Toner, toner stored unit, image forming apparatus, image forming method, method for producing printed material, and method for producing toner

Abstract

To provide a toner excellent in low-temperature fixability and capable of achieving both suppression of filming in a high-temperature and high-humidity environment and releasability during fixing.SOLUTION: The toner includes toner particles satisfying the following conditions A1 and A2. A1: A total area of the releasing agent domains in the cross sections of the toner particles is 5% or less of an area of the cross sections of the toner particles. A2: in the cross section of the toner particles, there are release agent domains having a true-circle equivalent diameter calculated from a release agent domain perimeter of 0.2 μm or more and 0.8 μm or less and a circularity defined by the following formula (1) of 0.8 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner, 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 using toner for developing electrostatic latent images. 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 of use of image forming apparatuses, there is an increasing demand for low-temperature fixing of toners. As a method for low-temperature fixing of toners, a technique using a combination of an amorphous polyester resin and a crystalline polyester resin is known.

[0004] For example, Patent Document 1 discloses an electrophotographic toner that is produced by pulverizing and classifying a composition in which a styrene-based resin having a mass average molecular weight (Mw) of more than 3000 is internally added to a mixture of a binder resin and a colorant, with the aim of providing a toner that is excellent in pulverizability during production and excellent in fixing stability.

[0005] Furthermore, Patent Document 2 discloses a pulverized toner in which the maximum peak ratio of polyester resin to styrene resin measured by FT-IR is specified, with the aim of providing a pulverized toner that can achieve both low-temperature fixability and heat-resistant storage stability.

[0006] Furthermore, Patent Document 3 discloses a toner for developing electrostatic images, which contains a binder resin and a release agent and is intended to provide a toner for developing electrostatic images that can achieve both good releasability of fixed images and suppression of a decrease in image density when images are continuously formed in a low-temperature, low-humidity environment. The toner has toner particles in which, when the area of ​​the entire cross section of the toner particle is St, the total area of ​​the cross sections of domains of the release agent whose major axes are 10 nm or more and 500 nm or less is Sa, and the total area of ​​the cross sections of domains of the release agent whose major axes are 1500 nm or more and 3000 nm or less is Sb, the area fraction Sa / St is 2% or more and the area fraction Sb / St is 20% or more. Summary of the Invention [Problem to be solved by the invention]

[0007] However, with the toners described in Patent Documents 1 to 3, there is a concern that wax or polyester resin with low heat resistance exposed on the toner surface may adhere to the electrostatic latent image carrier, resulting in filming, which can cause image defects. Such defects are particularly noticeable in high-temperature, high-humidity environments, and image defects are even more pronounced when the printing area is small. On the other hand, reducing the amount of wax used tends to reduce release properties during fixing, so achieving both filming prevention and release properties during fixing in high-temperature, high-humidity environments is a challenge.

[0008] An object of one embodiment 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]

[0009] In order to solve the above problems, one embodiment of the present invention is A toner comprising a binder resin, a release agent, and an aromatic petroleum resin, A toner is provided, which contains toner particles that satisfy the following conditions A1 and A2. A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle. A2: In the cross section of the toner particle, there is a release agent domain having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less.

[0010]

number

[0011] According to one embodiment of the present invention, it is possible to provide a toner that is excellent in low-temperature fixability, and that can simultaneously suppress filming in a high-temperature, high-humidity environment and provide good releasability during fixation. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a photograph taken by a scanning transmission electron microscope of a cross section of an example of a toner particle that is contained in a toner according to an embodiment of the present invention and satisfies conditions A1 and A2. [Figure 2] FIG. 2 is a schematic view illustrating an example of a toner storage unit according to an embodiment of the present invention. [Figure 3] 1 is a schematic diagram illustrating an example of a part of an image forming apparatus according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 5] FIG. 10 is a schematic diagram illustrating another example of a part of an image forming apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described in detail.

[0014] (toner) The toner of the present invention is A toner comprising a binder resin, a release agent, and an aromatic petroleum resin, The toner contains toner particles that satisfy the following conditions A1 and A2. A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle. A2: In the cross section of the toner particle, there is a release agent domain having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less.

[0015]

number

[0016] Such a toner has excellent low-temperature fixing properties, and can simultaneously suppress filming in a high-temperature, high-humidity environment and provide good releasability during fixing.

[0017] <Binder resin> The binder resin used in the toner of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but it preferably has a weight average molecular weight (Mw) of 7000 to 10000, more preferably 7500 to 9500, and even more preferably 8000 to 9000. When the weight average molecular weight (Mw) of the binder resin is 7000 or more, it is possible to prevent deterioration of hot offset resistance due to low molecular weight components, and when it is 10000 or less, it is possible to prevent deterioration of wax dispersibility due to high molecular weight components.

[0018] Furthermore, the binder resin used in the toner of the present invention preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 5 or less, more preferably 4 or less. Furthermore, the weight average molecular weight (Mw) / number average molecular weight (Mn) ratio is preferably 1 or more, more preferably 2 or more. When the weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of the binder resin is 2 or more, stable fixing properties are exhibited from low to high temperatures, and when it is 5 or less, it is possible to suppress the occurrence of quality issues due to extremely low molecular weight components or extremely high molecular weight components.

[0019] The binder resin used in the toner of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but polyester resin is preferred from the viewpoint of low-temperature fixability and design of fixability and glossiness.

[0020] <<Polyester resin>> The polyester resin used in the present invention may be any of those obtained by a generally known polycondensation reaction between an alcohol and an acid.

[0021] -alcohol- Examples of alcohols from which polyester resins can be obtained by polycondensation reaction 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 alcohols having 3 to 22 carbon atoms. and other dihydric alcohol units, and 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.

[0022] -acid- Examples of acids from which polyester resins can be obtained by polycondensation reaction include carboxylic acids, and specific examples thereof 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, and dimers of lower alkyl esters and linoleic acid. Examples thereof include trivalent or higher polyvalent carboxylic acid monomers such as 1,2,4-benzenetricarboxylic 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, embol trimer acid, and anhydrides of these acids.

[0023] <Release agent> The release agent used in the toner of the present invention is not particularly limited and can be appropriately selected depending on the purpose. Examples of 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.

[0024] 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.

[0025] 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, n-stearyl acrylate-ethyl methacrylate copolymers); and crystalline polymers having long alkyl groups in their side chains can also be used.

[0026] 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.

[0027] 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.

[0028] The melting point of the release agent used in the toner of the present invention 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. When the melting point is 80° C. or higher, heat-resistant storage stability can be ensured, and when the melting point is 100° C. or lower, low-temperature fixability can be ensured.

