JP7794063B2 - Toner, image forming apparatus, image forming method, and method for manufacturing printed matter - Google Patents

Description

The present invention relates to a toner, an image forming apparatus, an image forming method, and a method for producing printed matter.

In recent years, pulverized toners have been required to have excellent pulverizability due to environmental considerations. To improve pulverizability, not only improvements in the manufacturing process but also in the materials are required.
Furthermore, in addition to the conventional energy saving, it is important to improve low-temperature fixability in order to suppress volatile fine particle components, and it is particularly necessary to ensure heat-resistant storage stability and durability in actual machines.
As described above, it is necessary for pulverized toner technology to achieve high levels of pulverizability, low-temperature fixability, heat-resistant storage stability, and durability.

For example, Patent Documents 1, 2 and 4 disclose that a low molecular weight thermoplastic resin is used and the thermal properties of the binder resin are controlled to achieve both grindability and low temperature fixability.
Furthermore, in Patent Document 3, it is said that low-temperature fixability and heat-resistant storage stability are both achieved by using a hydrogenated petroleum resin.
Furthermore, Patent Document 5 states that a core-shell toner achieves both low-temperature fixability and heat-resistant storage stability.
As another document relating to pulverized toner, Patent Document 6 discloses that low-temperature fixability and heat-resistant storage stability are improved by using a styrene resin having certain specific physical properties.

The object of the present invention is to provide a toner that combines high levels of grindability, low-temperature fixability, heat resistance, and durability.

The above problem is solved by the following configuration 1).
1) A toner containing at least a non-crystalline polyester resin, a crystalline polyester resin, a wax, and an aromatic petroleum resin,
The SP value of the wax is 8.0 or more and 8.5 or less,
The melting point of the wax is 80°C or higher and 100°C or lower, and the ratio of the crystalline polyester resin to the aromatic petroleum resin is 1.0 or higher and 1.2 or lower in mass ratio,
the aromatic petroleum resin is a copolymer of styrene or α-methylstyrene,
The toner is characterized in that the amorphous polyester resin contains at least bisphenol A and ethylene glycol as diol components .

The present invention makes it possible to provide a toner that combines high levels of grindability, low-temperature fixability, heat resistance, and durability.

1 is a diagram illustrating an embodiment of an image forming apparatus according to the present invention; FIG. 10 is a diagram illustrating another embodiment of the image forming apparatus of the present invention. FIG. 10 is a diagram illustrating another embodiment of the image forming apparatus of the present invention. FIG. 2 is a diagram illustrating an image forming unit.

The present invention will be described in detail below.
(Toner composition)
The toner of the present invention contains at least a non-crystalline polyester resin, a crystalline polyester resin, a wax, and an aromatic petroleum resin. By containing these materials and satisfying the composition and physical properties described below, it is possible to provide a toner that can simultaneously achieve high levels of grindability, low-temperature fixability, heat resistance, and durability.

(amorphous polyester resin)
The amorphous polyester resin used in the toner of the present invention is not particularly limited, and known ones can be used. In particular, it is preferable that the diol component contains at least bisphenol A and ethylene glycol. By including bisphenol A as the diol component, the toner can ensure good heat resistance. Furthermore, by including ethylene glycol as the diol component, the toner can maintain good dispersibility with waxes having low SP values. As a result, the durability of the toner can be improved.

The proportion of bisphenol A and ethylene glycol in the diol component of the amorphous polyester resin is preferably 70 to 100% by mass. Furthermore, the ratio (mol %) of bisphenol A to ethylene glycol is preferably 50:50 to 90:10.

Other than bisphenol A and ethylene glycol, the following monomers may be used to form the amorphous polyester.
Examples of the dihydric alcohol component include propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and diols obtained by polymerizing bisphenol A with a cyclic ether such as ethylene oxide or propylene oxide.

Trihydric or higher alcohols can also be used in combination as a means of crosslinking the polyester resin. Examples of trihydric or higher polyhydric alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol (e.g., dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxybenzene.

Examples of the acid component that forms the amorphous polyester include benzenedicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, or their anhydrides; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or their anhydrides; unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid, and mesaconic acid; and unsaturated dibasic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, and alkenylsuccinic anhydride.

Furthermore, examples of trivalent or higher polyvalent carboxylic acid components include trimellitic acid, pyromellic acid, 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-dicarboxy-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxy)methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, or anhydrides or partial lower alkyl esters thereof.

The acid value of the amorphous polyester is preferably 0.1 mgKOH/g to 100 mgKOH/g, more preferably 0.1 mgKOH/g to 70 mgKOH/g, and most preferably 0.1 mgKOH/g to 50 mgKOH/g.

In the present invention, the molecular weight distribution of the binder resin is measured by gel permeation chromatography (GPC) using THF as a solvent.

The content of the amorphous polyester resin in the toner is preferably 60% by mass or more and 90% by mass or less.

(Crystalline polyester resin)
The toner of the present invention contains a crystalline polyester resin, which has the effect of ensuring good low-temperature fixability.
The melting point of the crystalline polyester resin is preferably 100°C or higher and 120°C or lower. Crystalline polyesters have some uncrystallized portions, and their glass transition temperatures increase depending on the melting point. Furthermore, the closer the glass transition temperature of the uncrystallized portions is to the glass transition temperature of the amorphous polyester resin, the higher the compatibility and the higher the low-temperature fixability. For these reasons, the melting point of the crystalline polyester resin is preferably 100°C or higher. However, if the melting point of the crystalline polyester resin is too high, melting due to the heat during fixation will be insufficient, which will also result in impaired low-temperature fixability. For these reasons, the melting point of the crystalline polyester resin is preferably 120°C or lower.

