Toner, developer, toner storage unit, image forming apparatus, image forming method, print manufacturing method, and toner manufacturing method

Abstract

To provide a toner that is excellent in low temperature fixability and can achieve both prevention of filming in a high temperature and high humidity environment and releasability during fixing.SOLUTION: A toner for electrostatic charge image development includes toner particles containing polyester resin, a mold release agent, and aromatic petroleum resin. When a cross section of the toner particle is observed with a scanning electron microscope, a domain of the mold release agent and a domain of the aromatic petroleum resin that are observed satisfy the following condition 1 and condition 2. (Condition 1) the average value of values of the ratio of the area of the domains of the mold release agent (Sw) to the area of the domains of the aromatic petroleum resin (Sa) (Sw / Sa) in 100 toner particles satisfies the following relational expression (1). (1) 0.05≤Sw / Sa<0.5. (Condition 2) the average value of shape factors SF2 of the domains of the mold release agent in 100 toner particles satisfies the following relational expression (2). (2) 150≤SF2≤300.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner, a developer, a toner storage unit, an image forming apparatus, an image forming method, a method for producing a printed matter, and a method for producing a toner. [Background technology]

[0002] Conventionally, in electrophotographic devices, electrostatic recording devices, and the like, electric latent images or magnetic latent images are visualized by electrostatic latent image developing toner (also referred to as "toner" in the present invention). For example, in electrophotography, an electrostatic latent image is formed on a photoreceptor, and then the electrostatic latent image is developed with 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, there has been a demand for low-temperature fixing of toners in order to save energy by reducing the energy required for fixing. Furthermore, due to the demand for faster speeds and higher image quality of image forming apparatuses, coupled with the diversification of the purposes for which image forming apparatuses are used, there has been an increasing demand for low-temperature fixing of toners. As a method for low-temperature fixing of toners, a technique of using a non-crystalline polyester resin and a crystalline polyester resin in combination is known.

[0004] For example, a pulverized toner has been disclosed that aims to provide a toner with excellent grindability during production and excellent fixing stability, and is produced by pulverizing and classifying a composition in which a styrene resin with a mass average molecular weight (Mw) of more than 3,000 is internally added to a mixture of a binder resin and a colorant (see, for example, Patent Document 1). Also, a pulverized toner has been disclosed that aims to provide a pulverized toner that can achieve both low-temperature fixing properties and heat-resistant storage stability, in which the maximum peak ratio of the polyester resin to the styrene resin measured by FT-IR has been specified (see, for example, Patent Document 2). Also, a toner has been disclosed that aims to provide a toner that can achieve both good release properties of fixed images and suppression of image density reduction during continuous printing in a low-temperature, low-humidity environment, 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 has been specified (see, for example, Patent Document 3). Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional toners, including those described in Patent Documents 1 to 3, have been known to have problems such as image defects caused by filming, which occurs when 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, high-humidity environments, and image defects become even more pronounced when the printing area is small. On the other hand, when the amount of wax used is reduced, release properties during fixing become an issue. Achieving both filming suppression and release properties during fixing in such high-temperature, high-humidity environments has been an issue.

[0006] An object of the present invention is to provide a toner that has excellent low-temperature fixability, and is capable of suppressing filming in a high-temperature, high-humidity environment while also providing good releasability during fixation. [Means for solving the problem]

[0007] The toner of the present invention that solves the above problems is as described below. A toner comprising toner particles containing a polyester resin, a release agent, and an aromatic petroleum resin, A toner for developing electrostatic images, characterized in that, when a cross section of the toner particle is observed with a scanning electron microscope, the domains of the release agent and the domains of the aromatic petroleum resin observed satisfy the following conditions 1 and 2: (Condition 1) For 100 toner particles, the average value of the ratio (Sw / Sa) of the domain area (Sw) of the release agent to the domain area (Sa) of the aromatic petroleum resin satisfies the following relational expression (1). 0.05≦Sw / Sa<0.5 (1) (Condition 2) The average value of the shape factor SF2 of the domain of the release agent for 100 toner particles satisfies the following relational expression (2). 150≦SF2≦300 (2) [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a toner that has excellent low-temperature fixing properties, and is capable of suppressing filming in a high-temperature, high-humidity environment while also providing good releasability during fixing. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic explanatory diagram illustrating an embodiment of an image forming apparatus of the present invention. [Figure 2] FIG. 10 is a schematic explanatory diagram for explaining another embodiment of the image forming apparatus of the present invention. [Figure 3] FIG. 10 is a schematic explanatory diagram for explaining still another embodiment of the image forming apparatus of the present invention. [Figure 4] FIG. 2 is a schematic explanatory diagram for explaining an image forming unit. [Figure 5] 1 is a schematic diagram illustrating an example of a process cartridge according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The toner of the present invention is a toner comprising toner particles containing a polyester resin, a release agent, and an aromatic petroleum resin, A toner for developing electrostatic images, characterized in that, when a cross section of the toner particle is observed with a scanning electron microscope, the domains of the release agent and the domains of the aromatic petroleum resin observed satisfy the following conditions 1 and 2: (Condition 1) For 100 toner particles, the average value of the ratio (Sw / Sa) of the domain area (Sw) of the release agent to the domain area (Sa) of the aromatic petroleum resin satisfies the following relational expression (1). 0.05≦Sw / Sa<0.5 (1) (Condition 2) The average value of the shape factor SF2 of the domain of the release agent for 100 toner particles satisfies the following relational expression (2). 150≦SF2≦300 (2)

[0011] The present invention will be described in detail below.

[0012] (toner) The toner of the present invention comprises toner particles containing a polyester resin, a release agent, and an aromatic petroleum resin, and may contain a colorant, an external additive, and other components as required. The toner of the present invention is a toner for developing electrostatic images, characterized in that when a cross section of the toner particle is observed with a scanning electron microscope, the domains of the release agent and the domains of the aromatic petroleum resin observed satisfy the following conditions 1 and 2: (Condition 1) For 100 toner particles, the average value of the ratio (Sw / Sa) of the domain area (Sw) of the release agent to the domain area (Sa) of the aromatic petroleum resin satisfies the following relational expression (1). 0.05≦Sw / Sa<0.5 (1) (Condition 2) The average value of the shape factor SF2 of the domain of the release agent for 100 toner particles satisfies the following relational expression (2).

