Static charge image developer and process cartridge

Abstract

The present invention provides an electrostatic charge image developer and a processing cartridge for suppressing a density difference occurring between images having different image forming speeds. An electrostatic charge image developer includes: toner containing toner particles, the toner particles containing a binder resin, a release agent, and a nonionic surfactant; and a resin-coated carrier having magnetic particles and a resin layer coating the magnetic particles, with a true specific gravity of 3 g / cm<supgt;3< / supgt> or more and 4 g / cm<supgt;3< / supgt> or less.

Description

Technical Field

[0001] The present invention relates to a charge image developer and a processing cartridge. Background Art

[0002] Patent Document 1 discloses a method for manufacturing an electrophotographic toner, which includes a step of generating primary particles containing a binder resin and a colorant in an aqueous medium in the presence of a nonionic surfactant, and a step of aggregating and uniting the primary particles.

[0003] Patent Document 2 discloses a method for manufacturing an electrophotographic toner, which includes a step of adjusting the pH value of an aqueous mixture containing aggregated particles including resin particles and release agent particles and a nonionic surfactant to 2.5 to 5.5 at 25°C and / or while adjusting, and fusing the aggregated particles in the aqueous mixture.

[0004] Patent Document 3 discloses a charge image developing toner, which contains a surfactant, a binder resin, and wax, and contains a nonionic surfactant having a hydrophilic-lipophilic balance (HLB) value of less than 5 as the surfactant.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2006-171692

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2012-233982

[0009] Patent Document 3: Japanese Patent Laid-Open No. 2010-156967 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] The subject of the present disclosure is to provide a charge image developer including: toner including toner particles containing a binder resin, a release agent, and a nonionic surfactant; and a resin-coated carrier having magnetic particles and a resin layer coating the magnetic particles, and the charge image developer suppresses a density difference occurring between images with different image formation speeds compared to a charge image developer having a true specific gravity of more than 4 g / cm 3 .

[0012] Means for Solving the Problems

[0013] Specific means for solving the above problems include the following embodiments.

[0014] <1> A static charge image developer, comprising: toner containing toner particles, the toner particles containing a binder resin, a release agent, and a nonionic surfactant; and a resin-coated carrier having magnetic particles and a resin layer coating the magnetic particles, with a true specific gravity of 3 g / cm 3 or more and 4 g / cm 3 or less.

[0015] <2> The static charge image developer according to <1>, wherein the binder resin contains an amorphous modified polyester resin obtained by modifying an amorphous polyester resin with at least one of styrene and (meth)acrylate.

[0016] <3> The static charge image developer according to <1> or <2>, wherein the binder resin contains at least one of a crystalline polyester resin and a crystalline modified polyester resin obtained by modifying a crystalline polyester resin with at least one of styrene and (meth)acrylate.

[0017] <4> The static charge image developer according to any one of <1> to <3>, wherein the resin layer contains a silicone resin.

[0018] <5> The static charge image developer according to any one of <1> to <4>, wherein the release agent contains paraffin wax.

[0019] <6> The static charge image developer according to any one of <1> to <5>, wherein, based on the content of the resin-coated carrier, the content of the nonionic surfactant is 0.5 ppm or more and 10 ppm or less by mass.

[0020] <7> A processing cartridge detachably mounted in an image forming apparatus, the processing cartridge including a developing member that stores the static charge image developer according to any one of <1> to <6> and develops a static charge image formed on the surface of an image holding member into a toner image.

[0021] <8> An image forming apparatus, comprising: an image holding member; a charging member that charges the surface of the image holding member; a static charge image forming member that forms a static charge image on the charged surface of the image holding member; a developing member that stores the static charge image developer according to any one of <1> to <6> and develops the static charge image formed on the surface of the image holding member into a toner image; a transfer member that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and a fixing member that fixes the toner image transferred to the surface of the recording medium.

[0022] <9>An image forming method includes: a charging step of charging the surface of an image holding member; an electrostatic charge image forming step of forming an electrostatic charge image on the charged surface of the image holding member; a developing step of developing the electrostatic charge image formed on the surface of the image holding member into a toner image using the electrostatic charge image developer according to any one of <1> to <6>; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0023] Effects of the Invention

[0024] The invention according to <1>, <2>, or <3> provides the following electrostatic charge image developer: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier exceeds 4 g / cm 3 The invention according to <4> provides the following electrostatic charge image developer: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the resin layer of the resin-coated carrier does not contain a silicone resin but contains a cyclohexyl methacrylate resin.

[0025] The invention according to <5> provides the following electrostatic charge image developer: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the toner particles do not contain paraffin but contain polyethylene wax as a release agent.

[0026] The invention according to <6> provides the following electrostatic charge image developer: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the content of the nonionic surfactant is less than 0.5 ppm or more than 10 ppm with respect to the mass of the resin-coated carrier.

[0027] The invention according to <7> provides the following processing cartridge: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm

[0028] The invention according to <8> provides the following image forming apparatus: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm 3 The invention according to <9> provides the following image forming method: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm

[0029] The invention according to <9> provides the following image forming method: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm 3 The invention according to <9> provides the following image forming method: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm

[0030] The invention according to <9> provides the following image forming method: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm 3 The invention according to <9> provides the following image forming method: suppressing the density difference occurring between images with different image formation speeds as compared with the case where the true specific gravity of the resin-coated carrier contained in the electrostatic charge image developer exceeds 4 g / cm Brief Description of the Drawings

[0031] Figure 1 is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment.

[0032] Figure 2 is a schematic configuration diagram showing an example of the processing cartridge detachably mounted in the image forming apparatus according to the present embodiment.

[0033] [Description of Reference Numerals]

[0034] 1Y, 1M, 1C, 1K: Photoconductor (an example of an image holding member)

[0035] 2Y, 2M, 2C, 2K: Charging roller (an example of a charging member)

[0036] 3: Exposure device (an example of an electrostatic latent image forming member)

[0037] 3Y, 3M, 3C, 3K: Laser beam

[0038] 4Y, 4M, 4C, 4K: Developing device (an example of a developing member)

[0039] 5Y, 5M, 5C, 5K: Primary transfer roller (an example of a primary transfer member)

[0040] 6Y, 6M, 6C, 6K: Photoconductor cleaning device (an example of a cleaning member)

[0041] 8Y, 8M, 8C, 8K: Toner cartridge

[0042] 10Y, 10M, 10C, 10K: Image forming unit

[0043] 20: Intermediate transfer belt (an example of an intermediate transfer member)

[0044] 22: Driving roller

[0045] 24: Supporting roller

[0046] 26: Secondary transfer roller (an example of a secondary transfer member)

[0047] 28: Fixing device (an example of a fixing member)

[0048] 30: Intermediate transfer member cleaning device

[0049] P: Recording paper (an example of a recording medium)

[0050] 107: Photoconductor (an example of an image holding member)

[0051] 108: Charging roller (an example of a charging member)

[0052] 109: Exposure device (an example of an electrostatic charge image forming member)

[0053] 111: Developing device (an example of a developing member)

[0054] 112: Transfer device (an example of a transfer member)

[0055] 113: Photoconductor cleaning device (an example of a cleaning member)

[0056] 115: Fixing device (an example of a fixing member)

[0057] 116: Mounting rail

[0058] 117: Frame

[0059] 118: Opening for exposure

[0060] 200: Processing cartridge

[0061] 300: Recording paper (an example of a recording medium) Detailed implementation manners

[0062] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples illustrate the embodiments and do not limit the scope of the embodiments.

[0063] In the present disclosure, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0064] In the numerical ranges described step by step in the present disclosure, the upper limit value or the lower limit value described in one numerical range may also be replaced with the upper limit value or the lower limit value of another numerically described range. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may also be replaced with the value shown in the examples.

[0065] In the present disclosure, the term "step" includes not only independent steps, but also, even in cases where it cannot be clearly distinguished from other steps, as long as the desired purpose of the step is achieved, it is also included in this term.

[0066] When the embodiments are described with reference to the drawings in the present disclosure, the configuration of the embodiments is not limited to the configuration shown in the drawings. In addition, the sizes of the components in each figure are conceptual sizes, and the relative relationship of the sizes between the components is not limited thereto.

[0067] In the present disclosure, various substances corresponding to each component may also be included. When the amount of each component in the composition is mentioned in the present disclosure, when there are various substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the various substances present in the composition.

[0068] In the present disclosure, various particles corresponding to each component may also be included. When there are various particles corresponding to each component in the composition, unless otherwise specified, the particle size of each component means the value of the mixture of the various particles present in the composition.

[0069] In the present disclosure, the expression “(meth)acrylic acid” means that it may be either “acrylic acid” or “methacrylic acid”.

[0070] In the present disclosure, “toner for electrostatic charge image development” is also abbreviated as “toner”, and “electrostatic charge image developer” is also abbreviated as “developer”.

[0071] <Electrostatic Charge Image Developer>

[0072] The developer of the present embodiment includes a toner and a resin-coated carrier. The toner includes toner particles, and the toner particles contain a binder resin, a release agent, and a nonionic surfactant. The resin-coated carrier has magnetic particles and a resin layer covering the magnetic particles, and the true specific gravity is 3 g / cm 3 or more and 4 g / cm 3 or less. The toner may also include an external additive externally added to the toner particles.

[0073] Compared with a developer having a true specific gravity of more than 4 g / cm 3 for the developer of the present embodiment, the density difference occurring between images with different image formation speeds is suppressed. As its mechanism, the following is speculated.

[0074] When forming an image on a recording medium, for the purpose of sufficiently transferring heat to the toner on the recording medium, sometimes the thicker the recording medium or the lower the thermal conductivity of the recording medium, the longer the time for the fixing member to contact the recording medium. Therefore, the thicker the recording medium or the lower the thermal conductivity of the recording medium, the slower the image formation speed. It is speculated that: if the image formation speed becomes slower, then correspondingly the rotation speed of the developing device also becomes slower, and as a result, due to the difference in the rotation speed of the developing device, the density of the developer on the sleeve of the developing device changes, and the state of the magnetic brush changes. As a result, it is speculated that a density difference will occur between images with different image formation speeds.

[0075] The inventors of the present invention conducted research and found that by using toner particles containing a nonionic surfactant and a true specific gravity of 3 g / cm 3 or more and 4 g / cm 3The following combination of resin-coated carriers can suppress the concentration difference. Since the affinity of the nonionic surfactant for the release agent is higher than that of the binder resin, it is speculated that the nonionic surfactant exists at the interface between the binder resin and the release agent in a manner that surrounds the release agent. Further, it is speculated that when pressure is applied to the toner particles due to agitation in the developing device, the release agent vibrates within the toner particles, and upon receiving this vibration, the nonionic surfactant moves to the surface of the toner particles and adheres to the surface of the resin-coated carrier. It is presumed that if an appropriate amount of nonionic surfactant is present on the surface of the resin-coated carrier, the state of the magnetic brush is likely to be stabilized, and even if the rotation speed of the developing device changes, the state of the magnetic brush is not likely to change. It is speculated that if the true specific gravity of the resin-coated carrier is 3 g / cm 3 or more and 4 g / cm 3 or less, then due to the agitation in the developing device, the pressure applied to the toner particles is appropriate, and the amount of nonionic surfactant that moves to the surface of the toner particles and adheres to the surface of the resin-coated carrier is appropriate, making it easy to stabilize the state of the magnetic brush. As a result, it is speculated that even if the image formation speed is different, a concentration difference is not likely to occur between images.