The crystalline polyester resin can be produced by conventional polycondensation of (I) a polycarboxylic acid component consisting of a linear unsaturated aliphatic dicarboxylic acid or its reactive derivative (such as an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, or an acid halide) with (II) a polyhydric alcohol component consisting of a linear aliphatic diol. In this case, a small amount of other polycarboxylic acid can be added to the polycarboxylic acid component, if necessary. Examples of polycarboxylic acids include (i) unsaturated aliphatic dicarboxylic acids having branched chains, (ii) saturated aliphatic polycarboxylic acids such as saturated aliphatic dicarboxylic acids and saturated aliphatic tricarboxylic acids, and (iii) aromatic polycarboxylic acids such as aromatic dicarboxylic acids and aromatic tricarboxylic acids. The amount of these polycarboxylic acids added is typically 30 mol % or less, preferably 10 mol % or less, based on the total carboxylic acids. The amount is adjusted to a range in which the resulting polyester is crystalline.

Specific examples of polycarboxylic acids that can be added as needed include dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, and terephthalic acid; and tricarboxylic or higher polycarboxylic acids such as trimellitic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, and 1,2,7,8-octanetetracarboxylic acid.

If necessary, small amounts of aliphatic branched dihydric alcohols, cyclic dihydric alcohols, and trihydric or higher polyhydric alcohols can be added to the polyhydric alcohol component. The amount added is 30 mol % or less, preferably 10 mol % or less, based on the total alcohol content, and is added appropriately within a range that allows the resulting polyester to be crystalline. Examples of polyhydric alcohols that can be added as needed include 1,4-bis(hydroxymethyl)cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, and glycerin.

The crystalline polyester resin preferably has a sharp molecular weight distribution from the viewpoint of low-temperature fixability, and the molecular weight is preferably relatively low. The molecular weight of the crystalline polyester resin is preferably such that, in the molecular weight distribution by GPC of its o-dichlorobenzene soluble portion, the weight average molecular weight (Mw) is 5,500 to 6,500, the number average molecular weight (Mn) is 1,300 to 1,500, and the Mw/Mn ratio is 2 to 5.
The molecular weight distribution of the crystalline polyester resin is based on a molecular weight distribution chart in which the horizontal axis is log M (M is molecular weight) and the vertical axis is mass %.

In the case of the crystalline polyester resin used in the present invention, it is preferable that the molecular weight distribution diagram has a molecular weight peak in the range of 3.5 to 4.0 (mass%), and that the half-value width of the peak is 1.5 or less.

The content of the crystalline polyester resin in the toner is preferably 5.0% by mass or less. By keeping the content at 5.0% by mass or less, adhesion to the photoreceptor due to recrystallization after toner formation can be suppressed, making it possible to prevent image blurring.

More preferably, the content of the crystalline polyester resin in the toner is 2.5% by mass or more and 5.0% by mass or less.

(wax)
The toner of the present invention contains a wax, and it is particularly preferred that the SP value is 8.0 or more and 8.5 or less and the melting point is 80°C or more and 100°C or less.
By having a wax SP value of 8.0 or more, it is possible to maintain good dispersion of the aromatic petroleum resin (described below), making it possible to achieve high levels of both grindability and low-temperature fixability without causing fixing inhibition. Furthermore, by having a wax SP value of 8.5 or less, it is possible to prevent compatibility with the aromatic petroleum resin. As a result, it is possible to achieve a state in which a certain amount of aromatic petroleum resin is dispersed within the toner, making it possible to ensure good grindability even when a certain amount of crystalline polyester is used.

By having a wax melting point of 80°C or higher, the thermal properties can be made similar to those of aromatic petroleum resins and crystalline polyesters. As a result, these materials can be plasticized when heated, ensuring good low-temperature fixability. Furthermore, by having a wax melting point of 100°C or lower, poor release properties due to insufficient wax melting when heated can be prevented, again ensuring good low-temperature fixability.

Any known wax can be used as long as it maintains the SP value and melting point within the above levels. Examples include Fischer-Tropsch wax and microcrystalline wax, with Fischer-Tropsch wax being particularly preferred. Fischer-Tropsch wax has a high melting point and a sharp molecular weight distribution, giving it excellent heat resistance and durability.

The amount of wax added to the toner is preferably 2.5% by mass or more and 6.5% by mass or less, and particularly preferably 3.5% by mass or more and 5.5% by mass or less. By adding wax in an amount of 3.5% by mass or more and 5.5% by mass or less, it is possible to ensure releasability while preventing deterioration of durability due to excess wax.

The melting point of the wax can be measured by the following method.
The glass transition temperature and melting point were measured under the following conditions using a thermal analysis workstation TA-60WS and a differential scanning calorimeter DSC-60 (manufactured by Shimadzu Corporation).
Sample container: Aluminum sample pan (with lid)
Sample amount: 5 mg
Reference: Aluminum sample pan (alumina 10 mg)
Atmosphere: Nitrogen (flow rate 50 ml/min)
Temperature increase and decrease conditions: as follows: Starting temperature: 20°C
Temperature increase rate: 10°C/min
End temperature: 150℃
Holding time: None Temperature decreasing rate: 10°C/min
End temperature: 20℃
Holding time: None Heating rate: 10°C/min
(The endothermic peak observed during this temperature rise process was taken as the melting point.)
End temperature: 150℃

(Aromatic petroleum resin)
The toner of the present invention contains an aromatic petroleum resin, which improves grindability and makes it possible to improve heat resistance while maintaining low-temperature fixability.
The aromatic petroleum resin is a resin synthesized using petroleum C9 fractions such as styrene, vinyltoluene, indene, etc. In particular, styrene copolymers of styrene or α-methylstyrene are preferred.
The weight-average molecular weight (Mw) of the aromatic petroleum resin is preferably 2000 or more and 3500 or less. By having a weight-average molecular weight of 2000 or more, durability in an actual machine can be ensured. Furthermore, by having a weight-average molecular weight of 3500 or less, good grindability can be ensured.