[0013] In the present invention, when the cross section of a toner particle is observed, it is important that the average value of the ratio (Sw / Sa) of the domain area of ​​the release agent (Sw) to the domain area (Sa) of the aromatic petroleum resin for 100 toner particles satisfies the following relational expression (1): 0.05≦Sw / Sa<0.5 (1) The Sw / Sa ratio represents the area ratio of the release agent to the aromatic petroleum resin present within the toner particle. When the Sw / Sa ratio is 0.5 or greater, the amount of release agent present is greater than that of the aromatic petroleum resin, making it more likely to remain on the toner surface and adhere to the photoreceptor during actual image formation, causing problems like filming. Furthermore, when the Sw / Sa ratio is less than 0.05, the amount of release agent present is so small compared to the aromatic petroleum resin that less of the release agent seeps onto the toner surface during high-temperature fixing, resulting in offset images.

[0014] It is also important that the average value of the roughness (SF2) of the domains of the release agent satisfies the following relational expression (2). 150≦SF2≦300 (2) The SF2 of the domain of a release agent is a value that is affected by the substances surrounding the release agent. When the solubility parameter and other properties of the substances surrounding the release agent are similar to those of the release agent, the release agent is partially compatible with the surrounding substances, resulting in unevenness at the release agent interface and a tendency for the SF2 value to increase. On the other hand, when the solubility parameter and other properties of the substances surrounding the release agent are different from those of the release agent, the release agent is less compatible with the surrounding substances, resulting in less unevenness at the release agent interface and a tendency for the SF2 value to decrease. When the solubility parameter and other properties of the substances surrounding the release agent are similar to those of the release agent, the release agent dispersed by shear during kneading is less likely to re-aggregate upon cooling, making it easier for the release agent to maintain its dispersed state within the toner particles during kneading.

[0015] If the average SF2 value is less than 150, the release agent dispersed during kneading tends to re-aggregate, resulting in larger domains than intended, or the release agent remaining on the toner surface. This can lead to adhesion to the photoreceptor during actual imaging, especially in high-temperature, high-humidity environments, causing problems such as filming. Furthermore, if the average SF2 value is greater than 300, the release agent is highly likely to be surrounded by substances with similar properties, such as solubility parameters, resulting in the release agent becoming miscible with surrounding substances and failing to fully function. This prevents the release agent from seeping to the toner surface during high-temperature fixing, resulting in problems such as offset images and reduced gloss.

[0016] Specific methods for measuring Sw / Sa and SF2 will be described later in the examples. In the present invention, it is preferable that 60% or more of the toner satisfies the above-mentioned relational expressions (1) and (2). By satisfying the above-mentioned relational expressions (1) and (2), it becomes possible to suppress filming in a high-temperature, high-humidity environment and to achieve good releasability during fixing. When 60% or more of such toner is present, it becomes possible to obtain even better effects.

[0017] <Polyester resin> The weight average molecular weight (Mw) is preferably 7000 to 10000, more preferably 7500 to 9500, and even more preferably 8000 to 9000. The weight average molecular weight (Mw) / number average molecular weight (Mn) is preferably 5 or less, and more preferably 4 or less. The polyester resin used in the present invention may be any of those obtained by a polycondensation reaction between a generally known alcohol and an acid. For example, alcohols include diols such as polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, and 1,4-butenediol; etherified bisphenols such as 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylenated bisphenol A; and saturated or unsaturated bisphenols having 3 to 22 carbon atoms. Dihydric alcohol units substituted with hydrocarbon groups, other dihydric alcohol units, trihydric or higher alcohol monomers such as sorbitol, 1,2,3,6-hexanetetrol, 1,4-salbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene. Examples of carboxylic acids used to obtain polyester resins include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, and malonic acid, divalent organic acid monomers obtained by substituting these with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, anhydrides of these acids, dimers of lower alkyl esters and linoleic acid, and 1,2,4-benzotriazoles. Examples of suitable carboxylic acid monomers include tricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, embolic trimer acid, and anhydrides of these acids.

[0018] <Aromatic petroleum resin> The aromatic petroleum resin used in the present invention is preferably a styrene-based resin, and examples thereof include polymers of styrene and its substitution products, such as polystyrene, poly-p-styrene, and polyvinyltoluene; styrene-based copolymers such as 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. The glass transition temperature of the aromatic petroleum resin used in the present invention is preferably 70 to 90° C., and more preferably 75 to 85° C. If the glass transition temperature is lower than 70° C., the heat-resistant storage stability of the toner decreases, and if it is higher than 90° C., the low-temperature fixability deteriorates. The glass transition point (Tg) in the present invention was determined by using a differential scanning calorimeter (DSC210, manufactured by Seiko Instruments Inc.) to measure 0.01 to 0.02 g of a sample into an aluminum pan, heating the sample to 150°C, and then cooling the sample from that temperature at a rate of 10°C / min to 20°C. The sample was then heated again at a rate of 10°C / min, and the glass transition point was determined as the temperature at the intersection of an extension of the baseline below the highest endothermic peak temperature and a tangent line showing the maximum slope from the rising part of the peak to the peak apex. The content of the aromatic petroleum resin is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 to 15 parts by mass, more preferably 7 to 10 parts by mass, per 100 parts by mass of the toner. If the content is less than 5 parts by mass, the pulverizability during toner pulverization decreases, and the productivity of the pulverized toner decreases. If the content is more than 15 parts by mass, the low-temperature fixability deteriorates.

[0019] <Coloring agent> The colorant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the colorant 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), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, and anthrazan yellow BG. L, Isoindolinone Yellow, Bengala, Red Lead, Cinnabar, Cadmium Red, Cadmium Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise Red, Parachlor Orthonitroaniline Red, Lithol 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, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine, Prussian Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake,Examples include malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc oxide, and lithopone. These may be used alone or in combination of two or more.

[0020] The content of the colorant is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 part by mass or more and 15 parts by mass or less, and more preferably 3 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the toner.

[0021] <External additives> Examples of external additives include abrasives such as silica, Teflon (registered trademark) resin powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder, and strontium titanate powder, fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder, anti-aggregation agents, resin powders, and conductivity-imparting agents such as zinc oxide powder, antimony oxide powder, and tin oxide powder, as well as white and black fine particles of opposite polarity that can be used as developability improvers. These can be used alone or in combination, and are selected so as to provide resistance to development stresses such as idle spin.

[0022] <Other ingredients> The other components are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a release agent, a charge control agent, a flowability improver, a cleaning property improver, and a magnetic material.

[0023] <Release agent> The release agent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the waxes include vegetable waxes such as carnauba wax, cotton wax, and wood wax / rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cerusine; 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. Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons; low-molecular-weight crystalline polymer resins, such as homopolymers or copolymers of polyacrylates as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate (for example, copolymers of n-stearyl acrylate and 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. Hydrocarbon waxes have low compatibility with common polyester resins, so they tend to seep out onto the surface during fixing, providing high release properties and ensuring high gloss and low-temperature fixability.

