Toner

Abstract

To provide a toner that has good fixability and transferability, and that prevents set-off of a solid image and is excellent in low temperature fixability, and can prevent a deterioration in the transfer efficiency of a solid image in a low temperature and low humidity and a void caused by transfer failure.SOLUTION: A toner has toner particles containing a binder resin and an external additive. (1) The binder resin contains 50 mass% or more of polyester A, and the polyester A contains 90 mol% or more of an isophthalic acid unit Uiso with reference to the total units derived from an acid component. (2) The toner contains titanate fine particles as the external additive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a toner used in an electrophotographic image forming apparatus. [Background technology]

[0002] Electrophotographic devices are being required to be faster and more compact, and to make these possible, further improvements in various performances of toners are being required. For example, toner with good fixability is required to contribute to the speedup and miniaturization of electrophotographic devices. Good fixability allows for fixing to paper with less heat, making it possible to set faster printing speeds. It also contributes to the miniaturization of fixing members. Furthermore, toner with good transferability is also required. This is because less toner remains on the latent image carrier during transfer, which reduces the amount of waste toner collected by the cleaning member, thereby reducing the capacity of the waste toner container. For these reasons, there is a greater demand than ever for improved fixability and transferability of toner. For example, Patent Document 1 discloses a toner containing an amorphous composite resin having a polycondensation resin component obtained by polycondensing an alkylene oxide adduct of bisphenol A with an isophthalic acid compound and an aliphatic saturated carboxylic acid compound, in order to obtain a toner with excellent low-temperature fixing properties. Patent Document 2 discloses a toner in which the state of a release agent and the dynamic viscoelasticity of toner particles are controlled, and further, the ratio of isophthalic acid to the total polycarboxylic acid of a polyester contained as a binder resin is controlled. When such a toner is used, it is possible to suppress the occurrence of offset onto other recording media when writing is performed from the back side of a recording medium on which a solid image has been formed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-003851 [Patent Document 2] Japanese Patent Application Publication No. 2019-049629 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of extensive investigations by the present inventors, it was found that the toner described in Patent Document 1 has a certain improvement effect on low-temperature fixability by using a toner containing a polyester resin having a unit derived from isophthalic acid as a binder resin. Also, the toner described in Patent Document 2 has a certain improvement effect on offset of fixed images due to the high affinity of isophthalic acid with the release agent. However, when the toners described in Patent Documents 1 and 2 are used in a low-temperature, low-humidity environment, there are cases where the transfer efficiency is deteriorated or voids are observed due to poor transfer. [Means for solving the problem]

[0005] In order to solve the above problems, the present inventors have conducted extensive research into the fixability of toner and the contamination resistance of charging members. As a result, they have found that only when toner particles contain a specific amount or more of polyester A containing a certain amount or more of isophthalic acid units and titanate fine particles as an external additive can they achieve both toner fixability (offset of solid images and fixability of halftone images in a low-temperature, low-humidity environment) and transferability (transfer efficiency of solid images and transferability of vertical thin lines). That is, the present disclosure provides a toner having toner particles containing a binder resin and an external additive, 1) The binder resin contains 50% by mass or more of polyester A, and the polyester A contains an isophthalic acid unit U based on the total units derived from the acid component. iso Contains 90 mol% or more of 2) Titanate fine particles are contained as the external additive. The present invention relates to a toner characterized by the above-mentioned. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a toner that satisfies both the fixing and transfer properties of a solid image, that has excellent low-temperature fixing properties, and that can suppress the deterioration of transfer efficiency of a solid image and the occurrence of hollows due to transfer failures in a low-temperature, low-humidity environment. DETAILED DESCRIPTION OF THE INVENTION

[0007] In the present disclosure, unless otherwise specified, the expressions "xx or more and xx or less" and "xx to xx" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints.

[0008] [The process and significance of the present disclosure] As mentioned above, in order to improve the fixability of the toner, the toner particles are provided with an isophthalic acid unit:

[0009] [ka] It is effective to incorporate a polyester rich in bisphenol A as the main component of the binder resin. However, when the process speed of an electrophotographic device is increased, a decrease in transfer efficiency and hollow vertical thin lines may be observed when used in a low-temperature, low-humidity environment. In the present invention, the term "unit" refers to a partial structure present in a polymer. For example, the isophthalic acid unit, as described above, refers to a structure in which an ester bond is formed at the two carboxyl group sites of isophthalic acid. The same applies to the "ethylene oxide adduct unit of bisphenol A" described below, which refers to a structure in which an ester bond is formed at the two hydroxyl group sites of an ethylene oxide adduct of bisphenol A. The same applies to other cases.

[0010] In electrophotography, the transfer process refers to the process of transferring and adhering a toner image formed on the surface of a latent image carrier to paper. To obtain high-quality images, it is important to transfer the toner image formed on the latent image carrier in the development process to paper without any degradation. During the transfer process, a nip is formed between the latent image carrier (photoreceptor) and an intermediate transfer member (intermediate transfer belt) or paper, and a transfer bias is applied to transfer the toner on the latent image carrier to the intermediate transfer member or paper. This can lead to poor transfer, with some of the toner on the latent image carrier remaining on the latent image carrier rather than transferring properly to the intermediate transfer belt or paper. Specifically, this can result in poor transfer efficiency when outputting solid images and voids when outputting vertical thin lines. Increasing the process speed of electrophotographic devices reduces the time required for toner transfer at the nip during the transfer process, placing greater demands on transferability.

[0011] As a result of extensive research, the inventors have found that when toner particles contain a polyester containing an isophthalic acid unit, the electrostatic adhesion of the toner particles increases when printing is performed in a low-temperature, low-humidity environment, resulting in a deterioration in transfer efficiency in solid images and the occurrence of transfer voids in vertical thin line images.

[0012] Although the reason for this is unclear, it is believed to be due to the tendency for the oxygen atoms of the carbonyl group bonded to the benzene ring in the isophthalic acid unit to align, resulting in micro-uneven charge distribution. In low-temperature, low-humidity environments, this charge bias becomes more pronounced, resulting in the formation of countless micro-electric fields on the toner surface due to the uneven charge distribution. It is known that when a micro-electric field exists, an attractive force known as a gradient force is generated, and this attractive force acts strongly on highly insulating surfaces. Therefore, it is believed that toner particles containing polyesters containing isophthalic acid units exhibit a stronger electrostatic adhesion to the latent image carrier.

[0013] Therefore, the present inventors have conducted extensive research into a means for suppressing an increase in the adhesive force between the toner and a latent image carrier in toner particles whose main binder resin component is a polyester containing a large amount of isophthalic acid units. As a result, they have found that by incorporating titanate fine particles, it is possible to achieve both good toner fixability and good toner transferability, and have completed the present disclosure.

[0014] That is, the present disclosure provides a toner having toner particles containing a binder resin and an external additive, 1) The binder resin contains 50% by mass or more of polyester A, and the polyester A contains an isophthalic acid unit U based on the total units derived from the acid component. iso Contains 90 mol% or more of 2) The toner contains titanate fine particles as the external additive. The toner is characterized by the above.

[0015] [Main configuration of the present disclosure] The following mechanism is believed to be the reason why the above-described configuration improves the transferability of the toner. The toner of the present disclosure contains titanate microparticles as an external additive, and the titanate becomes polarized when placed in an electric field. Furthermore, the toner particles of the present disclosure contain a specific amount of polyester A containing a specific amount of isophthalic acid units as a binder resin, resulting in numerous micro-uneven charges caused by the isophthalic acid units. Since micro-uneven charges indicate the presence of a small electric field, the coexistence of isophthalic acid units and titanate microparticles polarizes the titanate microparticles, generating an electric field opposite to the electric field. In this way, the opposite electric field generated by the presence of titanate microparticles cancels out the micro-electric field on the toner, thereby suppressing the generation of gradient forces caused by the small electric field on the toner surface. As a result, it is believed that the increase in electrostatic adhesion is suppressed, improving transferability under low-temperature and low-humidity conditions.

[0016] The polyester A according to the present disclosure comprises a unit U of an ethylene oxide adduct of bisphenol A. EOand the unit U of the propylene oxide adduct of bisphenol A PO and the unit U EO and the unit U PO The total content of the above is preferably 90 mol % or more, based on all units derived from the alcohol component. Ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A are characterized by being easily plasticized by waxes, crystalline polyesters, and the like contained in the toner particles when heated and melted during fixation. Therefore, by having the content within the above range, the binder resin is plasticized when heated and melted during fixation, and is more likely to penetrate into paper fibers. As a result, the adhesion of the toner to paper is further improved, and resistance to image offset and rubbing density reduction is improved, which is preferable.

[0017] Unit U EO Content ratio and unit U PO The unit U EO The content ratio of U EO / (U EO +U PO )×100 is preferably 15 mol % or more and 40 mol % or less.

[0018] Unit U PO is unit U EO It has a larger number of carbon atoms than the unit U and has a branched structure. PO is the unit U EO Conversely, the unit U EO is the unit U PO Compared to U, it has a large polarity. EO / (U EO +U PO When the ratio of U to U is 15 mol % or more, the polarity of polyester A increases, which increases the affinity with paper and suppresses image offset. EO / (U EO +U PO)×100 is 40 mol % or less, the polarity of polyester A is small, and the electrostatic adhesion force caused by the polarity is reduced, thereby improving the transfer efficiency.

[0019] It is preferred that the number average molecular weight (Mn) and weight average molecular weight (Mw) of the tetrahydrofuran (THF) soluble matter of Polyester A, as measured by gel permeation chromatography (GPC), satisfy the following requirements. 3000≦Mn≦10000 Mw / Mn≧2.5

[0020] A number average molecular weight (Mn) of 3,000 or more increases the toughness of the toner after fixing, resulting in good resistance to image offset, while a number average molecular weight (Mn) of 10,000 or less increases the melt fluidity of the binder resin during fixing, making it easier for the binder resin to penetrate into paper fibers, resulting in good resistance to abrasion density loss of the fixed image.

[0021] Furthermore, (Mw / Mn) of 2.5 or more means that the molecular weight distribution of polyester A is sufficiently broad, which increases the melt fluidity at low temperatures and also causes sufficient entanglement of molecular chains, making it easier for the polyester A to penetrate into paper fibers, thereby improving the resistance of the fixed image to a decrease in rubbing density.

[0022] The toner particles preferably contain 0.015% by mass or more and 0.150% by mass or less of aluminum element. By containing 0.015% by mass or more of aluminum element, the toughness is increased due to the crosslinked structure with the resin, and therefore resistance to image set-off is improved. By keeping the content of aluminum element at 0.150% by mass or less, good low-temperature fixability is obtained.

[0023] The aluminum element can be contained in the toner particles by using an aluminum source as an internal additive or a flocculant. In particular, it is preferable to add an aluminum source as a flocculant, since the aluminum element can be ionized in an aqueous medium and then contained in the toner particles, thereby achieving uniformity.

[0024] The binder resin in the present disclosure preferably further contains a crystalline polyester. When the binder resin contains a crystalline polyester, the toner has good low-temperature fixability and good resistance to a decrease in rubbing density of the fixed image. Preferred polyesters as the crystalline polyester will be described later.

[0025] The toner of the present disclosure preferably has an average circularity of 0.950 or more and 0.980 or less. When the average circularity is in this range, the transferability is good under a wide range of environments. Specifically, when the average circularity is 0.950 or more, the contact area between the toner particles and the latent image carrier is reduced, which is preferable because the transfer efficiency is good.

[0026] On the other hand, an average circularity of 0.980 or less is preferable because it improves the rolling property of the toner, suppresses local excessive charge-up, reduces electrostatic adhesion, and improves transferability in low-temperature, low-humidity environments.The average circularity of the toner is more preferably 0.955 or more and 0.975 or less.

[0027] In order to adjust the circularity of the toner within a preferred range, it is preferable to employ a chemical toner manufacturing method such as an emulsion aggregation method, a suspension polymerization method, or a suspension granulation method.

[0028] When the emulsion aggregation method is used, it is preferable to adjust the circularity by providing a spheronization step in order to obtain a desired toner surface shape.

[0029] When the pulverization method is used, the circularity of the toner can be adjusted by subjecting the toner to a surface treatment using hot air in a thermal sphering process.

[0030] The toner of the present disclosure contains titanate particles as an external additive. The titanate particles preferably contain at least one selected from strontium titanate, calcium titanate, and barium titanate. This facilitates polarization of the titanate particles, effectively suppressing the gradient force on the toner surface. This is preferable because it improves transferability in low-temperature, low-humidity environments.

