Developing device, image forming method, process cartridge and electrophotographic image forming apparatus

Abstract

To provide an image forming apparatus capable of suppressing the occurrence of white spots and achieving low-temperature fixability at the same time. [Solution] A developing device having a developer and a developer carrier for carrying the developer, wherein the developer contains a toner having toner particles containing a binder resin, the toner particles having a core-shell structure with a core containing an ester compound and a shell formed on the surface of the core, the ester compound and the shell containing a compound having a specific structure, and the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate, and the resin layer contains carbon black that meets specified requirements.

Description

[Technical Field]

[0001] The present disclosure relates to a developing device, an image forming method, a process cartridge, and an electrophotographic image forming apparatus. [Background technology]

[0002] Many electrophotographic methods have been known. Generally, a photoconductive material is used to form an electric latent image on an electrostatic latent image carrier (photoreceptor) by various means, and the latent image is then developed with a developer (e.g., toner) to become a visible image. If necessary, the toner image is then transferred to a transfer material such as paper, and then fixed on the transfer material by heat, pressure, or the like to obtain a copy.

[0003] In recent years, there has been a demand for further reductions in power consumption and longer life for electrophotographic image forming devices such as multifunction peripherals and printers. From the perspective of reducing power consumption, there is a particularly growing need for so-called low-temperature fixing toners, which can be fixed with less heat. To meet this demand, ester compounds that help fix toners to paper have been actively investigated. Ester compounds can be broadly divided into two types: those that act as plasticizers to help plasticize the binder resin of the toner, and those that act as release agents, allowing the toner to separate from the fixing device and transfer to paper. Both contribute significantly to low-temperature fixing properties.

[0004] For example, Patent Document 1 discloses a toner containing an ester compound as a release agent in a toner containing a compound having a structure represented by the following formula (8) whose shell can positively charge the toner surface. In Patent Document 1, the use of the ester compound maintains storage stability while enabling improvement in low-temperature fixability in an image forming apparatus using a positively charged toner.

[0005] Furthermore, from the viewpoint of extending life, there is a growing need for a developer carrier (e.g., a developing roller) that boasts high developing performance with little variation in the amount of toner supplied to the photoreceptor even after long-term use. As a means of meeting such demands, various studies are being conducted on developing rollers that incorporate conductive fine particles into the resin layer of the developing roller to control the volume resistivity of the developing roller and stabilize the developing performance. For example, Patent Document 2 discloses a developing roller that uses carbon black as conductive fine particles, which prevents toner from charging up and adhering to the developing roller, thereby preventing a decrease in developing performance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-109538 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-55072 Summary of the Invention [Problem to be solved by the invention]

[0007] However, according to the investigations of the present inventors, when a toner as disclosed in Patent Document 1, in which the shell contains a compound having a structure represented by the following formula (8) and also contains an ester compound, is used to form an image for a long period of time with a developing roller as disclosed in Patent Document 2, in which carbon black is contained in the resin layer, it has become clear that the toner is not sufficiently supplied to the photoreceptor, and the developability is reduced, resulting in the occurrence of white spots in which part of a halftone or solid black image is missing. It was.

[0008] The present disclosure provides an image forming apparatus that can suppress the occurrence of white spots and achieve excellent low-temperature fixability at the same time. [Means for solving the problem]

[0009] The present disclosure provides a developing device having a developer and a developer carrier for carrying the developer, the developer includes a toner having toner particles containing a binder resin; the toner particles have a core-shell structure having a core containing an ester compound and a shell formed on the surface of the core, The ester compound contains at least one ester compound selected from the group represented by the following formulas (1) to (7): The shell contains a compound having a structure represented by the following formula (8): the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate, the resin layer contains carbon black, the arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is 80.0 nm or less; the arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer is 60.0 to 170.0 nm; The present invention relates to a developing device characterized by the above. [ka] In formulas (1) to (8), each independently represents R 1 , R 2 , R 9 , R 10 The carbon number is 16 to 22. Chain alkyl group, R 3 , R 5 , R 6 , R 8 , R 11 , R 12 is a linear alkyl group having 14 to 22 carbon atoms, R 4 , R 7 is a linear alkylene group having 1 to 6 carbon atoms, R 14 represents a linear alkyl group having 1 to 3 carbon atoms.

[0010] The present disclosure provides an image forming method, comprising: a developing step of developing the electrostatic latent image on the image carrier with toner using the developing device; a transfer step of transferring the image developed in the development step to a transfer-receiving material with or without an intermediate transfer body; and a fixing step of fixing the image transferred onto the transfer material; The present invention relates to an image forming method having the following features.

[0011] The present disclosure relates to a process cartridge configured to be detachably attached to a main body of an electrophotographic image forming apparatus, The present invention relates to a process cartridge comprising the above-mentioned developing device.

[0012] The present disclosure relates to an electrophotographic image forming apparatus, The present invention relates to an electrophotographic image forming apparatus comprising the above-mentioned developing device. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a developing device that is free from white spots in images even after long-term printing and that can achieve excellent low-temperature fixability. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic cross-sectional view showing an example of a developing roller. [Figure 2] FIG. 10 is a schematic cross-sectional view showing another example of the developing roller. [Figure 3] FIG. 2 is a schematic diagram of a process cartridge. [Figure 4] FIG. 1 is a schematic diagram of an electrophotographic image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0015] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ.

[0016] The terms "monomer unit" and "monomer subunit" refer to the reacted form of a monomer substance in a polymer. For example, one section of carbon-carbon bond in the main chain of a polymer formed by polymerizing a vinyl monomer is considered to be one unit. A vinyl monomer can be represented by the following formula (A): [ka]

[0017] In formula (A), R A represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) and more preferably a methyl group), and R B represents an optional substituent. In addition, in the present disclosure, a crystalline resin refers to a resin that shows a clear endothermic peak in differential scanning calorimetry (DSC) measurement.

[0018] A developing device according to the present disclosure includes a developer and a developer carrier for carrying the developer, the developer includes a toner having toner particles containing a binder resin; the toner particles have a core-shell structure having a core containing an ester compound and a shell formed on the surface of the core, The ester compound contains at least one ester compound selected from the group represented by the following formulas (1) to (7): The shell contains a compound having a structure represented by the following formula (8): the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate, the resin layer contains carbon black, the arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is 80.0 nm or less; the arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer is 60.0 to 170.0 nm; The developing device is characterized by the above. [ka] In formulas (1) to (8), each independently represents R 1 , R 2 , R 9 , R 10 is a linear alkyl group having 16 to 22 carbon atoms, R 3 , R 5 , R 6 , R 8 , R 11 , R 12 is a linear alkyl group having 14 to 22 carbon atoms, R 4 , R 7 is a linear alkylene group having 1 to 6 carbon atoms, R 14 is a straight chain alkyl chain with 1 to 3 carbon atoms. represents an alkyl group.

[0019] The developing device described above can achieve both no white spots in images even after long-term printing and a high level of low-temperature fixability. The present inventors believe that the mechanism by which these effects are achieved is as follows.

[0020] In a toner having a shell containing a compound having a structure represented by formula (8) and an ester compound, as disclosed in Patent Document 1, the ester group of the ester compound is similar to the structure represented by formula (8), and they easily interact with each other in the toner. As a result, the area where the interaction of the shell containing the compound having the structure represented by formula (8) occurs becomes partially soft. When this soft shell portion is positioned on, or comes into contact with, the resin layer of the developer carrier, the contact area increases because they are both soft, increasing the adhesive force between the toner and the developer carrier and making it difficult for the toner to be developed onto the photoconductor. Hereinafter, a case where the developer carrier is a developing roller will be described as an example, but the developer carrier according to the present disclosure is not limited to this.

[0021] In particular, when printing for a long period of time, the toner undergoes stress due to the friction between the developing roller and the developing blade, causing the toner to change shape and become difficult to roll on the developing roller. This increases the chances of the partially soft shell coming into contact with the resin layer of the developing roller, resulting in a significant decrease in development ability. As described above, it is thought that white spots appear in halftone and solid black images after a long period of printing due to a lack of toner supply caused by a decrease in development ability.

[0022] When the arithmetic mean value Rc of the equivalent circle diameter of carbon black in the resin layer on the outer surface of the substrate of the developing roller is 80.0 nm or less and the arithmetic mean value d of the wall-to-wall distance is 60.0 to 170.0 nm, a developing roller in which carbon black is highly dispersed at appropriate intervals in the resin layer can be obtained, compared to the developing roller disclosed in Patent Document 2. When such a developing roller is used, the soft shell portion of the toner has more opportunities to come into contact with the carbon black in the resin layer of the developing roller. Because the carbon black is harder than the resin layer of the developing roller, even when it comes into contact with the soft shell portion of the toner, an increase in surface area, i.e., an increase in adhesive force, is suppressed. Furthermore, a developing roller with highly dispersed carbon black has a more uniform surface hardness, and even if the toner deforms during long-term printing, it rolls well on the developing roller, maintaining high developability.

[0023] From the above, even when a toner having an ester compound and a shell containing a compound having a structure represented by formula (8) as disclosed in Patent Document 1 is combined with a developing roller containing carbon black in a resin layer, by using the configuration disclosed herein, it is believed that it is possible to provide a developing device capable of low-temperature fixing that suppresses white voids in halftone and solid black images due to insufficient toner supply, even after long-term printing. The present disclosure will be described in detail below.

[0024] <Developer> The developer according to this embodiment contains a toner having toner particles containing a binder resin. Examples of binder resins include polyester resins, vinyl resins, and other binder resins such as the following resins or polymers: styrene-acrylic resins, polyester resins, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and mixed or composite resins thereof.

[0025] The binder resin is preferably at least one selected from the group consisting of polyester resin, styrene-acrylic resin, and hybrid resins thereof, and more preferably styrene-acrylic resin, because it is inexpensive, easily available, and has excellent low-temperature fixing properties. The toner includes toner particles having a core-shell structure having a core containing an ester compound and a shell formed on the surface of the core. By using a toner having toner particles with a core-shell structure, the shell can suppress the leaching of the ester compound, and high developability and storage stability can be achieved at the same time.

[0026] Toner particles having a core-shell structure can achieve a balance between lowering the fixing temperature and preventing aggregation during storage by coating a core layer made of a material with a low softening point with a material with a higher softening point.

[0027] The method for producing toner particles having a core-shell structure is not particularly limited, and they can be produced by any conventionally known method. Among them, the in situ polymerization method and the phase separation method are preferred from the viewpoint of production efficiency. The method for producing core-shell type polymer particles by in situ polymerization will be described below.

[0028] Toner particles having a core-shell structure can be obtained by adding a polymerizable monomer for forming the shell layer (polymerizable monomer for shell) and a polymerization initiator to an aqueous medium in which polymer particles constituting the core layer are dispersed, and polymerizing them.

[0029] Examples of polymerization initiators used in the polymerization of the shell polymerizable monomer include water-soluble polymerization initiators such as metal persulfates, such as potassium persulfate and ammonium persulfate; and azo initiators, such as 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), 2,2'-azobis-(2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine], and hydrates thereof. These can be used alone or in combination of two or more. The amount of polymerization initiator is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the shell polymerizable monomer.

[0030] When the phase separation method is used, it is preferable to add a polymer obtained by prepolymerizing a substance that forms the shell to the polymerizable monomer that forms the core. When a prepolymerized polymer is used, it is more preferable that the prepolymer is a reactive polymer having an unsaturated bond.

[0031] The polymerization temperature for the shell layer is preferably 50° C. or higher, more preferably 60 to 95° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

[0032] The ester compound contained in the core of the toner particle includes at least one ester compound selected from the group represented by formulas (1) to (7). The ester compounds represented by the formulas (1) to (7) effectively act as plasticizers or release agents, enabling fixing at lower temperatures.

[0033] In the ester compounds represented by formulas (1) to (7), R 1 , R 2 , R 9 , R 10 is a linear alkyl group having 16 to 22 carbon atoms (preferably 20 to 22), R 3 , R 5 , R 6 , R 8 , R 11 , R 12 is a linear alkyl group having 14 to 22 carbon atoms (preferably 18 to 22), R 4 , R 7 is a linear alkylene group having 1 to 6 carbon atoms (preferably 2 to 4). 1 ~R 12 are each independent and may be different from each other. Ester compounds having an R moiety within the above range can be easily produced or obtained by known means. Furthermore, when an ester compound having a large number of carbon atoms in the alkyl group is used, the bond due to interaction with the shell containing the compound having the structure represented by formula (8) is weakened, and deterioration of developability and storage stability can be suppressed.

[0034] When a cross section of the toner is observed with a scanning transmission electron microscope (STEM), the number average major axis of the ester compound is preferably 300 nm or less. The number-average major axis of the ester compound being 300 nm or less means that the ester compound is in a finely dispersed state in the toner. When the ester compound is finely dispersed, the interaction between the ester compound and the compound having the structure represented by formula (8) is weakened, the effect of softening the shell is reduced, and developability is further improved. Furthermore, when the ester compound is finely dispersed, the low-temperature fixing effect is more effectively exerted and deterioration of storage stability due to bleeding of the ester compound is also suppressed. The lower limit is not particularly limited, but is, for example, 130 nm or more. The number-average major axis of the ester compound is more preferably 150 to 250 nm.

[0035] As a method for finely dispersing the ester compound in the toner, for example, in the step of cooling an aqueous dispersion of colored resin particles (particles containing a binder resin and a colorant) in toner production, a method of rapidly cooling the aqueous dispersion of colored resin particles using cold water, ice, etc. Rapid cooling causes the ester compound to crystallize from a state in which it is dispersed in the binder resin, and the finely dispersed state can be maintained without forming large domains.

[0036] The content of the ester compounds represented by the formulas (1) to (7) is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the binder resin.

[0037] The shell contains a compound having a structure represented by formula (8). The shell containing the compound having the structure represented by formula (8) can suppress the exudation of the ester compound, thereby achieving both high developability and storage stability. In addition, the toner particle surface can be made positively charged, making it easy to use in image forming devices that use positively charged toner. In equation (8), R 14 is a linear alkyl group having 1 to 3 carbon atoms, preferably a methyl group or an ethyl group, and more preferably a methyl group.

[0038] A method for introducing a compound having a structure represented by formula (8) into the shell includes using methyl methacrylate as a polymerizable monomer for the shell. That is, the compound having the structure represented by formula (8) is preferably a resin having the structure represented by formula (8). Also, the compound having the structure represented by formula (8) is preferably a polymer of a polymerizable monomer for a shell, which includes a methacrylic acid alkyl ester having an alkyl group with 1 to 3 carbon atoms (more preferably 1 or 2, and even more preferably 1). The shell preferably includes polymethyl methacrylate. The secondary ion intensity at the surface of the toner and at a depth of 30 nm is measured by time-of-flight secondary ion mass spectrometry, and the secondary ion intensity corresponding to the structure expressed by formula (8) at a depth of 30 nm from the toner surface is divided by the sum of all secondary ion intensities at a depth of 30 nm from the toner surface to give A(30), and the secondary ion intensity corresponding to the structure expressed by formula (8) at the toner surface is divided by the sum of all secondary ion intensities at the toner surface to give A(0). It is preferable that A(0) and A(30) satisfy the relationships of the following formulas (9) and (10). 3.0≦A(0) / A(30)≦10.0 (9) 0.001≦A(30) (10)

[0039] When 0.001≦A(30) is satisfied and A(0) / A(30) is 3.0 or more, the formed shell has an appropriate thickness and exhibits excellent low-temperature fixability. On the other hand, when A(0) / A(30) is 10.0 or less, the shell is not too thin and exhibits excellent developability and storage stability. It is possible to demonstrate this. The relationship A(0) / A(30), that is, the thickness of the shell can be controlled by, for example, adjusting the amount of polymerizable monomer for the shell to be added. A(0) is preferably 0.010 to 0.020, more preferably 0.012 to 0.017. A(30) is more preferably 0.001 to 0.008, and more preferably 0.002 to 0.006. The value of A(0) / A(30) is more preferably 5.0 to 9.0, and even more preferably 6.0 to 8.0.