[0024] The melting point of the release agent is not particularly limited and can be appropriately selected depending on the purpose, but the melting point is preferably 80° C. or higher and 100° C. or lower. If the melting point is lower than 80° C., the heat-resistant storage stability deteriorates, and if the melting point is higher than 100° C., the low-temperature fixability deteriorates.

[0025] The content of the release agent is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 2 to 6 parts by mass, more preferably 3 to 5 parts by mass, relative to 100 parts by mass of the toner. If the content is less than 2 parts by mass, the release agent does not bleed to the surface during fixing, resulting in poor release properties and reduced low-temperature fixability and high-temperature offset resistance. If the content is more than 6 parts by mass, the amount of release agent precipitated on the toner surface increases, reducing the storage stability and fluidity of the toner, worsening filming on the photoreceptor, etc., and reducing the transportability of the residual toner.

[0026] -Charge control agent- The charge control agent is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substance or compounds, tungsten simple substance or compounds, fluorine-based activators, metal salicylate, and metal salts of salicylic acid derivatives. Specific examples include the nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, the salicylic acid metal complex E-84, and the phenolic condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (both manufactured by Hodogaya Chemical Co., Ltd.), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

[0027] The content of the charge control agent is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 0.2 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the toner.

[0028] -Flow improver- The flowability improver is not particularly limited and can be appropriately selected depending on the purpose as long as it can increase hydrophobicity by surface treatment and prevent deterioration of flowability and chargeability even under high humidity, and examples thereof include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils, etc. Silica and titanium oxide as the external additives are preferably surface-treated with such flowability improvers and used as hydrophobic silica and hydrophobic titanium oxide.

[0029] -Cleaning improver- The cleaning property improver is not particularly limited and can be appropriately selected depending on the purpose as long as it is added to the toner to remove the developer remaining on the photoreceptor or primary transfer medium after transfer, and examples thereof include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and are suitably those with a volume average particle size of 0.01 μm to 1 μm.

[0030] -Magnetic materials- The magnetic material is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include iron powder, magnetite, ferrite, etc. Among these, white materials are preferred in terms of color tone.

[0031] <Developer> The toner of the present invention can be used as a developer. The developer may be either a one-component developer or a two-component developer. When the developer is a two-component developer, it contains the toner of the present invention and a carrier.

[0032] The carrier is not particularly limited and can be appropriately selected depending on the purpose, but is preferably one having a core material and a resin layer covering the core material.

[0033] The material for the core is not particularly limited and can be appropriately selected depending on the purpose, and for example, manganese-strontium (Mn-Sr)-based materials and manganese-magnesium (Mn-Mg)-based materials with a density of 50 emu / g to 90 emu / g are preferred, and from the viewpoint of ensuring image density, highly magnetic materials such as iron powder (100 emu / g or more) and magnetite (75 emu / g to 120 emu / g) are preferred. Furthermore, weakly magnetic materials such as copper-zinc (Cu-Zn)-based materials (30 emu / g to 80 emu / g) are preferred because they can weaken the contact of the toner with the photoreceptor in a standing state, which is advantageous for improving image quality. These may be used alone or in combination of two or more.

[0034] The volume average particle size of the core material is preferably 25 μm or more and 200 μm or less.

[0035] The material for the resin layer is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, polyester resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene resins, copolymers of vinylidene fluoride and an acrylic monomer, copolymers of vinylidene fluoride and vinyl fluoride, fluoro terpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and a non-fluorinated monomer, and silicone resins. These may be used alone or in combination of two or more.

[0036] When the developer is a two-component developer, the mixture ratio of the toner and the carrier (mass ratio of the toner to the carrier) is preferably 2.0% by mass or more and 12.0% by mass or less, and more preferably 2.5% by mass or more and 10.0% by mass or less.

[0037] (Toner manufacturing method) The method for producing the toner of the present invention includes a step of producing toner base particles containing a polyester resin, a release agent, and an aromatic petroleum resin, and may include other steps as necessary. The amount of the aromatic petroleum resin added in the production process of the toner base particles is preferably 5 parts by mass or more and 10 parts by mass or less, when the total amount of the toner base particles is 100 parts by mass.

[0038] <Toner base particle manufacturing process> In the toner base particle manufacturing process, the above-mentioned toner materials are mixed, kneaded, pulverized, and classified to obtain toner base particles (colored particles) having a desired particle size. If necessary, the toner base particles can be mixed with other components such as inorganic fine particles (other processes).

[0039] Specifically, the above components are first thoroughly mixed in a mixer such as a Henschel mixer, and then the constituent materials are thoroughly kneaded using a continuous twin-screw extruder (e.g., a KTK twin-screw extruder manufactured by Kobe Steel, Ltd., a TEM twin-screw extruder manufactured by Toshiba Machine Co., Ltd., a PCM twin-screw extruder manufactured by Ikegai Iron Works, or a KEX twin-screw extruder manufactured by Kurimoto Iron Works) or a continuous single-screw kneader (e.g., a thermal kneader such as a Buss Ko-Kneader or a KCK kneader). Methods that can be used to increase the specific energy include reducing the kneading throughput or lowering the kneader temperature setting and kneading the mixture in a high-viscosity state. Next, after cooling the kneaded product, it is roughly pulverized using a hammer mill or the like, and further pulverized finely using a fine pulverizer using a jet airflow or a mechanical pulverizer, and then classified to a predetermined particle size using a classifier using a swirling airflow or a classifier using the Coanda effect. The classification can be performed by removing fine particle portions using, for example, a cyclone, a decanter, a centrifugal separator, etc. After the pulverization and classification are completed, the pulverized material is classified in an air current by centrifugal force or the like to produce a toner having a predetermined particle size.

[0040] The weight average particle size of the toner obtained by the toner production method is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 4 μm or more and 10 μm or less, and more preferably 5 μm or more and 8 μm or less. The method for measuring the weight average particle diameter is not particularly limited and can be appropriately selected depending on the purpose, and can be measured using, for example, a measuring device for measuring the particle size distribution of toner particles by the Coulter Counter method. Examples of such measuring devices include the Coulter Counter TA-II (manufactured by Coulter) and the Coulter Multisizer II (manufactured by Coulter).

[0041] (Toner storage unit) The toner storage unit of the present invention stores the toner of the present invention. By mounting the toner storage unit of the present invention in an image forming apparatus and forming an image using the toner of the present invention, an image having excellent low-temperature fixability and heat-resistant storage stability can be obtained.

