Toner, developer, toner storage unit, image forming apparatus, image forming method, method for manufacturing printed materials, and method for manufacturing toner.

Abstract

To provide a toner that offers excellent low-temperature fixation while simultaneously achieving both filming resistance in high-temperature, high-humidity environments and release properties during fixation. [Solution] A toner containing toner particles that include a polyester resin, an aromatic petroleum resin, and a mold release agent, A toner characterized in that, when the cross-section of the toner particles is observed with a scanning electron microscope, the domains of the release agent satisfy the following requirements. (Requirements) Each toner particle contains, on average, 2 to 8 release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1)

Description

Technical Field

[0001] The present invention relates to a toner, a developer, a toner container unit, an image forming apparatus, an image forming method, a method for manufacturing a printed matter, and a method for manufacturing a toner.

Background Art

[0002] Conventionally, in an electrophotographic apparatus, an electrostatic recording apparatus, or the like, an electrostatic latent image or a magnetic latent image is visualized by an electrostatic latent image developing toner (also referred to as "toner" in the present invention). For example, in the electrophotographic method, after forming an electrostatic latent image on a photoreceptor (also referred to as an "electrostatic latent image carrier" in the present invention), the electrostatic latent image is developed using a toner to form a toner image. The toner image is usually transferred onto a recording medium such as paper and fixed by a method such as heating.

[0003] In recent years, for the purpose of energy saving by reducing the energy required for fixing, low-temperature fixing of toner has been demanded. Furthermore, due to the requirements for higher speed and higher image quality of image forming apparatuses, combined with the diversification of the usage purposes of image forming apparatuses, the demand for low-temperature fixing of toner has been increasing. As a method for low-temperature fixing of toner, a technique of using an amorphous polyester resin and a crystalline polyester resin in combination is known.

[0004] For example, a pulverized toner has been disclosed that is manufactured by pulverizing and classifying a composition in which a styrene-based resin with a mass-average molecular weight (Mw) of more than 3000 is added to a mixture of a binder resin and a colorant, with the aim of providing a toner that is excellent in pulverization during production and has excellent fixing stability (see, for example, Patent Document 1). Also, a pulverized toner has been disclosed in which the maximum peak ratio of polyester resin and styrene resin has been identified by FT-IR, with the aim of providing a pulverized toner that can achieve both low-temperature fixing properties and heat-resistant storage properties (see, for example, Patent Document 2). Furthermore, a toner has been disclosed in which the ratio of the total cross-sectional area of ​​the toner particles to the major axis of the domain of the release agent is defined, with the aim of providing a toner that can achieve both release properties of the fixed image and suppression of image density reduction during continuous printing in low-temperature, low-humidity environments (see, for example, Patent Document 3). [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a toner that exhibits excellent low-temperature fixation properties and can simultaneously suppress filming in high-temperature, high-humidity environments and ensure good release properties during fixation. [Means for solving the problem]

[0006] The toner of the present invention, as a means for solving the aforementioned problems, has the following configuration. A toner containing toner particles that include a polyester resin, an aromatic petroleum resin, and a mold release agent, A toner characterized in that, when the cross-section of the toner particles is observed with a scanning electron microscope, the domains of the release agent satisfy the following requirements. (Requirements) Each toner particle contains, on average, 2 to 8 release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1) [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a toner that exhibits excellent low-temperature fixation properties and can simultaneously suppress filming in high-temperature and high-humidity environments and ensure good release properties during fixation. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing an example of an electrophotographic developing apparatus according to the present invention. [Figure 2] This is a schematic diagram showing an example of a developing apparatus used in the present invention. [Figure 3] This figure shows an example of an image forming apparatus having a developing device, as shown in Figure 3. [Figure 4] This figure shows another example of an image forming apparatus used in the present invention. [Figure 5] This figure shows another example of an image forming apparatus used in the present invention. [Modes for carrying out the invention]

[0009] Conventional toners, such as those described in the above-mentioned Patent Documents 1 to 3, are known to have problems such as image defects caused by filming, where wax or polyester resin with low heat resistance exposed on the toner surface adheres to the photoreceptor. This problem is particularly pronounced in high-temperature and high-humidity environments, and the image defects become even more noticeable when the printing area is small. On the other hand, reducing the amount of wax used presents a challenge in terms of release properties during fixing. The challenge has been to achieve both suppression of filming in high-temperature and high-humidity environments and good release properties during fixing.

[0010] In contrast to the above-mentioned prior art, the toner of the present invention is a toner comprising toner particles containing a polyester resin, an aromatic petroleum resin, and a mold release agent, The toner is characterized in that, when the cross-section of the toner particles is observed with a scanning electron microscope, the domains of the release agent satisfy the following requirements. (Requirements) Each toner particle contains, on average, 2 to 8 release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1) More specifically, by satisfying the above conditions, the toner of the present invention can achieve excellent low-temperature fixing properties, as well as suppression of filming in high-temperature and high-humidity environments and good release properties during fixing.

[0011] The details of the present invention are described below.

[0012] <Toner> The toner of the present invention comprises a polyester resin, a release agent, and an aromatic petroleum resin, and may optionally contain a colorant, an external additive, and other components. The toner of the present invention has toner particles that satisfy the following requirements when the cross-section of the toner particles is observed. (Requirements): On average, there are 2 to 8 release agent domains per toner particle, each having a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1)

[0013] In the present invention, it is extremely important that when the cross-section of the toner particles is observed, there are release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less. If a large number of toner particles contain release agent domains with a major axis of 400 nm or more and an aspect ratio greater than 0.7, deformation of the particles due to the release agent domains occurs during storage, leading to a decrease in toner fluidity and deterioration of toner cohesiveness. Furthermore, especially in high-temperature and high-humidity environments, toner adheres to the photoreceptor during actual printing, causing problems such as filming. By having release agent domains with an aspect ratio of 0.7 or less, filming caused by exposure at the toner interface during pulverization can be suppressed.

[0014] <Polyester resin> The polyester resin used in the toner of the present invention is not particularly limited and can be appropriately selected according to the purpose. However, the weight average molecular weight (Mw) is preferably 7,000 or more and 10,000 or less, more preferably 7,500 or more and 9,500 or less, and even more preferably 8,000 or more and 9,000 or more. When the weight average molecular weight (Mw) of the polyester resin is 7,000 or more, the deterioration of hot offset resistance due to low molecular weight components can be suppressed, and when it is 10,000 or less, the deterioration of wax dispersibility due to high molecular weight components can be suppressed.

[0015] The weight average molecular weight (Mw) / number average molecular weight (Mn) is preferably 5 or less, more preferably 4 or less. Also, it is preferably 1 or more, more preferably 2 or more. When the weight average molecular weight (Mw) / number average molecular weight (Mn) of the polyester resin is 1 or more, it shows stable fixing property from low temperature to high temperature, and when it is 5 or less, it is possible to suppress the occurrence of quality problems due to extremely low molecular weight components or extremely high molecular weight components. ​​​​​​​​Since the crystalline polyester resin has high crystallinity, it exhibits a heat melting property of showing a rapid viscosity change near the fixing start temperature. When such a crystalline polyester resin having such properties is used together with an amorphous polyester resin, the heat storage stability due to crystallinity is good until just before the melting start temperature, and at the melting start temperature, a rapid viscosity decrease (sharp meltability) occurs due to the melting of the crystalline polyester resin. Along with this, the crystalline polyester resin is compatible with the amorphous polyester resin and is fixed by rapidly decreasing the viscosity, so that a toner having good heat storage stability and low-temperature fixing property can be obtained. Also, the release width (the difference between the fixing lower limit temperature and the high-temperature offset generation temperature) becomes good. The crystalline polyester resin can be obtained from a polyhydric alcohol and a polyvalent carboxylic acid or its derivative such as a polyvalent carboxylic acid, a polyvalent carboxylic acid anhydride, or a polyvalent carboxylic acid ester. In the present invention, the crystalline polyester resin refers to a resin obtained from a polyhydric alcohol and a polyvalent carboxylic acid or its derivative such as a polyvalent carboxylic acid, a polyvalent carboxylic acid anhydride, or a polyvalent carboxylic acid ester as described above. Modified polyester resins (for example, prepolymers described later and resins obtained by subjecting the prepolymers to crosslinking and / or elongation reactions) do not belong to the crystalline polyester resin.

[0018] - Polyhydric alcohol - There is no particular limitation on the polyhydric alcohol, and it can be appropriately selected according to the purpose. Examples include diols and polyhydric alcohols having three or more valences. Examples of the diol include saturated aliphatic diols and the like. Examples of the saturated aliphatic diol include linear saturated aliphatic diols and branched saturated aliphatic diols. Among these, linear saturated aliphatic diols are preferable from the viewpoint of preventing a decrease in melting point due to a decrease in crystallinity, and linear saturated aliphatic diols having 2 to 12 carbon atoms are more preferable from the viewpoint of easy availability.

[0019] 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, 1,10-decanediol, and 1,12-dodecanediol are preferred because they result in high crystallinity of the crystalline polyester resin and excellent sharp-melt properties. These can be used individually or in combination of two or more.

[0020] Examples of trivalent or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These alcohols may be used individually or in combination of two or more.

[0021] -Polyhydric carboxylic acids- There are no particular restrictions on the polycarboxylic acid, and it can be appropriately selected depending on the purpose. Examples include divalent carboxylic acids and trivalent or higher carboxylic acids. These polycarboxylic acids may be used individually or in combination of two or more.

[0022] Examples of the aforementioned 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; and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid. Furthermore, their anhydrides and lower (1-3 carbon atoms) alkyl esters can also be used.

[0023] Examples of the trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and 1,2,4-naphthalentricarboxylic acid. Furthermore, their anhydrides and lower (1-3 carbon atom) alkyl esters can also be used.

[0024] In addition to saturated aliphatic dicarboxylic acids and aromatic dicarboxylic acids, the aforementioned polycarboxylic acids may also include dicarboxylic acids having a sulfonic acid group or dicarboxylic acids having a double bond.

[0025] The crystalline polyester resin 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. That is, the crystalline polyester resin preferably has constituent units derived from a saturated aliphatic dicarboxylic acid having 4 to 12 carbon atoms and constituent units derived from a saturated aliphatic diol having 2 to 12 carbon atoms. This is preferable because it exhibits high crystallinity and excellent sharp melt properties, thus providing excellent low-temperature fixability.

[0026] There are no particular restrictions on the melting point of the crystalline polyester resin, and it can be appropriately selected depending on the purpose, but it is preferably 60°C or higher and 80°C or lower. If the melting point of the crystalline polyester resin is 60°C or higher, it is preferable because it can suppress the decrease in the heat-resistant storage properties of the toner caused by the crystalline polyester resin melting at low temperatures. If the melting point of the crystalline polyester resin is 80°C or lower, it is preferable because it can suppress the decrease in the low-temperature fixing performance of the toner caused by insufficient melting of the crystalline polyester resin due to heating during fixing.