[0076] In the developer of the present embodiment, the true specific gravity of the resin-coated carrier is 3 g / cm 3 or more and 4 g / cm 3 or less. It is speculated that if the true specific gravity of the resin-coated carrier exceeds 4 g / cm 3 , then due to the agitation in the developing device, the pressure applied to the toner particles is strong, and the amount of nonionic surfactant that moves to the surface of the toner particles and adheres to the surface of the resin-coated carrier is excessive, making it difficult to stabilize the state of the magnetic brush.

[0077] On the other hand, in order to exhibit appropriate electrical properties as a carrier of the developer, the resin-coated carrier contains a magnetic material, so generally the true specific gravity is 3 g / cm 3 or more. Additionally, from the perspective of applying an appropriate pressure to the toner particles through agitation in the developing device, the specific gravity of the resin-coated carrier is 3 g / cm 3 or more.

[0078] From the above perspective, the true specific gravity of the resin-coated carrier is 3 g / cm 3 or more and 4 g / cm 3 or less, preferably 3.1 g / cm 3 or more and 3.9 g / cm 3 or less, and more preferably 3.2 g / cm 3 or more and 3.8 g / cm 3 or less.

[0079] The true specific gravity of the resin-coated carrier is measured by the pycnometer method specified in Japanese Industrial Standards (JIS) K0061:2001, "Methods for Measuring the Density and Specific Gravity of Chemical Products".

[0080] The true specific gravity of the resin-coated carrier can be controlled, for example, by making the magnetic particles contain resin and at the same time increasing or decreasing the amount of the contained resin; increasing or decreasing the coating rate of the resin layer, etc.

[0081] The developer of the present embodiment is prepared by mixing toner and a resin-coated carrier in an appropriate ratio. The mixing ratio (mass ratio) of toner to resin-coated carrier is preferably toner:resin-coated carrier = 1:100 to 30:100, more preferably 3:100 to 20:100.

[0082] Hereinafter, the details of the developer of the present embodiment will be described.

[0083] [Toner particles]

[0084] The toner particles contain at least a binder resin, a release agent, and a nonionic surfactant. The toner particles may also contain other resins, colorants, and other additives.

[0085] -Nonionic surfactant-

[0086] In the present embodiment, examples of the nonionic surfactant contained in the toner particles include: ether types such as polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene polyoxypropylene glycol; ester types formed by ester-bonding polyhydric alcohols such as glycerin, sorbitol, and sucrose with fatty acids; ether-ester types formed by adding ethylene oxide to esters containing polyhydric alcohols and fatty acids such as glycerin, sorbitol, and sucrose; fatty acid alkanol amido types, etc. Among them, polyoxyethylene alkyl ether is preferred, and polyoxyethylene lauryl ether is more preferred.

[0087] In the developer of the present embodiment, based on the mass of the resin-coated carrier in the developer, the amount of the nonionic surfactant in the developer is preferably 0.5 ppm or more and 10 ppm or less, more preferably 1 ppm or more and 5 ppm or less, and still more preferably 2.5 ppm or more and 3.5 ppm or less. By making the content of the nonionic surfactant within the above range, the density difference occurring between images with different image formation speeds can be more effectively suppressed.

[0088] In the developer of the present embodiment, the toner particles contain polyoxyethylene lauryl ether as a nonionic surfactant. The amount of polyoxyethylene lauryl ether in the developer is preferably 0.5 ppm or more and 10 ppm or less, more preferably 1 ppm or more and 5 ppm or less, and still more preferably 2.5 ppm or more and 3.5 ppm or less, based on the mass of the resin-coated carrier in the developer.

[0089] The method for measuring the content of the nonionic surfactant is as follows.

[0090] Separate the toner from the carrier using a sieve with a mesh size of 16 μm, wash the toner with water, and quantify the nonionic surfactant by liquid chromatography. Then, calculate the content (ppm) of the nonionic surfactant relative to the content of the resin-coated carrier constituting the developer.

[0091] The toner particles can contain a nonionic surfactant by using a nonionic surfactant as a surfactant when manufacturing the toner particles by a wet method (such as a coagulation-aggregation method, a suspension polymerization method, a dissolution-suspension method, etc.) described later.

[0092] -Binder resin-

[0093] The toner particles in the present embodiment preferably contain at least an amorphous resin, and more preferably contain an amorphous resin and a crystalline resin as the binder resin.

[0094] In the present embodiment, the "crystallinity" of a resin means having a distinct endothermic peak in differential scanning calorimetry (DSC) rather than a step-like heat absorption change. Specifically, it means that the half-width of the endothermic peak measured at a heating rate of 10 °C / min is within 10 °C. On the other hand, the "amorphousness" of a resin means that the half-width of the endothermic peak exceeds 10 °C, shows a step-like heat absorption change, or no distinct endothermic peak is confirmed.

[0095] -Amorphous resin-

[0096] The amorphous resin is not particularly limited, and preferably at least one of an amorphous polyester resin and an amorphous modified polyester resin obtained by modifying the amorphous polyester resin with at least one of styrene and (meth)acrylate.

[0097] The amorphous modified polyester resin obtained by modifying an amorphous polyester resin with at least one of styrene and (meth)acrylate includes, for example: a resin having a main chain containing an amorphous polyester resin and a side chain containing a styrene acrylic resin; a resin having a main chain containing a styrene acrylic resin and a side chain containing an amorphous polyester resin; a resin having a main chain formed by chemically bonding an amorphous polyester resin and a styrene acrylic resin; a resin having a main chain formed by chemically bonding an amorphous polyester resin and a styrene acrylic resin, and at least one side chain selected from a side chain containing an amorphous polyester resin and a side chain containing a styrene acrylic resin, etc.

[0098] In the present disclosure, the amorphous modified polyester resin obtained by modifying an amorphous polyester resin with at least one of styrene and (meth)acrylate is also referred to as a "mixed amorphous resin". In addition, the polyester resin part of the mixed amorphous resin is called a "polyester segment", and the part of the mixed amorphous resin containing at least one of styrene and (meth)acrylate polymerized is called a "styrene acrylic segment". In the mixed amorphous resin, the polyester segment and the styrene acrylic segment are chemically bonded.

[0099] -Mixed amorphous resin-

[0100] The mixed amorphous resin contained in the toner particles in the present embodiment is not particularly limited as long as it is an amorphous resin having a polyester segment and a styrene acrylic segment in one molecule.

[0101] ·Polyester segment

[0102] The polyester segment of the mixed amorphous resin refers to the part where ester bonds (-COO-) are continuous.

[0103] As the polyester segment of the mixed amorphous resin in the present embodiment, for example, a polycondensate of a polyol and a polycarboxylic acid can be cited.

[0104] As the polyol, for example, aliphatic diols (such as ethylene glycol, 1,2 - propanediol, 1,3 - propanediol, 1,2 - butanediol, 1,3 - butanediol, 1,4 - butanediol, 2,3 - butanediol, neopentyl glycol, 1,4 - butenediol, 1,5 - pentanediol, 1,6 - hexanediol, 1,8 - octanediol, 1,9 - nonanediol, 1,10 - decanediol, 1,12 - dodecanediol, etc.), alicyclic diols (such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (such as bisphenol A, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, etc.) can be cited.

[0105] As the polyol, a polyol having a valency of three or more that can be used together with a diol to obtain a crosslinked structure or a branched structure may also be used. Examples of the polyol having a valency of three or more include glycerol, trimethylolpropane, pentaerythritol, sorbitol, and the like.

[0106] The polyol may be used alone or in combination of two or more.

[0107] As the polyol, an aromatic diol is preferred, and at least one selected from the group consisting of an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A is more preferred, and a propylene oxide adduct of bisphenol A is further preferred. Here, the average number of moles of addition of the ethylene oxide adduct of bisphenol A or the propylene oxide adduct of bisphenol A is preferably 1 or more and 16 or less, more preferably 1.2 or more and 12 or less, further preferably 1.5 or more and 8 or less, and still further preferably 2 or more and 4 or less.

[0108] The total amount of the ethylene oxide adduct of bisphenol A and the propylene oxide adduct of bisphenol A in the total amount of the alcohol components constituting the polyester segment of the mixed amorphous resin is preferably 10 mol% or more and 90 mol% or less, more preferably 20 mol% or more and 80 mol% or less, and further preferably 30 mol% or more and 70 mol% or less.

[0109] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, pentenedioic acid, succinic acid, alkenyl succinic acids (e.g., dodecenyl succinic acid, octenyl succinic acid, etc.), adipic acid, sebacic acid, 1,12-dodecanedioic acid, azelaic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms) alkyl esters thereof.

[0110] The polycarboxylic acid may also be used together with a dicarboxylic acid to obtain a carboxylic acid having a valency of three or more that has a crosslinked structure or a branched structure. Examples of the carboxylic acid having a valency of three or more include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms) alkyl esters thereof, and the like.

[0111] The polycarboxylic acid may be used alone or in combination of two or more.

[0112] It is preferred that the carboxylic acid component of the polyester segment contains at least one non-aromatic dicarboxylic acid having a carbon-carbon unsaturated bond. The dicarboxylic acid becomes a part of the polyester segment by polycondensation with a polyol, and styrene-based or (meth)acrylate-based monomers are addition-polymerized with the carbon-carbon unsaturated bond derived from the dicarboxylic acid, whereby the styrene-acrylic segment is chemically bonded to the polyester segment.

[0113] Examples of the non-aromatic dicarboxylic acid having a carbon-carbon unsaturated bond include fumaric acid, maleic acid, 1,2,3,6-tetrahydrophthalic acid, alkenyl succinic acid (e.g., dodecenyl succinic acid, octenyl succinic acid, etc.), and anhydrides thereof. Among these, from the viewpoint of reactivity, fumaric acid is preferred.

[0114] · Styrene acrylic segment

[0115] Examples of the styrene acrylic segment of the mixed amorphous resin in the present embodiment include segments obtained by addition polymerization of addition polymerizable monomers. Examples of the addition polymerizable monomers constituting the styrene acrylic segment include styrenes, (meth)acrylates, and monomers having an ethylenically unsaturated double bond, which are generally used in the synthesis of styrene acrylic resins.

[0116] Examples of the styrenes constituting the styrene acrylic segment include substituted or unsubstituted styrene. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group or a salt thereof, etc. Specific examples of the styrenes include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid or a salt thereof, etc. Among these, styrene is preferred.

[0117] Examples of the (meth)acrylates constituting the styrene acrylic segment include (meth)acrylic acid alkyl esters (e.g., the alkyl group has 1 to 24 carbon atoms), (meth)acrylic acid benzyl ester, (meth)acrylic acid dimethylaminoethyl ester, etc. Among these, (meth)acrylic acid alkyl esters having an alkyl group with 1 to 18 carbon atoms are preferred, (meth)acrylic acid alkyl esters having an alkyl group with 1 to 12 carbon atoms are more preferred, and (meth)acrylic acid alkyl esters having an alkyl group with 1 to 8 carbon atoms are further preferred. Specific examples of the (meth)acrylic acid alkyl esters include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid (iso)propyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid pentyl ester, (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid decyl ester, (meth)acrylic acid dodecyl ester, (meth)acrylic acid palm ester, (meth)acrylic acid stearyl ester, (meth)acrylic acid docosyl ester, etc.

[0118] Preferably, at least one non-aromatic monocarboxylic acid having a carbon-carbon unsaturated bond is included in the monomers constituting the styrene-acrylic segment. The monocarboxylic acid becomes a part of the styrene-acrylic segment through addition polymerization, and the alcohol component of the polyester segment undergoes polycondensation with the carboxyl group derived from the monocarboxylic acid, whereby the styrene-acrylic segment and the polyester segment are compounded. As the non-aromatic monocarboxylic acid having a carbon-carbon unsaturated bond, one or more selected from acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred.