The styrene copolymer is not particularly limited, but examples include polymers of styrene and its substitution products, such as polystyrene, poly-p-styrene, and polyvinyltoluene; styrene-α-methylstyrene copolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer. Among these, styrene-α-methylstyrene copolymer is particularly preferred.

The glass transition temperature (Tg) of the styrene copolymer is preferably 60°C or higher, and more preferably 65 to 85°C. Having a Tg of 60°C or higher improves heat-resistant storage stability.

Tg is measured using a differential scanning calorimeter (Q-200, manufactured by TA Instruments). Specifically, approximately 5.0 mg of the target sample is placed in an aluminum sample container, which is then placed on a holder unit and set in an electric furnace. The sample is then heated from -80°C to 150°C at a rate of 10°C/min in a nitrogen atmosphere, and the glass transition temperature (Tg) of the target sample is determined from the resulting DSC curve using the analysis program in the differential scanning calorimeter.

In the toner of the present invention, the ratio of the crystalline polyester to the aromatic petroleum resin is preferably 1.0 or more and 1.2 or less by mass. The aromatic petroleum resin used in the present invention disperses within the toner to improve grindability, but because it has a glass transition temperature above a certain level, it acts to impair low-temperature fixability. On the other hand, the crystalline polyester resin improves low-temperature fixability, but the crystallized portion acts to impair grindability. In other words, the aromatic petroleum resin and crystalline polyester resin used in the present invention have opposing effects on grindability and low-temperature fixability. To properly utilize the effects of both materials, it is important to ensure that the proportions of both materials in the toner are approximately the same. Generally, crystalline polyester is partially miscible with amorphous polyester, so the proportion of the crystallized portion is slightly less than the amount added in the toner. As a result of the above considerations and investigations, it is possible to achieve high levels of both grindability and low-temperature fixability by setting the ratio of crystalline polyester to aromatic petroleum resin in the range of 1.0 or more and 1.2 or less.

In the toner of the present invention, it is preferable that the content of aromatic petroleum resin is 3.0% by mass or more. By setting the content to 3.0% by mass or more, it is possible to maintain a certain level of grindability while also improving wax dispersibility, thereby improving durability.

More preferably, the content of the aromatic petroleum resin in the toner is 3.5% by mass or more and 5.0% by mass or less.

(coloring agent)
The toner of the present invention may contain a colorant.
As the colorant, all known dyes and pigments can be used, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion lead, 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, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K , Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue Examples of the colorant include 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. The content of the colorant is preferably 1 to 15% by mass, and more preferably 3 to 10% by mass, based on the toner.

The colorant used in the present invention can also be used as a masterbatch composited with a resin. The binder resin kneaded with the masterbatch can be the same as the binder resin described above. The binder resin may be used alone or in combination with two or more types.

The masterbatch can be obtained by mixing and kneading the resin and colorant used to prepare the masterbatch under high shear force. An organic solvent can be used to enhance the interaction between the colorant and resin. The so-called flushing method, in which an aqueous paste of the colorant containing water is mixed and kneaded with the resin and organic solvent, the colorant is transferred to the resin, and the water and organic solvent components are removed, is also suitable because the wet cake of the colorant can be used as is, eliminating the need for drying. A high-shear dispersing device such as a three-roll mill is preferably used for mixing and kneading. The amount of the masterbatch used is preferably 0.1 to 20 parts by mass per 100 parts by mass of binder resin.

The resin used to prepare the masterbatch preferably has an acid value of 30 mgKOH/g or less and an amine value of 1 to 100, and is used with a colorant dispersed therein. It is more preferable that the resin has an acid value of 20 mgKOH/g or less and an amine value of 10 to 50, and is used with a colorant dispersed therein. An acid value of 30 mgKOH/g or less ensures appropriate charging properties under high humidity conditions and sufficient pigment dispersibility. An amine value of 1 or more and an amine value of 100 or less ensures sufficient pigment dispersibility. The acid value can be measured using the method specified in JIS K0070, and the amine value can be measured using the method specified in JIS K7237.

A dispersant can be used to improve the dispersibility of the pigment. From the viewpoint of pigment dispersibility, the dispersant preferably has high compatibility with the binder resin. Specific commercially available products include "Ajisper PB821" and "Ajisper PB822" (manufactured by Ajinomoto Fine-Techno Co., Ltd.), "Disperbyk-2001" (manufactured by BYK-Chemie), and "EFKA-4010" (manufactured by EFKA).
The mass average molecular weight of the dispersant, as determined by gel permeation chromatography using a styrene-equivalent mass spectrum, is preferably 500 to 100,000, and from the viewpoint of pigment dispersibility, more preferably 3,000 to 100,000. In particular, 5,000 to 50,000 is preferred, and 5,000 to 30,000 is most preferred. A molecular weight of 500 or more ensures appropriate polarity and improved colorant dispersibility. A molecular weight of 100,000 or less ensures appropriate affinity with the solvent and improved colorant dispersibility. The dispersant is preferably blended in the toner at a ratio of 0.1 to 10% by mass relative to the colorant. A blending ratio of 0.1% by mass or more ensures sufficient pigment dispersibility, while a blending ratio of 10% by mass or less prevents a decrease in chargeability under high humidity conditions.

(Charge control agent)
The toner of the present invention may contain a charge control agent as needed. Any known charge control agent can be used. However, for color toners, white or light-colored ones are preferred. Colored charge control agents tend to mix with the toner, making it dull, so the content must be kept low.

Examples of charge control agents include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus elements or compounds, tungsten elements or compounds, fluorine-based activators, metal salicylate salts, and metal salts of salicylic acid derivatives.

