JP6205782B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus that is excellent in cleaning performance, noise and suppression of excessive toner consumption in an electrophotographic system including a cleaning device that removes residual toner and the like remaining on an intermediate transfer member. It is.

  In recent years, the use of image forming apparatuses such as electrophotographic copying machines has been expanded, and the market demand for image quality has been increasing. In office documents, in addition to the development of mapping technology and latent image formation technology for input, the types of character hieroglyphics are more abundant and finer at the time of output. Due to development, there is a demand for reproducibility of a latent image with extremely high image quality, which has few defects and unclearness in a printed image. In particular, with respect to high density images such as photographs, durability against line defects is required as disclosed in JP-A-2003-316035 and JP-A-2001-117418. Conventionally, this type of defect has been dealt with by improving the charge amount of the toner.

  In addition, as an electrophotographic digital full-color image forming apparatus, a plurality of image forming units having photosensitive drums or the like are provided according to the respective colors, and toner images of the respective colors formed on the respective photosensitive drums are supplied to a sheet of paper or The images are sequentially superimposed and transferred onto a transfer material such as an intermediate transfer belt. In the image forming apparatus having the transfer material conveyance belt as described above, the transfer material conveyance belt is contaminated with fog toner, toner scattered from the photosensitive drum, or the like. For this reason, a cleaning device having a cleaning blade as a cleaning member is provided in order to clean dirt on the transfer material conveyance belt. The cleaning blade is brought into contact with the conveyance belt with a predetermined pressure, and the transfer material conveyance belt is provided. The surface is scraped and cleaned. For this reason, many proposals have been made as cleaning means for the intermediate transfer member, and the cleaning performance is generally improved by adjusting the characteristics of the rubber material of the cleaning blade as disclosed in JP-A-2004-053956. I am trying.

On the other hand, with respect to the toner, the spherical shape and the small particle size of the toner are progressing from the viewpoint of improvement of development efficiency and dot reproducibility. Furthermore, the demand for oilless toner has been increased and commercialized in terms of improvement in uneven application of oil during fixing and downsizing of the fixing device.
On the other hand, the load on the cleaning blade is reduced as the toner development efficiency is improved, but the toner staying at the contact portion between the cleaning blade and the photoreceptor surface is reduced, and the friction coefficient between the cleaning blade and the photoreceptor surface is increased. , Stick slip is likely to occur. As a result, when a document with a small amount of toner consumption is continuously output, a noise may be generated at the blade portion. The squealing causes discomfort to the user and increases the durability of the blade by accelerating the deterioration of the blade, causing problems such as poor cleaning. As disclosed in Japanese Patent Application Laid-Open No. 2007-94240 and Japanese Patent Application Laid-Open No. 2004-163807, the above problem has been addressed by improving the surface composition of conventional OPC and adding a lubricating component to the toner external additive.

JP2003-316035 JP 2001-117418 A JP 2004-053956 A JP2007-094240 JP2004-163807

  However, even when these techniques are used, with the conventional transfer material conveyance belt cleaning blade, the probability of occurrence of poor cleaning of the transfer material conveyance belt increases with the spheroidization and particle size reduction of the toner. In an electrophotographic process that is larger than a conventional electrophotographic process such as a machine, a cleaning defect occurs at the end of the transfer material conveyance belt, and stains occur on the image as line defects. In addition, the cleaning performance on the transfer material conveying belt is improved by reducing the toner shape to a lower circularity and larger particle size than conventional ones, but the toner consumption deteriorates as the transfer efficiency decreases. . Further, the addition of silicone oil-treated silica improves toner consumption, but increases friction between the electrophotographic photosensitive member and the photosensitive member cleaning blade that removes residual toner on the electrophotographic photosensitive member. As a result, the stick-slip phenomenon of the photoconductor cleaning blade is induced to generate noise.

  In this way, all requirements such as suppression of line defects due to poor cleaning on the transfer material conveyance belt, good toner consumption, and suppression of noise between the electrophotographic photosensitive member and the cleaning blade for the photosensitive member are met. It was difficult to achieve both.

  As a result of intensive studies in view of the above problems, the present inventors have determined that, in a toner having a specific volume average particle diameter, the toner has a specific amount of silicone oil-treated silica and higher fatty acid metal salt particles, so that the transfer material is conveyed. We have found that it is possible to achieve both improved belt cleaning performance, good toner consumption, and suppression of noise noise between the electrophotographic photosensitive member and the photosensitive member cleaning blade.

That is, the gist of the present invention resides in the following [1].
[1] An electrophotographic photosensitive member carrying a toner image and a volume average particle size of 6. An integrated electrophotographic cartridge having toner base particles having a particle size of 7 μm or more and 7.5 μm or less and an electrostatic charge image developing toner having an external additive, and a transferable transfer of a toner image formed on the electrophotographic photosensitive member In the image forming apparatus comprising a transfer material transport body, a transfer material transport body cleaning member for removing toner remaining on the surface of the transfer material transport body, and a photoconductor cleaning blade , the transfer material transport body The cleaning member is a cleaning blade, and the length of the transfer material transport body cleaning blade in the long axis direction is 32 cm or more and 95 cm or less, and the electrostatic image developing toner is any of (1) and (2) below. An image forming apparatus characterized by satisfying.
(1) 0.15 parts by mass or more and 0.30 parts by mass or less of a higher fatty acid metal salt with respect to 100 parts by mass of the toner base particles (2) Silicone oil treatment is performed on 100 parts by mass of the toner base particles. The silica is 1.4 parts by mass or more and 1.8 parts by mass or less, and the amount of all external additives used is 1.0 part by mass or more and 2.4 parts by mass or less with respect to 100 parts by mass of the toner base particles.