[0027] There are no particular restrictions on the molecular weight of the crystalline polyester resin, and it can be appropriately selected according to the purpose. However, from the viewpoint that a sharp molecular weight distribution and low molecular weight are excellent for low-temperature fixation, and that a large amount of low molecular weight components reduces heat resistance for storage, it is preferable that the soluble content of orthodichlorobenzene in the crystalline polyester resin, as measured by gel permeation chromatography (GPC), has a weight-average molecular weight (Mw) of 3,000 to 30,000, a number-average molecular weight (Mn) of 1,000 to 10,000, and an Mw / Mn ratio of 1.0 to 10. Furthermore, it is more preferable that the soluble content of orthodichlorobenzene in the crystalline polyester resin, as measured by gel permeation chromatography (GPC), has a weight-average molecular weight (Mw) of 5,000 to 15,000, a number-average molecular weight (Mn) of 2,000 to 10,000, and an Mw / Mn ratio of 1.0 to 5.0.

[0028] The number-average molecular weight (Mn) and the weight-average molecular weight (Mw) can be measured using gel permeation chromatography (GPC) under the following conditions, for example. —Measurement conditions— • Equipment (example): "HLC-8120" (manufactured by Tosoh Corporation) • Column (example): Two "TSK GEL GMH6" columns (manufactured by Tosoh Corporation) ·Measurement temperature: 40℃ • Sample solution: 0.25% by weight tetrahydrofuran solution (insoluble matter filtered out using a glass filter) ·Solution injection volume: 100μl • Detection device: Refractive index detector • Reference material: Standard polystyrene (TSKstandard POLYSTYRENE) 12 samples (molecular weight: 500, 1,050, 2,800, 5,970, 9,100, 18,100, 37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000) (manufactured by Tosoh Corporation)

[0029] There are no particular restrictions on the acid value of the crystalline polyester resin, and it can be appropriately selected according to the purpose. However, from the viewpoint of the affinity between the resin and the recording medium (paper, etc.), as described later, a value of 5 mg KOH / g or more is preferred, and 10 mg KOH / g or more is more preferred, in order to achieve the desired low-temperature fixation. On the other hand, to improve high-temperature offset resistance, a value of 45 mg KOH / g or less is preferred.

[0030] There are no particular restrictions on the hydroxyl value of the crystalline polyester resin, and it can be appropriately selected depending on the purpose. However, in order to achieve the desired low-temperature fixability and good electrostatic properties, a value of 0 mg KOH / g or more and 50 mg KOH / g or less is preferred, and 5 mg KOH / g or more and 50 mg KOH / g or less is more preferred.

[0031] The molecular structure of the crystalline polyester resin can be confirmed by NMR measurement in solution or solid state, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. A simple method is to detect crystalline polyester resins that have absorption based on δCH (out-of-plane bending vibration) of olefins at 965 cm⁻¹ ± 10 cm⁻¹ or 990 cm⁻¹ ± 10 cm⁻¹ in the infrared absorption spectrum.

[0032] There are no particular restrictions on the content of the crystalline polyester resin, and it can be appropriately selected depending on the purpose, but it is preferably 3 parts by mass or more and 20 parts by mass or less, and more preferably 5 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the toner. It is preferable that the content of the crystalline polyester resin is 3 parts by mass or more per 100 parts by mass of the toner, as this promotes sharp melting by the crystalline polyester resin and results in good low-temperature fixation. It is preferable that the content of the crystalline polyester resin is 20 parts by mass or less per 100 parts by mass of the toner, as this results in good heat resistance and the acquisition of high-quality images.

[0033] <Amorphous polyester resin> The amorphous polyester resin is not particularly limited and can be appropriately selected according to the purpose. Examples include amorphous polyester resin A having a glass transition temperature (Tg) of -40°C or higher and 20°C or lower, and amorphous polyester resin B having a glass transition temperature (Tg) of 40°C or higher and 80°C or lower.

[0034] -Amorphous polyester resin A- The amorphous polyester resin A is not particularly limited as long as its glass transition temperature (Tg) is between -40°C and 20°C, and can be appropriately selected according to the purpose. The amorphous polyester resin A is preferably obtained by a reaction between a nonlinear reactive precursor and a curing agent. Furthermore, the amorphous polyester resin A preferably has at least one of urethane bonds and urea bonds, as this provides superior adhesion to recording media such as paper. By having either urethane bonds or urea bonds, the amorphous polyester resin A exhibits behavior similar to that of pseudo-crosslinking points, thereby enhancing the rubbery properties of the amorphous polyester resin A and improving the heat resistance and high-temperature offset resistance of the toner.

[0035] --Nonlinear reactive precursor-- The nonlinear reactive precursor is not particularly limited as long as it is a polyester resin (sometimes referred to as "prepolymer") having a group that can react with the curing agent, and can be appropriately selected depending on the purpose. Here, "nonlinear" means having a branched structure conferred by at least one of a trivalent or higher alcohol and a trivalent or higher carboxylic acid. If the reactive precursor in the amorphous polyester resin A is nonlinear, it has a branched structure in its molecular backbone, and as a result the molecular chains take on a three-dimensional network structure, giving it rubber-like properties such as deforming at low temperatures but not flowing. Therefore, it is possible to maintain the heat resistance and high-temperature offset resistance of the toner.

[0036] Examples of groups in the prepolymer that can react with the curing agent include groups that can react with active hydrogen groups. 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 the amorphous polyester resin.

[0037] As the prepolymer, a polyester resin containing isocyanate groups is preferred. There are no particular limitations on the polyester resin containing the isocyanate group, and it can be appropriately selected depending on the purpose. For example, a reaction product of a polyester resin having an active hydrogen group and a polyisocyanate can be used. The polyester resin having an active hydrogen group 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 containing the isocyanate group.

[0038] The aforementioned diol is not particularly limited and can be appropriately selected depending on the purpose. Examples include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 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 polytetramethylene glycol. Examples include diols having an oxyalkylene group such as licol; 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. Among these, aliphatic diols with 4 to 12 carbon atoms are preferred. These diols may be used individually or in combination of two or more.

[0039] The dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples include aliphatic dicarboxylic acids and aromatic dicarboxylic acids. In addition, anhydrides of these dicarboxylic acids may be used, as well as lower (1-3 carbon atoms) alkyl esters or halides.

[0040] The aliphatic dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples include succinic acid, adipic acid, sebacic acid, dodecanediic acid, maleic acid, and fumaric acid. The aromatic dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, but aromatic dicarboxylic acids having 8 to 20 carbon atoms are preferred. The aromatic dicarboxylic acid having 8 to 20 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose, and examples include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc. Among these, aliphatic dicarboxylic acids with 4 to 12 carbon atoms are preferred. These dicarboxylic acids may be used individually or in combination of two or more.

[0041] There are no particular restrictions on the alcohols with a valency of 3 or higher, and they can be appropriately selected depending on the purpose. Examples include aliphatic alcohols with a valency of 3 or higher, polyphenols with a valency of 3 or higher, and alkylene oxide adducts of polyphenols with a valency of 3 or higher. Examples of trivalent or higher aliphatic alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol. Examples of the aforementioned polyphenols with a valency of 3 or higher include trisphenol PA, phenol novolac, and cresol novolac. Examples of alkylene oxide adducts of polyphenols with a valency of 3 or higher include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide to polyphenols with a valency of 3 or higher.

[0042] The amorphous polyester resin A preferably contains a trivalent or higher aliphatic alcohol as a constituent component. The amorphous polyester resin A, by containing trivalent or higher aliphatic alcohols as a constituent component, has a branched structure in its molecular backbone, and its molecular chains form a three-dimensional network structure. As a result, it deforms at low temperatures but does not flow, exhibiting rubber-like properties. Therefore, it is possible to maintain the heat resistance and high-temperature offset resistance of the toner.

[0043] The amorphous polyester resin A can also use trivalent or higher carboxylic acids or epoxy as crosslinking components. However, in the case of carboxylic acids, they are often aromatic compounds, and the density of ester bonds in the crosslinked portion becomes high, which can result in insufficient gloss in the fixed image created by heat-fixing the toner. When using crosslinking agents such as epoxy, the crosslinking reaction must be carried out after the polymerization of the polyester, making it difficult to control the distance between crosslinking points. This can result in the inability to obtain the desired viscoelasticity, and because the oligomers produced during polyester formation tend to react with the resin, creating areas with high crosslink density, the fixed image may become uneven, resulting in poor gloss and image density.

[0044] There are no particular restrictions on the trivalent or higher carboxylic acid, and it can be appropriately selected depending on the purpose. Examples include trivalent or higher aromatic carboxylic acids. In addition, anhydrides of these compounds may be used, as well as lower (1-3 carbon atoms) alkyl esters or halides. As the aforementioned trivalent or higher aromatic carboxylic acid, a trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms is preferred. Examples of such trivalent or higher aromatic carboxylic acids having 9 to 20 carbon atoms include trimellitic acid and pyromellitic acid.

[0045] There are no particular restrictions on the polyisocyanate, and it can be appropriately selected depending on the purpose. Examples include diisocyanates and isocyanates with a valentity of 3 or higher.

[0046] Examples of the diisocyanates include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aromatic aliphatic diisocyanates, isocyanurates, and those obtained by blocking these with phenol derivatives, oximes, caprolactams, etc.

[0047] The aliphatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples include tetramethylene diisocyanate, hexamethylene diisocyanate, methyl 2,6-diisocyanatocaproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, and tetramethylhexane diisocyanate.

[0048] There are no particular restrictions on the alicyclic diisocyanate, and it can be appropriately selected depending on the purpose. Examples include isophorone diisocyanate and cyclohexylmethane diisocyanate.

[0049] The aromatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples include tolylene diisocyanate, diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 4,4'-diisocyanato-3-methyldiphenylmethane, and 4,4'-diisocyanato-diphenyl ether.

[0050] The aforementioned aromatic aliphatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples include α,α,α',α'-tetramethylxylylene diisocyanate.

[0051] The isocyanurates mentioned above are not particularly limited and can be appropriately selected depending on the purpose. Examples include tris(isocyanatoalkyl)isocyanurate and tris(isocyanatocycloalkyl)isocyanurate. These polyisocyanates may be used individually or in combination of two or more.