Specifically, these include the nigrosine dye Bontron 03, the quaternary ammonium salt Bontron P-51, the metal-containing azo dye Bontron S-34, the oxynaphthoic acid metal complex E-82, the salicylic acid metal complex E-84, and the phenol condensate E-89 (all manufactured by Orient Chemical Industry Co., Ltd.), the quaternary ammonium salt molybdenum complexes TP-302 and TP-415 (both manufactured by Hodogaya Chemical Co., Ltd.), the quaternary ammonium salt Copy Charge PSY VP2038, the triphenylmethane derivative Copy Blue PR, and the quaternary ammonium salt Copy Charge NEG VP2036 and Copy Charge NX. Examples include VP434 (all manufactured by Hoechst), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymeric compounds with functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

In the present invention, the amount of charge control agent used is determined by the type of binder resin, the presence or absence of optional additives, and the toner manufacturing method, including the dispersion method, and is not uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight per 100 parts by weight of binder resin. A range of 0.2 to 5 parts by weight is preferable. By keeping the blending ratio at 10 parts by weight or less, the toner's chargeability is appropriate, the effect of the main charge control agent can be improved, the electrostatic attraction force with the developing roller is appropriate, and a decrease in developer fluidity and a decrease in image density can be prevented. These charge control agents and release agents can be melt-kneaded with the masterbatch and resin.

(external additives)
Furthermore, to improve the fluidity, storage stability, developability, transferability, and durability of the toner, inorganic fine particles such as oxide fine particles and hydrophobic silica fine powder, or polymeric resin fine particles may be added and mixed with the toner base particles as external additives. This effect is achieved by covering wax, which reduces transferability and durability, with these external additives, and by covering the toner surface with the fine particles, thereby reducing the contact area. It is preferable that the surfaces of these inorganic fine particles are hydrophobized, and metal oxide fine particles such as hydrophobized silica or titanium oxide are preferably used. By adding a larger amount of hydrophobized titanium oxide than the amount of hydrophobized silica, the toner can be made more stable against humidity, improving the toner transfer rate and providing good filming resistance.

The inorganic particles and resin particles preferably have a primary particle diameter of 5 nm to 2 μm. The proportion of inorganic particles used varies depending on the type, but is typically in the range of 0.01 to 5% by weight of the toner particles. Specific examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pentagallo, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. These particles can be used alone or in combination. Polymeric resin particles include, for example, polymer particles made from polystyrene, methacrylate or acrylate copolymers obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization, as well as polycondensation systems such as silicone, benzoguanamine, and nylon, and thermosetting resins.

In the toner of the present invention, when a glycerin fatty acid ester or a polyglycerin fatty acid ester is used in addition to the ketone wax as a release agent, it is preferable to use silica and titanium oxide in combination. Silica and titanium oxide have strong negative charging properties and can change positively charged particles to negatively charged particles without the use of external additives.

Typical examples of hydrophobic treatment agents include the following: Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyltrichlorosilane, decyltrichlorosilane, nonyltrichlorosilane, (4-t-propylphenyl)trichlorosilane, (4-t-butylphenyl) -trichlorosilane, dipentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl-dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl)-octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di-3,3-di Examples include methylpentyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane, dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl)-diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane, and hexatlyldisilazane. Titanate-based coupling agents and aluminum-based coupling agents can also be used.

A general powder mixer is used to mix the above external additives, but it is preferable to equip it with a jacket or other device that allows for adjustment of the internal temperature. For example, a V-type mixer, rocking mixer, Lödige mixer, Nauta mixer, or Henschel mixer is preferably used.

By incorporating the inorganic and resin microparticles into the toner (internal addition), the effect is less than when they are added externally, but they can still improve transferability and durability, and can also improve the grindability of the toner. Furthermore, by using both external and internal addition, it is possible to prevent the externally added microparticles from becoming embedded, resulting in stable, excellent transferability and improved durability.

(Other ingredients)
The toner of the present invention may also contain other components as appropriate depending on the purpose, such as a flowability improver, a cleaning improver, a magnetic material, and a metal soap.

The flow improver refers to a surface treatment that increases hydrophobicity and prevents deterioration of flow and charging properties even under high humidity conditions. Examples include silane coupling agents, silylating agents, silane coupling agents with fluorinated alkyl groups, organic titanate coupling agents, aluminum coupling agents, silicone oil, and modified silicone oil.

The cleaning property improver is added to the toner to remove developer remaining on the electrostatic latent image carrier or intermediate transfer member after transfer. Examples of such agents include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer microparticles produced by soap-free emulsion polymerization, such as polymethyl methacrylate microparticles and polystyrene microparticles. The polymer microparticles preferably have a relatively narrow particle size distribution, with a weight average particle size of 0.01 to 1 μm being preferred.

The magnetic material is not particularly limited and can be appropriately selected from known materials depending on the purpose, such as iron powder, magnetite, and ferrite. Among these, white materials are preferred in terms of color tone.

(Toner manufacturing method)
The method for producing the toner in the present invention is not particularly limited, and the toner can be produced by a melt-kneading pulverization method and a polymerization method, a polyaddition reaction method using an isocyanate group-containing prepolymer, a method of dissolving in a solvent and removing the solvent followed by pulverization, or a melt spray method.
For example, a melt kneading method, a polymerization method (suspension polymerization method/emulsion polymerization method) in which a monomer composition containing a specific crystalline polymer and a polymerizable monomer is directly polymerized in an aqueous phase, a polyaddition reaction method in which a composition containing a specific crystalline polymer and an isocyanate group-containing prepolymer is directly elongated/crosslinked with amines in an aqueous phase, a method in which the resin is dissolved in a solvent, the solvent is removed, and then the resin is pulverized, etc. As mentioned above, in the present invention, a binder resin whose main component is a polyester resin is preferably used.

