Particles, toner, developer, image forming apparatus, and image forming method

Abstract

To provide particles that have a low environmental impact, excellent static charge stability over time, and excellent static charge stability even in high humidity environments. [Solution] A particle comprising a mother particle containing a resin mainly composed of polyester and an external additive, wherein the polyester contains at least one of polyethylene terephthalate and polybutylene terephthalate, the external additive is coated with a metal hydroxide, and when the resistance value of the external additive at 25°C and 50% humidity is R1 [logΩcm] and the resistance value of the mother particle is R2 [logΩcm], and when the resistance value of the external additive at 40°C and 70% humidity is R3 [logΩcm] and the resistance value of the mother particle is R4 [logΩcm], the particle satisfies R1 ≤ R2 and R3 ≤ R4.

Description

[Technical Field]

[0001] The present invention relates to particles, toner, developer, image forming apparatus, and image forming method. [Background technology]

[0002] Resin-containing particles are widely used as toner in image forming devices such as multifunction printers (MFPs) and printers in various locations, including offices. To reduce the environmental impact of toner, various measures are being considered, such as improving the low-temperature fixability of the toner itself to reduce power consumption, reducing energy consumption during manufacturing, using biomass-derived resins (plant-derived) as binder resins, and using recycled materials for binder resins. In particular, given the increasing importance of resource conservation, energy saving, and resource recycling, there is a growing demand for the use of recycled materials in binder resins.

[0003] For example, Patent Document 1 discloses toner particles containing a binder resin manufactured using recycled raw materials, comprising an amorphous polyester toner resin containing a depolymerized PET polyol, a depolymerized recycled PET polyol, a second amorphous resin containing a bio-based polyester or polyacid, and an arbitrary crystalline resin. [Overview of the project] [Problems that the invention aims to solve]

[0004] However, because the toner particles in Patent Document 1 contain polyethylene terephthalate, they are susceptible to problems such as poor electrostatic properties and increased hygroscopicity, which can affect the properties of the resin contained in the toner particles and lead to a deterioration in image quality.

[0005] One embodiment of the present invention aims to provide particles that have a low environmental impact, excellent static charge stability over time, and excellent static charge stability even in high humidity environments. [Means for solving the problem]

[0006] To solve the above problems, one embodiment of the present invention is: Particles comprising a mother particle containing a resin mainly composed of polyester, and an external additive, The polyester comprises at least one of polyethylene terephthalate and polybutylene terephthalate. The aforementioned external additive is coated with a metal hydroxide, At 25°C and 50% humidity, the resistance of the external additive is R1 [logΩcm], and the resistance of the parent particles is R2 [logΩcm]. When the resistance of the external additive is R3 [logΩcm] and the resistance of the parent particles is R4 [logΩcm] at 40℃ and 70% humidity, We provide a particle where R1 ≤ R2 and R3 ≤ R4. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide particles that have a low environmental impact, excellent static charge stability over time, and excellent static charge stability even in high humidity environments. [Brief explanation of the drawing]

[0008] [Figure 1] This is an example of an image forming apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below. However, the embodiments are not limited to the following description and can be modified as appropriate without departing from the spirit of the invention. Furthermore, in this specification, the "~" indicating a numerical range means that the values ​​before and after it are included as the lower and upper limits, respectively, unless otherwise specified.

[0010] Embodiments of the present invention will be described in detail below.

[0011] (particle) The particles of the present invention are Particles containing matrix particles containing a resin mainly composed of polyester and an external additive, The polyester includes at least one of polyethylene terephthalate and polybutylene terephthalate, The external additive is coated with a metal hydroxide, At 25 °C and 50% humidity, let the resistance value of the external additive be R1 [logΩcm] and the resistance value of the matrix particles be R2 [logΩcm], At 40 °C and 70% humidity, when the resistance value of the external additive is R3 [logΩcm] and the resistance value of the matrix particles is R4 [logΩcm], The particles are such that R1 ≤ R2 and R3 ≤ R4.

[0012] Such particles can provide particles with low environmental impact, excellent charge stability over time, and excellent charge stability even in a high-humidity environment. Further, by using such particles in image formation, an image with excellent quality can be stably provided.

[0013] <Matrix particles> The matrix particles contained in the particles of the present invention are mainly composed of polyester, and the polyester includes at least one of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). In this specification, "main component" means the component that is contained in the largest amount in terms of the molar ratio of the components contained.

[0014] <<Polyethylene terephthalate and polybutylene terephthalate>> Since the particles of the present invention contain at least one of polyethylene terephthalate and polybutylene terephthalate in the matrix particles, they may contain a biomass-derived resin instead of a petroleum-derived resin, and can be particles with low environmental impact.

[0015] There are no particular restrictions on the molecular weight distribution, composition, manufacturing method, or form of polyethylene terephthalate or polybutylene terephthalate used, and they can be appropriately selected according to the purpose. However, from the viewpoint of reducing the environmental impact, it is preferable to use recycled materials, off-spec fiber waste, or pellets, and it is even more preferable to use recycled materials processed into flakes.

[0016] There are no particular restrictions on the weight-average molecular weight (Mw) of polyethylene terephthalate or polybutylene terephthalate, and it can be appropriately selected depending on the purpose, but 30,000 to 100,000 is preferred.

[0017] The analytical and calculation methods for the polyethylene terephthalate and polybutylene terephthalate content in particles are not particularly limited, and general methods for calculating the amount of polyethylene terephthalate can be used. As an analytical and calculation method for the polyethylene terephthalate or polybutylene terephthalate content, for example, the particles can be separated by gel permeation chromatography (GPC), and the mass ratio of the constituent components of the particles can be calculated by using the analytical methods described later for each separated component.

[0018] Furthermore, quantitative analysis can also be performed by estimating the main components from the soft decomposition due to methylation of ester bonds in the particles using gas chromatography-mass spectrometry (GC / MS) at 300°C with a reaction reagent (10% tetramethylammonium hydroxide (TMAH) / methanol solution), and by drawing a calibration curve of total ion current chromatogram (TICC) intensity.

[0019] The separation of each component by GPC can be performed, for example, by the following method.

[0020] In GPC measurements using tetrahydrofuran (THF) as the mobile phase, the eluate is separated using a fraction collector or similar device, and the fraction corresponding to the desired molecular weight portion of the total integral of the elution curve is collected.

[0021] After concentrating and drying the eluate collected from these fractions using an evaporator or the like, the solid components are dissolved in a deuterated solvent such as deuterated chloroform or deuterated THF. 1 1H-NMR measurements are performed, and the ratio of constituent monomers in the resin in the eluted components is calculated from the integral ratio of each element.

[0022] Another method involves concentrating the eluate, hydrolyzing it with sodium hydroxide or the like, and then qualitatively and quantitatively analyzing the decomposition products using high-performance liquid chromatography (HPLC) or similar methods to calculate the constituent monomer ratios.

[0023] Furthermore, an example of a method for separating each component contained in particles when analyzing them is described in detail.

[0024] First, 1 g of particles is placed in 100 mL of THF, and a solution is obtained by stirring for 30 minutes at 25°C until the soluble components are dissolved. The solution is filtered through a membrane filter with a mesh size of 0.2 μm to obtain the THF-soluble components in the particles. Next, the sample dissolved in THF is injected into a gel permeation chromatography (GPC) machine capable of molecular weight measurement. Meanwhile, a fraction collector is placed at the eluate outlet of the GPC, and the eluate is collected at predetermined count intervals, obtaining eluate at 5% area percentage intervals from the start of elution (rise of the curve) on the elution curve. Next, for each eluate, 30 mg of the sample is dissolved in 1 mL of deuterated chloroform, and 0.05 vol% tetramethylsilane (TMS) is added as a reference substance. The solution is packed into a 5 mm diameter glass tube for NMR measurement, and a nuclear magnetic resonance spectrometer (e.g., JEOL Ltd. JNM-AL400) is used to perform 128 integrations at a temperature of 23°C to 25°C to obtain the spectrum. The monomer composition and proportions of polyethylene terephthalate and other elements contained in the particles can be determined from the peak integration ratio of the obtained spectrum.

[0025] There are no particular restrictions on the content of polyethylene terephthalate and polybutylene terephthalate, and they can be appropriately selected depending on the purpose. However, 5 to 70 parts by mass and 10 to 50 parts by mass are preferred per 100 parts by mass of the base particles. If the content of polyethylene terephthalate and polybutylene terephthalate is 5 parts by mass or more per 100 parts by mass of the base particles, the effect of reducing environmental impact is more easily achieved, and the particles can maintain uniform particle size. If it is 70 parts by mass or less, the effect of low-temperature fixation is more easily achieved. When the content of polyethylene terephthalate and polybutylene terephthalate is within the above more preferred range, it is advantageous in that it is possible to achieve both a reduction in the environmental impact of the particles and an improvement in particle size uniformity.

[0026] Furthermore, the mass ratio of polyethylene terephthalate and polybutylene terephthalate in the particles is preferably 5% to 70% of the total resin, more preferably 10% to less than 50%, and even more preferably 20% to less than 35%. When the mass ratio of polyethylene terephthalate and polybutylene terephthalate in the particles is 5% or more of the total resin, the effect of reducing environmental impact is more easily achieved and particle size uniformity can be ensured, and when it is 70% or less, the effect of low-temperature fixation is more easily achieved. When the mass ratio of polyethylene terephthalate and polybutylene terephthalate is within the above more preferred range, it is advantageous in that it is possible to achieve both a reduction in the environmental impact of the particles and an improvement in particle size uniformity.

[0027] The content of polyethylene terephthalate and polybutylene terephthalate relative to the total mass of the parent particles in the particles is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. When the content of polyethylene terephthalate and polybutylene terephthalate relative to the total mass of the particles is 30% by mass or more, particles with a higher effect in reducing environmental impact can be obtained.

[0028] The parent particles of the particles of the present invention preferably contain polyethylene terephthalate and polybutylene terephthalate, as well as at least one of amorphous resins, amorphous resins, and crystalline resins, and more preferably at least one of the amorphous resins, amorphous resins, and crystalline resins contains a biomass-derived resin. When the particles contain at least one of amorphous resins, amorphous resins, and crystalline resins, and at least one of the amorphous resins, amorphous resins, and crystalline resins contains a biomass-derived resin, it becomes easier to achieve a total content of 50% by mass or more of biomass-derived resin and polyethylene terephthalate and polybutylene terephthalate relative to the total mass of the particles, thus enabling the creation of particles with a lower environmental impact. Furthermore, the influence of the biomass-derived resin on the particle properties due to structural differences between biomass-derived resins and petroleum-derived resins can be reliably reduced, resulting in particles with better electrostatic stability, higher particle size uniformity, and the ability to more stably provide high-quality images.

[0029] Furthermore, in the resin contained in the particles of the present invention, radioactive carbon isotopes 14 The C concentration is preferably 10.8 pMC or higher. Radiocarbon isotope 14 A C concentration of 10.8 pMC or higher is preferable because it allows for the creation of particles with a lower environmental impact.

[0030] In this specification, polyethylene terephthalate and polybutylene terephthalate are not included in the term "amorphous resin."

[0031] <<Amorphous resin (prepolymer)>> From the viewpoint of improving low-temperature fixability, the particles of the present invention preferably contain at least one of an amorphous resin (prepolymer) and its elongated form.

[0032] Examples of reactive precursors for amorphous resins (prepolymers) include polyesters having groups that can react with active hydrogen groups.

[0033] Examples of groups that can react with active hydrogen groups include isocyanate groups, epoxy groups, carboxylic acids, and acid chloride groups. Among these, isocyanate groups are preferred because they can introduce urethane or urea bonds into amorphous polyester resins.

[0034] The reactive precursor of the amorphous resin (prepolymer) may have a branched structure conferred by at least one of a trivalent or higher alcohol and a trivalent or higher carboxylic acid.

[0035] Examples of polyester resins having isocyanate groups include reaction products of polyester resins having active hydrogen groups and polyisocyanates.

[0036] Polyester resins having active hydrogen groups can be obtained, for example, by polycondensation of a diol, a dicarboxylic acid, and at least one of a trivalent or higher alcohol and a trivalent or higher carboxylic acid. The trivalent or higher alcohol and the trivalent or higher carboxylic acid impart a branched structure to the polyester resin having isocyanate groups.

[0037] Examples of diols include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol; diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethyl Examples include diols having oxyalkylene groups such as ethylene glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; alicyclic diols to which alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide have been added; bisphenols such as bisphenol A, bisphenol F, and bisphenol S; and alkylene oxide adducts of bisphenols to which alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide have been added.

[0038] Among these, from the viewpoint of controlling the glass transition temperature (Tg) of the extended amorphous resin (prepolymer) to 20°C or below, it is preferable to use aliphatic diols having 3 to 10 carbon atoms, such as 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, and 3-methyl-1,5-pentanediol, and it is more preferable to use 50 mol% or more of the alcohol component in the resin. These diols may be used individually or in combination of two or more.

[0039] Furthermore, among the extended amorphous resins (prepolymers) mentioned above, those in which the reactive precursor of the amorphous resin (prepolymer) is polyester are referred to as amorphous polyester resin A.

[0040] <<<Amorphous polyester resin A>>> Amorphous polyester resin A has steric hindrance in its resin chains, which reduces its melt viscosity during fixing and makes it easier to achieve low-temperature fixing properties. For this reason, the main chain of the aliphatic diol preferably has a structure represented by the following general formula (1).

[0041] HO-(CR1R2)n-OH General formula (1) (However, in general formula (1), R1 and R2 each independently represent a hydrogen atom and an alkyl group having 1 to 3 carbon atoms. n represents an odd number from 3 to 9. In n repeating units, R1 and R2 may be the same or different.)

[0042] Here, the main chain of an aliphatic diol refers to the carbon chain connecting the two hydroxyl groups of the aliphatic diol in the shortest possible number of carbon atoms. When the number of carbon atoms in the main chain is odd, it is preferable because the crystallinity decreases due to the oddness. Furthermore, when there is at least one alkyl group with 1 to 3 carbon atoms in the side chain, it is even more preferable because the interaction energy between the main chain molecules decreases due to the stericity.

[0043] Examples of dicarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, dodecanedioic acid, maleic acid, and fumaric acid; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. Anhydrides, lower (C1-C3) alkyl esters, and halides of these dicarboxylic acids may also be used. Among these, aliphatic dicarboxylic acids with 4 to 12 carbon atoms are preferred from the viewpoint of controlling the glass transition temperature (Tg) of amorphous polyester resin A to 20°C or below, and it is more preferable to use them in amounts of 50% by mass or more of the carboxylic acid component in the resin. These dicarboxylic acids may be used individually or in combination of two or more.