[0052] --Hardening agent-- The curing agent is not particularly limited as long as it reacts with the nonlinear reactive precursor to produce the amorphous polyester resin A, and can be appropriately selected according to the purpose. Examples include active hydrogen group-containing compounds.

[0053] The active hydrogen group in the active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose. Examples include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, and mercapto groups. These may be used individually or in combination of two or more. The active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose, but amines are preferred because they can form urea bonds.

[0054] The aforementioned amines are not particularly limited and can be appropriately selected depending on the purpose. Examples include diamines, trivalent or higher amines, amino alcohols, amino mercaptans, amino acids, and those in which the amino group has been blocked. Among these, diamines and mixtures of diamines and small amounts of trivalent or higher amines are preferred. These can be used individually or in combination of two or more.

[0055] The diamine is not particularly limited and can be appropriately selected depending on the purpose. Examples include aromatic diamines, alicyclic diamines, and aliphatic diamines. There are no particular restrictions on the aromatic diamine, and it can be appropriately selected depending on the purpose. Examples include phenylenediamine, diethyltoluenediamine, and 4,4'-diaminodiphenylmethane. There are no particular restrictions on the alicyclic diamine, and it can be appropriately selected depending on the purpose. Examples include 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, diaminocyclohexane, and isophorone diamine. There are no particular restrictions on the aliphatic diamine, and it can be appropriately selected depending on the purpose. Examples include ethylenediamine, tetramethylenediamine, and hexamethylenediamine.

[0056] There are no particular restrictions on the amines with a valency of 3 or higher, and they can be appropriately selected depending on the purpose. Examples include diethylenetriamine and triethylenetetramine.

[0057] The amino alcohol is not particularly limited and can be appropriately selected depending on the purpose; examples include ethanolamine and hydroxyethylaniline.

[0058] The amino mercaptan mentioned above is not particularly limited and can be appropriately selected depending on the purpose. Examples include aminoethyl mercaptan and aminopropyl mercaptan.

[0059] There are no particular restrictions on the amino acids mentioned above, and they can be appropriately selected depending on the purpose. Examples include aminopropionic acid and aminocaproic acid.

[0060] There are no particular limitations on the amino group that is blocked, and it can be appropriately selected depending on the purpose. Examples include ketimine compounds and oxazoline compounds obtained by blocking the amino group with ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0061] The amorphous polyester resin A contains a diol component as a constituent, and it is preferable that the diol component contains 50% by mass or more of an aliphatic diol having 4 to 12 carbon atoms. Such amorphous polyester resin A is preferable because it can lower the glass transition temperature (Tg) and impart toner the property of deforming at low temperatures.

[0062] The amorphous polyester resin A preferably contains 50% by mass or more of aliphatic diols having 4 to 12 carbon atoms in the total alcohol component. Such amorphous polyester resin A is preferable because it can lower the glass transition temperature (Tg) and impart toner the property of deforming at low temperatures.

[0063] The amorphous polyester resin A preferably contains a dicarboxylic acid component, and the dicarboxylic acid component preferably contains 50% by mass or more of an aliphatic dicarboxylic acid having 4 to 12 carbon atoms. Such amorphous polyester resin A is preferable because it can lower the glass transition temperature (Tg) and impart toner the property of deforming at low temperatures.

[0064] The weight-average molecular weight of the amorphous polyester resin A is not particularly limited and can be appropriately selected depending on the purpose, but in GPC (gel permeation chromatography) measurement, it is preferably 20,000 to 1,000,000, more preferably 50,000 to 300,000, and particularly preferably 100,000 to 200,000. If the weight-average molecular weight of the amorphous polyester resin A is 20,000 or more, it is preferable because it can resolve problems such as the toner becoming more fluid at low temperatures, resulting in poor heat resistance during storage, and problems such as reduced viscosity during melting and decreased high-temperature offset properties.

[0065] The molecular structure of the amorphous polyester resin A can be confirmed by NMR measurement in solution or solid form, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. A simple method involves detecting amorphous polyester resin A by identifying materials that do not have absorption based on δCH (out-of-plane bending vibration) of olefins at 965±10 cm⁻¹ and 990±10 cm⁻¹ in the infrared absorption spectrum.

[0066] There are no particular restrictions on the content of the amorphous polyester resin A, and it can be appropriately selected depending on the purpose, but it is preferably 5 parts by mass or more and 25 parts by mass or less, and more preferably 10 parts by mass or more and 20 parts by mass or less, per 100 parts by mass of the toner. The content of the amorphous polyester resin A is preferably 5 parts by mass or more per 100 parts by mass of the toner, as this results in good low-temperature fixing properties and high-temperature offset resistance. The content of the amorphous polyester resin A is preferably 25 parts by mass or less per 100 parts by mass of the toner, as this results in good heat resistance for storage and good glossiness of the image obtained after fixing. In other words, when the content of the amorphous polyester resin A is within the above preferred range, it is advantageous in that it is excellent in all aspects of low-temperature fixing properties, high-temperature offset resistance, and heat-resistant storage properties.

[0067] --Amorphous polyester resin B-- The amorphous polyester resin B is not particularly limited as long as its glass transition temperature (Tg) is between 40°C and 80°C, and can be appropriately selected according to the purpose.

[0068] The amorphous polyester resin B is preferably a linear polyester resin. The amorphous polyester resin B is preferably free from urethane and urea bonds.

[0069] The amorphous polyester resin B is preferably an unmodified polyester resin. The aforementioned unmodified polyester resin refers to a polyester resin obtained using a polyhydric alcohol and a polyhydric acid such as a polyhydric carboxylic acid, polyhydric carboxylic acid anhydride, or polyhydric carboxylic acid ester, or a derivative thereof, which has not been modified with an isocyanate compound or the like.

[0070] Examples of the aforementioned polyhydric alcohols include diols. Examples of such 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; 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 can be used individually or in combination of two or more.

[0071] Examples of the polycarboxylic acid include dicarboxylic acids. Examples of such dicarboxylic acids include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid; and succinic acid substituted with alkyl groups having 1 to 20 carbon atoms or alkenyl groups having 2 to 20 carbon atoms, such as dodecenyl succinic acid and octyl succinic acid. These can be used individually or in combination of two or more.

[0072] The 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. Such amorphous polyester resins are advantageous in terms of heat resistance and storage properties.

[0073] The 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 for the purpose of adjusting the acid value and hydroxyl value. Examples of carboxylic acids with a valency of 3 or higher include trimellitic acid, pyromellitic acid, or their acid anhydrides. Examples of alcohols with a hydride of 3 or higher include glycerin, pentaerythritol, and trimethylolpropane.

[0074] The molecular weight of the amorphous polyester resin B is not particularly limited and can be appropriately selected according to the purpose. However, in GPC (gel permeation chromatography) measurements, the weight-average molecular weight (Mw) is preferably 3,000 to 10,000, more preferably 4,000 to 7,000, the number-average molecular weight (Mn) is preferably 1,000 to 4,000, more preferably 1,500 to 3,000, and the Mw / Mn ratio is preferably 1.0 to 4.0, more preferably 1.0 to 3.5. If the molecular weight of the amorphous polyester resin B is too low, the toner may have poor heat resistance during storage and poor durability against stress such as agitation in the developing machine. Conversely, if the molecular weight is too high, the viscoelasticity of the toner during melting may increase, resulting in poor low-temperature fixation. The above preferred numerical range is preferable as it can resolve the above problems.

[0075] The acid value of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 1 mg KOH / g or more and 50 mg KOH / g or less, and more preferably 5 mg KOH / g or more and 30 mg KOH / g or less. When the acid value of the amorphous polyester resin B is 1 mg KOH / g or higher, the toner tends to become negatively charged, and furthermore, when fixed to a recording medium such as paper, the affinity between the recording medium and the toner is improved, thereby improving low-temperature fixing performance. When the acid value of the amorphous polyester resin B is 50 mgKOH / g or less, the electrostatic stability, particularly the electrostatic stability against environmental changes, is good.

[0076] The hydroxyl value of the amorphous polyester resin B is not particularly limited and can be appropriately selected depending on the purpose, but 5 mg KOH / g or higher is preferred.

[0077] The glass transition temperature (Tg) of the amorphous polyester resin B is 40°C or higher and 80°C or lower, and more preferably 50°C or higher and 70°C or lower. The fact that the amorphous polyester resin B has a glass transition temperature of 40°C or higher is preferable because it provides sufficient heat resistance for toner storage and durability against stress such as agitation in the developing machine, as well as good filming resistance. The fact that the amorphous polyester resin B has a glass transition temperature of 80°C or lower is preferable because it allows for sufficient deformation due to heating and pressurization during toner fixing, resulting in good low-temperature fixing performance.

[0078] There are no particular restrictions on the method for measuring the glass transition temperature (Tg) of the amorphous polyester resin A and the amorphous polyester resin B, and a suitable method can be selected depending on the purpose. For example, it can be measured using a differential scanning calorimeter (Q-200, manufactured by TA Instruments). An example of a specific measurement method is as follows. [An example of a method for measuring the glass transition temperature (Tg)] Approximately 5.0 mg of the target sample is placed in an aluminum sample container, which is then placed on a holder unit and set in an electric furnace. Next, under a nitrogen atmosphere, the temperature is increased from -80°C to 150°C at a heating rate of 10°C / min. The glass transition temperature (Tg) of the target sample is then determined from the resulting DSC curve using an analysis program in a differential scanning calorimeter.

[0079] The molecular structure of the amorphous polyester resin B can be confirmed by NMR measurement in solution or solid state, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. A simple method is to detect amorphous polyester resins in the infrared absorption spectrum if they do not have absorption based on δCH (out-of-plane bending vibration) of olefins at 965±10 cm⁻¹ and 990±10 cm⁻¹.

[0080] There are no particular restrictions on the content of the amorphous polyester resin B, and it can be appropriately selected depending on the purpose, but it is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the toner. When the content of the amorphous polyester resin B is 50 parts by mass or more per 100 parts by mass of the toner, the dispersibility of the pigment and release agent in the toner is improved, which is preferable as it can suppress the occurrence of image fringing and distortion. When the content of the amorphous polyester resin B is 90 parts by mass or more per 100 parts by mass of the toner, the content of the crystalline polyester resin C and the amorphous polyester resin A becomes appropriate, resulting in good low-temperature fixing properties, which is preferable. When the content of the amorphous polyester resin B is 60 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the toner, it is advantageous in that it is superior in both high image quality and low-temperature fixing performance.

[0081] From the viewpoint of further improving low-temperature fixation performance, it is preferable to use the amorphous polyester resin A and the crystalline polyester resin C in combination. From the viewpoint of achieving both low-temperature fixation and high-temperature, high-humidity storage, it is preferable that the amorphous polyester resin A has a low glass transition temperature. A low glass transition temperature of the amorphous polyester resin A is preferable because it deforms under heating and pressure during fixation, making it easier to adhere to recording media such as paper at lower temperatures.