In the melt-kneading and pulverizing method, suitable devices for melting and kneading the toner include a batch-type two-roll mixer, a Banbury mixer, or a continuous twin-screw extruder, such as a KTK-type twin-screw extruder manufactured by Kobe Steel, Ltd., a TEM-type twin-screw extruder manufactured by Toshiba Machine Co., Ltd., a twin-screw extruder manufactured by KCK Corporation, a PCM-type twin-screw extruder manufactured by Ikegai Iron Works, or a KEX-type twin-screw extruder manufactured by Kurimoto Iron Works, or a continuous single-screw kneader, such as a Ko-Kneader manufactured by Buss.

In the above-mentioned polymerization method and polyaddition reaction method using an isocyanate group-containing prepolymer, it is essential to apply mechanical energy to the aqueous phase to forcibly emulsify (form droplets). Examples of means for applying such mechanical energy include means for applying strong stirring or ultrasonic vibration energy using a homomixer, ultrasound, or Manton-Gaulin mixer.

For crushing, coarse crushing is performed using a hammer mill or rotoplex, and then further crushing can be performed using a fine crusher using a jet stream or a mechanical fine crusher, preferably to obtain an average particle size of 3 to 15 μm. The crushed material is then further adjusted to a particle size of 5 to 20 μm using an air classifier or similar.

The softening temperature (T _1/2 : the temperature at which half of the sample flows out under a given load at elevated temperature) of the toner determined by a flow tester is preferably 115 to 140°C. From the viewpoint of toner storage stability, the glass transition temperature (Tg) is preferably 55 to 70°C, more preferably 57 to 70°C. A Tg of 55°C or higher prevents toner deterioration in a high-temperature atmosphere and also prevents offset during fixing. A Tg of 70°C or lower improves fixability.

When external additives are added to the toner matrix, they are mixed and stirred using a mixer, which disintegrates the additives and coats them on the toner surface. From the perspective of durability, it is important that the external additives, such as inorganic or resin particles, adhere uniformly and firmly to the toner matrix.

(Developer)
The developer using the toner of the present invention may be either a one-component developer or a two-component developer. For example, a 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 is preferably one having a core material and a resin layer covering the core material.
The material for the core material is not particularly limited and can be appropriately selected depending on the purpose. For example, manganese-strontium (Mn—Sr)-based materials and manganese-magnesium (Mn—Mg)-based materials having a repulsion coefficient of 50 emu/g to 90 emu/g are preferred. From the viewpoint of ensuring image density, highly magnetic materials such as iron powder (100 emu/g or more) and magnetite (75 emu/g to 120 emu/g) are preferred. Furthermore, weakly magnetic materials such as copper-zinc (Cu—Zn)-based materials (30 emu/g to 80 emu/g) are preferred, as they can weaken the contact of the toner with the photoreceptor in a spiked state, which is advantageous for achieving high image quality. These materials may be used alone or in combination of two or more.
The volume average particle diameter of the core material is preferably 25 μm or more and 200 μm or less.

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

The mixing ratio of toner and carrier in a two-component developer is preferably 2.0% by mass or more and 12.0% by mass or less, and more preferably 2.5% by mass or more and 10.0% by mass or less, in terms of the mass ratio of toner to carrier.

(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.
The toner container refers to a container that stores toner.
The developing device is a device that contains toner and has means for developing.
The process cartridge is a device that integrates at least an 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.
The toner storage unit of the present invention stores the toner of the present invention.
By mounting the toner storage unit of the present invention in an image forming apparatus and forming an image using the toner of the present invention, an excellent image can be obtained with excellent low-temperature fixability and heat-resistant storage stability.

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

(Image forming method and image forming apparatus)
The image forming apparatus of the present invention includes an electrostatic latent image carrier, electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, transfer means for transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium, and may further include other means such as a discharging means, a cleaning means, a recycling means, and a control means, as necessary.
The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium, and may further include other steps such as a discharging step, a cleaning step, a recycling step, and a control step, as necessary.
In the image forming apparatus and image forming method of the present invention, the toner used is the toner of the present invention, for example, pulverized toner.

The method for producing a printed matter of the present invention is characterized by using the image forming apparatus of the present invention to form a toner image using the toner of the present invention on a recording medium.

(Electrostatic latent image forming process and electrostatic latent image forming means)
The electrostatic latent image forming step is a step of forming an electrostatic latent image on an electrostatic latent image bearing member.
The electrostatic latent image carrier (hereinafter sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") is not particularly limited in terms of material, shape, structure, size, etc., and can be appropriately selected from known ones, but a drum shape is preferred as its shape, and examples of its material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine. Among these, organic photoreceptors (OPC) are preferred because they can produce higher resolution images.
The electrostatic latent image can be formed by, for example, uniformly charging the surface of the electrostatic latent image bearing member and then exposing it to light in an imagewise manner, and can be formed by an electrostatic latent image forming unit.
The electrostatic latent image forming means includes, for example, at least a charging means (charger) that uniformly charges the surface of the electrostatic latent image carrier, and an exposure means (exposure device) that imagewise exposes the surface of the electrostatic latent image carrier.
The charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using the charger.
The charger is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a known contact charger equipped with a conductive or semiconductive roll, brush, film, rubber blade, etc., and a non-contact charger utilizing corona discharge such as a corotron or scorotron.
The charger is preferably one that is disposed in contact with or not in contact with the electrostatic latent image bearing member and charges the surface of the electrostatic latent image bearing member by applying DC and AC voltages in a superimposed manner.
It is also preferred that the charger is a charging roller disposed close to the electrostatic latent image carrier without contacting the electrostatic latent image carrier via a gap tape, and that the surface of the electrostatic latent image carrier is charged by applying a DC voltage and an AC voltage superimposed on the charging roller.
The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member to light in an imagewise manner using the exposure unit.
The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger in the form of an image to be formed, and can be appropriately selected depending on the purpose. Examples of the exposure device include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In the present invention, a backlight system may be employed in which exposure is performed imagewise from the back side of the electrostatic latent image bearing member.