[0044] Examples of trivalent or higher alcohols include trivalent or higher aliphatic alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol; trivalent or higher polyphenols such as trisphenol PA, phenol novolac, and cresol novolac; and alkylene oxide adducts of trivalent or higher polyphenols, such as those obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to trivalent or higher polyphenols.

[0045] Examples of trivalent or higher carboxylic acids include trivalent or higher aromatic carboxylic acids, with trimellitic acid and pyromellitic acid, which have 9 to 20 carbon atoms, being particularly preferred. Alternatively, their anhydrides, lower (1 to 3 carbon atoms) alkyl esters, and halides may also be used.

[0046] Examples of polyisocyanates include diisocyanates and isocyanates with a valency of three or higher.

[0047] There are no particular restrictions on the polyisocyanate, and it can be appropriately selected depending on the purpose. For example, 1,3- and / or 1,4-phenylenediisocyanate, 2,4- and / or 2,6-tolylenediisocyanate (TDI), crude TDI, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, crude diaminophenylmethane [a condensation product of formaldehyde and an aromatic amine (aniline) or a mixture thereof; diaminodiphenylmethane and a small amount (e.g., 5-20% by mass) of trifunctional or more]. Phosgenes of mixtures with polyamines: Aromatic diisocyanates such as polyallyl polyisocyanate (PAPI), 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m- and p-isocyanatophenylsulfonyl isocyanates; ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate Aliphatic diisocyanates such as isocyanates, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate; isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanato Examples include alicyclic diisocyanates such as ethyl)-4-cyclohexene-1,2-dicarboxylate and 2,5- and 2,6-norbornane diisocyanate; aromatic aliphatic diisocyanates such as m- and p-xylylene diisocyanate (XDI) and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI); trivalent or higher polyisocyanates such as lysine triisocyanate and diisocyanate-modified alcohols of trivalent or higher; and modified products of these isocyanates, which may be mixtures of two or more of these.Examples of modified isocyanates include modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, uretodione groups, uretoimine groups, isocyanurate groups, and oxazolidone groups.

[0048] <<Amorphous resin>> Examples of amorphous resins that may be included in the present invention include terpene resins and amorphous polyester resins, and amorphous polyester resins other than those described above are referred to as "amorphous polyester resin B".

[0049] <<<Amorphous polyester resin B>>> As the amorphous polyester resin B, linear polyester resin is preferred, and unmodified polyester resin is preferred. Note that "linear polyester" means "linear polyester," and "non-linear polyester" means "non-linear polyester."

[0050] Unmodified polyester resin is a polyester resin obtained using a polyhydric alcohol and a polyhydric carboxylic acid, such as a polyhydric carboxylic acid, polyhydric carboxylic acid anhydride, or polyhydric carboxylic acid ester, or a derivative thereof, and is not modified by an isocyanate compound or the like.

[0051] The amorphous polyester resin B is preferably free from urethane and urea bonds.

[0052] Amorphous polyester resin B contains a dicarboxylic acid component as a constituent, and it is preferable that the dicarboxylic acid component contains 50 mol% or more of terephthalic acid. This is advantageous in terms of heat resistance and storage properties.

[0053] Examples of polyhydric alcohols include diols.

[0054] Examples of diols include alkylene (2-3 carbon atoms) oxide (average number of added moles 1-10) adducts of bisphenol A such as polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2,2)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol, neopentyl glycol, propylene glycol; hydrogenated bisphenol A, and alkylene (2-3 carbon atoms) oxide (average number of added moles 1-10) adducts of hydrogenated bisphenol A. These may be used individually or in combination of two or more.

[0055] Among these, it is preferable that the contents include ethylene glycol and propylene glycol, and more preferably that the contents include plant-derived ethylene glycol and propylene glycol.

[0056] Examples of polycarboxylic acids include dicarboxylic acids.

[0057] Examples of dicarboxylic acids include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid; succinic acid substituted with C1-C20 alkyl groups or C2-C20 alkenyl groups such as dodecenyl succinic acid and octyl succinic acid; and modified purified rosin. Modified purified rosin modified with acrylic acid, fumaric acid, and maleic acid is preferred.

[0058] Among these, it is preferable to include succinic acid, a saturated aliphatic material derived from plants, and modified purified rosin. Being plant-derived enhances carbon neutrality. Saturated aliphatic materials have the effect of increasing the recrystallization properties of crystalline polyester resins, thereby increasing the aspect ratio of the crystalline polyester resin and improving low-temperature fixability.

[0059] These can be used individually or in combination of two or more.

[0060] Furthermore, for the purpose of adjusting the acid value and hydroxyl value, amorphous polyester resin B may contain at least one of a trivalent or higher carboxylic acid and a trivalent or higher alcohol at the end of its resin chain.

[0061] Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, or their acid anhydrides.

[0062] Examples of alcohols with a hydride of 3 or higher include glycerin, pentaerythritol, and trimethylolpropane.

[0063] There are no particular restrictions on the molecular weight of amorphous polyester resin B, and it can be appropriately selected depending on the purpose. In gel permeation chromatography (GPC) measurement, the weight-average molecular weight (Mw) of amorphous polyester resin B is preferably 3,000 to 10,000. Furthermore, the number-average molecular weight (Mn) of amorphous polyester resin B is preferably 1,000 to 4,000. The ratio Mw / Mn of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of amorphous polyester resin B is preferably 1.0 to 4.0.

[0064] When the weight-average molecular weight (Mw) or number-average molecular weight (Mn) of amorphous polyester resin B is above the lower limit, it is possible to suppress a decrease in the heat-resistant storage properties of the particles and their durability against stress such as agitation in the developing machine. When it is below the upper limit, it is possible to suppress an increase in the viscoelasticity of the particles when they melt and suppress a decrease in low-temperature fixability.

[0065] The weight-average molecular weight (Mw) of amorphous polyester resin B is more preferably 4,000 to 7,000. The number-average molecular weight (Mn) of amorphous polyester resin B is more preferably 1,500 to 3,000. The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of amorphous polyester resin B, Mw / Mn, is more preferably 1.0 to 3.5.

[0066] There are no particular restrictions on the acid value of amorphous polyester resin B, and it can be appropriately selected depending on the purpose, but 1 mg KOH / g to 50 mg KOH / g is preferred, and 5 mg KOH / g to 30 mg KOH / g is more preferred. When the acid value of amorphous polyester resin B is 1 mg KOH / g or higher, the particles tend to become negatively charged, and furthermore, when fixed to an image-forming medium such as paper, the affinity between the image-forming medium and the particles improves, and low-temperature fixation can be improved. When the acid value of amorphous polyester resin B is 50 mg KOH / g or lower, it is possible to suppress the decrease in charge stability, especially charge stability against environmental changes.

[0067] The hydroxyl value of amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 5 mg KOH / g or higher. A hydroxyl value of 5 mg KOH / g or higher in amorphous polyester resin B is preferable because it makes it easier to achieve uniform particle size of the matrix particles.

[0068] The glass transition temperature (Tg) of amorphous polyester resin B is preferably 40°C to 80°C, and more preferably 50°C to 70°C. A glass transition temperature (Tg) of amorphous polyester resin B of 40°C or higher provides sufficient heat resistance for particle storage and durability against stress such as agitation in the developing machine, as well as good filming resistance. A glass transition temperature (Tg) of amorphous polyester resin B of 80°C or lower allows for sufficient deformation due to heating and pressurization during particle fixing, resulting in good low-temperature fixing performance.

[0069] The molecular structure of amorphous polyester resin B can be confirmed by NMR measurements in solution or solid state, as well as by X-ray diffraction, GC / MS, LC / MS, and IR measurements. A simple method is infrared absorption spectroscopy, which can determine the molecular structure at 965±10 cm⁻¹. -1 and 990±10cm -1 One method involves detecting amorphous polyester resin B if it does not exhibit absorption based on δCH (out-of-plane angular bending vibration) of the olefin.

[0070] The content of amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but 50 to 90 parts by mass and more preferably 60 to 80 parts by mass per 100 parts by mass of particles. When the content of amorphous polyester resin B is 50 parts by mass or more per 100 parts by mass of particles, deterioration of the dispersibility of colorants and release agents in the particles can be suppressed, and the occurrence of image fogging and distortion can be suppressed. When the content of amorphous polyester resin B is 90 parts by mass or less per 100 parts by mass of particles, the decrease in the content of crystalline polyester resin C and amorphous polyester resin B, which will be described later, can be suppressed, thereby suppressing a decrease in low-temperature fixability. When the content of amorphous polyester resin B is within the above more preferred range, it is advantageous in that it is excellent in both high image quality and low-temperature fixability.

[0071] <<Crystalline resin>> From the viewpoint of improving low-temperature fixability, the particles of the present invention preferably contain a crystalline resin.

[0072] As long as the crystalline resin is crystalline, there are no particular restrictions, and it can be appropriately selected according to the purpose. Examples include polyester resin, polyurethane resin, polyurea resin, polyamide resin, polyether resin, vinyl resin, and modified crystalline resin. These may be used individually or in combination of two or more.

[0073] In this invention, the polyester resin used as the crystalline resin is referred to as "crystalline polyester resin C". The crystalline polyester resin C will be described below.

[0074] <<<Crystalline polyester resin C>>> Crystalline polyester resin C exhibits thermal melting properties that show a rapid change in viscosity near the fixing start temperature due to its high crystallinity.

[0075] By using a crystalline polyester resin C with such properties together with an amorphous polyester resin B, particles with good heat resistance and low-temperature fixation properties can be obtained. For example, by using amorphous polyester resin B and crystalline polyester resin C together, the crystalline properties of the crystalline polyester resin C provide good heat resistance until just before the melting temperature. At the melting temperature, the crystalline polyester resin C melts, causing a rapid decrease in viscosity (sharp melt property). Consequently, it becomes compatible with the amorphous polyester resin B, and the rapid decrease in viscosity of both allows for good fixation.

[0076] Crystalline polyester resin C is obtained from a polyhydric alcohol and a polyhydric acid or its derivative, such as a polyhydric carboxylic acid, polyhydric carboxylic acid anhydride, or polyhydric carboxylic acid ester.

[0077] In this embodiment, crystalline polyester resin C refers to a resin obtained using a polyhydric alcohol and a polyhydric acid such as a polyhydric carboxylic acid, polyhydric acid anhydride, or polyhydric acid ester, or a derivative thereof, as described above. Modified polyester resins, such as prepolymers, and resins obtained by crosslinking and / or stretching the prepolymer, do not belong to crystalline polyester resin C.

[0078] -Polyhydric alcohols- There are no particular restrictions on polyhydric alcohols; they can be appropriately selected depending on the purpose. Examples include diols and alcohols with a hydride of three or higher.

[0079] Examples of diols include saturated aliphatic diols. Examples of saturated aliphatic diols include linear saturated aliphatic diols and branched saturated aliphatic diols, but among these, linear saturated aliphatic diols are preferred, and linear saturated aliphatic diols with 2 to 12 carbon atoms are more preferred. When the saturated aliphatic diol is a linear saturated aliphatic diol, the crystallinity of the crystalline polyester resin is less likely to decrease, and the melting point is less likely to decrease. In addition, when the saturated aliphatic diol has 2 to 12 carbon atoms, it is easy to obtain practical materials.

[0080] Examples of saturated aliphatic diols include 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, and 1,14-eicosandecanediol. Among these, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred because they easily increase the crystallinity of crystalline polyester resin C and improve its sharp melt properties.

[0081] Examples of trivalent or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used individually or in combination of two or more.

[0082] -Polyhydric carboxylic acids- There are no particular restrictions on polycarboxylic acids, and they can be appropriately selected depending on the purpose. Examples include divalent carboxylic acids and trivalent or higher carboxylic acids.

[0083] Examples of divalent carboxylic acids include saturated aliphatic dicarboxylic acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, superiric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid; and others. Furthermore, there are anhydrides of these and their lower (carbon) compounds. Alkyl esters are also an option. Among these, saturated aliphatic esters with 12 or fewer carbon atoms, derived from plants, are preferred from the viewpoint of carbon neutrality.

[0084] Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, and their anhydrides and lower (1-3 carbon atoms) alkyl esters.

[0085] These may be used individually or in combination of two or more types.

[0086] The crystalline polyester resin C is preferably composed of a linear saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and a linear saturated aliphatic diol having 2 to 12 carbon atoms. As a result, the crystalline polyester resin C has high crystallinity and excellent sharp melt properties, and can exhibit excellent low-temperature fixation. Furthermore, as a method for controlling the crystallinity and softening point of the crystalline polyester resin C, when synthesizing the crystalline polyester resin C, at least one of the following is performed: "adding a trivalent or higher polyhydric alcohol such as glycerin to the alcohol component" and "adding a trivalent or higher polyhydric carboxylic acid such as trimellitic anhydride to the acid component," and a nonlinear polyester or the like is designed and used after condensation polymerization.

[0087] The molecular structure of crystalline polyester resin C can be confirmed by NMR measurements in solution and solid state, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurements, etc. However, a simple method is to use infrared absorption spectroscopy, which is 965±10 cm⁻¹. -1 Alternatively, 990±10cm -1 Examples include those that have absorption based on δCH (out-of-plane bending vibration) of olefins.

[0088] Regarding the molecular weight of crystalline polyester resin C, those with a sharp molecular weight distribution as determined by GPC and low molecular weight exhibit excellent low-temperature fixation, while those with a high proportion of low molecular weight components have poor heat resistance and storage properties. From this perspective, it is preferable that the molecular weight distribution of the soluble o-dichlorobenzene in crystalline polyester resin C, as determined by GPC, shows a peak position in a molecular weight distribution graph with log(M) on the x-axis and mass% on the y-axis in the range of 3.5 to 4.0, with a peak width at half maximum of 1.5 or less. It is also preferable that the weight-average molecular weight (Mw) is 3,000 to 30,000, the number-average molecular weight (Mn) is 1,000 to 10,000, and the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), Mw / Mn, is 1 to 10. Furthermore, it is even more preferable that the weight-average molecular weight (Mw) is 5,000 to 15,000, the number-average molecular weight (Mn) is 2,000 to 10,000, and Mw / Mn is 1 to 5.

[0089] From the viewpoint of affinity between the resin and the image-forming medium such as paper, the acid value of crystalline polyester resin C is preferably 5 mg KOH / g or higher in order to achieve the desired low-temperature fixation. For the production of fine particles by the phase inversion emulsification method, the acid value of crystalline polyester resin C is more preferably 7 mg KOH / g or higher. On the other hand, to improve hot offset properties, the acid value of crystalline polyester resin C is preferably 45 mg KOH / g or lower.

[0090] Furthermore, the hydroxyl value of the crystalline polyester resin C is preferably 0 to 50 mg KOH / g, and more preferably 5 to 50 mg KOH / g, in order to achieve the required low-temperature fixability and good electrostatic properties.