According to the present invention, the poor cleaning of the residual toner on the transfer material conveyance body and the sound noise between the electrophotographic photosensitive member and the photosensitive member cleaning blade are simultaneously suppressed well, and the toner consumption is improved. An image forming apparatus can be provided.
In addition, the present invention provides the above effect when the image forming apparatus has a large electrophotographic process in which the length in the major axis direction of the transfer material conveying cleaning blade of A3 machine is 32 cm or more and 95 cm or less. Demonstrate more prominently.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating a configuration of a main part of an embodiment of a transfer material transport body used in the image forming apparatus of the present invention.

  An image forming apparatus according to the present invention includes an electrophotographic photosensitive member on which a toner image is carried and an electrostatic charge image developing toner having toner base particles having a volume average particle diameter of 6.5 μm or more and 7.5 μm or less. An electrophotographic cartridge, a movable transfer material transport body for transferring a toner image formed on the electrophotographic photosensitive member, and a transfer material transport body cleaning member for removing toner remaining on the surface of the transfer material transport body; <1. As described in detail in Toner for developing electrostatic image>, the toner for developing electrostatic image has the specific amount of fatty acid metal salt and silica treated with silicone oil, and thus the effects of the present invention are exhibited. The effect of the present invention is <2-1. As will be described in detail in <Transfer Material Conveying Body and Image Forming Apparatus>, it is remarkably exhibited when the length of the cleaning member for the transfer material conveying body in the major axis direction is 32 cm or more.

<1. Toner for electrostatic image development>
Hereinafter, the electrostatic image developing toner used in the image forming apparatus of the present invention will be described. However, the toner used in the present invention is not limited to the following embodiment, and may be modified arbitrarily. Can do.
The method for producing the electrostatic image developing toner used in the present invention (hereinafter sometimes abbreviated as “developing toner” or “toner”) is not particularly limited. In the toner manufacturing method, the configuration described below may be employed.

[1-1. Toner Configuration]
Examples of components constituting the toner used in the present invention include toner base particles and external additives. The toner base particles include a binder resin and a colorant (pigment), as well as a charge control agent and a wax as necessary. Contains internal additives such as In particular, in the present invention, the toner base particles have a volume average particle diameter of 6.5 μm or more and 7.5 μm or less, and 0.15 mass of higher fatty acid metal salt particles is added to 100 parts by mass of the toner base particles. Part or more and 0.30 parts by mass or less, and a toner having 1.30 parts by mass or more and 1.60 parts by mass or less of silica-treated silica.

<Toner particle size>
In the present invention, the lower limit of the volume average particle diameter of the toner base particles is 6.5 μm or more, and preferably 6.7 μm or more from the viewpoint of improving the cleaning property on the transfer material conveying belt. On the other hand, the upper limit is 7.5 μm or less, and from the viewpoint of suppressing toner consumption, it is preferably 7.3 μm or less.

<Higher fatty acid metal salt particles>
The lower limit of the amount of the higher fatty acid metal salt particles added relative to 100 parts by mass of the toner base particles is 0.15 parts by mass or more, and preferably 0.20 parts by mass or more from the viewpoint of suppressing noise. On the other hand, the upper limit is 0.30 parts by mass or less, preferably 0.27 parts by mass or less, and more preferably 0.25 parts by mass or less from the viewpoint of suppressing toner consumption.

Examples of the higher fatty acid metal salt particles include metal stearates such as zinc stearate and calcium stearate, and metal laurates such as zinc laurate and calcium laurate. Among these, metal stearate is preferred from the viewpoint of good heat resistance of metal salt particles, ease of production, and easy handling, and zinc stearate that is particularly effective is more preferred. preferable.
The volume average particle diameter of the higher fatty acid metal salt particles is not particularly limited as long as the effects of the present invention are not significantly impaired, but the lower limit is usually 70 nm or more, preferably 80 nm or more. On the other hand, the upper limit is usually 110 nm or less, preferably 100 nm or less.

<Silicone oil-treated silica>
The lower limit of the addition amount of the silicone oil-treated silica to 100 parts by mass of the toner base particles is 1.4 parts by mass or more, preferably 1.5 parts by mass or more. From the viewpoint of improving the fluidity of the toner and suppressing consumption. More preferably, it is 1.6 parts by mass or more. On the other hand, the upper limit is 2.0 parts by mass or less, and more preferably 1.8 parts by mass or less from the viewpoint of contamination of the cartridge member and suppression of filming.

As the silicone oil-treated silica, known silica can be used. However, silica that has been treated with a silicone compound or a silicone-based treating agent may be used because higher hydrophobicity can be imparted .

The specific surface area value according to the BET method of the silicone oil-treated silica is not particularly limited as long as the effects of the present invention are not significantly impaired, but the lower limit is usually 70 m ² / g or more, preferably 80 m ² / g or more. is there. On the other hand, an upper limit is 130 m < ² > / g or less normally, Preferably it is 120 m < ² > / g or less.