[0040] The toner may contain an elastomer. As the elastomer, an aromatic vinyl-based thermoplastic elastomer, or a conjugated diene-based elastomer such as polybutadiene rubber or polyisoprene rubber can be suitably used, but an aromatic vinyl-based thermoplastic elastomer is preferred, and a conjugated diene-aromatic vinyl-based thermoplastic elastomer is more preferred. Examples of the conjugated diene-aromatic vinyl thermoplastic elastomer include random, block, graft, and other copolymers of a conjugated diene monomer, an aromatic vinyl monomer, and, if necessary, other monomers copolymerizable therewith, and hydrogenated products of such copolymers.

[0041] The toner contains an aromatic vinyl thermoplastic elastomer, and the aromatic vinyl thermoplastic elastomer is preferably a diblock copolymer consisting of an aromatic vinyl polymer block and a polymer block copolymerizable with the aromatic vinyl polymer. By including an aromatic vinyl-based thermoplastic elastomer in the toner, the toner of the present disclosure can more effectively exhibit both low-temperature fixability and storage stability.

[0042] The polymer copolymerizable with the aromatic vinyl polymer is preferably a conjugated diene polymer, that is, the aromatic vinyl-based thermoplastic elastomer is preferably a conjugated diene-aromatic vinyl-based thermoplastic elastomer. The conjugated diene-aromatic vinyl thermoplastic elastomer is not particularly limited, but from the viewpoint of further improving the storage stability and low-temperature fixability of the toner, a block copolymer containing at least one aromatic vinyl polymer block and at least one conjugated diene polymer block can be suitably used.

[0043] Hereinafter, a block copolymer containing at least one aromatic vinyl polymer block and at least one conjugated diene polymer block (hereinafter sometimes simply referred to as "block copolymer"), which is a representative example of a conjugated diene-aromatic vinyl thermoplastic elastomer, will be described. The block copolymer contains at least one aromatic vinyl polymer block obtained by polymerizing an aromatic vinyl monomer and at least one conjugated diene polymer block obtained by polymerizing a conjugated diene monomer.

[0044] The aromatic vinyl monomer is not particularly limited as long as it is an aromatic vinyl compound, but may include at least one selected from the group consisting of styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, and vinylnaphthalene. Among these, styrene is preferred. These aromatic vinyl monomers may be used alone or in combination of two or more in each aromatic vinyl polymer block. Furthermore, when the block copolymer has a plurality of aromatic vinyl polymer blocks, each of the aromatic vinyl polymer blocks may be composed of the same aromatic vinyl monomer units or different aromatic vinyl monomer units.

[0045] The aromatic vinyl polymer block may contain other monomer units as long as aromatic vinyl monomer units are the main repeating units. Examples of other monomers that can be used in the aromatic vinyl polymer block include conjugated diene monomers such as 1,3-butadiene and isoprene (2-methyl-1,3-butadiene), α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or acid anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. The content of monomer units other than aromatic vinyl monomer units in the aromatic vinyl polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0046] The conjugated diene monomer is not particularly limited as long as it is a conjugated diene compound, but may include at least one selected from 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and / or isoprene are preferred, with isoprene being particularly preferred, from the viewpoint of achieving a high level of improvement in storage stability and low-temperature fixability. These conjugated diene monomers may be used alone or in combination of two or more in each conjugated diene polymer block. Furthermore, when the block copolymer has multiple conjugated diene polymer blocks, each conjugated diene polymer block may be composed of the same conjugated diene monomer units or different conjugated diene monomer units. Furthermore, a hydrogenation reaction may be performed on some of the unsaturated bonds in each conjugated diene polymer block.

[0047] The conjugated diene polymer block may contain other monomer units as long as the conjugated diene monomer units are the main repeating units. Examples of other monomers that can be used in the conjugated diene polymer block include aromatic vinyl monomers such as styrene and α-methylstyrene, α,β-unsaturated nitrile monomers, unsaturated carboxylic acid monomers, unsaturated carboxylic anhydride monomers, unsaturated carboxylic ester monomers, and non-conjugated diene monomers. The content of monomer units other than conjugated diene monomer units in the conjugated diene polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably substantially 0% by mass.

[0048] The vinyl bond content of the conjugated diene polymer block (the proportion of 1,2-vinyl bond units and 3,4-vinyl bond units in all conjugated diene monomer units in the conjugated diene polymer block) is not particularly limited, but is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and particularly preferably 3 to 10 mol%. The vinyl bond content of the conjugated diene polymer block is preferably from 7 to 67% by mass, more preferably from 14 to 59% by mass, and particularly preferably from 19 to 48% by mass.

[0049] The block copolymer is not particularly limited in the number of each polymer block or the bonding form thereof, as long as it contains at least one aromatic vinyl polymer block and one conjugated diene polymer block. Specific examples of block copolymers include the following. In the following specific examples, Ar represents an aromatic vinyl polymer block, D represents a conjugated diene polymer block, X represents a residue of a coupling agent, and n represents an integer of 2 or greater.

[0050] (a) Aromatic vinyl-conjugated diene block copolymer represented by Ar-D (b) Aromatic vinyl-conjugated diene represented by Ar-D-Ar and / or (Ar-D)nX Polyvinyl-aromatic vinyl block copolymer (c) Conjugated diene-aromatic vinyl-conjugated diene block copolymer represented by D-Ar-D and / or (D-Ar)nX (d) an aromatic vinyl-conjugated diene-aromatic vinyl-conjugated diene block copolymer represented by Ar-D-Ar-D; (e) A block copolymer composition comprising any combination of two or more of the above (a) to (d).

[0051] As the block copolymer, it is preferable to use one containing the aromatic vinyl-conjugated diene block copolymer represented by (a) Ar-D, and it is more preferable to use one containing the aromatic vinyl-conjugated diene block copolymer represented by (a) Ar-D and the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by (b) Ar-D-Ar and / or (Ar-D)nX. The content of the aromatic vinyl-conjugated diene block copolymer represented by Ar-D (i.e., a diblock copolymer consisting of an aromatic vinyl polymer block and a block of a polymer copolymerizable with the aromatic vinyl polymer) in the conjugated diene-aromatic vinyl thermoplastic elastomer is preferably 40 to 98 mass%, more preferably 50 to 98 mass% or more, and even more preferably 55 to 95 mass% or more.

[0052] In the aromatic vinyl-conjugated diene block copolymer represented by Ar-D, the weight average molecular weight (Mw(Ar)) of the aromatic vinyl polymer block Ar is not particularly limited, but is preferably 10,000 to 50,000, more preferably 15,000 to 30,000, and the weight average molecular weight (Mw(D)) of the conjugated diene polymer block D is not particularly limited, but is preferably 50,000 to 200,000, more preferably 60,000 to 150,000.

[0053] In addition, the weight average molecular weight (Mw(Ar)) of the aromatic vinyl polymer block Ar in the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar and / or (Ar-D)nX is not particularly limited, but is preferably 20,000 to 7 0000, more preferably 25000 to 50000, and the conjugated diene polymer block D The weight average molecular weight (Mw(D)) of the copolymer is not particularly limited, but is preferably 100,000 to 100,000. 300,000, more preferably 120,000 to 250,000.

[0054] The weight-average molecular weights are all polystyrene-equivalent values ​​measured by high-performance liquid chromatography (HPLC) using tetrahydrofuran as a carrier, as will be described in detail later.

[0055] The content of aromatic vinyl monomer units in the block copolymer relative to all monomer units is preferably 10 to 30 mass %, more preferably 12 to 25 mass %, and even more preferably 15 to 25 mass %.

[0056] The content and weight average molecular weight of the aromatic vinyl monomer unit in the block copolymer can be determined by the method described in Rubber Chem. Technol., 45, 1, 295 (1972) when all polymer components constituting the block copolymer are composed of only aromatic vinyl monomer units and conjugated diene monomer units. is subjected to ozonolysis and then reduced with lithium aluminum hydride, the conjugated diene monomer unit portion is decomposed and only the aromatic vinyl monomer unit portion can be isolated, so that the total aromatic vinyl monomer unit content and weight average molecular weight can be easily measured.

[0057] The weight average molecular weight (Mw) of the aromatic vinyl monomer unit in the block copolymer is not particularly limited, but can be determined by high performance liquid chromatography (H The polystyrene equivalent value measured by PLC is preferably 10,000 to 50,000, more preferably 20,000 to 40,000. The weight average molecular weight (Mw) of the conjugated diene monomer unit in the block copolymer is not particularly limited, but is preferably 50,000 to 200,000, more preferably 60,000 to 180,000.

[0058] The melt index (MI) of the block copolymer is not particularly limited, but is selected, for example, from the range of 1 to 1000 g / 10 min, and preferably from 5 to 30 g / 10 min, as a value measured in accordance with ASTM D-1238 (G conditions, 200°C, 5 kg). The weight average molecular weight of each block copolymer or monomer unit, as well as the melt index of the block copolymer, can be appropriately controlled by the amount of each monomer used, polymerization conditions, etc. By adjusting the weight average molecular weight and melt index to fall within the above preferred ranges, a toner having excellent fixability and heat-resistant storage stability can be obtained.

[0059] The block copolymer can be produced by a conventional method, for example, by anionic living polymerization, in which an aromatic vinyl monomer and a conjugated diene monomer are sequentially polymerized to form polymer blocks, and then, if necessary, a coupling agent is reacted to perform coupling.

[0060] Furthermore, when the block copolymer used contains the above-mentioned (a) aromatic vinyl-conjugated diene block copolymer represented by Ar-D and (b) aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar and / or (Ar-D)X, the following method can be employed.

[0061] Specifically, an aromatic vinyl monomer is first polymerized by anionic living polymerization, followed by the addition and polymerization of a conjugated diene monomer to obtain a diblock copolymer with an active end. Next, a coupling agent less than 1 molar equivalent is added to the active end of the diblock copolymer, resulting in a coupling reaction of a portion of the diblock copolymer with an active end, yielding an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by (Ar-D)nX. A polymerization terminator is then added to deactivate the remaining diblock copolymer with an active end, yielding a diblock copolymer represented by Ar-D. In this case, a bifunctional coupling agent such as dichlorosilane, monomethyldichlorosilane, dimethyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dichloroethane, dibromoethane, methylene chloride, or dibromomethane can be used as the coupling agent to obtain an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar (where D includes a residue of the coupling agent).

[0062] The content ratios of (a) the aromatic vinyl-conjugated diene block copolymer represented by Ar-D and (b) the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar and / or (Ar-D)nX are not particularly limited, but the content ratio of (a) the aromatic vinyl-conjugated diene block copolymer represented by Ar-D is preferably 10 to 90 mass%, more preferably 20 to 80 mass%. The content ratio of (b) the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented by Ar-D-Ar and / or (Ar-D)nX is preferably 10 to 90 mass%, more preferably 20 to 80 mass%.

[0063] Furthermore, as the conjugated diene-aromatic vinyl thermoplastic elastomer, a random copolymer of an aromatic vinyl monomer and a conjugated diene monomer can be used instead of the above-mentioned block copolymer. The random copolymer of an aromatic vinyl monomer and a conjugated diene monomer can be produced by living anionic polymerization using, for example, an organic alkali metal compound as a polymerization initiator. Examples of the organic alkali metal compound include organolithium compounds, Specific examples of the organic metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; organic polyvalent lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, and 1,3,5-tris(lithiomethyl)benzene; organic sodium compounds such as sodium naphthalene; and organic potassium compounds such as potassium naphthalene. Among these organic metal compounds, n-butyllithium is preferably used.

[0064] In the random copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the content of aromatic vinyl monomer units relative to all monomer units is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0065] The weight average molecular weight (Mw) of the block copolymer composition, which is an aromatic vinyl-based thermoplastic elastomer, is not particularly limited, but is preferably 60,000 to 350,000, and more preferably 80,000 to 250,000, in terms of polystyrene, measured by high performance liquid chromatography (HPLC) using tetrahydrofuran, as described below. The content of the block copolymer composition is preferably 1 to 10 parts by mass, more preferably 1.5 to 8 parts by mass, and even more preferably 2 to 5 parts by mass, relative to 100 parts by mass of the binder resin.

[0066] The volume average particle diameter (Dv) of the toner is preferably 3.0 μm to 9.0 μm, and more preferably 5.0 μm to 8.0 μm. By setting the volume average particle diameter (Dv) of the toner within the above range, the handling properties of the toner are improved and the developing device exhibits excellent developability. The Dv of the toner can be controlled by the amount of dispersant, the type of agitator, the rotation speed, and the like.

[0067] Each component constituting the toner and the method for producing the toner will be described in more detail below. <Binder resin> The polyester resin can be obtained by selecting and combining suitable compounds from polycarboxylic acids, polyols, hydroxycarboxylic acids, etc., and synthesizing them using a conventionally known method such as transesterification or polycondensation.

[0068] 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.

[0069] Examples of dicarboxylic 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.

[0070] Examples of polycarboxylic acids other than 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.

[0071] Polyols are compounds containing two or more hydroxyl groups in one molecule, and among these, diols are compounds containing two hydroxyl groups in one molecule and are preferably used. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 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, 1,14-eicosanedecanediol, and diethylene glycol , triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-butenediol, neopentyl glycol, 1,4-cyclohexanediol, 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.

[0072] Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferred, and alkylene oxide adducts of bisphenols and their combined use with alkylene glycols having 2 to 12 carbon atoms are particularly preferred.

[0073] Examples of trivalent or higher polyols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, sorbitol, trisphenol PA, phenol novolac, cresol novolac, and alkylene oxide adducts of the above trivalent or higher polyphenols. These may be used alone or in combination of two or more. The polyester resin may also be a polyester resin containing a urea group. It is preferable that the carboxyl groups at the terminals of the polyester resin are not capped.

[0074] Examples of the styrene-acrylic resin include homopolymers made of the following polymerizable monomers, copolymers obtained by combining two or more of these, and mixtures thereof. Styrenic monomers such as styrene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, and p-phenylstyrene;

[0075] Methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylic monomers such as (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, dimethyl phosphate ethyl (meth)acrylate, diethyl phosphate ethyl (meth)acrylate, dibutyl phosphate ethyl (meth)acrylate, and 2-benzoyloxyethyl (meth)acrylate, (meth)acrylonitrile, 2-hydroxyethyl (meth)acrylate, (meth)acrylic acid, and maleic acid; Vinyl ether monomers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketone monomers such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; Polyolefins such as ethylene, propylene, and butadiene.

[0076] The styrene-acrylic resin may contain a polyfunctional polymerizable monomer, if necessary. Examples of the polyfunctional polymerizable monomer include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2'-bis(4-((meth)acryloxydiethoxy)phenyl)propane, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.

[0077] In order to control the degree of polymerization, it is also possible to further add a known chain transfer agent and polymerization inhibitor.

[0078] Examples of polymerization initiators used in the production of toner particles by polymerization include persulfates such as potassium persulfate and ammonium persulfate; azo compounds such as 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile; and organic peroxides such as di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxydiethylacetate, t-hexylperoxy-2-ethylbutanoate, diisopropyl peroxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate. These can be used alone or in combination of two or more. Among these, it is preferable to use organic peroxides, since they can reduce the amount of residual polymerizable monomers and provide excellent print durability.