[0091] Furthermore, in the particles of the present invention, it is preferable that the parent particles contain 0.05% to 1% by mass of a divalent metal. When the parent particles contain 0.05% to 1% by mass of a divalent metal, the fine particles can be aggregated mildly when the metal salt is used to agglomerate the raw material fine particles during the manufacturing process, resulting in parent particles with a good particle size distribution and high particle size uniformity.

[0092] Furthermore, in the particles of the present invention, the parent particles preferably contain magnesium as the divalent metal, and more preferably contain 0.1% to 0.5% by mass of magnesium in the parent particles. This makes it possible to reliably obtain particles with an even better particle size distribution and high particle size uniformity.

[0093] In the particles of the present invention, the parent particles preferably contain sodium, and more preferably contain more than 0.05% by mass of sodium. This ensures that particles with an even better particle size distribution and high particle size uniformity can be reliably obtained.

[0094] Furthermore, in the particles of the present invention, the parent particles preferably contain magnesium and sodium, and more preferably contain more magnesium than sodium. This makes it easier to agglomerate the raw material fine particles using a metal salt when manufacturing the particles, thus more reliably obtaining particles with a better particle size distribution and even greater uniformity in particle size.

[0095] <Resin fine particles> The particles of the present invention may also include resin fine particles. When the particles of the present invention include resin microparticles, the resin microparticles adhere to the surface of the matrix particles, and the particle has a "core" with the matrix particles as the core layer and a "shell" with the resin microparticles as the shell layer, forming a "core-shell structure". In the core-shell structure described above, the surface of the core layer may be completely covered by the shell layer, or it may not be completely covered by the shell layer. Examples of configurations in which the surface of the core layer is not completely covered by the shell layer include configurations in which the core layer is covered by the shell layer in a mesh-like manner, and configurations in which the core layer is partially exposed from the shell layer.

[0096] From the viewpoint of reducing environmental impact, the aforementioned resin fine particles preferably contain at least one of polyethylene terephthalate and polybutylene terephthalate. There are no particular restrictions on the molecular weight distribution, composition, manufacturing method, or form of polyethylene terephthalate or polybutylene terephthalate used, and they can be appropriately selected according to the purpose. However, from the viewpoint of reducing the environmental impact, it is preferable to use recycled materials, off-spec fiber waste, or pellets, and it is even more preferable to use recycled materials processed into flakes.

[0097] The resin fine particles may also contain a resin obtained by a condensation reaction between acid monomer units and alcohol monomer units.

[0098] The acid monomers and units mentioned above are preferably monomers having a carboxyl group, such as adipic acid, terephthalic acid, succinic acid, and rosinic acid.

[0099] The alcohol monomer units are preferably monomers having a hydroxyl group, such as Bis-A-EO2mol adduct, Bis-A-PO2mol adduct, 1,2-propanediol, trimethylolpropane, glycerin, neopentyl glycol, and the like.

[0100] <External additives> The particles of the present invention contain an external additive, the external additive being coated with a metal hydroxide.

[0101] The particles of the present invention include an external additive coated with a metal hydroxide. When the resistance of the external additive coated with a metal hydroxide is R1 [logΩcm] and the resistance of the parent particles is R2 [logΩcm] at 25°C and 50% humidity, and when the resistance of the external additive coated with a metal hydroxide is R3 [logΩcm] and the resistance of the parent particles is R4 [logΩcm] at 40°C and 70% humidity, then R1 ≤ R2 and R3 ≤ R4. By setting R1 ≤ R2, particles can be made that easily accumulate and retain charge on their surface. Furthermore, by setting R3 ≤ R4, particles can be made that easily accumulate and retain charge on their surface even under high temperature and high humidity conditions.

[0102] In the particles of the present invention, since the external additive is coated with a metal hydroxide, intermolecular interactions can be more easily generated between the surface of the parent particles or resin microparticles and the hydroxyl groups present on the surface of the external additive, thereby more reliably suppressing the release of the external additive from the parent particles or resin microparticles.

[0103] Furthermore, generally, under high temperature and high humidity conditions, the resistance of inorganic external additives increases, while the resistance of the moisture-absorbing resin contained in the parent particles decreases. However, by having the external additive coated with a metal hydroxide, the temperature and humidity dependence of the resistance value of the external additive can be controlled even under high temperature and high humidity conditions, and R1 ≤ R2 and R3 ≤ R4 can be maintained. The external additive coated with a metal hydroxide preferably contains an inorganic substance containing silica or a metal oxide, and it is more preferable that the surface of the silica-containing inorganic substance or metal oxide is coated with a metal hydroxide.

[0104] The resistance value R1 [logΩcm] is preferably between 9.0 and 11.0. If R1 is 9.0 or higher, it is easier to retain the accumulated charge, and if it is 11.0 or lower, it is easier to accumulate charge on the particle surface.

[0105] The resistance value R2 [logΩcm] is preferably 11.5 or less, and more preferably 11.3 or less. When R2 is 11.5 or less, charge is easily accumulated on the particle surface.

[0106] The resistance value R3 [logΩcm] is preferably 8.0 to 10.8, and more preferably 8.5 to 10.5. When R3 is 8.0 or higher, it is easier to retain the accumulated charge under high temperature and high humidity conditions, and when it is 10.8 or lower, it is easier to accumulate charge on the particle surface under high temperature and high humidity conditions.

[0107] The resistance value R4 [logΩcm] is preferably 10.0 to 10.8, and more preferably 10.4 to 10.7. When R4 is 10.0 or higher, it is easier to retain the accumulated charge under high temperature and high humidity conditions, and when it is 10.8 or lower, it is easier to accumulate charge on the particle surface under high temperature and high humidity conditions.

[0108] The external additive coated with a metal hydroxide may be placed on the surface of the matrix particles, on the surface of the resin microparticles, or on the surface of the matrix particles that exist between the resin microparticles.

[0109] There are no particular restrictions on the inorganic material containing silica, and it can be appropriately selected depending on the purpose. Examples include silicon dioxide (silica) and silicone oil.

[0110] There are no particular restrictions on the metal oxides used, and they can be appropriately selected depending on the purpose. Examples include titanium oxide, aluminum oxide, iron oxide, copper oxide, zinc oxide, tin oxide, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, and zirconium oxide.

[0111] Among these, silica and titanium dioxide are preferred from the viewpoint of adhesion to the matrix particles and resin fine particles, with silica being more preferred.

[0112] Examples of the aforementioned metal hydroxides include aluminum hydroxide, magnesium hydroxide, zinc hydroxide, and copper hydroxide. These may be used individually or in combination.

[0113] From the viewpoint of improving excellent electrostatic stability and electrostatic rise, it is preferable that the outermost surface of the external additive is hydrophobized with a silane or the like.

[0114] As silane agents, silane coupling agents containing alkylsilanes such as isobutylsilane, methyltrimethoxysilane, methyltriethoxysilane, and octyltrimethoxysilane are preferred.

[0115] The external additive coated with a metal hydroxide, whose outermost surface is hydrophobically treated with a silane agent or the like, can be obtained by treating hydrophilic inorganic fine particles serving as the external additive with a silane coupling agent containing an alkylsilane.

[0116] The average particle size of the external additive coated with a metal hydroxide is not particularly limited and can be appropriately selected according to the purpose. However, the average particle size of the primary particles is preferably 1 nm to 200 nm, more preferably 10 nm to 150 nm. If the average particle size of the external additive is within the above preferred range, it is possible to make it difficult for the external additive to be buried in the base particles so that the function of the external additive can be effectively exerted, and it is possible to suppress uneven damage to the surface of the electrostatic latent image carrier.

[0117] Further, as the external additive coated with a metal hydroxide, it is preferable to contain at least one kind having an average primary particle size of 1 nm to 30 nm and at least one kind having an average primary particle size of 50 nm to 200 nm. When containing those having an average primary particle size of 1 nm to 30 nm, the surface coverage rate by the metal hydroxide becomes high and the charge stability is excellent. When containing those having an average primary particle size of 50 nm to 200 nm, it becomes easier to be blocked by the blade, and filming and cleaning are improved.

[0118] The specific surface area of the external additive coated with a metal hydroxide by the BET method is preferably 20 m 2 / g to 500 m 2 / g, more preferably 100 m 2 / g to 400 m 2 [[ID=2)1]] / g, and even more preferably 200 m 2 / g to 300 m 2 / g.

[0119] The content of the external additive coated with a metal hydroxide in the particles of the present invention is not particularly limited and can be appropriately selected according to the purpose. However, with respect to 100 parts by mass of the base particles, 0.5 parts by mass to 6.0 parts by mass is preferable, and 1.0 parts by mass to 4.0 parts by mass is more preferable.

[0120] <Other external additives> Other external additives besides those coated with the above-mentioned metal hydroxides include inorganic fine particles, polymer fine particles, and the like. The other external additives preferably contain two types of fine particles: fine particles A of 100 nm or larger and fine particles B of 10 to 50 nm, and the content ratio of fine particles A to fine particles B is preferably 0.5 to 1.4.

[0121] Other inorganic fine particles used as external additives include, for example, silica, alumina, fatty acid metal salts (e.g., zinc stearate, aluminum stearate, etc.), metal oxides (e.g., titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, aluminum oxide, iron oxide, copper oxide, zinc oxide, tin oxide, antimony oxide), silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. Among these, silica, alumina, and titanium oxide are particularly preferred.

[0122] Furthermore, for other external additives, inorganic fine particles are preferably surface-treated with a hydrophobic treatment agent, as this suppresses deterioration of flow properties and electrostatic properties even under high humidity conditions. Preferred hydrophobic treatment agents include, for example, silane coupling agents such as methyltrimethoxysilane, methyltriethoxysilane, and octyltrimethoxysilane, silylating agents, silane coupling agents having alkyl fluoride compounds, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils.

[0123] Other polymer-based microparticles used as external additives include, for example, polymer particles made from polystyrene, fluoropolymers, methacrylate esters, acrylic ester copolymers, polycondensation systems such as silicone, benzoguanamine, and nylon, and thermosetting resins, obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization.

[0124] Other external additives may be placed on the surface of the matrix particles, on the surface of the resin microparticles, or on the surface of the matrix particles that exist between the resin microparticles.

[0125] Examples of commercially available titanium dioxide nanoparticles include P-25 (manufactured by Nippon Aerosil Co., Ltd.), STT-30 (manufactured by Titanium Industry Co., Ltd.), STT-65C-S (manufactured by Titanium Industry Co., Ltd.), TAF-140 (manufactured by Fuji Titanium Industry Co., Ltd.), MT-150W (manufactured by Teika Co., Ltd.), MT-500B (manufactured by Teika Co., Ltd.), MT-600B (manufactured by Teika Co., Ltd.), and MT-150A (manufactured by Teika Co., Ltd.).

[0126] Examples of hydrophobized titanium oxide nanoparticles include T-805 (manufactured by Nippon Aerosil Co., Ltd.), STT-30A (manufactured by Titanium Industry Co., Ltd.), STT-65S-S (manufactured by Titanium Industry Co., Ltd.), TAF-500T (manufactured by Fuji Titanium Industry Co., Ltd.), TAF-1500T (manufactured by Fuji Titanium Industry Co., Ltd.), MT-100S (manufactured by Teika Co., Ltd.), MT-100T (manufactured by Teika Co., Ltd.), and IT-S (manufactured by Ishihara Sangyo Co., Ltd.).

[0127] Furthermore, other external additives may be fine particles treated with silicone oil, and if necessary, silicone oil-treated oxide fine particles and silicone oil-treated inorganic fine particles, which are obtained by heating to form fine particles, are also preferred.

[0128] Examples of silicone oils that can be used include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, epoxy / polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic / methacrylic-modified silicone oil, and α-methylstyrene-modified silicone oil.

[0129] Examples of inorganic fine particles include silica, aluminum oxide, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, silica and titanium dioxide are particularly preferred.

[0130] There are no particular restrictions on the content of other external additives, and they can be appropriately selected depending on the purpose, but 0.1% to 5% by mass in the particles is preferred, and 0.3% to 3% by mass is more preferred.

[0131] There are no particular restrictions on the average particle size of the primary particles of other external additives, and they can be appropriately selected depending on the purpose, but 10 nm to 200 nm is preferred, and 10 nm to 100 nm is more preferred. If the particle size is 10 nm or larger, the other external additives are less likely to be embedded in the matrix particles, and their functions are more easily exerted, and if the particle size is 200 nm or smaller, the surface of the electrostatic latent image carrier is less likely to be damaged.

[0132] <Other ingredients> The particles of the present invention may contain other components besides those mentioned above. Examples of other components include mold release agents, colorants, charge control agents, cleaning properties enhancers, and magnetic materials.

[0133] <<Release agent>> There are no particular restrictions on the release agent, and it can be appropriately selected depending on the purpose, but a low-melting-point release agent with a melting point of 50°C to 120°C is preferred. Low-melting-point release agents, when dispersed with the resin, effectively act as a release agent at the interface between the fixing roller and the particles, thereby providing good hot offset even when no release agent is applied to the fixing roller.

[0134] Suitable release agents include, for example, waxes and waxes. Examples of waxes and waxes include natural waxes, synthetic hydrocarbon waxes, and synthetic waxes. Examples of natural waxes include plant-based waxes such as carnauba wax, cotton wax, wood wax, and rice wax; animal-based waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cerucine; and petroleum waxes such as paraffin, microcrystalline, and petrolatum. In addition to these natural waxes, examples of synthetic hydrocarbon waxes include Fischer-Tropsch wax and polyethylene wax, and examples of synthetic waxes include esters, ketones, and ethers. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride, and chlorinated hydrocarbons; homopolymers or copolymers of polyacrylates such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate, which are low molecular weight crystalline polymer resins (for example, copolymers of n-stearyl acrylate and ethyl methacrylate); and crystalline polymers having long alkyl groups in their side chains may also be used. These may be used individually or in combination of two or more.

[0135] From the perspective of reducing environmental impact, plant-based waxes are preferable.

[0136] There are no particular restrictions on the melting point of the release agent, and it can be appropriately selected depending on the purpose, but 50°C to 120°C is preferred, and 60°C to 90°C is more preferred. If the melting point is 50°C or higher, it is possible to prevent the release agent from adversely affecting the heat resistance of storage, and if it is 120°C or lower, it is possible to effectively prevent the problem of cold offset occurring during fixing at low temperatures. The melt viscosity of the release agent, measured at a temperature 20°C higher than the melting point of the release agent, is preferably 5 cps to 1,000 cps, and more preferably 10 cps to 100 cps. If the melt viscosity is 5 cps or higher, it is possible to prevent a decrease in release properties, and if it is 1,000 cps or lower, the effects of hot offset resistance and low-temperature fixing properties can be fully exhibited. There are no particular restrictions on the content of the release agent in the particles, and it can be appropriately selected depending on the purpose, but 0% to 40% by mass is preferred, and 3% to 30% by mass is more preferred.