<Other toner configurations>
As binder resin, polystyrene resin, epoxy resin, polyester resin, polyamide resin, styrene acrylic resin, styrene methacrylate resin, polyurethane resin, vinyl resin, polyolefin resin, styrene butadiene resin, phenol resin, polyethylene resin, silicon resin, butyral resin Terpene resin, polyol resin and the like.

  A known colorant can be arbitrarily used as the colorant. Specific examples of the colorant include carbon black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo, Any known dyes and pigments such as disazo dyes and condensed azo dyes can be used alone or in combination. In the case of a full color toner, it is preferable to use benzidine yellow for yellow, monoazo and condensed azo dyes, magenta for quinacridone and monoazo dyes, and cyan for phthalocyanine blue. The colorant is preferably used so as to be 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer primary particles.

  A charge control agent may be used for the toner. When the charge control agent is used, any known one can be used alone or in combination. For example, a quaternary ammonium salt as a positively chargeable charge control agent, Examples include basic and electron-donating metal substances, and as negatively chargeable charge control agents, metal chelates, metal salts of organic acids, metal-containing dyes, nigrosine dyes, amide group-containing compounds, phenol compounds, naphthol compounds, and their Examples thereof include metal salts, urethane bond-containing compounds, and acidic or electron-withdrawing organic substances.

In addition, when used as a toner other than a black toner in a color toner or a full color toner, it is preferable to use a charge control agent that is colorless or light in color and does not disturb the color tone of the toner. For example, as a positively chargeable charge control agent, A quaternary ammonium salt compound is a negatively chargeable charge control agent such as a metal salt or metal complex of salicylic acid or alkylsalicylic acid with chromium, zinc or aluminum, a metal salt of benzylic acid, a metal complex, an amide compound, a phenol compound, Hydroxylnaphthalene compounds such as naphthol compounds, phenolamide compounds, and 4,4′-methylenebis [2- [N- (4-chlorophenyl) amide] -3-hydroxynaphthalene] are preferred.

  The toner used in the present invention may contain a wax for imparting releasability. Any wax can be used as long as it has releasability. Specifically, for example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate Plant-based waxes such as hydrogenated castor oil and carnauba wax; ketones having long-chain alkyl groups such as distearyl ketone; silicones having alkyl groups; higher fatty acids such as stearic acid; long-chain fatty alcohols such as eicosanol; glycerin; Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as pentaerythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amide and stearic acid amide; low molecular weight polyesters.

  Among these waxes, in order to improve fixability, the wax preferably has a melting point of 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, the thing of 100 degrees C or less is preferable, the thing of 90 degrees C or less is more preferable, and 80 degrees C or less is especially preferable. A wax having a melting point within the above range exhibits excellent fixability at low temperatures without causing stickiness or the like.

  The waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner. The amount of the wax is preferably 1 part by mass or more per 100 parts by mass of the toner, more preferably 2 parts by mass or more, and further preferably 5 parts by mass or more. Moreover, it is preferable that it is 40 mass parts or less, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less. If the wax content in the toner is too low, performance such as high-temperature offset may not be sufficient. If it is too high, the anti-blocking property may be insufficient or the wax may leak from the toner and contaminate the device. There is a case.

[1-2. Method for producing toner for developing electrostatic image]
Next, a method for producing the electrostatic image developing toner used in the present invention will be described.
(1-2-1. Manufacturing Process of Toner Base Particles)
The method for producing the toner of the present invention is not limited, and the toner base particles can be produced by a conventionally used method such as a pulverization method, a wet method, a method of sphering the toner by a mechanical impact force, heat treatment, or the like. Examples of the wet method include a suspension polymerization method, an emulsion polymerization aggregation method, a dissolution suspension method, and an ester extension method.

1-2-1-1. Pulverization Method A method for producing toner base particles by the pulverization method will be described. In the case of the pulverization method, a predetermined amount of a binder resin, a colorant, and other components as required are mixed and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.

  Next, each component is blended, and the mixed toner raw material is melt-kneaded to melt the resins and disperse the colorant and the like therein. In the melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. For the kneading machine, a single-screw or twin-screw extruder is used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by K.C.K. , Bus Co., Ltd. co-kneader. Furthermore, the colored resin composition obtained by melt-kneading the toner raw material is rolled by a two-roll roll after melt-kneading, and then cooled through a cooling step of cooling by water cooling or the like.

  The cooled product of the colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, first, coarse pulverization is performed with a crusher, a hammer mill, a feather mill or the like, and further, pulverization is performed with a kryptron system manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nisshin Engineering Co., Ltd. or the like. After that, if necessary, the particles are classified using a classifier such as an inertia classification type elbow jet (manufactured by Nippon Steel Mining Co., Ltd.) or a centrifugal classification type turboplex (manufactured by Hosokawa Micron Co., Ltd.). obtain. Further, the toner may be spheroidized using a conventionally used method.

1-2-1-2. Wet Method In the present invention, it is preferable to apply a wet method for producing toner mother particles in a wet medium. Examples of the wet method include suspension polymerization method, emulsion polymerization aggregation method, dissolution suspension method and the like, and any method may be used. Is preferred.