[0031] When the relative dielectric constant of the titanate fine particles of the present disclosure is 100 or more and 2000 or less, polarization of the titanate fine particles is likely to occur, and the gradient force on the toner surface can be effectively suppressed, which is preferable because it improves transferability in low-temperature, low-humidity environments.

[0032] The content of titanate particles in the toner of the present disclosure is preferably 0.01% by mass or more and 5.00% by mass or less. A titanate particle content of 0.01% by mass or more can sufficiently suppress the gradient force resulting from charge unevenness derived from isophthalic acid units, thereby improving transferability in low-temperature, low-humidity environments, which is preferable. Furthermore, a titanate particle content of 5.00% by mass or less is preferable because it can maintain good fixability at low temperatures. In particular, a titanate particle content in the range of 0.1% by mass or more and 1.00% by mass or less is more preferable because it can achieve high levels of both fixability and transferability at low temperatures.

[0033] In the present disclosure, the content of titanate fine particles per 100 parts by mass of toner particles is represented by A (parts by mass), and the isophthalic acid unit U is represented by the total units derived from the acid component constituting polyester A. iso When the content ratio of polyester A contained in the binder resin is B (mol %) and the content ratio of polyester A contained in the binder resin is C (mass %), it is preferable that A, B and C satisfy the following formula: 1.0×10 -5 ≦A / (B×C)≦1.1×10 -4 (1)

[0034] A / (B×C) is 1.0×10 -5In this case, a sufficient amount of titanate is present relative to the isophthalic acid units contained in the toner particles, resulting in good transferability. -5 When A / (B×C) is 3.1×10, the fixing property at low temperature can be maintained favorably. -5 Over 4.3 x 10 -5 When the amount is in the following range, both the fixability and the transferability can be achieved at a high level, which is more preferable.

[0035] It is preferable that the surface of the titanate particles is treated with a silane coupling agent or a fatty acid, since the surface energy of the titanate particles is reduced, thereby reducing the adhesive force of the toner, thereby improving the transfer efficiency.

[0036] [Preferred Constituents and Forms of Toner] Next, preferred components and embodiments of the toner according to the present disclosure will be described.

[0037] <Binder resin> The toner particles contain a binder resin.

[0038] As described above, the binder resin must contain 50% by mass or more of polyester A. When the content is 70% by mass or more, the fixability is improved. In addition, the interaction with the titanate particles is enhanced, which is preferable because it also improves the transferability in a low-temperature, low-humidity environment.

[0039] The binder resin may also contain a resin other than polyester A, such as a styrene acrylic resin, an epoxy resin, a polyester, a polyurethane, a polyamide, a cellulose resin, a polyether resin, or a mixed or composite resin thereof.

[0040] <Polyester A> As described above, polyester A has a ratio of isophthalic acid units U based on the total units derived from the acid component. iso The content is 90 mol % or more.

[0041] The polyester A is preferably an amorphous polyester.

[0042] Polyester A may contain an isophthalic acid unit as an essential component. The polyester can be obtained by selecting and combining suitable components from polycarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, etc., and synthesizing them using a known method such as transesterification or polycondensation. Preferably, the polyester contains a condensation polymer of a dicarboxylic acid and a diol.

[0043] Polycarboxylic acids are compounds containing two or more carboxy groups in one molecule, and among these, dicarboxylic acids are compounds containing two carboxy groups in one molecule and are preferably used.

[0044] Examples of the carboxylic acids include oxalic acid, succinic acid, glutaric acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, hexahydroterephthalic acid, malonic acid, pimelic acid, suberic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, o-phenylenediacetic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, and cyclohexanedicarboxylic acid.

[0045] Furthermore, examples of polycarboxylic acids other than the above dicarboxylic acids include trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, pyrenetetracarboxylic acid, itaconic acid, glutaconic acid, n-dodecylsuccinic acid, n-dodecenylsuccinic acid, isododecylsuccinic acid, isododecenylsuccinic acid, n-octylsuccinic acid, n-octenylsuccinic acid, etc. These may be used alone or in combination of two or more.

[0046] A polyol is a compound containing two or more hydroxyl groups in one molecule, and a diol is a compound containing two hydroxyl groups in one molecule.

[0047] Specifically, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanediol. Examples of suitable bisphenols include hexanediol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-butenediol, neopentyl glycol, polytetramethylene glycol, hydrogenated bisphenol A, bisphenol A, bisphenol F, bisphenol S, and alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts of the above bisphenols.

[0048] Among these, alkylene oxide adducts of bisphenols and alkylene glycols having from 2 to 12 carbon atoms are preferred, and alkylene oxide adducts of bisphenols and their combined use with alkylene glycols having from 2 to 12 carbon atoms are particularly preferred. Examples of alkylene oxide adducts of bisphenol A include compounds represented by the following formula (A):

[0049] [ka] (In formula (A), each R is independently 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 0 or more and 10 or less.)

[0050] The alkylene oxide adduct of bisphenol A is preferably a propylene oxide adduct and / or an ethylene oxide adduct of bisphenol A. It is more preferably a propylene oxide adduct. The average value of x+y is preferably 1 or more and 5 or less.

[0051] Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, sorbitol, trisphenol PA, phenol novolac, cresol novolac, alkylene oxide adducts of the above trihydric or higher polyphenols, etc. These may be used alone or in combination of two or more.

[0052] The acid value of the polyester A is preferably 4.0 mgKOH / g or more and 10.0 mgKOH / g or less.

[0053] <Release agent> A known release agent can be used in the toner.

[0054] Specific examples include petroleum waxes and derivatives thereof, such as paraffin wax, microcrystalline wax, and petrolatum, montan wax and derivatives thereof, hydrocarbon waxes produced by the Fischer-Tropsch process and derivatives thereof, polyolefin waxes and derivatives thereof, such as polyethylene, and natural waxes and derivatives thereof, such as carnauba wax and candelilla wax, and derivatives thereof, and derivatives thereof also include oxides, block copolymers with vinyl monomers, and graft modified products.

[0055] Other examples include alcohols such as higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid or their acid amides, esters, and ketones, hydrogenated castor oil and its derivatives, vegetable waxes, and animal waxes.These can be used alone or in combination.

[0056] Among these, polyolefins, hydrocarbon waxes produced by the Fischer-Tropsch process, or petroleum-based waxes are preferred because they tend to improve developability and transferability. These waxes may contain an antioxidant within a range that does not affect the effects of the toner. From the viewpoint of phase separation with respect to the binder resin or crystallization temperature, preferred examples include higher fatty acid esters such as behenyl behenate and dibehenyl sebacate.

[0057] The content of the release agent is preferably 1.0 part by mass or more and 30.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

[0058] The melting point of the release agent is preferably 30° C. or higher and 120° C. or lower, and more preferably 60° C. or higher and 100° C. or lower. By using a release agent having the above-mentioned thermal properties, the release effect is efficiently exerted and a wider fixing area is secured.

[0059] <Plasticizer> The toner particles may contain a crystalline plasticizer to improve sharp melting properties. The plasticizer is not particularly limited, and known plasticizers used in toners such as those described below can be used.

[0060] Specifically, esters of monohydric alcohols and aliphatic carboxylic acids, such as behenyl behenate, stearyl stearate, and palmityl palmitate, or esters of monohydric carboxylic acids and aliphatic alcohols; esters of dihydric alcohols and aliphatic carboxylic acids, such as ethylene glycol distearate, dibehenyl sebacate, and hexanediol dibehenate, or esters of dihydric carboxylic acids and aliphatic alcohols; esters of trihydric alcohols and aliphatic carboxylic acids, such as glycerin tribehenate, or esters of trihydric carboxylic acids and aliphatic alcohols; pentaerythritol tetrastearate Examples of suitable esters include esters of tetrahydric alcohols and aliphatic carboxylic acids, such as dipentaerythritol hexastearate and pentaerythritol tetrapalmitate, or esters of tetrahydric carboxylic acids and aliphatic alcohols; esters of hexahydric alcohols and aliphatic carboxylic acids, such as dipentaerythritol hexastearate and dipentaerythritol hexapalmitate, or esters of hexahydric carboxylic acids and aliphatic alcohols; esters of polyhydric alcohols and aliphatic carboxylic acids, such as polyglycerol behenate, or esters of polyhydric carboxylic acids and aliphatic alcohols; and natural ester waxes, such as carnauba wax and rice wax. These may be used alone or in combination.

[0061] <Crystalline polyester> The toner particles preferably contain a crystalline polyester as a part of the binder resin. The crystalline polyester is preferably a condensation polymer of a monomer containing an aliphatic diol and / or an aliphatic dicarboxylic acid. The crystalline polyester refers to a polyester that has a clear melting point as measured by a differential scanning calorimeter (DSC).

[0062] The crystalline polyester preferably contains an aliphatic diol unit having 2 or more and 12 or less carbon atoms (more preferably 6 or more and 12 or less) and / or an aliphatic dicarboxylic acid unit having 2 or more and 12 or less carbon atoms (more preferably 6 or more and 12 or less).

[0063] A crystalline polyester having such a structure is preferred because it improves the dispersibility of the crystalline polyester between toner particles, suppresses uneven wetting and spreading between toner particles during fixing, and improves the temperature fixing property.

[0064] Examples of the aliphatic diol having 2 to 12 carbon atoms include the following compounds.

[0065] 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol. Aliphatic diols having double bonds can also be used. Examples of aliphatic diols having double bonds include the following compounds: 2-butene-1,4-diol, 3-hexene-1,6-diol, and 4-octene-1,8-diol. Examples of aliphatic dicarboxylic acids having 2 to 12 carbon atoms include the following compounds: Examples of suitable aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, and 1,12-dodecanedicarboxylic acid. Lower alkyl esters and acid anhydrides of these aliphatic dicarboxylic acids can also be used. Among these, sebacic acid, adipic acid, and 1,10-decanedicarboxylic acid, as well as their lower alkyl esters and acid anhydrides, are preferred. These may be used alone or in combination. Aromatic dicarboxylic acids can also be used. Examples of aromatic dicarboxylic acids include the following: terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. Among these, terephthalic acid is preferred due to its availability and ability to easily form low-melting polymers.

[0066] Furthermore, dicarboxylic acids having double bonds can also be used, which can be suitably used to suppress hot offset during fixing, since the double bonds can be used to crosslink the entire resin.

[0067] Examples of such dicarboxylic acids include fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Also included are lower alkyl esters and acid anhydrides of these acids. Among these, fumaric acid and maleic acid are more preferred.

[0068] The method for producing the crystalline polyester is not particularly limited, and the crystalline polyester can be produced by a general polyester polymerization method in which a dicarboxylic acid component and a diol component are reacted. For example, the crystalline polyester can be produced by a direct polycondensation method or an ester exchange method, which are selected depending on the type of monomer.

[0069] The peak temperature of the maximum endothermic peak of the crystalline polyester measured using a differential scanning calorimeter (DSC) is preferably 50.0°C or higher and 100.0°C or lower, and from the viewpoint of low-temperature fixability, more preferably 60.0°C or higher and 90.0°C or lower. From the viewpoint of low-temperature fixability, the acid value of the crystalline polyester is preferably 2 mgKOH / g or higher and 3 mgKOH / g or lower. The Mn of the crystalline polyester is preferably 10,000 or higher and 14,000 or lower. From the viewpoint of the balance between low-temperature fixability and transferability, the content of the crystalline polyester in the toner is preferably 3.0% by mass or higher and 30.0% by mass or lower.

[0070] <Titanate fine particles> The toner of the present disclosure contains titanate microparticles. By including titanate microparticles, the charge unevenness caused by the isophthalic acid units can be counteracted by the polarization of the titanate microparticles. This suppresses the increase in gradient force in low-temperature, low-humidity environments, which is caused by the charge unevenness caused by the isophthalic acid units. Furthermore, since the electric field caused by the charge unevenness caused by the isophthalic acid units and the electric field caused by the polarization of the titanate microparticles are generated in opposite directions, the titanate microparticles can remain in close proximity to the isophthalic acid units during the electrophotographic process, thereby maintaining this effect. Therefore, the coexistence of the isophthalic acid units and the titanate microparticles ensures that transferability is not lost even during a certain amount of printing, resulting in good print quality.