[0137] <<Coloring agent>> Known dyes and pigments can be used as colorants, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow -, Bengara, Red lead, Red lead, Cadmium red, Cadmium mercury red, Antimony red, Permanent Red 4R, Para red, Faisey red, Parachlor orthonitroaniline red, Risol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, POG Mentoscarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinon Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine, Prussian Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake,Phthalocyanine green, anthraquinone green, titanium dioxide, zinc oxide, lithobone, and mixtures thereof can be used.

[0138] <<Static Control Agent>> For the charge control agent, a general charge control agent can be used. Examples of charge control agents include nigrosine-based dyes, triphenylmethane-based dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine-based dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, elemental or compound phosphorus, elemental or compound tungsten, fluorine-based surfactants, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, these include Bontron 03 (a nigrosine-based dye), Bontron P-51 (a quaternary ammonium salt), Bontron S-34 (a metal-containing azo dye), E-82 (an oxynaphthoic acid-based metal complex), E-84 (a salicylic acid-based metal complex), and E-89 (a phenolic condensate) (all manufactured by Orient Chemical Industry Co., Ltd.), TP-302 and TP-415 (quaternary ammonium salt molybdenum complexes) (both manufactured by Hodogaya Chemical Co., Ltd.), Copy Charge PSY VP2038 (a quaternary ammonium salt), Copy Blue PR (a triphenylmethane derivative), Copy Charge NEG VP2036 (a quaternary ammonium salt), and Copy Charge NX Examples include VP434 (manufactured by Hoechst), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. The charge control agent should be used in an amount that exhibits performance without inhibiting fixation, and is preferably contained in the matrix particles at a concentration of 0.5% to 5% by mass, preferably 0.8% to 3% by mass.

[0139] <<Cleaning performance enhancer>> The cleaning agent is not particularly limited as long as it is added to the particles to remove residual developer after transfer from the electrostatic latent image carrier or primary transfer medium, and can be appropriately selected according to the purpose. Examples of cleaning agents include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles are preferably those with a relatively narrow particle size distribution, and those with a volume-average particle size of 0.01 μm to 1 μm are preferred.

[0140] <<Magnetic materials>> There are no particular restrictions on the magnetic material; it can be appropriately selected from known materials depending on the purpose, such as iron powder, magnetite, and ferrite. Among these, white materials are preferred in terms of color.

[0141] (Particle properties) <Particle size> The particle size of the particles of the present invention may be measured using a Coulter Multisizer III (manufactured by Coulter), and the particle size can be determined, for example, by the following procedure. First, 2 mL of surfactant (sodium dodecylbenzenesulfonate, manufactured by Tokyo Chemical Industry Co., Ltd.) is added as a dispersant to 100 mL of electrolyte. The electrolyte is prepared as an approximately 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. To the mixture of electrolyte and surfactant, 10 mg of the sample of particles to be measured is added in solid form to obtain an electrolyte in which the sample is suspended. The electrolyte in which the sample is suspended is dispersed using an ultrasonic disperser for approximately 1 to 3 minutes, and the volume and number of particles are measured using a Coulter Multisizer III with a 100 μm aperture, and the volume distribution and number distribution are calculated. From the obtained distribution, the volume-average particle size (Dv) of the particles is determined.

[0142] <Method for measuring melting point and glass transition temperature (Tg)> The melting point and glass transition temperature (Tg) of the particles of the present invention can be measured, for example, using a DSC system (differential scanning calorimeter) ("Q-200", manufactured by TA Instruments). Specifically, the melting point and glass transition temperature of the target sample can be measured, for example, by the following procedure. First, approximately 5.0 mg of the target particle sample is placed in an aluminum sample container, the sample container is placed on a holder unit, and the container is set in an electric furnace. Next, under a nitrogen atmosphere, the sample is heated from -80°C to 150°C at a heating rate of 10°C / min (first heating). After that, the sample is cooled from 150°C to -80°C at a cooling rate of 10°C / min, and then heated again to 150°C at a heating rate of 10°C / min (second heating). In each of these first and second heating cycles, the DSC curve can be measured, for example, using a differential scanning calorimeter ("Q-200", manufactured by TA Instruments). From the obtained DSC curves, the analysis program in the Q-200 system can be used to select the DSC curve for the first heating cycle and determine the glass transition temperature (Tg) of the target sample during the first heating cycle. Similarly, the DSC curve for the second heating cycle can be selected to determine the glass transition temperature (Tg) of the target sample during the second heating cycle.

[0143] Furthermore, using the analysis program in the Q-200 system, the DSC curve obtained can be selected from the obtained DSC curves to determine the melting point at the first heating cycle by selecting the DSC curve for the first heating cycle. Similarly, the DSC curve for the second heating cycle can be selected to determine the melting point at the second heating cycle by selecting the DSC curve for the second heating cycle.

[0144] Furthermore, in this specification, the glass transition temperature (Tg) and melting point of amorphous polyester resin A, amorphous polyester resin B, crystalline polyester resin C, and other components such as mold release agents may also be determined by the same method as described above. Unless otherwise specified, the endothermic peak top temperature and glass transition temperature (Tg) at the second heating stage shall be used as the melting point and glass transition temperature (Tg) of each sample.

[0145] <Average particle diameter, average circularity> For measuring the average particle diameter and average circularity of the particles of the present invention, for example, a flow-type particle image analyzer (FPIA-3000, manufactured by Sysmex Corporation) can be used. As a specific measurement method, for example, 0.1 ml to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, as a dispersant is added to 100 ml to 150 ml of water from which impurities have been removed in a container, and then about 0.1 g to 0.5 g of the particle sample to be measured is added. The suspension in which the sample is dispersed is subjected to dispersion treatment in an ultrasonic disperser for about 1 to 3 minutes, and the average particle diameter and average circularity are measured using a flow-type particle image analyzer with a dispersion concentration of 3,000 particles / μl to 10,000 particles / μl. However, the particle diameter is defined as the equivalent diameter of a circle, and the average particle diameter is determined by the equivalent diameter of a circle (based on the number of particles). The analysis conditions for the flow-type particle image analyzer are as follows. • Particle size limitation: 0.5 μm ≤ Equivalent circle diameter (based on number of particles) ≤ 200.0 μm • Particle shape limitation: 0.93 < Circularity ≤ 1.00 The mean circularity is defined as follows: (Average circularity) = (Perimeter of a circle equal to the projected area) / (Perimeter of the projected image)

[0146] <Measuring molecular weight> The molecular weight of each component of the particles of the present invention may be determined, for example, by measuring a sample that has undergone the following pretreatment using the following measuring apparatus and column, under the following measurement conditions.

[0147] - Measuring device - Gel permeation chromatography (GPC) measurement device: GPC-8220GPC (Manufactured by Tosoh Corporation) -column- Column: TSKgel SuperHZM-H 15cm 3-row (manufactured by Tosoh Corporation) -Sample and pretreatment- • Sample: 100 μL of sample with 0.15% by mass of particles. • Pretreatment: The particles to be measured are dissolved in tetrahydrofuran THF (containing stabilizer, manufactured by Wako Pure Chemical Industries) at a concentration of 0.15% by mass, then filtered through a 0.2 μm filter, and the filtrate is used as the sample. -Measurement conditions- ·Temperature: 40℃ • Solvent: THF ·Flow rate: 0.35mL / min

[0148] For measuring the molecular weight of the above sample, the molecular weight distribution of the sample may be calculated from the relationship between the logarithm of a calibration curve prepared using several monodisperse polystyrene standard samples and the count. Showa Denko's Showdex STANDARD Std. Nos. S-7300, S-210, S-390, S-875, S-1980, S-10.9, S-629, S-3.0, and S-0.580 may be used as standard polystyrene samples for calibration curve preparation. An RI (refractive index) detector may be used.

[0149] (Particle manufacturing method) The present invention describes a method for producing particles. The method for producing particles of the present invention includes an oil phase preparation step, an aqueous phase preparation step, a phase inversion emulsification step, a solvent removal step, an aggregation step, and a fusion step, and further includes, if necessary, other steps such as a shelling step, a washing and drying step, an annealing step, a classification step, and an external additive step.

[0150] <Oil phase preparation process> In the oil phase preparation process, first, at least one of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), which are the raw materials for the particles, along with other resins, and optionally, colorants, prepolymers, release agents, and other materials are dissolved or dispersed in an organic solvent to prepare the oil phase. Some of these materials may be added in the aggregation process described later.

[0151] There are no particular restrictions on the method for preparing the oil phase, and it can be appropriately selected depending on the purpose. For example, one method involves gradually adding raw materials such as resin to an organic solvent while stirring, and dissolving or dispersing them.

[0152] For dispersion, known methods can be used, such as dispersers like bead mills and disc mills.

[0153] The raw materials used in the oil phase preparation process may be those described in the sections on <matrix particles> and <other components> above. These may be used individually or in combination of two or more.

[0154] There are no particular restrictions on the organic solvent, and it can be appropriately selected depending on the purpose. However, a volatile solvent with a boiling point of less than 100°C is preferred because it facilitates the subsequent removal of the organic solvent.

[0155] Examples of such organic solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, and isopropyl alcohol. These may be used individually or in combination of two or more.

[0156] When the resin to be dissolved or dispersed in an organic solvent is a resin having a polyester skeleton, ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate, or ketone-based solvents such as methyl ethyl ketone and methyl isobutyl ketone are preferred as organic solvents due to their high solubility. Among these, methyl acetate, ethyl acetate, or methyl ethyl ketone are preferred as organic solvents due to their high solvent removal properties.

[0157] There are no particular restrictions on the amount of organic solvent used, and it can be appropriately selected depending on the purpose, but 40 to 300 parts by mass is preferred, 60 to 140 parts by mass is more preferred, and 80 to 120 parts by mass is even more preferred, per 100 parts by mass of the raw material of the parent particles.

[0158] <Aqueous phase preparation process> In the aqueous phase preparation process, an aqueous medium that will become the aqueous phase is prepared.

[0159] There are no particular restrictions on the aqueous medium, and it can be appropriately selected from known ones, such as water, a solvent miscible with water, or a mixture thereof. From the viewpoint of granulation, the concentration of the solvent miscible with water is preferably less than or equal to the saturation concentration with respect to the ion-exchanged water used in the phase inversion emulsification process.

[0160] There are no particular restrictions on the solvent that can be miscible with water, and any known solvent can be appropriately selected, such as alcohols, dimethylformamide, tetrahydrofuran, cellulose, lower ketones, or esters.

[0161] Examples of alcohols include methanol, isopropanol, or ethylene glycol.

[0162] Examples of lower ketones include acetone or methyl ethyl ketone.

[0163] Examples of esters include ethyl acetate.

[0164] These can be used individually or in combination of two or more.

[0165] <Phase inversion emulsification process> In the phase inversion emulsification process, the oil phase obtained in the oil phase preparation process is converted into oil droplets.

[0166] After neutralizing the oil phase, the aqueous phase is added to the neutralized oil phase, and a dispersion of oil droplets is obtained by phase inversion emulsification, which converts the water-in-oil dispersion to an oil-in-water dispersion.

[0167] For neutralizing the oil phase, it is preferable to use a base, and as the base for neutralizing the oil phase, either a basic inorganic compound or a basic organic compound may be used. Examples of basic inorganic compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and ammonia. Examples of basic organic compounds include N,N-dimethylethanolamine, N,N-diethylethanolamine, triethanolamine, trippropanolamine, tributanolamine, triethylamine, n-propylamine, n-butylamine, isopropylamine, monomethanolamine, morpholine, methoxypropylamine, pyridine, vinylpyridine, and isophoronediamine.

[0168] Phase inversion emulsification is performed by stirring. Stirring is carried out using a conventional stirrer or dispersion device to ensure uniform mixing and dispersion. A conventional stirrer and dispersion device may be used in combination.

[0169] There are no particular restrictions on the type of stirring blade used in a stirrer; they can be appropriately selected according to the viscosity of the solution. Examples include low-viscosity stirring blades such as paddles and propellers, medium-viscosity stirring blades such as anchors and Maxblende, and high-viscosity stirring blades such as helical ribbons.

[0170] Among these, it is preferable to use a low-viscosity or medium-viscosity stirring blade, and more preferable to use a paddle or anchor, as this allows the volume-average particle size of the oil droplets to be controlled within a desirable range.

[0171] When using a stirring blade, there are no particular restrictions on conditions such as rotation speed, stirring time, and stirring temperature. There is no single option; you can choose the appropriate option depending on your purpose.

[0172] When using a stirring blade, there are no particular restrictions on the rotational speed, but 100 rpm to 1,000 rpm is preferred, and 200 rpm to 600 rpm is more preferred.

[0173] The stirring time and stirring temperature are not particularly limited and may be selected arbitrarily as appropriate depending on the purpose.

[0174] There are no particular restrictions on the dispersion device, and examples include ultrasonic dispersers, bead mills, ball mills, roll mills, homomixers, ultramixers, disperser mixers, through-type high-pressure dispersion devices, impact-type high-pressure dispersion devices, porous high-pressure dispersion devices, ultra-high-pressure homogenizers, ultrasonic homogenizers, etc.

[0175] Furthermore, a dispersant may be used as needed. There are no particular restrictions on the dispersant, and it can be appropriately selected depending on the purpose. Examples include surfactants, dispersants of poorly water-soluble inorganic compounds, and polymeric protective colloids. These may be used individually or in combination of two or more. Among these, surfactants are preferred.

[0176] There are no particular restrictions on the surfactant used; it can be appropriately selected depending on the purpose. For example, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc., can be used.

[0177] There are no particular restrictions on the anionic surfactant, and it can be appropriately selected depending on the purpose. Examples include alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters. Among these, those having a fluoroalkyl group are preferred.

[0178] <Desolvent removal process> In the desolvation step, the organic solvent is removed from the resulting oil droplet dispersion.

[0179] To remove the organic solvent from the resulting oil droplet dispersion, a method can be employed in which the entire system is gradually heated while stirring, and the organic solvent in the oil droplets is completely evaporated and removed.

[0180] Alternatively, the organic solvent in the oil droplets can be completely removed by spraying the resulting oil droplet dispersion into a dry atmosphere while stirring. Furthermore, the organic solvent may be evaporated by reducing the pressure while stirring the oil droplet dispersion. Alternatively, the organic solvent may be evaporated by blowing a gas onto the oil droplet dispersion while stirring.

[0181] These methods may be used individually or in combination.