(Suspension polymerization method)
In the suspension polymerization method, a colorant, a polymerization initiator, and, if necessary, additives such as wax, polar resin, charge control agent and cross-linking agent are added to the binder resin monomer and dissolved or dispersed uniformly. A monomer composition is prepared. This monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, polymerization is performed by stirring to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. By collecting these by washing and filtration, toner mother particles can be obtained.

(Dissolution suspension method)
In the dissolution suspension method, a solution phase obtained by dissolving a binder resin in an organic solvent and adding a colorant or the like is dispersed by a mechanical shear force in an aqueous phase containing a dispersant and the like to form droplets. The toner base particles can be obtained by forming and removing the organic solvent from the droplets.
(Emulsion polymerization aggregation method)
In the emulsion polymerization aggregation method, polymer primary particles of a binder resin monomer obtained by an emulsion polymerization step, a colorant dispersion, a wax dispersion, etc. are prepared, and these are dispersed in an aqueous medium and heated. By performing the agglomeration step and further the aging step. These can be collected by washing and filtration to obtain toner base particles. Next, the toner base particles go through a drying process. Further, if necessary, an external additive or the like can be added to the toner base particles to obtain a toner.

  The emulsion polymerization aggregation method will be described in more detail. In the emulsion polymerization step, a polymerizable monomer that becomes a binder resin is usually polymerized in an aqueous medium in the presence of an emulsifier. At this time, each monomer is used to supply the polymerizable monomer to the reaction system. The body may be added separately, or a plurality of types of monomers may be mixed in advance and added simultaneously. The monomer may be added as it is, or may be added as an emulsion mixed and adjusted in advance with water or an emulsifier.

As the acidic monomer, a polymerizable monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, a polymerizable monomer having a sulfonic acid group such as sulfonated styrene, Examples thereof include polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide. Examples of the basic monomer include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocyclic-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. And (meth) acrylic acid ester having an amino group. These acidic monomers and basic monomers may be used singly or as a mixture of a plurality of types, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, more preferably acrylic acid and / or methacrylic acid.

The total amount of the acidic monomer and the basic monomer in 100 parts by mass of the total polymerizable monomers constituting the binder resin is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass. More preferably, it is 1.0 part by mass or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less.
Examples of other polymerizable monomers include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, and pn-nonylstyrene, methyl acrylate, Acrylic esters such as ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate -Methacrylic acid esters such as butyl, isobutyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylic De, N, N-dibutyl acrylamide, and the like, the polymerizable monomer may be used singly, or may be used in combination.

  The electrostatic charge developing toner of the present invention comprises a styrene resin as a binder resin, which is a polymer of a styrene monomer alone or a polymer of a styrene monomer and another monomer. According to the present invention, even if the resin contains a styrene resin as a binder resin, it is contained in the toner so that the value obtained by dividing the styrene concentration measured by the method of the present invention by the ethylbenzene concentration is 5 or less. The concentration of volatile organic compounds can be reduced. For example, the value obtained by dividing the styrene concentration of the commercial toner measured by the method of the present invention by the ethylbenzene concentration is 15 or more, and a toner using a styrene resin as a binder resin by the method of the present invention. In addition, the content of volatile organic compounds such as styrene can be reduced.

  Furthermore, when the binder resin is a cross-linked resin, a polyfunctional monomer having radical polymerizability is used together with the above polymerizable monomer, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, Examples include diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, and diallyl phthalate. It is also possible to use a polymerizable monomer having a reactive group in a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein and the like. Among these, radically polymerizable bifunctional polymerizable monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable. These polyfunctional polymerizable monomers may be used alone or as a mixture of plural kinds.

When the binder resin is polymerized by emulsion polymerization, a known surfactant can be used as an emulsifier. As the surfactant, one or more surfactants selected from cationic surfactants, anionic surfactants, and nonionic surfactants can be used in combination.
Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, and examples of the anionic surfactant include And fatty acid soap such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate and the like. Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene monohexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose Etc.

The amount of the emulsifier used is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer. In addition, these emulsifiers can be used as protective colloids, for example, one or more of partially or completely saponified polyvinyl alcohols such as polyvinyl alcohol and cellulose derivatives such as hydroxyethyl cellulose.
The volume average particle diameter of the polymer primary particles obtained by emulsion polymerization is preferably 0.02 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, preferably 3 μm or less, more preferably 2 μm. Hereinafter, it is more preferably 1 μm or less. If the particle size is too small, it may be difficult to control the aggregation rate in the aggregation process. If it is too large, the particle size of the toner particles obtained by aggregation tends to be large, and a toner having the target particle size is obtained. May be difficult.

  In the emulsion polymerization suspension method, known polymerization initiators can be used as necessary, and the polymerization initiators can be used alone or in combination of two or more. For example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, and the like, and redox initiators combining these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide, 4,4 '-Azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, and other water-soluble polymerization initiators, and these water-soluble polymerization initiators as a component combined with a reducing agent such as ferrous salt Redox initiator systems, benzoyl peroxide, 2,2′-azobis-isobutyronitrile, and the like are used. These polymerization initiators may be added to the polymerization system before, simultaneously with the addition of the monomer, or after the addition, and these addition methods may be combined as necessary.