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

(Transfer process and transfer means)
The transfer step is a step of transferring the visible image onto a recording medium. A preferred embodiment is one in which an intermediate transfer body is used, the visible image is primarily transferred onto the intermediate transfer body, and then the visible image is secondarily transferred onto the recording medium. A more preferred embodiment is one in which two or more colors, preferably full-color toner, are used as the toner, and the transfer step includes a primary transfer step in which the visible image is transferred onto the intermediate transfer body to form a composite transfer image, and a secondary transfer step in which the composite transfer image is transferred onto a recording medium.
The transfer means (the primary transfer means, the secondary transfer means) preferably has at least a transfer device that peels and charges the visible image formed on the electrostatic latent image carrier (photosensitive member) onto the recording medium. The number of transfer means may be one or more.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

(Fixing process and fixing means)
The fixing step is a step of fixing the visible image transferred onto the recording medium using a fixing device, and may be performed for each color developer each time it is transferred onto the recording medium, or may be performed simultaneously for each color developer in a stacked state.
The fixing device 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.

The charge removal step is a step of removing electricity by applying a charge removal bias to the electrostatic latent image bearing member, and can be suitably performed by a charge removal unit.
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, and a suitable example is a discharging lamp.

The cleaning step is a step of removing the toner remaining on the electrostatic latent image bearing member, and can be suitably carried out by a cleaning means.
The cleaning means is not particularly limited as long as it can remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Suitable examples include magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

The recycling step is a step of recycling the toner removed in the cleaning step back into the developing means, and can be suitably carried out by a recycling means. There are no particular limitations on the recycling means, and examples include known conveying means.

The control step is a step of controlling each of the steps, and each step can 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 of the means, and can be appropriately selected depending on the purpose. Examples of the control means include devices such as a sequencer and a computer.

FIG. 1 is a schematic explanatory view showing an example of an image forming apparatus of the present invention.
The image forming apparatus 100A includes a photosensitive drum 10, a charging roller 20, an exposure device, a developing device 40, an intermediate transfer belt 50, a cleaning device 60 having a cleaning blade, and a discharging lamp 70.
The intermediate transfer belt 50 is an endless belt stretched by three rollers 51 arranged inside, and can move in the direction of the arrow in Figure 1. Some of the three rollers 51 also function as transfer bias rollers that can apply a transfer bias (primary transfer bias) to the intermediate transfer belt 50. A cleaning device 90 having a cleaning blade is also arranged near the intermediate transfer belt 50. Furthermore, a transfer roller 80 that can apply a transfer bias (secondary transfer bias) to transfer a toner image onto transfer paper 95 is arranged opposite the intermediate transfer belt 50.
In addition, a corona charging device 58 for applying an electric charge to the toner image transferred to the intermediate transfer belt 50 is arranged around the intermediate transfer belt 50, between the contact point between the photosensitive drum 10 and the intermediate transfer belt 50 and the contact point between the intermediate transfer belt 50 and the transfer paper 95, in the direction of rotation of the intermediate transfer belt 50.

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

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

Figure 2 shows a second example of an image forming apparatus used in the present invention. Image forming apparatus 100B has the same configuration as image forming apparatus 100A, except that it does not have a development belt 41 and instead has a black development unit 45K, a yellow development unit 45Y, a magenta development unit 45M, and a cyan development unit 45C arranged directly opposite each other around the photosensitive drum 10.

Figure 3 shows a third example of an image forming apparatus used in the present invention. Image forming apparatus 100C 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.

Intermediate transfer belt 50, located in the center of copying machine main body 150, is an endless belt stretched over three rollers 14, 15, and 16, and can move in the direction of the arrow in Figure 3. Located near roller 15 is cleaning device 17, which has a cleaning blade for removing toner remaining on intermediate transfer belt 50 after the toner image has been transferred to recording paper. Facing intermediate transfer belt 50 stretched over rollers 14 and 15, yellow, cyan, magenta, and black image forming units 120Y, 120C, 120M, and 120K are arranged side by side along the transport direction.

An exposure device 21 is also located near the image forming unit 120. Furthermore, a secondary transfer belt 24 is located on the side of the intermediate transfer belt 50 opposite the side where the image forming unit 120 is located. The secondary transfer belt 24 is an endless belt stretched over a pair of rollers 23, and the recording paper transported on the secondary transfer belt 24 and the intermediate transfer belt 50 can come into contact between rollers 16 and 23.

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

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

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

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

Next, the registration roller 49 is rotated in synchronization with the composite toner image formed on the intermediate transfer belt 50, thereby feeding the recording paper between the intermediate transfer belt 50 and the secondary transfer belt 24, and the composite toner image is transferred (secondary transfer) onto the recording paper. Any toner remaining on the intermediate transfer belt 50 after the composite toner image has been transferred is removed by the cleaning device 17.
The recording paper onto which the composite toner image has been transferred is transported by secondary transfer belt 24, and then the composite toner image is fixed by fixing device 25. Next, the transport path of the recording paper is switched by switching claw 55, and the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56. Alternatively, the transport path of the recording paper is switched by switching claw 55, the sheet is reversed by sheet reversing device 28, an image is formed on the back side in the same manner, and then the recording paper is discharged onto paper discharge tray 57 by discharge rollers 56.