[0071] The type of titanate particles constituting the titanate particles can be used without any particular limitation. Examples include beryllium titanate particles, magnesium titanate particles, calcium titanate particles, strontium titanate particles, barium titanate particles, radium titanate particles, potassium titanate particles, and lead titanate particles. Among these, strontium titanate particles, calcium titanate particles, and barium titanate particles are preferred because they facilitate polarization of the particles, effectively suppress the gradient force on the toner surface, and improve transferability in low-temperature, low-humidity environments. In particular, strontium titanate particles are more preferred because they are excellent at improving transferability in low-temperature, low-humidity environments.

[0072] When the relative dielectric constant of the titanate particles is 100 or more and 2000 or less, the titanate particles are easily polarized, the gradient force on the toner surface can be effectively suppressed, and the transferability in a low-temperature, low-humidity environment can be improved, which is preferable.

[0073] Although the particle size and shape of the titanate particles are not particularly limited, a number-average particle size of the primary particles of 300 nm or less is preferred because the large specific surface area allows for efficient interaction with the isophthalic acid units, thereby suppressing charge unevenness on the toner surface. Furthermore, a number-average particle size of the primary particles of 30 nm or more is preferred because the titanate particles act as spacers, reducing the contact area between the toner and the latent image carrier and improving transferability.

[0074] Titanate microparticles whose surfaces have been treated with a known surface treatment agent may be used. Examples of the surface treatment agent include fatty acids, fatty acid metal salts, silane coupling agents, silicone oils, and the like. The fatty acids are not particularly limited as long as they have a structure in which a hydrocarbon group and a carboxy group are bonded, but fatty acids in which an alkyl group having 12 to 28 carbon atoms is bonded to a carboxy group are preferred. Metal salts of these may also be used.

[0075] Silane coupling agents include n-octyltriethoxysilane, methyltrimethoxysilane, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, and chloromethyldimethylchlorosilane. , triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and having one hydroxyl group on each of the Si units located at the terminals. These can be used alone or in a mixture of two or more.

[0076] Examples of silicone oils include dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

[0077] The surface treatment agent for the titanate fine particles may be any of the above treatment agents, which may be used alone or in combination of two or more. In particular, the use of a silane coupling agent or a fatty acid as the surface treatment agent for the titanate fine particles is preferred because it can suppress adhesion and improve transfer efficiency.

[0078] <Coloring agent> The toner particles may contain a colorant. Known pigments and dyes can be used as the colorant. Pigments are preferred because of their excellent weather resistance. Examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specific examples include the following: CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0079] Magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254, and CI Pigment Violet 19.

[0080] Yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185, 191, and 194.

[0081] Examples of black colorants include those toned to black using the above-mentioned yellow, magenta, and cyan colorants, as well as carbon black and magnetic materials. These colorants can be used alone, as a mixture, or in the form of a solid solution. The colorant is preferably used in an amount of 1.0 to 20.0 parts by mass per 100.0 parts by mass of binder resin. When using a magnetic material in the manufacturing method in an aqueous medium described below, it is preferable to perform a hydrophobic treatment to stably incorporate the magnetic material into the resin.

[0082] <Charge control agents and charge control resins> The toner particles may contain a charge control agent or a charge control resin. Known charge control agents can be used, and charge control agents that have a high triboelectric charging speed and can stably maintain a constant triboelectric charge amount are particularly preferred. Furthermore, when the toner particles are produced by a suspension polymerization method, charge control agents that have low polymerization inhibition properties and are substantially free of solubilized substances in aqueous media are particularly preferred.

[0083] Examples of substances that control the toner to be negatively charged include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic and dicarboxylic acid-based metal compounds, aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid-based compounds, metal-containing naphthoic acid-based compounds, boron compounds, quaternary ammonium salts, calixarene, and charge control resins.

[0084] Examples of the charge control resin include polymers or copolymers having sulfonic acid groups, sulfonate salt groups, or sulfonate ester groups. As the polymer having sulfonic acid groups, sulfonate salt groups, or sulfonate ester groups, a polymer containing 2% by mass or more, more preferably 5% by mass or more, of a sulfonate group-containing acrylamide monomer or a sulfonate group-containing methacrylamide monomer in copolymerization ratio is preferred.

[0085] The charge control resin preferably has a glass transition temperature (Tg) of 35°C or higher and 90°C or lower, a peak molecular weight (Mp) of 10,000 or higher and 30,000 or lower, and a weight average molecular weight (Mw) of 25,000 or higher and 50,000 or lower. When used, it can impart desirable triboelectric charging properties without affecting the thermal properties required of the toner particles. Furthermore, when the charge control resin contains sulfonic acid groups, the dispersibility of the charge control resin itself and the dispersibility of colorants, etc., in the polymerizable monomer composition is improved, thereby further improving coloring power, transparency, and triboelectric charging properties.

[0086] These charge control agents or charge control resins may be added alone or in combination of two or more. The amount of charge control agent or charge control resin added is preferably 0.01 parts by mass or more and 20.0 parts by mass or less, and more preferably 0.5 parts by mass or more and 10.0 parts by mass or less, relative to 100.0 parts by mass of binder resin.

[0087] [Toner manufacturing method] The method for producing the toner is not particularly limited, and known methods such as a pulverization method, a suspension polymerization method, a solution suspension method, an emulsion aggregation method, and a dispersion polymerization method can be used. Here, the toner is preferably produced by the following method. That is, the toner is preferably produced by an emulsion aggregation method.

[0088] When producing by the emulsion aggregation method, the following steps (1) to (3) are performed: (1) a dispersion step of preparing a binder resin particle dispersion containing the binder resin; (2) an aggregating step of aggregating the binder resin fine particles contained in the binder resin fine particle dispersion to form aggregates; and (3) a fusion step of heating the aggregates to fuse them together and, during or after the fusion step, the following steps (4) to (6): (4) a spheronization step of further heating the agglomerates at an elevated temperature; (5) a cooling step of cooling the aggregate at a cooling rate of 0.1°C / second or more; and (6) an annealing step of heating and maintaining the aggregate at a temperature equal to or higher than the crystallization temperature or the glass transition temperature of the binder resin; It is preferable to have these in this order.

[0089] The emulsion aggregation method is preferred in that the polyester A can be easily dispersed uniformly in the vicinity of the surface of the toner particles and the toner shape can be easily controlled. The emulsion aggregation method will be described in detail below.

[0090] <Emulsification aggregation method> The emulsion aggregation method is a method of producing toner particles by preparing in advance an aqueous dispersion of fine particles made of the constituent materials of toner particles that are sufficiently small relative to the target particle size, aggregating the fine particles in an aqueous medium until they reach the particle size of toner particles, and fusing the resin by heating or the like.

[0091] That is, in the emulsion aggregation method, toner particles are manufactured through a series of steps: a dispersion process in which a fine particle dispersion liquid made up of the constituent materials of toner particles is prepared; an aggregation process in which fine particles made up of the constituent materials of toner particles are aggregated and the particle size is controlled until the particle size reaches that of toner particles; a fusion process in which the resin contained in the resulting aggregated particles is fused; a spheronization process in which the particles are melted by heating or the like and the surface shape of the toner is controlled; a subsequent cooling process; a metal removal process in which the resulting toner is filtered and excess polyvalent metal ions are removed; a filtration and washing process in which the toner is washed with ion-exchanged water or the like; and a process in which the washed toner particles are dehydrated and dried.

[0092] "Process for preparing a resin particle dispersion (dispersion process)" The resin particle dispersion can be prepared by a known method, but is not limited to these methods. Examples of known methods include emulsion polymerization, self-emulsification, phase inversion emulsification in which a resin is emulsified by adding an aqueous medium to a resin solution dissolved in an organic solvent, and forced emulsification in which a resin is forcibly emulsified by high-temperature treatment in an aqueous medium without using an organic solvent.

[0093] Specifically, the binder resin is dissolved in an organic solvent capable of dissolving it, and a surfactant and a basic compound are added. If the binder resin is a crystalline resin with a melting point, it can be dissolved by heating it above the melting point. Subsequently, an aqueous medium is slowly added while stirring with a homogenizer or the like to precipitate resin microparticles. The solvent is then removed by heating or reducing pressure to prepare an aqueous dispersion of resin microparticles. Any organic solvent capable of dissolving the resin can be used to dissolve the resin, but it is preferable to use an organic solvent that forms a homogeneous phase with water, such as toluene, in order to prevent the generation of coarse particles.

[0094] The surfactant used during the emulsification is not particularly limited, but examples thereof include anionic surfactants such as sulfate ester salts, sulfonate salts, carboxylate salts, phosphate esters, and soap-based surfactants; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. The surfactants may be used alone or in combination of two or more.

[0095] Examples of the basic compound used in the dispersion step include inorganic bases such as sodium hydroxide and potassium hydroxide, and organic bases such as ammonia, triethylamine, trimethylamine, dimethylaminoethanol, and diethylaminoethanol. The basic compound may be used alone or in combination of two or more.

[0096] Furthermore, the 50% particle diameter (D50) of the binder resin particles in the aqueous dispersion of resin particles is preferably 0.05 μm to 1.0 μm, more preferably 0.05 μm to 0.4 μm. By adjusting the 50% particle diameter (D50) of the volume distribution to fall within the above range, it becomes easy to obtain toner particles with a volume average particle diameter of 3 μm to 10 μm, which is an appropriate size for toner particles.

[0097] The 50% particle size (D50) based on volume distribution is measured using a dynamic light scattering particle size distribution analyzer Nanotrac UPA-EX150 (manufactured by Nikkiso).

[0098] "Colorant particle dispersion" A colorant particle dispersion may be used as needed. The colorant particle dispersion can be prepared by the following known methods, but is not limited to these. It can be prepared by mixing a colorant, an aqueous medium, and a dispersant using a known mixer such as a stirrer, an emulsifier, or a disperser. The dispersant used here can be a known one such as a surfactant or a polymer dispersant.

[0099] Both surfactants and polymer dispersants can be removed in the washing step described below, but surfactants are preferred from the viewpoint of washing efficiency.

[0100] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soap-based surfactants; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, nonionic surfactants or anionic surfactants are preferred. Nonionic surfactants and anionic surfactants may also be used in combination. The surfactants may be used alone or in combination of two or more. The concentration of the surfactant in the aqueous medium is preferably 0.5% by mass or more and 5% by mass or less.

[0101] The content of the colorant particles in the colorant particle dispersion is not particularly limited, but is preferably 1% by mass or more and 30% by mass or less relative to the total mass of the colorant particle dispersion.

[0102] From the viewpoint of dispersibility of the colorant in the final toner, the dispersed particle size of the colorant particles in the aqueous dispersion of the colorant is preferably 0.5 μm or less in terms of the 50% particle size (D50) based on volume distribution. For the same reason, it is also preferable that the 90% particle size (D90) based on volume distribution is 2 μm or less. The dispersed particle size of the colorant particles dispersed in the aqueous medium is measured using a dynamic light scattering particle size distribution analyzer (Nanotrac UPA-EX150, manufactured by Nikkiso).

[0103] Known mixers such as stirrers, emulsifiers, and dispersers used when dispersing a colorant in an aqueous medium include ultrasonic homogenizers, jet mills, pressure homogenizers, colloid mills, ball mills, sand mills, and paint shakers. These may be used alone or in combination.

[0104] "Release agent (aliphatic hydrocarbon compound) fine particle dispersion" If necessary, a dispersion of fine particles of a releasing agent may be used. The dispersion of fine particles of a releasing agent can be prepared by the following known methods, but is not limited to these methods.

[0105] A release agent microparticle dispersion can be produced by adding the release agent to an aqueous medium containing a surfactant, heating the mixture to above the melting point of the release agent, dispersing the mixture into particles using a homogenizer with strong shearing capabilities (such as the Clearmix W Motion manufactured by M Technique) or a pressure discharge type disperser (such as the Gaulin Homogenizer manufactured by Gaulin), and then cooling the mixture to below the melting point of the release agent.

[0106] The particle size of the dispersed particulate release agent in the aqueous dispersion of the release agent is preferably 0.03 μm or more and 1.0 μm or less, and more preferably 0.1 μm or more and 0.5 μm or less, in terms of the 50% particle size (D50) based on volume distribution. It is also preferable that no coarse particles of 1 μm or more exist.

[0107] By setting the dispersed particle size of the release agent particle dispersion within the above range, it becomes possible to finely disperse the release agent in the toner, maximize the exudation effect during fixing, and obtain good separability. The dispersed particle size of the release agent particle dispersion dispersed in the aqueous medium can be measured using a dynamic light scattering particle size distribution analyzer (Nanotrac UPA-EX150: manufactured by Nikkiso).