[0029] The content of the release agent in the toner of the present invention 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, per 100 parts by mass of the total of the binder resin, release agent, and aromatic petroleum resin contained in the toner. When the content of the release agent is 2 parts by mass or more per 100 parts by mass of the total of the binder resin, release agent, and aromatic petroleum resin contained in the toner, sufficient exudation to the surface during fixing is achieved, resulting in good release properties and ensuring low-temperature fixability and high-temperature offset resistance. When the content is 6 parts by mass or less, the amount of release agent precipitated on the toner surface does not increase too much, ensuring the storage stability and fluidity of the toner, preventing deterioration of filming on the electrostatic latent image carrier, etc., and ensuring the transportability of the residual toner.

[0030] <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 the balance between compatibility and incompatibility with polyester resins, styrene resins are preferred. Examples of styrene-based resins 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.

[0031] <<Glass transition temperature (Tg) of aromatic petroleum resins>> 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. When the glass transition temperature is 70° C. or higher, the heat-resistant storage stability of the toner can be ensured, and when it is 90° C. or lower, the low-temperature fixability can be ensured.

[0032] The glass transition temperature (Tg) in the present invention can be measured using, for example, a differential scanning calorimeter (DSC210, manufactured by Seiko Instruments Inc.). Specifically, for example, using a differential scanning calorimeter (DSC210, manufactured by Seiko Instruments Inc.), 0.01 to 0.02 g of a sample is weighed into an aluminum pan and heated to 150°C. The sample is cooled from that temperature to 20°C at a rate of 10°C / min, and then heated at a rate of 10°C / min. The glass transition temperature (Tg) can be 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.

[0033] The content of aromatic petroleum resin in the toner of the present invention is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 7 to 9.5 parts by mass, and more preferably 6 to 8 parts by mass, 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, a decrease in pulverizability when pulverizing the kneaded product of the toner materials can be suppressed and productivity of the pulverized product of the kneaded product of the toner materials can be ensured. When the content is 9.5 parts by mass or less, the low-temperature fixability of the resulting toner can be ensured.

[0034] <Conditions A1 and A2> The toner of the present invention contains toner particles that satisfy the following condition A1. A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle.

[0035] In the present invention, when the cross section of a toner particle is observed, the total area of ​​the release agent domains is 5% or less of the cross section area of ​​the toner particle. If the total area of ​​the release agent domains exceeds 5% of the cross section area of ​​the toner particle, the toner will adhere to the electrostatic latent image carrier when an image is formed by an image forming apparatus, which makes it more likely that filming will occur.

[0036] The toner of the present invention also contains toner particles that satisfy the following condition A2. A2: In the cross section of the toner particle, there is a release agent domain having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less.

[0037]

number

[0038] When only domains of the release agent having an equivalent circular diameter of less than 0.2 μm are present, the proportion of the domains relative to the cross-sectional area of ​​the toner particle is small, making it difficult to obtain the releasing effect of the release agent when fixing an image formed in an image forming apparatus.Furthermore, when only domains of the release agent having an equivalent circular diameter of more than 0.8 μm are present, the toner adheres to the electrostatic latent image carrier during image formation, particularly in a high-temperature, high-humidity environment, and problems such as filming are likely to occur.

[0039] Furthermore, the release agent domains having a diameter equivalent to a perfect circle calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less have a circularity of 0.8 or less as defined by the following formula (1).

[0040]

number

[0041] If the circularity calculated from the above formula (1) of a release agent domain having an equivalent circle diameter of 0.2 μm or more and 0.8 μm or less, calculated from the perimeter of the release agent domain, exceeds 0.8, the release agent domain is likely to be exposed at the toner interface when the kneaded toner material is pulverized.

[0042] <<Method for measuring toner particle cross-sectional area, release agent domain area, perimeter, and circularity>> The area of ​​the release agent domain can be measured by observing the cross section of a toner particle using a transmission electron microscope (TEM), and a scanning transmission electron microscope (STEM) may also be used.

[0043] As the transmission electron microscope (TEM) or scanning transmission electron microscope (STEM), for example, the LEM-2000 model (manufactured by Topcon Corporation) or JEM-2000FX (manufactured by JEOL Ltd.) can be used. More specifically, confirmation is carried out by the following procedure.

[0044] First, toner particles are thoroughly dispersed in a room-temperature curing epoxy resin, and then embedded and the epoxy resin is fully cured. The toner particles are cut using an ultramicrotome (ultrasonic) to extract cross sections of the toner particles, and the cross sections are stained with ruthenium tetroxide or osmium tetroxide, if necessary. Ruthenium tetroxide and osmium tetroxide may be used in combination, if necessary. The cross sections are then observed using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM), and photographed at a magnification of 2000x or more.

[0045] From the obtained cross-sectional image of the toner particle, the cross-sectional area of ​​the toner particle, the area of ​​the release agent domain present in the toner particle, and the perimeter of the release agent domain are calculated. In addition, the areas of all the release agent domains are calculated and summed, and the ratio (%) of the total area of ​​all the release agent domains to the cross-sectional area of ​​the toner particle is calculated.

[0046] In addition, the circularity of all release agent domains whose equivalent circle diameter calculated from the perimeter of the release agent domain is 0.2 μm or more and 0.8 μm or less is calculated using the following formula (1), and the presence or absence of release agent domains whose equivalent circle diameter calculated from the perimeter of the release agent domain is 0.2 μm or more and 0.8 μm or less and whose circularity is 0.8 or less is confirmed in the cross-sectional image of the toner particle.

[0047]

number

[0048] To calculate the cross-sectional area of ​​a toner particle, the area of ​​the release agent domain present within the toner particle, and the perimeter of the release agent domain, an image analysis method such as the texture analysis technique of the image analysis software "Azo-kun" (registered trademark, manufactured by Asahi Kasei Engineering Corporation) can be used. Specifically, for example, multiple images showing multiple cross sections of a toner particle are prepared, and cross-sectional images of 100 toner particles are selected from the images and subjected to image analysis. The image analysis conditions are, for example, the number of textures is set to "3" and the multi-value method is set to "manual." The release agent domain region is separated and recognized from the area of ​​the entire cross section of the toner particle, and the cross-sectional area of ​​each toner particle, the area of ​​the release agent domain present within the toner particle, and the perimeter of the release agent domain are calculated from the region obtained by the separation and recognition. The areas of all the release agent domains are then calculated and summed to determine the ratio (%) of the total area of ​​all the release agent domains to the cross-sectional area of ​​the toner particle.

[0049] 1 is a photograph taken with a scanning transmission electron microscope of the cross section of an example of a toner particle included in a toner according to one embodiment of the present invention and satisfying conditions A1 and A2. In the cross section of the toner particle 12, release agent domains 11 can be seen, each having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm to 0.8 μm, and a circularity of 0.8 or less as defined by the following formula (1):

[0050]

number

[0051] In the toner of the present invention, the content of toner particles that contain a binder resin, a release agent, and an aromatic petroleum resin and that satisfy conditions A1 and A2 is preferably 70% by number or more. When the content of toner particles that satisfy conditions A1 and A2 is 70% by number or more, it is possible to achieve both suppression of filming and good releasability during fixing.