[0042] The toner storage unit of the present invention refers to a unit having a function of storing the toner of the present invention, in which the toner of the present invention is stored. Examples of the toner storage unit include a toner storage container, a developing unit, and a process cartridge. The toner container refers to a container that contains toner. The developing device has a means for storing and developing toner.

[0043] The process cartridge includes at least an electrostatic latent image carrier that carries an electrostatic latent image, and a developing unit that develops the electrostatic latent image carried on the electrostatic latent image carrier with toner to form a visible image, and may further include other units such as a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, and a discharging unit, which are appropriately selected as necessary. The developing means includes at least a developer container that contains the toner or developer of the present invention, and a developer carrier that carries and transports the toner or developer contained in the developer container, and may further include a layer thickness regulating member for regulating the thickness of the toner layer to be carried. The process cartridge can be detachably mounted in various electrophotographic apparatuses, facsimiles, and printers, and is preferably detachably mounted in the image forming apparatus of the present invention, which will be described later.

[0044] (Image forming method and image forming apparatus) The image forming apparatus of the present invention includes an electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, 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, transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium, and may further include other means such as a static eliminating means, a cleaning means, a recycling means, and a control means, as necessary. 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, 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 eliminating step, a cleaning step, a recycling step, and a control step, as necessary.

[0045] -Electrostatic latent image forming process and electrostatic latent image forming means- The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image bearing member. 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 forming step can be suitably carried out by the electrostatic latent image forming means.

[0046] The 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 ones. A preferred shape is a drum, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Examples of the organic photoreceptor include a laminated photoreceptor having a laminated structure in which a layer (charge generation layer) in which a charge generation material such as metal-free phthalocyanine or titanyl phthalocyanine is dispersed in a binder resin and a layer (charge transport layer) in which a charge transport material is dispersed in a binder resin are stacked on a support such as an aluminum drum, and a single-layer photoreceptor having a single-layer photosensitive layer in which both a charge generation material and a charge transport material are dispersed in a binder resin on a support. In the single-layer type photoreceptor, a hole transport material and an electron transport material can be added to the photosensitive layer as charge transport materials. An undercoat layer may be provided between the support and the multilayer charge generating layer or the single-layer photosensitive layer.

[0047] The electrostatic latent image can be formed, for example, by uniformly charging the surface of the electrostatic latent image bearing member and then exposing it to light in an imagewise manner.

[0048] The electrostatic latent image forming means preferably has at least a charging means (charger) for uniformly charging the surface of the electrostatic latent image carrier, and an exposure means (exposure device) for imagewise exposing the surface of the electrostatic latent image carrier.

[0049] The charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using the charger. The charger is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a known contact charger equipped with a conductive or semiconductive roll, brush, film, rubber blade, etc., and a non-contact charger utilizing corona discharge such as a corotron or scorotron. The charger is preferably one that is arranged in contact or non-contact with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by applying a superimposed DC and AC voltage to it, or one that is a charging roller that is arranged in close proximity to the electrostatic latent image carrier but not in contact with it via a gap tape and charges the surface of the electrostatic latent image carrier by applying a superimposed DC and AC voltage to the charging roller.

[0050] The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member to light in an imagewise manner using the exposure unit. The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image bearing member charged by the charger in the form of an image to be formed, and can be appropriately selected depending on the purpose. Examples of the exposure device include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. In the present invention, a backlight system may be employed in which exposure is performed imagewise from the back side of the electrostatic latent image bearing member.

[0051] -Developing process and developing means- The developing step is a step of developing the electrostatic latent image formed on the electrostatic latent image carrier with the toner to form a toner image. The developing unit is a unit that develops the electrostatic latent image formed on the electrostatic latent image carrier with the toner to form a toner image. The developing step can be suitably carried out by the developing means.

[0052] The toner image can be formed, for example, by developing the electrostatic latent image with the toner. The developing means preferably includes at least a developing device that contains the toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner, and more preferably includes a developing device that includes a toner container. The developing device may be a single-color developing device or a multi-color developing device, and a suitable example is one having an agitator that charges the toner by frictional agitation and a rotatable magnetic roller.

[0053] The development method may be a premix development method, in which a premix developer in which toner and carrier are mixed in advance is replenished. In the premix development method, the excess carrier in the developing device is discharged as excess developer. This gradually refreshes the developer in the developing device. This can extend the replacement cycle due to developer deterioration and eliminate the effort required for developer replacement.

[0054] -Transfer process and transfer means- The transfer step is a step of transferring the toner image formed on the electrostatic latent image carrier onto the surface of a recording medium. The transfer means is a means for transferring the toner image formed on the electrostatic latent image carrier onto the surface of a recording medium. The transfer step can be suitably carried out by the transfer means.

[0055] The transfer step is preferably carried out using an intermediate transfer body, where a toner image is primarily transferred onto the intermediate transfer body, and then the toner image is secondarily transferred onto the recording medium. A more preferred embodiment includes a first transfer step in which two or more colors, preferably full-color toner, are used as the toner, and the toner image is transferred 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 (primary transfer means and secondary transfer means) preferably includes at least a transfer device that peels and charges the toner image formed on the electrostatic latent image carrier (photosensitive member) onto the recording medium. The number of transfer devices may be one or more. Examples of the transfer device include a corona transfer device that uses corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

[0056] The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

[0057] - Fixing process and fixing means - The fixing step is a step of fixing the toner image transferred onto the surface of the recording medium. The fixing unit is a unit for fixing the toner image transferred onto the surface of the recording medium. The fixing step can be suitably carried out by the fixing means.

[0058] The fixing step may be carried out each time the developer of each color is transferred to the recording medium, or may be carried out simultaneously with the developers of each color stacked together. The fixing device as the fixing means is not particularly limited and can be appropriately selected depending on the purpose, but known heating and pressurizing means are suitable, such as a combination of a heating roller and a pressure roller, or a combination of a heating roller, a pressure roller and an endless belt.

[0059] -Static removal process and static removal means- The charge removal step is a step of removing electricity by applying a charge removal bias to the electrostatic latent image bearing member. The charge removing unit is a unit that applies a charge removing bias to the electrostatic latent image bearing member to remove electricity. The charge removal step can be suitably carried out by the charge removal means.

[0060] The discharging means is not particularly limited as long as it can apply a discharging bias to the electrostatic latent image bearing member, and can be appropriately selected from known discharging devices, such as a discharging lamp.