[0119] As other monomers constituting the styrene-acrylic segment, the following can be cited: olefins such as ethylene, propylene, and butadiene; vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as N-vinylpyrrolidone, etc.

[0120] The total amount of styrenes in the total amount of monomers constituting the styrene-acrylic segment of the mixed amorphous resin is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less.

[0121] (Meth)acrylates preferably account for 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less in the total amount of monomers constituting the styrene-acrylic segment of the mixed amorphous resin.

[0122] The total amount of styrenes and (meth)acrylates in the total amount of monomers constituting the styrene-acrylic segment of the mixed amorphous resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and further preferably 100%.

[0123] The total amount of the polyester segment and the styrene-acrylic segment in the entire mixed amorphous resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and further preferably 100%.

[0124] In the mixed amorphous resin, the proportion of the styrene-acrylic segment in the total amount of the polyester segment and the styrene-acrylic segment is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and still more preferably 10% by mass or more and 30% by mass or less.

[0125] The weight average molecular weight (Mw) of the mixed amorphous resin is preferably 5,000 or more and 500,000 or less, more preferably 10,000 or more and 100,000 or less, and still more preferably 15,000 or more and 50,000 or less.

[0126] The weight average molecular weight and number average molecular weight of the resin in the present disclosure are measured by gel permeation chromatography (GPC). The molecular weight measurement using GPC is carried out using a GPC: HLC-8120GPC manufactured by Tosoh as the measurement device and a column: TSKgel SuperHM-M (15 cm) manufactured by Tosoh in a THF solvent. The weight average molecular weight and number average molecular weight are calculated based on the measurement results and using a molecular weight calibration curve made from a monodisperse polystyrene standard sample.

[0127] The glass transition temperature (Tg) of the mixed amorphous resin is preferably 25°C or more and 80°C or less, more preferably 30°C or more and 70°C or less, and still more preferably 40°C or more and 60°C or less.

[0128] The glass transition temperature of the resin in the present disclosure is determined from the DSC curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined according to the "extrapolated glass transition initiation temperature" described in the method for determining the glass transition temperature in Japanese Industrial Standards (JIS) K7121:1987 "Plastics - Method for Determining Transition Temperatures".

[0129] The acid value of the mixed amorphous resin is preferably 5 mgKOH / g or more and 40 mgKOH / g or less, more preferably 10 mgKOH / g or more and 35 mgKOH / g or less, and still more preferably 15 mgKOH / g or more and 30 mgKOH / g or less.

[0130] The mixed amorphous resin is preferably manufactured by any one of the following methods (i) to (iii).

[0131] (i) After producing a polyester segment by polycondensation of a polyol and a polycarboxylic acid, addition polymerization of the monomers constituting the styrene acrylic segment is carried out.

[0132] (ii) After producing a styrene acrylic segment by addition polymerization of addition polymerizable monomers, polycondensation of a polyol and a polycarboxylic acid is carried out.

[0133] (iii) Polycondensation of a polyol and a polycarboxylic acid and addition polymerization of addition polymerizable monomers are carried out simultaneously.

[0134] -Amorphous polyester resin-

[0135] As the amorphous polyester resin, for example, polycondensates of polycarboxylic acids and polyols can be cited. As the amorphous polyester resin, both commercially available products and synthetic resins can be used.

[0136] As the polycarboxylic acid, for example, the following can be cited: aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, pentenedioic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof. Among these, as the polycarboxylic acid, aromatic dicarboxylic acids are preferably used, for example.

[0137] Trivalent or higher-valent carboxylic acids that can form a crosslinked structure or a branched structure by being used together with the dicarboxylic acid can also be used as the polycarboxylic acid. As the trivalent or higher-valent carboxylic acid, for example, the following can be cited: trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof, etc.

[0138] The polycarboxylic acid can be used alone or in combination of two or more.

[0139] As the polyol, for example, the following can be cited: aliphatic diols (such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, etc.), alicyclic diols (such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (such as ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyol, aromatic diols and alicyclic diols are preferably used, for example, and aromatic diols are more preferably used.

[0140] Trivalent or higher-valent polyols that can form a crosslinked structure or a branched structure by being used together with the diol can also be used as the polyol. As the trivalent or higher-valent polyol, for example, the following can be cited: glycerol, trimethylolpropane, pentaerythritol.

[0141] The polyol can be used alone or in combination of two or more.

[0142] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower.

[0143] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5000 or more and 1000000 or less, more preferably 7000 or more and 500000 or less. The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2000 or more and 100000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less.

[0144] The amorphous polyester resin can be obtained by a known production method. Specifically, for example, it can be obtained by the following method: setting the polymerization temperature to 180°C or more and 230°C or less, reducing the pressure in the reaction system as needed, and reacting while removing the water or alcohol generated during condensation.

[0145] When the raw material monomers are insoluble or incompatible at the reaction temperature, a high-boiling solvent can also be added as a dissolution aid to dissolve them. In such a case, the dissolution aid is distilled off while carrying out the polycondensation reaction. When there are monomers with poor compatibility in the copolymerization reaction, the monomers with poor compatibility can be pre-condensed with the acid or alcohol to be polycondensed with the monomers and then polycondensed with the main component.

[0146] In the present embodiment, the total proportion of the amorphous polyester resin and the mixed amorphous resin in the total amount of the amorphous resin contained as a binder resin in the toner particles is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, still more preferably 95% by mass or more and 100% by mass or less, and further preferably 100%.

[0147] - Crystalline resin -

[0148] In the present embodiment, the toner particles preferably contain a crystalline resin. There is no particular limitation on the crystalline resin, and at least one of a crystalline polyester resin and a crystalline modified polyester resin obtained by modifying the crystalline polyester resin with at least one of styrene and (meth)acrylate is preferred.

[0149] Examples of the crystalline modified polyester resin obtained by modifying the crystalline polyester resin with at least one of styrene and (meth)acrylate include: a resin having a main chain containing a crystalline polyester resin and a side chain containing a styrene acrylic resin; a resin having a main chain containing a styrene acrylic resin and a side chain containing a crystalline polyester resin; a resin having a main chain formed by chemical bonding of a crystalline polyester resin and a styrene acrylic resin; a resin having a main chain formed by chemical bonding of a crystalline polyester resin and a styrene acrylic resin, and at least one side chain selected from a side chain containing a crystalline polyester resin and a side chain containing a styrene acrylic resin, etc.

[0150] In the present disclosure, a crystalline modified polyester resin obtained by modifying a crystalline polyester resin with at least one of styrene and (meth)acrylate is also referred to as a "mixed crystalline resin". Further, the polyester resin portion of the mixed crystalline resin is referred to as a "polyester segment", and the portion of the mixed crystalline resin containing at least one of styrene and (meth)acrylate polymerized therein is referred to as a "styrene acrylate segment". In the mixed crystalline resin, the polyester segment and the styrene acrylate segment are chemically bonded to each other.

[0151] -Mixed crystalline resin-

[0152] In the present embodiment, the mixed crystalline resin contained in the toner particles is not particularly limited as long as it is a crystalline resin having a polyester segment and a styrene acrylate segment in one molecule.

[0153] ·Polyester segment

[0154] The polyester segment of the mixed crystalline resin refers to the portion where ester bonds (-COO-) are continuous.

[0155] As the polyester segment of the mixed crystalline resin in the present embodiment, for example, a polycondensate of a polyol and a polycarboxylic acid can be cited. In order to easily form a crystalline structure, the polyester segment is preferably a polycondensate of a linear aliphatic polymerizable monomer rather than a polymerizable monomer having an aromatic ring.

[0156] As the polyol, for example, aliphatic diols (e.g., linear aliphatic diols having 7 or more and 20 or less carbon atoms in the main chain portion) can be cited. As the aliphatic diol, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosane decanediol, etc. Among these, as the aliphatic diol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred.

[0157] Trivalent or higher alcohols that can form a crosslinked structure or a branched structure by being used together with the diol can also be used as the polyol. As the trivalent or higher alcohol, for example, glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. can be cited.

[0158] The polyol can be used alone or in combination of two or more.

[0159] As polycarboxylic acids, for example, the following can be mentioned: aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, etc., dibasic acids, etc.), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof.

[0160] Polycarboxylic acids can also be used in combination with dicarboxylic acids to obtain a crosslinked structure or a trivalent or higher carboxylic acid having a branched structure. As the trivalent carboxylic acid, for example, the following can be mentioned: aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, or lower (e.g., having 1 to 5 carbon atoms) alkyl esters thereof.

[0161] As polycarboxylic acids, dicarboxylic acids having a sulfonic acid group and dicarboxylic acids having an ethylenic double bond can also be used in combination with these dicarboxylic acids.

[0162] Polycarboxylic acids can be used alone or in combination of two or more.

[0163] Preferably, the carboxylic acid component of the polyester segment contains at least one non-aromatic dicarboxylic acid having a carbon-carbon unsaturated bond. The dicarboxylic acid becomes a part of the polyester segment by polycondensation with a polyol, and styrene-based or (meth)acrylate-based monomers are addition-polymerized with the carbon-carbon unsaturated bond derived from the dicarboxylic acid, whereby the styrene-acrylic segment is chemically bonded to the polyester segment.

[0164] As non-aromatic dicarboxylic acids having a carbon-carbon unsaturated bond, the following can be mentioned: fumaric acid, maleic acid, 1,2,3,6-tetrahydrophthalic acid, alkenylsuccinic acids (e.g., dodecenylsuccinic acid, octenylsuccinic acid, etc.), and anhydrides thereof. Among these, from the viewpoint of reactivity, fumaric acid is preferred.

[0165] · Styrene-acrylic segment

[0166] As the styrene-acrylic segment of the mixed crystalline resin in the present embodiment, for example, a segment obtained by addition-polymerizing addition-polymerizable monomers can be mentioned. As the addition-polymerizable monomers constituting the styrene-acrylic segment, styrene-based monomers, (meth)acrylate-based monomers, and monomers having an ethylenic unsaturated double bond, which are generally used for the synthesis of styrene-acrylic resins, can be mentioned.

[0167] Examples of the styrenics that constitute the styrene-acrylic segment include substituted or unsubstituted styrene. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group or a salt thereof. Specific examples of the styrenics include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid or a salt thereof. Among them, styrene is preferred.

[0168] Examples of the (meth)acrylates that constitute the styrene-acrylic segment include (meth)acrylic acid alkyl esters (for example, the alkyl group has 1 to 24 carbon atoms), benzyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, etc. Among them, a (meth)acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group is preferred, a (meth)acrylic acid alkyl ester having 1 to 12 carbon atoms in the alkyl group is more preferred, and a (meth)acrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group is further preferred. Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, docosyl (meth)acrylate, etc.

[0169] It is preferred that at least one non-aromatic monocarboxylic acid having a carbon-carbon unsaturated bond is included in the monomers that constitute the styrene-acrylic segment. The monocarboxylic acid becomes a part of the styrene-acrylic segment by addition polymerization, and the alcohol component of the polyester segment undergoes polycondensation with the carboxyl group derived from the monocarboxylic acid, whereby the styrene-acrylic segment and the polyester segment are compounded. As the non-aromatic monocarboxylic acid having a carbon-carbon unsaturated bond, one or more selected from acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred.

[0170] Examples of the other monomers that constitute the styrene-acrylic segment include olefins such as ethylene, propylene, and butadiene; vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether; vinylidene dihalides such as vinylidene dichloride; N-vinyl compounds such as N-vinylpyrrolidone.

[0171] The total amount of the styrenics in the total amount of the monomers that constitute the styrene-acrylic segment of the mixed crystalline resin is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and further preferably 40% by mass or more and 60% by mass or less.