[0108] "Mixing process" In the mixing step, a mixture is prepared by mixing the resin particle dispersion and, if necessary, at least one of the release agent particle dispersion and the colorant particle dispersion, which can be carried out using a known mixing device such as a homogenizer or a mixer.

[0109] <Step of forming aggregate particles (aggregation step)> In the aggregating step, the fine particles contained in the mixed solution prepared in the mixing step are aggregated to form aggregates of a desired particle size. At this time, an aggregating agent is added and mixed, and at least one of heat and mechanical power is applied as needed to form aggregates in which the resin fine particles and, if necessary, at least one of the release agent fine particles and the colorant fine particles are aggregated.

[0110] Examples of flocculants include monovalent metal salts such as thorium and potassium, divalent metal salts such as calcium and magnesium, trivalent metal salts such as iron and aluminum, and alcohols such as methanol, ethanol, and propanol.Preferably, the flocculant contains a divalent or higher metal element that has high coagulation power and can cause coagulation with the addition of a small amount.

[0111] Specific examples include divalent inorganic metal salts such as calcium chloride, calcium nitrate, magnesium chloride, magnesium sulfate, and zinc chloride. Other examples include trivalent metal salts such as iron(III) chloride, iron(III) sulfate, aluminum sulfate, and aluminum chloride. Other examples include inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, polyferric sulfate, and calcium polysulfide, but are not limited to these. These may be used alone or in combination of two or more. Aluminum metal salts are preferred from the viewpoint of controlling the amount of aluminum element in the toner particles. It is also possible to add an acid to lower the pH and cause soft aggregation; for example, sulfuric acid or nitric acid can be used.

[0112] The aggregating agent may be added in the form of either a dry powder or an aqueous solution dissolved in an aqueous medium. However, to induce uniform aggregation, it is preferable to add it in the form of an aqueous solution. The addition and mixing of the aggregating agent is preferably carried out at a temperature below the glass transition temperature or melting point of the resin contained in the mixed liquid. Mixing under these temperature conditions allows for relatively uniform aggregation. The aggregating agent can be mixed into the mixed liquid using a known mixing device such as a homogenizer or mixer. The aggregation process is a process in which aggregates of the same size as toner particles are formed in an aqueous medium. The volume average particle size of the aggregates produced in the aggregation process is preferably 3 μm or more and 10 μm or less. The volume average particle size can be measured using a particle size distribution analyzer (Coulter Multisizer III, manufactured by Coulter) using the Coulter method.

[0113] "Process for obtaining a dispersion liquid containing toner particles (fusion process)" In the fusion step, the dispersion containing the aggregates obtained in the aggregation step is first subjected to termination of aggregation under stirring in the same manner as in the aggregation step by adding an aggregation terminator such as a base capable of adjusting the pH, a chelating compound, or an inorganic salt compound such as sodium chloride.

[0114] After the dispersion state of the aggregated particles in the dispersion liquid becomes stable due to the action of the aggregation terminator, the dispersion is heated to a temperature equal to or higher than the glass transition temperature or melting point of the binder resin to fuse the aggregated particles and adjust them to the desired particle size.

[0115] The 50% particle size (D50) of the toner particles based on volume distribution is preferably 3 μm or more and 10 μm or less.

[0116] "Process for obtaining the desired toner surface shape (sphericization process)" During or after the fusion step, it is preferable to carry out a spheronization step in which the temperature is further increased and maintained until the toner particles reach a desired circularity or surface shape. Specific temperatures for the spheronization step are, for example, 90° C. or higher, preferably 92° C. or higher, and preferably 95° C. or lower. The heating time for the spheronization step can be, for example, 3 hours or more, 5 hours or more, or 8 hours or more.

[0117] "Cooling process" After the spheronization step, a cooling step is preferably performed in which the temperature of the dispersion containing the obtained toner particles is cooled to a temperature lower than the crystallization temperature or glass transition temperature of the binder resin by controlling the cooling rate. By performing the cooling step, the formation of irregularities on the toner particle surface due to volume changes such as expansion or contraction of the materials in the toner particles can be suppressed. A specific cooling rate is 0.1°C / sec or more, preferably 0.5°C / sec or more, more preferably 2°C / sec or more, and even more preferably 4°C / sec or more.

[0118] <Annealing process> After the cooling step, it is preferable to carry out an annealing step in which the toner particles are heated and maintained at a temperature equal to or higher than the crystallization temperature or glass transition temperature of the binder resin, and, if a release agent is contained, equal to or lower than the crystallization temperature of the release agent. By carrying out the annealing step, volume change can be further suppressed, thereby suppressing the occurrence of depressions on the toner particle surface. Therefore, the desired circularity or surface shape obtained through the cooling step can be maintained. The specific annealing temperature is 45°C or higher and 75°C or lower, preferably 50°C or higher and 70°C or lower, and more preferably 55°C or higher and 65°C or lower. The heat treatment time in the annealing step is, for example, within 5 hours, preferably 2 to 3 hours.

[0119] "Post-processing process" In the toner production method, post-treatment steps such as a washing step, a solid-liquid separation step, and a drying step may be further carried out, and by carrying out the post-treatment steps, toner particles in a dried state can be obtained.

[0120] <External addition process> Titanate fine particles are externally added to the toner particles obtained as described above. If necessary, other conventionally known fine particles may be used in combination.

[0121] The amount of titanate microparticles added may be 0.01 parts by mass or more and 5.00 parts by mass or less per 100 parts by mass of toner particles, but it is more preferable that the amount be 0.1 parts by mass or more and 1.0 part by mass or less, since this allows the toner to achieve both high levels of fixability and transferability.

[0122] The toner of the present disclosure may contain other external additives in addition to the titanate fine particles.

[0123] Other external additives can be used without any particular limitations, and conventionally known external additives can be used alone or in combination.In addition, the particle size of the external additive can be used without any particular limitations, and external additives of different particle sizes can be used in combination.Specific examples include raw silica fine particles such as wet-process silica and dry-process silica, surface-treated silica fine particles obtained by surface-treating these raw silica fine particles with a treatment agent such as a silane coupling agent, a titanium coupling agent, or silicone oil, and resin fine particles such as vinylidene fluoride fine particles and polytetrafluoroethylene fine particles.When surface-treated silica is used in combination with titanate fine particles as an external additive, it is preferable because it improves transferability.

[0124] The content of the other external additives is preferably 0.1 parts by mass or more and 5.0 parts by mass or less with respect to 100.0 parts by mass of the toner particles.

[0125] [Methods for measuring physical properties] Next, the methods for measuring the various physical properties according to the present disclosure will be described.

[0126] <Method for isolating toner particles and titanate fine particles, and method for measuring the content of titanate fine particles in toner> A dispersion medium is prepared by adding 0.50 g of Triton-X100 (Kishida Chemical Co., Ltd.) to 100 g of ion-exchanged water. (1) 1.00 g of toner is accurately weighed into a vial, and the dispersion medium is added to make the total weight 10.00 g, and the solution is left to stand for 24 hours to prepare a sample liquid. (2) The sample liquid is subjected to an ultrasonic homogenizer treatment to liberate the external additives from the toner and disperse them in the dispersion medium. Ultrasonic treatment device: Ultrasonic homogenizer VP-050 (manufactured by Taitec Co., Ltd.) Microchip: Stepped microchip, tip diameter 2mm Microchip tip position: Center of glass vial, 5 mm above the bottom of the vial Ultrasonic conditions: intensity 30%, 180 minutes. During this time, ultrasonic waves are applied while cooling the vial with ice water to prevent the dispersion from heating up. (3) The toner particles in the sample liquid are separated from the dispersion medium in which the external additives are dispersed by suction filtration (10 μm membrane filter) (filtrate). (4) The toner particles after filtration are collected, and the dispersion medium is added again to make the total weight 10.00 g. Then, the above steps (2) and (3) are repeated 10 times, and all the filtrate is collected. (5) If other external additives are added, the recovered filtrate is centrifuged to separate the other external additives and recover the titanate fine particles. (6) The collected titanate microparticles were thoroughly dried in a vacuum dryer at 60°C for 24 hours to isolate the dried titanate microparticles.

[0127] The mass of the titanate particles after drying was measured to determine the mass of the titanate particles contained in 1.00 g of toner, and the mass was multiplied by 100 to determine the content (mass %) of the titanate particles in the toner.

[0128] <Method for isolating toner particles> In (4) of the method for isolating toner particles and titanate microparticles, and the method for measuring the content of titanate microparticles in the toner, the filtration was repeated a total of 10 times to recover the toner particles, which were then thoroughly dried at 45°C for 24 hours to isolate the toner particles.

[0129] <Method for isolating binder resin from toner particles> 100 mg of toner particles were dissolved in 3 mL of chloroform. Next, insoluble matter was removed by suction filtration using a syringe equipped with a sample processing filter (pore size 0.2 μm to 0.5 μm, such as a Myshoridisk H-25-2 (Tosoh Corporation)). The soluble matter was introduced into a preparative HPLC (apparatus: Japan Analytical Industry Co., Ltd. LC-9130 NEXT preparative column [60 cm], exclusion limits: 20,000 and 70,000, two columns connected), and chloroform eluent was pumped. Once a peak was confirmed in the resulting chromatographic display, fractions with retention times of molecular weights of 2,000 or higher were collected using a monodisperse polystyrene standard sample. The solution of the obtained fraction is dried and solidified to separate it from the release agent and separate the binder resin.

[0130] <Composition analysis of multiple components (polyester A, crystalline polyester)> The chloroform-soluble portion of the separated binder resin is used as the sample. The sample is adjusted with chloroform so that the toner particle concentration is 0.1% by mass, and the solution is filtered through a 0.45 μm PTFE filter before being used for measurement. The gradient polymer LC measurement conditions are as follows:

[0131] Equipment: UlTIMATE3000 (Thermo Fisher Scientific) Mobile phase: A chloroform (HPLC), B acetonitrile (HPLC) Gradient: 2 min (A / B = 0 / 100) → 25 min (A / B = 100 / 0) (Note: The gradient of the mobile phase change was made linear.) Flow rate: 1.0mL / min Injection: 0.1% by mass x 20μL Column: Tosoh TSKgel ODS (4.6mmφ x 150mm x 5μm) Column temperature: 40℃ Detector: Corona Charged Aerosol Detector (Corona-CAD) (Thermo Fisher Scientific) Polyester A is separated at a time corresponding to polyester A (7 minutes to 9 minutes). Crystalline polyester is also separated at a time corresponding to crystalline polyester (13 minutes to 15 minutes). In the fractionation, the required amount of each chloroform / acetonitrile solution is collected, dried, and concentrated to give samples of polyester A and crystalline polyester.

[0132] Using samples of polyester A and crystalline polyester, the composition ratio and mass ratio are measured by nuclear magnetic resonance spectroscopy (NMR) as follows.

[0133] Add 1 mL of deuterated chloroform to 20 mg of the sample (Polyester A, crystalline polyester), and measure the NMR spectrum of the protons of the dissolved resin. From the obtained NMR spectrum, the molar ratio and mass ratio of each monomer can be calculated by regarding the smallest unit sandwiched by ester bonds as the structure derived from the monomer (acid component, alcohol component), and the content ratio of each monomer unit can be determined.

[0134] For nuclear magnetic resonance spectroscopy (NMR), the following apparatuses and measurement conditions can be used. NMR apparatus: RESONANCE ECX500 manufactured by JEOL Ltd. Observed nucleus: proton Measurement mode: single pulse

[0135] <Quantification method for the content of U iso in Polyester A by NMR measurement EO U PO > · Identification of components of Polyester A and measurement of molar ratio and mass ratio by nuclear magnetic resonance spectroscopy (NMR) Add 1 mL of deuterated chloroform to 20 mg of the obtained Polyester A, and measure the NMR spectrum of the protons of the dissolved Polyester A. The molar ratio and mass ratio of each monomer were calculated from the obtained NMR spectrum.

[0136] For example, the composition ratio and mass ratio can be calculated based on the following peaks (chemical shift value, number of protons).