Moreover, a well-known chain transfer agent can be used as needed, and specific examples include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, carbon tetrachloride, trichlorobromomethane and the like. The chain transfer agent may be used alone or in combination of two or more, and is used in an amount of 0 to 5% by mass based on the polymerizable monomer.
Moreover, a well-known suspension stabilizer can be used as needed. Specific examples of the suspension stabilizer include calcium phosphate, magnesium phosphate calcium hydroxide, magnesium hydroxide and the like. These may be used alone or in combination of two or more, and may be used in an amount of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

The polymerization initiator and the suspension stabilizer may be added to the polymerization system at any time before, simultaneously with, or after the addition of the polymerizable monomer, and these addition methods are combined as necessary. May be.
In addition, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, and the like can be appropriately added to the reaction system.

  The blending of the colorant in the emulsion polymerization aggregation method is usually performed in an aggregation step. A dispersion of polymer primary particles and a dispersion of colorant particles are mixed to form a mixed dispersion, which is then aggregated to form a particle aggregate. The colorant is preferably used in the state of being dispersed in water in the presence of an emulsifier, and the volume average particle diameter of the colorant particles is preferably 0.01 μm or more, more preferably 0.05 μm or more, preferably 3 μm or less. More preferably, it is 1 μm or less.

When a charge control agent is contained in the toner using the emulsion polymerization aggregation method, the charge control agent is added together with the polymerizable monomer during emulsion polymerization, or added in the aggregation step together with the polymer primary particles and the colorant. Or it can mix | blend by methods, such as adding after polymer primary particle, a colorant, etc. are aggregated and it becomes the target particle diameter substantially. Among these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average particle size of 0.01 μm or more and 3 μm or less.

  The aggregation step in the emulsion polymerization aggregation method is performed in a tank equipped with a stirrer, and there are a method of heating, a method of adding an electrolyte, and a method of combining these. When polymer primary particles are aggregated with stirring to obtain particle aggregates of the desired size, the particle size of the particle aggregate is controlled from the balance between the cohesive force between the particles and the shearing force by stirring. However, the cohesive force can be increased by heating or adding an electrolyte.

When aggregation is performed by adding an electrolyte, both an organic salt and an inorganic salt can be used as the electrolyte. Specifically, as the electrolyte, NaCl, KCl, LiCl, Na ₂ S
O ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na and the like. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

  The amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more with respect to 100 parts by mass of the solid component of the mixed dispersion. preferable. Further, it is preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When the addition amount is in the above range, the agglomeration reaction can be rapidly advanced, and the particle size can be controlled relatively easily without causing fine powder or an irregular shape after the agglomeration reaction. Particle aggregates having an average particle size can be obtained. The aggregation temperature in the case of performing aggregation by adding an electrolyte is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, preferably 70 ° C. or lower, more preferably 60 ° C. or lower.

  The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is preferably (Tg-20) ° C. or higher, and more preferably (Tg-10) ° C. or higher, where Tg is the glass transition temperature of the polymer primary particles. . Moreover, Tg or less is preferable and (Tg-5) degrees C or less is still more preferable. The time required for agglomeration is optimized depending on the shape of the apparatus and the processing scale, but in order for the toner particle size to reach the target particle size, it is usually held at the predetermined temperature for at least 30 minutes. desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.

  If necessary, particles having adhered or fixed resin particles may be formed on the surface of the particle aggregate after the aggregation treatment. In some cases, the chargeability and heat resistance of the obtained toner can be improved by attaching or fixing the resin particles whose properties are controlled to the surface of the particle aggregate, and further, the effects of the present invention can be made more remarkable. . When resin particles having a glass transition temperature higher than that of the polymer primary particles are used as the resin particles, it is preferable because blocking resistance can be further improved without impairing fixing properties. The volume average particle size of the resin particles is preferably 0.02 μm or more, and more preferably 0.05 μm or more. Moreover, 3 micrometers or less, Furthermore, 1.5 micrometers or less are preferable. As the resin particles, those obtained by emulsion polymerization of monomers similar to the polymerizable monomers used for the above-mentioned polymer primary particles can be used.

  Resin particles are usually used as a dispersion dispersed in water or a liquid mainly composed of water using a surfactant. However, when a charge control agent is added after the aggregation treatment, charge control is performed on the dispersion containing particle aggregates. It is preferable to add the resin particles after adding the agent. In order to increase the stability of the particle aggregate obtained in the aggregation step, it is preferable to perform fusion in the aggregated particles in the aging step after the aggregation step.

In the emulsion polymerization aggregation method, the temperature of the aging step after the aggregation step is preferably at least Tg of the polymer primary particles, more preferably at least 5 ° C higher than Tg, and preferably Tg. The temperature is 80 ° C. or higher, more preferably 50 ° C. or lower than Tg. The time required for the aging step varies depending on the shape of the target toner, but is preferably 0.1 to 10 hours, more preferably 1 to 6 hours after reaching the glass transition temperature of the polymer primary particles. To do.

  In addition, it is preferable to add a surfactant or raise the pH value after the aggregation process, preferably before the aging process or during the aging process. As the surfactant used here, one or more emulsifiers can be selected from the emulsifiers that can be used when producing the polymer primary particles. In particular, the emulsifiers used when producing the polymer primary particles. It is preferable to use the same. Although the addition amount in the case of adding surfactant is not limited, Preferably it is 0.1 mass part or more with respect to 100 mass parts of solid components of a mixed dispersion liquid, More preferably, it is 1 mass part or more, More preferably, it is 3 masses. It is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less. After the aggregation process, before the completion of the ripening process, by adding a surfactant or raising the pH value, it is possible to suppress aggregation of the particle aggregates aggregated in the aggregation process, In some cases, the generation of coarse particles can be suppressed.