[0061] -Cleaning process and cleaning means- The cleaning step is a step of removing the toner remaining on the electrostatic latent image bearing member. The cleaning means is a means for removing the toner remaining on the electrostatic latent image carrier. The cleaning step can be suitably carried out by the cleaning means.

[0062] 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 a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

[0063] -Recycling process and means- The recycling step is a step of recycling the toner removed in the cleaning step to the developing means. The recycling unit is a unit for recycling the toner removed by the cleaning unit to the developing unit. There are no particular limitations on the recycling unit, and examples of the recycling unit include known transport units. The recycling step can be suitably carried out by the recycling means.

[0064] -Control process and control means- The control step is a step of controlling each of the steps. The control means is a means for controlling each of the means. The control step can be suitably carried out by the control means. The control means is not particularly limited as long as it can control the movement of each of the means, and can be appropriately selected depending on the purpose. Examples of the control means include devices such as a sequencer and a computer.

[0065] (Manufacturing method for printed matter) The method for producing a printed matter of the present invention forms a printed matter on a recording medium using an image forming apparatus including: an electrostatic latent image carrier; an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier; a developing unit that develops the electrostatic latent image formed on the electrostatic latent image carrier with the toner to form a toner image; a transfer unit that transfers the toner image formed on the electrostatic latent image carrier to the surface of a recording medium; and a fixing unit that fixes the toner image transferred to the surface of the recording medium. The method may include other steps as necessary. The printed matter has an image formed on the recording medium using the toner of the present invention. Each step in the method for producing a printed matter can be the same as that in the image forming method, and therefore a duplicated description will be omitted.

[0066] Here, an embodiment of an image forming apparatus of the present invention will be described with reference to the drawings, but the present invention is not limited to this embodiment. In each drawing, the same components are denoted by the same reference numerals, and redundant explanations may be omitted. Furthermore, the number, position, shape, etc. of the following components are not limited to this embodiment, and may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0067] FIG. 1 is a schematic diagram illustrating an embodiment of an image forming apparatus according to the present invention. The image forming apparatus 100A includes a photosensitive drum 10, a charging roller 20, an exposure device, a developing device 40, an intermediate transfer belt 50, a cleaning device 60 having a cleaning blade, and a discharging lamp . The intermediate transfer belt 50 is an endless belt stretched by three rollers 51 arranged inside, and can move in the direction of the arrow in Figure 1. Some of the three rollers 51 also function as transfer bias rollers that can apply a transfer bias (primary transfer bias) to the intermediate transfer belt 50. A cleaning device 90 having a cleaning blade is arranged near the intermediate transfer belt 50. Furthermore, a transfer roller 80 that can apply a transfer bias (secondary transfer bias) to transfer a toner image onto transfer paper 95 is arranged opposite the intermediate transfer belt 50. In addition, a corona charging device 58 for applying an electric charge to the toner image transferred onto the intermediate transfer belt 50 is arranged around the intermediate transfer belt 50, between the contact point between the photosensitive drum 10 and the intermediate transfer belt 50 and the contact point between the intermediate transfer belt 50 and the transfer paper 95, in the direction of rotation of the intermediate transfer belt 50.

[0068] In this embodiment, an elastic intermediate transfer belt can also be used as the intermediate transfer belt 50. As the elastic intermediate transfer belt, for example, one in which a flexible elastic layer is laminated on a base layer having a rigidity that allows for relatively flexible properties can be used. In order to prevent the intermediate transfer belt 50 from meandering, a guide member for preventing deviation may be provided on the inner peripheral surface of the intermediate transfer belt 50 .

[0069] The developing device 40 is composed of a developing belt 41 and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C arranged around the developing belt 41. Each developing unit 45 includes a developer container 42, a developer supply roller 43, and a developing roller (developer carrier) 44. The developing belt 41 is an endless belt stretched over multiple belt rollers and can move in the direction of the arrow in FIG. 1. A portion of the developing belt 41 contacts the photosensitive drum 10.

[0070] Next, a method for forming an image using image forming apparatus 100A will be described. First, the surface of the photosensitive drum 10 is uniformly charged using the charging roller 20, and then an exposure device (not shown) exposes the photosensitive drum 10 to exposure light L to form an electrostatic latent image. Next, the electrostatic latent image formed on the photosensitive drum 10 is developed with toner supplied from the developing device 40 to form a toner image. Furthermore, the toner image formed on the photosensitive drum 10 is transferred (primary transfer) onto the intermediate transfer belt 50 by a transfer bias applied from the roller 51, and then transferred (secondary transfer) onto the transfer paper 95 by a transfer bias applied from the transfer roller 80. Meanwhile, the photosensitive drum 10 from which the toner image has been transferred onto the intermediate transfer belt 50 has residual toner removed by the cleaning device 60, and is then discharged by the discharge lamp 70.

[0071] FIG. 2 is a schematic explanatory diagram for explaining another embodiment of the image forming apparatus of the present invention. Image forming apparatus 100B has the same configuration as image forming apparatus 100A, except that it does not have a developing belt 41 and has a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C arranged directly opposite each other around photosensitive drum 10.

[0072] FIG. 3 is a schematic explanatory view for explaining still another embodiment of the image forming apparatus of the present invention. Image forming apparatus 100C is a tandem type color image forming apparatus, and includes a copying machine main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

[0073] An intermediate transfer belt 50 provided in the center of the copying machine main body 150 is an endless belt stretched over three rollers 14, 15, and 16, and can move in the direction of the arrow in FIG. A cleaning device 17 having a cleaning blade for removing toner remaining on the intermediate transfer belt 50 after the toner image has been transferred to the recording paper is disposed near the roller 15. Facing the intermediate transfer belt 50 stretched by the rollers 14 and 15, yellow, cyan, magenta, and black image forming units 120 are arranged side by side along the conveyance direction.

[0074] An exposure device 21 is disposed near the image forming unit 120. A secondary transfer belt 24 is disposed on the side of the intermediate transfer belt 50 opposite the side where the image forming unit 120 is disposed. The secondary transfer belt 24 is an endless belt stretched over a pair of rollers 23, and the recording paper transported on the secondary transfer belt 24 and the intermediate transfer belt 50 can come into contact with each other between the rollers 16 and 23.

[0075] Also, near the secondary transfer belt 24 is disposed a fixing device 25 that includes a fixing belt 26, which is an endless belt stretched over a pair of rollers, and a pressure roller 27 that is positioned so as to be pressed against the fixing belt 26. Also, near the secondary transfer belt 24 and the fixing device 25 is disposed a sheet inverting device 28 for inverting the recording paper when forming images on both sides of the recording paper.