[0052] The content (number %) of toner particles that contain a binder resin, a release agent, and an aromatic petroleum resin and satisfy conditions A1 and A2 can be determined from the ratio of the number of toner particles that contain a binder resin, a release agent, and an aromatic petroleum resin and satisfy conditions A1 and A2 to the number of toner particles that contain a binder resin, a release agent, and an aromatic petroleum resin and whose cross-sectional images are observed.

[0053] <Other ingredients> The toner of the present invention may contain other components in addition to those described above, such as a colorant and external additives.

[0054] <<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), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion, 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, Belcan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bol Daw 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, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake Metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine, Prussian blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green,Anthraquinone green, titanium oxide, zinc oxide, lithopone, and mixtures thereof can be used. The content of the colorant is preferably 0.1 to 80 parts by mass per 100 parts by mass of the binder resin.

[0055] <<External additives>> As the external additives, abrasives, fluidity imparting agents, anti-aggregation agents, conductivity imparting agents, and developability improvers can be used.

[0056] Examples of abrasives that can be used include silica, Teflon (registered trademark) resin powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder, and strontium titanate.

[0057] As the fluidity imparting agent and the anti-aggregation agent, for example, titanium oxide powder, aluminum oxide powder, and resin powder can be used.

[0058] As the conductivity imparting agent, for example, zinc oxide powder, antimony oxide powder, or tin oxide powder can be used.

[0059] As the developing property improver, white fine particles of opposite polarity or black fine particles of opposite polarity may be used.

[0060] These can be used alone or in combination, and can be selected so as to have resistance to development stress such as idle rotation.

[0061] <Toner acid value> By achieving a suitable affinity between the acidic groups in the binder resin and the aromatic petroleum resin during fixing, the aromatic petroleum resin can be present at the domain interface between the binder resin and the release agent particles. The toner of the present invention preferably has an acid value of 6 to 12 mgKOH / g. When the acid value of the toner is 6 to 12 mgKOH / g, the aromatic petroleum resin is not miscible, ensuring the affinity of the aromatic petroleum resin, making it difficult for the release agent particles to exist alone, and making it easier to improve filming on the electrostatic latent image carrier.

[0062] The acid value of the toner can be measured in accordance with the measurement method described in JIS K0070-1992, for example, by the following method.

[0063] [Preparation of sample solution] Add 0.5 g of toner to 120 mL of toluene and dissolve by stirring at room temperature (23°C) for about 10 hours. Add 30 mL of ethanol to make a sample solution.

[0064] The measurement can be calculated using an automatic potentiometric titrator. Specifically, titration is performed with a pre-standardized N / 10 caustic potassium-alcohol solution, and the acid value is calculated using the following formula from the amount of alcoholic potassium solution consumed.

[0065] Acid value = KOH (mL) x N x 56.1 / sample mass (where N is the factor N / 10KOH)

[0066] Specifically, the acid value of the toner can be determined, for example, under the following conditions.

[0067] Measurement device: Potentiometric automatic titrator DL-53 Titrator (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℃ [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 Wait time [s]: 0 Titrant drip 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 end conditions] Maximum dripping amount [mL]: 10.0 Electric potential: No Gradient: No After equivalence point: Yes Number of n: 1 End condition combination: No [Evaluation criteria] Procedure: Standard Potential 1: No Potential 2: No Suspension for reassessment: No

[0068] <Hydroxyl value of toner> The hydroxyl value of the toner of the present invention is preferably 25 to 45 mgKOH / g, and more preferably 30 to 40 mgKOH / g. When the hydroxyl value of the toner is 25 mgKOH / g or more, the fixability between the resin and paper can be ensured, and low-temperature fixability and offset resistance can be ensured. When the hydroxyl value of the toner is 45 mgKOH / g or less, moisture adsorption in a high-temperature and high-humidity environment can be suppressed, the charge amount can be secured, and abnormal images such as background scumming and toner scattering are less likely to occur.

[0069] The hydroxyl value of the toner of the present invention can be measured in accordance with the measurement method described in JIS K0070-1992, for example, by the following method.

[0070] (1) Preparation of 0.5 mol / L potassium hydroxide titration solution Dissolve 40 g of potassium hydroxide in 50 ml of ion-exchanged water. Discard 10 ml of the supernatant of the prepared potassium hydroxide aqueous solution, then add methanol to bring the total volume to 1,000 ml. (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 the color becomes slightly reddish-purple. (3) 5 g of toner is carefully weighed in an Erlenmeyer flask, 5 ml of a mixture of acetic anhydride and pyridine (1:4) is added using a volumetric pipette, and 25 ml of pyridine is added using a measuring cylinder. A condenser is attached to this, and the mixture is reacted in an oil bath at 98°C for 1.5 hours. (4) Add 3 ml of ion-exchanged water from the top of the condenser tube and heat in the oil bath for an additional 10 minutes. (5) Remove the Erlenmeyer flask from the oil bath and allow it to cool to room temperature. Then, rinse the condenser with acetone and remove it. (6) Add 50 ml of tetrahydrofuran using a measuring cylinder, add 10 drops of PP indicator, and titrate with the 0.5 mol / L potassium hydroxide titrant prepared in (1). Near the end point, add 25 ml of the methanol-acetone mixed solution prepared in (2) and continue titration. Determine the titration volume at the point where the slight pink color persists for 30 seconds as the end point. (7) Repeat steps (3) to (6) above without a sample to perform a blank test. (8) Calculate the hydroxyl value using the following formula. Hydroxyl value = [(BA) × f × 28.05 / S] + acid value A: Titration volume of 0.5 mol / L potassium hydroxide titrant required for this test B: Titration volume of 0.5 mol / L potassium hydroxide titrant required for blank test f: Factor of 0.5 mol / L potassium hydroxide titrant ·S: Sample collection amount (g)

[0071] <Average circularity of toner> The average circularity of the toner of the present invention is preferably 0.93 or more and 0.96 or less. When the average circularity of the toner is 0.93 or more, deterioration of the toner transportability and poor fixing can be suppressed, and when the average circularity of the toner is 0.96 or less, poor cleaning of the photosensitive member that is the electrostatic latent image carrier can be suppressed.

[0072] The average circularity of the toner is defined as SR = (perimeter of a circle with the same area as the toner projected area / perimeter of the toner projected image) × 100 (%). It can be measured, for example, using a flow particle image analyzer (FPIA-2100; manufactured by Sysmex Corporation) and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). Specifically, for example, 0.1 to 0.5 ml of 10% by weight surfactant (alkylbenzene sulfonate NEOGEN SC-A; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 ml glass beaker, 0.1 to 0.5 g of toner is added, and the mixture is stirred with a microspatula. Next, 80 ml of ion-exchanged water is added. The resulting dispersion is dispersed for 3 minutes using an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner particles are measured using the FPIA-2100 until a toner concentration of 5,000 to 15,000 particles / μl is obtained. Within this concentration range, it is easy to obtain reproducible measurements of the average circularity in this measurement method.