  By heat treatment in the aging step, the polymer primary particles in the aggregate are fused and integrated, and the toner particle shape as the aggregate becomes close to a spherical shape. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner base particles can be made nearly spherical. According to such a ripening step, by controlling the temperature and time of the ripening step, toner mothers having various shapes such as a shape in which the polymer primary particles are aggregated, a spherical shape in which the fusion has progressed, and the like have been performed. Particles can be obtained.

Toner base particle washing step Toner base particles obtained by a wet method such as suspension polymerization, emulsion polymerization aggregation, dissolution suspension method, etc. are obtained by solid-liquid separation of the toner base particles obtained from the wet medium. It is preferable that the toner base particles are collected as particle aggregates and then washed as necessary.
As the liquid used for cleaning, water having a higher purity than the wet medium in which the toner is immersed in the final step of the wet method may be used, or an aqueous solution of acid or alkali may be used. As the acid, inorganic acids such as nitric acid, hydrochloric acid and sulfuric acid, and organic acids such as citric acid can be used. As the alkali, soda salts (sodium hydroxide, sodium carbonate, etc.), silicates (sodium metasilicate, etc.), phosphates, etc. can be used. Cleaning can also be performed by heating to room temperature or about 30 to 70 ° C.

  From the toner mother particles, the suspension stabilizer, the emulsifier, the wet medium, the unreacted residual monomer, the toner having a small particle diameter, and the like are removed by the washing step. After the washing step, the toner base particles are preferably obtained in a wet cake state by filtration or decantation. This is because the handling becomes easy in the subsequent process. The washing process may be repeated a plurality of times.

○ Moisture removal step of toner base particles The method for producing a toner for developing an electrostatic charge according to the present invention preferably includes a step of removing the water content of the toner base particles to 0.4% by mass or less before the drying step described later. . Since the wet cake-like toner base particles after the washing step are in a wet state, the water content in the toner base particles is 50% by weight or less, more preferably 40% by weight or less, with respect to 100% by weight of the toner base particles. More preferably, it is 30 mass% or less. The wet mother toner particles are evaporated in advance until the water content becomes 0.4% by mass or less, whereby a volatile organic compound contained in the toner mother particles in the subsequent drying step. Can be efficiently diffused.

As the dryer used in the moisture removal step, a fluid dryer, a jet dryer, a vacuum dryer, or the like can be used. The latent heat of moisture evaporation is directly applied to the toner base particles to increase the moisture removal rate. For this reason, it is preferable to use a fluidized drier in which gas is introduced and dried. For example, a fluidized dryer with a vibration device described later can be used, and a fluidized dryer without a vibration device can also be used. It is more preferable to use a fluidized dryer without a vibration device. The gas applied to the fluidized dryer used in the moisture removal process, the temperature of the gas, the temperature of the dryer, etc. are the gas applied to the fluidized dryer with vibrator used in the drying process described later, the temperature of the gas, the temperature of the dryer Etc., and similar gases and conditions can be applied.

○ Drying step of toner base particles In the step of drying the toner base particles, a dryer such as a fluid dryer, a jet dryer, or a vacuum dryer can be used. Of these, drying with a fluidized dryer equipped with a vibration device is preferred. The fluidized dryer with a vibration device can quickly dry the toner base particles by using the latent heat of vaporization of the water contained in the toner base particles by flowing a gas into the main body of the dryer. In addition, by applying vibration to the toner base particles with a vibration device, the toner base particles can be fluidized even if the gas flow rate is reduced, and the aggregates gathered in the lower part are crushed and quickly and efficiently. Thus, the toner base particles can be dried.

Drying is preferably performed under normal pressure or reduced pressure. Under reduced pressure, the amount of heat that can be given to the toner base particles by the gas becomes small. Therefore, drying at normal pressure is more preferable.
(1-2-2. Toner Formation Step)
Next, an external additive is added to the toner base particles, and the external additive is adhered or fixed to the surface of the toner base particles to form a toner. By adding external additives, OPC (organic
photoconductors) filming and transfer efficiency can be improved.

As the external additive added here, the above-mentioned <higher fatty acid metal salt particles> and <silicone oil-treated silica> may be used, and other external additives may be appropriately added.
Other external additives include, for example, titanium oxide, aluminum oxide (alumina), zinc oxide, tin oxide, barium titanate, strontium titanate, hydrotalcite and the like as inorganic particles, and organic particles such as methacrylic acid. Examples thereof include organic resin particles such as acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, and styrene-acrylic acid ester copolymer particles.

The volume average particle diameter of other external additives other than <higher fatty acid metal salt particles> and <silicone oil-treated silica> is not particularly limited as long as the effects of the present invention are not significantly impaired, but the lower limit is usually 5 nm or more. Preferably, it is 10 nm or more. On the other hand, the upper limit is usually 350 nm or less, preferably 300 nm or less.
The amount of all external additives used is not particularly limited, but the amount of all external additives used is usually 1.0 parts by mass or more and 1.1 parts by mass or more with respect to 100 parts by mass of toner base particles. It is preferably 4 parts by mass or less, and more preferably 2.3 parts by mass or less. If the amount used is too small, the coverage on the surface of the toner base particles decreases, and the wax in the vicinity of the surface may be fused to reduce the caking property (heat resistant storage stability) in a high temperature and high humidity environment. On the other hand, if the amount is too large, it may cause image defects due to missing of the cleaning blade due to excessive fluidity, and poor fixability due to suppression of exudation of wax from the toner inside.

