 nm, the crystalline polyester is easily exposed on the toner surface, the negative charge leakage from the toner surface is superior to the transfer of the negative charge to the strontium titanate fine powder, and the negative charge accumulation effect Is hard to be born. More preferably, it is 50 nm or more and 200 nm or less.

Since the crystalline polyester having a major axis length of 50 nm or more and 290 nm or less tends to work effectively for the movement of negative charges, the maximum value is observed in the frequency distribution of the major axis length of the crystalline polyester observed in a needle shape on the toner surface layer. Is present in the range of 50 nm or more and 290 nm or less. Preferably they are 50 nm or more and 250 nm or less.
The fine strontium titanate powder of the present invention is added as an external additive to the surface of the toner particles. Therefore, the distribution of the major axis length of the crystalline polyester observed in a needle shape from the toner surface to the depth of 0.30 μm that greatly contributes to the charge transfer to the strontium titanate fine powder is important in the present invention.

As a method for causing 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 in the range of 40 nm to 300 nm, there are the following methods. .
By changing the acid / alcohol monomer used to synthesize amorphous polyester and crystalline polyester, the dispersibility and compatibility of crystalline polyester with amorphous polyester can be changed, so that the major axis length can be changed. .
When the toner is produced by the pulverization method, the major axis length can be changed by changing the discharge temperature and the cooling rate after melt-kneading. When a 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 existing up to a depth of 0.30 μm can also be changed by heat-treating the obtained toner particles.
The maximum value in the frequency distribution of the major axis length of the crystalline polyester on the toner surface layer can be controlled by changing the cooling rate after melt-kneading when the toner is produced by a pulverization method. When the 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 obtained toner particles are heat-treated, the maximum value of the frequency distribution of the major axis length of the crystalline polyester on the toner surface layer can also be controlled by changing the treatment temperature and treatment time.

The toner of the present invention is characterized by containing an amorphous polyester and a crystalline polyester as a binder resin.
(Amorphous polyester)
As the amorphous polyester resin used in the present invention, an ordinary polyester resin 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 Examples thereof include diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, and bisphenol derivatives represented by the following formula (1). . Bisphenols such as hydrogenated bisphenol A and bisphenol derivatives represented by the following formula (1) are preferred.

[Wherein, 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, examples of the alcohol component include polyhydric alcohols such as glycerin, pentaerythritol, sorbit, sorbitan, and oxyalkylene ethers of novolac type phenol resins.

  On the other hand, as the divalent carboxylic acid constituting the amorphous polyester resin, benzene dicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydride thereof; succinic acid, adipic acid, sebacic acid, azelain Examples thereof include alkyldicarboxylic acids such as acids or anhydrides thereof. Further, succinic acid substituted with an alkyl group or alkenyl group having 6 to 18 carbon atoms or an anhydride thereof; unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, itaconic acid or an anhydride thereof, etc. It is done. Also, polymellitic carboxylic 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 polycondensing an alcohol component and a carboxylic acid component containing 80 mol% or more (more preferably 90 mol% or more and 100 mol% or less) of a propylene oxide adduct of bisphenols. Are preferred. Further, it is preferably an amorphous polyester obtained by polycondensation of an alcohol component and a carboxylic acid component containing an aliphatic dicarboxylic acid having 4 to 18 carbon atoms (more preferably 6 to 12 carbon atoms). Moreover, it is preferable that the average addition mole number of this propylene oxide adduct with respect to bisphenol is 1.6 to 3.0 mol, and it is more preferable that it is 1.6 to 2.6 mol.
Increasing the ratio of the propylene oxide adduct is preferable from the viewpoint of increasing 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. Moreover, when the average added mole number of the propylene oxide adduct is within the above range, the dispersibility of the crystalline polyester can be improved, and this 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, this portion has a strong affinity with the crystalline polyester, so that the crystalline polyester in the toner has a strong affinity. Dispersibility is improved. This is preferable because fog is further suppressed. The molar ratio of the aliphatic dicarboxylic acid having 4 to 18 carbon atoms to the carboxylic acid component is more preferably 6 mol% or more and 40 mol% or less.

In addition to the above, examples of the aliphatic dicarboxylic acid having 4 to 18 carbon atoms include alkyl dicarboxylic acids such as tetradecanedioic acid and octadecanedioic acid, anhydrides thereof, and lower alkyl esters. In addition, a compound having a structure in which a part of the main chain is branched by an alkyl group such as a methyl group, an ethyl group, or an octyl group, or an alkylene group. Moreover, alicyclic dicarboxylic acid, such as tetrahydrophthalic acid, is mentioned.
The amorphous polyester resin is a catalyst that is usually used, for example, any metal such as tin, titanium, antimony, manganese, nickel, zinc, lead, iron, magnesium, calcium, germanium; and these metal-containing compounds. Can also be produced.
The amorphous polyester resin preferably has an acid value of 1 mgKOH / g or more and 10 mgKOH / g or less from the viewpoint of charging stability.