[0073] (Toner manufacturing method) The method for producing the toner of the present invention includes a kneading step of kneading materials containing a binder resin, an aromatic petroleum resin, and a release agent to obtain a kneaded mixture, and may also include a pulverizing step, a classification step, etc., as necessary.

[0074] The content of the aromatic petroleum resin in the kneaded product is 7% by mass or more and 9.5% by mass or less relative to the total amount of the binder resin, aromatic petroleum resin, and release agent. When the content of the aromatic petroleum resin in the kneaded product is 7% by mass or more relative to the total amount of the binder resin, aromatic petroleum resin, and release agent, a decrease in pulverizability during pulverization of the kneaded product can be suppressed, and when it is 9.5% by mass or less, the low-temperature fixability of the resulting toner can be ensured.

[0075] <Kneading process> In the kneading step, the toner materials, which are a combination of a binder resin, an aromatic petroleum resin, a release agent, and, if necessary, a colorant, a lubricant, and, if necessary, a resin in which a charge control agent, a lubricant, and an additive are uniformly dispersed, can be sufficiently mixed in a mixer, and a kneaded product can be obtained by melting and kneading the mixture using a thermal melt kneader.

[0076] As a mixer used in the production of the toner of the present invention, for example, a Henschel mixer, a super mixer, or the like can be used.

[0077] As the heat melt kneader used in the production of the toner of the present invention, for example, a heating roll, a kneader, or an extruder can be used.

[0078] <Crushing process> The kneaded product obtained in the kneading step is cooled and solidified, and then pulverized to obtain a pulverized product of the kneaded product.

[0079] Methods for pulverizing the kneaded toner material include a jet mill method in which the kneaded toner material is contained in a high-speed airflow, and the kneaded toner material is caused to collide with a collision plate and pulverized using the energy generated; an inter-particle collision method in which particles of the kneaded toner material collide with each other in an airflow; and a mechanical pulverization method in which the kneaded toner material is supplied between a narrow gap and a rotor rotating at high speed and pulverized.

[0080] <Classification process> The pulverized material obtained in the pulverization process can be classified, for example, using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening so as to obtain a predetermined weight average particle size, thereby obtaining toner or toner base particles.

[0081] (developer) The developer according to one embodiment of the present invention may be either a one-component developer or a two-component developer containing the toner of the present invention. The two-component developer contains the toner of the present invention and a carrier. The carrier is not particularly limited and can be appropriately selected depending on the purpose, but a carrier having a core material and a resin layer covering the core material is preferred, and a magnetic carrier in which the core material is a magnetic material is more preferred.

[0082] Examples of magnetic particles used in magnetic carriers include spinel ferrites such as magnetite and gamma iron oxide, spinel ferrites containing one or more metals other than iron (e.g., Mn, Ni, Zn, Mg, Cu), magnetoplumbite ferrites such as barium ferrite, and iron or alloy particles with an oxide layer on their surfaces. Their shape may be granular, spherical, or acicular. Ferromagnetic particles such as iron are preferred when high magnetization is required. Furthermore, considering chemical stability, magnetite, spinel ferrites containing gamma iron oxide, and magnetoplumbite ferrites such as barium ferrite are preferred. Resin carriers with the desired magnetization can be used by selecting the type and content of ferromagnetic particles. The magnetic properties of the carrier are preferably a magnetization strength of 30 to 150 emu / g at 1,000 oersteds.

[0083] Such a resin carrier may be produced by spraying a molten mixture of magnetic fine particles 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 fine particles, and dispersing the magnetic fine particles in a condensation binder.

[0084] Furthermore, the chargeability can be controlled by adhering positively or negatively chargeable particles or conductive particles to the surface of the magnetic carrier, or by coating the surface with a resin.

[0085] As the coating material for the magnetic carrier surface, silicone resin, acrylic resin, epoxy resin, or fluorine-based resin can be used, and the coating can further include positively or negatively charged fine particles or conductive fine particles, but it is preferable to include silicone resin and acrylic resin.

[0086] The mixing ratio of the toner of the present invention and the magnetic carrier is preferably 2 to 10% by mass in terms of toner concentration, and the weight average particle size of the toner is preferably 2 to 10 μm.

[0087] Toner particle size can be measured by various methods. For example, a Coulter Counter Multisizer III (manufactured by Beckman Coulter, Inc.) can be used. The toner to be measured is added to an electrolyte solution containing a surfactant, and the sample is dispersed in an ultrasonic disperser for 1 minute. 50,000 particles are then counted.

[0088] (Toner storage unit) The toner storage unit in the present invention refers to a unit having a function of storing toner and storing the toner. Examples of the toner storage unit include a toner storage container, a developing unit, and a process cartridge.

[0089] The toner container refers to a container that contains toner. The developing unit refers to a unit that contains toner and has a means for developing an image. The process cartridge refers to a unit that integrates at least an electrostatic latent image carrier and a developing means, contains toner, and is detachably mountable to an image forming apparatus. The process cartridge may further include at least one selected from a charging means, an exposure means, and a cleaning means.

[0090] By mounting the toner storage unit of the present invention in an image forming apparatus and forming an image, it is possible to form an image that takes advantage of the characteristics of the toner, which has excellent low-temperature fixability, heat-resistant storage stability, and also excellent image quality.

[0091] FIG. 2 is a schematic view showing an example of a toner storage unit according to an embodiment of the present invention. 2, a process cartridge 110, which is a toner storage unit, has a photosensitive drum 10, a corona charger 58, a developing device 40, a transfer roller 80, and a cleaning device 90. An electrostatic latent image is formed on the photosensitive drum 10 by exposure light L. The image is formed on recording paper 95 by the process cartridge 110 of the present invention.

[0092] (Image forming apparatus and image forming method) 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, transfer means for transferring the toner image developed 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 discharging means, a cleaning means, a recycling means, and a control means, as necessary.

[0093] 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, a transfer step of transferring the toner image developed 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.

[0094] -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 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 forming step can be suitably carried out by an electrostatic latent image forming means.

[0095] The latent image carrier 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.

[0096] Examples of organic photoreceptors include a laminated photoreceptor having a laminated structure in which a 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 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 on a support in which both a charge generation material and a charge transport material are dispersed in a binder resin. In single-layer photoreceptors, a hole transport agent and an electron transport agent can also 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.

[0097] 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.

[0098] The electrostatic latent image forming means preferably has at least a charging means for uniformly charging the surface of the electrostatic latent image bearing member, and an exposure means for imagewise exposing the surface of the electrostatic latent image bearing member to light.

[0099] Charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using a charging means. The charging means is not particularly limited and can be appropriately selected depending on the purpose. Examples 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.

[0100] The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member imagewise using an exposure means. The exposure means is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charging means in the form of an image to be formed, and can be appropriately selected depending on the purpose. Examples of the exposure means 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.