[0082] <Toner acid value> Furthermore, the acid value of the toner of the present invention is preferably 6 mg KOH / g or more and 12 mg KOH / g or less. During fixing, the acidic groups in the polyester resin and the aromatic petroleum resin described later become appropriately compatible, allowing the aromatic petroleum resin to be present at the interface between the binder resin and the release agent particle domain. If the acid value exceeds 12 mgKOH / g, the aromatic petroleum resin becomes miscible, making it easier for the release agent particles to exist independently, which may result in poor photoreceptor filming. If the acid value falls below 6 mgKOH / g, the affinity for the aromatic petroleum resin decreases, making it easier for the release agent particles to exist independently, which may result in poor photoreceptor filming.

[0083] The acid value of the aforementioned toner shall be measured under the following conditions in accordance with the measurement method described in JIS K0070-1992. Sample preparation: Add 0.5 g of toner to 120 mL of toluene and stir at room temperature (23°C) for approximately 10 hours to dissolve. Then add 30 mL of ethanol to prepare the sample solution. The measurement can be performed using the aforementioned apparatus, but specifically, the calculation is performed as follows: The acid value is determined by titrating with a pre-standardized N / 10 potassium hydroxide-alcohol solution and calculating the amount of potassium alcohol solution consumed. Acid value = KOH (number of mL) × N × 56.1 / sample mass (where N is the factor of N / 10KOH)

[0084] The acid value of the aforementioned toner is determined by the following procedure. Measurement device: Potentiometric automatic titrator DL-53 Titrator (manufactured by Mettler-Toledo) Electrode used: DG113-SC (Mettler-Toledo) Analysis software: LabX Light Version 1.00.000 Calibration of the instrument: Use a mixed solvent of 120 mL of toluene and 30 mL of ethanol. Measurement temperature: 23℃ The measurement conditions are as follows: Stirring conditions Stirring speed [%]:25 Stirring time [s]: 15 Equilibrium titration conditions Titrant: CH3ONa Concentration [mol / L]:0.1 Electrode:DG115 Measurement unit: mV Titrant drop before measurement Dripping amount [mL]: 1.0 Waiting time [s]: 0 Titration mode: Dynamic dE(set)[mV]:8.0 dV(min)[mL]:0.03 dV(max)[mL]:0.5 Measurement mode: Equilibrium titration dE[mV]:0.5 dt[s]:1.0 t(min)[s]:2.0 t(max)[s]:20.0 Recognition conditions Threshold: 100.0 Maximum rate of change only: No Range: No Frequency: None Measurement termination conditions Maximum dripping amount [mL]: 10.0 Potential: No Gradient: No After the equivalence point: Yes n: 1 Combination of termination conditions: No Evaluation conditions Procedure: Standard Potential 1: No Potential 2: No Stop for re-evaluation: No

[0085] <Hydroxyl value of toner> Furthermore, the hydroxyl value of the toner of the present invention is preferably 25 mg KOH / g or more and 45 mg KOH / g or less. More preferably, it is 30 mg KOH / g or more and 40 mg KOH / g or less. If the hydroxyl value is higher than 45 mg KOH / g, it will adsorb moisture in high temperature and high humidity environments, reducing the amount of charge and causing abnormal images such as background smudges and toner scattering. If the hydroxyl value is lower than 25 mg KOH / g, the adhesion between the resin and paper will decrease, and low-temperature adhesion and offset resistance will decrease.

[0086] The hydroxyl value of the aforementioned toner shall be measured under the following conditions in accordance with the measurement method described in JIS K0070-1992. Sample preparation: (1) Preparation of a 0.5 mol / L potassium hydroxide titration solution Dissolve 40g of potassium hydroxide in 50ml of deionized water. Discard 10ml of the supernatant of the prepared potassium hydroxide solution, then add methanol to make a total volume of 1000ml. (2) Preparation of methanol-acetone mixed solution Mix 1 L of methanol and 1 L of acetone, add 1 drop of BTB reagent and 30 ml of PP indicator, then add 0.1 mol / L potassium hydroxide methanol solution until it turns a faint reddish-purple color. (3) Place 5g of toner in an Erlenmeyer flask, add 5ml of anhydrous acetic acid / pyridine (1:4) mixture using a volumetric pipette, and then add 25ml of pyridine using a graduated cylinder. Attach a condenser to this and react in a 98°C oil bath for 1.5 hours. (4) Add 3 ml of deionized water from the top of the cooling tube and heat in the oil bath for another 10 minutes. (5) Remove the Erlenmeyer flask from the oil bath and let it cool to room temperature. Then, rinse the condenser with acetone and remove the condenser. (6) Add 50 ml of tetrahydrofuran using a graduated cylinder, add 10 drops of PP indicator, and titrate with the 0.5 mol / L potassium hydroxide titration solution prepared in (1). Near the endpoint, add 25 ml of the methanol-acetone mixture prepared in (2) and continue titration. Determine the quantitative determination at the point where a faint pink color persists for 30 seconds. (7) Perform the above steps (3) to (6) without a sample to create a blank test. (8) The hydroxyl value is calculated using the following formula. Hydroxyl value = [(BA) × f × 28.05 / S] + Acid value A: The titration volume of 0.5 mol / L potassium hydroxide titrant used in this test. • B: Titration volume of 0.5 mol / L potassium hydroxide titration solution required for the test. • f: Factor of 0.5 mol / L potassium hydroxide titration solution ·S: Sample collection amount (g)

[0087] <Release agent> There are no particular limitations on the release agent used in the toner of the present invention, and it can be appropriately selected according to the purpose. Examples of waxes and 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 selsine; and natural waxes such as petroleum waxes such as paraffin, microcrystalline, and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene, and polypropylene; and synthetic waxes such as esters, ketones, and ethers can also be used.

[0088] Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalimide 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-ethyl methacrylate); and crystalline polymers having long alkyl groups in their side chains can also be used. Among these, hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax are preferred from the viewpoint of being able to suppress the occurrence of filming.

[0089] Hydrocarbon waxes have low compatibility with general polyester resins, so they tend to seep to the surface during fixing, exhibiting high release properties and ensuring high gloss and excellent low-temperature fixing. There are no particular restrictions on the melting point of the release agent used in the toner of the present invention, and it can be appropriately selected depending on the purpose, but it is preferable that the melting point is 80°C or higher and 100°C or lower. If the melting point is 80°C or higher, heat resistance for storage can be ensured, and if the melting point is 100°C or lower, low-temperature fixation can be ensured.

[0090] Furthermore, there are no particular restrictions on the content of the release agent in the toner of the present invention, and it can be appropriately selected depending on the purpose. However, it is preferable that the release agent content be 2 parts by mass or more and 6 parts by mass or less, and more preferably 3 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the total amount of binder resin, release agent and aromatic petroleum resin contained in the toner. When the release agent content is 2 parts by mass or more per 100 parts by mass of the total amount of binder resin, release agent and aromatic petroleum resin contained in the toner, sufficient seepage to the surface during fixing is achieved, resulting in good release properties and ensuring low-temperature fixing properties and high-temperature offset resistance. When it is 6 parts by mass or less, the amount of release agent deposited on the toner surface does not increase excessively, ensuring the storage properties and fluidity of the toner, preventing deterioration of filming resistance to electrostatic latent image carriers, etc., and ensuring the transportability of residual toner.

[0091] <Aromatic petroleum resin> The aromatic petroleum resin used in the toner of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of balancing compatibility and incompatibility with polyester resin, styrene resins are preferred.

[0092] Examples of styrene-based resins include polymers of styrene and its substituted products such as polystyrene, poly-p-styrene, and polyvinyltoluene; styrene-α-methylstyrene copolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer.

[0093] <<Glass transition temperature (Tg) of aromatic petroleum resins>> Furthermore, the glass transition temperature Tg of the aromatic petroleum resin used in the present invention is preferably 70°C or higher and 90°C or lower, more preferably 75°C or higher and 90°C or lower, and even more preferably 80°C or higher and 90°C or lower. A glass transition temperature of 70°C or higher ensures the heat resistance of the toner for storage, and a glass transition temperature of 90°C or lower ensures low-temperature fixing performance.

[0094] The glass transition temperature (Tg) in this invention can be measured, for example, using a differential scanning calorimeter (DSC210, manufactured by Seiko Electronics Co., Ltd.). Specifically, for example, using a differential scanning calorimeter (DSC210, manufactured by Seiko Electronics Co., Ltd.), 0.01 g to 0.02 g of the sample is weighed into an aluminum pan and heated to 150°C. The sample is then cooled to 20°C at a rate of 10°C / min and heated again at a rate of 10°C / min. The temperature at the intersection of the baseline extension below the highest endothermic peak temperature and the tangent line showing the maximum slope from the peak rise to the peak apex can be defined as the glass transition temperature (Tg).

[0095] There are no particular restrictions on the content of aromatic petroleum resin in the toner of the present invention, and it can be appropriately selected depending on the purpose. However, it is preferably 7 parts by mass or more and 9.5 parts by mass or less, and more preferably 6 parts by mass or more and 8 parts by mass or less, per 100 parts by mass of the total amount of binder resin, release agent and aromatic petroleum resin contained in the toner. When the content of aromatic petroleum resin is 7 parts by mass or more per 100 parts by mass of the total amount of binder resin, release agent and aromatic petroleum resin contained in the toner, the decrease in pulverability when the kneaded toner material is pulverized can be suppressed and the productivity of the pulverized toner material knead can be ensured. When it is 9.5 parts by mass or less, the low-temperature fixing properties of the resulting toner can be ensured.

[0096] <Coloring agent> Examples of colorants include 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, red iron oxide, red lead, red lead, ka Dominum Red, Cadmium Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise 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, Pigment Scarlet 3B, Vol Do 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 -Ki, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine, navy 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, lithopone, and mixtures thereof can be used. The amount used is generally 0.1 parts by mass to 80 parts by mass per 100 parts by mass of binder resin.

[0097] Furthermore, the toner of the present invention preferably has an average circularity of 0.93 or more and 0.96 or less.

[0098] <External Additives> External additives may include, for example, abrasives such as silica, Teflon® resin powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder, and strontium titanate powder; fluidity enhancers such as titanium oxide powder and aluminum oxide powder; anti-aggregation agents and resin powders; or conductivity enhancers such as zinc oxide powder, antimony oxide powder, and tin oxide powder. Reverse polarity white and black fine particles may also be used as developability enhancers. These can be used individually or in combination and are selected to provide resistance to developing stress such as idling.