[0172] The total amount of (meth)acrylates in the total amount of monomers constituting the styrene-acrylic segment of the mixed crystalline resin is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less.

[0173] The total amount of styrenes and (meth)acrylates in the total amount of monomers constituting the styrene-acrylic segment of the mixed crystalline resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and further preferably 100% by mass.

[0174] The total amount of the polyester segment and the styrene-acrylic segment in the whole mixed crystalline resin is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and further preferably 100% by mass.

[0175] In the mixed crystalline resin, the proportion of the styrene-acrylic segment in the total amount of the polyester segment and the styrene-acrylic segment is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and still more preferably 10% by mass or more and 30% by mass or less.

[0176] The melting temperature of the mixed crystalline resin is preferably 50 °C or more and 100 °C or less, more preferably 55 °C or more and 90 °C or less, and still more preferably 60 °C or more and 85 °C or less.

[0177] In the present disclosure, the melting temperature of the resin is determined based on the DSC curve obtained by differential scanning calorimetry (DSC), and is determined according to the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121:1987 "Method for Measuring the Transition Temperature of Plastics".

[0178] The weight average molecular weight (Mw) of the mixed crystalline resin is preferably 6,000 or more and 35,000 or less.

[0179] The mixed crystalline resin is preferably produced by any one of the following methods (i) to (iii).

[0180] (i) After producing a polyester segment by polycondensation of a polyol and a polycarboxylic acid, the monomers constituting the styrene-acrylic segment are subjected to addition polymerization.

[0181] (ii) After producing a styrene-acrylic segment by addition polymerization of an addition polymerizable monomer, a polyol and a polycarboxylic acid are subjected to polycondensation.

[0182] (iii) Polycondensation of a polyol and a polycarboxylic acid and addition polymerization of an addition polymerizable monomer are carried out simultaneously.

[0183] - Crystalline polyester resin -

[0184] As the crystalline polyester resin, for example, a condensate of a polycarboxylic acid and a polyol can be cited. As the crystalline polyester resin, either a commercially available product or a synthetic resin can be used.

[0185] Here, in order to easily form a crystalline structure, the crystalline polyester resin is preferably a condensate of a linear aliphatic polymerizable monomer rather than an aromatic ring-containing polymerizable monomer.

[0186] As the polycarboxylic acid, for example, the following can be cited: aliphatic dicarboxylic acids (such as oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, etc. as dibasic acids), anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof.

[0187] A polycarboxylic acid can also be used in combination with a dicarboxylic acid to obtain a crosslinked structure or a trivalent or higher carboxylic acid having a branched structure. As the trivalent carboxylic acid, for example, the following can be cited: aromatic carboxylic acids (such as 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, or lower (for example, having 1 to 5 carbon atoms) alkyl esters thereof.

[0188] As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond can also be used in combination with these dicarboxylic acids.

[0189] The polycarboxylic acid can be used alone or in combination of two or more.

[0190] As the polyol, for example, aliphatic diols (such as linear aliphatic diols having 7 or more and 20 or less carbon atoms in the main chain part) can be cited. As the aliphatic diol, for example, the following can be cited: ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosane decanediol, etc. Among these, as the aliphatic diol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred.

[0191] Polyhydric alcohols can also be used in combination with diols to obtain a trivalent or higher alcohol having a crosslinked structure or a branched structure. Examples of the trivalent or higher alcohol include glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc.

[0192] The polyhydric alcohol can be used alone or in combination of two or more.

[0193] Here, the content of the aliphatic diol in the polyhydric alcohol can be set to 80 mol% or more, preferably 90 mol% or more.

[0194] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and still more preferably 60°C or higher and 85°C or lower.

[0195] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0196] When the toner particles in the present embodiment contain a crystalline resin, the content of the crystalline resin is preferably 5% by mass or more and 40% by mass or less, more preferably 8% by mass or more and 30% by mass or less, and still more preferably 10% by mass or more and 20% by mass or less, relative to the total binder resin.

[0197] In the present embodiment, the total proportion of the crystalline polyester resin and the mixed crystalline resin in the total amount of the crystalline resin contained as the binder resin in the toner particles is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, still more preferably 95% by mass or more and 100% by mass or less, and further preferably 100%.

[0198] Relative to the whole toner particles, the content of the binder resin is preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and still more preferably 60% by mass or more and 85% by mass or less.

[0199] -Release agent-

[0200] Examples of the release agent include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral and / or petroleum-based waxes such as montan wax; ester waxes such as fatty acid esters and montanic acid esters. The release agent is not limited thereto.

[0201] The melting temperature of the release agent is preferably 50° C. to 110° C., more preferably 60° C. to 100° C. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) according to the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121:1987 "Method for determining transition temperatures of plastics".

[0202] The content of the releasing agent is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the entire toner particles.

[0203] An example of the release agent is paraffin wax, and the paraffin wax preferably has a melting temperature of 60° C. to 120° C., and more preferably has a melting temperature of 85° C. to 105° C.

[0204] An example of the release agent is polyethylene wax, which preferably has a melting temperature of 60° C. to 120° C., and more preferably has a melting temperature of 85° C. to 105° C.

[0205] An example of the release agent is ester wax, which preferably has a melting temperature of 60° C. to 120° C., and more preferably has a melting temperature of 85° C. to 105° C.

[0206] -Colorants-

[0207] Examples of the colorant include carbon black, chrome yellow, Hansa yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watchung red, permanent red, brilliant carmine 3B, brilliant carmine 6B, Dupont Oil Red, pyrazolone red, lithotripter red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, calco oil blue, and calco blue. oilblue), methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate and other pigments; acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazole and other dyes.

[0208] The coloring agent may be used alone or in combination of two or more.

[0209] The colorant may be a surface-treated colorant as required, or may be used in combination with a dispersant. In addition, a plurality of colorants may be used in combination.

[0210] The content of the colorant is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 15% by mass or less, relative to the whole toner particles.

[0211] -Other additives-

[0212] Examples of other additives include known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0213] -Properties of toner particles, etc.-

[0214] The toner particles may be single-layer toner particles or so-called core-shell structured toner particles including a core part (core particles) and a coating layer (shell layer) covering the core part. The core-shell structured toner particles may include, for example, a core part composed of a binder resin and other additives such as a colorant and a release agent as needed, and a coating layer composed of a binder resin.

[0215] The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, more preferably 4 μm or more and 8 μm or less.

[0216] The various average particle diameters and various particle size distribution indexes of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) and using ISOTON-II (manufactured by Beckman Coulter, Inc.) as the electrolyte.

[0217] At the time of measurement, as a dispersant, 0.5 mg or more and 50 mg or less of the measurement sample is added to 2 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolyte.

[0218] The electrolyte in which the sample is suspended is subjected to a 1-minute dispersion treatment using an ultrasonic disperser, and the particle size distribution of particles having a particle diameter in the range of 2 μm or more and 60 μm or less is measured using a Coulter Multisizer II and a pore having a pore diameter of 100 μm. The number of sampled particles is 50,000.

[0219] For the particle size ranges (channels) obtained by dividing based on the measured particle size distribution, the cumulative distributions of volume and number are plotted starting from the smaller diameter side, and the particle diameter at which the cumulative reaches 16% is defined as the volume particle diameter D16v and the number particle diameter D16p, the particle diameter at which the cumulative reaches 50% is defined as the volume average particle diameter D50v and the cumulative number average particle diameter D50p, and the particle diameter at which the cumulative reaches 84% is defined as the volume particle diameter D84v and the number particle diameter D84p.

[0220] Using these, the volume particle size distribution index (GSDv) is calculated as (D84v / D16v) 1 / 2 , and the number particle size distribution index (GSDp) is calculated as (D84p / D16p) 1 / 2 .

[0221] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, more preferably 0.95 or more and 0.98 or less.

[0222] The average circularity of the toner particles is obtained by (equivalent circle circumference) / (circumference) [(circumference of a circle having the same projected area as the particle image) / (circumference of the particle projection image)]. Specifically, it is the value measured by the following method.

[0223] First, it is obtained using the following flow-type particle image analysis device (FPIA-3000 manufactured by Sysmex Corporation): The toner particles to be measured are aspirated and extracted to form a flat flow, and are made to emit stroboscopic light briefly, thereby importing the particle image in the form of a still image and performing image analysis on the particle image. Then, the number of samples when calculating the average circularity is set to 3500.

[0224] In the case where the toner has an external additive, after dispersing the toner (developer) to be measured in water containing a surfactant, ultrasonic treatment is performed to obtain toner particles from which the external additive has been removed.

[0225] [External additive]

[0226] Examples of the external additive include inorganic particles. Examples of the inorganic particles include: SiO 2 , TiO 2 , Al 2 O 3 , CuO, ZnO, SnO 2 , CeO 2 , Fe 2 O 3 , MgO, BaO, CaO, K 2 O, Na 2 O, ZrO 2, CaO·SiO 2 , K 2 O·(TiO 2 )n, Al 2 O 3 ·2SiO 2 , CaCO 3 , MgCO 3 , BaSO 4 , MgSO 4 and other inorganic particles.

[0227] The surface of the inorganic particles as external additives can be subjected to a hydrophobization treatment. The hydrophobization treatment is carried out, for example, by immersing the inorganic particles in a hydrophobization treatment agent. The hydrophobization treatment agent is not particularly limited, and examples thereof include: silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. These can be used alone or in combination of two or more. For example, relative to 100 parts by mass of the inorganic particles, the amount of the hydrophobization treatment agent is usually 1 part by mass or more and 10 parts by mass or less.

[0228] As external additives, resin particles (resin particles such as polystyrene, polymethyl methacrylate, melamine resin, etc.), cleaning activators (for example, metal salts of higher fatty acids represented by zinc stearate, particles of fluorine-based high molecular weight substances), etc. can also be cited.

[0229] Relative to the toner particles, the externally added amount of the external additive is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 2.0% by mass or less.

[0230] [Method for manufacturing toner]

[0231] The toner of this embodiment is obtained by externally adding an external additive to the toner particles after manufacturing the toner particles.

[0232] The toner particles can also be manufactured by any one of a dry method (for example, a kneading and pulverizing method, etc.) and a wet method (for example, a coagulation and coalescence method, a suspension polymerization method, a dissolution and suspension method, etc.). These manufacturing methods are not particularly limited, and known manufacturing methods can be adopted. Among these, the toner particles can be obtained by the coagulation and coalescence method.

[0233] Specifically, for example, in the case of manufacturing toner particles by the agglomeration and coalescence method, the toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion liquid in which resin particles that become a binder resin are dispersed (resin particle dispersion liquid preparation step); a step of causing the resin particles (and other particles as needed) to agglomerate in the resin particle dispersion liquid (or the dispersion liquid obtained by mixing other particle dispersion liquids as needed) to form agglomerated particles (agglomerated particle formation step); and a step of heating the agglomerated particle dispersion liquid in which the agglomerated particles are dispersed to cause the agglomerated particles to fuse and / or coalesce to form toner particles (fusion and / or coalescence step).

[0234] Hereinafter, the details of each step will be described. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed by the user. Of course, other additives other than the colorant and the release agent may also be used.

[0235] - Resin particle dispersion liquid preparation step -

[0236] Prepare a resin particle dispersion liquid in which resin particles that become a binder resin are dispersed, and for example, a colorant particle dispersion liquid in which colorant particles are dispersed, and a release agent particle dispersion liquid in which release agent particles are dispersed.

[0237] The resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0238] Examples of the dispersion medium used in the resin particle dispersion liquid include aqueous media. Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols. These can be used alone or in combination of two or more.