[0076] Next, a method for forming a full-color image using image forming apparatus 100C will be described. First, a color document is placed on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a color document is placed on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed. When the start switch is pressed, if an original is set on the automatic document feeder 400, the original is transported and moved onto the contact glass 32, and on the other hand, if the original is set on the contact glass 32, the scanner 300 is driven and the first traveling body 33 equipped with a light source and the second traveling body 34 equipped with a mirror start moving. At this time, light irradiated from the first traveling body 33 is reflected from the surface of the original, reflected by the second traveling body 34, and then received by the reading sensor 36 via the imaging lens 35, thereby reading the original and obtaining image information in black, yellow, magenta, and cyan.

[0077] The image information for each color is transmitted to the image forming means 18 in the image forming unit 120 for each color, and a toner image for that color is formed. As shown in Fig. 4, each image forming unit 120 for each color includes a photosensitive drum 10, a charging roller 160 that uniformly charges the photosensitive drum 10, an exposure device that exposes the photosensitive drum 10 to exposure light L based on the image information for that color to form an electrostatic latent image for that color, a developing device 61 that develops the electrostatic latent image with a developer of that color to form a toner image for that color, a transfer roller 62 that transfers the toner image onto the intermediate transfer belt 50, a cleaning device 63 having a cleaning blade, and a discharging lamp 64. The toner images of each color formed by the image forming units 120 of each color are sequentially transferred (primary transfer) onto the intermediate transfer belt 50, which is stretched and moved by rollers 14, 15, and 16, and are superimposed to form a composite toner image.

[0078] On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed recording paper from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, which is separated one sheet at a time by the separation roller 145 and sent to the paper feed path 146, and then conveyed by the conveyance roller 147 and guided to the paper feed path 148 in the copying machine main body 150, where it is stopped by hitting the registration roller 49. Alternatively, the paper feed roller is rotated to feed recording paper from the manual feed tray 54, which is separated one sheet at a time by the separation roller 52 and guided to the manual feed path 53, where it is stopped by hitting the registration roller 49. The registration roller 49 is generally grounded when in use, but may be used with a bias applied to it in order to remove paper dust from the recording paper.

[0079] Next, the registration rollers 49 are rotated in synchronization with the composite toner image formed on the intermediate transfer belt 50, thereby feeding the recording paper between the intermediate transfer belt 50 and the secondary transfer belt 24, and the composite toner image is transferred (secondary transfer) onto the recording paper. Any toner remaining on the intermediate transfer belt 50 after the composite toner image has been transferred is removed by the cleaning device 17. It is also possible to provide a collecting means for receiving the toner etc. removed by the cleaning device 17. A dish-shaped tray or the like can be used as the collecting means.

[0080] The recording paper onto which the composite toner image has been transferred is transported by secondary transfer belt 24, and then the composite toner image is fixed by fixing device 25. Next, the transport path of the recording paper is switched by switching claw 55, and the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56. Alternatively, the transport path of the recording paper is switched by switching claw 55, the sheet is inverted by sheet inverting device 28, an image is formed on the back side in the same manner, and then the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56.

[0081] Fig. 5 is a schematic diagram showing an example of a process cartridge according to the present embodiment. As shown in Fig. 5, a process cartridge 500 has a photosensitive drum 10, a corona charger 29 as a charging unit, a developing device 40, a cleaning device 60, and a transfer roller 62. In Fig. 5, P indicates transfer paper, and L indicates exposure light.

[0082] The image forming apparatus and image forming method of the present invention use the toner of the present invention, which can achieve both excellent low-temperature fixability and heat-resistant storage stability and can maintain good image quality even in high-temperature, high-humidity environments, and therefore can provide high-quality images for a long period of time. [Example]

[0083] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0084] Example 1 <Preparation of amorphous polyester resin> The monomer species shown in Table 1 below and tetrabutoxy titanate as a condensation catalyst were placed in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and the reaction was carried out at 230°C for 6 hours under a nitrogen stream while distilling off the water produced. The reaction was then carried out for 1 hour under a reduced pressure of 5 to 20 mmHg to obtain an amorphous polyester resin. In Table 1, the "25 mol%" shown for bisphenol A (2,2) propylene oxide refers to the proportion of the alcohol component when the acid component and alcohol component are 50 mol% and 50 mol%, respectively.

[0085] [Table 1]

[0086] <Preparation of crystalline polyester resin> A 5L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with fumaric acid and 1,6-hexanediol so that the OH / COOH ratio was 0.9, and the mixture was reacted with titanium tetraisopropoxide (500 ppm relative to the resin components) at 180°C for 10 hours, then heated to 200°C and reacted for 3 hours. The mixture was further reacted for 2 hours at a pressure of 8.3 kPa to obtain a crystalline polyester resin.

[0087] <Preparation of toner base particles> The following materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) under the following premixing conditions. [Pre-mixing conditions]: 1400 rpm, 1 min on, 2 min off x 5 Amorphous polyester resin: 89.5 parts Crystalline polyester resin: 4.5 parts Styrene-α-methylstyrene copolymer: 8.0 parts (SA140, manufactured by Kraton, Tg value 87°C) Hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.): 3.0 parts Carbon black (#44, manufactured by Mitsubishi Chemical Corporation): 13 parts

[0088] The resulting kneaded material was rolled to a thickness of 4.0 mm using a roller, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, it was finely pulverized using a supersonic jet pulverizer, Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening to obtain toner base particles with a weight average particle size of 6.8 μm±0.3 μm. Although the catalog value for the Tg value of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) is 87°C, there is a variation of about ±5°C depending on the production rod, so the Tg value was measured in advance using the following measurement method. The same applies to the following examples and comparative examples.

[0089] [Method for measuring Tg value] Approximately 5.0 mg of the target sample was placed in an aluminum sample container, which was then placed on a holder unit and set in an electric furnace. The sample was then heated from -80°C to 150°C at a rate of 10°C / min under a nitrogen atmosphere, and the glass transition temperature (Tg) of the target sample was determined from the DSC curve obtained using the analysis program in the differential scanning calorimeter.

[0090] <Preparation of Toner Developer> One part of HDK-2000 (Clariant KK) as metal oxide fine particles was added to 100 parts of the obtained toner base particles by stirring and mixing in a Henschel mixer to prepare [Toner 1]. 5% of the obtained external additive-treated toner and 95% by mass of the coated ferrite carrier were mixed uniformly for 5 minutes at 48 rpm using a Turbula mixer (manufactured by WAB) to prepare [Toner Developer 1].