[0137] Unit derived from isophthalic acid: 7.5 ppm (1), 8.2 ppm (2), 8.7 ppm (1) Unit derived from terephthalic acid: 8.1 ppm (4) Unit derived from ethylene oxide adduct of bisphenol A: 1.6 ppm (6), 4.3 ppm (4), 4.7 ppm (4), 6.8 ppm (4), 7.1 ppm (4) Units derived from propylene oxide adducts of bisphenol A: 1.5 ppm (6), 1.6 ppm (6), 4.1 ppm (4), 5.5 ppm (2), 6.8 ppm (4), 7.1 ppm (4) Ethylene glycol derived units: 4.3 ppm (4) NMR device: JEOL RESONANCE ECX500 Observation nucleus: Proton Measurement mode: Single pulse Base peak: TMS

[0138] NMR analysis revealed that the isophthalic acid unit U based on the total units derived from the acid component iso The content (mol%) of U was calculated based on the total units derived from the alcohol component. EO and U PO The total content (mol%) of U was calculated. EO The content ratio and U PO The ratio of U to the total content of EO The content (mol %) of was calculated.

[0139] <Method for measuring weight average molecular weight Mw and number average molecular weight Mn> The molecular weight of samples such as polyester A, crystalline polyester, and styrene acrylic is measured by gel permeation chromatography (GPC) as follows.

[0140] First, the sample is dissolved in tetrahydrofuran (THF). In the case of polyester A or styrene acrylic, the sample is dissolved in THF at room temperature for 24 hours. In the case of crystalline polyester, the THF is heated to 40°C to dissolve the sample, and then the sample is left to stand for 24 hours.

[0141] The solution containing each sample was filtered through a solvent-resistant membrane filter "Myshoridisc" (Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. The sample solution was adjusted so that the concentration of components soluble in THF was 0.8% by mass. Measurements were performed using this sample solution under the following conditions. Apparatus: HLC8120GPC (detector: RI) (Tosoh Corporation) Column: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko Co., Ltd.) Eluent: tetrahydrofuran (THF) ·Flow rate: 1.0mL / min Oven temperature: 40.0℃ Sample injection volume: 0.10 mL

[0142] To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using standard polystyrene resins (for example, trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0143] <Method for measuring melting point> The melting points of materials such as crystalline polyester, release agent, and plasticizer are measured using a differential scanning calorimeter (DSC) Q2000 (manufactured by TA Instruments) under the following conditions. Heating rate: 10℃ / min Measurement start temperature: 20℃ Measurement end temperature: 180℃

[0144] The melting points of indium and zinc are used to correct the temperature of the detector, and the heat of fusion of indium is used to correct the amount of heat.

[0145] Specifically, approximately 5 mg of sample is weighed out and placed in an aluminum pan, and a single measurement is performed. An empty aluminum pan is used as a reference. The peak temperature of the maximum endothermic peak at this time is taken as the melting point.

[0146] <Measurement of glass transition temperature Tg> The glass transition temperature (Tg) is measured in accordance with ASTM D3418-82 using a differential scanning calorimeter (Q2000, manufactured by TA Instruments). The melting points of indium and zinc are used for temperature correction of the detector, and the heat of fusion of indium is used for heat correction. Specifically, approximately 2 mg of sample is weighed out and placed in an aluminum pan. An empty aluminum pan is used as a reference. Measurements are performed at a temperature range of -10 to 200°C at a heating rate of 10°C / min. The sample is heated to 200°C, then cooled to -10°C, and then heated again. During this second heating process, the specific heat change is measured in the temperature range of 30°C to 100°C. The glass transition temperature (Tg) is determined as the intersection of the line midway between the baselines before and after the specific heat change and the differential heat curve.

[0147] <Acid value measurement> The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of sample. The acid value in the present disclosure is measured in accordance with JIS K 0070-1992, and specifically, is measured according to the following procedure.

[0148] Titration is performed using a 0.1 mol / L potassium hydroxide ethyl alcohol solution (Kishida Chemical Co., Ltd.). The factor of the potassium hydroxide ethyl alcohol solution can be determined using a potentiometric titrator (Kyoto Electronics Manufacturing Co., Ltd., Potentiometric Titration Measuring Apparatus AT-510). 100 mL of 0.100 mol / L hydrochloric acid is placed in a 250 mL tall beaker and titrated with the potassium hydroxide ethyl alcohol solution, and the factor is determined from the amount of the potassium hydroxide ethyl alcohol solution required for neutralization. The 0.100 mol / L hydrochloric acid used is prepared in accordance with JIS K 8001-1998.

[0149] The conditions for measuring the acid value are shown below. Titrator: Potentiometric titrator AT-510 (Kyoto Electronics Manufacturing Co., Ltd.) Electrode: Composite glass electrode double junction type (Kyoto Electronics Manufacturing Co., Ltd.) Titrator control software: AT-WIN Titration analysis software: Tview The titration parameters and control parameters during titration are as follows: <Titration parameters> Titration mode: Blank titration Titration method: Total volume titration Maximum titer: 20mL Waiting time before titration: 30 seconds Titration direction: automatic <Control parameters> End point judgment potential: 30dE End point potential: 50 dE / dmL End point detection judgment: Not set Control speed mode: Standard Gain: 1 Data collection potential: 4mV Data collection titration volume: 0.1 mL Main test: Accurately weigh 0.100 g of the sample to be measured into a 250 mL tall beaker, add 150 mL of a toluene / ethanol (3:1) mixture, and dissolve over 1 hour. Using the potentiometric titrator described above, titrate with the potassium hydroxide ethyl alcohol solution described above. Blank test: Perform titration in the same manner as above, except that no sample is used (i.e., only a toluene / ethanol (3:1) mixed solution is used). Substitute the obtained results into the following formula to calculate the acid value. A=[(CB)×f×5.611] / S (In the formula, A: acid value (mgKOH / g), B: amount of potassium hydroxide ethyl alcohol solution added for the blank test (mL), C: amount of potassium hydroxide ethyl alcohol solution added for the main test (mL), f: factor of the potassium hydroxide ethyl alcohol solution, and S: sample (g).)

[0150] <Method for measuring the average circularity of toner particles> The average circularity of the toner or toner particles is measured using a flow particle image analyzer, "FPIA-3000" (manufactured by Sysmex Corporation), under the measurement and analysis conditions used during calibration work.

[0151] To 20 mL of ion-exchanged water, an appropriate amount of surfactant and alkylbenzene sulfonate was added as a dispersant, and then 0.02 g of the measurement sample was added and dispersed for 2 minutes using a tabletop ultrasonic cleaner disperser (product name: VS-150, manufactured by Vervoclear Co., Ltd.) with an oscillation frequency of 50 kHz and an electrical output of 150 watts to obtain a dispersion for measurement. At this time, the dispersion was appropriately cooled so that the temperature was between 10°C and 40°C.

[0152] For the measurement, the flow particle image analyzer equipped with a standard objective lens (10x) is used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) is used as the sheath liquid. The dispersion liquid prepared according to the above procedure is introduced into the flow particle image analyzer, and 3,000 toner particles (particles) are measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis is set to 85%, and the analyzed particle diameter is limited to a circle-equivalent diameter of 1.98 μm or more and 19.92 μm or less, and the average circularity of the toner particles (particles) is determined.

[0153] Before starting the measurement, automatic focus adjustment is performed using standard latex particles (for example, 5100A (trade name) manufactured by Duke Scientific diluted with ion-exchanged water). After that, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0154] <Method for measuring weight average particle size (D4) of toner> The weight-average particle size (D4) and number-average particle size (D1) of the toner were measured with an effective number of 25,000 measurement channels using a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube and employing the narrow-pore electrical resistance method, and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data, and were then calculated by analyzing the measurement data.

[0155] The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter).

[0156] Before carrying out the measurements and analysis, the dedicated software was set up as follows.

[0157] In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value obtained using "Standard Particles 10.0 μm" (Beckman Coulter). Press the threshold / noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement."

[0158] In the dedicated software's "Pulse to particle size conversion setting screen," set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range from 2 μm to 60 μm.

[0159] The specific measurement method is as follows. 1. Pour approximately 200 mL of the electrolyte solution into a 250 mL round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture flush" function of the analysis software to remove any dirt and air bubbles from inside the aperture tube. 2. Approximately 30 mL of the above electrolytic solution is placed in a 100 mL flat-bottom glass beaker, and approximately 0.3 mL of a diluted solution prepared by diluting "Contaminon N" (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water is added as a dispersant. 3. A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser, "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.), which has two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees and an electrical output of 120 W, and approximately 2 mL of the above-mentioned Contaminon N is added to this water tank. 4. Place the beaker from step 2 into the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized. 5. While ultrasonic waves are being applied to the electrolyte solution in the beaker from step 4, approximately 10 mg of toner is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion process, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. 6. Using a pipette, add dropwise the aqueous electrolyte solution prepared in step 5, in which the toner has been dispersed, to the round-bottom beaker prepared in step 1, placed inside the sample stand, and adjust the measurement concentration to approximately 5%. Then, measurements are continued until the number of measured particles reaches 50,000. 7. The measurement data is analyzed using the dedicated software provided with the device to calculate the weight average particle size (D4) and number average particle size (D1). Note that when the dedicated software is set to Graph / Number % or Graph / Volume %, the "Arithmetic diameter" on the Analysis / Number Statistics (Arithmetic Mean) and Analysis / Volume Statistics (Arithmetic Mean) screens is the number average particle size (D1) and weight average particle size (D4), respectively.

[0160] <Method for separating titanate particles from the toner surface> A concentrated sucrose solution was prepared by adding 1.6 kg of sucrose (Kishida Chemical) to 1 L of ion-exchanged water and dissolving it in a hot water bath. 31 g of the concentrated sucrose solution and 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a centrifuge tube to prepare a dispersion. 10 g of toner was added to the dispersion, and any clumps of toner were broken up using a spatula or similar tool.

[0161] The centrifuge tube is placed in an Iwaki Sangyo KM Shaker (model V.SX) and shaken at 350 strokes per minute for 20 minutes. After shaking, the solution is transferred to a 50 mL glass tube for a swing-out rotor and centrifuged at 3,500 rpm for 30 minutes.

[0162] After centrifugation, the toner particles are present in the top layer of the glass tube, and the inorganic particle mixture containing titanate particles is present in the lower aqueous solution. The lower aqueous solution is separated and then dried to obtain the inorganic particle mixture. The centrifugation process is repeated until the total amount of the obtained inorganic particle mixture reaches 10 g or more.

[0163] Next, 10 g of the obtained inorganic fine particle mixture is dispersed in a dispersion liquid containing 100 mL of ion-exchanged water and 6 mL of Contaminon N. The obtained dispersion liquid is transferred to a glass tube (50 mL) for a swing rotor and centrifuged in a centrifuge at 3500 rpm for 30 minutes.

[0164] After centrifugation, the bottom layer of the glass tube contains titanate particles, while the top layer, which is the aqueous solution, contains other inorganic particles.

[0165] The mixture of inorganic fine particles containing the titanate fine particles in the bottom layer is collected, and centrifugal separation is repeated as necessary to separate the titanate fine particles sufficiently, followed by drying and collecting the titanate fine particles. This process is repeated until the required amount of titanate fine particles is collected.

[0166] <Method for identifying surface treatment agents for titanate fine particles> 1 mL of chloroform was added to 0.05 g of the obtained titanate microparticles, and the obtained sample solution was treated in an ultrasonic disperser for 10 minutes to extract the surface treatment agent into the chloroform solution.

[0167] Further, the solid content is removed by centrifugation (model: HITACHI himac CR22G, conditions: 12,000 rpm) and filtration. The obtained solution is analyzed by GC-MS (gas chromatography mass spectrometry).

[0168] The specific measurement conditions are as follows. GCMS equipment: Trace1310 (Thermo Fisher Scientific), ISQ (Thermo Fisher Scientific) Column: HP-5ms 30m Inlet temperature: 250℃ Injection volume: 1μL Column oven temperature: 40°C → 300°C (15°C / min) MS ionization mode: EI, ion source temperature: 250°C, mass range: 35-800 m / z

[0169] The profile obtained by the analysis is analyzed, and the peak positions and mass spectrum of the measured sample are confirmed to identify the treating agent present on the surface of the titanate microparticles.

[0170] <Composition analysis of titanate particles> The composition analysis of the titanate fine particles is described below.

[0171] The titanate particles are observed using an SEM and analyzed using an EDX. The following analytical equipment is used. The titanate particles are separated from the toner surface and collected using the method described above. SEM: JEOL, JSM7800 EDX: ThermoFisher Scientific Talos F200X

[0172] Observation was performed at a magnification of 10,000 times, and EDX analysis was performed to confirm that the particles consisted of at least titanium and oxygen. Qualitative analysis was also performed using an X-ray diffractometer (XRD) to confirm that the particles were titanium oxides.