[0239] Examples of the surfactant include anionic surfactants such as sulfate ester salts, sulfonates, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycol series, alkylphenol ethylene oxide adduct series, and polyol series. Among these, anionic surfactants and cationic surfactants are particularly preferable. The nonionic surfactant can also be used in combination with an anionic surfactant or a cationic surfactant. The surfactant can be used alone or in combination of two or more.

[0240] In a resin particle dispersion, as a method for dispersing resin particles in a dispersion medium, for example, general dispersion methods such as a rotary shear type homogenizer, or a ball mill, sand mill, dyno mill, etc. having a medium can be cited. In addition, depending on the type of resin particles, the phase inversion emulsification method can also be used to disperse the resin particles in the dispersion medium. The so-called phase inversion emulsification method is as follows: the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, an alkali is added to the organic continuous phase (O phase) and neutralized, and then an aqueous medium (W phase) is added, whereby phase inversion from W / O to O / W is carried out, and the resin is dispersed in the aqueous medium in the form of particles.

[0241] The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and still more preferably 0.1 μm or more and 0.6 μm or less.

[0242] The volume average particle diameter of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction type particle size distribution measuring device (for example, LA-700 manufactured by Horiba, Ltd.). For the divided particle size ranges (channels), a cumulative distribution is plotted for the volume starting from the small particle size side, and the particle diameter at which the cumulative reaches 50% with respect to the total particles is measured as the volume average particle diameter D50v. Furthermore, the volume average particle diameter of the particles in other dispersions is measured in the same manner.

[0243] The content of the resin particles contained in the resin particle dispersion is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less.

[0244] Similarly to the resin particle dispersion, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared. That is, regarding the volume average particle diameter, dispersion medium, dispersion method, and content of the particles in the resin particle dispersion, the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion are the same.

[0245] - Agglomerate particle formation step -

[0246] Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed.

[0247] Then, in the mixed dispersion, the resin particles are heterocoagulated with the colorant particles and the release agent particles to form agglomerate particles having a diameter close to the diameter of the target toner particles and containing the resin particles, the colorant particles, and the release agent particles.

[0248] Specifically, for example, a flocculant is added to the mixed dispersion liquid, and the pH value of the mixed dispersion liquid is adjusted to be acidic (for example, the pH value is 2 or more and 5 or less). After adding a dispersion stabilizer as needed, it is heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles - 30°C or more and the glass transition temperature - 10°C or less), and the particles dispersed in the mixed dispersion liquid are flocculated to form flocculated particles.

[0249] In the step of forming flocculated particles, for example, for the mixed dispersion liquid, a flocculant may be added under stirring at room temperature (for example, 25°C) using a rotary shear type homogenizer, the pH value of the mixed dispersion liquid is adjusted to be acidic (for example, the pH value is 2 or more and 5 or less), and after adding a dispersion stabilizer as needed, heating is performed.

[0250] As the flocculant, for example, surfactants having a polarity opposite to that of the surfactant contained in the mixed dispersion liquid, inorganic metal salts, and metal complexes having a valence of 2 or more can be cited. When using a metal complex as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved.

[0251] As needed, a metal ion and a complex of the flocculant or an additive forming a similar bond may also be used together with the flocculant. As the additive, a chelating agent can be preferably used.

[0252] As the inorganic metal salts, for example, metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide can be cited.

[0253] As the chelating agent, a water-soluble chelating agent can also be used. As the chelating agent, for example, hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as imino diacetic acid (IDA), nitrilo triacetic acid (NTA), and ethylene diamine tetraacetic acid (EDTA) can be cited.

[0254] Relative to 100 parts by mass of the resin particles, the addition amount of the chelating agent is preferably 0.01 part by mass or more and 5.0 parts by mass or less, more preferably 0.1 part by mass or more and less than 3.0 parts by mass.

[0255] -Fusion and / or integration step-

[0256] Next, the dispersion liquid of agglomerated particles in which the agglomerated particles are dispersed is heated to, for example, a temperature above the glass transition temperature of the resin particles (for example, a temperature 10°C to 30°C higher than the glass transition temperature of the resin particles), so that the agglomerated particles are fused and / or united to form toner particles.

[0257] The toner particles are obtained through the above steps.

[0258] Furthermore, the toner particles can also be manufactured through the following steps: after obtaining the dispersion liquid of agglomerated particles in which the agglomerated particles are dispersed, the dispersion liquid of agglomerated particles is further mixed with the dispersion liquid of resin particles in which the resin particles are dispersed, and agglomeration is carried out in such a way that the resin particles adhere to the surface of the agglomerated particles to form the second agglomerated particles; and the dispersion liquid of the second agglomerated particles in which the second agglomerated particles are dispersed is heated to fuse and / or unite the second agglomerated particles to form toner particles with a core-shell structure.

[0259] After the fusion and / or unification step is completed, known cleaning steps, solid-liquid separation steps, and drying steps are performed on the toner particles formed in the solution to obtain the toner particles in a dry state. From the perspective of chargeability, the cleaning step can be fully carried out by replacement cleaning using ion-exchanged water. From the perspective of productivity, the solid-liquid separation step can be carried out by suction filtration, pressure filtration, etc. From the perspective of productivity, the drying step can be carried out by freeze drying, fluidized bed drying, flash drying, vibration-type fluidized bed drying, etc.

[0260] Moreover, the toner of the present embodiment can be manufactured, for example, by adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V-type blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, if necessary, a vibrating sieve, an air classifier, etc. can also be used to remove the coarse particles of the toner.

[0261] [Resin-coated carrier]

[0262] The resin-coated carrier has magnetic particles and a resin layer covering the magnetic particles.

[0263] -Magnetic particles-

[0264] The magnetic particles are not particularly limited, and known magnetic particles that can be used as the core material of the carrier can be applied. As the magnetic particles, specifically, particles of magnetic metals such as iron, nickel, and cobalt can be listed; particles of magnetic oxides such as ferrite and magnetite; resin-impregnated magnetic particles obtained by impregnating a resin into porous magnetic powder; magnetic powder-dispersed resin particles prepared by dispersing magnetic powder in a resin and formulating them, etc.

[0265] The true specific gravity of the magnetic particles is preferably 3 g / cm 3Above and 4 g / cm 3 Below, more preferably 3.1 g / cm 3 Above and 3.9 g / cm 3 Below, further preferably 3.2 g / cm 3 Above and 3.8 g / cm 3 Below. The true specific gravity of the magnetic particles is controlled, for example, by incorporating a resin into the magnetic particles and simultaneously increasing or decreasing the amount of the incorporated resin.

[0266] The true specific gravity of the magnetic particles is measured according to the pycnometer method specified in JIS K0061:2001 "Methods for Measuring the Density and Specific Gravity of Chemical Products".

[0267] The volume average particle diameter of the magnetic particles is, for example, 10 μm or more and 500 μm or less, preferably 20 μm or more and 180 μm or less, more preferably 25 μm or more and 60 μm or less.

[0268] Regarding the magnetic force of the magnetic particles, the saturation magnetization in a magnetic field of 3000 oersted is, for example, 50 emu / g or more, preferably 60 emu / g or more. The measurement of the saturation magnetization is carried out using a vibrating sample type magnetic measurement device VSMP10-15 (manufactured by Toei Industry Co., Ltd.). The measurement sample is placed in a cell with an inner diameter of 7 mm and a height of 5 mm and assembled to the device. During the measurement, a magnetic field is applied and scanned up to a maximum of 3000 oersted. Then, the applied magnetic field is reduced, and a hysteresis curve is produced on a recording paper. The saturation magnetization, residual magnetization, and coercive force are obtained from the data of the curve.

[0269] The volume resistivity (20 °C) of the magnetic particles is, for example, 1×10 5 Ω·cm or more and 1×10 9 Ω·cm or less, preferably 1×10 7 Ω·cm or more and 1×10 9 Ω·cm or less.

[0270] The volume resistivity (Ω·cm) of the magnetic particles is measured as follows. The sample is placed flat on a circular electrode plate with an area of 20 cm 2 to form a layer with a thickness of 1 mm or more and 3 mm or less. Another circular electrode plate with an area of 20 cm 2The layer is sandwiched by circular electrode plates. To eliminate the voids between the specimens, a load of 4 kg is applied to the circular electrode plates disposed on the layer, and then the thickness (cm) of the layer is measured. An electrometer and a high-voltage power supply generating device are connected to the circular electrode plates above and below the layer. A high voltage is applied to the two circular electrode plates such that the electric field becomes 103.8 V / cm, and the current value (A) flowing at this time is read. The measurement environment is set to a temperature of 20°C and a relative humidity of 50%. The calculation formula for the volume resistivity (Ω·cm) of the specimen is shown in the following formula.

[0271] R = E × 20 / (I - I 0 ) / L

[0272] In the above formula, R is the volume resistivity (Ω·cm) of the specimen, E is the applied voltage (V), I is the current value (A), I 0 is the current value (A) when the applied voltage is 0 V, and L is the thickness (cm) of the layer. The coefficient 20 is the area (cm 2 ) of the circular electrode plate.

[0273] - Resin layer coated with magnetic particles -

[0274] Examples of the resin constituting the resin layer include: styrene-acrylic copolymer; polyolefin resins such as polyethylene and polypropylene; polyvinyl-based or polyvinylidene-based resins such as polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; silicone resins such as pure silicone resins containing organosiloxane bonds or modified products thereof; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyester; polyurethane; polycarbonate; amino resins such as urea-formaldehyde resin; and epoxy resin.

[0275] From the viewpoint of suppressing the density difference that appears between images with different image formation speeds, the resin layer preferably contains a silicone resin. As the silicone resin, a pure silicone resin containing an organosiloxane bond is preferred.

[0276] The proportion of the silicone resin in all the resins contained in the resin layer is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably substantially all the resins are silicone resins.

[0277] For the purpose of controlling charging or resistance, the resin layer may also contain inorganic particles. Examples of the inorganic particles include: carbon black; metals such as gold, silver, and copper; metal compounds such as barium sulfate, aluminum borate, potassium titanate, titanium oxide, zinc oxide, tin oxide, antimony-doped tin oxide, indium-tin-doped oxide, and aluminum-doped zinc oxide; and resin particles coated with a metal.

[0278] As a method for forming a resin layer on the surface of magnetic particles, for example, a wet method and a dry method can be cited. The wet method is a method using a solvent in which the resin constituting the resin layer is dissolved or dispersed. On the other hand, the dry manufacturing method is a method that does not use the solvent.

[0279] As the wet method, for example, an impregnation method in which magnetic particles are impregnated and coated in a resin solution for forming a resin layer; a spraying method in which the resin solution for forming a resin layer is sprayed onto the surface of magnetic particles; a fluidized bed method in which the resin solution for forming a resin layer is sprayed in a state where magnetic particles are fluidized in a fluidized bed; a kneading coater method in which magnetic particles and the resin solution for forming a resin layer are mixed in a kneading coater and the solvent is removed, etc.

[0280] The resin solution for forming a resin layer used in the wet method is prepared by dissolving or dispersing a resin and other components in a solvent. As the solvent, as long as it is a solvent that dissolves or disperses the resin, there is no particular limitation, and for example, aromatic hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane are used.

[0281] As the dry method, for example, a method of heating a mixture of magnetic particles and a resin for forming a resin layer in a dry state to form a resin layer can be cited. Specifically, for example, magnetic particles and a resin for forming a resin layer are mixed in a gas phase and heated and melted to form a resin layer.

[0282] The thickness of the resin layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.3 μm or more and 5 μm or less.

[0283] The coating rate of the resin layer on the surface of the resin-coated carrier is, for example, 80% or more and 100% or less, and 90% or more and 100% or less.