In addition, the amorphous polyester of the toner of the present invention contains the low-softening point amorphous polyester A and the high softening point amorphous polyester B, which achieves both low-temperature fixability and hot offset resistance. Is preferable.
The content ratio (A / B) of the amorphous polyester A having a low softening point and the amorphous polyester B having a high softening point is 60/40 to 90/10 on a mass basis. From the viewpoint of sex.
The softening point of the amorphous polyester A having a low softening point is preferably 70 ° C. or higher and 100 ° C. or lower from the viewpoint of compatibility between the storage stability of the toner and the low-temperature fixability.
The softening point of the amorphous polyester B having a high softening point is preferably 110 ° C. or higher and 180 ° C. or lower from the viewpoint of hot offset resistance.
In the toner of the present invention, if the content of the amorphous polyester is 60 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the toner particles, it is easy to achieve both excellent low-temperature fixability and hot offset resistance. More preferred.

<Other binder resins>
As the binder resin used in the toner of the present invention, the following polymers may be used in addition to the above amorphous polyester for the purpose of improving pigment dispersibility and improving charging stability and blocking resistance of the toner. It is also possible to add in an amount that does not inhibit the effect of the present invention.
In the present invention, when the dispersibility of the release agent or pigment is improved, the dispersibility of fine crystals of the crystalline polyester on the surface is improved. Therefore, it is preferable that the toner contains other resin as a dispersant.

  Examples of other resins used for the binder resin of the toner of the present invention include the following resins. Styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, and homopolymers thereof; 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 Styrene copolymers such as copolymers, styrene-vinyl methyl ketone copolymers, styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenol resins, natural modified phenol resins, natural resin modified maleic resins, acrylic resins , Methacrylic 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, from the viewpoint of achieving both low-temperature fixability and storage stability at a higher level, the monomer composition of the crystalline polyester resin includes an aliphatic diol having 6 to 12 carbon atoms and a fat having 6 to 12 carbon atoms. It is preferable to use a group dicarboxylic acid.
The aliphatic diol is not particularly limited, but is preferably a chain (more preferably linear) aliphatic diol, such as 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 And glycol and neopentyl glycol. Among these, in particular, linear aliphatic such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and α, ω-diol are preferably exemplified.
Among the above alcohol components, preferably 50 mass% or more, more preferably 70 mass% or more is an alcohol selected from aliphatic diols having 2 to 22 carbon atoms (preferably 6 to 12 carbon atoms). More preferably, among the alcohol components, 80% by mass or more is an alcohol selected from aliphatic diols having 6 to 12 carbon atoms.

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

On the other hand, the aliphatic dicarboxylic acid is not particularly limited, but is preferably a chain (more preferably linear) aliphatic dicarboxylic acid. Specific examples include oxalic acid, malonic acid,
Succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citracone Examples thereof include acids and itaconic acids, and those obtained by hydrolyzing these acid anhydrides or lower alkyl esters are also included.
In the present invention, among the carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more is selected from aliphatic dicarboxylic acids having 2 to 22 carbon atoms (preferably 6 to 12 carbon atoms). It is an acid. More preferably, 80% by mass or more of the carboxylic acid component 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, divalent carboxylic acids include aromatic carboxylic acids such as isophthalic acid and terephthalic acid; n-dodecyl succinic acid, n-dodecenyl succinic aliphatic carboxylic acid; cyclohexane dicarboxylic acid Examples thereof include alicyclic carboxylic acids such as acids, and these acid anhydrides or lower alkyl esters are also included. Among the other carboxylic acid monomers, trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, Aromatic carboxylic acids such as 2,4-naphthalenetricarboxylic acid and pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2 -Aliphatic carboxylic acids such as methylenecarboxypropane are included, and derivatives such as these acid anhydrides or 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 or more and 30 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin. From the viewpoint of achieving both low-temperature fixability and chargeability, it is more preferably from 1 part by mass to 15 parts by mass.

<Colorant>
Examples of the colorant that can be contained in the toner include the following.
Examples of the black colorant include carbon black; those prepared by using a yellow colorant, a magenta colorant, and a cyan colorant and adjusting the color to black. As the colorant, a pigment may be used alone, but it is more preferable from the viewpoint of the image quality of a full-color image to improve the sharpness by using a dye and a pigment together.
Examples of the magenta toner pigment include the following. C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35.
Examples of the magenta toner dye include the following. C. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121; I. Disper thread 9; I. Solvent violet 8, 13, 14, 21, 27; C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. B. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; I. Basic dyes such as Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