[0079] Among organic peroxides, peroxyesters are preferred because they have good initiator efficiency and can reduce the amount of residual polymerizable monomers, and non-aromatic peroxyesters, i.e., peroxyesters without an aromatic ring, are more preferred.

[0080] As described above, the polymerization initiator may be added after the polymerizable monomer composition is dispersed in an aqueous medium and before droplets are formed, or may be added to the polymerizable monomer composition before it is dispersed in an aqueous medium. The amount of the polymerization initiator used for polymerizing the polymerizable monomer composition is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 15 parts by mass, and particularly preferably 1 to 10 parts by mass, relative to 100 parts by mass of the polymerizable monomer.

[0081] The binder resin may contain a crystalline polyester, such as a condensation polymer of an aliphatic diol and an aliphatic dicarboxylic acid. It is preferably a condensation polymer of an aliphatic diol having from 2 to 12 carbon atoms and an aliphatic dicarboxylic acid having from 2 to 12 carbon atoms. Examples of the aliphatic diol having from 2 to 12 carbon atoms include the following compounds: 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.

[0082] Aliphatic diols having a double bond can also be used, such as 2-butene-1,4-diol, 3-hexene-1,6-diol, and 4-octene-1,8-diol.

[0083] Examples of aliphatic dicarboxylic acids having from 2 to 12 carbon atoms include the following compounds: 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, 1,12-dodecanedicarboxylic acid, lower alkyl esters and acid anhydrides of these aliphatic dicarboxylic acids.

[0084] Among these, sebacic acid, adipic acid, 1,10-decanedicarboxylic acid, and lower alkyl esters and acid anhydrides thereof are preferred. These may be used alone or in combination of two or more.

[0085] Aromatic dicarboxylic acids can also be used. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. Among these, terephthalic acid is preferred because it is easily available and can easily form a polymer with a low melting point.

[0086] 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.

[0087] 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. Among these, fumaric acid and maleic acid are more preferred.

[0088] 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.

[0089] The content of the crystalline polyester is preferably 1.0 to 30.0 parts by mass, and more preferably 3.0 to 25.0 parts by mass, relative to 100 parts by mass of the binder resin.

[0090] The peak temperature of the maximum endothermic peak of the crystalline polyester measured using a differential scanning calorimeter (DSC) is preferably 50.0 to 100.0°C, and more preferably 60.0 to 90.0°C from the viewpoint of low-temperature fixability.

[0091] The molecular weight of the binder resin is preferably such that the peak molecular weight Mp is 5,000 to 100,000, more preferably 10,000 to 40,000. The glass transition temperature T g is preferably 40 to 70° C., more preferably 40 to 60° C. The content of the binder resin is preferably 50% by mass or more with respect to the total amount of resin components in the toner particles.

[0092] <Crosslinking agent> When the toner particles are produced by a polymerization method, a crosslinking agent may be added. The amount of the crosslinking agent added is preferably 0.001 to 15 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

[0093] As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; ester compounds in which two or more carboxylic acids having carbon-carbon double bonds are ester-bonded to alcohols having two or more hydroxyl groups, such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; other divinyl compounds such as N,N-divinylaniline and divinyl ether; and compounds having three or more vinyl groups. These crosslinking agents can be used either alone or in combination of two or more.

[0094] <Release agent> In the toner, a known wax may be used in combination as a release agent in addition to the ester compounds represented by the formulas (1) to (7).

[0095] Specific examples include petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum and their derivatives, montan wax and its derivatives, hydrocarbon waxes produced by the Fischer-Tropsch process and their derivatives, polyolefin waxes such as polyethylene and polypropylene and their derivatives, and natural waxes such as carnauba wax and candelilla wax and their derivatives. Derivatives also include oxides, block copolymers with vinyl monomers, and graft-modified products.

[0096] The content of the release agent, in total with the content of the ester compounds represented by formulas (1) to (7), is preferably 1.0 to 30.0 parts by mass relative to 100.0 parts by mass of the binder resin.

[0097] The melting point of the release agent is preferably 30 to 120° C., more preferably 60 to 100° C. By using a release agent with a melting point of 30 to 120° C., the release effect is efficiently exerted and a wider fixing area is ensured.

[0098] <Coloring agent> The toner particles may contain colorants. When color toners are made, black, cyan, yellow, and magenta colorants can be used.

[0099] As the black colorant, for example, carbon black, titanium black, and magnetic powders such as iron zinc oxide and iron nickel oxide can be used.

[0100] Examples of cyan colorants that can be used include copper phthalocyanine compounds, derivatives thereof, and anthraquinone compounds, etc. Specific examples include CI Pigment Blue 2, 3, 6, 15, 15:1, 15:2, 15:3, 15:4, 16, 17:1, and 60.

[0101] As the yellow colorant, for example, azo pigments such as monoazo pigments and disazo pigments, and compounds such as condensed polycyclic pigments are used. Specifically, CI Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, 186, and 213.

[0102] Examples of magenta colorants that can be used include azo pigments such as monoazo pigments and disazo pigments, and condensed polycyclic pigments, etc. Specific examples include CI Pigment Red 31, 48, 57:1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 237, 238, 251, 254, 255, 269, and CI Pigment Violet 19.

[0103] Each colorant can be used alone or in combination of two or more kinds. The amount of the colorant is preferably 1 to 10 parts by mass based on 100 parts by mass of the polymerizable monomer.

[0104] <Charge control agents and charge control resins> To improve the chargeability of the toner, a positively or negatively chargeable charge control agent can be used.

[0105] The charge control agent is not particularly limited as long as it is a charge control agent generally used for toner. Among the charge control agents, a positively or negatively charged charge control resin is preferred because it has high compatibility with polymerizable monomers and can impart stable chargeability (charge stability) to toner particles. Furthermore, from the viewpoint of obtaining a positively charged toner, a positively charged charge control resin is more preferably used.

[0106] Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, and imidazole compounds, as well as preferably used charge control resins such as polyamine resins, quaternary ammonium group-containing copolymers, and quaternary ammonium base-containing copolymers. An example of a commercially available charge control resin is FCA-592P manufactured by Fujikura Chemical Co., Ltd.

[0107] Examples of negatively chargeable charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds, and metal alkylsalicylate compounds, as well as sulfonic acid group-containing copolymers, sulfonate salt group-containing copolymers, carboxylic acid group-containing copolymers, and carboxylic acid salt group-containing copolymers, which are preferably used as charge control resins.

[0108] The charge control agent is preferably used in an amount of 0.01 to 10 parts by mass, more preferably 0.03 to 8 parts by mass, per 100 parts by mass of the polymerizable monomer. When the amount of charge control agent added is 0.01 part by mass or more, fogging is less likely to occur. On the other hand, when the amount of charge control agent added is 10 parts by mass or less, print smearing is less likely to occur.

[0109] As other additives, it is preferable to use a molecular weight modifier when polymerizing the polymerizable monomer that becomes the binder resin after polymerization.

[0110] The molecular weight modifier is not particularly limited as long as it is a molecular weight modifier that is generally used for toners. Examples include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, and 2,2,4,6,6-pentamethylheptane-4-thiol; and thiuram disulfides such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N,N'-dimethyl-N,N'-diphenylthiuram disulfide, and N,N'-dioctadecyl-N,N'-diisopropylthiuram disulfide. These molecular weight modifiers may be used alone or in combination of two or more. The molecular weight modifier is used in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the polymerizable monomer.

[0111] <Method of manufacturing toner particles> The toner particles can be produced by a pulverization method, or by a method of producing toner particles in an aqueous medium, such as a dispersion polymerization method, an association aggregation method, a solution suspension method, a suspension polymerization method, or an emulsion aggregation method. However, from the viewpoint of controlling the state of existence of the ester compound and constructing a core-shell structure, a method of producing toner particles in an aqueous medium is preferred, and from the viewpoint of controlling the toner shape, it is more preferred to produce toner particles by a suspension polymerization method.

[0112] <Suspension polymerization method> The suspension polymerization method involves uniformly dissolving or dispersing a polymerizable monomer and wax (and, if necessary, a colorant, polymerization initiator, crosslinking agent, charge control agent, and other additives) to obtain a polymerizable monomer composition. This polymerizable monomer composition is then dispersed in a continuous layer (e.g., an aqueous phase) containing a dispersant using an appropriate stirrer, and a polymerization reaction is simultaneously carried out to obtain toner particles having a desired particle size. The toner particles obtained by this suspension polymerization method (hereinafter also referred to as "polymerized toner particles") have an approximately spherical shape, and therefore a relatively uniform charge distribution, which is expected to improve image quality.

[0113] It is preferable that the aqueous medium used in the granulation process contains a dispersion stabilizer in order to control the particle size of the toner particles, sharpen the particle size distribution, and prevent the coalescence of toner particles during the manufacturing process. Dispersion stabilizers are generally broadly classified into polymers that exhibit repulsive forces due to steric hindrance and poorly water-soluble inorganic compounds that stabilize dispersion by electrostatic repulsive forces. Fine particles of poorly water-soluble inorganic compounds are preferably used because they dissolve in acid or alkali and can be easily removed by washing with acid or alkali after polymerization.

[0114] In a method for producing toner particles by polymerization, the above-mentioned raw materials for the toner particles are generally added appropriately, and the polymerizable monomer composition is uniformly dissolved or dispersed using a dispersing machine such as a homogenizer, a ball mill, or an ultrasonic dispersing machine, and then suspended in an aqueous medium containing a dispersing agent. At this time, if a high-speed dispersing machine such as a high-speed stirrer or an ultrasonic dispersing machine is used to quickly obtain the desired toner particle size, the particle size of the obtained toner particles will become sharper.

[0115] The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before suspending the polymerizable monomer in an aqueous medium. Alternatively, the polymerization initiator dissolved in the polymerizable monomer or solvent may be added immediately after granulation and before starting the polymerization reaction. After the polymerization step, a cooling step is preferably carried out in which the temperature of the obtained toner particle dispersion is cooled to a temperature lower than the crystallization temperature or glass transition temperature of the binder resin by controlling the cooling rate. The cooling rate is, for example, 0.1 to 300°C / sec, preferably 1 to 200°C / sec, and more preferably 2 to 100°C / sec. The cooling step crystallizes the ester compound dispersed in the binder resin, and allows the ester compound to maintain a finely dispersed state without forming large domains.

[0116] After granulation, a conventional stirrer may be used to stir the mixture to such an extent that the particle state is maintained and the particles are prevented from floating or settling.

[0117] When producing toner particles, known surfactants, organic dispersants, and inorganic dispersants can be used as dispersants. Among them, inorganic dispersants provide dispersion stability due to their steric hindrance, so they are less likely to lose stability even when the reaction temperature is changed, are easy to wash, and do not adversely affect the toner. Examples of such inorganic dispersants include sulfates such as barium sulfate and calcium sulfate, carbonates such as barium carbonate, calcium carbonate and magnesium carbonate, phosphates such as calcium phosphate, metal oxides such as aluminum oxide and titanium oxide, and metal hydroxides such as aluminum hydroxide, magnesium hydroxide, sodium hydroxide and ferric hydroxide.

[0118] These inorganic dispersants are preferably used in an amount of 0.2 to 20 parts by mass per 100 parts by mass of the polymerizable monomer. The dispersants may be used alone or in combination of two or more. Furthermore, 0.001 to 0.1 parts by mass of a surfactant may be used in combination.

[0119] In the step of polymerizing the polymerizable monomer, the polymerization temperature is preferably 50° C. or higher, and more preferably 60 to 95° C. The polymerization reaction time is preferably 1 to 20 hours, and more preferably 2 to 15 hours.

[0120] The resulting polymer particles can be filtered, washed, and dried as needed by known methods to obtain toner particles. If necessary, a classification step can be performed to remove coarse particles and fine particles contained in the toner particles.

[0121] The obtained toner particles can be used as they are, or the toner can be obtained by mixing the toner particles with an external additive as needed and allowing the additive to adhere to the surface of the toner particles. The agitator used for the mixing process is not particularly limited as long as it is an agitator capable of adhering an external additive to the surface of toner particles, and the external addition process can be carried out using an agitator capable of mixing and stirring, such as FM Mixer (trade name, manufactured by Nippon Coke and Engineering Co., Ltd.), Super Mixer (trade name, manufactured by Kawada Manufacturing Co., Ltd.), Q Mixer (trade name, manufactured by Nippon Coke and Engineering Co., Ltd.), Mechanofusion System (trade name, manufactured by Hosokawa Micron Corporation), and Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.).

[0122] Examples of external additives include inorganic fine particles such as silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate, and cerium oxide; and organic fine particles such as polymethyl methacrylate resin, silicone resin, and melamine resin. Among these, inorganic fine particles are preferred, and among inorganic fine particles, silica and titanium oxide are preferred, with silica being more preferred. These external additives can be used either alone or in combination of two or more. These external additives may be made hydrophobic by surface treatment. The content of the external additive is preferably 0.05 to 6 parts by mass, and more preferably 0.2 to 5 parts by mass, relative to 100 parts by mass of the toner particles.

[0123] Furthermore, to further refine these dispersion stabilizers, a surfactant may be used in an amount of 0.001 to 0.1 parts by mass per 100 parts by mass of the polymerizable monomer. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and calcium oleate are preferably used.

[0124] The methods for measuring the physical properties of the toner and each material will be described below. <Method for measuring the weight average molecular weight (Mw) of binder resin> 0.1 g of precisely weighed toner was placed in each 100 mL glass sample bottle, and then 49.9 g of tetrahydrofuran (THF) was added to each bottle. Next, a stirrer tip was placed in each bottle. After stirring for 1 hour at room temperature using a magnetic stirrer, the mixture was filtered through a 0.2 μm PTFE filter to obtain a THF solution of the binder resin. Finally, 100 μL of each THF solution was injected into a GPC analyzer for GPC measurement. The weight-average molecular weight (Mw) was calculated based on the obtained GPC elution curve and a calibration curve using commercially available monodisperse standard polystyrene. When the toner contains an external additive, the external additive can be removed by a method for separating toner particles from the toner, which will be described later, and then the measurement can be carried out in the same manner as above.

[0125] (GPC measurement conditions) GPC: HLC-8220 (Tosoh Corporation) Column: TSK-GELMULTIPEHXL-M2 (Tosoh Corporation) Eluent:THF Flow rate: 1.0mL / min Temperature: 40℃

[0126] <Method for identifying the structure and content of ester compounds> (Separation method) Separation of toner particles from toner The toner particles obtained by separating the toner particles from the external additives by the following method can be used for each analysis. Add 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchanged water and dissolve in a hot water bath to prepare a sucrose solution. Place 31 g of the 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 Fujifilm Wako Pure Chemical Industries, Ltd.) in a centrifuge tube to prepare a dispersion. Add 1 g of toner to this dispersion and break up any clumps of toner with a spatula or similar.

[0127] The centrifuge tube is placed in a KM Shaker (model V.SX) manufactured by Iwaki Sangyo Co., Ltd. and shaken for 20 minutes at 350 strokes per minute. After shaking, the solution is transferred to a glass tube (50 mL) for a swing-out rotor and centrifuged at 3500 rpm for 30 minutes in a centrifuge (H-9R manufactured by Kokusan Co., Ltd.). After centrifugation, the toner particles are in the top layer of the glass tube, and external additives such as silica microparticles are in the aqueous solution below. The toner particles in the top layer are collected and filtered, then washed with 2 L of ion-exchanged water heated to 40°C, and the washed toner particles are removed.

[0128] The toner particles are dissolved in tetrahydrofuran (THF), and the solvent is removed from the resulting soluble matter by distillation under reduced pressure to obtain the THF-soluble component of the toner particles. The THF-soluble component of the obtained toner particles is dissolved in chloroform to prepare a sample solution with a concentration of 25 mg / mL.