[0182] The drying atmosphere in which the oil droplet dispersion is sprayed generally consists of heated gases such as air, nitrogen, carbon dioxide, and combustion gases, particularly various gas streams heated to a temperature above the boiling point of the maximum boiling point solvent used. The desired quality can be obtained with short processing times using spray dryers, belt dryers, rotary kilns, etc.

[0183] By removing the organic solvent from the resulting oil droplet dispersion using the above method, a dispersion of raw material fine particles can be obtained.

[0184] <Agglomeration process> In the agglomeration process, the obtained raw material fine particle dispersion is agglomerated while being stirred until it reaches a desired particle size to obtain agglomerated particles.

[0185] Existing methods such as adding a flocculant and adjusting the pH can be used to induce flocculation. When adding a flocculant, it can be added directly, but it is preferable to use an aqueous solution of the flocculant to avoid localized high concentrations. Furthermore, it is preferable to add the flocculant gradually while observing the particle size of the raw material particles.

[0186] The temperature of the raw material particle dispersion during aggregation is preferably between [the glass transition temperature (Tg) of the resin used] and [the glass transition temperature (Tg) of the resin used + 10°C]. If the liquid temperature of the raw material particle dispersion is above [the glass transition temperature (Tg) of the resin used], aggregation proceeds appropriately and efficiently. If it is below [the glass transition temperature (Tg) of the resin used + 10°C], the aggregation rate does not become too fast, coarse particles are less likely to be generated, and it is easier to achieve uniform particle size.

[0187] Once the target particle size is reached, aggregation is stopped. Methods for stopping aggregation include, for example, adding a salt or chelating agent with a low ionic charge, adjusting the pH, lowering the temperature of the dispersion, or diluting the concentration by adding a large amount of aqueous medium.

[0188] In the aggregation process, colorants, crystalline resins, and release agents may be added. In this case, by mixing the oil phase material with an oil droplet dispersion or raw material fine particle dispersion and then agglomerating it, aggregated particles in which the colorant, crystalline resin, and release agent are uniformly dispersed can be obtained.

[0189] -Agglutinant- As a coagulant, a general-purpose coagulant can be used. The coagulant may be used alone or in combination of two or more types.

[0190] Since metal ions function as crosslinking agents that crosslink the edges of resins, metal salts of monovalent metals such as sodium and potassium, metal salts of divalent metals such as calcium and magnesium, and metal salts of trivalent metals such as iron and aluminum can be used as flocculants.

[0191] Generally, it is preferable to use a metal salt of a divalent metal from the viewpoint of making it easier to achieve uniform particle size of aggregated particles. When a metal salt of a divalent metal is used as a flocculant, the crosslinking effect is not reduced, and even when there are large differences in the structure of the resins contained, such as when biomass resin, amorphous resin with many aromatic ring skeletons, and PET or PBT are used, the crosslinking reaction rate does not become too fast, making it easy to maintain good uniformity of particle size of the aggregated particles. Among the metal salts of divalent metals, the metal salt of Mg in particular exhibits good flocculation properties.

[0192] In this embodiment, it is preferable to use a metal salt of sodium with a low ionic charge as a flocculant. By using a metal salt of sodium as a flocculant, flocculation can be stopped efficiently.

[0193] The amount of metal used in flocculants, etc., in the parent particles is preferably 0.05% to 1% by mass, as too much remaining metal in the particles can worsen their electrostatic properties. If the amount of metal in the parent particles is 0.05% by mass or more, the amount of metal used for flocculation is sufficient, the flocculation force is sufficient, and it is easy to make the particle size uniform. If it is 1% by mass or less, it does not worsen the electrostatic properties of the particles. The type and amount of metal in the particles can be adjusted by the type and amount of flocculant and stopper, and the washing conditions in the washing process.

[0194] <Fusing process> In the fusion process, the aggregated particles obtained in the aggregation process are fused together by heat treatment to reduce irregularities and make them spherical, thereby obtaining a dispersion of the fused aggregated particles. Fusion can be performed by heating the dispersion of aggregated particles while stirring. The temperature of the liquid is preferably between [glass transition temperature (Tg) of the resin used + 5°C] and [glass transition temperature (Tg) of the resin used + 30°C].

[0195] <Shelling process> Furthermore, the particle manufacturing method of the present invention may optionally include a shelling step. In the shelling step, a shell layer is formed on the spherical particles obtained in the fusion step.

[0196] There are no particular restrictions on the method for forming the shell layer, and it can be appropriately selected depending on the purpose. For example, one method involves producing aggregated particles in an aggregation step, then adding and stirring a dispersion of resin fine particles that will form the shell layer, adding an aqueous magnesium sulfate solution, and then performing a fusion step. Another method for forming the shell layer is to produce spherical particles of the desired particle size in a fusion step, then add an amorphous resin, and repeat the aggregation and fusion steps to form the shell layer.

[0197] -Resin fine particles- The resin fine particles may include a resin obtained by condensing acid monomer units and alcohol monomer units, and preferably include at least one of polyethylene terephthalate and polybutylene terephthalate. There are no particular restrictions on the molecular weight distribution, composition, manufacturing method, or form of polyethylene terephthalate or polybutylene terephthalate used, and they can be appropriately selected according to the purpose. However, from the viewpoint of reducing the environmental impact, it is preferable to use recycled materials, off-spec fiber waste, or pellets, and it is even more preferable to use recycled materials processed into flakes.

[0198] The acid monomers and units mentioned above are preferably monomers having a carboxyl group, such as adipic acid, terephthalic acid, succinic acid, and rosinic acid.

[0199] The alcohol monomer units are preferably monomers having a hydroxyl group, such as Bis-A-EO2mol adduct, Bis-A-PO2mol adduct, 1,2-propanediol, trimethylolpropane, glycerin, neopentyl glycol, and the like.

[0200] <Washing and drying process> In the washing and drying process, only the portion that will become the parent particles is taken from the dispersion of the aggregated particle fused material obtained by the above method, washed, and dried.

[0201] The dispersion of the aggregated particle fused material obtained by the above method contains auxiliary materials such as flocculants in addition to the parent particle portion. Therefore, washing is performed to separate only the parent particle portion from the dispersion. Washing methods include, but are not limited to, centrifugal separation, vacuum filtration, and filter pressing. A cake of the particle portion can be obtained by any of these methods. If washing is not sufficient in a single operation, the obtained cake may be dispersed again in an aqueous solvent to form a slurry, and the process of separating the parent particle portion using the above-mentioned centrifugal separation, vacuum filtration, or filter pressing method may be repeated. Alternatively, if washing is performed by vacuum filtration or filter pressing, a method may be adopted in which the aqueous solvent is passed through the cake to wash away the auxiliary materials that the parent particle portion has incorporated. The aqueous solvent used for this washing can be water, or a mixed solvent of water with an alcohol such as methanol or ethanol. However, water is preferred in terms of cost and environmental impact due to wastewater treatment.

[0202] The washed portion that will become the parent particles contains a large amount of aqueous solvent, so by drying it to remove the aqueous solvent, only the portion that will become the parent particles can be obtained.

[0203] For drying, various types of dryers can be used, such as spray dryers, vacuum freeze dryers, reduced pressure dryers, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, and agitated dryers. It is preferable to dry the resulting particles until the final moisture content is less than 1%. Furthermore, since the resulting particles after drying are soft aggregates, if this causes problems during use, the aggregates may be broken up and the soft aggregates loosened using equipment such as jet mills, Henschel mixers, super mixers, coffee mills, Auster blenders, and food processors.

[0204] <Annealing Process> Furthermore, the particle manufacturing method of the present invention may include an annealing step as needed. Specifically, as an annealing method in the annealing step, when the raw materials of the parent particles include amorphous resin and crystalline resin, a method of storing the material for 10 hours or more at a temperature within the range of [glass transition temperature (Tg)] ± 5°C of the resin portion that will become the parent particles] after the washing and drying step described above may be used. By performing the annealing step, the amorphous resin and crystalline resin undergo phase separation, improving the particle fixation.

[0205] <Classification process> The aggregates dried in the washing and drying process can be classified using known techniques such as a sieve with a predetermined mesh size or an elbow jet classifier to obtain matrix particles of a desired particle size.

[0206] <External addition process> The resulting matrix particles are mixed with an external additive. At least one of the added external additives is coated with a metal hydroxide, and other external additives may also be added and mixed.

[0207] Specific mixing methods include applying impact force to the mixture using high-speed rotating blades, and introducing the mixture into a high-speed airflow to accelerate it and causing the particles, or composite particles, to collide with a suitable impact plate.

[0208] Examples of mixing devices include Ongmill (manufactured by Hosokawa Micron Corporation), modified I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) with reduced grinding air pressure, hybridization systems (manufactured by Nara Machine Works Co., Ltd.), cryptron systems (manufactured by Kawasaki Heavy Industries, Ltd.), and automatic mortars.

[0209] Because the particles of the present invention have the above-described properties, they can be effectively used as materials for image formation, such as toner, developer, toner set, toner storage unit, and image forming apparatus.

[0210] (toner) The toner of the present invention contains the particles of the present invention. The toner of the present invention has a low environmental impact, excellent charge stability over time, and can provide a toner that exhibits excellent charge stability even in high humidity environments. Furthermore, even when using biomass-derived resin, the toner of the present invention can provide images with excellent image quality and excellent low-temperature fixation.

[0211] (Developer) The developer of the present invention contains the toner of the present invention and may optionally contain other components such as a carrier, as appropriate. The developer of the present invention has excellent transferability, electrostatic properties, etc., and can stably form high-quality images.

[0212] The developer of the present invention may be a one-component developer or a two-component developer, but when used in high-speed printers and the like to cope with the recent increase in information processing speed, a two-component developer is preferable from the viewpoint of improving lifespan.

[0213] When the toner of the present invention is used in a one-component developer, even when toner is balanced, fluctuations in toner particle size are small, toner filming onto the developing roller and toner fusion onto components such as blades that thin the toner layer are minimized, and high-quality images can be obtained in the developing device.

[0214] When the toner of the present invention is used in a two-component developer, it can be mixed with a carrier and used as a developer. When the toner of the present invention is used in a two-component developer, even if the toner is balanced over a long period of time, the toner particle size does not fluctuate much, and good and stable developability and images can be obtained even with long-term agitation in the developing apparatus.

[0215] The carrier content in the two-component developer can be appropriately selected depending on the purpose, but 90 to 98 parts by mass and more preferably 93 to 97 parts by mass per 100 parts by mass of the two-component developer is preferred.

[0216] The developer of the present invention can be suitably used for image formation by various known electrophotographic methods, such as magnetic one-component development methods, non-magnetic one-component development methods, and two-component development methods.

[0217] <Career> The carrier is not particularly limited and can be appropriately selected according to the purpose, but it is preferable that it has a core material and a coating layer covering the core material, and it is more preferable that the coating layer is a resin layer.

[0218] <<Core material>> There are no particular restrictions on the core material, and it can be appropriately selected according to the purpose. Examples include manganese-strontium materials with a magnetization of 50 emu / g to 90 emu / g, and manganese-magnesium materials with a magnetization of 50 emu / g to 90 emu / g. In order to ensure image density, it is preferable to use highly magnetized materials such as iron powder of 100 emu / g or more, or magnetite with a magnetization of 75 emu / g to 120 emu / g. Furthermore, it is preferable to use low magnetized materials such as copper-zinc materials with a magnetization of 30 emu / g to 80 emu / g, as this can mitigate the impact of the developer in a condensed state on the electrostatic latent image carrier and is advantageous for improving image quality. These may be used individually or in combination of two or more types.

[0219] The volume-average particle size of the core material is not particularly limited and can be appropriately selected depending on the purpose, but 10 μm to 150 μm is preferred, and 40 μm to 100 μm is more preferred. If the volume-average particle size of the core material is 10 μm or more, the problem of a large amount of fine powder in the carrier, a decrease in magnetization per particle, and carrier scattering can be effectively prevented. On the other hand, if the volume-average particle size of the core material is 150 μm or less, the specific surface area decreases, which can cause toner scattering, and in full-color printing with many solid areas, the reproduction of solid areas can be particularly poor, which can be effectively prevented.

[0220] <<Resin layer>> The resin layer may contain a resin and, if necessary, other components. As the resin used in the resin layer, any known material capable of imparting the required electrostatic properties can be used. Specifically, silicone resin, acrylic resin, or a combination thereof is preferred. Furthermore, the composition for forming the resin layer preferably contains a silane coupling agent.

[0221] The average thickness of the resin layer is preferably 0.05 μm to 0.50 μm.

[0222] (Developer container) The developer of the present invention is contained in a developer container. The developer container is not particularly limited and can be appropriately selected from known containers, but examples include those having a container body and a cap.

[0223] Furthermore, the size, shape, structure, and material of the container body are not particularly limited, but the shape is preferably cylindrical, with spiral-shaped irregularities formed on the inner surface, allowing the developer contents to move towards the discharge port by rotation, and it is particularly preferable that some or all of the spiral-shaped irregularities have a bellows function. In addition, the material is not particularly limited, but it is preferable that it has good dimensional accuracy, and examples of resin materials include polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, and polyacetal resin.

[0224] The developer container is easy to store and transport, and offers excellent handling, so it can be detachably attached to the image forming apparatus, process cartridge, etc., described later, and used for replenishing the developer.

[0225] (Toner storage unit) The toner storage unit can store the toner of the present invention. A toner storage unit refers to a unit having the function of storing toner, in which toner is stored. Here, examples of the toner storage unit include a toner storage container, a developer, and a process cartridge.

[0226] A toner container refers to a container that holds toner.

[0227] A developing unit refers to a device that contains toner and has a developing mechanism.

[0228] A process cartridge is defined as a device that integrates at least an electrostatic latent image carrier and a developing means, contains toner, and is detachable from an image forming apparatus. The process cartridge may further include at least one selected from a charging means, an exposure means, a cleaning means, etc.

[0229] By mounting the toner storage unit containing the toner of the present invention into an image forming apparatus and performing image formation, it is possible to form images with toner that has a low environmental impact, excellent charge stability over time, and excellent charge stability even in high humidity environments, thus enabling the production of high-quality images.

[0230] (Image forming apparatus) The image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, and a developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner of the present invention to form a toner image, and may further include other configurations as necessary.

[0231] In addition to the electrostatic latent image carrier, electrostatic latent image forming means, and developing means described above, the image forming apparatus of the present invention preferably includes a transfer means for transferring the toner image to an image forming medium and a fixing means for fixing the transferred image onto the surface of the image forming medium. Other means may include static elimination means, cleaning means, recycling means, control means, etc.

[0232] In the developing means, a toner image may be formed by using a developer that contains the toner of the present invention and, if necessary, also contains other components such as a carrier.

[0233] <Electrostatic latent image carrier> The material, shape, structure, size, etc. of the electrostatic latent image carrier are not particularly limited and can be appropriately selected from known materials. Examples of materials for the electrostatic latent image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine.