Examples of the cyan toner pigment include the following. C. I. Pigment blue 2, 3, 15: 2, 15: 3, 15: 4, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.
Examples of cyan toner dyes include C.I. I. There is Solvent Blue 70.
Examples of the yellow toner pigment include the following. C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; I. Bat yellow 1, 3, 20
Examples of the dye for yellow toner include C.I. I. There is Solvent Yellow 162.
The amount of the colorant used is preferably 0.1 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 in the toner of the present invention include the following. Low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymer, hydrocarbon wax such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxide of hydrocarbon wax such as oxidized polyethylene wax or block copolymer thereof Products: Waxes mainly composed of fatty acid esters such as carnauba wax; Deoxidized part or all of fatty acid esters such as deoxidized carnauba wax.
Furthermore, the following are mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, ceryl alcohol , Saturated alcohols such as merisyl alcohol; polyhydric alcohols such as sorbitol; fatty acids such as palmitic acid, stearic acid, behenic acid, and montanic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, and carnauvir alcohol , Esters with alcohols such as ceryl alcohol, melyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, 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; m-xylene bis stearic acid amide, N, N' aromatic bisamides such as distearyl isophthalic acid amide; calcium stearate, calcium laurate, zinc stearate , Aliphatic metal salts such as magnesium stearate (generally referred to as metal soap); waxes grafted to 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, a hydrocarbon wax such as paraffin wax and Fischer-Tropsch wax, or a fatty acid ester wax such as carnauba wax is preferable from the viewpoint of improving low-temperature fixability and hot offset resistance. In the present invention, a hydrocarbon wax is more preferable in that the hot offset resistance is further improved.
The wax content 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 may contain a charge control agent as necessary. As the charge control agent contained in the toner, known ones can be used. In particular, a metal compound of an aromatic carboxylic acid that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable.
Negative charge control agents include salicylic acid metal compounds, naphthoic acid metal compounds, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid or carboxylic acid in the side chain, sulfonates or sulfonated compounds in the side chain. Examples thereof include a polymer compound, a polymer compound having a carboxylate or a carboxylic acid ester in the side chain, a boron compound, a urea compound, a silicon compound, and a calixarene. Examples of the positive charge control agent include quaternary ammonium salts, polymer compounds having the quaternary ammonium salt in the side chain, guanidine compounds, and imidazole compounds. The charge control agent may be added internally or externally to the toner particles. The addition amount of the charge control agent is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Inorganic fine powder)
In addition to the above-described strontium titanate, the toner of the present invention may contain other inorganic fine powder as required. The inorganic fine powder may be added internally 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 an external additive for improving fluidity, 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. For stabilization of durability, the specific surface area is 10 m ² / g or more and 50 m or less. An inorganic fine powder of ² / g or less is preferable. In order to achieve both improvement in fluidity and stabilization of durability, an inorganic fine powder having a specific surface area in the above range may be used in combination.
The external additive is preferably used in an amount of 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the toner particles. For mixing the toner particles and the external additive, a known mixer such as a Henschel mixer can be used.

<Developer>
The toner of the present invention can also be used as a one-component developer, but in order to further improve dot reproducibility, it can be mixed with a magnetic carrier and used as a two-component developer. Is preferable in that it is obtained.
Examples of magnetic carriers include iron powder with oxidized surface or non-oxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, and the like Magnetic material dispersed resin carriers (so-called resin carriers) containing magnetic materials such as alloy particles, oxide particles, ferrite, and the like, and magnetic materials and binder resins that hold the magnetic materials in a dispersed state are generally known. Things can be used.
When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio at that time is preferably 2% by mass or more and 15% by mass or less as the toner concentration in the two-component developer. More preferably, when the content is 4% by mass or more and 13% by mass or less, usually good results are obtained.

<Manufacturing method>
As a method for producing toner particles, it can be obtained by a known method. However, it is easy to control the major axis length of the crystalline polyester within the range of the present invention, and the binder resin and necessary. Accordingly, a pulverization method in which other materials such as a colorant and wax are melt-kneaded and the kneaded product is cooled and then pulverized and classified is more preferable.
Hereinafter, an example of a toner manufacturing procedure using the pulverization method will be described.

In the raw material mixing step, as a material constituting the toner particles, for example, a predetermined amount of other components such as a binder resin and, if necessary, a wax, a colorant, and a charge control agent are weighed, mixed, and mixed.
Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, a mechano-hybrid (manufactured by Nippon Coke Industries Co., Ltd.), and the like.
Next, the mixed material is melt-kneaded to disperse wax or the like in the binder resin. The kneading discharge temperature is preferably 100 to 155 ° C. In the melt-kneading step, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used, and a single-screw or twin-screw extruder has become the mainstream because of the advantage of continuous production. ing. For example, KTK type twin screw extruder (Kobe Steel Co., Ltd.), TEM type twin screw extruder (Toshiba Machine Co., Ltd.), PCM kneading machine (Ikegai Iron Works Co., Ltd.), twin screw extruder (K-C K Company) Product), co-kneader (manufactured by Buss), kneedex (manufactured by Nippon Coke Industries Co., Ltd.), and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step in order to control the cooling rate of the melt-kneaded product. The cooling rate is 5 to 40 ° C./min. Is preferred.

Next, the cooled product of the resin composition is pulverized to a desired particle size in the pulverization step. In the pulverization process, for example, after coarse pulverization with a pulverizer such as a crusher, a hammer mill, or a feather mill, for example, a kryptron system (manufactured by Kawasaki Heavy Industries), a super rotor (manufactured by Nissin Engineering Co., Ltd.), a turbo mill, etc. Finely pulverize with a fine pulverizer (Freund Turbo) or air jet type.
After that, if necessary, classification of inertial class elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.), centrifugal classification turboplex (manufactured by Hosokawa Micron), TSP separator (manufactured by Hosokawa Micron), Faculty (manufactured by Hosokawa Micron) Classification using a machine or sieving machine to obtain a classified product (toner particles). Among these, Faculty (manufactured by Hosokawa Micron Corporation) is preferable from the viewpoint of improving the transfer efficiency because it can perform the spheroidizing treatment of toner particles simultaneously with the classification.
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), or Meteole Inbo MR Type (manufactured by Nippon Pneumatic Co., Ltd.) is used. Thus, toner particle surface treatment such as spheroidization 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 transferability improvement and cleaning properties. When the toner is produced by the pulverization method, the toner having the above average circularity can be produced by subjecting the toner particles to a surface treatment such as a spheroidizing treatment or a surface treatment by heat treatment.