[0091] More specifically, the confirmation is carried out using the following procedure. First, the toner particles are thoroughly dispersed in a room-temperature curing epoxy resin, and then embedded and the epoxy resin is allowed to fully cure. A cross section of the toner is prepared using an ultramicrotome (ultrasonic), and stained using ruthenium tetroxide or osmium tetroxide as needed. This is then photographed at a magnification of 2000x or more using a scanning electron microscope (SEM (cold) Hitachi SU8230 (Hitachi High-Technologies Corporation)).

[0092] From the cross-sectional images of the toner obtained, the domain area of ​​the release agent present in the toner particle, the domain area of ​​the aromatic petroleum resin, and SF2 of the domain of the release agent were calculated, and the domain area Sw of the release agent and the domain area Sa of the aromatic petroleum resin were calculated from the obtained domain area data.

[0093] For the calculation, an image analysis method using the texture analysis technique of image analysis software "Azo-kun" (registered trademark, manufactured by Asahi Kasei Engineering Co., Ltd.) was used. Specifically, 100 toner cross-sectional images were selected, and the analysis conditions were the number of structures of "3" and the multi-value method of "manual." The domain area of ​​the release agent and the domain area of ​​the aromatic petroleum resin were separated and recognized, and from the respective domain areas obtained by separation and recognition, the domain area Sw of the release agent, the domain area Sa of the aromatic petroleum resin, and the shape coefficient SF2 indicating the degree of unevenness of the domain of the release agent were calculated. The average value of Sw / Sa for 100 toner particles was calculated and used as the Sw / Sa value. The average value of SF2 for 100 domains of the release agent in the measured toner was also calculated and used as the SF2 value.

[0094] [Evaluation of low-temperature fixability] The obtained toner developer was placed in a copier (RICOH IM C5510) manufactured by Ricoh Co., Ltd., and an image was output. 2 A solid image was output onto paper (Ricoh Co., Ltd., Type 6200) through exposure, development, and transfer processes. The fixing linear speed was 256 mm / sec. The fixing temperature was changed in 2°C increments to measure the lowest temperature at which cold offset did not occur (lowest fixing temperature: low-temperature fixability). The low-temperature fixability was evaluated based on the following evaluation criteria, and the results are shown in Table 2. A rating of "Fair" or better was deemed sufficient for practical use. -Evaluation criteria for low-temperature fixability- ◎: Less than 120℃ ○: 120℃ or higher but lower than 125℃ △: 125℃ or higher but lower than 130℃ ×: 130℃ or higher

[0095] [Hot offset resistance] The developer was placed in a storage unit of a copier (RICOH MPC 6003, manufactured by Ricoh Co., Ltd.), and the amount of the developer adhered was 0.4 mg / cm 2 A solid image was formed on a recording medium (Type 6200, manufactured by Ricoh Co., Ltd.) so that the image satisfies the following criteria: The fixing linear speed was 256 mm / sec, the NIP width of the fixing device was 11 mm, and the fixing temperature was sequentially changed in 5°C increments. The upper limit temperature at which hot offset did not occur (upper limit fixing temperature: hot offset property) was measured, and the hot offset property was evaluated based on the following criteria, with the results shown in Table 2. A rating of "Fair" or better was deemed sufficient for practical use. [Evaluation criteria] ◎: Upper limit fixing temperature is 200℃ or more 〇: Upper limit fixing temperature is 190℃ or more and less than 200℃ △: Upper limit fixing temperature is 180℃ or more and less than 190℃ ×: Upper limit fixing temperature is less than 180°C

[0096] [HH Filming Rating] The obtained toner developer was placed in a Ricoh Co., Ltd. copier (RICOH IM 9000) and run at a high temperature and high humidity (30°C, 90%) with 200,000 sheets printed at an image area ratio of 1.0%, after which the filming state on the photoreceptor was visually observed. Filming was evaluated based on the following evaluation criteria, and the results are shown in Table 2. A rating of "△" or better was deemed sufficient for practical use. -Filming evaluation criteria- ⊚: No toner deposits were observed on the photosensitive drum. ◯: Minute toner deposits can be seen on some parts of the photosensitive drum, but there is no effect on the image. △: A large amount of toner deposits can be seen on the photosensitive member, but there is no effect on the image. x: A large amount of toner deposits was observed on the photosensitive member, and an abnormality occurred in the image.

[0097] [MM Filming Rating] The obtained toner developer was placed in a Ricoh Co., Ltd. copier (RICOH IM C9000) and run at a medium temperature and medium humidity environment (23°C, 50%) with 200,000 sheets printed at an image area ratio of 1.0%, after which the filming state on the photoreceptor was visually observed. Filming was evaluated based on the following evaluation criteria, and the results are shown in Table 2. A rating of "△" or better was deemed sufficient for practical use. -Filming evaluation criteria- ⊚: No toner deposits were observed on the photosensitive drum. ◯: Minute toner deposits can be seen on some parts of the photosensitive drum, but there is no effect on the image. △: A large amount of toner deposits can be seen on the photosensitive member, but there is no effect on the image. x: A large amount of toner deposits was observed on the photosensitive member, and an abnormality occurred in the image.

[0098] Example 2 [Toner 2] and [Toner Developer 2] were prepared and evaluated in the same manner as in Example 1, except that 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, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 7.0 parts.

[0099] Example 3 [Toner 3] and [Toner Developer 3] were prepared and evaluated in the same manner as in Example 1, except that 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, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 9.5 parts.

[0100] Example 4 In Example 1, [Toner 4] and [Toner Developer 4] were prepared and evaluated in the same manner as in Example 1, except that the pre-mixing conditions were changed from 3.0 parts to 1.0 parts of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.).

[0101] Example 5 [Toner 5] and [Toner Developer 5] were prepared and evaluated in the same manner as in Example 1, except that the hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 3.0 parts to 4.0 parts.

[0102] Example 6 [Toner 6] and [Toner Developer 6] were prepared and evaluated in the same manner as in Example 1, except that the pre-mixing conditions were changed to 1200 rpm, 1 minute on, 2 minutes off x 4.

[0103] Example 7 [Toner 7] and [Toner Developer 7] were prepared and evaluated in the same manner as in Example 1, except that the pre-mixing conditions were changed to 1000 rpm, 1 minute on, 2 minutes off x 3.

[0104] Example 8 [Toner 8] and [Toner Developer 8] were prepared and evaluated in the same manner as in Example 1, except that the wax type in Example 1 was changed from a hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) to a rice brown wax (300VITA, manufactured by Clariant).