[0234] There are no particular restrictions on the shape of the electrostatic latent image carrier, and it can be appropriately selected depending on the purpose, but a cylindrical shape is preferred. There are no particular restrictions on the outer diameter of the cylindrical electrostatic latent image carrier, and it can be appropriately selected depending on the purpose, but 3 mm to 100 mm is preferred, 5 mm to 50 mm is more preferred, and 10 mm to 30 mm is particularly preferred.

[0235] <Electrostatic latent image forming means> The electrostatic latent image forming unit is not particularly limited as long as it is a means for forming an electrostatic latent image on an electrostatic latent image carrier, and can be appropriately selected according to the purpose. The electrostatic latent image forming means may include, for example, a charger, which is a charging member that uniformly charges the surface of the electrostatic latent image carrier, and an exposure member, which is an exposure member that exposes the surface of the electrostatic latent image carrier in an image-like manner.

[0236] The charger is not particularly limited and can be appropriately selected according to the purpose, but examples include contact chargers equipped with conductive or semiconductive rolls, brushes, films, rubber blades, etc., and non-contact chargers that utilize corona discharge such as Corotron and Scorotron.

[0237] The shape of the charger can be anything other than a roller, such as a magnetic brush or a fur brush, and can be selected according to the specifications and configuration of the image forming apparatus.

[0238] Preferably, the charger is positioned in contact with or without contact with the electrostatic latent image carrier, and charges the surface of the electrostatic latent image carrier by superimposing DC and AC voltages. Alternatively, it is preferable that the charger is a charging roller positioned in close proximity to the electrostatic latent image carrier via a gap tape, and charges the surface of the electrostatic latent image carrier by superimposing DC and AC voltages on the charging roller.

[0239] While the charger is not limited to a contact-type charger, it is preferable to use a contact-type charging element because it allows for the creation of an image forming apparatus with reduced ozone generation from the charger.

[0240] The exposure device is not particularly limited as long as it can expose the surface of an electrostatic latent image carrier charged by a charger in the manner of the image to be formed, and can be appropriately selected according to the purpose. Examples of exposure devices include copying optical systems, rod lens array systems, laser optical systems, and liquid crystal shutter optical systems.

[0241] There are no particular restrictions on the light source used in an exposure unit, and it can be appropriately selected according to the purpose. Examples include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescent devices (ELs), and other types of light-emitting materials.

[0242] Furthermore, various filters such as sharp-cut filters, band-pass filters, near-infrared cut filters, dichroic filters, interference filters, and color temperature conversion filters can be used to illuminate only the desired wavelength range.

[0243] Furthermore, the exposure unit may employ a back-facing method that exposes the electrostatic latent image carrier in an image-like manner from the back side.

[0244] <Developing method> The developing means is not particularly limited as long as it can develop the electrostatic latent image formed on the electrostatic latent image carrier to form a toner image, and can be appropriately selected according to the purpose. The developing means can preferably be one that includes a developer that contains toner and can apply toner to the electrostatic latent image by contact or non-contact, and a developer equipped with a toner container is preferred.

[0245] The developing unit may be a single-color developing unit or a multi-color developing unit. Suitable developing devices include, for example, a developing apparatus that has an agitator that frictionally agitates and charges the toner, a magnetic field generating unit fixed inside, and a developer carrier such as a magnetic roller that carries the developer containing the toner on its surface and is rotatable.

[0246] <Transfer method> The transfer means is preferably configured to include a primary transfer means for transferring a toner image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto an image-forming medium. The intermediate transfer body is not particularly limited and can be appropriately selected from known transfer bodies depending on the purpose; for example, a transfer belt is a suitable example.

[0247] The transfer means (first transfer means and second transfer means) preferably includes at least a transfer device that exfoliates and charges the toner image formed on the electrostatic latent image carrier toward the image-forming medium. There may be one transfer means or two or more.

[0248] Examples of transfer devices include corona discharge transfer devices, transfer belts, transfer rollers, pressure transfer rollers, and adhesive transfer devices.

[0249] While plain paper is typically used as the image-forming medium, there are no particular restrictions as long as it is capable of transferring the unfixed image after development. It can be appropriately selected from known image-forming media such as recording paper depending on the purpose, and PET bases for OHPs can also be used.

[0250] <Means of fixing> The fixing means is not particularly limited and can be appropriately selected according to the purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing unit include a combination of a heating roller and a pressing roller, and a combination of a heating roller, a pressing roller, and an endless belt.

[0251] The fixing means preferably has a heating body including a heating element, a film contacting the heating body, and a pressing member pressing against the heating body through the film, and is a heating and pressing unit capable of heat-fixing by passing a medium to be image-formed on which an unfixed image is formed between the film and the pressing member.

[0252] For heating in the heating and pressing unit, usually, 80°C to 200°C is preferable.

[0253] The surface pressure in the heating and pressing unit is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 10 N / cm 2 ~80 N / cm 2 Preferably.

[0254] In this embodiment, depending on the purpose, a known optical fixing device may be used together with or instead of the fixing unit.

[0255] <Other means> As other means, the image forming apparatus of the present invention can include, for example, charge removing means, cleaning means, recycling means, control means, and the like.

[0256] <<Charge removing means>> The charge removing means is not particularly limited as long as a charge removing bias can be applied to the electrostatic latent image carrier, and can be appropriately selected from known charge removers. For example, a charge removing lamp is preferably used.

[0257] <<Cleaning means>> The cleaning means only needs to be able to remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Examples of the cleaning means include a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, a web cleaner, etc.

[0258] By having the cleaning means, the image forming apparatus of the present invention can improve the cleaning performance. That is, by controlling the adhesion force between toners, the fluidity of the toner is controlled, and the cleaning performance can be improved. Also, by controlling the characteristics of the toner after deterioration, excellent cleaning quality can be maintained even under severe conditions such as high durability and high temperature and high humidity. Furthermore, since the external additives can be sufficiently released from the toner on the electrostatic latent image carrier, a high cleaning performance can be achieved by forming a deposition layer (dam layer) of the external additives in the cleaning blade nip portion.

[0259] <<Recycling means>> The recycling means is not particularly limited, and known conveying means and the like can be mentioned.

[0260] <<Control means>> The control means can control the movements of the above-mentioned respective parts. The control means is not particularly limited as long as it can control the movements of the above-mentioned respective means, and can be appropriately selected according to the purpose. For example, control devices such as a sequencer and a computer can be mentioned.

[0261] In the image forming apparatus of the present invention, since image formation can be performed using the toner of the present invention, an image with high quality can be obtained because it has a low environmental load, excellent charging stability over time, and excellent charging stability even in a high humidity environment.

[0262] (Image forming method) The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, and a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner of the present invention to form a toner image.

[0263] Furthermore, the image forming method of the present invention preferably includes, in addition to the electrostatic latent image formation step and the development step described above, a transfer step of transferring the toner image to an image forming medium and a fixing step of fixing the transferred image on the surface of the image forming medium. In addition to these, other processes such as static elimination, cleaning, recycling, and control processes may be included as needed.

[0264] The image forming method can be suitably carried out by the image forming apparatus, the electrostatic latent image forming step can be suitably carried out by the electrostatic latent image forming means, the developing step can be suitably carried out by the developing means, the transfer step can be suitably carried out by the transfer means, the fixing step can be suitably carried out by the fixing means, and the other steps can be suitably carried out by the other means.

[0265] <Electrostatic latent image formation process> The electrostatic latent image formation process is a process of forming an electrostatic latent image on an electrostatic latent image carrier, and may include a charging step of charging the surface of the electrostatic latent image carrier and an exposure step of exposing the charged surface of the electrostatic latent image carrier to form an electrostatic latent image. Charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger. Exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier in an image-like manner using the exposure device. Formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it in an image-like manner, and can be performed by an electrostatic latent image formation means.

[0266] <Developing process> The development process is a process of sequentially developing an electrostatic latent image with multiple toners to form a toner image. The toner image can be formed, for example, by developing the electrostatic latent image using the toner of the present invention, and this can be done using a developing unit.

[0267] In the development process, the toner of the present invention may be used, and a developer containing the toner of the present invention, and optionally containing other components such as a carrier, may be used to form a toner image.

[0268] Inside the developing unit, for example, toner and carrier are mixed and stirred, and the friction during this process causes the toner to become charged. This charge is then held in a pile-like state on the surface of the rotating magnetic roller, forming a magnetic brush. Since the magnetic roller is positioned near the electrostatic latent image carrier, some of the toner that makes up the magnetic brush formed on the surface of the magnetic roller is moved to the surface of the electrostatic latent image carrier by electrical attraction. As a result, the electrostatic latent image is developed by the toner, and a toner image is formed on the surface of the electrostatic latent image carrier.

[0269] <Transfer process> The transfer step is a step of transferring a toner image to an image-forming medium. Preferably, the transfer step involves using an intermediate transfer body to transfer the toner image onto the intermediate transfer body in a primary transfer, and then transferring the toner image onto the image-forming medium in a secondary transfer. More preferably, the transfer step includes using two or more toners, preferably full-color toners, a primary transfer step of transferring the toner image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer step of transferring the composite transfer image onto the image-forming medium. The transfer can be performed, for example, by charging an electrostatic latent image carrier with the toner image using a transfer charger, and can be suitably carried out by the transfer means described above.

[0270] <Fixing process> The fixing process is the process of fixing the toner image transferred to the image-forming medium using a fixing device. This process may be performed for each color developer after the toner is transferred to the image-forming medium, or it may be performed simultaneously for each color developer in a stacked state.

[0271] <Other processes> The image forming method of the present invention can further include other processes appropriately selected as needed, such as a charge removal process, a cleaning process, a recycling process, a control process, etc.

[0272] <<Charge removal process>> The charge removal process is a process of applying a charge removal bias to the electrostatic latent image carrier to perform charge removal, and can be preferably performed by a charge removal unit.

[0273] <<Cleaning process>> The cleaning process is a process of removing the toner remaining on the electrostatic latent image carrier, and can be preferably performed by the cleaning means.

[0274] <<Recycling process>> The recycling process is a process of recycling the toner removed by the cleaning process to the developing means, and can be preferably performed by the recycling means.

[0275] <<Control process>> The control process is a process of controlling the movement of each of the above means, and can be preferably performed by the control means.

[0276] In the image forming method of the present invention, since image formation can be performed using the toner of the present invention, it is possible to form an image with a toner that has a low environmental load, excellent charging stability over time, and excellent charging stability even in a high humidity environment, so that a high-quality image can be obtained.

[0277] Here, the image forming apparatus of the present invention will be described while referring to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the range that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc., and as long as the present invention exhibits its functions or effects in any embodiment, it is included in the scope of the present invention.

[0278] One embodiment of a method for forming an image using the image forming apparatus of the present invention will be described with reference to Figure 1. Although a printer is shown as an example of the image forming apparatus in this embodiment, the image forming apparatus of the present invention is not particularly limited as long as it is capable of forming an image using toner from a copier, facsimile, multifunction printer, etc.

[0279] Figure 1 shows an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 1 comprises a paper feeding unit 210, a transport unit 220, an image forming unit 230, a transfer unit 240, and a fuser unit 250. The paper feeding unit 210 includes a paper feed cassette 211 on which the paper to be fed P is stacked, and a paper feed roller 212 that feeds the paper P from the paper feed cassette 211 one sheet at a time.

[0280] The transport unit 220 includes a roller 221 that transports the paper P fed by the paper feed roller 212 toward the transfer unit 240, a pair of timing rollers 222 that hold the leading edge of the paper P transported by the roller 221 and wait, and send the paper to the transfer unit 240 at a predetermined timing, and a paper discharge roller 223 that discharges the paper P on which the color toner image has been fixed toward the paper discharge tray 224.

[0281] The image-forming unit 230 comprises, at predetermined intervals and in order from left to right in Figure 1, an image-forming unit 180Y that forms an image using a developer containing yellow toner, an image-forming unit 180C that uses a developer containing cyan toner, an image-forming unit 180M that uses a developer containing magenta toner, an image-forming unit 180K that uses a developer containing black toner, and an exposure unit 233.

[0282] The image forming unit 180 (180Y, 180C, 180M, 180K) is rotatable clockwise in Figure 1 and includes a photoreceptor drum 231 (231Y, 231C, 231M, 231K), which is an electrostatic latent image carrier on which an electrostatic latent image and a toner image are formed; a charger 232 (232Y, 232C, 232M, 232K) that uniformly charges the surface of the photoreceptor drum 231 (231Y, 231C, 231M, 231K); and a cleaner 236 (236Y, 236C, 236M, 236K) that removes toner remaining on the surface of the photoreceptor drum 231 (231Y, 231C, 231M, 231K).

[0283] The image forming unit 180 (180Y, 180C, 180M, 180K) is equipped with toner bottles 234 (234Y, 234C, 234M, 234K), which are developer containers that hold toner of each color, and sub-hoppers 160 (160Y, 160C, 160M, 160K) for replenishing the toner supplied from the toner bottles 234 (234Y, 234C, 234M, 234K).

[0284] In addition, when referring to any of the image forming units 180 (180Y, 180C, 180M, 180K), the term "image forming unit" is used.

[0285] The exposure unit 233 reflects the laser light L emitted from the light source 233a based on image information using polygon mirrors 233b (233bY, 233bC, 233bM, 233bK) which are rotated by a motor, and irradiates the photoreceptor drum 231 with the resulting light. Furthermore, the developer contains toner and carrier. The four image forming units 180 (180Y, 180C, 180M, 180K) are substantially identical in their mechanical configuration, differing only in the developer they use.

[0286] The transfer unit 240 includes a drive roller 241 and a driven roller 242, an intermediate transfer belt 243 that can rotate counterclockwise in Figure 1 in conjunction with the drive roller 241, primary transfer rollers 244 (244Y, 244C, 244M, 244K) positioned opposite the photoreceptor drum 231 (231Y, 231C, 231M, 231K) on either side of the intermediate transfer belt 243, and secondary opposing rollers 245 and 246 positioned opposite the intermediate transfer belt 243 at the transfer position of the toner image to the paper.

[0287] The fuser unit 250 has a heater inside and is equipped with a pressure roller 252 that rotatably applies pressure to the fuser belt 251, which heats the paper P, to form a nip. As a result, heat and pressure are applied to the color toner image on the paper P, and the color toner image is fixed.

[0288] The paper P on which the color toner image has been fixed is ejected to the paper output tray 224 by the paper output roller 223, completing the series of image formation processes. [Examples]

[0289] The embodiments will be described in more detail below with reference to examples and comparative examples, but the embodiments of the present invention are not limited to these examples and comparative examples.

