JP5495036B2 - Image forming toner, one-component developer, two-component developer, image forming method, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to an image forming toner, a one-component developer, a two-component developer, an image forming method, an image forming apparatus, and a process cartridge.

The demand for the image quality of the image output by the image forming apparatus is increasing year by year, and further improvement in image quality is desired. With this higher image quality, technically stricter conditions are required. In particular, in recent years when an electrophotographic system is being used for on-demand digital printing, it is necessary to output a high-quality image equivalent to or exceeding that of offset printing.

For example, a lake pigment derived from a dye as disclosed in Patent Document 1 (Patent No. 2584450) is obtained by insolubilizing a dye with a highly polar inorganic oxide and has a wide color reproduction range. Therefore, it is a useful material that responds to the voice of the market that desires the formation of higher quality images.

A conventional toner manufacturing method, for example, a pulverization method found in Patent Document 2 (Japanese Patent No. 4169493) melts and kneads a toner material containing a pigment and a resin and disperses the pigment in the toner particles. Regardless of the chemical properties, various types of pigments including the lake pigments could be used.

However, in recent years, the pulverization method pulverizes and classifies a composition obtained by melting and kneading a toner material, so that the particle size distribution of the toner tends to be widened, and toner particles are used to obtain an image with good resolution and gradation. The average particle size of the toner has to be reduced, requires a lot of energy for pulverization and classification, the toner yield is low, the amount of CO ₂ emission during production is large, and it is avoided from environmental considerations. It is difficult to uniformly disperse a colorant, a charge control agent, and the like in the binder resin, and the non-uniform dispersion adversely affects toner fluidity, developability, durability, image quality, and the like.

As a method for producing a toner having a sharp particle size distribution and capable of uniformly dispersing a colorant, a charge control agent, and the like in a binder resin, for example, an aqueous system disclosed in Patent Document 3 (Japanese Patent No. 4298904) is disclosed. In many cases, a toner is produced by a polymerization method obtained by emulsification, dissolution and suspension in a medium. In this polymerization method, a toner material is dispersed in a solution and granulated.

When the lake pigment derived from the dye is used in the polymerization method, since the pigment has high polarity, it may not only adversely affect the dispersibility of other toner materials in the solution, but the lake pigment may be used during the production of the toner. The colorant that can be used is limited because it dissolves in an aqueous solvent and it is difficult to control the pigment concentration in the toner particles, and the wastewater treatment is costly. The above problem occurs not only with lake pigments but also with strongly hydrophilic pigments.

As described above, the conventional lake pigments or hydrophilic pigments have a drawback that their use in the polymerization method is limited even if they have a wide color reproduction range.

An object of the present invention is to rake hydrophilic pigments or dyes having a wide color reproduction range and high saturation while being easily eluted in an aqueous medium and having low dispersibility in toner particles. It is to provide a toner having a wide color reproduction range, a high chroma, and a sharp particle size distribution by making the converted pigment usable for a toner granulated in an aqueous medium.
Another object of the present invention is to provide a one-component developer or two-component developer using the toner, an image forming method using the image forming toner, an image forming apparatus, and a process cartridge.

As a result of intensive studies on image forming toners, the present inventors have found that the above problems can be solved by the following method. Specifically, in order to solve the above-described problems, an image forming toner, a one-component developer, a two-component developer, an image forming method, an image forming apparatus, or a process cartridge using the toner according to the present invention are specifically described. It has the technical features described in the following (1) to (12).

The present invention is solved by the following (1) to ( 11 ).
(1) A toner having at least a binder resin and a colorant and granulated in an aqueous solvent,
The colorant, hydrophilic pigments or dyes are pigments and lake, and state, and are not allowed to fix the inorganic particles on the pigment surface, the inorganic fine particles, 5 weight per 100 parts by weight of pigment An image forming toner comprising 30 parts by weight or more .
( 2 ) The image forming toner according to (1), wherein the inorganic fine particles have an average particle diameter of 10 nm to 100 nm.
(3) The image forming toner according to (1) or (2), wherein the inorganic fine particles are silica fine particles that have been subjected to a hydrophobic treatment.
( 4 ) The image forming toner as described in any one of (1) to (3 ) above, wherein the colorant is a pigment obtained by forming a rhodamine dye into a lake.
( 5 ) A one-component developer comprising the image forming toner according to any one of (1) to ( 4 ).
( 6 ) A two-component developer comprising the image forming toner according to any one of (1) to ( 4 ) and a carrier.
( 7 ) A charging step for charging at least the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image with toner to make it visible An image forming method comprising: a developing step for forming an image; a transfer step for transferring the visible image onto a recording medium to form an unfixed image; and a fixing step for fixing the unfixed image on the recording medium. An image forming method, wherein the toner used to form the visible image is the image forming toner according to any one of (1) to ( 4 ).
( 8 ) The image forming method as described in ( 7 ) above, wherein the conveyance speed of the recording medium in the fixing step is 280 mm / second or more.
( 9 ) At least the image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and the electrostatic latent image Developing means for developing a visible image by using toner, transfer means for transferring the developed toner image onto a recording medium to form an unfixed image, and fixing the unfixed image to the recording medium And an image forming apparatus including the fixing unit. The toner used for forming the visible image is the image forming toner according to any one of (1) to ( 4 ). An image forming apparatus.
( 10 ) The image forming apparatus according to ( 9 ), wherein a conveyance speed of the recording medium during fixing by the fixing unit is 280 mm / second or more.
( 11 ) An image carrier, charging means for charging the surface of the image carrier, exposure means for exposing the charged image carrier surface to form an electrostatic latent image, and forming the electrostatic latent image into toner And at least one means selected from a developing means for developing using toner, a transferring means for transferring the developed toner image to a recording medium, and a cleaning means for removing toner remaining on the surface of the image carrier after transfer. And a process cartridge that is removable from the main body of the image forming apparatus, wherein the toner to be used is the image forming toner according to any one of (1) to ( 4 ). cartridge.