[0101] -Developing process and developing means- The developing step is a step in which the electrostatic latent image formed on the electrostatic latent image carrier is developed using the toner of the present invention. The developing means is a means for developing an electrostatic latent image formed on an electrostatic latent image carrier using the toner of the present invention. The developing step can be suitably carried out by a developing means.

[0102] The toner image can be formed, for example, by developing the electrostatic latent image with the toner of the present invention. The developing means preferably includes at least a developing device that contains toner and can apply the toner to the electrostatic latent image in a contact or non-contact manner, and more preferably 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.

[0103] -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 a transfer means.

[0104] The transfer step is preferably carried out using an intermediate transfer body, whereby 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 of toner, 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.

[0105] 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 onto the recording medium. The number of transfer devices may be one or more. Examples of transfer devices include a corona transfer device that uses corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.

[0106] The recording medium is not particularly limited and can be appropriately selected from known recording media, such as recording paper.

[0107] - 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 a fixing means. 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. Examples of the heating and pressurizing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller and an endless belt.

[0108] -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 eliminating means is a means for applying a charge eliminating bias to the electrostatic latent image bearing member to eliminate the charge. The charge removal step can be suitably carried out by a charge removal means.

[0109] 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.

[0110] -Cleaning process and cleaning means- 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 toner remaining on the electrostatic latent image carrier. The cleaning step can be suitably carried out by a cleaning means.

[0111] The cleaning means is not particularly limited as long as it can remove 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.

[0112] -Recycling process and means- The recycling step is a step in which the toner removed in the cleaning step is recycled 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 examples thereof include known transport means. The recycling step can be suitably carried out by a recycling means.

[0113] -Control process and control means- The control process is a process for controlling each process. The control means is a means for controlling each means. The controlling step may be suitably carried out by a control means. The control means is not particularly limited as long as it can control the movement of each means, and can be appropriately selected depending on the purpose. For example, devices such as a sequencer and a computer can be mentioned.

[0114] (Manufacturing method of printed matter) The method for producing a printed matter of the present invention is a method for producing a printed matter having an image formed on a recording medium using an image forming apparatus including: 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; transfer means for transferring the toner image developed 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 other means may be used as necessary.

[0115] The printed matter produced by the method for producing a printed matter of the present invention has an image formed on a recording medium using the toner of the present invention. The image forming apparatus in the method for producing a printed matter of the present invention can have means similar to the means of the image forming apparatus of the present invention described above, and can form an image on a recording medium in a manner similar to the image forming method of the present invention described above, thereby obtaining a printed matter of the present invention.

[0116] Next, one embodiment of a method for forming an image using the image forming apparatus of the present invention will be described with reference to Fig. 3. Fig. 3 is a schematic diagram showing an example of a portion of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 100A shown in Fig. 3 includes a photosensitive drum 10 as an electrostatic latent image carrier, a charging roller 20 as a charging means, an exposure device as an exposure means, developing units 45K, 45Y, 45M, and 45C as a developing means, an intermediate transfer body 50, a cleaning device 6 having a cleaning blade as a cleaning means, and a discharging lamp 64 as a discharging means. Here, a premix development method may be adopted as the 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 makes it possible to extend the replacement cycle associated with developer deterioration and to eliminate the effort required for developer replacement.

[0117] The intermediate transfer body 50 is an endless belt that is stretched by three rollers 51 arranged inside it and can move in the direction of the arrow. Some of the three rollers 51 also function as transfer bias rollers that can apply a predetermined transfer bias (primary transfer bias) to the intermediate transfer body 50. A cleaning device 90 having a cleaning blade is disposed near the intermediate transfer body 50. Furthermore, a transfer roller 80 is disposed opposite the intermediate transfer body 50 as a transfer means capable of applying a transfer bias for transferring (secondary transfer) the toner image onto the recording paper 95. In this embodiment, an elastic intermediate transfer belt can also be used as the intermediate transfer body 50. As the elastic intermediate transfer belt, for example, one in which a flexible elastic layer is laminated on a rigid base layer that is relatively flexible can be used. In order to prevent the intermediate transfer body 50 from meandering, a guide member for preventing deviation may be provided on the inner peripheral surface of the intermediate transfer body 50 . It is also possible to provide a collecting means for receiving the toner etc. removed by the cleaning device 90. A dish-shaped tray or the like can be used as the collecting means.

[0118] In addition, a corona charger 52 for applying an electric charge to the toner image on the intermediate transfer body 50 is arranged around the intermediate transfer body 50, between the contact point between the photosensitive drum 10 and the intermediate transfer body 50 and the contact point between the intermediate transfer body 50 and the recording paper 95. The developing devices 45K, 45Y, 45M, and 45C for the respective colors of black (K), yellow (Y), magenta (M), and cyan (C) include developer containers 42K, 42Y, 42M, and 42C, a developer supply roller 43, and a developing roller 44. In image forming apparatus 100A, photoconductor drum 10 is uniformly charged by charging roller 20, and then exposure light L is applied to photoconductor drum 10 by an exposure device, forming an electrostatic latent image. Next, the electrostatic latent image formed on photoconductor drum 10 is developed by supplying developers from developing units 45K, 45Y, 45M, and 45C to form a toner image, and the toner image is then transferred (primary transfer) to intermediate transfer member 50 by a transfer bias applied by roller 51. Furthermore, the toner image on intermediate transfer member 50 is charged by corona charger 52 and then transferred (secondary transfer) to recording paper 95. Any toner remaining on photoconductor drum 10 is removed by cleaning device 6, and photoconductor drum 10 is temporarily discharged by discharge lamp 64.

[0119] In FIG. 3, an image is formed by superimposing toner images on an intermediate transfer belt, but the electrophotographic image forming apparatus of the present invention can also be a system in which transfer is performed directly from a transfer drum to a recording medium without using an intermediate transfer belt.

[0120] 4 is a schematic diagram showing an example of an image forming apparatus according to an embodiment of the present invention. Image forming apparatus 100B is a tandem 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. An endless belt-like intermediate transfer member 50 is provided in the center of a copying machine main body 150. The intermediate transfer member 50 is stretched around support rollers 14, 15, and 16, and can rotate in the direction of the arrow. A cleaning device 17 is disposed near the support roller 15 to remove toner remaining on the intermediate transfer body 50. In addition, a tandem developing device 120 is disposed on the intermediate transfer body 50, which is stretched between the support rollers 14 and 15, along the transport direction of the intermediate transfer body 50, and has four image forming means 18 for yellow, cyan, magenta, and black arranged side by side facing each other.

[0121] FIG. 5 is a schematic diagram showing another example of a part of an image forming apparatus according to one embodiment of the present invention. As shown in FIG. 5, the image forming means 18 for each color includes a photosensitive drum 10 as an electrostatic latent image carrier, a charging roller 60 that uniformly charges the photosensitive drum 10, a developing device 70 that develops the electrostatic latent image formed on the photosensitive drum 10 with developers of each color of black (K), yellow (Y), magenta (M) and cyan (C) to form a toner image, a transfer roller 62 that transfers the toner image of each color onto the intermediate transfer body 50, a cleaning device 63, and a de-electrification lamp 64.