[0284] The coating rate of the resin layer on the surface of the resin-coated carrier is determined by X-ray photoelectron spectroscopy (XPS) using the following method.

[0285] A resin-coated carrier to be used as an object and magnetic particles after removing the resin layer from the resin-coated carrier used as an object. As a method for removing the resin layer from the resin-coated carrier, for example, a method of dissolving the resin component with an organic solvent to remove the resin layer, a method of removing the resin layer by heating at around 800 °C to disappear the resin component, etc. can be cited. The resin-coated carrier and the magnetic particles after removing the resin layer are used as measurement samples respectively, and Fe (atomic %) is quantified by XPS, and (Fe of the resin-coated carrier) ÷ (Fe of the magnetic particles) × 100 is calculated to obtain the exposure ratio (%) of the magnetic particles, and (100 - exposure ratio of the magnetic particles) is taken as the coating rate (%) of the resin layer.

[0286] The coating rate of the resin layer on the surface of the resin-coated carrier can be controlled by the amount of the resin used in the formation of the resin layer. The more the amount of the resin relative to the amount of the magnetic particles, the greater the coating rate.

[0287] -Properties of the resin-coated carrier-

[0288] The volume average particle diameter of the resin-coated carrier is preferably 15 μm or more and 510 μm or less, more preferably 20 μm or more and 180 μm or less, and still more preferably 25 μm or more and 60 μm or less.

[0289] Regarding the magnetic force of the resin-coated carrier, the saturation magnetization in a magnetic field of 1000 Oe is, for example, 40 emu / g or more, preferably 50 emu / g or more. The measurement of the saturation magnetization is carried out in the same manner as the measurement of the saturation magnetization of the magnetic particles, with a maximum scan up to 1000 Oe.

[0290] The volume resistivity (20 °C) of the resin-coated carrier is, for example, 1×10 7 Ω·cm or more and 1×10 15 Ω·cm or less, preferably 1×10 8 Ω·cm or more and 1×10 14 Ω·cm or less, more preferably 1×10 8 Ω·cm or more and 1×10 13 Ω·cm or less. The measurement of the volume resistivity of the resin-coated carrier is carried out in the same manner as the measurement of the volume resistivity of the magnetic particles.

[0291] <Image forming apparatus, image forming method>

[0292] The image forming apparatus and image forming method of the present embodiment will be described.

[0293] The image forming apparatus according to the present embodiment includes: an image holding member; a charging member that charges the surface of the image holding member; an electrostatic latent image forming member that forms an electrostatic latent image on the charged surface of the image holding member; a developing member that stores an electrostatic latent image developer and develops the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer; a transfer member that transfers the toner image formed on the surface of the image holding member to the surface of a recording medium; and a fixing member that fixes the toner image transferred to the surface of the recording medium. Further, as the electrostatic latent image developer, the electrostatic latent image developer according to the present embodiment can be applied.

[0294] In the image forming apparatus according to the present embodiment, an image forming method (the image forming method according to the present embodiment) is implemented. The image forming method includes: a charging step of charging the surface of the image holding member; an electrostatic latent image forming step of forming an electrostatic latent image on the charged surface of the image holding member; a developing step of developing the electrostatic latent image formed on the surface of the image holding member into a toner image using the electrostatic latent image developer according to the present embodiment; a transfer step of transferring the toner image formed on the surface of the image holding member to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0295] The image forming apparatus according to the present embodiment can be applied to the following well-known image forming apparatuses: a direct transfer type apparatus that directly transfers the toner image formed on the surface of the image holding member to a recording medium; an intermediate transfer type apparatus that transfers the toner image formed on the surface of the image holding member to the surface of an intermediate transfer member once and then transfers the toner image transferred to the surface of the intermediate transfer member to the surface of a recording medium twice; an apparatus including a cleaning member that cleans the surface of the image holding member before charging after the transfer of the toner image; an apparatus including a discharging member that discharges the surface of the image holding member before charging by irradiating an erasing light after the transfer of the toner image, and the like.

[0296] When the image forming apparatus according to the present embodiment is an intermediate transfer type apparatus, for example, the transfer member can be configured as follows. The configuration has an intermediate transfer member whose surface the toner image is transferred to, a primary transfer member that transfers the toner image formed on the surface of the image holding member to the surface of the intermediate transfer member once, and a secondary transfer member that transfers the toner image transferred to the surface of the intermediate transfer member to the surface of a recording medium twice.

[0297] In the image forming apparatus according to the present embodiment, for example, the portion including the developing member may also be a cartridge structure (processing cartridge) that is detachably mounted on the image forming apparatus. As the processing cartridge, for example, a processing cartridge that stores the electrostatic latent image developer according to the present embodiment and includes a developing member can be preferably used.

[0298] Hereinafter, an example of the image forming apparatus according to the present embodiment will be shown, but it is not limited thereto. In the following description, the main parts shown in Figure 1 will be described, and the description of the other parts will be omitted.

[0299] Figure 1 is a schematic configuration diagram showing the image forming apparatus according to the present embodiment.

[0300] Figure 1 The image forming apparatus shown includes electrophotographic first to fourth image forming units 10Y, 10M, 10C, and 10K (image forming members) that output images of various colors of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter, sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may also be processing cartridges detachably mounted on the image forming apparatus.

[0301] Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 is extended through each unit. The intermediate transfer belt 20 is wound around a driving roller 22 and a supporting roller 24 and travels in the direction from the first unit 10Y toward the fourth unit 10K ( Figure 1 rotates clockwise in ). A force is applied to the supporting roller 24 in a direction away from the driving roller 22 by a spring or the like (not shown), thereby applying tension to the intermediate transfer belt 20 wound around both of them. An intermediate transfer body cleaning device 30 is included on the image holding body side of the intermediate transfer belt 20 facing the driving roller 22.

[0302] Developing devices (an example of developing members) 4Y, 4M, 4C, and 4K of each of the units 10Y, 10M, 10C, and 10K are respectively supplied with yellow, magenta, cyan, and black toner accommodated in toner cartridges 8Y, 8M, 8C, and 8K.

[0303] The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore, the first unit 10Y that forms a yellow image disposed on the upstream side in the traveling direction of the intermediate transfer belt will be representatively described here.

[0304] Unit 1 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, there are sequentially arranged: a charging roller (an example of a charging member) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic latent image forming member) 3 that exposes the charged surface with a laser beam 3Y based on an image signal that has been color-separated to form an electrostatic latent image; a developing device (an example of a developing member) 4Y that supplies charged toner to the electrostatic latent image and develops the electrostatic latent image; a primary transfer roller (an example of a primary transfer member) 5Y that transfers the developed toner image onto an intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning member) 6Y that removes the toner remaining on the surface of the photoreceptor 1Y after primary transfer.

[0305] The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is located at a position facing the photoreceptor 1Y. A bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, 5K of each unit. Each bias power source changes the value of the transfer bias applied to each primary transfer roller by control using a control unit (not shown).

[0306] Hereinafter, the operation of forming a yellow image in Unit 1 10Y will be described.

[0307] First, before the operation, the surface of the photoreceptor 1Y is charged to a potential of -600 V to -800 V by the charging roller 2Y.

[0308] The photoreceptor 1Y is formed by laminating a photosensitive layer on a substrate having conductivity (for example, a volume resistivity of 1 × 10 -6 Ω·cm or less at 20°C). The photosensitive layer is generally a high resistance (the resistance of a general resin) and has the property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam. Therefore, based on the image data for yellow from a control unit (not shown), the charged surface of the photoreceptor 1Y is irradiated with the laser beam 3Y from the exposure device 3. Thereby, an electrostatic latent image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

[0309] The so-called electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and is a so-called negative latent image formed by the specific resistance of the irradiated portion of the photosensitive layer decreasing due to the laser beam 3Y, the charged charges on the surface of the photoreceptor 1Y flowing, while the charges in the portion not irradiated with the laser beam 3Y remaining.

[0310] The electrostatic latent image formed on the photoreceptor 1Y rotates to a predetermined developing position as the photoreceptor 1Y moves. Then, at the developing position, the electrostatic latent image on the photoreceptor 1Y is developed into a toner image and visualized by the developing device 4Y.

[0311] In the developing device 4Y, for example, a charge image developer containing at least yellow toner and carrier is stored. The yellow toner is agitated inside the developing device 4Y to be triboelectrically charged, has the same polarity (negative polarity) as the charge charged on the photoreceptor 1Y, and is held on the developing roller (an example of a developer holding member). Then, it is difficult for the surface of the photoreceptor 1Y to pass through the developing device 4Y, so that the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed using the yellow toner. The photoreceptor 1Y on which a yellow toner image is formed then travels at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

[0312] When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image, so that the toner image on the photoreceptor 1Y is transferred to the intermediate transfer belt 20. The transfer bias applied at this time is a polarity (+) opposite to the polarity (-) of the toner. In the first unit 10Y, it is controlled by a control unit (not shown) to be, for example, +10 μA.

[0313] On the other hand, the toner remaining on the photoreceptor 1Y is removed by the photoreceptor cleaning device 6Y and recovered.

[0314] The primary transfer bias applied to the primary transfer rollers 5M, 5C, 5K after the second unit 10M is also controlled according to the first unit.

[0315] In this way, the intermediate transfer belt 20 on which the yellow toner image is transferred in the first unit 10Y is sequentially conveyed through the second unit to the fourth unit 10M, 10C, 10K, and the toner images of various colors are superimposed for multi-transfer.

[0316] The intermediate transfer belt 20 on which a toner image of four colors is multi-transferred through the first unit to the fourth unit reaches the secondary transfer section including the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt, and the secondary transfer roller (an example of a secondary transfer member) 26 disposed on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording paper (an example of a recording medium) P is supplied to the gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are in contact via a supply mechanism at a predetermined time point, and a secondary transfer bias is applied to the support roller 24. The transfer bias applied at this time is a (-) polarity that is the same polarity as the polarity (-) of the toner. The electrostatic force acting from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, thereby transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined based on the resistance detected by a resistance detection member (not shown) that detects the resistance of the secondary transfer section and is voltage-controlled.

[0317] After that, the recording paper P is fed into the crimping section (clamping section) of a pair of fixing rollers in the fixing device (an example of a fixing member) 28, and the toner image is fixed onto the recording paper P, thereby forming a fixed image.

[0318] As the recording paper P for transferring the toner image, for example, ordinary paper used in electrophotographic copiers, printers, etc. can be cited. As the recording medium, in addition to the recording paper P, OHP sheets, etc. can also be cited.

[0319] In order to further improve the smoothness of the surface of the fixed image, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper obtained by coating the surface of ordinary paper with resin or the like, copperplate paper for printing, etc. can be preferably used.

[0320] After the fixing of the color image is completed, the recording paper P is carried out toward the discharge section, and thus a series of color image forming operations are completed.

[0321] <Processing Cartridge>

[0322] The processing cartridge of the present embodiment will be described.

[0323] The processing cartridge of the present embodiment is a processing cartridge that is detachably mounted in the image forming apparatus: it includes a developing member that houses the electrostatic charge image developer of the present embodiment and develops the electrostatic charge image formed on the surface of the image holding body into a toner image.

[0324] The processing cartridge of the present embodiment is not limited to the above configuration, and may also be configured as follows: including a developing member and at least one selected from other members such as an image holding body, a charging member, an electrostatic charge image forming member, and a transfer member as needed.

[0325] Hereinafter, an example of the processing cartridge of the present embodiment is shown, but it is not limited thereto. In the following description, the main parts shown in Figure 2 will be described, and the description of other parts will be omitted.

[0326] Figure 2 is a schematic configuration diagram showing the processing cartridge of the present embodiment.