As will be understood from the following detailed and specific description, the toner of the present invention, the one-component developer and the two-component developer using the toner have a wide color reproduction range, high saturation, and particle size. The distribution is sharp, and in electrophotographic image formation, it is possible to output an image with significantly higher image quality than in the past.
According to the image forming apparatus of the present invention, since the excellent image forming toner capable of outputting a high-quality image is used, it is possible to output a high-quality and stable image even when the process linear speed is high.
The image forming method and the image forming apparatus of the present invention can be widely applied to electrophotographic application fields using electrophotography (for example, electrostatic copying machines, laser beam printers, etc.).
Further, according to the process cartridge of the present invention, since the toner of the present invention is supplied from the developing means, an excellent image capable of outputting a high-quality image can be output.

It is explanatory drawing which shows an example of the image forming method of this invention.

The image forming toner of the present invention will be described in detail.
The present invention is a toner having at least a binder resin and a colorant, and granulated in an aqueous solvent, wherein the colorant is a hydrophilic pigment or a pigment obtained by lake formation of a dye, and An image-forming toner having inorganic fine particles on the pigment surface.
That is, a hydrophilic pigment or a pigment raked from a dye that has a wide color reproduction range and exhibits high saturation, is easily eluted in an aqueous medium, and has low dispersibility in toner particles. The toner can be used for a toner granulated in an aqueous medium. By fixing inorganic particles on the surface of the hydrophilic pigment or pigment-laminated pigment, the pigment is applied to the aqueous medium. It is a toner that can prevent elution and improve dispersibility in toner particles, has a wide color reproduction range, exhibits high saturation, has a sharp particle size distribution, and can output a high-quality image.

(Use of lake pigments and hydrophilic pigments in polymerized toners)
Lake pigments are obtained by fixing water-soluble dyes such as acid dyes and basic dyes to extender pigments, which are inorganic compounds, and often have high-concentration and clear hues. Since the laked pigment has polarity, its dispersibility is greatly influenced by the properties of the aqueous medium.
For example, insolubilized pigments such as CI Pigment Red 48, 57, 81, Pigment Blue 15: 3, Pigment Yellow 74, 139, 155, 180, 185, Pigment Red 122, 184, 269, etc. were hydrophilically treated. Even with pigments, problems such as elution into an aqueous medium without being encapsulated in the toner or uniform dispersion within the toner occur. That is, there are cases in which a pigment having a wide color reproducibility cannot be used for a toner granulated in an aqueous medium as it is.

In the present invention, the surface of a hydrophilic pigment or pigment-laminated pigment is treated with inorganic fine particles to fix the inorganic fine particles. Silica, titania, alumina, zinc oxide, tin oxide, etc. can be used as the inorganic fine particles that can be fixed to the pigment surface. Among them, the silica fine particles have a strong negative chargeability. It is fixed by pigment fine particles and stronger Coulomb force than inorganic fine particles having relatively high conductivity such as zinc and tin oxide.
The silica fine particles used for the surface treatment are preferably hydrophobized so that elution into the aqueous medium can be prevented and the pigment can be uniformly dispersed inside the toner particles.
As the hydrophobizing agent for silica fine particles, known ones can be used. For example, silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum Preferred coupling agents, silicone oils, modified silicone oils and the like are listed as preferred surface treatment agents.

The inorganic fine particles vary depending on the degree of hydrophilicity and particle size of the pigment used and the degree of aggregation of the inorganic fine particles, but in order to sufficiently cover the surface of the pigment, the average particle size is preferably 10 nm to 100 nm, and 100 parts by weight of the pigment The amount is preferably 5 to 30 parts by weight, more preferably 15 to 30 parts by weight. This is because it is related to the surface area of the pigment.
If it is less than 5 parts by weight, the surface of the pigment is not covered with inorganic fine particles and many hydrophilic parts are exposed, the pigment is likely to migrate into the aqueous medium, and the dispersion in the toner particles (oil phase) is not uniform. It may not be possible to suppress adverse effects such as becoming.
The addition amount is preferably 5 parts by weight or more because “wetting” between the pigment surface and the aqueous medium can be suppressed. The addition amount of 15 parts by weight or more can cover the pigment surface almost completely with inorganic fine particles. This is more preferable because the effect of preventing wetting with an aqueous medium is enhanced.
However, when the addition amount is higher than 30 parts by weight, the intensity of the absorption / reflection light peculiar to the pigment is weakened by scattering due to the surface-treated inorganic material, and on the contrary, the image quality may be deteriorated.

By mixing and stirring these pigments and inorganic fine particles and attaching the inorganic fine particles to the surface of the pigment, it is possible to use the hydrophilic pigment or the pigment raked in an aqueous medium. Become. However, in the treatment of the inorganic fine particles dispersed in the liquid, the pigment is eluted in the treatment liquid, and the treatment speed is slower than that of the stirrer used in the air, and the pigment particles and the inorganic fine particles are sufficient. Adhesion is difficult to obtain.
In order to fix inorganic fine particles to the pigment surface, a hybridizer NHS-0 type machine manufactured by Nara Machinery Co., Ltd. can be preferably used.
In the present invention, the term “inorganic fine particles are fixed on the pigment surface” means that the pigment in the aqueous medium is stirred under the same conditions as in the toner granulation step and the pigment does not elute.