[0099] <Developer> When using a two-component developer system, the magnetic nanoparticles used as magnetic carriers can include magnetite, spinel ferrite such as gamma iron oxide, spinel ferrite containing one or more metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.), magnetoplanvite-type ferrites such as barium ferrite, and iron or alloy particles with an oxide layer on their surface. Their shape can be granular, spherical, or needle-shaped. In particular, when high magnetization is required, it is preferable to use ferromagnetic nanoparticles such as iron. Furthermore, considering chemical stability, it is preferable to use magnetite, spinel ferrite containing gamma iron oxide, or magnetoplanvite-type ferrites such as barium ferrite. By selecting the type and content of ferromagnetic nanoparticles, a resin carrier with the desired magnetization can also be used. In this case, the magnetic properties of the carrier are preferably such that the magnetization strength at 1,000 oorsted is 30 emu / g to 150 emu / g.

[0100] Such resin carriers can be manufactured by spraying a molten mixture of magnetic microparticles and an insulating binder resin using a spray dryer, or by reacting and curing a monomer or prepolymer in an aqueous medium in the presence of magnetic microparticles, thereby producing a resin carrier in which magnetic microparticles are dispersed in a condensation-type binder.

[0101] The chargeability of a magnetic carrier can be controlled by fixing positively or negatively charged microparticles or conductive microparticles to the surface, or by coating it with a resin. Silicone resins, acrylic resins, epoxy resins, and fluororesins can be used as coating materials for the magnetic carrier surface, but silicone resins and acrylic resins are preferred. These resins, or resins further containing positively or negatively charged fine particles or conductive fine particles, can be used as coating materials to coat the magnetic carrier surface. The mixing ratio of the electrophotographic toner and magnetic carrier in the present invention is preferably 2% by mass or more and 10% by mass or less in terms of toner concentration.

[0102] Furthermore, the weight-average particle size of the toner is preferably between 2 μm and 10 μm. The particle size of the toner is measured by various methods. For example, using the Coulter Counter Multisizer III, the measurement sample is prepared by adding the toner to an electrolyte solution containing a surfactant, dispersing it in an ultrasonic disperser for 1 minute, and then measuring 50,000 samples.

[0103] To produce the electrostatic image developing toner according to the present invention, a fixing resin, lubricant, colorant if necessary, and a fixed resin in which a charge control agent, lubricant, and additives are uniformly dispersed are combined and thoroughly mixed in a mixer such as a Henschel mixer or super mixer. Then, the mixture is melt-kneaded using a hot-melt kneader such as a heated roll, kneader, or extruder to thoroughly mix the materials. After cooling and solidifying, the toner is finely ground and classified to obtain the toner. As for the grinding method at this time, a jet mill method in which the toner is contained in a high-speed airflow and ground by the energy of impacting the toner against an impact plate, an interparticle impact method in which toner particles collide with each other in an airflow, and a mechanical grinding method in which the toner is supplied between a high-speed rotating rotor and a narrow gap for grinding can be used.

[0104] <Image forming apparatus and image forming method> 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, 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 on the electrostatic latent image carrier, a transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The apparatus may further include other means such as static elimination means, cleaning means, recycling means, and control means as needed.

[0105] 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, 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 on the electrostatic latent image carrier, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium, and may further include other steps such as a static elimination step, a cleaning step, a recycling step, and a control step as needed.

[0106] -Electrostatic latent image formation process and electrostatic latent image formation means- The electrostatic latent image formation step is a step of forming an electrostatic latent image on an electrostatic latent image carrier. The electrostatic latent image forming means is a means for forming an electrostatic latent image on an electrostatic latent image carrier. The electrostatic latent image formation process can be suitably carried out by the electrostatic latent image formation means.

[0107] The electrostatic latent image carrier (hereinafter sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") is not particularly limited in terms of material, shape, structure, size, etc., and can be appropriately selected from known materials. However, a drum shape is preferred, and examples of materials include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine.

[0108] Examples of the organic photoreceptor include a laminated photoreceptor having a laminated structure in which a layer in which a charge-generating material such as metal-free phthalocyanine or titanylphthalocyanine is dispersed in a binder resin (charge-generating layer) and a layer in which a charge-transporting material is dispersed in a binder resin (charge-transporting layer) are stacked on a support such as an aluminum drum, and a single-layer photoreceptor having a single-layer photoreceptor in which both a charge-generating material and a charge-transporting material are dispersed in a binder resin on a support. In single-layer photoreceptors, hole transporters and electron transporters can be added to the photosensitive layer as charge transport materials. Furthermore, an undercoat layer may be provided between the support and the multilayer charge generation layer or the single-layer photosensitive layer.

[0109] The electrostatic latent image can be formed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it to light in an image-like manner.

[0110] Preferably, the electrostatic latent image forming means includes at least a charging means (charger) for uniformly charging the surface of the electrostatic latent image carrier, and an exposure means (exposure unit) for exposing the surface of the electrostatic latent image carrier to an image-like state.

[0111] The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger. There are no particular limitations on the aforementioned charger, and it can be appropriately selected according to the purpose. Examples include contact chargers that are known themselves and equipped with conductive or semiconductive rolls, brushes, films, rubber blades, etc., and non-contact chargers that utilize corona discharge such as Corotron and Scorotron.

[0112] 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.

[0113] The 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. The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier, which has been charged by the charger, in the manner of the image to be formed. It can be appropriately selected according to the purpose, and examples of various exposure devices include copying optical systems, rod lens array systems, laser optical systems, and liquid crystal shutter optical systems. In addition, in the present invention, a back-facing method may be employed in which the electrostatic latent image carrier is exposed in an image-like manner from the back side.

[0114] -Developing process and developing means- The development step involves developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner to form a toner image. The developing means is a means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner to form a toner image. The development step can be suitably carried out by the development means.

[0115] The toner image can be formed, for example, by developing the electrostatic latent image using the toner. The developing means preferably includes, for example, a developer that contains the toner and can apply the toner to the electrostatic latent image by contact or non-contact, and more preferably a developer equipped with a toner container. The developer may be a single-color developer or a multi-color developer. For example, a suitable developer may have an agitator that frictionally agitates and charges the toner, and a rotatable magnetic roller.

[0116] -Transfer process and transfer means- The transfer step is a step of transferring the toner image formed on the electrostatic latent image carrier to the surface of the recording medium. The transfer means is a means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium. The transfer process can be suitably carried out by the transfer means.

[0117] The transfer step is preferably a configuration in which an intermediate transfer body is used to first transfer a toner image onto the intermediate transfer body, and then the toner image is secondarily transferred onto the recording medium. More preferably, the configuration includes a first transfer step in which two or more toners, preferably full-color toners, are used to transfer a toner image onto the intermediate transfer body to form a composite transfer image, and a second transfer step in which the composite transfer image is transferred onto the recording medium. 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 (photoreceptor) toward the recording medium. There may be one or more transfer means. Examples of the transfer device include a corona discharge transfer device, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

[0118] There are no particular restrictions on the recording medium, and it can be appropriately selected from known recording media (recording paper).

[0119] - Fixing process and fixing means - The fixing process is a process of fixing the toner image transferred to the surface of the recording medium. The fixing means is a means for fixing the toner image transferred to the surface of the recording medium. The fixing process can be suitably carried out by the fixing means. The fixing process may be performed each time a developer of each color is transferred to the recording medium, or it may be performed simultaneously with all the developer of each color stacked together. There are no particular restrictions on the fixing device used as the fixing means, and it can be appropriately selected according to the purpose, but known heating and pressing means are preferred. Examples of such heating and pressing means 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.

[0120] -Static elimination process and means- The static discharge step is a step of applying a static discharge bias to the electrostatic latent image carrier to discharge static electricity. The static discharge means is a means of performing static discharge by applying a static discharge bias to the electrostatic latent image carrier. The static elimination process can be suitably carried out by the static elimination means. The static elimination means is not particularly limited as long as it can apply a static elimination bias to the electrostatic latent image carrier, and can be appropriately selected from known static eliminators, such as static elimination lamps.

[0121] -Cleaning process and cleaning methods- The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier. The cleaning means is a means for removing the toner remaining on the electrostatic latent image carrier. The cleaning process can be suitably carried out by the cleaning means.

[0122] The cleaning means is not particularly limited as long as it can remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners, such as magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

[0123] -Recycling process and recycling methods- The recycling process is a process of recycling the toner removed by the cleaning process to the developing means. The recycling means is a means for recycling the toner removed by the cleaning means to the developing means. There are no particular limitations on the recycling means, and known transport means can be used. The recycling process can be suitably carried out by the recycling means.

[0124] -Control process and control means- The control step is a step that controls each of the steps. The control means is a means for controlling each of the means. The control process can be suitably carried out by the control means. The control means are not particularly limited as long as they can control the movement of each of the means, and can be appropriately selected according to the purpose. Examples include devices such as sequencers and computers.

[0125] (Manufacturing methods for printed materials) The present invention provides a method for manufacturing printed materials by forming an image on a recording medium using an image forming apparatus that includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, a developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner to form a toner image, a transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The method may include other steps as needed. The printed material has an image formed on the recording medium using the toner of the present invention. Since each step in the method for manufacturing the printed material can be the same as that used for the image forming method, redundant explanations will be omitted.

[0126] An example of an electrophotographic developing apparatus according to the present invention is shown in Figure 2. In Figure 2, the symbols 101A are the drive roller, 101B are the driven roller, 102 is the photoreceptor belt, 103 is the charger, 104 is the laser writing unit, 105A to 105D are the developing units that contain yellow, magenta, cyan, and black toners, respectively, 106 is the paper feed cassette, 107 is the intermediate transfer belt, 107A is the drive shaft roller for driving the intermediate transfer belt, 107B is the driven shaft roller that supports the intermediate transfer belt, 108 is the cleaning device, 109 is the fuser roller, 109A is the pressure roller, 110 is the output tray, and 113 is the paper transfer roller.

[0127] In this color image forming apparatus, a flexible intermediate transfer belt 107 is used with respect to the transfer drum. The intermediate transfer belt 107 is stretched between a drive shaft roller 107A and a pair of driven shaft rollers 107B and is circulated in a clockwise direction, with the belt surface between the pair of driven shaft rollers 107B in contact with the photoreceptor belt 102 on the outer circumference of the drive roller 101A from a horizontal direction.