[0173] <Method for measuring the content of titanate fine particles> The content A of the titanate fine particles is determined in mass % by the standard addition method. A specific example will be described below using strontium titanate as the titanate.

[0174] 3 g of toner is placed in an aluminum ring with a diameter of 30 mm and pelletized under a pressure of 10 tons.

[0175] The strontium (Sr) intensity is then determined using wavelength-dispersive X-ray fluorescence analysis (XRF) (Sr intensity-1). While the measurement conditions may be optimized for the XRF device used, the entire series of intensity measurements are performed under the same conditions. Strontium titanate particles are added to the toner particles at 1.0% by mass relative to the toner particles and mixed using a coffee mill. After mixing, the mixture is pelletized in the same manner as above, and the Sr intensity is determined in the same manner (Sr intensity-2). The same procedure is repeated for samples in which strontium titanate particles are added at 2.0% and 3.0% by mass relative to the toner particles, and the Sr intensity is determined (Sr intensity-3, Sr intensity-4). Using Sr intensity-1 to Sr intensity-4, the strontium titanate content (mass%) in the toner is calculated using the standard addition method.

[0176] The content of other titanates can also be determined by a similar method.

[0177] <Method for measuring the dielectric constant of titanate fine particles> To measure the relative permittivity of titanate microparticles, an SI 1260 electrochemical interface (manufactured by Toyo Corporation) was used as the power source and ammeter, and a 1296 dielectric interface (manufactured by Toyo Corporation) was used as the current amplifier. The measurement sample was prepared by heat-molding the sample into a disk shape with a thickness of 3.0 ± 0.5 mm using a tablet press. Circular gold electrodes with a diameter of 10 mm were fabricated on the top and bottom surfaces of the sample using mask deposition. The measurement electrodes were attached to the prepared measurement sample, and an AC voltage with a peak-to-peak voltage (Vp-p) of 100 mV and a frequency of 0.1 MHz was applied to measure the capacitance and impedance.

[0178] The relative permittivity εr and volume resistivity ρv of the measurement sample are calculated using the following formulas. εr=dC / ε0S ρv=ZS / d d: thickness of the measurement sample (m) C: Capacitance (F) ε0: Dielectric constant of vacuum (F / m) S: Electrode area (m 2 ) Z: Impedance (Ω)

[0179] <Method for calculating the number average particle size of primary particles of titanate fine particles> The number-average particle size of primary particles of titanate microparticles is calculated using images obtained by backscattered electron observation with the S-4800. Backscattered electron images show less charge-up of titanate microparticles than secondary electron images, allowing for accurate measurement of particle size.

[0180] (1) Measurement preparation Pour liquid nitrogen into the anti-contamination trap attached to the S-4800 housing until it overflows and leave it for 30 minutes. Start the S-4800's "PC-SEM" and perform flushing (cleaning the FE chip, which is the electron source). Click the accelerating voltage display area on the control panel on the screen and press the [Flushing] button to open the flushing execution dialog. Confirm that the flushing intensity is 2 and execute it. Confirm that the emission current due to flushing is 20-40 μA. Insert the sample holder into the sample chamber of the S-4800 housing. Press [Origin] on the control panel to move the sample holder to the observation position.

[0181] Click the accelerating voltage display to open the HV setting dialog, and set the accelerating voltage to [0.8 kV] and the emission current to [20 μA]. In the [Basic] tab of the operation panel, set the signal selection to [SE], select [Upper (U)] and [+BSE] for the SE detector, and select [LA100] in the selection box to the right of [+BSE] to set the mode for observation using backscattered electron images. Also in the [Basic] tab of the operation panel, set the probe current in the electron optical system condition block to [Normal], the focus mode to [UHR], and the WD to [3.0 mm]. Press the [ON] button in the accelerating voltage display on the control panel to apply the accelerating voltage.

[0182] (2) Focus adjustment Drag within the magnification display area on the control panel to set the magnification to 100,000 (100k). Rotate the focus knob [COARSE] on the operation panel to achieve a certain degree of focus, then adjust the aperture alignment. Click [Align] on the control panel to display the alignment dialog, and select [Beam]. Rotate the STIGMA / ALIGNMENT knobs (X, Y) on the operation panel to move the displayed beam to the center of the concentric circles. Next, select [Aperture] and rotate the STIGMA / ALIGNMENT knobs (X, Y) one by one to stop the image movement or adjust it so that it moves as little as possible. Close the aperture dialog and use autofocus to adjust the focus. Repeat this process two more times to adjust the focus.

[0183] (3) Save image Adjust the brightness in ABC mode, take a photo at a size of 640 x 480 pixels, and save it. Use this image file for the following analysis. Take one photo for each titanate particle, and obtain images of at least 300 particles.

[0184] (4) Calculation of the number-average particle size of primary particles of titanate fine particles The maximum diameter of 300 titanate fine particles is determined, and the number-average particle diameter is obtained by arithmetically averaging the maximum diameters obtained.

[0185] Furthermore, by combining elemental analysis using energy dispersive X-ray analysis (EDS), it is possible to determine whether or not the particles are titanate microparticles. Specifically, the toner is observed using a scanning electron microscope "S-4800" (product name; manufactured by Hitachi) at a magnification of up to 100,000 times. The focus is set on the surface of the toner particles, and the external additive to be identified is observed. EDS analysis of the external additive to be identified can be performed, and the element peaks can be used to determine whether or not it is titanate microparticles.

[0186] <Method for quantifying aluminum element in toner particles> The measurement of fluorescent X-rays for each element conforms to JIS K 0119-1969, and specifically is as follows.

[0187] The measurement equipment used was a wavelength dispersive X-ray fluorescence analyzer "Axios" (manufactured by PANalytical) and the accompanying dedicated software "SuperQ ver.4.0F" (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data. Rh was used as the anode of the X-ray tube, the measurement atmosphere was vacuum, the measurement diameter (collimator mask diameter) was 27 mm, and the measurement time was 10 seconds. Light elements were detected using a proportional counter (PC), and heavy elements were detected using a scintillation counter (SC).

[0188] The measurement sample was prepared by placing approximately 4 g of toner particles in a special aluminum ring for pressing, flattening it, and then pressing it at 20 MPa for 60 seconds using a tablet molding compressor "BRE-32" (manufactured by Maekawa Testing Machinery Manufacturing Co., Ltd.) to form a pellet with a thickness of approximately 2 mm and a diameter of approximately 39 mm.

[0189] Measurements are performed using an acceleration voltage and current of 24 kV and 160 mA for the X-ray generator, and elements are identified based on the peak positions of the obtained X-rays. Their concentrations are calculated from the counting rate (unit: cps), which is the number of X-ray photons per unit time.

[0190] [Configurations included in the embodiments of the present invention] The disclosure of this embodiment includes the following configuration. (Configuration 1) A toner having toner particles containing a binder resin and an external additive, 1) The binder resin contains 50% by mass or more of polyester A, and the polyester A contains an isophthalic acid unit U based on the total units derived from the acid component. iso Contains 90 mol% or more of 2) Titanate fine particles are contained as the external additive. A toner characterized by: (Configuration 2) The polyester A contains units U of an ethylene oxide adduct of bisphenol A. EO and the unit U of the propylene oxide adduct of bisphenol A PO It contains The unit U EO and the unit U PO 2. The toner according to claim 1, wherein the total content of the units derived from the alcohol component is 90 mol % or more. (Configuration 3) The unit U EO The content ratio of the unit U PO The unit U EO 3. The toner according to claim 2, wherein the content of is 15 mol % or more and 40 mol % or less. (Configuration 4) The toner according to any one of Configurations 1 to 3, wherein the number average molecular weight (Mn) and weight average molecular weight (Mw) of the tetrahydrofuran (THF) soluble matter of the polyester A measured by gel permeation chromatography (GPC) satisfy the following requirements: 3000≦Mn≦10000 Mw / Mn≧2.5 (Configuration 5) The toner according to any one of Configurations 1 to 4, wherein the toner particles contain 0.015% by mass or more and 0.150% by mass or less of aluminum element. (Configuration 6) The toner according to any one of Configurations 1 to 5, wherein the binder resin contains a crystalline polyester. (Configuration 7) The toner according to any one of Configurations 1 to 6, wherein the toner has an average circularity of 0.950 or more and 0.980 or less. (Configuration 8) The toner according to any one of Configurations 1 to 7, wherein the titanate fine particles are at least one fine particle selected from the group consisting of strontium titanate fine particles, calcium titanate fine particles, and barium titanate fine particles. (Configuration 9) The toner according to any one of Configurations 1 to 8, wherein the titanate fine particles have a relative dielectric constant of 100 or more and 2,000 or less. (Configuration 10) The toner according to any one of Configurations 1 to 9, wherein the content of the titanate fine particles in the toner is 0.01% by mass or more and 5.00% by mass or less. (Configuration 11) The content of the titanate fine particles per 100 parts by mass of the toner particles is A (parts by mass), and the isophthalic acid unit U is based on the total units derived from the acid component constituting the polyester A. iso 11. The toner according to any one of configurations 1 to 10, wherein when the content ratio of the polyester A contained in the binder resin is B (mol %) and the content ratio of the polyester A contained in the binder resin is C (mass %), A, B, and C satisfy the following formula (1): 1.0×10 -5 ≦A / (B×C)≦1.1×10 -4 (1) (Configuration 12) The toner according to any one of Configurations 1 to 11, wherein the surface of the titanate fine particles is treated with a silane coupling agent or a fatty acid. [Example]

[0191] The present disclosure will be described in more detail below with reference to examples and comparative examples, but is not limited thereto. Parts used in the examples are by weight unless otherwise specified.

[0192] <Production Example 1 of Polyester A> Bisphenol A ethylene oxide 2 mole adduct 27 mol parts Bisphenol A propylene oxide 2 mole adduct 73 moles Isophthalic acid 100 mol parts The above monomers were charged into a flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column, and the temperature was raised to 190°C over 1 hour. It was confirmed that the reaction system was uniformly stirred. 0.9 parts of tin distearate were added to 100 parts of these monomers. The temperature was then raised from 190°C to 250°C over 5 hours while distilling off the generated water, and the dehydration condensation reaction was carried out at 250°C for an additional 2 hours.

[0193] As a result, polyester A-1 was obtained, which had a glass transition temperature of 60.0°C, an acid value of 10 mgKOH / g, a hydroxyl value of 26 mgKOH / g, Mn of 4800, and Mw / Mn of 6.0.

[0194] <Polyester A Production Examples 2 to 13> Polyesters A-2 to A-13 were obtained in the same manner as in Production Example 1 of Polyester A, except that the monomers used in Production Example 1 of Polyester A were changed as shown in Table 1, and the reaction temperature and dehydration condensation time were changed so that the Mn and Mw / Mn of the resulting Polyester A would be the desired values. The results are shown in Table 1.

[0195] In addition, polyesters A-4 and A-5 were produced using bisphenol A ethylene oxide 2-mol adduct (BPA-EO) and bisphenol A propylene oxide 2-mol adduct (BPA-PO) as raw materials, as well as ethylene glycol as the alcohol component in the amounts shown in Table 1.

[0196] [Table 1]

[0197] <Crystalline Polyester Production Example 1> In a reaction vessel equipped with a nitrogen inlet pipe, a dehydration pipe, a stirrer and a thermocouple, 1,10-Decanedicarboxylic acid 100 mol parts 1,9-nonanediol 100 mol parts 0.8 parts of tin dioctylate as a catalyst based on the total mass of the acid alcohol The above materials were placed in a heated and dried two-necked flask, and nitrogen gas was introduced into the vessel to maintain an inert atmosphere while stirring. The mixture was then heated to 170°C for 6 hours with stirring. The mixture was then gradually heated to 230°C under reduced pressure with continued stirring and maintained at this temperature for an additional 3 hours. When the mixture reached a viscous state, it was air-cooled to terminate the reaction, producing Crystalline Polyester 1. The resulting physical properties are shown in Table 2.

[0198] <Crystalline Polyester Production Examples 2 and 3> Crystalline polyesters 2 and 3 were obtained in the same manner as in Crystalline Polyester Production Example 1, except that the alcohol monomers and acid monomers used were changed as shown in Table 2. The physical properties of Crystalline Polyesters 2 and 3 are shown in Table 2.