The image forming apparatus and image forming method of the present invention use the toner of the present invention, which combines high levels of grindability, low-temperature fixability, heat resistance, and durability, making it possible to provide high-quality images over a long period of time.

For example, aspects of the present invention are as follows.
<1> A toner containing at least a non-crystalline polyester resin, a crystalline polyester resin, a wax, and an aromatic petroleum resin,
The SP value of the wax is 8.0 or more and 8.5 or less,
The toner is characterized in that the melting point of the wax is 80°C or higher and 100°C or lower, and the ratio of the crystalline polyester resin to the aromatic petroleum resin is 1.0 or higher and 1.2 or lower in mass ratio.
<2> The toner according to <1>, wherein the content of the crystalline polyester resin in the toner is 5.0% by mass or less.
<3> The toner according to <1> or <2>, wherein the content of the aromatic petroleum resin in the toner is 3.0% by mass or more.
<4> The toner according to any one of <1> to <3>, wherein the aromatic petroleum resin is a copolymer of styrene or α-methylstyrene.
<5> The toner according to any one of <1> to <4>, wherein the melting point of the crystalline polyester is 100° C. or higher and 120° C. or lower.
<6> The toner according to any one of <1> to <5>, wherein the weight average molecular weight (Mw) of the aromatic petroleum resin is 2000 to 3500.
<7> The toner according to any one of <1> to <6>, wherein the wax is a Fischer-Tropsch wax.
<8> The toner according to any one of <1> to <7>, wherein the amorphous polyester resin contains at least bisphenol A and ethylene glycol as diol components.
<9> A toner storage unit containing the toner according to any one of <1> to <8>.
<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 with toner to form a toner image;
a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium;
a fixing unit for fixing the toner image transferred onto the surface of the recording medium,
<8> An image forming apparatus, wherein the toner is the toner according to any one of <1> to <8>.
<11> An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image bearing member;
a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium;
a fixing step of fixing the toner image transferred onto the surface of the recording medium,
<8> An image forming method, wherein the toner is the toner according to any one of <1> to <8>.
<12> A method for producing a printed matter, comprising forming a toner image on a recording medium using the image forming apparatus according to <10> and the toner according to any one of <1> to <8>.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these. However, "parts" refers to "parts by mass" unless otherwise specified.

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

(Production of amorphous polyester resin 2)
Amorphous polyester resin 2 was obtained in the same manner as in the production of amorphous polyester resin 1, except that the types of monomers used were changed as shown in Table 2 below.

(Production of crystalline polyester 1)
Fumaric acid and 1,6-hexanediol were charged into a 5 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple so that the OH/COOH ratio of the mixture was 0.9, and reacted together with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours. The mixture was then heated to 200°C and reacted for 3 hours, and then further reacted at a pressure of 8.3 kPa for 2 hours to obtain crystalline polyester 1 having a melting point of 103°C.

(Production of crystalline polyester 2)
Fumaric acid and 1,6-hexanediol were charged into a 5 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple so that the OH/COOH ratio of the mixture was 0.93, and reacted together with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours. The mixture was then heated to 200°C and reacted for 3 hours, and then further reacted at a pressure of 8.3 kPa for 2 hours to obtain crystalline polyester 2 having a melting point of 117°C.

(Production of crystalline polyester 3)
Fumaric acid and 1,6-hexanediol were charged into a 5 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple so that the OH/COOH ratio of the mixture was 0.85, and reacted together with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours. The mixture was then heated to 200°C and reacted for 3 hours, and then further reacted at a pressure of 8.3 kPa for 2 hours to obtain crystalline polyester 3 having a melting point of 97°C.

(Production of Crystalline Polyester 4)
Fumaric acid and 1,6-hexanediol were charged into a 5 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple so that the OH/COOH ratio of the mixture was 0.96, and reacted together with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours. The mixture was then heated to 200°C and reacted for 3 hours, and then further reacted at a pressure of 8.3 kPa for 2 hours to obtain crystalline polyester 4 having a melting point of 123°C.

<Examples and Comparative Examples>
(Example 1):
- Preparation of toner base particles 1 -
Non-crystalline polyester resin 1: 86.4 parts Crystalline polyester resin 1: 4.8 parts Aromatic petroleum resin: FTR-2140 (styrene copolymer manufactured by Mitsui Chemicals, Inc.) 4.8 parts Wax: Wax 1 4 parts Carbon black (#44 manufactured by Mitsubishi Chemical Corporation): 10 parts

According to the above recipe, the toner raw materials were premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.). The resulting kneaded material was rolled to a thickness of 2.7 mm using rollers, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 300 μm using a hammer mill. Next, the mixture was finely pulverized using a supersonic jet pulverizer Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) with the louver opening appropriately adjusted to achieve a weight-average particle size of 5.8±0.2 μm, yielding toner base particles 1 for Example 1.

(Examples 2 to 14) and (Comparative Examples 1 to 6)
--Preparation of toner base particles 2 to 20--
Toner base particles 2 to 20 of Examples 2 to 14 and Comparative Examples 1 to 6 were obtained by the same procedure except that the type and number of parts of the amorphous polyester resin, the type and number of parts of the crystalline polyester resin, the type and number of parts of the aromatic petroleum resin, and the type of wax used were changed as shown in Table 3.

The manufacturer, composition, and physical properties of the aromatic petroleum resin used are as follows:

The types of wax used, their SP values and melting points are as follows:

(Preparation of Toner Developer)
An externally-added toner was prepared by stirring and mixing 1 part by weight of HDK-2000 (Clariant) metal oxide fine particles with 100 parts by weight of the above-mentioned toner base particles in a Henschel mixer. 5% by weight of this externally-added toner and 95% by weight of a coated ferrite carrier were uniformly mixed at 48 rpm for 5 minutes in a Turbler mixer (manufactured by Willy & Bachofen (WAB)) to prepare a toner developer. This toner developer was evaluated for grindability, low-temperature fixability, heat-resistant storage stability, and durability using the following evaluation methods.