Further, an external additive is externally treated on the surface of the toner particles as necessary. As a method of externally adding external additives, a predetermined amount of classified toner and various known external additives are blended, and a double-con mixer, V-type mixer, drum-type mixer, super mixer, Henschel mixer, Nauta mixer, mechano Examples thereof include a method of stirring and mixing using a mixing apparatus such as a hybrid (manufactured by Nippon Coke Industries Co., Ltd.), Nobilta (manufactured by Hosokawa Micron Co., Ltd.) or the like as an external additive.
Further, the external additive can be externally treated before the surface treatment by heat treatment. In this case, since the external additive is fixed to the surface of the toner particles by the heat treatment, the surface of the toner particles is hardly scraped even by stress due to long-time printing. Therefore, it is preferable in a low temperature and low humidity environment and a high temperature and high humidity environment because the density fluctuation after printing for a long time is small and the fog is improved.

<Analysis method>
(Evaluation of dispersion state of crystalline polyester in toner cross section by TEM)
Cross-sectional observation of the toner with a transmission electron microscope (TEM) and evaluation of the crystalline polyester domain can be carried out as follows.
By ruthenium dyeing 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 component constituting the inside of the toner. This is presumably because the infiltration of the dye material into the crystalline polyester resin is weaker than the organic component inside the toner due to a difference in density.
Because the amount of ruthenium atoms varies depending on the intensity of staining, the strongly stained part has many of these atoms, the electron beam does not pass through, it becomes black on the observation image, and the part that is weakly stained is The electron beam is easily transmitted and becomes white on the observation image.
Using an osmium plasma coater (filgen, OPC80T), an Os film (5 nm) and a naphthalene film (20 nm) were applied to the toner as a protective film, and embedded with a photo-curable resin D800 (JEOL). Using a sonic ultramicrotome (Leica, UC7), a toner cross section having a film thickness of 60 nm (or 70 nm) was prepared at a cutting speed of 1 mm / s.
The obtained cross section was dyed for 15 minutes in a RuO4 gas 500 Pa atmosphere using a vacuum electron dyeing apparatus (filgen, VSC4R1H), and STEM observation was performed using TEM (JEOL, JEM2800).
The STEM probe size was 1 nm, and the image size was 1024 × 1024 pixels.
The obtained image is binarized (threshold 120/255 stage) by image processing software “Image-Pro Plus (Media Cybernetics)”.
The obtained cross-sectional image before binarization is shown in FIG. As can be seen in FIG. 1, the crystalline domains of the crystalline polyester can be confirmed as black needles, and the obtained images are binarized to extract the crystalline domains and measure their sizes. In the present invention, when 20 cross sections of 20 randomly selected toners are observed, the lengths of the major axis and the minor axis of the crystalline domain of the crystalline polyester whose length can be measured are measured. At that time, the number average (number average diameter (Dc)) of the major axis length of the crystalline polyester in the region from the toner surface to the inside of 0.30 μm (the range of the arrow d sandwiched between the dotted lines in FIG. 1). Ask for. It should be noted that crystals that cross the 0.30 μm boundary (exist on the boundary) from the toner surface are not measured.
Here, as shown in FIG. 2, the major axis length of the crystalline domain of the crystalline polyester is the longest distance (a in FIG. 2) in the crystal domain of the cross-sectional image, and the minor axis length is the center of the crystal major axis. This is the shortest distance (b in FIG. 2) at the point position.
The needle shape in the present invention is a shape that is long and straight and has a short axis length of 25 nm or less, an aspect ratio (major axis length / short axis length) of 3 or more, and a crystal shape. When the central points in the minor axis direction at both ends of the major axis direction are connected by a straight line, the shape of the crystal contour deviation from the straight line is defined as a shape that is within 100% of the crystal minor axis length. .
(Frequency distribution of the 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 measured in this way to the inside of 0.30 μm is classified into 5 nm intervals such as more than 0 nm and less than 5 nm and more than 5 nm and less than 10 nm. Create The maximum value of the major axis length of the section where the frequency is maximum is taken as the representative value.

(Number average diameter of primary particles of inorganic fine powder)
The number average diameter of primary particles of the strontium titanate fine powder in the present invention is measured using a Hitachi ultra-high resolution field emission scanning electron microscope (FE-SEM) S-4800 (Hitachi High-Technologies Corporation). .
The measurement is performed on the toner particles after mixing the inorganic fine powder.
The photographic magnification is 50,000 times, and the photographed photograph is further doubled. From the obtained FE-SEM photograph image, the maximum diameter (major axis diameter) a and the minimum diameter (minor axis diameter) of the inorganic fine powder are obtained. ) B is measured, and (a + b) / 2 is defined as the particle size of the particles. The particle size is measured for 100 randomly selected inorganic fine powders, the arithmetic average is obtained, and the number average diameter of primary particles of the inorganic fine powder is obtained.