[0290] <Synthesis of amorphous polyester resin A-1> In a reaction vessel equipped with a condenser, stirrer, and nitrogen inlet, 3-methyl-1,5-pentanediol, isophthalic acid, and plant-derived sebacic acid were added together with titanium tetraisopropoxide (1,000 ppm relative to the resin component) such that the molar ratio of hydroxyl groups to carboxyl groups (OH / COOH) was 1.1, the diol component consisted of 100 mol% 3-methyl-1,5-pentanediol, the dicarboxylic acid component consisted of 73 mol% isophthalic acid and 23 mol% sebacic acid, and the amount of trimethylolpropane in the total monomer was 1.5 mol%. The mixture was then heated to 200°C over approximately 4 hours, and then to 230°C over 2 hours, and the reaction was carried out until no more effluent was released. The mixture was then further reacted under reduced pressure of 10 mmHg to 15 mmHg for 5 hours to obtain [Intermediate Polyester A-1].

[0291] Next, the obtained [intermediate polyester A-1] and isophorone diisocyanate (IPDI) were added to a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube in a molar ratio (isocyanate groups of IPDI / hydroxyl groups of intermediate polyester) of 2.0. After diluting with ethyl acetate to a 50% ethyl acetate solution, the mixture was reacted at 150°C for 4 hours to obtain [prepolymer A-1].

[0292] The obtained [prepolymer A-1] was stirred in a reaction vessel equipped with a heater, stirrer, and nitrogen inlet tube. Then, [ketimine compound 1] was added dropwise to the reaction vessel in an amount that was equimolar to the amount of isocyanate in [prepolymer A-1]. After stirring at 45°C for 10 hours, the prepolymer extension was removed. The obtained prepolymer extension was dried under reduced pressure at 50°C until the amount of residual ethyl acetate was 100 ppm or less to obtain [amorphous polyester resin A-1]. The glass transition temperature (Tg) of the obtained [amorphous polyester resin A-1] was -51°C, and the weight-average molecular weight (Mw) was 17000.

[0293] <Synthesis of amorphous polyester resin B-1> Into a four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple, bisphenol A ethylene oxide 2-molar adduct, bisphenol A propylene oxide 2-molar adduct, terephthalic acid, and adipic acid were charged such that the molar ratio of bisphenol A propylene oxide 2-molar adduct to bisphenol A ethylene oxide 2-molar adduct (bisphenol A propylene oxide 2-molar adduct / bisphenol A ethylene oxide 2-molar adduct) was 60 / 40, the molar ratio of terephthalic acid to adipic acid (terephthalic acid / adipic acid) was 97 / 3, and the molar ratio of hydroxyl group to carboxyl group OH / COOH was 1.3. It was reacted at normal pressure and 230 °C for 8 hours together with titanium tetraisopropoxide (500 ppm based on the resin component), and further reacted for 4 hours under a reduced pressure of 10 mmHg to 15 mmHg. Then, trimellitic anhydride was added to the reaction vessel to be 1 mol% based on the total resin component, and reacted at 180 °C, normal pressure, and for 4 hours to obtain [amorphous polyester resin B-1]. The glass transition temperature (Tg) of the obtained [amorphous polyester resin B-1] was 65 °C, and the weight average molecular weight (Mw) was 9000.

[0294] <P-1: Introduction of PET (Polyethylene terephthalate)> Flaky recycled PET [P-1] was mixed so as to have the solid content ratio shown in Table 1 when mixing the materials for the above <Synthesis of amorphous polyester resin B-1>.

[0295] <Synthesis of crystalline polyester resin C-1> Sebacic acid and ethylene glycol were charged into a 5-L four-necked flask equipped with a nitrogen inlet tube, a water removal tube, a stirrer, and a thermocouple such that the molar ratio of hydroxyl group to carboxyl group OH / COOH was 0.9. It was reacted at 180 °C for 10 hours together with titanium tetraisopropoxide (500 ppm based on the resin component), then the temperature was raised to 200 °C and reacted for 3 hours, and further reacted at a pressure of 8.3 kPa for 2 hours to obtain [crystalline polyester resin C-1]. The melting point of the obtained [crystalline polyester resin C-1] was 72 °C, and the weight average molecular weight (Mw) was 20000.

[0296] <Manufacturing of crystalline polyester resin dispersion C-1> 45 parts by mass of [crystalline polyester resin C-1] and 450 parts by mass of ethyl acetate were placed in a container equipped with a stirring rod and thermometer. The mixture was heated to 80°C under stirring and maintained at 80°C for 5 hours, then cooled to 30°C in 1 hour. Dispersion was performed using a bead mill (Ultraviscomill, manufactured by AIMEX) under the following conditions: liquid transfer rate of 1 kg / hr, disk peripheral speed of 6 m / sec, and 80% by volume filling of 0.5 mm diameter zirconia beads, in 3 passes, to obtain [crystalline polyester resin dispersion C-1]. The volume-average particle size of the obtained crystalline polyester resin particles was 450 nm, and the solid content concentration of the crystalline polyester resin particles was 10% by mass.

[0297] <Manufacturing of polyester resin SR for shells> In a reaction vessel equipped with a condenser, a stirrer, and nitrogen inlet, 7.5 parts by mass of adipic acid, 63.5 parts by mass of terephthalic acid, and 4.8 parts by mass of succinic acid were added as acid monomers, and 35.5 parts by mass of Bis-A-EO 2mol adduct, 58.2 parts by mass of Bis-A-PO 2mol adduct, 23.4 parts by mass of 1,2-propanediol, and 1 part by mass of trimethylolpropane were added as alcohol monomers, such that the molar ratio of hydroxyl groups to carboxylic acid (OH / COOH) was 1.2. Furthermore, 1,000 ppm of tetrabutoxytitanate relative to the total amount of monomers was added as a condensation catalyst, and the temperature was raised to 200°C over 2 hours under a nitrogen stream, and then raised to 230°C over 8 hours, while the reaction was carried out for 5 hours, with the water produced being removed by distillation. Subsequently, the mixture was reacted under reduced pressure of 5 mmHg to 15 mmHg for 1 hour, cooled to 200°C, then 4.5 parts by mass of trimellitic anhydride were added, and the mixture was reacted at atmospheric pressure at 200°C for 1 hour. After that, the mixture was further reacted under reduced pressure of 5 mmHg to 20 mmHg until the desired molecular weight was reached, to obtain [polyester resin SR for shells]. When mixing the above acid monomer and alcohol monomer materials, flake-shaped recycled PET [P-1] was added so that 30% by mass of the solid content was flake-shaped recycled PET [P-1].

[0298] <Preparation of Polyester Resin Solution for Shell> Put 200 parts by mass of [Polyester Resin SR for Shell] and 200 parts by mass of methyl ethyl ketone into a container, and mix them with a TK homomixer (manufactured by Primix Corporation) at 5,000 rpm for 60 minutes to obtain [Polyester Resin Solution 1 for Shell]. The solid content concentration of the obtained [Polyester Resin Solution 1 for Shell] was 50% by mass.

[0299] <<Calculation Method for Solid Concentration of Polyester Resin Solution for Shell>> The solid content concentration of [Polyester Resin Solution 1 for Shell] was accurately weighed 0.9000 g to 1.0000 g in an aluminum container, left standing in a thermostatic bath set at an internal temperature of 150 °C for 1 hour, taken out from the thermostatic bath, and calculated from the remaining amount by the following formula. Solid content concentration [mass%] = (Remaining amount [g] after standing at 150 °C for 1 hour) / (Amount [g] of accurately weighed [Shell Resin Solution 1]) × 100

[0300] <Preparation of Shell Aqueous Phase 1> Mix and stir 468 parts by mass of water and 132 parts by mass of methyl ethyl ketone to obtain a white transparent liquid. This was designated as [Shell Aqueous Phase 1].

[0301] <Preparation of Polyester Resin Emulsion SR for Shell> While stirring 400 parts by mass of the solution of [Polyester Resin Solution 1 for Shell] with a TK homomixer (manufactured by Primix Corporation) at a rotation speed of 8,000 rpm, add 28% aqueous ammonia in an equivalent amount of 100% neutralization rate with respect to the acid value of [Polyester Resin SR for Shell], mix for 10 minutes, then gradually drop 600 parts by mass of [Shell Aqueous Phase 1] to phase-invert and emulsify [Polyester Resin Solution 1 for Shell]. Further, the phase-inverted and emulsified [Polyester Resin Solution 1 for Shell] was desolvated with an evaporator to obtain [Polyester Resin Emulsion SR for Shell].

[0302] <Preparation of WAX Dispersion 1> 720 parts by mass of deionized water was mixed with 180 parts by mass of ester wax (NOF Corporation, WE-11, synthetic wax from plant-derived monomers, melting point 67°C) and 17 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC, sodium dodecylbenzenesulfonate). This mixture was dispersed in a homogenizer while being heated to 90°C to obtain [WAX dispersion 1]. The volume-average particle size of the wax particles in the obtained [WAX dispersion 1] was 300 nm, and the solid content concentration of the wax dispersion was 25% by mass.

[0303] <Preparation of Masterbatch (MB) 1> 1200 parts by mass of water, 500 parts by mass of carbon black (Printex35, manufactured by Dexa) [DBP oil absorption = 42 mL / 100 mg, pH = 9.5], and 500 parts by mass of [amorphous polyester resin B-1] were added and mixed in a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd.). The mixture was kneaded at 150°C for 30 minutes using two rolls, then rolled and cooled, and pulverized in a pulperizer to obtain [Masterbatch 1].

[0304] (Particle manufacturing) [Base particle 1] <Oil phase preparation process> 50 parts by mass of [amorphous resin A-1], 50 parts by mass of [crystalline polyester resin dispersion C-1], 50 parts by mass of [WAX dispersion 1], 550 parts by mass of [amorphous polyester resin B-1], 300 parts by mass of [P-1], and 100 parts by mass of [masterbatch 1] were placed in a container and mixed at 5,000 rpm for 60 minutes using a TK homomixer (manufactured by Primix Co., Ltd.) to obtain [oil phase 1]. The above proportions indicate the amount of solids in each raw material.

[0305] <Aqueous phase preparation process> 990 parts by mass of water, 20 parts by mass of sodium dodecyl sulfate, and 90 parts by mass of ethyl acetate were mixed and stirred to obtain a milky white liquid. This was designated as [Aqueous Phase 1].

[0306] <Phase inversion emulsification process> [Oil phase 1] 700 parts by mass was stirred in a TK homomixer at a rotation speed of 8,000 rpm while 20 parts by mass of 28% aqueous ammonia was added and mixed for 10 minutes. Then, 1,200 parts by mass of [Aqueous phase 1] was gradually added dropwise to obtain [Emulsified slurry 1].

[0307] <Solvent removal process> [Emulsified slurry 1] was placed in a container equipped with a stirrer and thermometer, and the solvent was removed at 30°C for 180 minutes to obtain [solvent-removed slurry 1].

[0308] <Agglomeration process> [Solvent-removed slurry 1] 30 parts by mass of 5% calcium chloride solution was added dropwise to 1000 parts by mass of the slurry 1 as a flocculant and stirred for 5 minutes. The temperature was then raised to 60°C, and when the particle size reached 5.0 μm, 30 parts by mass of calcium chloride was added to complete the flocculation process, thereby obtaining [flocculated slurry 1].

[0309] In Example 7 only, the following shelling step was applied after the aggregation step, and the following fusion step and washing / drying step were performed on the obtained [slurry after shelling step] to obtain [matrix particles 7].

[0310] <Shelling process> To 1000 parts by mass of [Agglomerated Slurry 1], 80 parts by mass of [Polyester Resin Emulsion SR for Shells] (Solid content concentration 25% by mass) were added and stirred. A 20% by mass magnesium sulfate aqueous solution was slowly added dropwise at a rate of 1 part by mass / min until the particles in the system stopped Brownian motion as observed with an optical microscope, thereby obtaining [Agglomerated Slurry after Shelling Process].

[0311] <Fusing process> [Agglomerated slurry 1] or [Agglomerated slurry after shelling process] was heated at 70°C for 3 hours while being stirred to obtain [Dispersed slurry 1].

[0312] <Washing and drying process> After filtering 100 parts by mass of [dispersed slurry 1] under reduced pressure, the following operations (1) to (4) were repeated three times to obtain [filtered cake 1]. (1): 100 parts by mass of deionized water were added to the filter cake, mixed with a TK homomixer (rotating at 12,000 rpm for 10 minutes), and then filtered. (2): 100 parts by mass of a 10% sodium hydroxide aqueous solution was added to the filtered cake from (1), mixed with a TK homomixer (at a rotation speed of 12,000 rpm for 30 minutes), and then filtered under reduced pressure. (3): 150 parts by mass of 10% hydrochloric acid were added to the filtered cake from (2), mixed in a TK homomixer (at a rotation speed of 12,000 rpm for 20 minutes), and then filtered. (4): 300 parts by mass of deionized water were added to the filtration cake from (3), mixed with a TK homomixer (rotating at 12,000 rpm for 10 minutes), and then filtered.

[0313] <Classification process> The obtained [filtered cake 1] was dried in a circulating air dryer at 45°C for 48 hours, and then sieved through a mesh with a mesh opening of 75 μm to obtain [matrix particles 1].

[0314] [Material particles 2~7] Except for changing the amounts of recycled PET [P-1] and amorphous polyester [resin B-1] added to the preparation of [matrix particle 1] as shown in Table 1, the preparation was carried out in the same manner as for [matrix particle 1], and [matrix particle 2] to [matrix particle 7] were obtained. The resistance values ​​R2 [logΩcm] at 25°C and 50% humidity, and the resistance values ​​R4 [logΩcm] at 40°C and 70% humidity were measured for [matrix particle 1] to [matrix particle 7]. The results are shown in Table 1. Note that the value of "mass ratio of recycled PET in total resin [%]" is shown rounded to the nearest whole number.

[0315] [Resistance values ​​of parent particles 1-7] The resistance values ​​R2 [logΩcm] at 25°C and 50% humidity, and R4 [logΩcm] at 40°C and 70% humidity for parent particles 1-7 were measured using the following method. First, 3g of each parent particle was molded into a pellet shape with a diameter of 40mm and a thickness of approximately 2mm to prepare a sample for measurement. Each sample was prepared using a BRE-32 model from Maekawa Testing Machine MFG, with a pressure load of 6 MPa and a pressurization time of 1 minute. Each prepared sample was set on an SE-70 solid electrode (manufactured by Ando Electric Co., Ltd.). The Log value [logΩcm], which is the common logarithm of the resistance value when a 1 kHz AC current was applied between the electrodes, was measured using an AC bridge method measuring instrument consisting of a TR-10C dielectric loss meter, a WBG-9 oscillator, and a BDA-9 equilibrium point detector (all manufactured by Ando Electric Co., Ltd.). This allowed us to determine the resistance values ​​R2 [logΩcm] of parent particles 1-7 at 25°C and 50% humidity, and the resistance values ​​R4 [logΩcm] of parent particles 1-7 at 40°C and 70% humidity. The results are shown in Table 1.