[0105] Example 9 [Toner 9] and [Toner Developer 9] were prepared and evaluated in the same manner as in Example 1, except that the styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) used in Example 1 was purchased and used with an upper Tg limit (Tg: 90°C).

[0106] Example 10 [Toner 10] and [Toner Developer 10] were prepared and evaluated in the same manner as in Example 1, except that a styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) with a lower Tg limit (Tg: 80°C) was obtained and used.

[0107] (Comparative Example 1) [Toner 11] and [Toner Developer 11] were prepared and evaluated in the same manner as in Example 1, except that 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 4, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 6.0 parts.

[0108] (Comparative Example 2) [Toner 12] and [Toner Developer 12] were prepared and evaluated in the same manner as in Example 1, except that 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 6, and the amount of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton) was changed from 8.0 parts to 10.0 parts.

[0109] (Comparative Example 3) [Toner 13] and [Toner Developer 13] were prepared and evaluated in the same manner as in Example 1, except that the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 3.0 parts to 0.7 parts.

[0110] Comparative Example 4 [Toner 14] and [Toner Developer 14] were prepared and evaluated in the same manner as in Example 1, except that the hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 3.0 parts to 4.5 parts.

[0111] [Table 2]

[0112] [Table 3]

[0113] For example, embodiments of the present invention are as follows. (1) A toner comprising toner particles containing a polyester resin, a release agent, and an aromatic petroleum resin, A toner for developing electrostatic images, characterized in that, when a cross section of the toner particle is observed with a scanning electron microscope, the domains of the release agent and the domains of the aromatic petroleum resin observed satisfy the following conditions 1 and 2: (Condition 1) For 100 toner particles, the average value of the ratio (Sw / Sa) of the domain area (Sw) of the release agent to the domain area (Sa) of the aromatic petroleum resin satisfies the following relational expression (1). 0.05≦Sw / Sa<0.5 (1) (Condition 2) The average value of the shape factor SF2 of the domain of the release agent for 100 toner particles satisfies the following relational expression (2). 150≦SF2≦300 (2) (2) The toner according to (1) above, wherein 60% or more of the toner satisfies the conditions 1 and 2. (3) The toner according to (1) or (2) above, wherein the release agent contains a hydrocarbon wax. (4) The toner according to any one of (1) to (3) above, wherein the aromatic petroleum resin has a glass transition temperature of 80° C. or higher and 90° C. or lower. (5) A developer comprising the toner according to any one of (1) to (4) above and a carrier. (6) A toner storage unit that stores the toner according to any one of (1) to (4) above. (7) 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 unit that develops the electrostatic latent image formed on the electrostatic latent image carrier using the toner according to any one of (1) to (4) above to form a toner image; a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium; a fixing unit for fixing the toner image transferred onto the surface of the recording medium. (8) 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 (1) to (4) above to form a toner image; a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium. (9) A method for producing a printed matter, comprising forming a toner image on a recording medium using the image forming apparatus described in (7) above. (10) A method for producing the toner according to any one of (1) to (4) above, comprising the steps of: The method includes a process for producing toner base particles containing a polyester resin, a release agent, and an aromatic petroleum resin, a toner manufacturing method, characterized in that the amount of the aromatic petroleum resin added in the manufacturing process of 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. [Explanation of symbols]

[0114] 10 Electrostatic latent image carrier (photosensitive drum) 14 Laura 15 Laura 16 Laura 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure equipment 22 Secondary transfer device 23 Laura 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet inverting device 29 Corona charger 32 Contact Glass 33 First running body 34 Second running body 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developer compartment 42Y Developer storage unit 42M Developer compartment 42C Developer storage unit 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 Development Unit 45Y Yellow Development Unit 45M Magenta Development Unit 45C Cyan Development Unit 49 Registration roller 50 Intermediate transfer belt 51 Laura 52 Separation roller 53 Manual feed path 54 Manual feed tray 55 Switching claw 56 Discharge roller 57 Output tray 58 Corona charging device 60 Cleaning Device 61 Developing device 62 Transfer roller 63 Photoconductor cleaning device 64 Static elimination lamp 70 Static elimination lamp 80 Transfer roller 90 Cleaning Device 95 Transfer paper 100A Image forming device 100B Image forming device 100C image forming device 120 Image forming unit 130 manuscript table 142 Paper feed roller 143 Paper Bank 144 Paper cassette 145 Separation roller 146 Paper feed path 147 Conveyor roller 148 Paper feed path 150 Copying device body 200 Paper feed table 300 scanner 400 Automatic Document Feeder (ADF) 500 Process Cartridge [Prior art documents] [Patent documents]

[0115] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-62599 [Patent Document 2] Patent Publication No. 2021-144186 [Patent Document 3] Japanese Patent Publication No. 2023-047237

Claims

1. A toner comprising toner particles containing a polyester resin, a release agent, and an aromatic petroleum resin, A toner for developing electrostatic images, characterized in that, when a cross section of the toner particle is observed with a scanning electron microscope, the domains of the release agent and the domains of the aromatic petroleum resin observed satisfy the following conditions 1 and 2: (Condition 1) In 100 toner particles, the average value of the ratio (Sw / Sa) of the domain area (Sw) of the release agent to the domain area (Sa) of the aromatic petroleum resin satisfies the following relational expression (1). 0.05≦Sw / Sa<0.5 (1) (Condition 2) The average value of the shape factor SF2 of the domain of the release agent for 100 toner particles satisfies the following relational expression (2). 150≦SF2≦300 (2)

2. 2. The toner according to claim 1, wherein 60% or more of the toner satisfies the conditions 1 and 2.

3. 2. The toner of claim 1, wherein the release agent comprises a hydrocarbon wax.

4. 2. The toner according to claim 1, wherein the aromatic petroleum resin has a glass transition temperature of 80°C or higher and 90°C or lower.

5. A developer comprising the toner according to claim 1 and a carrier.

6. A toner storage unit containing the toner according to any one of claims 1 to 4.

7. 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 unit that develops the electrostatic latent image formed on the electrostatic latent image carrier with the toner according to any one of claims 1 to 4 to form a toner image; a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium; a fixing unit for fixing the toner image transferred onto the surface of the recording medium.

8. 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 with the toner according to claim 1 to form a toner image; a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium.

9. A method for producing a printed matter, comprising forming a toner image on a recording medium using the image forming apparatus according to claim 7.

10. A method for producing the toner according to any one of claims 1 to 4, comprising the steps of: The method includes a process for producing toner base particles containing a polyester resin, a release agent, and an aromatic petroleum resin, a toner production method, characterized in that the amount of the aromatic petroleum resin added in the production process of 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.

Images