(Measurement of endothermic peak of crystalline polyester and wax)
The peak temperature (Tp) of the crystalline polyester crystal and wax maximum endothermic peak in the toner can be measured by the endothermic amount ΔH measured by differential calorimetry (DSC). By separating the crystalline resin from the toner using preparative GPC, the peak of the crystalline resin can be specified.
The peak temperature (Tp) of the maximum endothermic peak of the toner or the like (toner, crystalline polyester) in the present invention is measured using DSC Q1000 (manufactured by TA Instruments) under the following conditions.
Temperature increase rate: 10 ° C / min
Measurement start temperature: 20 ° C
Measurement end temperature: 180 ° C
The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium.
Specifically, about 5 mg of a sample is precisely weighed, placed in a silver pan, and measured once. A silver empty pan is used as a reference.

(Softening point of resin)
The softening point of the resin is measured by using a constant load extrusion type capillary rheometer “flow characteristic evaluation device Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with the piston, the measurement sample filled in the cylinder is heated and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder, and the piston drop amount at this time A flow curve showing the relationship between temperature and temperature can be obtained.
In the present invention, the “melting temperature in the 1/2 method” described in the manual attached to the “flow characteristic evaluation apparatus Flow Tester CFT-500D” is the softening point. The melting temperature in the 1/2 method is calculated as follows. First, ½ of the difference between the piston lowering amount Smax at the time when the outflow ends and the piston lowering amount Smin at the time when the outflow starts is obtained (this is X. X = (Smax−Smin) / 2). Then, the temperature of the flow curve when the piston descending amount is X in the flow curve is the melting temperature in the 1/2 method.
As a measurement sample, about 1.0 g of resin is compression-molded at about 10 MPa using a tablet molding compressor (for example, NT-100H, manufactured by NPA System Co., Ltd.) in an environment of 25 ° C. for about 60 seconds. A cylindrical shape having a diameter of about 8 mm is used.
The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising start temperature: 50 ° C
Achieving temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature increase 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: 1.0mm

(Weight average particle diameter of toner particles (D4))
The weight average particle diameter (D4) of the toner particles is measured with a precision particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube. Measured data with 25,000 effective measurement channels using the dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) for condition setting and measurement data analysis Analyze and calculate.
As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
Prior to measurement and analysis, the dedicated software is set as follows.
In the “Standard measurement method (SOM) change screen” of the dedicated software, set the total count in the control mode to 50000 particles, the number of measurements is 1 and the Kd value is “standard particles 10.0 μm” (Beckman Coulter Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.
In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm or more and 60 μm or less.

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

<Production Example of Strontium Titanate Fine Powder 1>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.
A 0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Furthermore, 0.5 mol / in terms of SrTiO ₃
Distilled water was added to L. The slurry was heated to 80 ° C. at a rate of 7 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, the reaction mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water. Thereafter, in a nitrogen atmosphere, the slurry is placed 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, an aqueous calcium sulfate solution is dropped to stir the perovskite crystal surface. Calcium phosphate was precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 1 whose surface not subjected to the sintering step was treated with calcium stearate. . Filtration was performed with Nutsche. The obtained cake was dried to obtain fine strontium titanate powder 1 that 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 parallelepiped and / or cubic particle shape. Table 1 shows the physical properties of the fine strontium titanate powder 1.

(Production Example of Strontium Titanate Fine Powder 2)
The hydrous titanium oxide obtained by hydrolysis by adding aqueous ammonia to the aqueous titanium tetrachloride was washed with pure water, and 0.3% sulfuric acid was added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.6 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant liquid reached 50 μS / cm.
0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel 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 a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 7 hours after reaching 60 ° C. After the reaction, the reaction mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water. Further, in a nitrogen atmosphere, the slurry is placed 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, an aqueous calcium sulfate solution is added dropwise to add calcium stearate to the perovskite crystal surface. Precipitated. Thereafter, the slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate fine powder 2 whose 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 2 by SEM, it had a rectangular parallelepiped and / or cubic particle shape.

(Synthesis example of strontium titanate fine powder 3)
The hydrous titanium oxide obtained by hydrolysis by adding aqueous ammonia to an aqueous titanium tetrachloride solution is washed with pure water, and 0.25% sulfuric acid is added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the 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 electrical 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 placed in a SUS reaction vessel and purged with nitrogen gas. Further, 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 a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 8 hours after reaching 65 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water. Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry. Precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate fine powder 3 whose 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 3 by SEM, it had a rectangular parallelepiped and / or cubic particle shape.

(Synthesis example of fine strontium titanate powder 4)
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.8 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.
0.96 times the molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Further, 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 mixture was cooled to room temperature, the supernatant was removed, and washing was repeated. Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry. Precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 4 whose 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 parallelepiped and / or cubic particle shape.

(Synthesis example of fine strontium titanate powder 5)
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.8 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.
A 0.95-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Further, 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 mixture was cooled to room temperature, the supernatant was removed, and washing was repeated. Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry. Precipitated. Thereafter, the slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 5 whose 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 parallelepiped and / or cubic particle shape.

(Synthesis example of strontium titanate fine powder 6)
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 1.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 100 μS / cm.
To this hydrous titanium oxide, 1.02 times the molar amount of Sr (OH) ₂ .8H ₂ O was added and placed in a SUS reaction vessel, and the nitrogen gas was replaced. 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 mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water. Further, in a nitrogen atmosphere, the slurry is placed 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, an aqueous calcium sulfate solution is added dropwise to add calcium stearate to the perovskite crystal surface. Precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 6 whose 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 6 by SEM, it had a rectangular parallelepiped and / or cubic particle shape.