[0122] 4, an exposure device is disposed near the tandem developing device 120. The exposure device irradiates exposure light onto photosensitive drums 10K, 10Y, 10M, and 10C, which serve as electrostatic latent image carriers, to form electrostatic latent images. Furthermore, a secondary transfer device 22 is disposed on the opposite side of the intermediate transfer body 50 from the side where the tandem developing device 120 is disposed. The secondary transfer device 22 is made up of a secondary transfer belt 24, which 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 body 50 can come into contact with each other. A fixing device 25 is disposed near the secondary transfer device 22. The fixing device 25 has a fixing belt 26, which is an endless belt, and a pressure roller 27 that is disposed so as to be pressed against the fixing belt 26. Further, near the secondary transfer device 22 and the fixing device 25, there is disposed a reversing device 28 that reverses the recording paper in order to form images on both sides of the recording paper.

[0123] Next, the formation of a full-color image (color copy) in image forming apparatus 100B will be described. First, a document is placed on platen 130 of automatic document feeder (ADF) 400, or ADF 400 is opened and the document is placed on contact glass 32 of scanner 300, and ADF 400 is then closed. Next, when the start switch is pressed, if a document is placed on automatic document feeder (ADF) 400, the document is transported and moved onto contact glass 32. If a document is placed on contact glass 32, scanner 300 is immediately driven, and first and second travelling bodies 33 and 34 travel. At this time, light from a light source is irradiated by first travelling body 33, and light reflected from the document surface is reflected by a mirror on second travelling body 34 and received by reading sensor 36 through imaging lens 35. In this way, a color document containing a color image is read, and image information for each of the colors black, yellow, magenta, and cyan is obtained.

[0124] Furthermore, electrostatic latent images of each color are formed on the photosensitive drums 10K, 10Y, 10M, and 10C by the exposure device based on the image information of each color obtained, and then the electrostatic latent images of each color are developed with developers supplied from the tandem developing devices 120 of each color, forming toner images of each color. The formed toner images of each color are sequentially transferred (primary transfer) onto the intermediate transfer body 50, which is rotated by support rollers 14, 15, and 16, in a superimposed state, and a composite toner image is formed on the intermediate transfer body 50. 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 a paper bank 143, and the recording paper is separated one by one by a separation roller 145 and sent to a paper feed path 146, and then transported by a transport roller 147 and guided to a paper feed path 148 inside the copying machine main body 150, where it is stopped by abutting against a registration roller 49. Alternatively, recording paper on the manual feed tray 54 is fed, separated one by one by a separation roller 58, and placed in the manual feed path 53, where it is stopped by abutting against a registration roller 49. Note that although the registration roller 49 is generally grounded when used, it may also be used with a bias applied to it in order to remove paper dust from the recording paper.

[0125] Then, the registration roller 49 is rotated in time with the composite toner image formed on the intermediate transfer body 50, and the recording paper is sent between the intermediate transfer body 50 and the secondary transfer device 22, and the composite toner image is transferred (secondary transfer) onto the recording paper. The recording paper onto which the composite toner image has been transferred is transported by secondary transfer device 22 and sent to fixing device 25. Then, in fixing device 25, the recording paper is heated and pressed by fixing belt 26 and pressure roller 27, and the composite toner image is fixed onto the recording paper. Thereafter, the recording paper is switched by switching claw 55, discharged by discharge rollers 56, and stacked on paper output tray 57. Alternatively, the recording paper is switched by switching claw 55, reversed by reversing device 28, and guided again to the transfer position, where an image is formed on the back side as well, and then discharged by discharge rollers 56 and stacked on paper output tray 57. Any toner remaining on the intermediate transfer body 50 after the composite toner image has been transferred is removed by the cleaning device 17. [Example]

[0126] 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, "parts" refers to "parts by mass" unless otherwise specified.

[0127] The present invention will be described in more detail below with reference to examples. It should be noted that a person skilled in the art can easily make appropriate changes and modifications to the examples 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.

[0128] Example 1 <Preparation of toner base particles> The following materials were premixed under the following conditions 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.).

[0129] [material] Amorphous polyester resin: 88.5 parts Crystalline polyester resin: 4.5 parts Styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton, Tg value 87°C (catalog value)): 8.0 parts Hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.): 4.0 parts Carbon black (#44, manufactured by Mitsubishi Chemical Corporation): 13 parts

[0130] [Premixing conditions] 1400rpm 1min on 2min off x 5

[0131] 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. The coarsely pulverized kneaded material was then 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 so that the weight average diameter was in the range of 6.8±0.3 μm, to obtain [toner base particles 1].

[0132] Although the glass transition temperature Tg value of styrene-α-methylstyrene copolymer (SA140, manufactured by Kraton), an aromatic petroleum resin, is listed as 87°C in the catalog, variations occur within a range of approximately ±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.

[0133] <Method for measuring the glass transition temperature (Tg) of styrene-α-methylstyrene copolymer> Approximately 5.0 mg of the target sample, styrene-α-methylstyrene copolymer (SA140, Kraton) 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. The glass transition temperature (Tg) of the styrene-α-methylstyrene copolymer was determined from the resulting DSC curve using the analysis program in the differential scanning calorimeter. The glass transition temperature (Tg) of the styrene-α-methylstyrene copolymer was determined to be 81°C.

[0134] <Preparation of Toner Developer> To 100 parts by mass of the obtained toner base particles, 1 part by mass of metal oxide fine particles (HDK-2000 Clariant) was added as an external additive, and the mixture was stirred and mixed in a Henschel mixer to prepare a toner treated with an external additive.

[0135] 5% by mass 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].

[0136] <Method for measuring the area, perimeter and circularity of the release agent domain> The cross section of the [toner base particle 1] was observed using a transmission electron microscope to measure the area and perimeter of the release agent domain present in the [toner base particle 1], and the circularity of the release agent domain was determined.

[0137] First, particles of [toner base particle 1] were thoroughly dispersed in a room-temperature curing epoxy resin, and then the toner particles were embedded in the epoxy resin. The epoxy resin was then fully cured. Subsequently, a cross-section of [toner base particle 1] was prepared using an ultramicrotome (ultrasonic) and, if necessary, stained using a combination of ruthenium tetroxide and osmium tetroxide. This was then observed using a scanning transmission electron microscope (STEM) (LEM-2000 (manufactured by Topcon Corporation) or JEM-2000FX (manufactured by JEOL Ltd.)) at 2000x magnification to obtain a cross-sectional image of [toner base particle 1]. From the obtained cross-sectional image of [toner base particle 1], the cross-sectional area of ​​the toner particle of [toner base particle 1], the area of ​​the release agent domain present in the cross-section of the toner particle of [toner base particle 1], and the perimeter of the release agent domain were determined.