[0128] During normal color image output, the toner images of each color formed on the photoreceptor belt 102 are transferred to the intermediate transfer belt 107 each time they are formed, synthesizing the color toner images. These are then transferred collectively to the transfer paper transported from the paper feed cassette 106 by the paper transfer roller 113. After the transfer, the transfer paper is transported between the fuser roller 109 and the pressure roller 109A of the fuser unit, and after fixing by the fuser roller 109 and the pressure roller 109A, it is discharged into the output tray 110. When the 105A-105E developing units develop toner, the toner concentration of the developer contained in the developing unit decreases. This decrease in toner concentration is detected by a toner concentration sensor (not shown). When a decrease in toner concentration is detected, a toner replenishment device (not shown) connected to each developing unit activates to replenish toner and increase the toner concentration. At this time, the toner replenished may be a so-called trickle developing agent in which the carrier and toner are mixed, provided that the developing unit is equipped with a developer discharge mechanism.

[0129] In Figure 1, an image is formed by superimposing a toner image onto an intermediate transfer belt. However, the electrophotographic image forming apparatus of the present invention can also be used in a system that transfers directly from the transfer drum to the recording medium without using an intermediate transfer belt.

[0130] Figure 2 shows an example of a developing apparatus used in the present invention, and modifications described later also fall within the scope of the present invention. In Figure 2, the developing device 40, which is positioned opposite the photoreceptor 20, which is an electrostatic latent image carrier, mainly consists of a developing sleeve 41 as a developer carrier, a developer containment member 42, a doctor blade 43 as a regulating member, a support case 44, and the like. A toner hopper 45, which serves as a toner storage section for housing toner 21, is attached to a support case 44 having an opening on the photoreceptor 20 side. Adjacent to the toner hopper 45 is a developer storage section 46 that houses toner 21 and a developer consisting of a carrier 23, and a developer stirring mechanism 47 is provided to agitate the toner 21 and carrier 23 and impart a friction / peeling charge to the toner 21. Inside the toner hopper 45 are a toner agitator 48 and a toner supply mechanism 49, which are toner supply means rotated by a drive mechanism (not shown). The toner agitator 48 and the toner supply mechanism 49 send the toner 21 in the toner hopper 45 toward the developer storage section 46 while agitating it.

[0131] A developing sleeve 41 is disposed in the space between the photoreceptor 20 and the toner hopper 45. The developing sleeve 41, which is rotationally driven in the direction of the arrow in the figure by a driving means (not shown), has a magnet (not shown) inside it, which is disposed in a position constant relative to the developing device 40, to form a magnetic brush by the carrier 23, and serves as a magnetic field generating means. A doctor blade 43 is integrally attached to the side of the developer container 42 that is opposite to the side attached to the support case 44. In this example, the doctor blade 43 is positioned so as to maintain a certain gap between its tip and the outer surface of the developing sleeve 41. Using such apparatus without limitation, the image forming method of the present invention is carried out as follows. That is, with the above configuration, the toner 21 sent out from inside the toner hopper 45 by the toner agitator 48 and toner supply mechanism 49 is transported to the developer storage section 46, where it is agitated by the developer stirring mechanism 47 to impart the desired friction / peeling charge, and together with the carrier 23 as a developer, it is carried on the developing sleeve 41 to a position facing the outer surface of the photoreceptor 20, where only the toner 21 electrostatically couples with the electrostatic latent image formed on the photoreceptor 20, thereby forming a toner image on the photoreceptor 20.

[0132] Figure 3 shows an example of an image forming apparatus having the developing apparatus shown in Figure 2. A charging member 32, an image exposure system 33, a developing apparatus 40, a transfer apparatus 50, a cleaning apparatus 60, and a static elimination lamp 70 are arranged around a drum-shaped photoreceptor 20. In this example, the surface of the charging member 32 is in a non-contact state with a gap of approximately 0.2 mm from the surface of the photoreceptor 20. When the photoreceptor 20 is charged by the charging member 32, the photoreceptor 20 is charged by an electric field in which an AC component is superimposed on a DC component by a voltage application means (not shown) applied to the charging member 32, thereby reducing uneven charging and being effective. The image forming method, including the developing method, is performed in the following operation.

[0133] The image formation process can be described using a negative-positive process. The photoreceptor 20, typified by an OPC photoreceptor having an organic photoconductive layer, is discharged by an elimination lamp 70, uniformly negatively charged by charging members 32 such as a charging charger and charging roller, and latent image formation is performed by laser light irradiated from an image exposure system 33 such as a laser optical system (in this example, the absolute value of the potential of the exposed area is lower than the absolute value of the potential of the unexposed area).

[0134] Laser light is emitted from a semiconductor laser and scans the surface of the photoreceptor 20 in the direction of the rotation axis of the photoreceptor 20 using a high-speed rotating polygonal prism or the like. The latent image thus formed is developed by a developer consisting of a mixture of toner and carrier supplied onto a developer sleeve 41, which is a developer carrier in the developing device 40, and a toner image is formed. During the development of the latent image, a development bias of a certain appropriate magnitude, or a DC voltage superimposed on an AC voltage, is applied to the developing sleeve 41 from a voltage application mechanism (not shown) between the exposed and unexposed parts of the photoreceptor 20.

[0135] Meanwhile, the transfer medium (e.g., paper) 80 is fed from a paper feeding mechanism (not shown) and, synchronized with the leading edge of the image by a pair of upper and lower registration rollers (not shown), is fed between the photoreceptor 20 and the transfer device 50 to transfer the toner image. At this time, it is preferable that a potential with the opposite polarity to the toner charge is applied to the transfer device 50 as a transfer bias. After that, the transfer medium 80 is separated from the photoreceptor 20 and the transferred image is obtained. Furthermore, any toner remaining on the photoreceptor 20 is collected in the toner recovery chamber 62 within the cleaning device 60 by the cleaning blade 61, which acts as a cleaning component.

[0136] The collected toner may be transported to the developer storage unit 46 and / or toner hopper 45 by a toner recycling means (not shown) and reused. The image forming apparatus may be an apparatus that arranges multiple developing apparatuses as described above, sequentially transfers toner images onto a transfer medium, then sends them to a fixing mechanism to fix the toner by heat or the like, or it may be an apparatus that first transfers multiple toner images onto an intermediate transfer medium, then transfers them all at once to the transfer medium and fixes them in the same way.

[0137] Figure 4 shows another example of an image forming apparatus used in the present invention. The photoreceptor 20 has at least a photosensitive layer provided on a conductive support and is driven by drive rollers 24a and 24b, and repeatedly undergoes charging by a charging member 32, image exposure by an image exposure system 33, development by a developing device 40, transfer using a transfer device 50, pre-cleaning exposure by a pre-cleaning exposure light source 26, cleaning by a brush-shaped cleaning means 64 and a cleaning blade 61, and static discharge by a static discharge lamp 70. In Figure 4, the photoreceptor 20 (of course, in this case the support is translucent) is subjected to pre-cleaning exposure from the support side.

[0138] The image forming apparatus of the present invention comprises at least an electrostatic latent image carrier, an electrostatic latent image forming means, and a developing means, and further comprises other means as necessary. The image forming method according to the present invention includes at least an electrostatic latent image formation step and a development step, and further includes other steps as necessary.

[0139] 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, and the other steps can be suitably carried out by the other means.

[0140] The image forming apparatus of the present invention more preferably includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, a developing means equipped with toner for developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a toner image, a transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium.

[0141] Furthermore, the image forming method of the present invention more preferably includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a toner image, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0142] Next, one embodiment of the image forming apparatus of the present invention will be described with reference to Figure 5. The color image forming apparatus 100A shown in Figure 5 comprises a photoreceptor drum 10 (hereinafter sometimes referred to as "photoreceptor 10") as the electrostatic latent image carrier, a charging roller 20 as the charging means, an exposure device 30 as the exposure means, a developer 40 as the developing means, an intermediate transfer body 50, a cleaning device 60 as the cleaning means having a cleaning blade, and a static elimination lamp 70 as the static elimination means.

[0143] The intermediate transfer body 50 is an endless belt and is designed to be movable in the direction of the arrow by three rollers 51 positioned inside it and tensioning it. Part of the three rollers 51 also function as transfer bias rollers capable of applying a predetermined transfer bias (primary transfer bias) to the intermediate transfer body 50. A cleaning device 90 having a cleaning blade is positioned near the intermediate transfer body 50. Also positioned near the intermediate transfer body 50, facing the intermediate transfer body 50, is a transfer roller 80, which is a transfer means capable of applying a transfer bias for transferring a developed image (toner image) to a transfer paper 95, which is a recording medium (secondary transfer). Around the intermediate transfer body 50, a corona charger 58 for imparting an electric charge to the toner image on the intermediate transfer body 50 is positioned between the contact area between the photoreceptor 10 and the intermediate transfer body 50 and the contact area between the intermediate transfer body 50 and the transfer paper 95 in the rotational direction of the intermediate transfer body 50.

[0144] The developing unit 40 consists of a developing belt 41 as a developer carrier, and a black (Bk) developing unit 45K, a yellow (Y) developing unit 45Y, a magenta (M) developing unit 45M, a cyan (C) developing unit 45C, and a metallic (G) developing unit 45G, all of which are arranged around the developing belt 41. The black developing unit 45K includes a developer storage section 42K, a developer supply roller 43K, and a developing roller 44K. The yellow developing unit 45Y includes a developer storage section 42Y, a developer supply roller 43Y, and a developing roller 44Y. The magenta developing unit 45M includes a developer storage section 42M, a developer supply roller 43M, and a developing roller 44M. The cyan developing unit 45C includes a developer storage section 42C, a developer supply roller 43C, and a developing roller 44C. The metallic developing unit 45G comprises a developer storage section 42G, a developer supply roller 43G, and a developing roller 44G. The developing belt 41 is an endless belt, rotatably stretched over multiple belt rollers, with a portion of it in contact with the electrostatic latent image carrier 10.

[0145] The following describes specific aspects of the image formation method. Image data sent to the Image Processing Unit (hereinafter referred to as "IPU") generates image signals for each of the five colors: Y (yellow), M (magenta), C (cyan), K (black), and G (metallic). Next, the image processing unit transmits the Y, M, C, K, and G image signals to the writing unit. The writing unit modulates and scans five laser beams for Y, M, C, K, and G, charges the photoreceptor drums with the charging unit, and then sequentially creates electrostatic latent images on each photoreceptor drum. Here, for example, the first photoreceptor drum corresponds to K, the second to Y, the third to M, the fourth to C, and the fifth to G (metallic).

[0146] Next, a developing unit, acting as a developing and adhesion means, creates toner images of each color on the photoreceptor drum. Furthermore, the transfer paper fed by the paper feeding unit is transported along a transfer belt, and the toner images on the photoreceptor drum are sequentially transferred onto the transfer paper by a transfer charger. After this transfer process is complete, the transfer paper is transported to a fixing unit, where the transferred toner image is fixed onto the transfer paper. After the transfer process is complete, any toner remaining on the photoreceptor drum is removed by the cleaning unit. [Examples]

[0147] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited in any way to these examples. In the following examples and comparative examples, unless otherwise specified, "parts" refers to "parts by mass".