[0129] 3.5 mL of the obtained sample solution is poured into the following apparatus, and fractions with a number average molecular weight (Mn) of less than 2000 are collected under the following conditions. Preparative GPC device: Preparative HPLC LC-980 model manufactured by Japan Analytical Industry Co., Ltd. Preparative column: JAIGEL 3H, JAIGEL 5H (manufactured by Nippon Analytical Industry Co., Ltd.) Eluent: chloroform Flow rate: 3.5mL / min

[0130] The molecular weight of the sample was calculated using a molecular weight calibration curve prepared using standard polystyrene resins (e.g., 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). Use.

[0131] If necessary, silica gel column chromatography (developing solvent: chloroform, toluene) The components are further fractionated using solvents (solvents: acetone, hexane, methanol, etc.) or the solid is separated using recrystallization (solvent: acetone, hexane, etc.), after which the solvent is distilled off and the mixture is dried by heating under reduced pressure. Repeat the above procedure until you have obtained approximately 100 mg of each ingredient.

[0132] (Identifying structure and content) The structure of the separated components was confirmed by nuclear magnetic resonance spectroscopy ( 1 The compound is characterized using H-NMR [400 MHz, CDCl3, room temperature (25°C)]. Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measurement frequency: 400MHz Pulse condition: 5.0 μs Frequency range: 10500Hz Accumulation count: 64 times Furthermore, the NMR measurement of the toner is carried out using the above-mentioned method, and the content is determined from the spectral intensity by comparing with the isolated components.

[0133] <Method for measuring the number-average major axis of ester compounds when observing the cross section of a toner with a transmission electron microscope> Cross-sectional observation of the toner using a scanning transmission electron microscope (STEM) is carried out as follows. When the toner contains a crystalline resin, the cross section of the toner is stained with ruthenium for observation. The crystalline resin contained in the toner is more easily stained with ruthenium than an amorphous resin such as a binder resin, resulting in clearer contrast and easier observation. The amount of ruthenium atoms varies depending on the strength of the staining, so areas that are strongly stained have a large amount of these atoms, and the electron beam does not pass through, appearing black in the observation image. Areas that are weakly stained allow the electron beam to easily pass through, appearing white in the observation image.

[0134] First, place the toner on a cover glass (Matsunami Glass Co., Ltd., square cover glass No. 1). The toner was sprayed in layers, and an osmium plasma coater (Filgen, OPC80T) was used to coat the toner with a protective layer of Os (5 nm) and naphthalene (20 nm). Next, a PTFE tube (1.5 mm inner diameter x 3 mm outer diameter x 3 mm) was filled with photocurable resin D800 (JEOL Ltd.), and the cover glass was gently placed on top of the tube, with the toner in contact with the photocurable resin D800. The resin was then cured by irradiating it with light, and the cover glass and tube were removed to form a cylindrical resin with the toner embedded in its outermost surface. An ultrasonic ultramicrotome (Leica, UC7) was used to cut the outermost surface of the cylindrical resin at a cutting speed of 0.6 mm / s, along the radius of the toner (4.0 μm for a weight-average particle diameter (D4) of 8.0 μm) to expose the toner cross-section. Next, a thin section of the toner cross-section was prepared by cutting to a thickness of 250 nm. By cutting in this manner, a cross section of the central part of the toner can be obtained.

[0135] The obtained thin section sample is stained for 15 minutes in a 500 Pa atmosphere of RuO4 gas using a vacuum electron staining device (Filgen, VSC4R1H), and then subjected to STEM observation using a scanning transmission electron microscope (JEOL, JEM2800).

[0136] The STEM probe size was 1 nm, and the image size was 1024 x 1024 pixels. For the bright-field image, the Contrast on the Detector Control panel was set to 1425, the Brightness to 3750, and the Contrast on the Image Control panel to 0.0, Brightness to 0.5, and Gamma to 1. Adjust to 00 and capture the image. In the present disclosure, the number average diameter of an ester compound refers to the number average diameter determined from the major axis of the domains of the ester compound based on a STEM image. The number-average diameter of the major axis of the ester compound domains is measured based on a STEM image obtained by observing the cross section of a toner particle stained with ruthenium using a scanning transmission electron microscope (STEM). The cross sections of 100 toner particles are observed. All domains are measured, and the number-average diameter is calculated. The obtained number-average diameter is the number-average diameter of the major axis of the ester compound domains.

[0137] <Method for identifying shell structure containing compound having structure represented by formula (8)> The shell structure was determined by nuclear magnetic resonance spectroscopy ( 1 The compound is characterized using H-NMR [400 MHz, CDCl3, room temperature (25°C)].

[0138] Measuring device: FT NMR device JNM-EX400 (manufactured by JEOL Ltd.) Measurement frequency: 400MHz Pulse condition: 5.0 μs Frequency range: 10500Hz Accumulation count: 64 times Solvent: Use a deuterated solvent that dissolves the toner.

[0139] The measurement sample is prepared by immersing 10 mg of toner in a solvent, leaving it for 1 minute, filtering it, and using the filtrate as the measurement sample.

[0140] <Method for measuring secondary ion intensity using time-of-flight secondary ion mass spectrometry (TOF-SIMS)> A(0) and A(30) are calculated from the secondary ion intensity measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS). To measure secondary ion intensity using TOF-SIMS, nanoTOFII manufactured by ULVAC-PHI, Inc. was used. The analysis conditions are as follows.

[0141] Sample preparation: Adhesion of toner to an indium sheet Sample preparation: None Primary ion: Bismuth trimer ion (Bi3 ++ ) Accelerating voltage: 30 kV Charge neutralization mode: On Measurement mode: Negative Raster: 300 μm Measurement time: 30s

[0142] Calculation of secondary ion intensity corresponding to the structure represented by formula (8): The total count number of mass numbers 84.5 to 85.5 was calculated according to the standard software (Win Cadense) of ULVAC-PHI. TOF-SIMS is usually a surface analysis method, and the depth data is approximately 1 nm. Therefore, to measure the secondary ion intensity inside the toner, the toner is sputtered with argon gas cluster ions and the surface is scraped off.

[0143] The sputtering conditions were as follows: Accelerating voltage: 10 kV Current: 10nA Raster: 600 μm Irradiation time: 5 seconds

[0144] To measure the depth, we confirmed the relationship between irradiation time and the depth of removal by sputtering a polymethyl methacrylate (PMMA) film under the same conditions in advance, and confirmed that 100 nm could be removed in 300 seconds.

[0145] The secondary ion intensity at a depth of 30 nm from the toner surface is the value of secondary ion mass / secondary ion charge number (m / z) measured when sputtering is performed 18 times under the above conditions. The secondary ion intensity on the surface of the toner is the value of secondary ion mass / secondary ion charge number (m / z) measured without sputtering the toner. A(30) is the value obtained by dividing the secondary ion intensity corresponding to the structure expressed by formula (8) at a depth of 30 nm from the toner surface by the sum of all secondary ion intensities at a depth of 30 nm from the toner surface. Furthermore, the value obtained by dividing the secondary ion intensity corresponding to the structure expressed by formula (8) on the toner surface by the sum of all secondary ion intensities on the toner surface is A(0).

[0146] <Analysis methods for conjugated diene-aromatic vinyl thermoplastic elastomers> (1) Weight average molecular weight of conjugated diene-aromatic vinyl thermoplastic elastomer The molecular weight is determined as a polystyrene equivalent by high-performance liquid chromatography using tetrahydrofuran as a carrier at a flow rate of 0.35 mL / min. The instrument used is a Tosoh HLC8220, and the column is a combination of three Showa Denko Shodex® KF-404HQ columns (column temperature: 40°C). The detectors are a differential refractometer and an ultraviolet detector. The molecular weight is calibrated using 12 standard polystyrenes (weight-average molecular weight: 5,000,000 to 3,000,000) manufactured by Polymer Laboratory.

[0147] (2) Content of each block copolymer in the conjugated diene-aromatic vinyl thermoplastic elastomer It is determined from the area ratio of the peaks corresponding to each block copolymer in the chart obtained by the above high performance liquid chromatography.

[0148] (3) Weight average molecular weight of the aromatic vinyl polymer block of the block copolymer that constitutes the conjugated diene-aromatic vinyl thermoplastic elastomer According to the method described in Rubber Chem. Technol., 45, 1295 (1972), the conjugated diene polymer block of the block copolymer is decomposed by reacting the block copolymer with ozone and reducing it with lithium aluminum hydride. Specifically, for example, when the conjugated diene polymer block is an isoprene polymer block, the following procedure is carried out. Specifically, 300 mg of sample was dissolved in a reaction vessel containing 100 mL of molecular sieve-treated dichloromethane. The reaction vessel was then placed in a cooling bath and cooled to -25°C. Ozone generated by an ozone generator was then introduced into the reaction vessel while oxygen was flowing into the reaction vessel at a flow rate of 170 mL / min. Thirty minutes after the start of the reaction, completion of the reaction was confirmed by introducing the gas escaping from the reaction vessel into the potassium iodide aqueous solution. Next, 50 mL of diethyl ether and 470 mg of lithium aluminum hydride were placed in a separate reaction vessel purged with nitrogen. While cooling the reaction vessel with ice water, the ozone-reacted solution was slowly added dropwise to the reaction vessel. The reaction vessel was then placed in a water bath, gradually heated, and refluxed at 40°C for 30 minutes. While stirring the solution, dilute hydrochloric acid was gradually added dropwise to the reaction vessel, continuing the addition until hydrogen generation was almost completely eliminated. After this reaction, the solid product formed in the solution is filtered off and extracted with 100 mL of diethyl ether for 10 minutes. This extract and the filtrate are combined, and the solvent is evaporated to obtain a solid sample. The weight-average molecular weight of the sample thus obtained is measured according to the above-mentioned method for measuring weight-average molecular weight, and the measured value is regarded as the weight-average molecular weight of the aromatic vinyl polymer block.

[0149] (4) Weight average molecular weight of the conjugated diene polymer block of the block copolymer constituting the conjugated diene-aromatic vinyl thermoplastic elastomer The weight average molecular weight of the aromatic vinyl polymer block is subtracted from the weight average molecular weight of the corresponding block copolymer determined as above, and the weight average molecular weight of the conjugated diene polymer block is determined based on the calculated value.

[0150] (5) Aromatic vinyl unit content of the block copolymer constituting the conjugated diene-aromatic vinyl thermoplastic elastomer The value is determined based on the ratio of the detected intensities obtained by the differential refractometer and the ultraviolet detector in the high performance liquid chromatography measurement. Copolymers having different aromatic vinyl unit contents are prepared in advance, and a calibration curve is prepared using these copolymers.

[0151] (6) Vinyl bond content of the conjugated diene polymer block of the block copolymer constituting the conjugated diene-aromatic vinyl thermoplastic elastomer 1 Measurement is performed by H-NMR, and the value is determined based on the resulting chart. The measurement device and conditions are the same as those used to identify the structure of the ester compound and the shell structure.

[0152] (7) Aromatic vinyl unit content of conjugated diene-aromatic vinyl thermoplastic elastomer 1 Measurement is performed by H-NMR, and the value is determined based on the resulting chart. The measurement device and conditions are the same as those used to identify the structure of the ester compound and the shell structure.

[0153] (8) Melt index of conjugated diene-aromatic vinyl thermoplastic elastomer Measurement was performed in accordance with ASTM D1238 (G condition, 200°C, 5 kg load).

[0154] <Method for measuring the volume average particle diameter Dv of the toner> The volume average diameter of the toner is calculated as follows. The measurement device used is 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 hole electrical resistance method. The measurement conditions are set and the measurement data is analyzed using the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (Beckman Coulter, Inc.). The measurement will be carried out using an effective number of measurement channels of 25,000.

[0155] The 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, for example, "ISOTON II" (Beckman-Coller, (manufactured by Tarter Co., Ltd.) can be used. Before carrying out the measurement and analysis, the dedicated software is set up as follows. On the "Change Standard Measurement Method (SOMME)" screen of the dedicated software, set the total count number in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (manufactured by 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, and the electrolyte to ISOTON II, and then click " Check "Flush aperture tube after measurement."

[0156] On the "Pulse to particle size conversion setting" screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bins, and the particle size range is set to 2 μm to 60 μm.

[0157] The specific measurement method is as follows. (1) Place the electrolytic solution in a 250 mL round-bottom glass beaker made specifically for the Multisizer 3. Add approximately 200 mL of liquid, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "Aperture Tube Flush" function of the dedicated software to remove any dirt and air bubbles from inside the aperture tube. (2) Approximately 30 mL of the above-mentioned aqueous electrolyte solution is placed in a 100 mL flat-bottom glass beaker, and approximately 0.3 mL of a solution prepared by diluting Contaminon N (a 10% 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.) as a dispersant with ion-exchanged water by approximately three times its mass is added. (3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetra150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and two built-in oscillators with an oscillation frequency of 50 kHz, with a phase difference of 180 degrees. Pour approximately 3.3 L of ion-exchanged water into the tank and add approximately 2 mL of Contaminon N to the tank. (4) Place the beaker from (2) into the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height of the beaker so that the resonance state of the liquid surface of the electrolyte solution in the beaker is maximized. (5) While the electrolyte solution in the beaker in (4) is irradiated with ultrasonic waves, 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, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C. (6) Using a pipette, the electrolytic solution (5) containing the dispersed toner is dropped into the round-bottom beaker (1) placed in the sample stand, and the measurement concentration is adjusted to approximately 5%. Then, measurements are continued until the number of particles measured reaches 50,000. (7) The measurement data is analyzed using the dedicated software attached to the device, and the calculated volume-based median diameter is taken as the volume-average particle diameter Dv of the toner.

[0158] <Developer Carrier> A developer carrier of a developing device according to at least one aspect of the present disclosure includes a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate. One embodiment of the developer carrier is a developing roller. An example of a developing roller is shown in Fig. 1. The developing roller 10 shown in Fig. 1 has a resin layer 12 laminated on the outer surface side of a columnar or hollow cylindrical substrate 11. The layer configuration of the developing roller is not limited to the form shown in Fig. 1. As another form of the developing roller, as shown in Fig. 2, an elastic layer 13 may be provided between a base 11 and a resin layer 12 provided on the outer peripheral surface thereof.

[0159] The resin layer contains carbon black. Carbon black acts as a hard domain in the resin layer to reduce the contact area with the toner, thereby reducing the adhesive force and improving the developability.

[0160] The arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is 80.0 nm or less. By highly dispersing carbon black in the resin layer to such an extent that the arithmetic mean value Rc of the equivalent circle diameter of the carbon black is 80.0 nm or less, the contact opportunity between the toner on the surface of the developing roller and the carbon black in the resin layer of the developing roller increases, resulting in a high development effect. The arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is preferably 70.0 nm or less, and more preferably 60.0 nm or less. The lower limit of Rc is not particularly limited, but preferred ranges of Rc include, for example, 40.0 to 80.0 nm, 40.0 to 70.0 nm, and 50.0 to 60.0 nm.

[0161] Furthermore, when the standard deviation of the circle-equivalent diameter is σc [nm], σc / Rc is preferably 0.000 to 0.650, and more preferably 0.500 to 0.620. The equivalent circle diameter of the carbon black in the resin layer can be adjusted, for example, by appropriately changing the DBP (dibutyl phthalate) absorption amount or pH of the carbon black species used.

[0162] The arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer of the developing roller is 60.0 to 170.0 nm.