[0199] [Table 2]

[0200] <Production example of titanate microparticles 1> The hydrous titanium oxide slurry obtained by hydrolysis of an 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 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH to 4.5, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

[0201] To the hydrous titanium oxide, 0.97 times the molar amount of Sr(OH)2·8H2O was added, placed in a SUS reactor, and purged with nitrogen gas. Distilled water was then added to a concentration of 0.5 mol / L in terms of SrTiO3. The slurry was heated to 83°C at a rate of 6.5°C / hour in a nitrogen atmosphere, and allowed to react for 6 hours after reaching 83°C. After the reaction, the slurry was cooled to room temperature, the supernatant liquid was removed, and the mixture was repeatedly washed with pure water.

[0202] The resulting slurry containing the precipitate was adjusted to 40°C, and hydrochloric acid was added to adjust the pH to 2.5. Then, 1.2 parts of stearic acid per 100 parts of solids was added, and the mixture was stirred for 10 hours. A 5 mol / L sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour. The mixture was then filtered and washed, and dried in air at 120°C for 8 hours to obtain titanate microparticles 1. The number-average particle size of the primary particles of the resulting titanate microparticles 1 was 100 nm.

[0203] <Production Example of Titanate Microparticles 2> The hydrous titanium oxide slurry obtained by hydrolysis of an 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 0.5, obtaining a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH to 4.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

[0204] To the titanium oxide hydroxide, 0.93 times the molar amount of Sr(OH)2·8H2O was added, and the mixture was placed in a stainless steel reactor, which was then purged with nitrogen gas. Distilled water was then added to the mixture to a concentration of 0.7 mol / L in terms of SrTiO3.

[0205] The temperature of the slurry was raised to 70° C. at a rate of 8.5° C. / hour in a nitrogen atmosphere, and the reaction was carried out for 5 hours after the temperature reached 70° C. After the reaction, the slurry was cooled to room temperature, the supernatant liquid was removed, and the mixture was repeatedly washed with pure water.

[0206] The resulting slurry containing the precipitate was adjusted to 40°C, and hydrochloric acid was added to adjust the pH to 2.5. Then, 1.2 parts of stearic acid per 100 parts of solids was added, and the mixture was stirred for 10 hours. A 5 mol / L sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour. The mixture was then filtered and washed, and dried in air at 120°C for 8 hours to obtain titanate microparticles 2. The number-average particle size of the primary particles of the resulting titanate microparticles 2 was 30 nm.

[0207] <Production Example of Titanate Microparticles 3> 600 g of strontium carbonate and 320 g of titanium oxide were wet mixed in a ball mill for 8 hours, filtered, and then dried. This mixture was subjected to a pressure of 0.49 MPa (5 kg / cm 2 The mixture was molded under a pressure of 1000 kJ / cm2, calcined at 1100°C for 8 hours, and mechanically pulverized to obtain strontium titanate particles. 100 parts of pure water was added to 100 parts of the obtained particles and stirred to form a slurry. Hydrochloric acid was added to this slurry to adjust the pH to 2.5, and the temperature was then adjusted to 40°C. 1.2 parts of stearic acid per 100 parts of solids was added and stirred for 10 hours. 5 mol / L sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour. The mixture was then filtered, washed, and dried in air at 120°C for 8 hours to obtain titanate microparticles 3. The number-average particle size of the primary particles of the obtained titanate microparticles 3 was 300 nm.

[0208] <Production Example of Titanate Microparticles 4> Titanate microparticles 4 were obtained in the same production method as titanate microparticles 1, except that lauric acid was used instead of stearic acid used in the production example of titanate microparticles 1. The number average particle size of the primary particles of the obtained titanate microparticles 4 was 100 nm.

[0209] <Production Example of Titanate Microparticles 5> Titanate microparticles 5 were obtained in the same production method as titanate microparticles 1, except that montanic acid was used instead of stearic acid used in the production example of titanate microparticles 1. The number average particle size of the primary particles of the obtained titanate microparticles 5 was 100 nm.

[0210] <Production Example of Titanate Microparticles 6> Titanate microparticles 6 were obtained in the same manner as titanate microparticles 1, except that the treatment with stearic acid carried out in the production example of titanate microparticles 1 was not carried out. The number average particle size of the primary particles of the obtained titanate microparticles 6 was 100 nm.

[0211] <Production Example of Titanate Microparticles 7> Metatitanic acid obtained by the sulfuric acid method was deironized and bleached, then added with aqueous sodium hydroxide to adjust the pH to 9.0, desulfurized, and then neutralized with hydrochloric acid to pH 5.8, filtered, and washed with water. Water was added to the washed cake to make a slurry of 1.85 mol / L in terms of TiO2, and hydrochloric acid was added to adjust the pH to 1.0, followed by deflocculation.

[0212] After desulfurization and peptization, 1.88 moles of TiO2 was collected and placed in a 3-liter reaction vessel. 2.16 moles of calcium chloride aqueous solution was added to the peptized metatitanic acid slurry to achieve a Ca / Ti (molar ratio) of 1.15, and the TiO2 concentration was adjusted to 0.5 moles / liter. The mixture was then heated to 90°C with stirring, and 440 mL of 10 moles / liter sodium hydroxide aqueous solution was added over 45 minutes. The reaction was then completed by continuing stirring at 95°C for 1 hour.

[0213] The reaction slurry was cooled to 50°C, and hydrochloric acid was added until the pH reached 5.0, followed by stirring for 20 minutes. The resulting precipitate was washed by decantation, filtered, and then dried in air at 120°C for 8 hours. 300 g of the dried product was then placed in a dry particle compositer (Hosokawa Micron Nobilta NOB-130). The mixture was treated at 30°C for 10 minutes with a rotary blade moving at 90 m / sec.

[0214] Hydrochloric acid was then added to the dried product until the pH reached 0.1, and stirring was continued for 1 hour. The resulting precipitate was decanted and washed. The slurry containing the resulting precipitate was adjusted to 40°C, and hydrochloric acid was added to adjust the pH to 2.5. 1.2 parts of stearic acid per 100 parts of solids was then added, and stirring was continued for 10 hours. 5 mol / L sodium hydroxide solution was added to adjust the pH to 6.5, and stirring was continued for 1 hour. The resulting product was then filtered and washed, and dried in air at 120°C for 8 hours to obtain titanate microparticles 7. The number-average particle size of the primary particles of the resulting titanate microparticles 7 was 100 nm.

[0215] <Production Example of Titanate Microparticles 8> Titanate microparticles 8 were obtained by the same production method as titanate microparticles 7, except that barium chloride was used instead of calcium chloride used in the production example of titanate microparticles 7. The number average particle size of the primary particles of the obtained titanate microparticles 8 was 100 nm.

[0216] <Production Example of Titanate Microparticles 9> Titanate microparticles 9 were obtained in the same production method as titanate microparticles 7, except that potassium chloride was used instead of calcium chloride used in the production example of titanate microparticles 7. The number average particle size of the primary particles of the obtained titanate microparticles 9 was 100 nm.

[0217] <Production Example of Titanate Microparticles 10> Titanate microparticles 10 were obtained in the same production method as titanate microparticles 1, except that n-octylethoxysilane was used instead of stearic acid used in the production example of titanate microparticles 1. The number average particle size of the primary particles of the obtained titanate microparticles 10 was 100 nm.

[0218] <Production Example of Titanate Microparticles 11> The hydrous titanium oxide slurry obtained by hydrolysis of an 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 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH to 4.5, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

[0219] To the hydrous titanium oxide, 0.97 times the molar amount of Sr(OH)2·8H2O was added, placed in a SUS reactor, and purged with nitrogen gas. Distilled water was then added to a concentration of 0.5 mol / L in terms of SrTiO3. The slurry was heated to 83°C at a rate of 6.5°C / hour in a nitrogen atmosphere, and allowed to react for 6 hours after reaching 83°C. After the reaction, the slurry was cooled to room temperature, the supernatant liquid was removed, and the mixture was repeatedly washed with pure water.

[0220] To 100 parts of the solids content of the resulting slurry containing the precipitate, 0.7 parts of silicone oil emulsion (dimethylpolysiloxane emulsion) "SM7036EX" (manufactured by Toray Dow Corning Silicone Co., Ltd.) was added and stirred for 30 minutes, thereby subjecting the strontium titanate particles to a wet hydrophobic treatment. Subsequently, a 4.0 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 6.5, and the particles were filtered, washed, and then dried at 120°C for 8 hours to obtain titanate microparticles 11. The number-average particle size of the primary particles of the resulting titanate microparticles 11 was 100 nm.

[0221] The dielectric constant of the obtained titanate microparticles 1 to 11 was measured by the method described in the above <Method for measuring the dielectric constant of titanate microparticles>. The results are shown in Table 3.

[0222] [Table 3]

[0223] <Preparation of Resin Particle Dispersion of Polyester A-1> Polyester A-1 100 parts 50 parts methyl ethyl ketone 20 parts isopropyl alcohol The above-mentioned methyl ethyl ketone and isopropyl alcohol were added to a container. Then, the above-mentioned polyester A-1 was gradually added and stirred until completely dissolved, yielding a polyester A-1 solution. The container containing this polyester A-1 solution was set to 65°C, and while stirring, a 10% aqueous ammonia solution was gradually added dropwise to a total of 5 parts, followed by 230 parts of ion-exchanged water at a rate of 10 mL / min to induce phase inversion emulsification. The pressure was then reduced in an evaporator to remove the solvent, yielding a resin particle dispersion of polyester A-1. The volume average particle size of the resin particles contained in this resin particle dispersion was 130 nm. The solid content was adjusted to 20% with ion-exchanged water.

[0224] <Preparation of Resin Particle Dispersion of Crystalline Polyester 1> 100 parts crystalline polyester 50 parts methyl ethyl ketone 20 parts isopropyl alcohol The methyl ethyl ketone and isopropyl alcohol were added to a container. The crystalline polyester 1 was then gradually added and stirred until completely dissolved, yielding a crystalline polyester 1 solution. The container containing the crystalline polyester 1 solution was set to 40°C, and while stirring, a 10% aqueous ammonia solution was gradually added dropwise to a total of 3.5 parts, followed by 230 parts of ion-exchanged water at a rate of 10 mL / min to induce phase inversion emulsification. The pressure was then reduced to remove the solvent, yielding a resin particle dispersion of crystalline polyester 1. The volume average particle size of the resin particles in this resin particle dispersion was 150 nm. The solid content was adjusted to 20% with ion-exchanged water.

[0225] <Preparation of Colorant Particle Dispersion> Copper phthalocyanine (pigment blue 15:3) 45 parts 5 parts of ionic surfactant Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 190 parts ion-exchanged water The above components were mixed and dispersed for 10 minutes using a homogenizer (Ultra Turrax manufactured by IKA Corporation), followed by a dispersion treatment for 20 minutes at a pressure of 250 MPa using an Ultimizer (a counter-impact wet grinder manufactured by Sugino Machine Corporation), to obtain a colorant particle dispersion liquid having a volume average particle size of 120 nm and a solid content of 20%.

[0226] <Preparation of Release Agent Particle Dispersion> Release agent (hydrocarbon wax, melting point: 79°C) 15 parts 2 parts of ionic surfactant Neogen RK (Dai-ichi Kogyo Seiyaku Co., Ltd.) 240 parts ion-exchanged water The above was heated to 100°C and thoroughly dispersed using an Ultra Turrax T50 manufactured by IKA. Next, the mixture was heated to 115°C using a pressure discharge Gaulin homogenizer and dispersed for 1 hour, to obtain a release agent particle dispersion liquid with a volume average particle size of 160 nm and a solid content of 20%.

[0227] <Production Example of Toner Particle 1> 900 parts of polyester A-1 resin particle dispersion 100 parts of crystalline polyester resin particle dispersion Colorant particle dispersion 50 parts 80 parts of release agent particle dispersion First, the above materials were placed in a round stainless steel flask and mixed. Then, the mixture was dispersed for 10 minutes at 5000 rpm using an Ultra Turrax T50 homogenizer (manufactured by IKA). After adjusting the pH to 8.0 with a 1 mol / L aqueous solution of sodium hydroxide, an aqueous solution of 0.50 parts of aluminum chloride dissolved in 20 parts of ion-exchanged water was added as a flocculant at 30°C over 10 minutes with stirring. After leaving the mixture for 3 minutes, the temperature was raised to 50°C to generate flocculated particles.

[0228] The volume average particle size of the formed aggregated particles was appropriately confirmed using a Coulter Multisizer III, and the aggregation step was terminated when aggregated particles having a size of 6.0 μm were formed.