[0316] [Table 1]

[0317] <<Preparation of external additive 1>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200, BET specific surface area 200m²) 2 100g of (manufactured by Tosoh Silica) was dispersed in 2L of water and heated to 85°C. Next, an aqueous aluminum chloride solution was added in an amount equivalent to 10% by mass of Al2O3 relative to the silica particles, and the pH was adjusted to 5.5 with an aqueous sodium hydroxide solution. After holding the mixture while stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized using a media-type fine grinder. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 1.

[0318] <<Preparation of external additive 2>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200, BET specific surface area 200m²) 2 100g of (manufactured by Tosoh Silica) was dispersed in 2L of water and heated to 85°C. Next, an aqueous zinc chloride solution was added in an amount equivalent to 10% by mass of ZnO relative to the silica particles, and the pH was adjusted to 8.0 with an aqueous sodium hydroxide solution. After holding the mixture while stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized using a media-type fine grinder. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 2.

[0319] <<Preparation of external additive 3>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200, BET specific surface area 200m²) 2 100g of (manufactured by Tosoh Silica) was dispersed in 2L of water and heated to 85°C. Next, an aqueous magnesium chloride solution was added in an amount equivalent to 10% by mass of MgO relative to the silica particles, and the pH was adjusted to 5.0 with an aqueous sodium hydroxide solution. After holding the mixture while stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized using a media-type fine grinder. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 3.

[0320] <<Preparation of external additive 4>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200, BET specific surface area 200m²) 2100g of (manufactured by Tosoh Silica) was dispersed in 2L of water and heated to 85°C. Next, an aqueous solution of iron chloride was added in an amount equivalent to 10% by mass in terms of FeO relative to the silica particles, and the pH was adjusted to 8.5 with an aqueous solution of sodium hydroxide. After holding with stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized using a media-type fine grinder. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 4.

[0321] <<Preparation of external additive 5>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200BET specific surface area 200m²) 2 100g of (manufactured by Tosoh Silica) was dispersed in 2L of water and heated to 85°C. Next, an aqueous solution of copper(II) chloride was added in an amount equivalent to 10% by mass in terms of CuO relative to the silica particles, and the pH was adjusted to 9.0 with an aqueous solution of sodium hydroxide. After holding with stirring for 30 minutes, the mixture was filtered and the residue on the filter media was washed with water to obtain a washed cake. Next, this washed cake was dried at 120°C and then pulverized using a media-type fine grinder. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 5.

[0322] <<Preparation of external additive 6>> First, 100g of titanium dioxide was dispersed in 2L of water and heated to 85°C. Next, an aqueous zinc chloride solution was added in an amount equivalent to 10% by mass of ZnO relative to the titanium particles. The pH was adjusted to 8.5 with an aqueous sodium hydroxide solution, and the mixture was held while stirring for 30 minutes. After filtration, the residue on the filter media was washed with water to obtain a washing cake. Next, this washing cake was dried at 120°C and then pulverized using a media-type pulverizer. Finally, 40g of the obtained powder was placed in a small mixer, 10g of isobutyltrimethoxysilane was added and mixed for 15 minutes, and then re-dried at 120°C to prepare external additive 6.

[0323] <<Preparation of external additive 7>> First, silica particles manufactured by the liquid phase method (NipSeal SP-200, BET specific surface area 200m²) 2 External additive 7 was prepared by placing 100g of (manufactured by Tosoh Silica) into a small mixer, adding 10g of isobutyltrimethoxysilane, mixing for 15 minutes, and then re-drying at 120°C.

[0324] The resistance values ​​R1 [logΩcm] for external additives 1 to 7 at 25°C and 50% humidity, and R3 [logΩcm] at 40°C and 70% humidity were measured. The results are shown in Table 2.

[0325] [Resistance values ​​for external additives 1-7] The resistance values ​​R1 [logΩcm] at 25°C and 50% humidity, and R3 [logΩcm] at 40°C and 70% humidity for external additives 1 to 7 were measured using the following method. First, 3g of each external additive was molded into pellets approximately 40mm in diameter and 2mm thick to prepare measurement samples. Each measurement sample was prepared using a BRE-32 model from Maekawa Testing Machine MFG, with a pressure of 6 MPa and a pressurization time of 1 minute. Each prepared measurement sample was set on an SE-70 solid electrode (manufactured by Ando Electric Co., Ltd.). The Log value [logΩcm] of the resistance when a 1 kHz AC current was applied between the electrodes was measured using an AC bridge method measuring instrument consisting of a TR-10C dielectric loss meter, a WBG-9 oscillator, and a BDA-9 equilibrium point detector (all manufactured by Ando Electric Co., Ltd.). This allowed us to determine the resistance values ​​R1 [logΩcm] at 25°C and 50% humidity, and R3 [logΩcm] at 40°C and 70% humidity for external additives 1 to 7. The results are shown in Table 2.

[0326] [Table 2]

[0327] To [matrix particle 1], 100 parts by mass of [matrix particle 1], 1.5 parts by mass of hydrophobic silica particles with an average particle size of 50 nm, and 1.0 part by mass of [external additive 1] were mixed using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) to obtain the particles of Example 1.

[0328] [Mother Particle 1] to [Mother Particle 7] and [External Additive 1] to [External Additive 7] were combined as shown in Table 3 to produce particles for Examples 2 to 7 and Comparative Examples 1 to 3, in the same manner as in Example 1.

[0329] The particles of Examples 1-7 and Comparative Examples 1-3 were evaluated for environmental adaptability, long-term charge stability, and charge environment stability based on the following evaluation criteria. The results are shown in Table 3.

[0330] [Table 3]

[0331] <Environmental compatibility> The environmental friendliness of the toner was evaluated based on the ratio of environmentally friendly resins in the toner, according to the following evaluation criteria. (Evaluation Criteria) A: More than 70% recycled resin B: Recycled resin is between 30% and less than 70% C: Recycled resin content is 1% or more but less than 30% D: Less than 1% recycled resin

[0332] <Static stability over time> A durability test was conducted using each developer, printing 100,000 consecutive character image patterns with an image area ratio of 12%, and the change in charge during this test was evaluated. A small amount of developer was taken from the developing sleeve, and the change in charge was determined by the blow-off method and evaluated according to the following criteria. A rating of "C" or higher was deemed suitable for use in this invention. [Evaluation Criteria] A: Change in charge is less than 3 μC / g B: Change in charge is between 3 μC / g and less than 6 μC / g C: Change in charge is between 6 μC / g and less than 10 μC / g D: Change in charge is 10 μC / g or more

[0333] <Static environment stability> The measurement method for the static charge environment stability is as follows: The sample is conditioned in an open system for at least 30 minutes under conditions of 23°C and 50% relative humidity (M / M environment). An initial 6,000g of carrier and 0.452g of toner are added to a stainless steel container, which is then sealed. The sample is then operated for 5 minutes at a scale of 150 using a YS-LD (Yayoi Corporation shaker), and triboelectrically charged by approximately 1,100 shakes. The static charge amount measured using a general blow-off method (Toshiba Chemical Corporation: TB-200) is defined as Q1, and the static charge amount measured in the same manner as Q1 under conditions of 35°C and 80% relative humidity is defined as Q2. The result is |Q1-Q2|. [Evaluation Criteria] A: Change in charge is less than 2 μC / g B: Change in charge is between 2 μC / g and less than 5 μC / g C: Change in charge is between 5 μC / g and less than 10 μC / g D: Change in charge is 10 μC / g or more

[0334] Table 3 shows that the particles from Examples 1 to 7 all received a rating of "C" or higher for environmental compatibility, static charge stability over time, and static charge environment stability, confirming that they are suitable for use in the present invention. In contrast, the particles obtained in Comparative Examples 1 to 3 received a rating of "D" for at least one of the following: environmental compatibility, static charge stability over time, and static charge environment stability, and were not suitable for use in the present invention.

[0335] From the above, it has been shown that particles satisfying the configuration of the present invention have a low environmental impact, excellent static charge stability over time, and excellent static charge stability even in high humidity environments.

[0336] Examples of the present invention are as follows: <1> Particles comprising a mother particle containing a resin mainly composed of polyester, and an external additive, The polyester comprises at least one of polyethylene terephthalate and polybutylene terephthalate. The aforementioned external additive is coated with a metal hydroxide, At 25°C and 50% humidity, the resistance of the external additive is R1 [logΩcm], and the resistance of the parent particles is R2 [logΩcm]. When the resistance of the external additive is R3 [logΩcm] and the resistance of the parent particles is R4 [logΩcm] at 40℃ and 70% humidity, A particle such that R1 ≤ R2 and R3 ≤ R4. <2> The aforementioned resistance value R1 [logΩcm] is 9.0 to 11.0, and the aforementioned resistance value R2 [logΩcm] is 11.5 or less. The above resistance value R3 [logΩcm] is 8.0 to 10.8, and the resistance value R4 [logΩcm] is 10.0 to 10.8. <1> The particles described. <3> The above metal is at least one selected from aluminum, zinc, magnesium, and copper. <1> or <2> The particles described. <4> The above external additive contains silica. <1> , <2> or <3> The particles described. <5> The mass ratio of polyethylene terephthalate and polybutylene terephthalate is 10% or more and less than 50% of the total resin. <1> , <2> , <3> or <4> The particles described. <6> The mass ratio of polyethylene terephthalate and polybutylene terephthalate is 20% or more and less than 35% of the total resin. <1> , <2> , <3> , <4> or <5> The particles described. <7> The aforementioned resistance value R1 [logΩcm] is 9.0 to 11.0, and the aforementioned resistance value R2 [logΩcm] is 11.3 or less. The above resistance value R3 [logΩcm] is 8.5 to 10.5, and the resistance value R4 [logΩcm] is 10.4 to 10.7. <1> , <2> , <3> , <4> , <5> or <6> The particles described. <8> the above <1> , <2> , <3> , <4> , <5> , <6> , or <7> Toner containing the particles described above. <9> the above <8> A developer containing the toner described above. <10> Electrostatic latent image carrier, An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, The electrostatic latent image formed on the electrostatic latent image carrier is <8> An image forming apparatus comprising a developing means that develops using the toner described in the description to form a toner image. <11> An electrostatic latent image formation step in which an electrostatic latent image is formed on an electrostatic latent image carrier, The electrostatic latent image formed on the electrostatic latent image carrier is <8> An image forming method comprising a developing step of developing using the toner described in the document to form a toner image.

[0337] the above <1> from <7> Any of the above particles <8> The toner, as above <9> The developer, the above <10> Image forming apparatus, the above <11> This image formation method solves the problems of the conventional method and achieves the objectives of the present invention. [Explanation of Symbols]

[0338] 160Y Sub-hopper (Yellow) 160C Sub-hopper (Cyan) 160M Sub-hopper (Magenta) 160K Sub-hopper (Black) 180Y Image Forming Unit (Yellow) 180C Image Forming Unit (Cyan) 180M Image Forming Unit (Magenta) 180K Image Forming Unit (Black) 210 Paper feed section 211 Paper feed cassette 212 Paper feed roller 220 Conveying section 221 Laura 222 Timing Roller 223 Paper output roller 224 Paper Output Tray 230 Image creation section 231Y Photoconductor Drum (Yellow) 231C Photoconductor Drum (Cyan) 231M Photoconductor Drum (Magenta) 231K Photoconductor Drum (Black) 232Y Charger (Yellow) 232C Charger (Cyan) 232M Charger (Magenta) 232K Charger (Black) 233 Exposure Unit 233a light source 233bY Polygon Mirror (Yellow) 233bC Polygon Mirror (Cyan) 233bM Polygon Mirror (Magenta) 233bK Polygon Mirror (Black) 234Y Toner Bottle (Yellow) 234C Toner Bottle (Cyan) 234M Toner Bottle (Magenta) 234K Toner Bottle (Black) 236Y Cleaning device (yellow) 236C Cleaning device (Cyan) 236M Cleaning Machine (Magenta) 236K Cleaning Device (Black) 240 Transfer section 241 Drive roller 242 Driven roller 243 Intermediate transfer belt 244 Primary Transfer Roller 244Y Primary Transfer Roller (Yellow) 244C Primary Transfer Roller (Cyan) 244M Primary Transfer Roller (Magenta) 244K Primary Transfer Roller (Black) 245 Secondary opposing roller 246 Secondary Transfer Roller 250 Fuser 251 Fixing belt 252 Pressure roller L Laser P paper [Prior art documents] [Patent Documents]

[0339] [Patent Document 1] Patent No. 6138021

Claims

1. Particles comprising a mother particle containing a resin mainly composed of polyester, and an external additive, The polyester comprises at least one of polyethylene terephthalate and polybutylene terephthalate. The aforementioned external additive is coated with a metal hydroxide, At 25°C and 50% humidity, the resistance of the external additive is R1 [log Ωcm], and the resistance of the parent particles is R2 [log Ωcm]. When the resistance value of the external additive is R3 [log Ωcm] and the resistance value of the parent particles is R4 [log Ωcm] at 40°C and 70% humidity, A particle such that R1 ≤ R2 and R3 ≤ R4.

2. The resistance value R1 [log Ωcm] is 9.0 to 11.0, and the resistance value R2 [log Ωcm] is 11.5 or less. The particle according to claim 1, wherein the resistance value R3 [log Ωcm] is 8.0 to 10.8 and the resistance value R4 [log Ωcm] is 10.0 to 10.

8.

3. The particle according to claim 1, wherein the metal is at least one selected from aluminum, zinc, magnesium, and copper.

4. The particles according to claim 1, wherein the external additive contains silica.

5. The particles according to claim 1, wherein the mass ratio of polyethylene terephthalate and polybutylene terephthalate is 10% or more and less than 50% of the total resin.

6. The particles according to claim 1, wherein the mass ratio of polyethylene terephthalate and polybutylene terephthalate is 20% or more and less than 35% of the total resin.

7. The resistance value R1 [log Ωcm] is 9.0 to 11.0, and the resistance value R2 [log Ωcm] is 11.3 or less. The particle according to claim 1, wherein the resistance value R3 [log Ωcm] is 8.5 to 10.5 and the resistance value R4 [log Ωcm] is 10.4 to 10.

7.

8. Toner comprising the particles described in any one of claims 1 to 7.

9. A developer comprising the toner described in claim 8.

10. Electrostatic latent image carrier, An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, An image forming apparatus comprising: developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner described in claim 8 to form a toner image.

11. An electrostatic latent image formation step in which an electrostatic latent image is formed on an electrostatic latent image carrier, An image forming method comprising a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner described in claim 8 to form a toner image.

Images