(Dye and pigment)
As the colorant used in the image forming toner of the present invention, 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, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL , Isoindolinone yellow, bengara, red lead, red lead, cadmium red, cadmium mercury red, antimony red, permanent red 4R, para red, phise red, parachlor ortho nitroaniline red, risor fast scarlet G, Reliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon , Oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine Range, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo , Ultramarine, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt violet, manganese violet, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridiane, emerald green, pigment green B, naphthol green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Oxidized Chi Tan, zinc white, lithopone and mixtures thereof. Further, those colorants that have been subjected to hydrophilicity or hydrophobic treatment by a known method such as introduction of a functional group can be used if necessary, but those that are basic capable of firmly fixing silica fine particles are preferable.
The content of the colorant is usually 1 to 15% by weight based on the image forming toner.

  In the present invention, a master batch in which the colorant and the resin are combined may be used. The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene or a substituted polymer thereof, a styrene copolymer, polymethyl methacrylate, polybutyl methacrylate , Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, alicyclic ring Aromatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the polymer of styrene or a substituted product thereof include polyester resin, polystyrene, poly p-chlorostyrene, polyvinyl toluene, and the like. Examples of the styrene copolymer include a styrene-p-chlorostyrene copolymer, a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, a styrene-vinylnaphthalene copolymer, and a styrene-methyl acrylate copolymer. Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Butyl methacrylate copolymer, styrene-p-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene An acrylonitrile-indene copolymer, Styrene - maleic acid copolymer, styrene - maleic acid ester copolymer, and the like.

The binder resin is preferably a polyester resin in order to achieve both heat-resistant storage stability and low-temperature fixability.
Examples of the monomer constituting the polyester resin include, but are not limited to, the following.

Examples of the divalent alcohol component include ethylene glycol, 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, diol obtained by polymerizing cyclic ethers such as ethylene oxide and propylene oxide to bisphenol A, and the like. Can be mentioned.

Examples of acid components that form polyester polymers include benzene dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, or anhydrides thereof, alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or the like. Unsaturated dibasic acids such as anhydride, maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydrides, and the like.

  Examples of the trivalent or higher polyvalent carboxylic acid component include trimet acid, pyromellitic 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, emporic trimer acid, or their anhydrides, partially lower alkyl esters, and the like.

If necessary, the toner of the present invention may contain a release agent, a charge control agent, an external additive and the like as long as the effects of the present invention are not impaired.

(Release agent)
There is no restriction | limiting in particular as a mold release agent used for the toner for image formation of this invention, According to the objective, it can select suitably from well-known things, For example, waxes etc. are mentioned suitably. The melting point of the wax as the release agent is preferably 70 to 150 ° C. When the temperature is lower than 70 ° C., the heat-resistant storage stability of the toner is inferior. The amount of these release agents used is preferably 2 to 15% by weight based on the toner. If it is less than 2% by weight, the effect of preventing offset is insufficient, and if it exceeds 15% by weight, transferability and durability are deteriorated.

  A conventionally well-known thing can be used for the said wax. For example, low molecular weight polyethylene, low molecular weight polypropylene and other low molecular weight polyolefin waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, beeswax, carnauba wax, candelilla wax, rice wax, montan wax and other natural waxes, Examples include petroleum waxes such as paraffin wax and microcrystalline wax, higher fatty acids such as stearic acid, palmitic acid, and myristic acid, metal salts of higher fatty acids, higher fatty acid amides, synthetic ester waxes, and various modified waxes thereof. These waxes can be used alone or in combination of two or more.

  Of these, carnauba wax and its modified wax, polyethylene wax, and synthetic ester wax are preferably used. In particular, the synthetic ester wax pentaerythritol tetrabehenate is most preferred. The reason is that carnauba wax, its modified wax and synthetic ester wax are appropriately finely dispersed with respect to polyester resin and polyol resin, so that it is easy to make a toner excellent in offset prevention, transferability and durability. It is.

(Charge control agent)
As the charge control agent used in the present invention, any conventionally known charge control agent can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus Simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like.

  Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo And pigments and other high molecular compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

  The content of the charge control agent is appropriately determined according to desired charging characteristics, but is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight with respect to the binder resin 100. preferable. When the addition amount exceeds 10% by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is reduced, the image The concentration may decrease. On the other hand, if the addition amount is less than 0.1% by weight, the charge rising property and the charge amount are not sufficient, and the toner image may be easily affected.

(External additive)
The toner of the present invention is obtained by a polymerization method obtained by emulsifying, dissolving and suspending in an aqueous medium. In order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles (external additives) may be further added and mixed with the manufactured toner base particles. For mixing such additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the additive, the additive may be added midway or gradually. In this case, you may change the rotation speed, rolling speed, time, temperature, etc. of a mixer. Alternatively, a strong load may be applied first, then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, and a Henschel mixer. Next, the toner is obtained by passing through a sieve of 250 mesh or more to remove coarse particles and aggregated particles.

As the external additive used in the present invention, inorganic fine particles are preferably used for the purpose of imparting fluidity, chargeability and developability. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The amount of the inorganic fine particles added is preferably 0.01 to 5 wt% of the image forming toner.

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

Such external additives can be surface treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  The weight average particle diameter of the image forming toner of the present invention is not particularly limited and can be appropriately selected according to the purpose. However, in order to obtain a high-quality image having excellent granularity, sharpness, and fine line reproducibility. The weight average particle diameter is preferably 3.5 μm to 10 μm. The smaller the particle size, the better the image sharpness and fine line reproducibility. In particular, in a color image forming apparatus, a demand for image quality is strict and a toner of 10 μm or less is required. In particular, 7.5 μm or less is preferable for image quality. On the other hand, if the toner particle diameter is too small, such as less than 3.5 μm, the toner fluidity and transferability deteriorate. Here, the weight average particle diameter of the toner can be obtained as follows.