[0138] The cross-sectional area of ​​the toner particle [Toner Base Particle 1], the area of ​​the release agent domain present in the cross-section of the toner particle, and the perimeter of the release agent domain were calculated using an image analysis method using the texture analysis technique of the image analysis software "Azokun" (registered trademark, manufactured by Asahi Kasei Engineering Corporation). Specifically, multiple images of the cross-sections of the toner particle [Toner Base Particle 1] were prepared, and cross-sectional images of 100 toner particles were selected from the images and analyzed. The image analysis conditions were: texture number "3" and multi-thresholding method "manual." The release agent domain region was separated and recognized from the entire cross-sectional area of ​​the toner particle [Toner Base Particle 1]. The cross-sectional area of ​​each toner particle, the area of ​​the release agent domain present in the cross-section of the particle [Toner Base Particle 1], and the perimeter of the release agent domain were calculated from the region obtained by the separation and recognition. The areas of all the release agent domains were calculated and summed to determine the ratio (%) of the total area of ​​all the release agent domains to the cross-sectional area of ​​the toner particle. The results are shown in Table 1.

[0139] Furthermore, when the circularity of all release agent domains in which the equivalent circle diameter calculated from the perimeter of the release agent domain is 0.2 μm or more and 0.8 μm or less was calculated using the following formula (1), it was found that there were release agent domains in which the circularity was 0.8 or less in the cross-sectional images of multiple toner particles. Figure 1 shows one of the cross sections of a toner particle containing a release agent domain in which the equivalent circle diameter calculated from the perimeter of the release agent domain is 0.2 μm or more and 0.8 μm or less and the circularity calculated from the following formula (1) is 0.8 or less.

[0140]

number

[0141] The above results show that the [Toner Base Particles 1] have particles that satisfy the following conditions A1 and A2.

[0142] (conditions) A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle. A2: In the cross section of the toner particle, there is a release agent domain having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less.

[0143]

number

[0144] [Evaluation of low-temperature fixability] The obtained [Toner Developer 1] was placed in a copier (RICOH IM C5510) manufactured by Ricoh Co., Ltd., and an image was output. The toner adhesion amount was 0.4 mg / cm. 2A solid image of this type was formed on a recording medium, paper (Ricoh Co., Ltd., Type 6200), through an exposure process, a development process, and a transfer process. The fixing linear speed was 256 mm / sec. The fixing temperature was output in 2°C increments, the lowest temperature at which cold offset did not occur was measured, and the low-temperature fixability was evaluated based on the following evaluation criteria. The lowest temperature at which cold offset did not occur is the lowest fixing temperature. The results are shown in Table 2. "A" to "C" were judged to be sufficient for practical use.

[0145] -Evaluation criteria for low-temperature fixability- A: Less than 120℃ B: 120℃ or higher but lower than 125℃ C: 125℃ or higher and lower than 130℃ D: 130℃ or more

[0146] [Hot offset resistance] The obtained [toner developer 1] was placed in the storage unit of a copier (RICOH MPC 6003, manufactured by Ricoh Co., Ltd.) and the toner adhesion amount was adjusted to 0.4 mg / cm 2 A solid image was formed on a recording medium, paper (Type 6200, manufactured by Ricoh Co., Ltd.) so that the image was as follows: The fixing linear speed was set to 256 mm / sec, the NIP width of the fixing device was set to 11 mm, and the fixing temperature was set to 5°C increments. The maximum temperature at which hot offset did not occur was measured, and the hot offset resistance was evaluated based on the following evaluation criteria. The maximum temperature at which hot offset did not occur was the maximum fixing temperature. The results are shown in Table 2. "A" to "C" were judged to be sufficient for practical use.

[0147] [Evaluation criteria] A: The upper limit of the fixing temperature is 200°C or higher B: Upper limit fixing temperature is 190℃ or more and less than 200℃ C: Upper limit fixing temperature is 180℃ or more and less than 190℃ D: Upper limit fixing temperature is less than 180°C

[0148] [HH Filming Rating] The obtained [Toner Developer 1] was placed in a Ricoh Co., Ltd. copier (RICOH IM 9000) and run for 200,000 sheets at an image area ratio of 1.0% in a high temperature and high humidity environment (30°C, 90%). After that, the state of filming on the photoreceptor, which is the electrostatic latent image carrier, was visually observed and the filming was evaluated based on the following evaluation criteria. The results are shown in Table 2. "A" to "C" were judged to be sufficient for practical use.

[0149] -Filming evaluation criteria- A: No toner residue can be found on the photosensitive drum. B: Minute toner deposits can be seen on some parts of the photosensitive drum, but there is no effect on the image. C: A large amount of toner deposits can be seen on the photoconductor, but there is no effect on the image. D: A large amount of toner was found on the photoconductor, causing image abnormalities.

[0150] [MM Filming Rating] The obtained [toner developer 1] was placed in a Ricoh Co., Ltd. copier (RICOH IM C9000) and run at a high temperature and high humidity environment (23°C, 50%) with 200,000 sheets printed at an image area ratio of 1.0%, after which the state of filming on the photoreceptor, which is the electrostatic latent image carrier, was visually observed and evaluated based on the following evaluation criteria. The results are shown in Table 2. "A" to "C" were judged to be sufficient for practical use.

[0151] -Filming evaluation criteria- A: No toner residue can be found on the photosensitive drum. B: Minute toner deposits can be seen on some parts of the photosensitive drum, but there is no effect on the image. C: A large amount of toner deposits can be seen on the photoconductor, but there is no effect on the image. D: A large amount of toner was found on the photoconductor, causing image abnormalities.

[0152] Example 2 [Toner base particles 2] and [Toner developer 2] were prepared in the same manner as in Example 1, and the same measurements and evaluations were carried out, except that the temperature of the twin-screw kneader was changed from 120°C to 130°C, the premixing 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. The results are shown in Tables 1 and 2. In [Toner base particles 2], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0153] Example 3 [Toner base particles 3] and [Toner developer 3] were prepared in the same manner as in Example 1, and the same measurements and evaluations were carried out, except that the temperature of the twin-screw kneader was changed from 120°C to 105°C, the premixing 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. The results are shown in Tables 1 and 2. In [Toner base particles 3], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0154] Example 4 [Toner base particles 4] and [Toner developer 4] were prepared in the same manner as in Example 1, and measurements and evaluations were carried out in the same manner as in Example 1, except that the premixing conditions were changed to 1400 rpm, 1 min on, 2 min off x 5, and the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 4.0 parts to 2.5 parts. The results are shown in Tables 1 and 2. Note that for [Toner base particles 4], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0155] Example 5 [Toner base particles 5] and [Toner developer 5] were prepared in the same manner as in Example 1, except that the premixing conditions were changed to 1400 rpm, 1 min on, 2 min off x 5, and the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 4.0 parts to 5.5 parts in Example 1, and the same measurements and evaluations were carried out. The results are shown in Tables 1 and 2. In [Toner base particles 5], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0156] Example 6 [Toner base particles 6] and [Toner developer 6] were prepared in the same manner as in Example 1, except that the premixing conditions were changed to 1200 rpm, 1 minute on, 2 minutes off x 4, and the same measurements and evaluations were carried out. The results are shown in Tables 1 and 2. In [Toner base particles 6], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0157] Example 7 [Toner base particles 7] and [Toner developer 7] were prepared in the same manner as in Example 1, except that the premixing conditions were changed to 1000 rpm, 1 minute on, 2 minutes off x 3, and the same measurements and evaluations were carried out. The results are shown in Tables 1 and 2. In [Toner base particles 7], particles satisfying the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0158] Example 8 [Toner base particles 8] and [Toner developer 8] were prepared in the same manner as in Example 1, except that the wax type was changed from a hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) to a rice brown wax (300VITA, manufactured by Clariant), and the same measurements and evaluations were carried out. The results are shown in Tables 1 and 2. In [Toner base particles 8], particles that satisfied the above conditions A1 and A2 were present among 100 particles selected for image analysis of particle cross sections.