(Synthesis example of strontium titanate fine powder 7)
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the 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 electrical 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, placed in a SUS reaction vessel, and purged with nitrogen gas. Further, 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 mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water. Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry. Precipitated. Thereafter, the slurry was repeatedly washed with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 7 whose 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 parallelepiped and / or cubic particle shape.

(Synthesis example of fine strontium titanate powder 8)
The hydrous titanium oxide obtained by hydrolysis by adding ammonia water to the aqueous titanium tetrachloride solution was washed with pure water until the electrical conductivity of the supernatant reached 90 μS / cm.
A 1.5-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Further, distilled water was added so as to be 0.2 mol / liter in terms of SrTiO ₃ .
The slurry was heated up to 80 ° C. at 10 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.
Further, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 3% by mass of sodium stearate is dissolved with respect to the solid content of the slurry. Precipitated. Thereafter, the slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain fine strontium titanate powder 8 whose 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 had a rectangular parallelepiped and / or cubic particle shape.

(Synthesis Example of Strontium Titanate Sintered Fine Powder (Strontium Titanate Fine Powder 9))
600 g of strontium carbonate and 350 g of titanium oxide were wet mixed in a ball mill for 8 hours and then filtered and dried. The 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 fine strontium titanate powder 9 having an average primary particle diameter of 50 nm via a sintering process. As a result of observing the shape of this strontium titanate fine powder 9 by SEM, it had an irregular shape in which primary particles were 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% based on the total number of moles of polyhydric alcohol)
-Terephthalic acid: 22.4 parts by mass (0.13 mol; 82.0 mol% based on the total number of polyvalent carboxylic acids)
Adipic acid: 4.3 parts by mass (0.03 mol; 18.0 mol% with respect to the total number of polyvalent carboxylic acids)
Titanium tetrabutoxide (esterification catalyst): 0.5 part by mass The above materials were weighed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introduction tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the mixture was reacted for 4 hours while stirring at a temperature of 200 ° C. to obtain amorphous polyester resin A1. The resulting amorphous polyester resin A1 had a softening point of 90 ° C.

(Synthesis example of amorphous polyesters A2 to A17)
In the synthesis example of the amorphous polyester A1, the reaction is performed in the same manner except that the alcohol component or carboxylic acid component to be used and the molar ratio and the catalyst are changed as shown in Table 1 to obtain amorphous polyester resins A2 to A17. It was. 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% with respect to the total number of polyhydric alcohols)
・ Terephthalic acid: 22.4 parts by mass (0.13 mol; 80.0 mol% based on the total number of polyvalent carboxylic acids)
Adipic acid: 3.4 parts by mass (0.02 mol; 14.0 mol% based on the total number of polyvalent carboxylic acids)
Titanium tetrabutoxide (esterification catalyst): 0.5 part by mass The above materials were weighed in a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introduction tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200 ° C.
Further, the pressure in the reaction vessel was lowered to 8.3 kPa, 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% based on the total number of polycarboxylic acids)
Tert-Butylcatechol (polymerization inhibitor): 0.1 part by mass Thereafter, the above materials are added, the pressure in the reaction vessel is lowered to 8.3 kPa, and the reaction is performed for 15 hours while maintaining the temperature at 160 ° C., and ASTM D36 After confirming that the softening point measured in accordance with −86 reached a temperature of 140 ° C., the reaction was stopped by lowering the temperature (second reaction step) to obtain a binder resin B1. The resulting binder resin B1 had a softening point of 140 ° C.

(Synthesis example of amorphous polyesters B2 to B17)
In the synthesis example of the amorphous polyester B1, the reaction is performed in the same manner except that the alcohol component or carboxylic acid component used in the first reaction step and the molar ratio and the catalyst are changed as shown in Table 3, and the amorphous polyester resin. B2 to B17 were obtained. 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% with respect to the total number of polyhydric alcohols)
-Dodecanedioic acid: 65.5 parts by mass (0.28 mol; 100.0 mol% with respect to the total number of polyvalent carboxylic acids)
The above materials were weighed into a reaction vessel equipped with a cooling tube, a stirrer, a nitrogen introduction tube, and a thermocouple. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 3 hours while stirring at a temperature of 140 ° C.
-Tin 2-ethylhexanoate: 0.5 parts by mass Thereafter, the above materials were added, the pressure in the reaction vessel was lowered to 8.3 kPa, and the reaction was continued for 4 hours while maintaining the temperature at 200 ° C. The pressure was gradually released and returned to normal pressure to obtain a 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 shown in Table 4. The obtained crystalline polyester resins C2 to C7 exhibited melting peaks derived from crystallinity.