(Measurement of weight average particle diameter (Dw) of toner)
As an apparatus for measuring the particle size distribution of toner particles by the Coulter counter method, there are Coulter Counter TA-II and Coulter Multisizer III (both manufactured by Coulter). In the present invention, measurement was performed as follows using Coulter Multisizer III.

  First, 0.1 to 5 ml of a surfactant, preferably polyoxyethylene alkyl ether, is added as a dispersant to 100 to 150 ml of an electrolytic aqueous solution. Here, the electrolytic solution is an about 1% NaCl aqueous solution prepared using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Dw) and the number average particle diameter (Dn) of the toner can be obtained.

  The channel in the above measurement is as follows: 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to 6.35 μm Less than 6.35 to less than 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; ≦ 25.40 μm; 25.40 to less than 32.00 μm; 13 channels of 32.00 to less than 40.30 μm are used, and particles having a particle diameter of 2.00 μm to less than 40.30 μm are targeted.

The image forming toner of the present invention can be used as a one-component developer or a two-component developer. That is, the one-component developer is composed of only the image forming toner, and the two-component developer is composed of the image forming toner and the carrier.

(Single component developer)
In the one-component developer, it can be used as a non-magnetic one-component toner or a magnetic one-component toner (magnetic toner). When used as a magnetic toner, a known magnetic material can be used. That is, magnetic materials contained in the magnetic toner include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum, cobalt, copper, lead, magnesium, tin, and the like of these metals. Examples include alloys of metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. These ferromagnetic materials desirably have an average particle size of about 0.1 to 2 μm. The amount of the ferromagnetic material contained in the toner is 20 to 200 parts by weight, particularly preferably 100 parts by weight of the resin component, with respect to 100 parts by weight of the binder resin. 40 to 150 parts by weight per part.

(Two-component developer)
As the carrier used in the two-component developer of the present invention, a conventionally known carrier can be used. For example, a carrier made of magnetic particles such as iron or ferrite, a resin-coated carrier in which such magnetic particles are coated with a resin, or a binder-type carrier in which magnetic fine powder is dispersed in a binder resin. Can be used.
Magnetic materials include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, Metal alloys such as calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof can be used.
Among these carriers, a silicone resin, a copolymer resin (graft resin) of an organopolysiloxane and a vinyl monomer, or a resin-coated carrier using a polyester resin can be used as a coating resin, such as toner spent. A carrier coated with a resin obtained by reacting an isocyanate with a copolymer resin of an organopolysiloxane and a vinyl monomer is preferable from the viewpoint of durability, environmental stability, and spent resistance. . As the vinyl monomer, it is necessary to use a monomer having a substituent such as a hydroxyl group reactive with isocyanate.

  In addition to the above, examples of carrier coating materials used for carriers include amino resins such as urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, and epoxy resins. Polyvinyl and polyvinylidene resins, acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and polystyrene resins such as styrene-acrylic copolymer resins, poly Halogenated olefin resins such as vinyl chloride, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoropropylene Resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and fluoride Vinylidene fluoro such as terpolymers of non-fluorinated monomer, and silicone resins.

Moreover, you may make conductive powder etc. contain as a filler in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide, aluminum oxide, silica and the like can be used. These preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it is difficult to control electric resistance in the case of conductive powder.
It is preferable to use a magnetic carrier having a volume average particle diameter of 20 to 100 μm, preferably 20 to 60 μm from the viewpoint of ensuring high image quality and preventing carrier fogging.

(Method for producing toner granulated in aqueous medium)
A method for producing toner granulated in the aqueous medium of the present invention will be described with reference to examples.
Toner (polymerized toner) granulated in an aqueous medium is first a toner material liquid in which the above colorant, unmodified polyester, polyester prepolymer (A) having an isocyanate group, and a release agent are dispersed in an organic solvent. (Oil phase) is prepared, dispersed in an aqueous medium, emulsified and suspended, granulated, then the organic solvent is removed, washed and dried.

(Polyester prepolymer having isocyanate group (A))
Polyester is reacted with, for example, a carboxyl group or a hydroxyl group at the terminal of a polyester obtained by polycondensation reaction of polyhydric alcohol (PO) and polyhydric carboxylic acid (PC) with a polyisocyanate compound (PIC) to obtain isocyanate. A polyester prepolymer (A) having a group is preferably used.
The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

(Organic solvent)
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part. The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.

(Aqueous medium)
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

(Surfactant, resin fine particles)
Further, the reason why a dispersant such as a surfactant and resin fine particles is appropriately added to the aqueous medium is to improve the dispersion of the colorant, the unmodified polyester, the polyester prepolymer having an isocyanate group, the release agent, and the like. .
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.
Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).
In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. , Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries, Ltd.) Manufactured), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footgent F-300 (Neos), and the like.