[0159] (Comparative Example 1) [Toner base particles 9] and [Toner developer 9] were prepared in the same manner as in Example 1, and the same measurements and evaluations were carried out, except that the temperature of the twin-screw kneader was changed from 120°C to 140°C, the premixing 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 4.0 parts. The results are shown in Tables 1 and 2. Note that for [Toner base particles 9], none of the 100 particles selected for image analysis of particle cross sections satisfied the above conditions A1 and A2.

[0160] (Comparative Example 2) [Toner base particles 10] and [Toner developer 10] were prepared in the same manner as in Example 1, and the same measurements and evaluations were carried out, except that the temperature of the twin-screw kneader was changed from 120°C to 100°C, the premixing 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 12.0 parts. The results are shown in Tables 1 and 2. Note that for [Toner base particles 10], none of the 100 particles selected for image analysis of particle cross sections satisfied the above conditions A1 and A2.

[0161] (Comparative Example 3) [Toner base particles 11] and [Toner developer 11] were prepared in the same manner as in Example 1, except that the premixing conditions were changed to 1400 rpm, 1 min on, 2 min off x 5, and the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 4.0 parts to 2.0 parts in Example 1, and the same measurements and evaluations were carried out. The results are shown in Tables 1 and 2. Note that for [Toner base particles 11], among the 100 particles selected for image analysis of particle cross sections, no particles fulfilled the above conditions A1 and A2.

[0162] Comparative Example 4 [Toner base particles 12] and [Toner developer 12] were prepared in the same manner as in Example 1, and measurements and evaluations were carried out in the same manner as in Example 1, except that the premixing conditions were changed to 1400 rpm, 1 min on, 2 min off x 5, and the amount of hydrocarbon wax (FNP-0090, manufactured by Nippon Seiro Co., Ltd.) was changed from 4.0 parts to 6.0 parts. The results are shown in Tables 1 and 2. Note that for [Toner base particles 12], none of the 100 particles selected for image analysis of particle cross sections satisfied the above conditions A1 and A2.

[0163] [Table 1]

[0164] [Table 2]

[0165] From the above, it has been shown that the toner satisfying the constitution of the present invention has excellent low-temperature fixing properties, and can simultaneously suppress filming in a high-temperature, high-humidity environment and provide good releasability during fixing.

[0166] The present invention includes, for example, the following aspects. <1> A toner comprising a binder resin, a release agent, and an aromatic petroleum resin, A toner comprising toner particles that satisfy the following conditions A1 and A2. A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle. A2: In the cross section of the toner particle, there is a release agent domain having a true circle equivalent diameter calculated from the perimeter of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less.

number

[0167] the above <1> from <6> Any of the above toners <7> the toner storage unit, <8> The image forming apparatus <9> The image forming method of <10> The method for producing the printed matter <11> According to this toner manufacturing method, the various problems encountered in the prior art can be solved and the object of the present invention can be achieved. [Explanation of symbols]

[0168] 6, 17, 63 Cleaning device 10, 10K, 10Y, 10M, 10C photoconductor drum 11 Release Agent Domain 12 Toner particles 14, 15, 16 Support rollers 18 Image forming means 20, 60 charging roller 22 Secondary transfer device 23, 51 Laura 24 Secondary transfer belt 40 Developer 42K, 42Y, 42M, 42C Developer storage compartment 43 Developer supply roller 44 Developing roller 45K, 45Y, 45M, 45C, 70 Developer 50 Intermediate transfer body 52 Corona charger 58 Corona charger 62 Transfer roller 64 Static elimination lamp 80 Transfer roller 90 Cleaning Device 95 Recording Paper 100A, 100B Image forming apparatus 110 Process cartridge 120 Tandem developing unit 150 Copying device body 200 Paper feed table 300 scanner 400 Automatic Document Feeder (ADF) L exposure light [Prior art documents] [Patent documents]

[0169] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-62599 [Patent Document 2] Japanese Patent Publication No. 2021-144186 [Patent Document 3] Japanese Patent Application Publication No. 2023-047237

Claims

1. A toner comprising a binder resin, a release agent, and an aromatic petroleum resin, A toner comprising toner particles that satisfy the following conditions A1 and A2. A1: The total area of ​​the release agent domains in the cross section of the toner particle is 5% or less of the area of ​​the cross section of the toner particle. A2: In the cross section of the toner particle, there is present a release agent domain having a true circle equivalent diameter calculated from the circumferential length of the release agent domain of 0.2 μm or more and 0.8 μm or less, and a circularity defined by the following formula (1) of 0.8 or less. [Equation 1]

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

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

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

5. 3. The toner according to claim 1, wherein the content of the toner particles is 70% by number or more.

6. 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 relative to 100 parts by mass of the total amount of the binder resin, the release agent, and the aromatic petroleum resin.

7. A toner storage unit that stores the toner according to claim 1 or 2.

8. 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 claim 1; a transfer means for transferring the toner image developed on the electrostatic latent image carrier onto the surface of a recording medium; a fixing unit for fixing the toner image transferred onto the surface of the recording medium.

9. 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 claim 1 or 2; a transfer step of transferring the toner image developed 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.

10. 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 claim 1; a transfer means for transferring the toner image developed on the electrostatic latent image carrier onto the surface of a recording medium; a fixing unit that fixes the toner image transferred onto the surface of the recording medium, to produce a printed matter having an image formed on the recording medium.

11. a kneading step of kneading materials containing a binder resin, an aromatic petroleum resin, and a release agent to obtain a kneaded product, 3. The toner manufacturing method according to claim 1, wherein a content of the aromatic petroleum resin in the kneaded mixture is 7 parts by mass or more and 9.5 parts by mass or less, relative to 100 parts by mass of a total amount of the binder resin, the release agent, and the aromatic petroleum resin.

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