<Production Example of Toner 1>
Amorphous polyester resin A1 70 parts by weight Amorphous polyester resin B1 30 parts by weight Crystalline polyester resin C1 7.5 parts by weight Hydrocarbon wax (peak temperature of maximum endothermic peak 78 ° C) 4 parts by weight . I. Pigment Blue 15: 3 5 parts by mass, 3,5-di-t-butylsalicylic acid aluminum compound 0.5 part by mass Using the above materials with a Henschel mixer (FM-75 type, manufactured by Nihon Coke Kogyo Co., Ltd.), the rotational speed After mixing for 20 s-1 and a rotation time of 5 minutes, the mixture was kneaded at a discharge temperature of 135 ° C. with a biaxial kneader (PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a temperature of 120 ° C. The obtained kneaded product was cooled at a cooling rate of 15 ° C./min, and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product. The obtained crushed material was finely pulverized with a mechanical pulverizer (T-250, manufactured by Freund Turbo). Further, classification was performed using Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain toner particles. The operating conditions were a classification rotor rotational speed of 130 s ⁻¹ and a distributed rotor rotational speed of 120 s ⁻¹ .
Hydrophobic silica fine powder with a BET specific surface area of 100 m ² / g 0.8 treated with strontium titanate fine powder 1 (0.5 mass part) and 10% by mass of polydimethylsiloxane was added to 100 parts by mass of the toner particles obtained. Toner 1 was obtained by adding part by mass and mixing with a Henschel mixer (FM-75 type, manufactured by Nippon Coke Kogyo Co., Ltd.) at a rotation speed of 30 s ⁻¹ and a rotation time of 10 minutes. The weight average particle diameter (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 Toners 2 to 37>
In the production example of the toner 1, the amorphous polyester and crystalline polyester used as raw materials, the kneading discharge temperature, the cooling rate of the obtained kneaded product, and the strontium titanate fine powder were 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。

Table 6 shows the physical properties of Toner 1 to 37 obtained.

<Example of production of magnetic core particle 1>
-Process 1 (weighing / mixing process):
Fe ₂ O ₃ 62.7 parts by mass MnCO ₃ 29.5 parts by mass Mg (OH) ₂ 6.8 parts by mass SrCO ₃ 1.0 parts by mass Ferrite raw materials were weighed so that the above composition ratio was the above. Thereafter, the mixture was pulverized and mixed for 5 hours in a dry vibration mill using 1/8 inch diameter stainless steel beads.
-Process 2 (temporary baking process):
The obtained pulverized product was formed into pellets of about 1 mm square using a roller compactor. After removing the coarse powder from the pellets with a vibrating sieve having a mesh opening of 3 mm, and then removing the fine powders with a vibrating sieve having a mesh opening of 0.5 mm, using a burner-type firing furnace, under a nitrogen atmosphere (oxygen concentration of 0.1. And calcined at a temperature of 1000 ° C. for 4 hours to prepare calcined ferrite. The composition of the obtained calcined ferrite is as follows.
(MnO) a (MgO) b (SrO) c (Fe2O3) d
In the above formula, a = 0.257, b = 0.117, c = 0.007, d = 0.393
-Step 3 (grinding step):
After pulverizing 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 having a diameter of 1/8 inch, and pulverized with a wet ball mill for 1 hour. The slurry was pulverized for 4 hours by a wet ball mill using alumina beads having a diameter of 1/16 inch to obtain a ferrite slurry (a finely pulverized product of calcined ferrite).
-Process 4 (granulation process):
To the ferrite slurry, 1.0 part by mass of ammonium polycarboxylate as a dispersant and 100 parts by mass of polyvinyl alcohol as a binder are added to 100 parts by mass of the calcined ferrite, and a spray dryer (manufacturer: Okawara Kako) is used. Granulated into spherical particles. After adjusting the particle size of the obtained particles, using a rotary kiln, it was heated at 650 ° C. for 2 hours to remove the organic components of the dispersant and the binder.
-Process 5 (firing process):
In order to control the firing atmosphere, the temperature was raised from room temperature to 1300 ° C. in a nitrogen atmosphere (oxygen concentration: 1.00 vol%) in an electric furnace in 2 hours, and then fired at a temperature of 1150 ° C. for 4 hours. Thereafter, the temperature was lowered to 60 ° C. over 4 hours, returned from the nitrogen atmosphere to the atmosphere, and taken out at a temperature of 40 ° C. or lower.
-Process 6 (screening process):
After crushing the agglomerated particles, the low-magnetic force product is cut by magnetic separation, and the coarse particles are removed by sieving with a sieve having an opening of 250 μm, and a 50% particle size (D50) of 37.0 μm based on volume distribution. Magnetic core particles 1 were obtained.

<Adjustment of coating resin 1>
Cyclohexyl methacrylate monomer 26.8% by mass
Methyl methacrylate monomer 0.2% by mass
Methyl methacrylate macromonomer 8.4% by mass
(Macromonomer having a weight average molecular weight of 5000 having a methacryloyl group at one end)
Toluene 31.3% by mass
Methyl ethyl ketone 31.3 mass%
Azobisisobutyronitrile 2.0% by mass
Among the above materials, cyclohexyl methacrylate, methyl methacrylate, methyl methacrylate macromonomer, toluene, methyl ethyl ketone are added to a four-necked separable flask equipped with a reflux condenser, a thermometer, a nitrogen inlet tube and a stirring device, and nitrogen gas is added. Then, the mixture was sufficiently brought to a nitrogen atmosphere, heated to 80 ° C., azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours for polymerization. Hexane was injected into the obtained reaction product to precipitate a copolymer, and the precipitate was filtered off and dried under vacuum to obtain coating 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 content concentration 30%) 33.3% by mass
Toluene 66.4% by mass
Carbon black (Regal 330; manufactured 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)
Was dispersed with a paint shaker for 1 hour using zirconia beads having a diameter of 0.5 mm. The obtained dispersion was filtered through a 5.0 μm membrane filter to obtain a coating resin solution 1.