(Resin fine particles)
As the resin fine particles, any resin can be used as long as it can form an aqueous dispersion, and it may be a thermoplastic resin or a thermosetting resin. Examples thereof include vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. As the resin, two or more of the above resins may be used in combination.
Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained. For example, vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid-acrylic acid esters. Examples thereof include resins such as a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer. The average particle size of the resin fine particles is 5 to 200 nm, preferably 20 to 300 nm. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

(Dispersant)
As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

(Distribution method)
The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Simultaneously with the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
Examples of the amines (B) include diamine (B1), triamine or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and (B1) to (B5). Examples thereof include an amino group blocked (B6).
Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diamines). Cyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.) and the like.
Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.
As (B6) which blocked the amino group of (B1) to (B5), ketimine compounds obtained from the amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) of (B1) to (B5), Examples include oxazoline compounds. Among these amines (B), preferred are (B1) and a mixture of (B1) and a small amount of (B2).
The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance deteriorates.
Since this reaction involves crosslinking and / or elongation of molecular chains, a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.
The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

(Removal of organic solvent, washing, drying)
After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation. A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are adhered to the base particles as external additives to obtain a toner. The charge control agent is injected and the inorganic fine particles are externally added by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

(Image forming method)
The image forming method of the present invention comprises at least a charging step for charging the surface of an image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the image carrier, and the electrostatic latent image for image formation. A development process for forming a visible image by developing with toner, a transfer process for transferring the visible image onto a recording medium to form an unfixed image, and fixing the unfixed image on the recording medium The image forming method includes a fixing step, and the image forming toner used for forming the visible image is the image forming toner described above. Here, the toner for image formation can be satisfactorily fixed even if the conveyance speed of the recording medium in the fixing step is 280 mm / second or more.

  Next, an example of the image forming method of the present invention will be described with reference to FIG. The image forming apparatus shown in FIG. 1 is a tandem color image forming apparatus. The image forming apparatus includes a copying machine main body, a paper feed table (200), a scanner (300), and an automatic document feeder (ADF) (400).

  The copying machine main body is provided with an endless belt-like intermediate transfer member (10) at the center. The intermediate transfer member (10) is stretched around the support rollers (14), (15) and (16), and can rotate clockwise in FIG. A cleaning device (17) for removing residual toner on the intermediate transfer member (10) is disposed in the vicinity of the support roller (15). The intermediate transfer member (10) stretched by the support roller (14) and the support roller (15) has four image forming units (18) of yellow, cyan, magenta, and black along the conveyance direction. Image forming means (20) arranged opposite to each other are arranged. An exposure device (21) is disposed in the vicinity of the image forming means (20). A secondary transfer device (22) is disposed on the side of the intermediate transfer member (10) opposite to the side on which the image forming means (20) is disposed. In the secondary transfer device (22), a secondary transfer belt (24), which is an endless belt, is stretched between a pair of support rollers (23), and the recording paper conveyed on the secondary transfer belt (24). And the intermediate transfer member (10) can contact each other. A fixing device (25) is arranged in the vicinity of the secondary transfer device (22). The fixing device (25) includes a fixing belt (26) that is an endless belt and a pressure roller (27) that is pressed against the fixing belt (26). A reversing device (28) for reversing the recording paper for forming images on both sides of the recording paper is disposed in the vicinity of the secondary transfer device (22) and the fixing device (25).

  Next, formation of a full color image (color copy) using the image forming means (20) will be described. First, the document is set on the document table (30) of the automatic document feeder (ADF) (400) or the automatic document feeder (400) is opened, and the document is placed on the contact glass (32) of the scanner (300). Is set and the automatic document feeder (400) is closed.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32). ) When the original is set on the scanner, the scanner (300) is immediately driven, and the first traveling body (33) and the second traveling body (34) travel. At this time, light from the light source is irradiated by the first traveling body (33), and reflected light from the document surface is reflected by the mirror in the second traveling body (34). Further, the image is received by the reading sensor (36) through the imaging lens (35), and the original is read to obtain black, yellow, magenta and cyan image information. Next, each image information is transmitted to each image forming unit (18) in the image forming means (20), and a visible image of each color of black, yellow, magenta and cyan is formed.

  As shown in FIG. 1, the image forming unit (18) includes a charging device (no symbol) for uniformly charging the photoconductor (40) and an exposure device (21) based on each image information. The electrostatic latent image formed by exposing the photoconductor (40) like an image is developed using each toner (black toner, yellow toner, magenta toner, and cyan toner), and a visible image formed by each toner. A developing device (no symbol), a transfer charger (no symbol) for transferring a visible image onto the intermediate transfer member (10), a cleaning device (no symbol) and a charge eliminating device (no symbol). Thus, it is possible to form a visible image of each color based on each image information. Next, the visible images of the respective colors are sequentially transferred (primary transfer) onto the intermediate transfer body (10) rotated and moved by the support rollers (14), (15) and (16), and the visible images of the respective colors are obtained. Are superimposed to form a composite transfer image.

  On the other hand, in the paper feed table (200), one of the paper feed rollers (42) is selectively rotated to feed the recording paper from one of the paper feed cassettes (44) provided in the paper bank (43) in multiple stages. The paper is separated one by one by the separation roller (45), sent to the paper feed path (46), transported by the transport roller (47), led to the paper feed path (48) in the copying machine main body, and the registration roller (49 ) And stop. Alternatively, the paper feed roller (42) is rotated to feed out the recording paper on the manual feed tray (51), separated one by one by the separation roller (52), and put into the manual paper feed path (53). 49) and stop. The registration roller (49) is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the recording paper. Then, the registration roller (49) is rotated in time with the composite transfer image formed on the intermediate transfer member (10), and the recording paper is interposed between the intermediate transfer member (10) and the secondary transfer device (22). And a composite transfer image is transferred onto the recording paper (secondary transfer) by the secondary transfer device (22), whereby a color image is formed on the recording paper. The toner remaining on the intermediate transfer member (10) is removed by the cleaning device (17).

  The recording paper on which the color image is formed is conveyed by the secondary transfer device (22) and sent to the fixing device (25), where the composite transfer image is heated and pressure-fixed on the recording paper in the fixing device (25). Is done. Thereafter, the recording paper is switched by the switching claw (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55), reversed by the reversing device (28) and led again to the transfer position, and after forming an image on the back surface, it is ejected by the ejection roller (56) and ejected by the ejection tray (57). Stacked on top.