As a method for adding the external additive to the toner base particles, a method in which the external additive is added to the system charged with the toner base particles and mixed by stirring is used. For the stirring and mixing of the toner base particles and the external additive, it is preferable to use a mechanical rotary processing device, and specifically, a rotary mixer such as a Henschel mixer is preferably used.
As the speed (peripheral speed) of the tip of the stirring blade in the addition treatment by such an apparatus, 2
The stirring is preferably performed at a stirring speed of 1.2 to 95.5 m / sec, preferably 38.2 to 76.4 m / sec. By adjusting the rotation speed, it is possible to adjust the embedding of the external additive in the colored particles by this stirring and mixing treatment, and as a result, the fluidity of the obtained toner can be controlled.

Further, in the toner used in the present invention, it is preferable that the external additive is uniformly attached to the surface of the toner particles. However, a plurality of particles having different particle sizes (hereinafter referred to as “multiple diameter particles”) are also used. When the external additive is used in combination as an external additive, the external additive can be uniformly adhered to the surface of the toner particles by mixing each external additive by two or more stages of mixing. It is preferable to use a multistage mixing method in which a small particle size external additive is added and mixed, and then a large particle size external additive is added and mixed.
The stirring time for the stirring and mixing process can be determined according to the stirring speed and the like.
As temperature which adds an external additive, 25 to 55 degreeC is preferable and 30 to 50 degreeC is more preferable.

[1-3. Properties of toner]
The average circularity of the toner used in the present invention is preferably 0.955 or more, and more preferably 0.960 or more. Moreover, it is preferable that it is 0.990 or less, and it is more preferable that it is 0.985 or less. When the average circularity of the toner is within the above range, a good image can be formed.

<2. Transfer Material Carrier, Electrophotographic Cartridge, and Image Forming Apparatus>
Next, an embodiment of an image forming apparatus having a transfer material conveyance body and using an electrophotographic cartridge will be described with reference to FIGS. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

<2-1. Transfer material carrier and image forming apparatus>
A main configuration of an image forming apparatus having a transfer material transport member according to the present invention will be described with reference to FIG.
As shown in FIG. 1, the image forming apparatus of the present invention includes a transfer material transport body 1, and a transfer material transport body cleaning blade 2 is provided along the transfer material transport body 1. Clean the remaining toner.

Here, when the overall length in the longitudinal direction of the transfer material transport body cleaning blade 2 installed on the transfer material transport body 1, as represented by the A3 machine and other large printing presses, is 32 cm or more, at the end. Since the contact pressure between the blade and the transfer material transport body is weaker than that in the central portion, a cleaning failure is likely to occur at the end of the transfer material transport body. The present invention is applied when the transfer material transport body cleaning blade 2 installed in the transfer material transport body 1 has a total length in the longitudinal direction of 32 cm or more, and thereby exhibits the effects of the present invention more remarkably. The overall length in the longitudinal direction of the transfer material conveying member cleaning blade 2 is preferably 35 cm or more. The upper limit of the overall length in the longitudinal direction of the transfer material conveying member cleaning blade 2 is usually 95 cm or less.
Further, the image forming apparatus includes an electrophotographic toner cartridge 3, an exposure unit 4, a transfer device 5 and a fixing device 6.

The electrophotographic cartridge 3 develops the toner T on the transfer material transport body 1, and FIG. 1 shows a toner cartridge having an electrophotographic photosensitive member as an example.
The exposure device 4 is not particularly limited as long as it can expose the electrophotographic photosensitive member of the electrophotographic cartridge 3 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. . Among these, it is preferable to use light having a short wavelength of 380 to 500 nm because the resolution becomes high. Among these, 405 nm monochromatic light is preferable.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 is disposed to face the transfer material transport body 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the transfer material transport body 1 onto a recording paper (paper, medium) P. Is.

When the toner transferred onto the recording paper P passes between the upper fixing member 61 and the lower fixing member 62 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

<2-2. Electrophotographic toner cartridge>
The construction of the main part of the electrophotographic toner cartridge used in the image forming apparatus will be described with reference to FIG.
As shown in FIG. 2, the electrophotographic toner cartridge includes an electrophotographic photosensitive member 31, a photosensitive member cleaning blade 32, a charging device 33, an exposure device 4, and a developing device 34, and further transfers as necessary. A device 35 is provided.

  The electrophotographic photosensitive member 31 is not particularly limited as long as it is an electrophotographic photosensitive member. In FIG. 2, for example, a drum-shaped photosensitive member in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support is used. Show. A photoconductor cleaning blade 32, a charging device 33, an exposure device 4, a developing device 34, and a transfer device 35 are arranged along the outer peripheral surface of the electrophotographic photoconductor 31.