(Evaluation of grindability)
In the toner base particle manufacturing process, the particles were finely pulverized using a supersonic jet pulverizer, Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and the weight average particle size was measured, and the pulverizability was evaluated based on the following evaluation criteria.
- Evaluation criteria for grindability -
⊚: Less than 5.3 μm ◯: 5.3 μm or more and less than 5.5 μm x: 5.5 μm or more Evaluations of ⊚ and ◯ can be judged to be sufficient results for practical use.

(Evaluation of low-temperature fixability)
The toner developer was placed in a Ricoh MPC 6003 copier, and an image was output. A solid image with a deposition amount of 0.4 mg/ ^cm2 was output on paper (Ricoh Type 6200) through exposure, development, and transfer processes. The fixing linear speed was 256 mm/sec. The fixing temperature was sequentially increased in 5°C increments, and the lowest temperature at which cold offset did not occur (lower fixing temperature: low-temperature fixability) was measured. The NIP width of the fixing device was 11 mm.
-Evaluation criteria for low-temperature fixability-
⊚: Less than 120°C ◯: 120°C or more and less than 130°C x: 130°C or more Evaluations of ⊚ and ◯ can be judged to be sufficient results for practical use.

(Evaluation of heat-resistant storage stability)
The toner base particles were stored at 50° C. for 24 hours, and the penetration was measured in accordance with JIS K2235 (25° C.) using a penetrometer VR-5610 (Shimadzu Corporation).
-Evaluation criteria for heat resistance and storage stability-
◎: 4.0 mm or more 〇: 0.5 mm or more and less than 4.0 mm ×: less than 0.5 mm Evaluations of ◎ and 〇 can be judged to be sufficient results for practical use.

(durability)
Using a low-temperature fixing copier, imajio MF-6550 manufactured by Ricoh, 100,000 copies of a test chart with an image area of 6% were made, and the degree of decrease in the charge amount of the developer was evaluated.
⊚: Very little decrease in charge amount and excellent durability ◯: Little decrease in charge amount and excellent durability compared to conventional toners ×: Poor durability equal to or less than conventional toners Evaluations of ⊚ and ◯ can be judged to be sufficient results for practical use.

The evaluation results for each toner are shown in Table 6.

The results in Table 6 show that the toners of each example are able to achieve high levels of grindability, low-temperature fixability, heat resistance, and durability.

10 Electrostatic latent image carrier (photosensitive drum)
14 Roller 15 Roller 16 Roller 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet inverting device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Developing device 41 Developing belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Developing roller 44Y Developing roller 44M Developing roller 44C Developing roller 45K Black developing unit 45Y Yellow developing unit 45M Magenta developing unit 45C Cyan developing unit 49 Registration roller 50 Intermediate transfer belt 51 Roller 52 Separation roller 53, manual paper feed path 54, manual feed tray 55, switching claw 56, discharge roller 57, discharge tray 58, corona charging device 60, cleaning device 61, developing device 62, transfer roller 63, photoconductor cleaning device 64, charge removal lamp 70, charge removal lamp 80, transfer roller 90, cleaning device 95, transfer sheets 100A, 100B, 100C, image forming device 120, image forming unit 130, document table 142, paper feed roller 143, paper bank 144, paper feed cassette 145, separation roller 146, paper feed path 147, transport roller 148, paper feed path 150, copying machine main body 200, paper feed table 300, scanner 400, automatic document feeder (ADF)

Patent No. 5152372 Patent No. 4535017 Patent No. 3525216 Japanese Patent Application Laid-Open No. 2007-264222 JP 2014-056143 A Japanese Patent Application Laid-Open No. 2021-144186

Claims (10)

A toner containing at least a non-crystalline polyester resin, a crystalline polyester resin, a wax, and an aromatic petroleum resin,
The SP value of the wax is 8.0 or more and 8.5 or less,
The melting point of the wax is 80°C or higher and 100°C or lower, and the ratio of the crystalline polyester resin to the aromatic petroleum resin is 1.0 or higher and 1.2 or lower in mass ratio,
the aromatic petroleum resin is a copolymer of styrene or α-methylstyrene,
The toner is characterized in that the amorphous polyester resin contains at least bisphenol A and ethylene glycol as diol components . The toner according to claim 1, characterized in that the content of the crystalline polyester resin in the toner is 5.0% by mass or less. The toner according to claim 1, characterized in that the content of the aromatic petroleum resin in the toner is 3.0% by mass or more. 2. The toner according to claim 1, wherein the melting point of the crystalline polyester resin is 100° C. or higher and 120° C. or lower. The toner according to claim 1, characterized in that the weight average molecular weight (Mw) of the aromatic petroleum resin is 2000-3500. The toner according to claim 1, wherein the wax is a Fischer-Tropsch wax. A toner storage unit containing the toner according to any one of claims 1 to 6 . an electrostatic latent image carrier;
an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
a developing unit that develops the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
a transfer means for transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium;
a fixing unit for fixing the toner image transferred onto the surface of the recording medium,
7. An image forming apparatus, wherein the toner is the toner according to claim 1 . an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier;
a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
a transfer step of transferring the toner image formed on the electrostatic latent image carrier onto a surface of a recording medium;
a fixing step of fixing the toner image transferred onto the surface of the recording medium,
7. An image forming method, wherein the toner is the toner according to claim 1 . A method for producing a printed matter, comprising forming a toner image on a recording medium using the toner according to any one of claims 1 to 6 , by using the image forming apparatus according to claim 8 .