  According to the image forming method of the present invention, an image forming toner that has excellent low-temperature fixability and heat-resistant storage stability even at high speed and is fixed only at a desired position on a recording medium without causing an offset phenomenon is used. Therefore, even when an image is formed by an electrophotographic image forming apparatus having a high output speed, it is excellent in glossiness, and it is possible to stably output a high-quality image without generating a ghost or the like.

(Image forming device)
The image forming apparatus of the present invention includes at least an image carrier, a charging unit that charges the surface of the image carrier, and an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image. Developing means for developing the electrostatic latent image using an image forming toner to form a visible image; and transfer means for transferring the developed toner image onto a recording medium to form an unfixed image; And an image forming apparatus provided with a fixing means for fixing the unfixed image to the recording medium, wherein the image forming toner used for forming the visible image is the image forming toner described above. It is characterized by being.

According to the image forming apparatus of the present invention, an image forming toner that has excellent low-temperature fixability and heat-resistant storage stability even at a high speed and is fixed only at a desired position on a recording medium without causing an offset phenomenon is used. Therefore, even if the process line speed is high, an abnormal image is not generated and the image can be fixed stably. For example, if a tandem full-color image forming apparatus is used, a higher-quality image can be output at a higher speed. The image forming method and the image forming apparatus of the present invention can be widely applied to electrophotographic application fields using electrophotography (for example, electrostatic copying machines, laser beam printers, etc.).
In addition, since the above-described tandem image forming apparatus can transfer a plurality of toner images at a time, high-speed full-color printing is realized.

The image forming means as described above may be fixedly incorporated in the copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge.
The process cartridge is an apparatus (part) that contains an image carrier (photoconductor) and further includes a means selected from a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit. If necessary, other means such as a static elimination means may be included. There are many shapes and the like of the process cartridge, but a general example is the one shown in FIG. Here, the process cartridge includes a photosensitive member (101), and includes a charging unit (102), an exposure unit (103), a developing unit (104), and a cleaning unit (107). It has the means of. In the figure, reference numeral (105) denotes a recording medium (transfer body).

  That is, the process cartridge of the present invention includes an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and a formed static member. It is selected from developing means for developing the electrostatic latent image using image forming toner, transfer means for transferring the developed toner image to the recording medium, and cleaning means for removing the toner remaining on the surface of the image carrier after the transfer. A process cartridge which can be attached to and detached from an image forming apparatus main body integrated with at least one means, and the image forming toner used is the image forming toner of the present invention. It is. It should be noted that other means (for example, static elimination means) may be included as necessary as at least one means to be selected.

In the process cartridge of the present invention, since the image forming toner of the present invention is supplied from the developing unit, the fixing unit is stably fixed only at a desired position on the recording medium without causing an offset phenomenon due to an unfixed image. High quality images can be output. In addition, it is easy to store and transport and has excellent handling properties.

(Surface treatment of Pigment 1)
When the silica fine particles were treated on the pigment surface, a hybridizer NHS-0 type machine manufactured by Nara Machinery Co., Ltd. was used.
After weighing 1.5 g of silica fine particles (manufactured by Teika) and 30 g of rhodamine pigment (PR81, manufactured by Daido Kasei Co., Ltd.), stirring for 1 minute at the rotation speed of 1000 rpm with the premixer was repeated 5 times. It was. Thereafter, the main agitation was performed at a rotation speed of 8000 rpm for 10 minutes to subject the pigment to a surface treatment, and [Magenta Pigment 1] having silica fine particles fixed on the pigment surface was obtained.

(Production of polymerization toner 1)
(Synthesis of organic fine particle emulsion)
In a reaction vessel equipped with a stir bar and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 83 parts of styrene, 83 parts of methacrylic acid, When 110 parts of butyl acrylate and 1 part of ammonium persulfate were added and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours, and an aqueous vinyl resin (a copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). A dispersion [fine particle dispersion 1] was obtained. The average particle diameter of the [fine particle dispersion 1] measured by LA-920 (Laser diffraction / scattering particle size distribution measuring device manufactured by Horiba, Ltd.) was 105 nm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The weight average molecular weight of this resin was 150,000.

(Preparation of aqueous phase)
990 parts of water, 99 parts of [fine particle dispersion 1], 35 parts of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7: manufactured by Sanyo Chemical Industries) and 70 parts of ethyl acetate are mixed and stirred. A milky white liquid was obtained. This is designated as [Aqueous Phase 1].

(Synthesis of low molecular weight polyester)
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl Add 2 parts of tin oxide, react at 230 ° C for 8 hours at normal pressure, and further react for 5 hours under reduced pressure of 10-15 mmHg, then add 44 parts of trimellitic anhydride to the reaction vessel at 180 ° C at normal pressure. The mixture was reacted for 1.8 hours to obtain [Low molecular weight polyester 1]. [Low molecular polyester 1] had a number average molecular weight of 2500, a weight average molecular weight of 6700, and a peak molecular weight of 5000.

(Synthesis of intermediate polyester)
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 And 2 parts of dibutyltin oxide were added, reacted at 230 ° C. for 8 hours at normal pressure, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, Tg of 55 ° C., an acid value of 0.5, and a hydroxyl value of 51.

(Synthesis of Prepolymer 1)
Next, 410 parts of [intermediate polyester 1 ], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained.

(Synthesis of ketimine)
In a reaction vessel equipped with a stir bar and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1].