[0163] When the arithmetic mean value d of the distance between the wall surfaces of the carbon black is 60.0 nm or more, the carbon black can be maintained in a highly dispersed state without aggregation in the resin layer, and the toner and carbon black can be in contact frequently, thereby exhibiting good development performance. On the other hand, when the arithmetic mean value d of the distance between the wall surfaces of the carbon black is 170.0 nm or less, the carbon black is present at appropriate intervals in the resin layer, resulting in a highly uniform hardness of the developing roller surface, which allows the toner to roll well on the developing roller and facilitates development. The arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer is 70.0 to 160.0 nm. Preferably, σd / d is 0.000 to 0.600, more preferably 0.400 to 0.580, where σd [nm] is the standard deviation of the distance between the wall surfaces.

[0164] The distance between the wall surfaces of the carbon black in the resin layer can be adjusted, for example, by appropriately changing the amount of carbon black added.

[0165] The content of carbon black in the resin layer is preferably 30 parts by mass or less, more preferably 10 to 30 parts by mass, and even more preferably 15 to 25 parts by mass, relative to 100 parts by mass of polyurethane forming the resin layer.

[0166] When the amount is 30 parts by mass or less, the distance between the carbon black particles in the coating liquid is maintained at an appropriate level, reducing the probability of collisions due to Brownian motion of the carbon black and making the carbon black less likely to aggregate. This makes the carbon black more easily dispersible and improves dispersion stability. As a result, the carbon black is well dispersed in the resin layer formed by coating the coating liquid.

[0167] The carbon black preferably has a number average diameter of primary particles of 30 nm or less, a DBP absorption of 90 mL / 100 g or less, and a pH of 4.0 or less.

[0168] When the number-average diameter of the primary particles of carbon black is 30 nm or less, the aggregates (primary agglomerates), which are the smallest dispersible units of carbon black, become small, allowing for high dispersion in the resin layer of the developing roller. The primary particle diameter of carbon black can be calculated using a transmission electron microscope (TEM). The lower the number-average diameter, the better, and there is no particular lower limit. For example, the number-average diameter of the primary particles of carbon black is preferably 5 to 30 nm, and more preferably 20 to 28 nm.

[0169] When the DBP absorption of carbon black is 90 mL / 100 g or less, the carbon black structure becomes small and can be highly dispersed in the resin layer of the developing roller. The lower the DBP absorption, the better, and there is no particular lower limit. For example, the DBP absorption of carbon black is preferably 30 to 90 mL / 100 g, and more preferably 40 to 60 mL / 100 g.

[0170] When the pH of carbon black is 4.0 or less, the repulsion of the surface functional groups of the carbon black provides dispersion stability, making the carbon black less likely to aggregate and allowing it to be highly dispersed in the resin layer of the developing roller. The lower the pH of carbon black, the more preferable it is, and there is no particular lower limit. For example, the pH of carbon black is more preferably 2.0 to 4.0, and more preferably 2.2 to 2.8. In this disclosure, pH is measured at 20°C unless otherwise specified.

[0171] When polycarbonate urethane is used as the binder resin, it is preferable to add the additives described below, as this improves the dispersibility of carbon black. The reason for this is not clearly understood, but is speculated as follows.

[0172] The hydroxyl groups, which are surface functional groups of carbon black, tend to interact with the terminal hydroxyl groups of polycarbonate diol. On the other hand, the structure of the carbonate bond and hydrocarbon group bonded between the two hydroxyl groups of polycarbonate diol is hydrophobic due to the presence of the hydrocarbon group, making it less likely to interact with carbon black. Since the structure is more stable when hydrophobic functional groups and hydrophilic functional groups are close to each other, hydrophilic carbon black tends to exist near other hydrophilic carbon black. However, the addition of additives, described below, causes interactions between the additives and the carbon black. As a result, it is thought that carbon black is less likely to aggregate and is easier to disperse.

[0173] It is preferable that the relationship between the volume average particle diameter Dv of the toner and the arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer satisfies the following formula (11). 50.0≦Dv / d≦100.0 (11) When the value of Dv / d is within the range of the formula (11), the toner and the carbon black in the resin layer of the developing roller come into contact with each other more easily, and higher developability can be achieved. The value of Dv / d is more preferably from 50.0 to 80.0, and further preferably from 60.0 to 70.0.

[0174] The components constituting the developing roller and the method for manufacturing the developing roller will be described in more detail below. [Base] The substrate has a conductive outer surface and functions as a support member for the developing roller and, in some cases, as an electrode. Specific examples of the substrate preferably have a solid columnar or hollow cylindrical shape.

[0175] The material for the substrate can be appropriately selected from those known in the field of electroconductive members for electrophotography and materials usable for such developing rollers, and examples thereof include metals or alloys such as aluminum and stainless steel, carbon steel alloys, conductive synthetic resins, iron, and copper alloys.

[0176] Furthermore, the material constituting the substrate may be subjected to an oxidation treatment or a plating treatment with chromium, nickel, or the like. Either electroplating or electroless plating can be used as the type of plating. Electroless plating is preferred from the viewpoint of dimensional stability. Examples of electroless plating that can be used here include nickel plating, copper plating, gold plating, and various other alloy platings. The plating thickness is preferably 0.05 μm or more, and considering the balance between work efficiency and rust prevention ability, the plating thickness is preferably 0.1 to 30 μm.

[0177] A primer may be applied to the surface of the substrate in order to improve the adhesion between the substrate and the resin layer. As the primer, a known primer can be selected and used depending on the rubber material for forming the conductive layer and the material of the support. Examples of the primer material include thermosetting resins. Examples of the material include a phenolic resin, a polyurethane, an acrylic resin, a polyester resin, a polyether resin, and an epoxy resin.

[0178] [Resin layer] The developing roller has a resin layer on the outer surface side of the substrate. For example, the resin layer is present on the outer surface of the developing roller. The resin layer may contain a binder resin. As the binder resin of the resin layer in the developing roller, polyurethane is preferably used to suppress charge leakage from the toner to the developing roller. The polyurethane preferably has at least one selected from the group consisting of a polyether structure and a polycarbonate structure, and more preferably has a polycarbonate structure. In other words, the resin layer more preferably contains polyurethane having a polycarbonate structure. The polycarbonate structure provides high surface strength and good electrical resistance, making it easier to maintain the properties of the developing roller throughout its durability.

[0179] Furthermore, in order to suppress charge leakage from the toner to the developing roller while maintaining a light load on the toner and sufficient abrasion resistance of the resin layer, it is more preferable that the resin layer contains polyurethane having the structure described below.

[0180] The resin layer contains polyurethane, and the polyurethane preferably satisfies at least two of the following (A), (B), and (C). It may also satisfy all of the following (A), (B), and (C). (A) The polyurethane has a structure represented by the following structural formula (I) in its molecule; (B) The polyurethane has, in its molecule, either one or both of a structure represented by the following structural formula (II) and a structure represented by the following structural formula (III): (C) The polyurethane has a structure represented by the following structural formula (IV) in the molecule.

[0181] That is, it is preferable that the polyurethane satisfies at least one of the following requirements. ·Having at least a structure represented by structural formula (I) and a structure represented by structural formula (II). ·Having at least a structure represented by structural formula (I) and a structure represented by structural formula (III). ·Having at least a structure represented by structural formula (I) and a structure represented by structural formula (IV). ·Having at least a structure represented by structural formula (II) and a structure represented by structural formula (IV). ·Having at least a structure represented by structural formula (III) and a structure represented by structural formula (IV).

[0182] Among these, from the viewpoint of better fogging suppression and image density stability, it is more preferable that the polyurethane has at least the structure represented by structural formula (I) and the structure represented by structural formula (IV) in the molecule.

[0183] [ka]

[0184] [ka]

[0185] [ka]

[0186] [ka]

[0187] In structural formula (I), R13, R14, and R15 represent divalent hydrocarbon groups having 3 to 9 carbon atoms. However, R13 and R14 are different from each other, and R15 is the same as at least one selected from the group consisting of R13 and R14. m and n represent the average number of moles added, and each independently represents a number of 1.0 or more (preferably 1.0 to 20.0, more preferably 2.0 to 12.0).

[0188] In structural formula (II), o and p are the average number of moles added, and each independently represents a number of 1.0 or more (preferably 1.0 to 15.0, more preferably 4.0 to 10.0). In structural formula (III), R16 and R17 each independently represent a divalent hydrocarbon group having 3 to 8 carbon atoms. q and r each independently represent the average number of moles added and are 1.0 or greater (preferably 1.0 to 20.0, more preferably 2.0 to 14.0). In structural formula (IV), R18 represents a divalent hydrocarbon group having 6 to 9 carbon atoms (preferably 5 to 8). s represents the average number of moles added and is 1.0 or more (preferably 1.0 to 22.0, more preferably 4.0 to 18.0).

[0189] The structure shown in structural formula (I) is a copolymer polycarbonate polyol in which crystallinity is reduced by linking two carbonate groups with two different hydrocarbon groups, and the polyol is reacted with isocyanate. Because the crystallinity is reduced, the cohesive energy in the soft segments is small, which gives the resin layer flexibility and high volume resistivity. By using the structure of structural formula (I) in combination with the structures (II) to (IV) described above in the resin layer, the adhesiveness of the resin layer can be reduced, which prevents toner, powder, etc. from adhering to the surface of the resin layer, suppresses an increase in the electrical resistance of the surface of the resin layer due to contamination, and facilitates uniform charging of the toner.

[0190] If R13 and R14 each have 3 or more carbon atoms, the amount of carbonate groups, which are polar functional groups with strong cohesive energy, in the polyurethane will not be too large, making it easier to maintain the resin layer flexible and with a high electrical resistance.

[0191] In addition, if the carbon number of R13 and R14 is 9 or less, the carbonate group in the polyurethane The amount is not too small, and the strength of the polymer can be maintained. Furthermore, when R13 and R14 have different structures, the crystallinity of the polymer can be suppressed and flexibility can be imparted to the resin layer. The hydrocarbon groups represented by R13, R14, and R15 may have a branched structure or a cyclic structure.

[0192] The structures shown in structural formulas (II) and (III) are obtained by reacting a copolymer polyol, which is a copolymer of a polycarbonate structure and a polyester structure, with an isocyanate. By copolymerizing the polycarbonate structure and the polyester structure, the crystallinity of the polymer is suppressed, and by introducing an ester group, which has a stronger cohesive energy than the carbonate group, the soft segment is appropriately reinforced, thereby imparting abrasion resistance to the resin layer. When a resin layer is formed using a polymer in which the structure represented by structural formula (II) and / or structural formula (III) is combined with the structure represented by formula (I) or (IV) described above, the resin layer can be given sufficient volume resistivity while having a polar ester group, making it easier to suppress charge leakage from the toner to the developing roller.

[0193] If R16 and R17 each have 3 or more carbon atoms, the amount of carbonate and ester groups in the polyurethane, which are polar functional groups with strong cohesive energy, will not be too large, allowing the resin layer to remain flexible. If R16 and R17 each have 8 or less carbon atoms, the amount of carbonate and ester groups in the polyurethane will not be too small, allowing the resin layer to be imparted with abrasion resistance.

[0194] The structure represented by structural formula (IV) is a structure obtained by reacting a highly crystalline polycarbonate polyol, in which two carbonate groups are bonded by a single hydrocarbon group, with an isocyanate. This structure has high crystallinity and is easily aligned in the soft segment, which can impart abrasion resistance and high volume resistivity to the resin layer. By forming a resin layer using a polymer in which the structure represented by structural formula (IV) is combined with the structures of formulas (I) to (III) above, the hardness of the resin layer does not become too high and can be easily controlled appropriately.

[0195] When R18 has 6 or more carbon atoms, crystallinity is easily exhibited, and the resin layer can be imparted with abrasion resistance and high volume resistivity. When R18 has 9 or less carbon atoms, excessive crystallinity can be suppressed, and therefore, by further containing at least one structure represented by structural formulas (I), (II), and (III) in the polymer, an increase in the hardness of the resin layer can be suppressed.

[0196] The resin layer preferably contains a polymer having a urethane bond, i.e., polyurethane, as a binder resin, and the polymer preferably satisfies at least two selected from the group consisting of (A), (B), and (C) above, which makes the resin layer flexible and less susceptible to wear.

[0197] The structure of the polymer contained in the resin layer of the developing roller can be confirmed by, for example, pyrolysis GC / MS, FT-IR, or NMR analysis.

[0198] Polyurethane can be produced using (A) a polyol compound and (B) a polyisocyanate compound. Polyurethane is usually synthesized by the following methods (1) and (2). (1) One-shot method in which the polyol component and the polyisocyanate component are mixed and reacted (2) A method in which an isocyanate-terminated prepolymer obtained by reacting a part of a polyol with an isocyanate is reacted with a chain extender such as a low molecular weight diol or low molecular weight triol.

[0199] In the present disclosure, polyurethane may be synthesized by any of the above methods, but the use of a hydroxyl-terminated prepolymer obtained by reacting a raw material polyol with an isocyanate and a hydroxyl-terminated prepolymer obtained by reacting a raw material polyol with an isocyanate is also preferred. A more preferred method is to subject the prepolymer to a thermal curing reaction with an isocyanate-terminated prepolymer that has been reacted with an anate.

[0200] The polyurethane is preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer and an isocyanate-terminated prepolymer. The mixture can be used as a coating liquid for forming a resin layer. The polyurethane is more preferably a reaction product of a mixture containing a hydroxyl-terminated prepolymer, an isocyanate-terminated prepolymer, a conductive filler, and an additive.

[0201] When there are many hydroxyl groups, isocyanate groups, or urea bonds, allophanate bonds, isocyanurate bonds, etc., the polyurethane contains many polar functional groups, which increases the water absorption of the polymer and reduces the volume resistivity of the resin layer, potentially leading to charge leakage from the toner to the developing roller.On the other hand, by thermally curing the hydroxyl-terminated prepolymer and the isocyanate-terminated prepolymer, it is possible to obtain a polyurethane with little unreacted polyol or polar functional groups without using an excessive amount of isocyanate.

[0202] (A) Polyol compound The polyol compound may be any polyol known for or usable in the synthesis of urethane resins. Examples of polyol compounds include polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols such as polybutadiene polyols and polyisoprene polyols, so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols, and polyester-polycarbonate copolymer polyols.

[0203] Among these, polycarbonate polyols and polyester polycarbonate copolymer polyols are preferred. Examples of polycarbonate polyols include polynonamethylene carbonate diol, poly(2-methyl-octamethylene) carbonate diol, polyhexamethylene carbonate diol, polypentamethylene carbonate diol, poly(3-methylpentamethylene) carbonate diol, polytetramethylene carbonate diol, polytrimethylene carbonate diol, poly(1,4-cyclohexanedimethylene carbonate) diol, poly(2-ethyl-2-butyl-trimethylene) carbonate diol, and random / block copolymers thereof.

[0204] Examples of polyester polycarbonate copolymer polyols include the following: copolymers obtained by polycondensing the above-mentioned polycarbonate polyols with lactones such as ε-caprolactone, and copolymers of polyesters obtained by polycondensing diols such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, and neopentyl glycol with dicarboxylic acids such as adipic acid and sebacic acid.

[0205] (B) Polyisocyanate compound The polyisocyanate is selected from commonly used known ones, and examples thereof include: toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, hydrogenated MDI, polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. Among these, aromatic isocyanates such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymeric diphenylmethane polyisocyanate, and polymeric MDI are more preferably used. For other polyisocyanates, the impedance value and surface potential can be determined. Anything that does not affect the position can be used.

[0206] The ratio of the number of isocyanate groups to the number of hydroxyl groups (hereinafter also referred to as "NCO / OH ratio") is preferably 1.0 to 2.0. If this NCO / OH ratio is 1.0 to 2.0, the crosslinking reaction proceeds, and the bleeding of unreacted components and low-molecular-weight polyurethane, known as "bleeding," is suppressed. The NCO / OH ratio is more preferably 1.0 to 1.6. If this NCO / OH ratio is 1.0 to 1.6, bleeding is suppressed and the hardness of the polymer can be reduced.