[0327] Figure 2 The processing cartridge 200 shown, for example, uses a frame 117 including a mounting rail 116 and an opening 118 for exposure to integrally combine and hold a photoreceptor 107 (an example of an image holding member), a charging roller 108 (an example of a charging member) provided around the photoreceptor 107, a developing device 111 (an example of a developing member), and a photoreceptor cleaning device 113 (an example of a cleaning member), so as to be made into a cartridge.

[0328] Figure 2 In it, 109 represents an exposure device (an example of an electrostatic latent image forming member), 112 represents a transfer device (an example of a transfer member), 115 represents a fixing device (an example of a fixing member), and 300 represents a recording paper (an example of a recording medium).

[0329] [Example]

[0330] Hereinafter, the embodiments of the invention will be described in detail by way of examples, but the embodiments of the invention are not limited by any of these examples. In the following description, unless otherwise specified, "parts" and "%" are based on mass.

[0331] [Production of amorphous resin particle dispersion liquid (aHB-1)]

[0332] The inside of a four-necked flask equipped with a nitrogen inlet tube, a stirring device, and a temperature sensor was purged with nitrogen, and 5670 parts of polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, 585 parts of polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, 2450 parts of terephthalic acid, 44 parts of di(2-ethylhexanoic acid), and 100 parts of vinyl alcohol were put in. While stirring, the temperature was raised to 235 °C in a nitrogen atmosphere and maintained for 5 hours. Subsequently, the pressure inside the flask was reduced and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, it was cooled to 190 °C, 42 parts of fumaric acid and 207 parts of trimellitic acid were added, and after maintaining at a temperature of 190 °C for 2 hours, the temperature was raised to 210 °C over 2 hours. Subsequently, the pressure inside the flask was reduced and maintained at 8.0 kPa for 4 hours to obtain an amorphous polyester resin A (polyester segment). Subsequently, 857 parts of the amorphous polyester resin A were put into a four-necked flask equipped with a condenser tube, a stirring device, and a temperature sensor, and stirred at a stirring speed of 200 rpm in a nitrogen atmosphere.

[0333] Subsequently, as addition polymerizable monomers, 60 parts of styrene, 60 parts of ethyl acrylate and 500 parts of ethyl acetate were added and mixed for 30 minutes. Subsequently, 6 parts of a nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation), 40 parts of a 15% aqueous solution of sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neoperex G-15, manufactured by Kao Corporation) and 233 parts of 5% potassium hydroxide were added, and the temperature was raised to 95°C with stirring for melting, and mixed at 95°C for 2 hours to obtain a resin mixture solution. Subsequently, 1145 parts of deionized water was added dropwise to the resin mixture solution at a rate of 6 parts per minute with stirring to obtain an emulsion. Subsequently, the obtained emulsion was cooled to 25°C, passed through a 200-mesh wire mesh, and deionized water was added to prepare a solid content of 20% to obtain an amorphous resin particle dispersion (aHB-1).

[0334] The amorphous resin particle dispersion (aHB-1) is a dispersion in which particles of a mixed amorphous resin are dispersed. In the mixed amorphous resin contained in the amorphous resin particle dispersion (aHB-1), the mass ratio of the styrene-acrylic acid segment to the polyester segment (styrene-acrylic acid segment: polyester segment) is 10:90, the weight average molecular weight is 16,000, and the glass transition temperature is 62°C.

[0335] [Preparation of amorphous resin particle dispersion (aHB-2)]

[0336] The same procedure as for the preparation of the amorphous resin particle dispersion (aHB-1) was carried out, except that 6 parts of the nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation) was changed to 6 parts of an anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to obtain an amorphous resin particle dispersion (aHB-2).

[0337] The amorphous resin particle dispersion (aHB-2) is a dispersion in which particles of a mixed amorphous resin are dispersed. In the mixed amorphous resin contained in the amorphous resin particle dispersion (aHB-2), the mass ratio of the styrene-acrylic acid segment to the polyester segment (styrene-acrylic acid segment: polyester segment) is 10:90, the weight average molecular weight is 16,000, and the glass transition temperature is 60°C.

[0338] [Preparation of amorphous resin particle dispersion (aPES)]

[0339] · 37 parts of ethylene glycol

[0340] · 65 parts of neopentyl glycol

[0341] · 32 parts of 1,9-nonanediol

[0342] · 96 parts of terephthalic acid

[0343] Load the said materials into a flask, raise the temperature to 200 °C over 1 hour. After confirming that uniform stirring has been achieved in the reaction system, add 1.2 parts of dibutyltin oxide. While distilling off the water produced, raise the temperature from the said temperature to 240 °C over 6 hours, and carry out a dehydration condensation reaction at 240 °C for 4 hours to obtain an amorphous polyester resin with an acid value of 9.4 mg KOH / g, a weight-average molecular weight of 13,000, and a glass transition temperature of 62 °C.

[0344] Subsequently, transfer the amorphous polyester resin to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g per minute in a molten state. For 0.37% dilute aqueous ammonia, while heating it to 120 °C using a heat exchanger, transfer it to Cavitron at a rate of 0.1 liter per minute simultaneously with the amorphous polyester resin. Operate Cavitron under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm 2 to obtain an aqueous dispersion of amorphous resin particles (aPES) with an average particle diameter of 160 nm and a solid content of 30%.

[0345] [Preparation of Crystalline Resin Particle Dispersion (cPES-1)]

[0346] · 81 parts of decanedioic acid

[0347] · 47 parts of hexanediol

[0348] Load the said materials into a flask, raise the temperature to 160 °C over 1 hour. After confirming that uniform stirring has been achieved in the reaction system, add 0.03 parts of dibutyltin oxide. While distilling off the water produced, raise the temperature from the said temperature to 200 °C over 6 hours, and carry out a dehydration condensation reaction at 200 °C for 4 hours to end the reaction. After cooling the reaction solution, carry out solid-liquid separation, and dry the obtained solid matter at 40 °C under a vacuum to obtain a crystalline polyester resin. The obtained crystalline polyester resin has a melting point of 64 °C and a weight-average molecular weight of 15,000.

[0349] · 50 parts of crystalline polyester resin

[0350] · Anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0351] 1.5 parts

[0352] · Non-ionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation)

[0353] 0.5 parts

[0354] · Ion-exchanged water 200 parts

[0355] Heat the above materials to 120 °C, disperse them sufficiently using a homogenizer (manufactured by IKE, Ultraturrax T50), then perform dispersion treatment using a pressure jet homogenizer, and recover when the volume average particle size reaches 180 nm. Thus, a crystalline resin particle dispersion (cPES-1) with a solid content of 20% is obtained.

[0356] [Preparation of crystalline resin particle dispersion (cPES-2)]

[0357] Perform the same as the preparation of the crystalline resin particle dispersion (cPES-1), except that 0.5 part of the non-ionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation) is not used, and correspondingly increase the amount of the anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (i.e., use 2 parts of the anionic surfactant) to obtain a crystalline resin particle dispersion (cPES-2).

[0358] [Preparation of crystalline resin particle dispersion (cHB-1)]

[0359] · Sebacic acid 730 parts

[0360] · Hexanediol 423 parts

[0361] · Vinyl alcohol 45 parts

[0362] Put the above materials into a flask, raise the temperature to 160 °C over 1 hour, confirm that uniform stirring is obtained in the reaction system, and then add 0.03 part of dibutyltin oxide. While distilling off the generated water, raise the temperature from the above temperature to 200 °C over 6 hours, and continue the dehydration condensation reaction at 200 °C for 4 hours to end the reaction. After cooling the reaction solution, perform solid-liquid separation, and dry the obtained solid at 40 °C under vacuum to obtain a crystalline polyester resin.

[0363] Subsequently, as addition polymerization monomers, 30 parts of styrene, 100 parts of ethyl acrylate, and 500 parts of ethyl acetate were added and mixed for 30 minutes. Subsequently, 7.5 parts of a nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation), 40 parts of a 15% aqueous solution of sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neoperex G-15, manufactured by Kao Corporation), and 233 parts of 5% potassium hydroxide were added, and the mixture was heated to 95°C with stirring to effect melting, and mixed at 95°C for 2 hours to obtain a resin mixture solution. Subsequently, 1145 parts of deionized water were added dropwise to the resin mixture solution at a rate of 6 parts per minute with stirring to obtain an emulsion. Subsequently, the obtained emulsion was cooled to 25°C, passed through a 200-mesh wire mesh, and deionized water was added to prepare a solid content of 20% to obtain a crystalline resin particle dispersion (cHB-1).

[0364] The crystalline resin particle dispersion (cHB-1) is a dispersion in which particles of a mixed crystalline resin are dispersed. In the mixed crystalline resin contained in the crystalline resin particle dispersion (cHB-1), the melting point is 68°C and the weight average molecular weight is 13,000.

[0365] [Preparation of Crystalline Resin Particle Dispersion (cHB-2)]

[0366] The preparation was carried out in the same manner as for the crystalline resin particle dispersion (cHB-1), except that the nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation) was not used, and correspondingly, an anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used to obtain a crystalline resin particle dispersion (cHB-2).

[0367] [Preparation of Release Agent Particle Dispersion (PF-1)]

[0368] · 50 parts of paraffin (HNP-9, manufactured by Nippon Seiro Co., Ltd.)

[0369] · Anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0370] 1.5 parts

[0371] · Nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation)

[0372] 0.5 parts

[0373] · 200 parts of ion-exchanged water

[0374] Heat the said material to 120°C, fully disperse it using a homogenizer (manufactured by IKA, Ultraturrax T50), and then perform dispersion treatment using a pressure ejection type homogenizer to obtain a release agent particle dispersion liquid (PF-1) with a volume average particle size of 200 nm and a solid content of 20%.

[0375] [Preparation of release agent particle dispersion liquid (PF-2)]

[0376] Perform in the same manner as the preparation of the release agent particle dispersion liquid (PF-1), without using 0.5 part of a nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation), and correspondingly increase the amount of an anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (i.e., use 2 parts of the anionic surfactant) to obtain the release agent particle dispersion liquid (PF-2).

[0377] [Preparation of release agent particle dispersion liquid (PE-1)]

[0378] · 50 parts of polyethylene wax (polywax 725, Baker Hughes)

[0379] · Anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0380] 1.5 parts

[0381] · Nonionic surfactant (trade name: Emulgen 147, manufactured by Kao)

[0382] 0.5 part

[0383] · 200 parts of ion-exchanged water

[0384] Heat the said material to 120°C, fully disperse it using a homogenizer (manufactured by IKE, Ultraturrax T50), and then perform dispersion treatment using a pressure ejection type homogenizer to obtain a release agent particle dispersion liquid (PE-1) with a volume average particle size of 200 nm and a solid content of 20%.

[0385] [Preparation of release agent particle dispersion liquid (PE-2)]

[0386] The production of the mold release agent particle dispersion (PE-1) was carried out in the same manner, except that 0.5 part of the nonionic surfactant (trade name: Emulgen 147, manufactured by Kao Corporation) was not used, and correspondingly, the amount of the anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was increased (i.e., 2 parts of the anionic surfactant were used) to obtain the mold release agent particle dispersion (PE-2).

[0387] [Production of the colorant particle dispersion (1)]

[0388] · 10 parts of a blue pigment (Pigment Blue 15:3, manufactured by Dainichi Seika Kogyo Co., Ltd.)

[0389] · Anionic surfactant (trade name: Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0390] 2 parts

[0391] · 80 parts of ion-exchanged water

[0392] The above materials were mixed and dispersed for 1 hour using a high-pressure impact disperser, Ultimizer (HJP30006, manufactured by Sugino Machine Ltd.) to obtain the colorant particle dispersion (1) having a volume average particle diameter of 180 nm and a solid content of 20%.