<Example of production of magnetic carrier 1>
(Resin coating process):
The coating resin solution 1 was added to a vacuum degassing kneader maintained at room temperature so that the resin component was 2.5 parts by mass with respect to 100 parts by mass of the filled core particles 1. After the addition, the mixture was stirred at a rotational speed of 30 rpm for 15 minutes, and after the solvent was volatilized above a certain level (80% by mass), the temperature was raised to 80 ° C. while mixing under reduced pressure. The obtained magnetic carrier is separated by low-magnetization by magnetic separation, passed through a sieve having an opening of 70 μm, and then classified by an air classifier, and a magnetic carrier having a 50% particle size (D50) of 38.2 μm based on volume distribution. 1 was obtained.

<Example of production of two-component developer 1>
To 92.0 parts by mass of magnetic carrier 1, 8.0 parts by mass of toner 1 was added and mixed with a V-type mixer (V-20, manufactured by Seishin Enterprise) to obtain two-component developer 1.

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

<Chargeability evaluation>
Using a Canon full-color copier imagePress C800 as an image forming apparatus, the two-component developer was put in a cyan developing unit of the image forming apparatus and evaluated as described below. The remodeling point is that the mechanism for discharging the excess magnetic carrier inside the developing device from the developing device is removed.
Adjustment was made so that the amount of toner applied on the paper in the FFh image (solid image) was 0.45 mg / cm ² . FFh is a value representing 256 gradations in hexadecimal, 00h is the first gradation (white background part) of 256 gradations, and FF is the 256th gradation (solid part) of 256 gradations. .
In the durability image output test, a durability image output test for 10,000 sheets was performed at an image ratio of 25% in a high temperature and high humidity environment (H / H; temperature 30 ° C., relative humidity 80%). During continuous sheeting of 10,000 sheets, the sheet is passed under the same development conditions and transfer conditions (no calibration) as the first sheet. As the evaluation paper, copy plain paper GF-C081 (A4, basis weight 81.4 g / m ² , sold by Canon Marketing Japan Inc.) was used to output 50,000 sheets of durable images.
The items and evaluation criteria for image output evaluation at the initial stage (first sheet) and when 10,000 sheets are continuously fed 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), initial (first image) and 10,000th FFh image area: solid image density Were measured and ranked according to the following criteria from the difference Δ between the two image densities. 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 effect of the present invention is obtained)
D: 0.20 or more (at a level where the effects of the present invention are not sufficiently obtained).

(2) Measurement of fog In a high-temperature and high-humidity environment (H / H; temperature 30 ° C., relative humidity 80%), the average reflectance Dr (%) of the evaluation paper before image printing is measured by a reflectometer (Tokyo Denshoku Co., Ltd.). It was measured by “REFLECTOMETER MODEL TC-6DS” manufactured by company. Further, the reflectance Ds (%) of the 00h image portion: white background portion of the initial (first sheet) and 10,000th sheet was measured. From the obtained Dr and Ds (initial (first sheet) and 10,000th sheet), fog (%) was calculated using the following formula. The obtained fog value was 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% (at a level where the effects of the present invention are obtained)
D: 2.0% or more (at a level where the effects of the present invention are not sufficiently obtained).

(3) Concentration change after leaving in a high-temperature and high-humidity environment The evaluation machine that has completed the evaluations in (1) and (2) above is directly placed in a high-temperature and high-humidity environment (H / H; temperature 30 ° C., relative humidity 80%). Left for a week. Thereafter, one sheet is printed, and the image density of the FFH image part: solid part is measured in the same manner as in (1), and compared with the image density of the FFH image part: solid part before being left in a high temperature and high humidity environment. From the density difference Δ, ranking was performed 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 (at a level where the effects of the present invention are not sufficiently obtained).

Claims (5)

A toner having toner particles containing a binder resin and inorganic fine powder,
The binder resin contains an amorphous polyester and a 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 cuboid particle shape and a perovskite crystal structure,
In the cross section of the toner by observation with a transmission electron microscope (TEM),
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,
A toner having a maximum value of 50 nm or more and 290 nm or less in a 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.   The toner according to claim 1, wherein the crystalline polyester is obtained by condensation polymerization of an aliphatic diol having 6 to 12 carbon atoms and an aliphatic dicarboxylic acid having 6 to 12 carbon atoms.   The toner according to claim 1, wherein the amorphous polyester is obtained by condensation polymerization of an alcohol component containing 80 mol% or more of a bisphenol propylene oxide adduct and a carboxylic acid component.   The toner according to claim 1, wherein the amorphous polyester is obtained by polycondensing an alcohol component and a carboxylic acid component containing an aliphatic dicarboxylic acid having 4 to 18 carbon atoms.   5. The toner according to claim 3, wherein the propylene oxide adduct of the bisphenol has an average addition mole number of propylene oxide to the bisphenol of 1.6 mol to 3.0 mol.

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