[0207] The content of polyurethane in the resin layer is not particularly limited, but is preferably 50 to 95% by mass, more preferably 60 to 80% by mass, and even more preferably 65 to 75% by mass.

[0208] (additives) One preferred embodiment involves the use of an additive to further improve the dispersibility of carbon black in a binder resin using polycarbonate urethane. Here, for example, at least one compound selected from the group consisting of a compound having a structure represented by the following structural formula (V), a compound having a structure represented by the following structural formula (VI), and a compound having a structure represented by the following structural formula (VII) can be suitably used as the additive. One method for incorporating the additive into the surface layer is to incorporate a dispersant into a coating liquid for forming the surface layer (resin layer). Note that in a surface layer formed using a coating liquid for forming a surface layer containing at least one compound selected from the group consisting of a compound having a structure represented by structural formula (V) and a compound having a structure represented by structural formula (VI), the compound may be incorporated into the end of the polyurethane polymer chain. Even in such cases, the effect of improving the dispersibility of carbon black can be expected, but it is preferable that the additive be present in the surface layer independently of the polyurethane.

[0209] Among the compounds having the structures represented by structural formulas (V) to (VII), the compound having the structure represented by structural formula (V) is more preferably used because it has particularly excellent dispersibility of carbon black and affinity with polycarbonate urethane.

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] In structural formula (V), R19 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms (preferably 3 to 12). t and u represent the average number of moles added, and each independently represents a number of 1 or more (preferably 5 to 30, more preferably 10 to 25). In structural formula (VI), R20 represents a monovalent hydrocarbon group having 1 to 8 carbon atoms (preferably 1 to 4). v and w represent the average number of moles added, and each independently represents a number of 1 or more (preferably 1 to 30, more preferably 5 to 30). In structural formula (VII), R21 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. x represents the average number of moles added and is a number of 1 or more (preferably 1 to 30, more preferably 4 to 15).

[0214] Structural formula (V) is a polyoxyethylene polyoxypropylene alkyl ether, a polyether monool with a block-type addition polymerization structure of ethylene oxide and propylene oxide. The terminal hydroxyl groups of this polyether monool interact with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. Furthermore, the structure is compatible with polycarbonate urethane, enhancing its effectiveness as a dispersant for carbon black.

[0215] Ethylene oxide is introduced into the structure to ensure uniform distribution of the additive in the polycarbonate urethane. This is thought to be because the ethylene group in ethylene oxide is compatible with the hydrophobic hydrocarbon group in the polycarbonate urethane. Propylene oxide is introduced into the structure to improve the dispersibility of the conductive filler dispersed in the resin layer. This is thought to be because the side-chain methyl group of propylene oxide interacts with the conductive filler, improving the dispersibility of the conductive filler.

[0216] R19, ​​a monovalent hydrocarbon group having 1 to 12 carbon atoms, is introduced into the structure to allow the additive to be distributed uniformly throughout the polycarbonate urethane. Being a monovalent hydrocarbon group improves compatibility with the hydrophobic hydrocarbon groups in the polycarbonate urethane, allowing the additive to be distributed uniformly throughout the polycarbonate urethane. Having 12 or fewer carbon atoms reduces steric hindrance with the polycarbonate urethane, making it easier for the additive to be distributed uniformly. Furthermore, since the compound of formula (V) has a mono-ol structure, it has lower reactivity than a diol, and is less likely to be incorporated into the urethane reaction caused by the reaction of isocyanate with a polyol, and is less likely to introduce an ether structure into the polycarbonate urethane, which would reduce the resistance of the polyurethane.

[0217] The polyoxyethylene polyoxypropylene alkyl ether can be a commercially available product or can be obtained by synthesis. The synthesis of polyoxyethylene polyoxypropylene alkyl ether can be carried out by carrying out the following step (A) followed by step (B). Note that step (B) may also be carried out on a commercially available product whose structure has already been completed up to step (A).

[0218] Step (A): Reaction of alcohol with ethylene oxide Step (B): Reaction of the product obtained in step (A) with propylene oxide In step (A), the reaction can be carried out by adding ethylene oxide to an alcohol in the presence of a catalyst at 50 to 200°C, more preferably 100 to 160°C. The boiling point of ethylene oxide is 10.7°C, and it is in the form of a gas at the above temperature. The reaction is preferably carried out at a pressure of 0.1 to 1.0 MPa. The reaction time is not particularly limited, but is preferably about 1 to 3 hours in order to reduce the amount of unreacted ethylene oxide.

[0219] The catalyst may be an acid catalyst or an alkali catalyst, but an alkali catalyst is preferred to facilitate purification after the reaction. Examples of alkali catalysts include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide, ammonium hydroxide, and tertiary amines. In view of the ease and efficiency of the reaction, sodium hydroxide and potassium hydroxide are particularly preferred. Examples of acid catalysts include Bronsted acids such as sulfuric acid and phosphoric acid, and Lewis acids such as stannic chloride and boron trifluoride.

[0220] The amount of catalyst used is preferably 0.1 to 5 mol % per 1 mol of alcohol in the case of sodium hydroxide or potassium hydroxide. Since ethylene oxide reacts with water to produce ethylene glycol, it is important to prevent water from entering the reaction system as much as possible, and a dehydration treatment may be carried out before the reaction in step (A) as necessary.

[0221] Step (B) can be carried out under the same conditions as step (A). Propylene oxide has a boiling point of 34.2°C and is in a gaseous state at reaction temperatures of 50 to 200°C, so the reaction is preferably carried out in a pressurized environment in a sealed container. The catalyst used in step (A) may be used as is, or a new catalyst may be added. When a new catalyst is added, the catalyst used in step (A) is preferred.

[0222] Structural formula (VI) is a polyetheramine (monoamine) with a block-type addition polymerization structure of ethylene oxide and propylene oxide. The amino groups at the terminals of this polyetheramine interact with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. Furthermore, to enhance its effectiveness as a dispersant, R20, a monovalent hydrocarbon group with 1 to 8 carbon atoms, is introduced, resulting in a structure that is highly compatible with the hydrophobic functional groups of polycarbonate urethane, resulting in a structure that is also highly compatible with polycarbonate urethane. The polyether monoamine can be a commercially available product or can be obtained by synthesis. The synthesis of the polyether monoamine can be carried out by carrying out the following step (C) followed by step (D).

[0223] Step (C): Oxidation reaction of the compound of structural formula (V), which is a secondary alcohol Step (D): Reductive amination of the product obtained in step (C) Step (C) is the oxidation of a secondary alcohol to produce a ketone. The synthesis of ketones by oxidation of a secondary alcohol can be carried out using heavy metal salts such as chromic acid or manganese dioxide or their derivatives, or by non-heavy metal salt oxidation using dimethyl sulfoxide (DMSO) or hypohalous acids such as hypochlorous acid.

[0224] Although either method can be used for synthesis, oxidation reactions using hypohalous acids such as dimethyl sulfoxide (DMSO) or hypochlorous acid are preferred due to the environmental impact of heavy metals. Furthermore, dimethyl sulfoxide (DMSO) can undergo explosive reactions at room temperature depending on the electrophilic activating reagent used, requiring temperatures as low as -60°C, making the method using hypohalous acids more preferable. Examples of hypohalous acids include hypochlorites such as sodium hypochlorite and calcium hypochlorite (bleaching powder). Ketones can be obtained by reacting these hypochlorites with secondary alcohols in acetic acid.

[0225] When using dimethyl sulfoxide (DMSO), an additional electrophilic activating reagent is required. Electrophilic activating reagents increase the electrophilicity of the sulfur in dimethyl sulfoxide (DMSO), allowing it to undergo nucleophilic attack by the alcohol's hydroxyl group. This nucleophilic attack produces a dimethylalkoxysulfonium salt, which decomposes to yield a ketone and dimethyl sulfide. Electrophilic activating reagents include dicyclohexylcarbodiimide (DCC), acetic anhydride, phosphorus pentoxide, sulfur trisulfide-pyridine complex, trifluoroacetic anhydride, oxalyl chloride, and halogens.

[0226] Step (D) is a reductive amination reaction that converts a ketone to an amine. The reaction is divided into two steps. First, a carbonyl group reacts with an amine to generate an iminium cation. Next, a hydride reducing agent nucleophilically attacks the iminium cation to generate an amine. A borohydride reagent is preferably used as the reducing agent. Examples of borohydride reagents include sodium cyanoborohydride, sodium triacetoxyborohydride, and 2-picoline borane. Among these, sodium triacetoxyborohydride and 2-picoline borane are preferred due to their low toxicity. In the reductive amination reaction using a borohydride reagent, if the reagent has a bulky structure, steric hindrance makes it difficult to generate an iminium cation. Therefore, R20 in structural formula (VI) is preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms.

[0227] Structural formula (VII) is polyoxyethylene alkyl ether acetic acid. The terminal carboxylic acid in structural formula (VII) interacts with the surface functional groups of the conductive filler carbon black through hydrogen bonding, acting as a dispersant for the carbon black. Furthermore, to enhance its effectiveness as a dispersant, R21, a monovalent hydrocarbon group with 1 to 12 carbon atoms, is introduced, resulting in a structure that is highly compatible with the hydrophobic functional groups of polycarbonate urethane, resulting in a structure that is also highly compatible with polycarbonate urethane.

[0228] Polyoxyethylene alkyl ether acetic acid can be obtained by synthesis or commercially available products. Polyoxyethylene alkyl ether acetic acid can be synthesized by carrying out the following step (E) followed by step (F). Note that step (F) may also be carried out on a commercially available product whose structure has been completed up to step (E). Step (E): Reaction of alcohol with ethylene oxide Step (F): Oxidation reaction of the primary alcohol, which is the product of step (E) Step (E) is the same as step (A) and can be prepared by the same method as step (A).

[0229] Step (F) is the oxidation of a primary alcohol to produce a carboxylic acid. Because the oxidation of a primary alcohol produces an aldehyde, followed by further oxidation to produce a carboxylic acid, it is necessary to select a reaction method and conditions that do not stop at the aldehyde. Methods for obtaining a carboxylic acid by oxidation of a primary alcohol include oxidation with an oxidizing agent and catalytic dehydrogenation using a catalyst. Oxidizing agents include permanganate, chromic acid, ruthenium tetroxide, and hypochlorite. Dehydrogenation catalysts include palladium, platinum, iridium, rhodium, and manganese.

[0230] The compounds represented by structural formulas (V) to (VII) function as dispersants for carbon black and have high affinity with polycarbonate urethane. Surfactants are typically used to improve the dispersibility and dispersion stability of carbon black. However, the compounds represented by structural formulas (V) to (VII) have a small number of functional groups that interact with the surface functional groups of carbon black, resulting in weak surfactant properties and making them uncommonly used. Coupling agents and nonionic surfactants are commonly used as dispersants for carbon black.

[0231] Silane coupling agents, titanate coupling agents, and aluminum coupling agents are used as coupling agents, while polyester and polyether-based nonionic surfactants are used. However, adding these dispersants to polycarbonate urethane to a level that sufficiently enhances the dispersibility of carbon black (50 to 100% by mass relative to the carbon black) inhibits the conductivity of the carbon black and binder resin. Conversely, adding them in an amount that does not inhibit the conductivity of the carbon black and binder resin (10 to 40% by mass relative to the carbon black) does not result in sufficient dispersibility of the carbon black.

[0232] The amount of the compounds represented by structural formulas (V) to (VII) added is preferably 3.0 to 7.0 mass % based on the solid content in the coating material for forming a surface layer, more preferably 3.0 to 5.0 mass %, and the total content is preferably 18.9 to 46.0 mass parts relative to 100 mass parts of carbon black in the coating material for forming a surface layer. By ensuring that the content of the additive in the coating material for forming the surface layer is within the above range, the dispersibility of the carbon black in the polyurethane is further improved, and the desired impedance value and surface potential can be more easily achieved.

[0233] The presence of additives in the resin layer can be confirmed and quantitatively evaluated by the following method. The resin layer of the developing roller is cut out, and the cut piece is subjected to, for example, 1 H-NMR, 13 By using C-NMR, XPS, and FT-IR, it is possible to detect the carbonate structure of the binder resin, and the ether structure, amine structure, and carboxylic acid structure of the additive in the resin layer, and the ratio can be calculated from the peak ratio, etc. Alternatively, sections can be extracted by immersing them overnight in an organic solvent such as 2-butanone (methyl ethyl ketone; MEK), and the extract and the extracted sections can be analyzed. 1 H-NMR, 13 By using C-NMR, XPS, and FT-IR, it is possible to calculate the ratio of additives that are incorporated into the resin during the polymerization reaction and those that are not.

[0234] [Roughening particles] The resin layer may contain roughening particles. The roughening particles may be, for example, spherical particles. The particle diameter of the roughening particles is, for example, preferably in the range of 1 μm to 150 μm, and more preferably in the range of 5 μm to 30 μm. For example, at least one spherical particle selected from the following particles may be used. Urethane resin particles, acrylic resin particles, phenolic resin particles, silicone resin particles, polyacrylonitrile resin particles, polystyrene resin particles, polyurethane resin particles, nylon resin particles, polyethylene resin particles, polypropylene resin particles, preferably urethane resin particles. The content of the roughening particles in the resin layer is preferably 1 to 20% by mass, more preferably 5 to 15% by mass.

[0235] The developing roller may have an elastic layer on the outer surface of the substrate. The developing roller has the elastic layer between the substrate and the resin layer, for example. The elastic layer is not particularly limited, and any known elastic layer for developing rollers may be used. For example, a cured product of an addition-curing liquid silicone rubber mixture may be used.

[0236] (Manufacturing method) The method for forming the resin layer is not particularly limited, but examples thereof include spraying with a paint, dip coating, and roll coating. For example, a resin layer can be formed by applying a resin layer-forming coating liquid to the substrate or an elastic layer formed on the outer surface of the substrate using a known method, and then drying by heating. The conditions for drying by heating are not particularly limited, and examples thereof include a method of drying at a temperature of 120 to 200°C. The thickness of the resin layer is also not particularly limited, and is preferably 1 to 50 μm. More preferably, it is 5 to 20 μm.

[0237] <Process cartridge and electrophotographic image forming apparatus> The developer carrier according to the present disclosure can be suitably used as a developer carrier (e.g., a developing roller) in a process cartridge. The process cartridge includes the developing device according to the present disclosure. FIG. 3 is a schematic cross-sectional view of an example of a process cartridge according to one embodiment of the present disclosure. The process cartridge 22 is configured to be detachably attachable to the main body of an electrophotographic image forming apparatus. The process cartridge 22 integrates a developing device 18 including a developing roller 14 and a developing blade 15, a photoreceptor 19, a charging roller 20, and a cleaning blade 21. The developing device 18 is further filled with toner 16. The toner 16 is supplied to the surface of the developing roller 14 by a toner supply roller 17, and a layer of toner 16 of a predetermined thickness is formed on the surface of the developing roller 14 by the developing blade 15.

[0238] The developing roller 14 is in contact with the photosensitive member 19 and is driven to rotate at a predetermined peripheral speed ratio relative to the photosensitive member 19. A predetermined bias is applied to the developing roller 14, and the electrostatic latent image on the photosensitive member 19 is developed with the toner 16 to be visualized.

[0239] The toner supply roller 17 comes into contact with the developing roller 14, penetrates a predetermined amount, and rotates in the same direction as or opposite to the rotation direction of the developing roller 14. A predetermined bias is applied to the toner supply roller 17.