[0229] Thereafter, as a spheronization step, a 1 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 9.0, and the mixture was heated to 92°C while continuing to stir.

[0230] Once the desired surface shape was obtained, heating was stopped, and as a cooling step, ice was quickly added to cool the sample to 40°C at a cooling rate of 10°C / s or more, and then an annealing step was performed at 55°C for 3 hours.

[0231] The mixture was then cooled to 25°C, filtered, and subjected to solid-liquid separation, followed by washing with ion-exchanged water. After washing, the mixture was dried in a vacuum dryer to obtain toner particles 1 having a weight-average particle size (D4) of 7.1 μm. The formulation and physical properties of toner particles 1 are shown in Table 4.

[0232] <Production Examples of Toner Particles 2 to 23 and 25 to 44> Toner particles 2 to 23 and 25 to 44 were obtained in the same manner as in the production example of toner particle 1, except that the blending of materials used and production conditions were changed so as to obtain the formulation and physical properties shown in Table 4.

[0233] <Production Example of Toner Particles 24> (Production of toner particles by pulverization method) The following materials were thoroughly mixed in an FM mixer (manufactured by Nippon Coke and Engineering Co., Ltd.), and then melt-kneaded in a twin-screw kneader (manufactured by Ikegai Iron Works Co., Ltd.) set at a temperature of 100°C. Polyester A-1 90.0 parts Crystalline polyester 1 10.0 parts Hydrocarbon wax (melting point: 79°C) 8.0 parts ·CIPigment Blue15:3 5.0 copies

[0234] The obtained kneaded product was cooled and coarsely crushed to 1 mm or less using a hammer mill to obtain a coarsely crushed product.

[0235] Next, the obtained coarsely crushed material was pulverized using a turbo mill manufactured by Turbo Kogyo Co., Ltd. to obtain finely crushed material of approximately 6.5 μm, and then a multi-division classifier utilizing the Coanda effect was used to remove fine and coarse particles to obtain toner particles 24.

[0236] The weight average particle size (D4) of the toner particles 24 was 7.1 μm, Tg was 58.4° C., and the average circularity was 0.945. The formulation and physical properties of the toner particles 24 are shown in Table 4.

[0237] <Toner 1 manufacturing example> External addition was performed on the above toner particles 1. Using an FM mixer (FM10 manufactured by Nippon Coke & Engineering Co., Ltd.), 6.0 g of titanate microparticles 1 (0.3 parts per 100 parts of toner particles) and 20 g of hydrophobic silica microparticles (primary particle number average particle size: 7 nm) surface-treated with dimethyl silicone oil (1.0 part per 100 parts of toner particles) were added to 2.0 kg of toner particles 1, and then the mixture was mixed at 3000 rpm for 5 minutes. During this process, the temperature inside the tank was adjusted to 35°C after 5 minutes of mixing by controlling the flow and temperature of cold water flowing through the cooling jacket. The physical properties of the resulting toner 1 are shown in Table 4.

[0238] <Production examples of toners 2 to 44> Toners 2 to 44 were obtained in the same manner as in Production Example of Toner 1, except that in Production Example of Toner 1, the type of toner particles and the type and content of titanate fine particles were changed as shown in Table 4. The physical properties of the obtained Toners 2 to 44 are shown in Table 4.

[0239] [Table 4]

[0240] [Examples 1 to 40, Comparative Examples 1 to 4] As the image forming apparatus for evaluating the performance of each toner, a color laser printer, HP LaserJet Enterprise Color M555dn (manufactured by HP), equipped with a one-component toner contact development blade cleaning system, and its consumable cartridge, a modified HP212X black toner cartridge (W2120X) CRG, were used.

[0241] The main body was modified so that the process speed was set to 150% and printing tests could be performed using only the black station. The cartridge was also modified to increase the volume of the toner container so that the following toner loading amount could be accommodated, and the following evaluations 1 to 4 were carried out. This enabled a longer lifespan durability evaluation to be performed on a main body that runs faster than before. The evaluation results are shown in Table 5.

[0242] <Evaluation 1. Set-through of solid images under normal temperature and humidity conditions> To evaluate the fixing quality of the fixed image, the offset of a solid image was evaluated in a normal temperature and humidity environment (temperature 25°C, relative humidity 55%). The printer body and a toner cartridge filled with 550 g of the toner of the example were left in a 25°C, 55% RH environment for 24 hours in order to adjust the temperature and humidity in the evaluation environment. After that, in the same environment, a letter-size XEROX 4200 paper (manufactured by XEROX Corporation, basis weight 75 g / m) was printed. 2 ) solid (toner amount: 0.6mg / cm 2 50 sheets of paper with the image formed thereon were printed out on one side, and the sheets with the image formed thereon were stacked so that the blank side without the image was on top of the image formed side.

[0243] Next, the stacked sheets were turned over, and a line was drawn on the blank side, where no image was formed, using a 2H pencil at an angle of 45°±1° with a load of 1 kg (9.8 N). The paper underneath the pencil-drawn sheet was then evaluated for offset according to the following criteria. A grade of C or higher was considered good. (Evaluation criteria) A: There is no visible bleed-through at all on the white paper. B: A few small black spots are visible on the white paper. C: A slight linear black stain is visible on the white paper. D: Slight bleeding along the pencil lines onto the white paper is visible. E: Pencil lines are clearly visible on the white paper.

[0244] <Evaluation 2. Low-temperature fixability of halftone images in a low-temperature, low-humidity environment (decrease in density due to rubbing)> The test was carried out in a low-temperature, low-humidity environment (temperature 15°C, relative humidity 10%), which is a severe environment for evaluating low-temperature fixability. The printer body and a toner cartridge filled with 550 g of the toner of the example were left in an environment of 15°C and 10% RH for 24 hours in order to control the temperature and humidity in the evaluation environment. The paper used for evaluation was COTTON BOND LIGHT COCKLE (basis weight 90 g / m), which is rough paper that is prone to be disadvantageous in low-temperature fixability due to its unevenness. 2 ) was used.

[0245] The evaluation procedure was as follows: the entire fixing unit was at room temperature, and the density of the halftone image was adjusted so that the image density (measured using a portable spectrophotometer Exact Advance (manufactured by X-Rite)) was 0.75 to 0.80 at a set temperature of 170°C, and 10 images were printed.

[0246] The image was then output at a set temperature of 150°C, and the fixed image was rubbed 10 times with Silbon paper under a load of 5.4 kPa. The density reduction rate at 150°C was calculated using the following formula from the image density before and after rubbing. Density reduction rate (%) = (image density before rubbing - image density after rubbing) / image density before rubbing × 100

[0247] Similarly, the fixing temperature was increased by 5°C increments up to 200°C, and the density reduction rate was calculated.

[0248] From the evaluation results of the fixing temperature and density drop rate obtained through a series of operations, a quadratic polynomial approximation was performed to obtain a relational expression between the fixing temperature and density drop rate. Using this relational expression, the temperature at which the density drop rate becomes 15% was calculated, and this temperature was set as the fixing temperature that indicates the threshold value for good low-temperature fixability. The lower the fixing temperature, the better the low-temperature fixability, and in the present disclosure, a grade of C or higher is an acceptable level. (Evaluation criteria) A. The fixing temperature is less than 180°C. B. The fixing temperature is 180°C or higher and lower than 190°C. C. The fixing temperature is 190°C or higher and lower than 200°C. D. The fixing temperature is 200°C or higher.

[0249] <Evaluation 3. Transfer efficiency evaluation of solid images under low temperature and low humidity conditions> To evaluate transferability, transfer efficiency was evaluated in a low-temperature, low-humidity environment (15°C temperature, 10% relative humidity). The printer and a toner cartridge filled with 550 g of the example toner were left in a 15°C, 10% RH environment for 24 hours to control the temperature and humidity in the evaluation environment. After that, 50 solid images were printed under the same environment, and then another solid image was printed. Once the toner was transferred to the intermediate transfer belt, the development process was forcibly stopped. The toner transferred to the intermediate transfer belt and the toner remaining on the photosensitive drum after transfer were then peeled off with transparent polyester adhesive tape. The density difference was calculated by subtracting the toner density of the paper with only the adhesive tape attached from the density of the paper with the peeled adhesive tape attached.

[0250] Transfer efficiency is the ratio of the difference in toner concentration on the intermediate transfer belt when the sum of the differences in toner concentration is 100; the higher this ratio, the better the transfer efficiency. The transfer efficiency after output was evaluated according to the following evaluation criteria. The toner concentration was measured using a "504 Spectrodensitometer" (manufactured by X-Rite).

[0251] The evaluation criteria are as follows: (Evaluation criteria) A: Transfer efficiency is 99% or more B: Transfer efficiency is 97% or more but less than 99% C: Transfer efficiency is 95% or more but less than 97% D: Transfer efficiency is less than 95%

[0252] Evaluation 4: Transferability evaluation after endurance use in a low-temperature, low-humidity environment (voids in vertical thin line images) To evaluate transferability, we evaluated the occurrence of voids in vertical thin line images in a low-temperature, low-humidity environment (15°C temperature, 10% relative humidity). The printer body and a toner cartridge filled with 550 g of the example toner were left in a 15°C, 10% RH environment for 24 hours to control the temperature and humidity in the evaluation environment. After printing 20,000 images with a 1.0% print ratio under the same environment, we similarly printed evaluation images with two vertical lines of 2, 4, 6, 8, and 10 dots each, with the non-latent image area between each line approximately 10 mm wide. The printed evaluation images were observed visually and with a 20x magnification loupe and evaluated based on the following criteria. (Evaluation criteria) A: In the two-dot line, almost no hollows can be seen even under magnification. B: In the 2-dot line, a small amount of void was observed under magnification, and in the 4-dot line, almost no void was observed under magnification. C: In the 4-dot line, a small amount of void was observed under magnification, but in the 2-dot line, no void was visible to the naked eye. D: Holes can be visually confirmed in the 2-dot line, but no holes can be visually confirmed in the 4-dot line. E: Hollow areas can be visually confirmed in the 4-dot line.

[0253] [Table 5]

Claims

1. A toner having toner particles containing a binder resin and an external additive, 1) The binder resin contains 50% by mass or more of polyester A, and the polyester A contains an isophthalic acid unit U based on the total units derived from the acid component. iso Contains 90 mol% or more of 2) Titanate fine particles are contained as the external additive. A toner characterized by:

2. The polyester A contains a unit U of an ethylene oxide adduct of bisphenol A. EO and bisphenol A propylene oxide adduct unit U PO It contains The unit U EO and the unit U PO 2. The toner according to claim 1, wherein the total content of the units derived from the alcohol component is 90 mol % or more.

3. The unit U EO The content ratio of the unit U PO The unit U EO 3. The toner according to claim 2, wherein the content of is 15 mol % or more and 40 mol % or less.

4. 3. The toner according to claim 1, wherein the number average molecular weight (Mn) and weight average molecular weight (Mw) of the tetrahydrofuran (THF) soluble matter of the polyester A measured by gel permeation chromatography (GPC) satisfy the following conditions: 3000≦Mn≦10000 Mw / Mn≧2.5

5. 3. The toner according to claim 1, wherein the toner particles contain aluminum in an amount of 0.015% by mass or more and 0.150% by mass or less.

6. 3. The toner according to claim 1, wherein the binder resin contains a crystalline polyester.

7. 3. The toner according to claim 1, wherein the average circularity of the toner is 0.950 or more and 0.980 or less.

8. 3. The toner according to claim 1, wherein the titanate fine particles are at least one fine particle selected from the group consisting of strontium titanate fine particles, calcium titanate fine particles, and barium titanate fine particles.

9. 3. The toner according to claim 1, wherein the titanate fine particles have a relative dielectric constant of 100 or more and 2,000 or less.

10. 3. The toner according to claim 1, wherein the content of the titanate fine particles in the toner is 0.01% by mass or more and 5.00% by mass or less.

11. The content of the titanate fine particles per 100 parts by mass of the toner particles is A (parts by mass), and based on all units derived from the acid component constituting the polyester A, the isophthalic acid unit U iso 3. The toner according to claim 1, wherein when a content ratio of the polyester A contained in the binder resin is B (mol %) and a content ratio of the polyester A contained in the binder resin is C (mass %), A, B, and C satisfy the following formula (1): 1.0×10 -5 ≦A / (B×C)≦1.1×10 -4 (1)

12. 3. The toner according to claim 1, wherein the surface of said titanate fine particles is treated with a silane coupling agent or a fatty acid.

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