[0148] (Example 1) The present invention will be described in more detail below based on examples. In the following descriptions, unless otherwise specified, "parts" refers to "parts by mass," and "%" refers to "percentage by mass." It is easy for those skilled in the art to make appropriate changes and modifications to the embodiments of the present invention shown below to create other embodiments, and these changes and modifications are included in the present invention. The following description is an example of a preferred embodiment of the present invention and does not limit the present invention.

[0149] <Preparation of amorphous polyester resin> In a reaction vessel equipped with a condenser, a stirrer, and nitrogen inlet, the monomer species shown in Table 1 below and tetrabutoxytitanate as a condensation catalyst were added and reacted at 230°C for 6 hours under a nitrogen stream, while distilling off the water produced. Next, the reaction was carried out under reduced pressure of 5 mmHg to 20 mmHg for 1 hour to obtain an amorphous polyester resin. In Table 1, the "25 mol%" indicated for bisphenol A(2,2) propylene oxide represents the proportion of the alcohol component when the acid component and alcohol component are both 50 mol%.

[0150] [Table 1]

[0151] <Preparation of crystalline polyester resin> A 5L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with fumaric acid and 1,6-hexanediol in an OH / COOH ratio of 0.9. This mixture was then reacted with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours, followed by a reaction at 200°C for 3 hours. Finally, the mixture was reacted at a pressure of 8.3 kPa for 2 hours to obtain a crystalline polyester resin.

[0152] <Preparation of toner matrix particles> The following materials were pre-mixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Machinery Co., Ltd.), and then melted and kneaded at 120°C in a twin-shaft kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). • Amorphous polyester resin: 88.5 parts Crystalline polyester resin: 4.5 parts • Styrene-α-methylstyrene copolymer: 8.0 parts (SA140, manufactured by Kraton, Tg value 87°C) • Hydrocarbon wax (Fischer-Tropsch wax FNP-0090, manufactured by Nippon Seiro Co., Ltd.): 4.0 parts • Carbon black (#44, manufactured by Mitsubishi Chemical): 13.0 parts

[0153] [Conditions for pre-mixing] The pre-mixing conditions were as follows: [1400rpm 1min on 2min off] x 5 times The resulting mixture was rolled to a thickness of 4.0 mm using rollers, cooled to room temperature in a belt cooler, and then coarsely ground in a hammer mill to an average particle size of 200 μm to 300 μm. Next, the coarsely ground mixture was finely ground using a supersonic jet pulverizer, LabJet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an airflow classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain [toner matrix particles 1].

[0154] Regarding the glass transition temperature (Tg) of the aromatic petroleum resin styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton), although the catalog value is 87°C, there is a variation of approximately ±5°C depending on the production lot. Therefore, the Tg value was measured in advance using the following measurement method and was used. The same applies to the following examples and comparative examples.

[0155] <Method for measuring the glass transition temperature (Tg) of styrene-α-methylstyrene copolymers> Approximately 5.0 mg of the target sample, styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton), was placed in an aluminum sample container. The sample container was then placed on a holder unit and set in an electric furnace. Next, under a nitrogen atmosphere, the temperature was increased from -80°C to 150°C at a heating rate of 10°C / min. The glass transition temperature (Tg) of the styrene-α-methylstyrene copolymer was determined from the obtained DSC curve using an analysis program in a differential scanning calorimeter. The determined glass transition temperature (Tg) of the styrene-α-methylstyrene copolymer was 81°C.

[0156] <Preparation of toner developer> To 100 parts by mass of the obtained toner matrix particles, 1 part by mass of metal oxide fine particles (HDK-2000, Clariant Co., Ltd.) was added as an external additive and mixed with a Henschel mixer to produce an externally additive-treated toner. The obtained externally additive-treated toner (5% by mass) and the coated ferrite carrier (95% by mass) were uniformly mixed at 48 rpm for 5 minutes using a turbler mixer (manufactured by Willy e Bakkofen (WAB)) to prepare [toner developer 1].

[0157] <Average circularity> Using a Flow Particle Image Analyzer (FPIA-3000, manufactured by Sysmex Corporation), 0.1 to 0.5 ml of alkylbenzene sulfonate was added as a dispersant to 100 to 150 ml of water from which impurities had been removed from a container. Then, approximately 0.1 g to 0.5 g of the sample to be measured was added. The suspension containing the dispersed sample was subjected to dispersion treatment in an ultrasonic disperser for approximately 1 to 3 minutes. The dispersion concentration was set to 3000 particles / μl to 10000 particles / μl, and the shape of the toner was measured using the above apparatus. The results are shown in Table 4.

[0158] <Method for measuring the aspect ratio of the release agent domain> By observing the particle cross-section of [toner matrix particle 1] using a transmission electron microscope, the major and minor axes of the release agent domains present within [toner matrix particle 1] were measured, and the aspect ratio was determined. First, the particles of [Toner Matrix Particle 1] were sufficiently dispersed in a room-temperature curing epoxy resin. Then, the toner particles were embedded in the epoxy resin, and the epoxy resin was allowed to fully cure. Subsequently, a cross-sectional image of the particles of [Toner Matrix Particle 1] was prepared using an ultramicrotome (ultrasonic), and staining was performed using ruthenium tetroxide and osmium tetroxide in combination as needed. This was observed using a scanning transmission electron microscope (STEM) (LEM-2000 (Topcon), JEM-2000FX (JEOL), etc.), and images were taken at a magnification of 2000x to obtain a cross-sectional image of the particles of [Toner Matrix Particle 1]. From the obtained cross-sectional image of the toner particles of [Toner Matrix Particle 1], the major and minor axes of the release agent domains present in the cross-sectional image of the toner particles of [Toner Matrix Particle 1] were determined. The above calculations were performed using the tissue analysis method of the image analysis software "A-zo-kun" (registered trademark, manufactured by Asahi Kasei Engineering Co., Ltd.). Specifically, 100 toner cross-sectional images were selected, and the analysis conditions were set to "3" for the number of tissues and "manual" for the multi-level conversion method. The release agent domain region was separated and recognized from the total area of ​​the toner cross-section, and the major and minor axes of the release agent domain were calculated from the region obtained through separation and recognition. The aspect ratio of the release agent domain was calculated from the major and minor axes of the obtained release agent domains based on the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1)

[0159] <Measurement results> Table 3 shows the average number of release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less in 100 toner particle cross-sections, and the average number of release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.5 or less in 100 toner particle cross-sections, obtained from the analysis.

[0160] [Low temperature fixation] The obtained [toner developer 1] was placed in a Ricoh IM C5510 copier and an image was printed. Toner deposition amount: 0.4 mg / cm² 2The solid image was formed on a recording medium, paper (Ricoh Co., Ltd., Type 6200), through exposure, development, and transfer processes. The fixing linear velocity was set to 256 mm / second. Fixing temperatures were sequentially output in 2°C increments, and the lower limit temperature at which cold offset did not occur was measured. Low-temperature fixing performance was evaluated based on the evaluation criteria below. The lower limit temperature at which cold offset does not occur is the fixing limit temperature. The results are shown in Table 4. Grades "A" to "C" were judged to be sufficient for practical use.

[0161] -Evaluation Criteria for Low-Temperature Fixation- A: Below 120℃ B: 120℃ or higher but less than 125℃ C: 125℃ or higher, less than 130℃ D: 130℃ or more

[0162] [Hot offset resistance] The obtained [toner developer 1] was put into the storage unit of a copier (RICOH MPC 6003, manufactured by Ricoh Co., Ltd.), and the amount of toner deposited was 0.4 mg / cm². 2 A solid image was formed on the recording medium, paper (Type 6200, manufactured by Ricoh Co., Ltd.), in this manner. The fixing linear velocity was set to 256 mm / sec, the NIP width of the fixing device to 11 mm, and the fixing temperature was sequentially output in 5°C increments. The upper limit temperature at which hot offset does not occur was measured, and the hot offset resistance was evaluated based on the evaluation criteria below. The upper limit temperature at which hot offset does not occur is the fixing limit temperature. The results are shown in Table 4. Grades "A" to "C" were judged to be sufficient for practical use. [Evaluation Criteria] A: The maximum fixing temperature is 200°C or higher. B: Fixing upper limit temperature is 190°C or higher but less than 200°C C: Fixing upper limit temperature is 180°C or higher but less than 190°C D: Fixing limit temperature is less than 180°C

[0163] [Filming resistance (HH environment)] The obtained [toner developer 1] was placed in a Ricoh IM 9000 copier and run 200,000 times in a high-temperature, high-humidity environment (30°C, 90%) with an image area ratio of 1.0%. After that, the filming state on the photoreceptor, which is the electrostatic latent image carrier, was visually observed, and the filming was evaluated based on the evaluation criteria below. The results are shown in Table 4. Grades "A" to "C" were judged to be practically sufficient. -Evaluation Criteria for Filming- A: No toner residue was found on the photoconductor. B: Tiny toner deposits can be seen on a portion of the photoreceptor, but they do not affect the image. C: Numerous toner deposits are visible on the photoconductor, but this does not affect the image. D: A large amount of toner residue was observed on the photoconductor, resulting in image abnormalities.

[0164] [Filming Resistant (MM Environment)] The obtained [toner developer 1] was placed in a Ricoh IM C9000 copier and run 200,000 copies at an image area ratio of 1.0% in a medium temperature and humidity environment (23°C, 50%). After that, the filming state on the photoreceptor, which is the electrostatic latent image carrier, was visually observed, and the filming was evaluated based on the evaluation criteria below. The results are shown in Table 4. Grades "A" to "C" were judged to be practically sufficient. -Evaluation Criteria for Filming- A: No toner residue was found on the photoconductor. B: Tiny toner deposits can be seen on a portion of the photoreceptor, but they do not affect the image. C: Numerous toner deposits are visible on the photoconductor, but this does not affect the image. D: A large amount of toner residue was observed on the photoconductor, resulting in image abnormalities.

[0165] (Example 2) In Example 1, the temperature of the twin-screw kneader was changed from 120°C to 130°C, the pre-mixing conditions were changed to [1400 rpm, 1 min on, 2 min off] x 4 times, and the amount of styrene-α-methylstyrene copolymer (SA140, Kraton) was changed from 8.0 parts to 7.0 parts. Otherwise, [toner matrix particles 2] and [toner developer 2] were prepared in the same manner as in Example 1, and measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Tables 3 and 4.