[0240] One end of the developing blade 15 is fixed to the developing device 18, and the other free end is arranged in contact with the developing roller 14 in the counter direction to the rotational direction. By arranging the developing blade 15 in contact with the developing roller 14, the amount of toner on the developing roller 14 is regulated, making the layer thinner and forming a toner layer of uniform thickness. In addition, a predetermined bias is applied to the developing blade 15, imparting an electric charge to the toner 16.

[0241] The developing device has a developer and a developer carrier for carrying the developer. The developing device also has a developer layer thickness regulating member (e.g., a developing blade 15) that contacts the developer carrier (e.g., a developing roller 14) and regulates the layer thickness of the developer (e.g., toner 16) carried on the developer carrier, and a contact point electrically connected to the developer layer thickness regulating member. When the developing device is mounted in the main body of an electrophotographic device, the contact point electrically connects to the main body contact point of the main body of the electrophotographic device, enabling a predetermined voltage to be applied to the developer layer thickness regulating member. The volume resistivity of the developer layer thickness regulating member is 1.0×10 6 It is preferable that the resistivity is Ω·cm or less. This allows the developer layer thickness regulating member to form a developer layer of uniform thickness on the developer carrier, and at the same time, makes it possible for the developer layer thickness regulating member to inject charge into the developer, making it easy to uniformly control the toner charge amount.

[0242] The electrophotographic image forming apparatus includes the developing device of the present disclosure. FIG. 4 is a schematic cross-sectional view showing an example of an electrophotographic image forming apparatus equipped with a contact-type developing device using one-component toner. The developing device 18 includes toner 16 as one-component toner, a developing roller 14, a toner supply roller 17 that supplies toner to the developing roller 14, and a developing blade 15 that regulates the thickness of the toner layer on the developing roller 14. The developing roller 14 is located in an opening extending in the longitudinal direction of the developing device 18 and is installed in contact with the photoreceptor 19. Note that the photoreceptor 19, charging roller 20, and cleaning blade 21 may be provided in the main body of the electrophotographic image forming apparatus. The developing device 18 is equipped with black, cyan, magenta, and yellow toners, enabling color printing.

[0243] An image can be formed using the developing device of the present disclosure. The image forming method according to the present disclosure includes a developing step of developing an electrostatic latent image on an image carrier with toner. The method includes a transfer step in which the image developed in the development step is transferred to a transfer-receiving material with or without an intermediate transfer body, and a fixing step in which the image transferred onto the transfer-receiving material is fixed to the transfer-receiving material.

[0244] The printing operation of an electrophotographic image forming apparatus equipped with the developing device of the present disclosure will be described below. The photoconductor 19 rotates in the direction of the arrow and is uniformly charged by a charging roller 20 that charges the photoconductor 19. Next, an electrostatic latent image is formed on the surface of the photoconductor 19 by a laser beam 23, which serves as an exposure means. The electrostatic latent image is visualized as a toner image (developed) by the developing device 18, which applies toner 16 from a developing roller 14 that is placed in contact with the photoconductor 19. The development is what is known as reversal development, in which a toner image is formed in the exposed area.

[0245] The toner image formed on the photosensitive member 19 is transferred onto an intermediate transfer member 25 in the form of an endless belt by a transfer roller 24 which is a transfer member. Paper 26, which is a recording medium, is fed into the device by paper feed roller 27 and secondary transfer roller 28, and is transported together with intermediate transfer body 25 bearing a toner image to the nip between secondary transfer roller 28 and driven roller 29, where the toner image is transferred to paper 26. Intermediate transfer body 25 is operated by driven roller 29, drive roller 30, and tension roller 31. Toner remaining on intermediate transfer body 25 is cleaned by cleaning device 32. The image may be transferred directly from the photosensitive drum to the recording material without using an intermediate transfer member.

[0246] A voltage is applied to the developing roller 14, developing blade 15, transfer roller 24, and secondary transfer roller 28 from a bias power supply 33. The paper 26 onto which the toner image has been transferred is fixed by a fixing device 34 and then ejected outside the device, completing the printing operation. Meanwhile, residual toner remaining on the photoreceptor 19 without being transferred is scraped off by a cleaning blade 21, which is a cleaning member for cleaning the surface of the photoreceptor. The cleaned photoreceptor 19 repeats the above printing operation.

[0247] The methods for measuring the physical properties of the developing roller and each material will be described below. <Calculation of the equivalent circle diameter and wall distance of carbon black dispersed in a resin layer> The particle size of the carbon black dispersed in the resin layer and the wall-to-wall distance are measured by the following method. First, a piece (0.5 to 1.0 mm thick) of the developing roller is cut out using a razor.

[0248] Next, the slice is platinum-deposited, and the resin layer is photographed at 15,000x magnification using a scanning electron microscope (SEM) (trade name: JSM-7800F, manufactured by JEOL Ltd.) to obtain an image of the resin layer surface. Furthermore, to quantify the images obtained by SEM observation, the images were processed using image processing software (trade name: Luzex AP, manufactured by Nireco Corporation) to convert the images into 8-bit grayscale images. The image is then rescaled to obtain a monochrome image with 256 gradations. Next, the image is inverted so that the carbon black in the image appears white, and a binarization threshold is set for the brightness distribution of the image based on the algorithm of Otsu's discriminant analysis method, resulting in a binarized image in which the carbon black appears white and the binder resin appears black.

[0249] The resulting binarized image was then processed using image processing software (product name: Luzex AP, Using a microscope (manufactured by Nireco Corporation), calculate the equivalent circle diameter of the white carbon black area and the distance between adjacent walls. In order to eliminate the uncertainty of the calculated values ​​for the carbon black that is divided at the top, bottom, left, and right edges of the image, the image area is set to an area 0.075 μm inside in actual image dimensions (if there is a text section describing the SEM measurement conditions, etc., 0.075 μm inside from the beginning of the actual image), and calculate the equivalent circle diameter and distance between adjacent walls for all carbon black within the specified image area. Calculate the distance. Then, the arithmetic mean value and standard deviation are calculated for the distribution of the obtained circle equivalent diameter and the distance between adjacent wall surfaces. In order to eliminate the influence of differences in the longitudinal direction of the conductive fine particles dispersed in the resin layer of the developing roller, the developing roller was divided into 10 equal sections in the longitudinal direction, and the arithmetic mean of the circle-equivalent diameters and the distances between adjacent wall surfaces of the 10 sections was used as the circle-equivalent diameter and the distances between adjacent wall surfaces in the present disclosure.

[0250] (Measurement of DBP absorption amount of carbon black) The DBP absorption amount of carbon black is a value measured for carbon black powder in accordance with Japanese Industrial Standards (JIS) K6217-4.

[0251] (Measurement of pH of carbon black) The pH of carbon black is the value measured for carbon black powder in accordance with ASTM D1512. [Example]

[0252] The present disclosure will be described in more detail below with reference to examples, but these examples are not intended to limit the present disclosure in any way. Hereinafter, "parts" refers to "parts by mass" unless otherwise specified.

[0253] [Toner manufacturing example] <Production Example of Block Copolymer Composition> A pressure-resistant reactor was charged with 23.2 kg of cyclohexane, 1.5 mmol of N,N,N',N'-tetramethylethylenediamine (hereinafter referred to as TMEDA), and 1.70 kg of styrene, and the mixture was stirred at 40°C. 99.1 mmol of n-butyllithium was added, and the mixture was polymerized for 1 hour while the temperature was raised to 50°C. The polymerization conversion of styrene was 100%. Subsequently, 6.03 kg of isoprene was continuously added to the reactor over 1 hour while controlling the temperature to maintain a temperature of 50-60°C.

[0254] After the addition of isoprene was completed, polymerization was continued for another hour to form styrene-isoprene diblock copolymer B (a copolymer represented by Ar-D). The polymerization conversion rate of isoprene was 100%. Next, 15.0 mmol of dimethyldichlorosilane was added as a coupling agent, and a coupling reaction was carried out for 2 hours to form a styrene-isoprene-styrene triblock copolymer (a copolymer represented by Ar-D-Ar).

[0255] After this, 198 mmol of methanol was added as a polymerization terminator and mixed thoroughly to terminate the reaction, yielding a reaction solution containing a block copolymer composition. A portion of the resulting reaction solution was removed, and the weight-average molecular weight, content ratio, and vinyl bond content of each block copolymer and the entire block copolymer composition were determined. The results are shown in Table 1.

[0256] Then, 0.3 parts of 2,6-di-tert-butyl-p-cresol was added as an antioxidant to 100 parts of the reaction liquid obtained in this manner (containing 30 parts of the polymer component) and mixed. This mixed solution was added dropwise in small amounts to warm water heated to 85 to 95°C to volatilize the solvent, obtaining a precipitate. This precipitate was then pulverized and dried with hot air at 85°C to recover a block copolymer composition. The melt index of the obtained block copolymer composition was measured. The results are shown in Table 1.

[0257] [Table 1]

[0258] <Method of manufacturing toner 1> Polymerizable monomer: 74 parts styrene, 26 parts n-butyl acrylate Colorant: Carbon black (Mitsubishi Chemical, product name: #25B) 7 parts Crosslinking agent: Divinylbenzene 0.74 parts Charge control agent: styrene / acrylic resin (manufactured by Fujikura Kasei Co., Ltd., product name: FCA-592P) 0.37 parts Molecular weight regulator: 1 part tetraethyl thiuram disulfide Macromonomer: Polymethacrylate macromonomer (manufactured by Toagosei Chemical Industry Co., Ltd., trade name: AA6, Tg = 94°C) 0.25 parts Block copolymer composition 5 parts The above materials were stirred and mixed with a stirring device, then uniformly dispersed with a media-type disperser, and heated to 63°C. Here, the ester compound (R 11 =-C 21 H43 20 parts of 1,2-dimethyl-2,4-diol (diethylamino)propan ...

[0259] On the other hand, in a stirring tank at room temperature, an aqueous solution prepared by dissolving 7.4 parts of magnesium chloride in 250 parts of ion-exchanged water was gradually added with stirring to prepare a magnesium hydroxide colloidal dispersion (3.0 parts of magnesium hydroxide).

[0260] 100 parts of the polymerizable monomer composition was added to the magnesium hydroxide colloidal dispersion obtained above at room temperature, the temperature was raised to 60°C, and the mixture was stirred until the droplets stabilized. Five parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: Perbutyl O) was added as a polymerization initiator, and then the mixture was stirred with high shear at a rotation speed of 15,000 rpm using an in-line emulsifying disperser (manufactured by Pacific Machinery Works, trade name: Milder) to form droplets of the polymerizable monomer composition.

[0261] The magnesium hydroxide colloidal dispersion in which droplets of the polymerizable monomer composition were dispersed was placed in a reactor equipped with a stirring blade, heated to 89°C, and controlled to maintain a constant temperature, to carry out a polymerization reaction. Next, when the polymerization conversion rate reached 98%, the temperature in the system was cooled to 75°C, and 15 minutes after reaching 75°C, 2,2'-azobis[2-methyl-N-(1,1-bis(hydroxymethyl)2-hydroxyethyl)propionamide] tetrahydrate (Wako Pure Chemical Industries, Ltd.) dissolved in 2 parts of methyl methacrylate as a shell polymerizable monomer and 10 parts of ion-exchanged water was added. Then, 0.36 parts of a product manufactured by Yaku Co., Ltd. (trade name: VA086) was added. After continuing the polymerization for another 3 hours, the reaction was stopped to obtain an aqueous dispersion of colored resin particles with a pH of 9.5.

[0262] After this, the aqueous dispersion of colored resin particles was heated to 80°C and passed through a nitrogen gas flow rate of 0.6 m 3After a 5-hour stripping treatment at 1000 kJ / (hr·kg), the suspension was cooled from 80°C to 25°C at a rate of 3.5°C / sec. The resulting aqueous dispersion was then cooled at 25°C with sulfuric acid at a pH of 6.5 or less, and acid washed. After filtering, the water was removed, and 500 parts of ion-exchanged water was added to re-slurry the suspension, followed by water washing. The dehydration and water washing were repeated several times, and the solids were filtered and separated. The suspension was then placed in a dryer and dried at 40°C for 12 hours to obtain toner particles 1.

[0263] To the toner particles 1 (100 parts) obtained above, 0.7 parts of hydrophobicized silica fine particles having a number average particle size of 7 nm and 1 part of hydrophobicized silica fine particles having a number average particle size of 50 nm were added and mixed using a high-speed mixer (manufactured by Nippon Coke & Engineering Co., Ltd., product name: FM Mixer) to produce toner 1. The physical properties of the obtained toner 1 are shown in Table 2.

[0264] [Table 2-1] [Table 2-2]

[0265] <Manufacturing Method of Toners 2 to 5 and 8 to 20> Toners 2 to 5 and 8 to 20 were obtained in the same manner as in the production example of Toner 1, except that the type and amount of the ester compound, and the amounts of the block copolymer composition, sodium hydroxide for the colloidal dispersion, and methyl methacrylate, which is a polymerizable monomer for the shell, were changed as shown in Table 2. The physical properties of the obtained Toners 2 to 5 and 8 to 20 are shown in Table 2.

[0266] <Method of manufacturing toner 6> Toner 6 was obtained in the same manner as in the production method of Toner 1, except that in the cooling step in the production method of Toner 1, water at 15°C was added to the suspension and the suspension was cooled from 80°C to 25°C at a rate of 1.5°C / sec. The physical properties of the obtained Toner 6 are shown in Table 2.

[0267] <Method of manufacturing toner 7> Toner 7 was obtained in the same manner as in the method for producing toner 1, except that in the cooling step in the method for producing toner 1, the suspension was naturally cooled to 25° C. at room temperature. The physical properties of the obtained toner 7 are shown in Table 2.

[0268] <Toner 21 Manufacturing Method> In the method for producing toner 1, the step of adding a polymerizable monomer for shell is not carried out after the polymerization reaction step. First, the aqueous dispersion of colored resin particles was cooled to 80° C., and thereafter, the same production method as for Toner 1 was carried out to obtain Toner 21. The physical properties of Toner 21 obtained are shown in Table 2.

[0269] <Developing roller manufacturing example> In this embodiment, a developing roller in which a resin layer is coated on an elastic roller having an elastic layer on the outer surface of a base body will be described, but the invention is not limited to this configuration.

[0270] [Preparation and manufacturing of raw materials for forming resin layer] <Preparation of raw polyol and manufacturing example> A synthesis example for obtaining a polyurethane resin layer will be shown below.

[0271] [Measurement of number average molecular weight of raw material polyol] The apparatus and conditions used for measuring the number average molecular weight (Mn) in this production example are as follows.

[0272] Measuring device: HLC-8120GPC (Tosoh Corporation) Column: TSKgel Super HZMM (Tosoh Corporation) x 2 Solvent: tetrahydrofuran (THF) (20 mmol / L triethylamine added) Temperature: 40℃ THF flow rate: 0.6 mL / min The measurement sample was a 0.1% by mass THF solution. Furthermore, the measurement was carried out using an RI (refractive index) detector as the detector. A calibration curve was created using TSK standard polystyrenes A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, and F-128 manufactured by Tosoh Corporation as standard samples. Based on this calibration curve, the number average molecular weight was calculated from the retention time of the obtained measurement sample.

[0273] [Preparing raw polyol] The two raw material polyols A-1 and A-2 were commercially available products shown in Table 3 below.

[0274] [Table 3]

[0275] <Preparing raw material isocyanates B-1 and B-2> The raw material isocyanates shown in Table 4 below were prepared.

[0276] [Table 4]

[0277] <Production Example of Hydroxyl-Terminated Urethane Prepolymer> [Synthesis of hydroxyl-terminated urethane prepolymer] Under a nitrogen atmosphere, 100 parts by mass of raw material polyol A-1 and 6.3 parts by mass of raw material isocyanate B-1 were reacted by heating and stirring at a temperature of 90°C for 3 hours. 2-Butanone (MEK) was then added to the resulting reaction product to prepare a solution with a solid content of 50 parts by mass, thereby producing a hydroxyl group-terminated urethane prepolymer.