(Production of oil phase)
In a container equipped with a stirring rod and a thermometer, 160 parts of [low molecular weight polyester 1], 32 parts of carnauba wax and 400 parts of ethyl acetate were charged, heated to 80 ° C. with stirring, and maintained at 80 ° C. for 5 hours. Thereafter, it was cooled to 30 ° C. in 1 hour. Next, [Magenta Pigment 1] was added to the container so that the amount was 15 parts with respect to 100 parts by weight of the resin, and 40 parts of ethyl acetate was charged and mixed for 1 hour to obtain [Raw Material Solution 1] having a solid content of 50 wt%. .
[Material solution 1] 464 parts were transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), a liquid feed speed of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 0.5 mm zirconia beads were 80% by volume. The pigment and WAX were dispersed under the conditions of filling and 3 passes. Next, 420 parts of a 50% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1].

(Emulsification ⇒ Solvent removal)
[Pigment / WAX Dispersion 1] 885 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container and mixed for 1 minute at 5000 rpm with a TK homomixer (made by Tokushu Kika Co., Ltd.) After that, 1200 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at a rotational speed of 12500 rpm for 30 minutes to obtain [Emulsified Slurry 1].
[Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 35 ° C. for 7 hours, aging was carried out at 45 ° C. for 4 hours to obtain [Dispersion slurry 1]. In the middle of solvent removal, the sample was transferred to a TK homomixer and stirred at a rotational speed of 12,500 rpm for 40 minutes to deform the toner.

(Washing ⇒ drying)
[Dispersion Slurry 1] After 100 parts were filtered under reduced pressure, (1): 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (10 minutes at a rotation speed of 12,000 rpm), and then filtered. (2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. (3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered. (4): 300 parts of ion-exchanged water was added to the filter cake of (3), and the mixture was mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes) and then filtered twice to obtain [Filter cake 1].

(Preparation of base toner)
[Filter cake 1] was dried at 45 ° C. for 48 hours in a circulating drier, sieved with a mesh of 75 μm, and a charge control agent (salicylic acid metal salt E-84: 0.6 parts of (Orient Chemical Co., Ltd.) was mixed at 1000 rpm using a Henschel mixer, and then mixed at 5500 rpm with a Q-type mixer (Mitsui Kinzoku Kogyo Co., Ltd.) to fix the charge control agent on the toner surface. Base toner 1] was obtained.

(Addition of external additives)
Next, 100 parts of [base toner 1] was mixed with 0.7 parts of hydrophobic titanium oxide using a Henschel mixer to complete the production of [polymerized toner 1]. [Polymerized toner 1] had a weight average particle diameter (Dw) of 5.2 μm and a number average particle diameter (Dn) of 4.6 μm.

[Polymerized toner 2] was granulated in the same manner as in Example 1 except that [Pigment 2] was used in which the amount of silica fine particles used in the surface treatment of [Magenta Pigment 1] was changed to 4.5 g.

  [Polymerized toner 3] was granulated in the same manner as in Example 1, except that [Pigment 3] was used in which the amount of silica fine particles used in the surface treatment of [Magenta Pigment 1] was changed to 9.0 g.

The same procedure except that magenta pigment (PR57, manufactured by Toyo Ink Co., Ltd.) and [magenta pigment 4] in which the amount of silica fine particles used for the surface treatment was changed to 4.5 g was used instead of the magenta pigment PR81 used in Example 1. [Polymerized toner 4] was granulated by the method.

  The same procedure was used except that a yellow pigment (PY180, manufactured by Clariant) was used instead of the magenta pigment used in Example 1, and [Yellow Pigment 5] in which the amount of silica fine particles used for the surface treatment was changed to 4.5 g. [Polymerized toner 5] was granulated.

  In Example 1, [Polymerized toner 6] was granulated by the same method except that [Intermediate polyester 1] used in the production of the polymerized toner was not used.

  [Polymerized toner 7] was granulated in the same manner except that [Magenta pigment 7] in which the amount of silica fine particles used in Example 6 was changed to 9.0 g was used.

(Comparative Example 1)
[Polymerized toner 8] was granulated in the same manner as in Example 1 except that [Pigment 8] was used in which the amount of silica fine particles used in the surface treatment of [Magenta Pigment 1] was changed to 0 g.

(Comparative Example 2)
[Polymerized toner 9] was granulated in the same manner as in Example 1 except that [Magenta pigment 9] was used in which the amount of silica fine particles used in the surface treatment of [magenta pigment 1] was changed to 12 g.

(Comparative Example 3)
In Example 1, the surface treatment of [Magenta Pigment 1] was not performed. Instead, 30 parts of PR81 and 4.5 parts of silica fine particles were weighed without mixing and stirring into a beaker, and [Magenta Pigment 10] was added. Obtained. [Polymerized toner 10] was granulated in the same manner as in (Example 1) except that the entire amount of [Magenta pigment 10] was used instead of [Magenta pigment 9] used in Example 1.

(Comparative Example 4)
[Polymerized toner 11] was granulated in the same manner as in (Comparative Example 3) except that PR57 used in Example 4 was used instead of PR81 used in Comparative Example 3.

(Comparative Example 5)
[Polymerized toner 12] was granulated in the same manner as in (Comparative Example 3) except that PY180 used in Example 5 was used instead of PR81 used in Comparative Example 3.

The toners of the above examples and comparative examples were evaluated by the following methods. The evaluation results of Examples and Comparative Examples are shown in Tables 1 and 2.

(Method for measuring particle size of inorganic fine particles)
This was performed with a transmission electron microscope (TEM) H7000 manufactured by Hitachi High-Technologies Corporation. A small amount and an appropriate amount of the sample were placed on a micron grid (manufactured by Nissin EM Co.) covered with a predetermined coating film, and photographs were taken at an acceleration voltage of 100 kV and a magnification of 50,000 times. Next, the obtained image was binarized, and the average value of equivalent circle diameters determined from the area of 100 particles was taken as the particle diameter.