[0393] [Production of the toner particles (1) and the toner (1)]

[0394] · 150 parts of an amorphous resin particle dispersion (aHB-1)

[0395] · 50 parts of a crystalline resin particle dispersion (cPES-1)

[0396] · 35 parts of a mold release agent particle dispersion (PF-1)

[0397] · 25 parts of the colorant particle dispersion (1)

[0398] · 0.4 part of polyaluminum chloride

[0399] · 100 parts of ion-exchanged water

[0400] Put the said material into a round stainless-steel flask, mix and disperse it using a homogenizer (manufactured by IKE Co., Ultraturrax T50), and then heat the flask while stirring one side with a heating oil bath to 48 °C and keep it for 60 minutes. Subsequently, slowly add 70 parts of an amorphous resin particle dispersion (aHB-1). Then, adjust the pH value of the system to 8.0 using a 0.5 mol / L sodium hydroxide aqueous solution, seal the stainless-steel flask, and magnetically seal the stirring shaft seal. While continuously stirring, heat it to 90 °C and keep it for 30 minutes. Then, cool it at a cooling rate of 5 °C / min, filter and separate the solid components, wash them thoroughly with ion-exchanged water, and perform solid-liquid separation by suction filtration using a suction filter. Redisperse the solid components in ion-exchanged water at 30 °C, stir for 15 minutes at a rotation speed of 300 rpm and wash them. Furthermore, repeat the said washing operation 6 times. When the pH value of the filtrate becomes 7.54 and the conductivity becomes 6.5 μS / cm, perform solid-liquid separation by suction filtration using a suction filter and filter paper No. 5A. Continuously perform vacuum drying on the solid components for 24 hours to obtain color powder particles. The volume average particle size D50v of the color powder particles is 5.7 μm.

[0401] In the color powder particles, add silica particles with an average primary particle size of 40 nm and metatitanic acid compound particles (reaction product of metatitanic acid and isobutyltrimethoxysilane) whose surfaces have been hydrophobized with hexamethyldisilazane so that the coating rate on the surface of the color powder particles becomes 40%, and mix them using a Henschel mixer to obtain color powder (1).

[0402] [Production of Color Powder Particles (2) to Color Powder Particles (10) and Color Powder (2) to Color Powder (10)]

[0403] Proceed in the same manner as the production of color powder particles (1), but change the type of at least one of the amorphous resin particle dispersion, crystalline resin particle dispersion, and release agent particle dispersion as shown in Table 1 to respectively produce color powder particles (2) to color powder particles (10).

[0404] Use any one of color powder particles (2) to color powder particles (10) and proceed in the same manner as the production of color powder (1) to respectively produce color powder (2) to color powder (10).

[0405] [Table 1]

[0406]

[0407] [Production of Magnetic Particles (1)]

[0408] · 40 parts of phenol

[0409] · 60 parts of formaldehyde

[0410] · 400 parts of magnetite (volume average particle size 0.2 μm)

[0411] · 60 parts of ion-exchanged water

[0412] · 12 parts of ammonia water

[0413] Mix the above materials, while stirring, heat up to 85 °C and react for 4 hours to harden. Then, carry out cooling, solid-liquid separation by filtration and washing with ion-exchanged water. Then, heat up to 180 °C and dry. In this way, magnetic particles (1) in which magnetic bodies are dispersed in a phenol resin are obtained. In the magnetic particles (1), the volume average particle size D50v is 38 μm and the true specific gravity is 3.7 g / cm 3 .

[0414] [Production of Magnetic Particles (2)]

[0415] · Fe(OH) 3 1000 parts

[0416] · MnO 2 4.5 parts

[0417] · Mg(OH) 2 40 parts

[0418] Mix the above materials, add a dispersant, water, polyvinyl alcohol, and polymethyl methacrylate particles with a volume average particle size of 2 μm, and carry out mixing and stirring using zirconia beads with a medium diameter of 1 mm. Then, granulate and dry using a spray dryer to obtain a volume average particle size of 40 μm. The dried particles are calcined in a mixed environment of oxygen and nitrogen (adjusted so that the oxygen concentration becomes 1 vol%) at 1200 °C for 4 hours using an electric furnace. After calcination, through pulverization and classification, magnetic particles (2) are obtained. In the magnetic particles (2), the volume average particle size D50v is 38 μm and the true specific gravity is 3.4 g / cm 3 .

[0419] [Production of Magnetic Particles (3)]

[0420] · Fe(OH) 3 1000 parts

[0421] · MnO 2 4.5 parts

[0422] · Mg(OH) 2 40 parts

[0423] Mix the materials, add a dispersant, water, and polyvinyl alcohol, and perform mixing and stirring using zirconia beads with a medium diameter of 1 mm. Subsequently, use a spray dryer to granulate and dry the materials to achieve a volume average particle diameter of 39 μm. Calcinate the dried particles in a mixed environment of oxygen and nitrogen (adjusted so that the oxygen concentration is 1 vol%) at 1400 °C for 6 hours using an electric furnace. After calcination, perform pulverization and classification to obtain magnetic particles (3). Among the magnetic particles (3), the volume average particle diameter D50v is 38 μm, and the true specific gravity is 4.6 g / cm 3 .

[0424] [Preparation of Coating Composition (1)]

[0425] · Silicone resin solution (SR2410, Dow Corning Toray Silicone Co., Ltd.)

[0426] 100 parts

[0427] · Toluene 300 parts

[0428] Mix the materials to obtain coating composition (1).

[0429] [Preparation of Coating Composition (2)]

[0430] · Cyclohexyl methacrylate resin (weight average molecular weight 50,000) 36 parts

[0431] · Carbon black (manufactured by Cabot, VXC72) 4 parts

[0432] · Toluene 300 parts

[0433] Put the materials and glass beads (particle diameter 1 mm, same amount as toluene) into a sand mill (manufactured by Kansai Paint Co., Ltd.) and stir at a rotational speed of 1200 rpm for 30 minutes to obtain coating composition (2) with a solid content of 11%.

[0434] [Preparation of Resin-Coated Carrier (1)]

[0435] Load 1000 parts of magnetic particles (1) into a composite fluidized bed coating device MP01-SFP (Powrex). Under the conditions of a screen mesh of 0.5 mm, a rotating impeller of 1000 rpm, an exhaust air volume of 1.2 m 3 / min, a coating speed of 10 g / min, and a temperature of 80 °C, coat with coating composition (1) so that the coating rate becomes 98.5% to obtain resin-coated carrier (1).

[0436] [Production of Resin-Coated Carrier (2)]

[0437] It is carried out in the same manner as the production of carrier (1), where magnetic particles (1) are changed to magnetic particles (2), and the coating rate is changed to 97.0%, to obtain resin-coated carrier (2).

[0438] [Production of Resin-Coated Carrier (3)]

[0439] It is carried out in the same manner as the production of carrier (1), where magnetic particles (1) are changed to magnetic particles (3), and the coating rate is changed to 97.5%, to obtain resin-coated carrier (3).

[0440] [Production of Resin-Coated Carrier (4)]

[0441] It is carried out in the same manner as the production of carrier (1), where coating composition (1) is changed to coating composition (2), to obtain resin-coated carrier (4).

[0442] [Table 2]

[0443]

[0444] [Example 1]

[0445] The resin-coated carrier (1) and toner (1) are put into a V-type stirrer at a ratio of carrier:toner = 100:8 (mass ratio), and stirred for 20 minutes to obtain a developer.

[0446] [Examples 2 to 18]

[0447] It is carried out in the same manner as Example 1, where the combination of toner and resin-coated carrier is changed as described in Table 3 to obtain developers respectively.

[0448] [Comparative Examples 1 to 10]

[0449] It is carried out in the same manner as Example 1, where the combination of toner and resin-coated carrier is changed as described in Table 3 to obtain developers respectively.

[0450] [Performance Evaluation]

[0451] The developer of each example or each comparative example is put into the cyan developer of a modified machine of DocuCentre C400 manufactured by Fuji Xerox Co., Ltd. (an image forming apparatus capable of arbitrarily changing the printing speed and having a fixed circumferential speed ratio between the photoreceptor and the developer sleeve).

[0452] An image with a cyan concentration of 100% and a size of 5 cm square (referred to as "Print 1") is formed on a standard A4-sized paper under the environment of a temperature of 30°C and a relative humidity of 85%.

[0453] Subsequently, 100,000 cyan images with a density of 1% are continuously printed on a standard A4-sized paper under the environment of a temperature of 30°C and a relative humidity of 85%.

[0454] Then, an image with a cyan concentration of 100% and a size of 5 cm square (referred to as "Print 2") is formed on a standard A4-sized paper under the environment of a temperature of 30°C and a relative humidity of 85%.

[0455] Subsequently, the printing speed is halved, and 10 cyan images with a density of 1% are printed on a standard A4-sized paper under the environment of a temperature of 30°C and a relative humidity of 85%.

[0456] Then, an image with a cyan concentration of 100% and a size of 5 cm square (referred to as "Print 3") is formed on a standard A4-sized paper under the environment of a temperature of 30°C and a relative humidity of 85%.

[0457] The hue of the 5 cm square image is measured by a spectrophotometric color difference meter (manufactured by X-Rite Inc., RM200QC). The color difference ΔE between Print 1 and Print 2 (referred to as "ΔE1") and the color difference ΔE between Print 1 and Print 3 (referred to as "ΔE2") are calculated by the following formula.

[0458] [Equation 1]

[0459]

[0460] In the formula, L 1 , a 1 , b 1 are the L*, a*, and b* values of Print 1, and L 2 , a 2 , b 2 are the L*, a*, and b* values of Print 2 or Print 3.

[0461] {ΔE1 - ΔE2} is calculated based on ΔE1 and ΔE2, and its absolute value is used as an index of the concentration difference. The evaluation results are shown in Table 3.

[0462] A: |ΔE1 - ΔE2| is 0.5 or less.

[0463] B: |ΔE1 - ΔE2| exceeds 0.5 and is less than 1.0.

[0464] C: |ΔE1 - ΔE2| exceeds 1.0 and is less than 2.0.

[0465] D: |ΔE1 - ΔE2| exceeds 2.0.

[0466] [Table 3]

[0467]

[0468]

Claims

1. A static charge image developer, comprising: toner containing toner particles, the toner particles containing a binder resin, a release agent, and a nonionic surfactant; and A resin-coated carrier having magnetic particles and a resin layer coating the magnetic particles, with a true specific gravity of 3 g / cm 3 or more and 4 g / cm 3 or less. wherein the binder resin contains an amorphous modified polyester resin obtained by modifying an amorphous polyester resin with at least one of styrene and (meth)acrylate, wherein, relative to the content of the resin-coated carrier, the content of the nonionic surfactant is 0.5 ppm or more and 10 ppm or less on a mass basis.

2. The static charge image developer according to claim 1, wherein the binder resin contains at least one of a crystalline polyester resin and a crystalline modified polyester resin obtained by modifying a crystalline polyester resin with at least one of styrene and (meth)acrylate.

3. The static charge image developer according to claim 1, wherein the resin layer contains a silicone resin.

4. The static charge image developer according to claim 1, wherein the release agent contains paraffin.

5. The static charge image developer according to claim 1, wherein the nonionic surfactant is a compound having a polyoxyalkylene structure.

6. The static charge image developer according to claim 5, wherein the nonionic surfactant is a compound having a polyoxyethylene structure.

7. A processing cartridge detachably installed in an image forming apparatus, the processing cartridge includes a developing member that houses the static charge image developer according to claim 1 and develops a static charge image formed on the surface of an image holding body into a toner image by using the static charge image developer.

Images