[0278] The chemical structure of the hydroxyl-terminated urethane prepolymer is 1 H-NMR and 13This hydroxyl-terminated urethane prepolymer was characterized using C-NMR. The molecule contained the structure represented by the following structural formula (I), where R13 = (CH2)5, R14 = (CH2)6, R15 = (CH2)6, m = 6, and n = 9.

[0279] [ka]

[0280] <Production Example of Isocyanate-Terminated Prepolymer> [Synthesis of isocyanate-terminated prepolymer] Under a nitrogen atmosphere, 100 parts by mass of raw material polyol A-2 and 33.5 parts by mass of raw material isocyanate B-2 were reacted by heating and stirring at a temperature of 90°C for 3 hours. Then, 2-butanone (MEK) was added to the resulting reaction product to prepare a solution with a solid content of 50 parts by mass, producing an isocyanate-terminated prepolymer. The chemical structure of the isocyanate-terminated prepolymer is 1 H-NMR and 13 This isocyanate-terminated prepolymer was characterized using C-NMR. The molecule contained a structure represented by the following structural formula (IV), where R18 = (CH2)6 and s = 13.2.

[0281] [ka]

[0282] [Preparation and manufacturing of resin layer additive raw materials] <Preparation of polyoxyethylene polyoxypropylene alkyl ether> As the additive, commercially available polyoxyethylene polyoxypropylene butyl ether (trade name: Uniloop 50MB-26, manufactured by NOF Corporation) was used.

[0283] [Production examples of resin layer forming coating solutions C-1 to C-13] <Preparation of Coating Solution C-1 for Forming Resin Layer> The materials for resin layer-forming coating solution C-1, the types and amounts of which are listed in Table 5 below, were added to a reaction vessel and stirred. Next, 2-butanone (MEK) was added so that the total solids ratio was 30% by mass, and the mixture was mixed using a sand mill. Next, 2-butanone (MEK) was added to adjust the viscosity of the solution to within the range of 6 to 10 mPa·s, thereby producing resin layer-forming coating solution C-1.

[0284] [Table 5]

[0285] <Preparation of Resin Layer Forming Coating Solutions C-2 to C-13> As shown in Table 6, resin layer forming coating solutions C-2 to C-13 were prepared in the same manner as in the production example for resin layer forming coating solution C-1, except that the type and amount of carbon black added were changed.

[0286] [Table 6]

[0287] [Manufacturing example of developing rollers D-1 to D-13] <Preparation of the substrate> As a substrate, a 6 mm diameter core bar made of stainless steel (SUS304) was prepared by applying a primer (product name: DY35-051, manufactured by Dow Toray Industries, Inc.) to the circumferential surface and baking it.

[0288] <Preparation of Elastic Layer> The substrate was placed in a mold, and an addition-type silicone rubber composition prepared by mixing the materials shown in Table 7 was poured into the cavity formed in the mold.

[0289] [Table 7]

[0290] Next, the mold was heated to vulcanize and harden the silicone rubber at 150°C for 15 minutes, and after demolding, it was further heated at 180°C for 1 hour to complete the hardening reaction, resulting in an elastic roller with an elastic layer with a diameter of 11.5 mm on the outer periphery of the base body.

[0291] <Preparation of Resin Layer> The elastic roller was oriented with its longitudinal direction in the vertical direction, and its upper end was gripped and immersed (dipped) in the resin layer-forming coating solution C-1 to coat the surface of the elastic roller with the coating solution. The resulting coating was air-dried at room temperature for 30 minutes and then dried for 1 hour in a hot air circulating dryer set at 160°C. In this way, developing roller D-1 was obtained, with a 12 μm-thick resin layer formed on the elastic layer. The physical properties and dispersion state of the carbon black in the resulting developing roller are shown in Table 8.

[0292] [Table 8] In the table, "D roller" means "developing roller."

[0293] <Manufacturing Examples of Developing Rollers D-2 to D-13> Developing rollers D-2 to D-13 were produced in the same manner as in the production example for developing roller D-1, except that the resin layer-forming coating liquids were changed to C-2 to C-13 as shown in Table 8. Table 8 also shows the physical properties and dispersion state of the carbon black in the resulting developing rollers.

[0294] <Examples 1 to 18> Using the above toners 1 to 18 and developing rollers D-1 to D-10, the combinations shown in Table 9 were obtained. The evaluation results are shown in Table 9.

[0295] <Comparative Examples 1 to 6> Using the above toners 1, 19 to 21 and developing rollers D-1, D-11 to D-13, various evaluations were carried out in the combinations shown in Table 9. Table 9 shows the evaluation results.

[0296] [Table 9]

[0297] The evaluation methods and evaluation criteria of the present disclosure will be described below. <Evaluation of white spots due to development> The evaluation of whiteout was carried out using a commercially available non-magnetic single-component development printer (Brother Industries, product name: MFC-9840-CDW) on Fox River Bond (90 g / m 2 In addition, in the combinations of toner and developing roller shown in Table 9, the developing roller and toner were replaced with each developing roller and toner to be evaluated. First, a test was conducted in a normal temperature and humidity (N / N) environment (23°C, 60% RH) to print 1.5% horizontal lines in a single sheet intermittent mode for three days, printing 15,000 sheets (5,000 sheets per day).

[0298] At the end of the third day of use (after printing 15,000 sheets), one halftone image and one solid black image were printed, and if the density of the resulting image was 0.3 or more lower than the density of the image printed at the beginning of use (the 10th sheet), it was considered to have whiteout. The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth). Whiteout was evaluated according to the following criteria. A: No white areas B: The density is slightly low in the latter half of the image, but no white spots occur. C: A small white area (less than 1.0 cm wide) is visible in the latter half of the image. D: White spots are seen in the latter half of the image

[0299] <Evaluation of low-temperature fixability> The evaluation of low-temperature fixability was carried out in a room temperature and humidity environment (temperature 25.0°C, relative humidity 60%) using a commercially available non-magnetic single-component development printer (Brother Industries, Ltd., product name: MFC-9840-CDW). The image forming apparatus was modified so that the fixing temperature of the fixing unit could be set as desired. The developing rollers and toners were replaced with the developing rollers and toners to be evaluated using the toner and developing roller combinations shown in Table 9.

[0300] Using this device, the fixing temperature of the fixing unit was adjusted in 5°C increments within the range of 180°C to 230°C, and rough paper, FOX RIVER BOND paper (90 g / m 2 ) and print ratio Five 100% solid black images were printed in succession, and the fifth solid image was visually inspected for the presence or absence of white spots. The lowest temperature at which white spots appeared was used to evaluate the low-temperature fixability.

[0301] A: No white spots occurred at 180°C, or white spots occurred at less than 200°C. B: White spots occurred at temperatures between 200°C and 210°C. C: White spots occurred at temperatures between 210°C and 220°C. D: White spots occurred at 220°C or higher.

[0302] <Evaluation 4: Evaluation of storage stability> The storage stability was evaluated using a commercially available non-magnetic single-component development printer (Brother Industries, Ltd., product name: MFC-9840-CDW). In addition, the developing roller and toner in the combination of toner and developing roller shown in Table 9 were replaced with each developing roller and toner to be evaluated. First, one solid image was printed in a normal temperature and humidity environment (temperature 25.0°C, relative humidity 60%), and then the developing device was stored in a harsh environment (temperature 40.0°C, relative humidity 95%) for 40 days. After storage, one solid image was printed in a normal temperature and humidity environment (temperature 25.0°C, relative humidity 60%), and the image density before and after storage was compared and evaluated. The density of the solid image was measured using a Macbeth reflection densitometer (manufactured by Macbeth).

[0303] A: The density difference is less than 0.05 B: Density difference is 0.05 or more and less than 0.10 C: Density difference is 0.10 or more and less than 0.20 D: Density difference is 0.20 or more

[0304] The present disclosure relates to the following configurations. (Configuration 1) A developing device having a developer and a developer carrier for carrying the developer, the developer includes a toner having toner particles containing a binder resin; the toner particles have a core-shell structure having a core containing an ester compound and a shell formed on the surface of the core, The ester compound contains at least one ester compound selected from the group represented by the following formulas (1) to (7): The shell contains a compound having a structure represented by the following formula (8): the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate, the resin layer contains carbon black, the arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is 80.0 nm or less; the arithmetic mean value d of the distance between the wall surfaces of the carbon black in the resin layer is 60.0 to 170.0 nm; A developing device characterized by: [ka] In formulas (1) to (8), each independently represents R 1 , R 2 , R 9 , R 10 is a linear alkyl group having 16 to 22 carbon atoms, R 3 , R 5 , R 6 , R 8 , R 11 , R 12 is a linear alkyl group having 14 to 22 carbon atoms, R 4 , R 7 is a linear alkylene group having 1 to 6 carbon atoms, R 14 represents a linear alkyl group having 1 to 3 carbon atoms. (Configuration 2) 2. The developing device according to configuration 1, wherein Rc is 70.0 nm or less. (Configuration 3) 3. The developing device according to configuration 1 or 2, wherein d is 70.0 to 160.0 nm. (Configuration 4) 4. The developing device according to any one of configurations 1 to 3, wherein the Rc is 60.0 nm or less. (Configuration 5) 5. The developing device according to any one of configurations 1 to 4, wherein d is 80.0 to 150.0 nm. (Configuration 6) The developing device according to any one of configurations 1 to 5, wherein the secondary ion intensity at the surface of the toner and at a depth of 30 nm is measured by time-of-flight secondary ion mass spectrometry, and the secondary ion intensity corresponding to the structure expressed by formula (8) at a depth of 30 nm from the toner surface is divided by the sum of all secondary ion intensities at a depth of 30 nm from the toner surface, and the secondary ion intensity corresponding to the structure expressed by formula (8) at the toner surface is divided by the sum of all secondary ion intensities at the toner surface, and the value A(30) is defined as A(0), and the secondary ion intensity corresponding to the structure expressed by formula (8) at the toner surface is divided by the sum of all secondary ion intensities at the toner surface, and the values ​​A(0) and A(30) satisfy the relationships of the following formulas (9) and (10). 3.0≦A(0) / A(30)≦10.0 (9) 0.001≦A(30) (10) (Configuration 7) the toner contains an aromatic vinyl-based thermoplastic elastomer, 7. The developing device according to any one of configurations 1 to 6, wherein the aromatic vinyl thermoplastic elastomer is a diblock copolymer consisting of an aromatic vinyl polymer block and a block of a polymer copolymerizable with the aromatic vinyl polymer. (Configuration 8) 8. The developing device according to claim 7, wherein the polymer copolymerizable with the aromatic vinyl polymer is a conjugated diene polymer. (Configuration 9) 9. The developing device according to any one of configurations 1 to 8, wherein the shell contains polymethyl methacrylate. (Configuration 10) 10. The developing device according to any one of configurations 1 to 9, wherein when a cross section of the toner is observed with a scanning transmission electron microscope (STEM), the number average major axis of the ester compound is 300 nm or less. (Configuration 11) 11. The developing device according to any one of configurations 1 to 10, wherein the relationship between the volume average particle diameter Dv of the toner and the d satisfies the following formula (11). 50.0≦Dv / d≦100.0 (11) (Configuration 12) An image forming method, comprising: a developing step of developing an electrostatic latent image on an image carrier with toner using the developing device according to any one of configurations 1 to 11; a transfer step of transferring the image developed in the development step to a transfer-receiving material with or without an intermediate transfer body; and a fixing step of fixing the image transferred onto the transfer material; An image forming method comprising the steps of: (Configuration 13) A process cartridge configured to be detachably mounted in a main body of an electrophotographic image forming apparatus, 12. A process cartridge comprising the developing device according to any one of aspects 1 to 11. (Configuration 14) An electrophotographic image forming apparatus, 12. An electrophotographic image forming apparatus comprising the developing device according to any one of Configurations 1 to 11.

Claims

1. A developing device having a developer and a developer carrier for carrying the developer, the developer includes a toner having toner particles containing a binder resin, the toner particles have a core-shell structure having a core containing an ester compound and a shell formed on the surface of the core, The ester compound contains at least one ester compound selected from the group represented by the following formulas (1) to (7): The shell contains a compound having a structure represented by the following formula (8): the developer carrier has a substrate having a conductive outer surface and a resin layer on the outer surface side of the substrate, the resin layer contains carbon black, the arithmetic mean value Rc of the equivalent circle diameter of the carbon black in the resin layer is 80.0 nm or less; the arithmetic mean value d of the distance between wall surfaces of the carbon black in the resin layer is 60.0 to 170.0 nm; A developing device characterized by: In formulas (1) to (8), each independently represents R １ , R ２ , R ９ , R １０ is a linear alkyl group having 16 to 22 carbon atoms, R ３ , R ５ , R ６ , R ８ , R １１ , R １２ is a linear alkyl group having 14 to 22 carbon atoms, R ４ , R ７ is a linear alkylene group having 1 to 6 carbon atoms, R １４ represents a linear alkyl group having 1 to 3 carbon atoms.

2. 2. The developing device according to claim 1, wherein the Rc is 70.0 nm or less.

3. 2. The developing device according to claim 1, wherein d is 70.0 to 160.0 nm.

4. 2. The developing device according to claim 1, wherein the Rc is 60.0 nm or less.

5. 2. The developing device according to claim 1, wherein d is 80.0 to 150.0 nm.

6. 2. The developing device according to claim 1, wherein the secondary ion intensities at the surface of the toner and at a depth of 30 nm are measured by time-of-flight secondary ion mass spectrometry, and when the secondary ion intensity corresponding to the structure expressed by formula (8) at a depth of 30 nm from the toner surface is divided by the sum of all secondary ion intensities at a depth of 30 nm from the toner surface to give A(30), and the secondary ion intensity corresponding to the structure expressed by formula (8) at the toner surface is divided by the sum of all secondary ion intensities at the toner surface to give A(0), A(0) and A(30) satisfy the relationships of the following formulas (9) and (10): 3.0≦A(0) / A(30)≦10.0 (9) 0.001≦A(30) ... (10)

7. the toner contains an aromatic vinyl-based thermoplastic elastomer, 2. The developing device according to claim 1, wherein the aromatic vinyl thermoplastic elastomer is a diblock copolymer comprising an aromatic vinyl polymer block and a polymer block copolymerizable with the aromatic vinyl polymer.

8. 8. The developing device according to claim 7, wherein the polymer copolymerizable with the aromatic vinyl polymer is a conjugated diene polymer.

9. 10. The development system of claim 1, wherein said shell comprises polymethyl methacrylate.

10. 2. The developing device according to claim 1, wherein when a cross section of the toner is observed with a scanning transmission electron microscope (STEM), the number average major axis of the ester compound is 300 nm or less.

11. 2. The developing device according to claim 1, wherein the relationship between the volume average particle diameter Dv of the toner and the d satisfies the following formula (11): 50.0≦Dv / d≦100.0 (11)

12. An image forming method, comprising: a developing step of developing an electrostatic latent image on an image carrier with toner using the developing device according to any one of claims 1 to 11; a transfer step of transferring the image developed in the development step to a transfer-receiving material with or without an intermediate transfer body; and a fixing step of fixing the image transferred onto the transfer material; An image forming method comprising the steps of:

13. A process cartridge configured to be detachably mounted in a main body of an electrophotographic image forming apparatus, 12. A process cartridge comprising the developing device according to claim 1.

14. An electrophotographic image forming apparatus, 12. An electrophotographic image forming apparatus comprising the developing device according to claim 1.

Images