(Hydrophilicity inspection method)
In a 50 ml vial, 30 g of ion-exchanged water was added, then 0.15 g of a pre-weighed pigment was added and left for 1 hour. At this time, the pigment particles fell to the bottom of the vial, or the color that had been visually confirmed in the ion-exchanged water was judged to be hydrophilic.
When PR81 (manufactured by Daido Kasei Co., Ltd.), PR57 (manufactured by Toyo Ink Co., Ltd.), and PY180 (manufactured by Clariant Co.) used in Examples and Comparative Examples were examined for hydrophilicity by the above method, all were hydrophilic. there were.

(Inspection of elution into aqueous media)
The granulated aqueous solvent was put into a quartz cell having a layer thickness of 1 cm, and the transmittance at a spectral wavelength of 700 nm to 400 nm was measured with a V-650DS spectrophotometer manufactured by JASCO Corporation. At this time, when the yellow colorant had a transmittance of 450 nm and the magenta colorant had a transmittance of 550 nm of 80% or less, it was determined that the colorant was eluted.

(Image inspection)
Polymerized toners 1 to 12 obtained by the above method are mixed with the carrier used in imageo MP C4300 (manufactured by Ricoh) so that the toner concentration is 5%, and the resulting mixture is added to the magenta unit or yellow unit of the image forming apparatus. The developer weight was set to 180 g.
Using this developer, a monochrome image consisting only of magenta or yellow with an area ratio of 20% is output on an A4 size paper (T6000 70W T, manufactured by Ricoh) so that the toner amount is 0.45 mg / cm 2. Measure the chromaticity a * b * of the fixed image in the status A mode of X-Rite938 (X-Rite) and d50 light, and the saturation c * is the square root of the sum of the squares of a * and b *. Calculated from

(Toner pass / fail judgment)
In the elution test in an aqueous solvent, the magenta colorant was accepted if the transmittance at a wavelength of 550 nm was 80% or more and the chroma c * was 70 or more.
In addition, the yellow colorant was determined to pass if the transmittance at a wavelength of 450 nm was 80% or more and the chroma c * was 95 or more.

From the above results, [Polymerized Toner 1] to [Polymerized Toner 7] produced in (Example 1) to (Example 7) were judged as acceptable (O), but (Comparative Example 1) to (Comparative Example). [Polymerized toner 8] to [Polymerized toner 12] produced in 5) failed to satisfy the standard in either the elution into the aqueous solvent or the saturation and were judged as rejected (x). From the above, it was shown that the present invention is effective.

(About Figure 1)
DESCRIPTION OF SYMBOLS 10 Intermediate transfer body 14 Support roller 15 Support roller 16 Support roller 17 Cleaning device 18 Image forming unit 20 Image forming means 21 Exposure device 22 Secondary transfer device 24 Secondary transfer belt 23 Support roller 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Inversion device 30 Document base 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Photosensitive body 42 Paper feed roller 43 Paper bank 44 Paper feed cassette 45 Separation roller 46 Paper feed path 47 Conveyance roller 48 paper feed path 49 registration roller 51 manual feed tray 52 separation roller 53 manual paper feed path 55 switching claw 56 discharge roller 57 paper discharge tray 200 paper feed table 300 scanner 400 automatic document feeder (ADF)

Japanese Patent No. 2584450 Japanese Patent No. 4169943 Japanese Patent No. 4299084

Claims (11)

A toner having at least a binder resin and a colorant and granulated in an aqueous solvent,
The colorant, hydrophilic pigments or dyes are pigments and lake, and state, and are not allowed to fix the inorganic particles on the pigment surface, the inorganic fine particles, 5 weight per 100 parts by weight of pigment An image forming toner comprising 30 parts by weight or more . The image forming toner according to claim 1, wherein the inorganic fine particles have an average particle diameter of 10 nm to 100 nm. The inorganic fine particles, the image forming toner according to claim 1 or 2, characterized in that the silica fine particles having been hydrophobic-treated. The colorant, the image forming toner according to any one of claims 1 to 3, wherein the rhodamine dye is a pigment laked. One-component developer, comprising the toner for image formation according to any one of claims 1 to 4. Two-component developer, comprising the image forming toner and a carrier according to any one of claims 1 to 4. A charging step for charging at least the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the image carrier, and developing the electrostatic latent image with toner to form a visible image An image forming method comprising: a developing step, a transfer step of transferring the visible image onto a recording medium to form an unfixed image, and a fixing step of fixing the unfixed image on the recording medium, image forming method, wherein the toner used to form the visible image is an image forming toner according to any one of claims 1 to 4. The image forming method according to claim 7 , wherein a conveyance speed of the recording medium in the fixing step is 280 mm / second or more. At least an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the charged image carrier surface to form an electrostatic latent image, and the electrostatic latent image using toner Developing means for forming a visible image by developing, transfer means for transferring the developed toner image onto a recording medium to form an unfixed image, and fixing means for fixing the unfixed image to the recording medium an image forming apparatus including bets, toner used to form the visible image, an image forming apparatus which is a toner image formed according to any one of claims 1 to 4 . The image forming apparatus according to claim 9 , wherein a conveyance speed of the recording medium at the time of fixing by the fixing unit is 280 mm / second or more. An image carrier, a charging unit for charging the surface of the image carrier, an exposure unit for exposing the charged surface of the image carrier to form an electrostatic latent image, and the formed electrostatic latent image using toner At least one means selected from a developing means for developing, a transferring means for transferring the developed toner image to a recording medium, and a cleaning means for removing toner remaining on the surface of the image carrier after transfer is integrated with the image. a process cartridge which is detachably mountable to forming apparatus, a process cartridge in which the toner is the use, characterized in that it is an image forming toner according to any one of claims 1 to 4.

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