[0166] (Example 3) In Example 1, the temperature of the twin-screw kneader was changed from 120°C to 105°C, the pre-mixing conditions were changed to [1500 rpm, 1 min on, 2 min off] x 6 times, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 9.5 parts. Otherwise, the [toner matrix particles 3] and [toner developer 3] were prepared in the same manner as in Example 1, and measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Tables 3 and 4.

[0167] (Example 4) In Example 1, the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) in the pre-mixing step was changed from 4.0 parts to 2.5 parts. Except for this change, the toner matrix particles 4 and toner developer 4 were prepared in the same manner as in Example 1, and measurements and evaluations were performed in the same manner as in Example 1. The results are shown in Tables 3 and 4.

[0168] (Example 5) In Example 1, the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) in the pre-mixing step was changed from 4.0 parts to 5.5 parts. Except for this change, the toner matrix particles 5 and toner developer 5 were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0169] (Example 6) In Example 1, the toner matrix particles 6 and toner developer 6 were prepared in the same manner as in Example 1, except that the pre-mixing conditions were changed to [1200 rpm, 1 min on, 2 min off] x 4 times. The same measurements and evaluations were then performed. The results are shown in Tables 3 and 4.

[0170] (Example 7) In Example 1, the toner matrix particles 7 and toner developer 7 were prepared in the same manner as in Example 1, except that the pre-mixing conditions were changed to [1000 rpm, 1 min on, 2 min off] x 3 times. The same measurements and evaluations were then performed. The results are shown in Tables 3 and 4.

[0171] (Example 8) In Example 1, the wax type was changed from hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) to rice brown wax (300VITA, manufactured by Clariant Co., Ltd.). Except for this change, the toner matrix particles 8 and toner developer 8 were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0172] (Comparative Example 1) In Example 1, the temperature of the twin-screw kneader was changed from 120°C to 140°C, the pre-mixing conditions were changed to [1400 rpm, 1 min on, 2 min off] x 6 times, and the amount of styrene-α-methylstyrene copolymer (SA140, Kraton) was changed from 8.0 parts to 12.0 parts. Otherwise, the [toner matrix particles 9] and [toner developer 9] were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0173] (Comparative Example 2) In Example 1, the temperature of the twin-screw kneader was changed from 120°C to 100°C, the pre-mixing conditions were changed to [1400 rpm, 1 min on, 2 min off] x 4 times, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 4.0 parts. Otherwise, the [toner matrix particles 10] and [toner developer 10] were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0174] (Comparative Example 3) In Example 1, the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) in the premixing step was changed from 4.0 parts to 2.0 parts. Except for this change, the toner matrix particles 11 and toner developer 11 were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0175] (Comparative Example 4) In Example 1, the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) in the premixing step was changed from 4.0 parts to 6.0 parts. Except for this change, the toner matrix particles 12 and toner developer 12 were prepared in the same manner as in Example 1, and the same measurements and evaluations were performed. The results are shown in Tables 3 and 4.

[0176] Table 2 below shows the formulations and preliminary mixing conditions of the toner matrix particles in each example and comparative example.

[0177] [Table 2]

[0178] [Table 3]

[0179] [Table 4]

[0180] As shown above, the toners in Examples 1 to 8 satisfy the following requirements specified in the present invention and therefore have practically sufficient characteristics. On the other hand, the toners in Comparative Examples 1 to 4 do not satisfy the following requirements and therefore do not have practically sufficient characteristics. (Requirements): On average, there are 2 to 8 release agent domains per toner particle, each having a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1)

[0181] Examples of embodiments of the present invention are as follows. (1) A toner comprising toner particles containing polyester resin, aromatic petroleum resin, and a mold release agent, A toner characterized in that, when the cross-section of the toner particles is observed with a scanning electron microscope, the domains of the release agent satisfy the following requirements. (Requirements) Each toner particle contains, on average, 2 to 8 release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1) (2) The toner according to (1) above, wherein when the cross-section of the toner particles is observed with a scanning electron microscope, there are an average of 2 to 5 release agent domains per toner particle, each having a major axis of 400 nm or more and an aspect ratio of 0.5 or less. (3) The toner according to (1) above, wherein the content of the aromatic petroleum resin is 7 parts by mass or more and 9.5 parts by mass or less per 100 parts by mass of the total amount of the polyester resin, the release agent and the aromatic petroleum resin. (4) The toner according to (1) above, which contains a hydrocarbon wax as the mold release agent. (5) The toner according to (1) above, wherein the glass transition temperature of the aromatic petroleum resin is 70°C or higher and 90°C or lower. (6) The toner described in (1) above, wherein the average circularity of the toner is 0.93 or more and 0.96 or less. (7) A developer characterized by comprising the toner described in any one of the above items (1) to (6), and a carrier. (8) A toner storage unit characterized by storing the toner described in any one of the above items (1) to (6). (9) Electrostatic latent image carrier and An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, Develop the electrostatic latent image formed on the electrostatic latent image carrier using the toner according to any one of the above (1) to (6), and form a toner image on the electrostatic latent image carrier; a developing means; Transfer the toner image formed on the electrostatic latent image carrier to the surface of a recording medium; a transfer means; Fix the toner image transferred to the surface of the recording medium; a fixing means, and an image forming apparatus characterized by including the same. (10) An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier; A developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner according to any one of the above (1) to (6), and forming a toner image on the electrostatic latent image carrier; A transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium; A fixing step of fixing the toner image transferred to the surface of the recording medium, and an image forming method characterized by including the same. (11) A method for manufacturing a printed matter, characterized by forming an image on a recording medium using the image forming apparatus according to the above (9) to obtain a printed matter. (12) A method for manufacturing a toner for manufacturing the toner according to any one of the above (1) to (6), Including a step of manufacturing toner base particles containing a polyester resin and an aromatic petroleum resin, The addition amount of the aromatic petroleum resin in the step of manufacturing the toner base particles is 7 parts by mass or more and 9.5 parts by mass or less when the total amount of the toner base particles is 100 parts by mass, and a method for manufacturing a toner characterized by the same. [[ID=***]]

Explanation of Signs

[0182] 10 Electrostatic latent image carrier (photoconductor drum) 14 Roller 15 Roller 16 Roller 17 Cleaning device 18 Image forming means 20 Charging roller [[ID=4***]] 21 Exposure device 22 Secondary transfer device 23 Rollers 24 Secondary Transfer Belt 25 Fixing Device 26 Fixing Belt 27 Pressing Roller 28 Sheet Reversing Device 29 Corona Charger 32 Contact Glass 33 First Traveling Body 34 Second Traveling Body 35 Imaging Lens 36 Reading Sensor 40 Developing Device 41 Developing Belt 42K Developer Container 42Y Developer Container 42M Developer Container 42C Developer Container 43K Developer Supply Roller 43Y Developer Supply Roller 43M Developer Supply Roller 43C Developer Supply Roller 44K Developing Roller 44Y Developing Roller 44M Developing Roller 44C Developing Roller 45K Black Developing Unit 45Y Yellow Developing Unit 45M Magenta Developing Unit 45C Cyan Developing Unit 49 Resist Roller 50 Intermediate Transfer Belt 51 Roller 52 Separation Roller 53 Manual Feed Path 54 Manual Tray 55 Switching Claw 56 Discharge Roller 57 Discharge Tray 58 Corona Charging Device 60 Cleaning Device 61 Developing Device 62 Transfer Roller 63 Photoconductor Cleaning Device 64-removing power lamp 70-removing power lamp 80-transfer roller 90-cleaning device 95-transfer paper 100A-image forming apparatus 100B-image forming apparatus 100C-image forming apparatus 120-image forming unit 130-original document table 142-paper feed roller 143-paper bank 144-paper feed cassette 145-separation roller 146-paper feed path 147-transfer roller 148-paper feed path 150-copying apparatus main body -paper feed table 300-scanner 400-automatic document feeder (ADF) 500-process cartridge

Prior Art Documents

Patent Documents

[0183]

Patent Document 1

Patent Document 2

Patent Document 3

Claims

1. A toner containing toner particles that include a polyester resin, an aromatic petroleum resin, and a mold release agent, A toner characterized in that, when the cross-section of the toner particles is observed with a scanning electron microscope, the domains of the release agent satisfy the following requirements. (Requirements) Each toner particle contains, on average, two to eight release agent domains with a major axis of 400 nm or more and an aspect ratio of 0.7 or less calculated by the following formula (1). Aspect ratio = (Short diameter of release agent domain) / (Long diameter of release agent domain) Equation (1)

2. The toner according to claim 1, wherein when the cross-section of the toner particles is observed with a scanning electron microscope, there are, on average, two to five release agent domains per toner particle, each having a major axis of 400 nm or more and an aspect ratio of 0.5 or less.

3. The toner according to claim 1, wherein the content of the aromatic petroleum resin is 7 parts by mass or more and 9.5 parts by mass or less, based on a total amount of 100 parts by mass of the polyester resin, the mold release agent, and the aromatic petroleum resin.

4. The toner according to claim 1, further comprising a hydrocarbon wax as the mold release agent.

5. The toner according to claim 1, wherein the glass transition temperature of the aromatic petroleum resin is 70°C or higher and 90°C or lower.

6. The toner according to claim 1, wherein the average circularity of the toner is 0.93 or more and 0.96 or less.

7. A developer comprising the toner described in any one of claims 1 to 6 and a carrier.

8. A toner storage unit characterized by storing the toner described in any one of claims 1 to 6.

9. Electrostatic latent image carrier, An electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, A developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner described in any one of claims 1 to 6, thereby forming a toner image on the electrostatic latent image carrier, A transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, An image forming apparatus characterized by comprising fixing means for fixing a toner image transferred to the surface of the recording medium.

10. An electrostatic latent image formation step in which an electrostatic latent image is formed on an electrostatic latent image carrier, A developing step comprising developing the electrostatic latent image formed on the electrostatic latent image carrier using the toner described in any one of claims 1 to 6, thereby forming a toner image on the electrostatic latent image carrier, A transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, An image forming method characterized by comprising a fixing step of fixing a toner image transferred to the surface of the recording medium.

11. A method for manufacturing a printed material, characterized by forming an image on a recording medium using the image forming apparatus described in claim 9 to obtain a printed material.

12. A method for manufacturing toner according to any one of claims 1 to 6, The process includes manufacturing steps for toner matrix particles containing polyester resin and aromatic petroleum resin. A method for manufacturing toner, characterized in that the amount of aromatic petroleum resin added in the manufacturing process of the toner matrix particles is 7 parts by mass or more and 9.5 parts by mass or less, when the total amount of the toner matrix particles is 100 parts by mass.

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