  The charging device 33 charges the electrophotographic photoreceptor 31 and uniformly charges the surface of the electrophotographic photoreceptor 31 to a predetermined potential. Examples of the charging device include a corona charging device such as a corotron and a scorotron, a direct charging device (contact type charging device) that charges a direct charging member to which a voltage is applied by contacting the photosensitive member surface, and a contact type charging device such as a charging brush. Often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 2, a roller-type charging device (charging roller) is shown as an example of the charging device 33. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

  The type of the developing device 34 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 2, the developing device 34 includes a developing tank 341, an agitator 342, a supply roller 343, a developing roller 344, and a regulating member 345, and is configured to store toner T inside the developing tank 341. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 34 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 343 is formed from a conductive sponge or the like. The developing roller 344 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 344 may be smoothed or roughened as necessary.
The developing roller 344 is disposed between the electrophotographic photosensitive member 31 and the supply roller 343 and is in contact with the electrophotographic photosensitive member 31 and the supply roller 343, respectively. The supply roller 343 and the developing roller 344 are rotated by a rotation drive mechanism (not shown). The supply roller 343 carries the stored toner T and supplies it to the developing roller 344. The developing roller 344 carries the toner T supplied by the supply roller 343 and contacts the surface of the electrophotographic photoreceptor 31.

  The regulating member 345 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such metal blade with a resin. The regulating member 345 contacts the developing roller 344 and is pressed against the developing roller 344 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulation member 345 may be provided with a function of imparting charge to the toner T by frictional charging with the toner T.

The agitator 342 is rotated by a rotation drive mechanism, and agitates the toner T and conveys the toner T to the supply roller 343 side. A plurality of agitators 342 may be provided with different blade shapes and sizes.
The photoconductor cleaning blade 32 is not particularly limited, and any cleaning device such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, or a blade cleaner can be used. The photoconductor cleaning blade 32 scrapes residual toner adhering to the photoconductor 31 with a cleaning member, and collects the residual toner. However, when there is little or almost no toner remaining on the surface of the photoconductor, the photoconductor cleaning blade 32 may be omitted.

  The type of the transfer device 35 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. Here, it is assumed that the transfer device 5 is disposed to face the photoconductor 31. The transfer device 35 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the photoconductor 31 to the transfer material conveyance body.

<Example of manufacturing toner for developing electrostatic image>
[Example of production of toner for developing electrostatic image: T1]
<Manufacture of wax emulsion A>
20 parts by weight of paraffin wax (HNP9: Nippon Seiwa Co., Ltd., melting point: 77 ° C.) was added to a 20% by weight aqueous solution of anionic surfactant (Neogen S-20D: sodium dodecylbenzenesulfonate aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “20% An emulsion of paraffin wax (hereinafter abbreviated as “wax emulsion A1”) was prepared by emulsification under high-pressure shearing in addition to 1.44 parts by mass of DBS aqueous solution ”and 1.44 parts by mass of ion-exchanged water. . The number average particle diameter (mn) measured with Nikkiso Microtrack MT3300 was 0.25 μm.

  The melting point of the wax was measured using a DSC-20 manufactured by Seiko Instruments Inc. at a temperature increase rate of 10 ° C./min, and the temperature was the peak apex temperature showing the maximum endotherm in the DSC curve.

<Production of polymer primary particle emulsion B1>
A reactor equipped with a stirrer (three blades), a heating / cooling device, and a raw material / auxiliary charging device was charged with 35.6 parts by mass of the wax emulsion A1 and 283 parts by mass of ion-exchanged water, and nitrogen was stirred. The temperature was raised to 90 ° C. under an air stream. While stirring at a peripheral speed of 2.78 m / s at the tip of the stirring blade, a mixture of [Polymerizable monomers etc.] in Table 1 and [Emulsifier aqueous solution] was added over 5 hours. The time at which the mixture was started to be dropped was defined as “polymerization start”, and 30 minutes after “polymerization start”, [Initiator aqueous solution-1] was added over 4.5 hours in parallel with the above operation. After the addition of the mixture and [Initiator aqueous solution-1] was completed, [Initiator aqueous solution-2] was added over 2 hours. Stirring was further continued after the addition of [Initiator aqueous solution-2], and the internal temperature was maintained at 90 ° C. for 1 hour.

<Table-1>
[Polymerizable monomers, etc.]
Styrene 76.75 parts by weight Butyl acrylate 23.25 parts by weight Acrylic acid 1.5 parts by weight Hexanediol diacrylate 0.7 parts by weight Trichlorobromomethane 1.0 part by weight
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part by mass ion-exchanged water 67.1 parts by mass
[Initiator aqueous solution-1]
8 mass% aqueous hydrogen peroxide solution 15.52 mass parts 8 mass% L (+)-ascorbic acid aqueous solution 15.52 mass parts
[Initiator aqueous solution-2]
8 mass% L (+)-ascorbic acid aqueous solution 14.21 mass parts It cooled after completion | finish of a polymerization reaction, and milky-white polymer primary particle emulsion B1 was obtained. The volume average particle diameter (mv) measured using Microtrac UPA was 0.27 μm, and the solid content concentration was 20.4% by mass.

<Production of polymer primary particle emulsion B2>
1.78 parts by weight of 20% DBS aqueous solution and 290 parts of ion-exchanged water were charged into a reactor equipped with a stirrer (three blades), a heating / cooling device, and a raw material / auxiliary charging device, and 90 ° C. under a nitrogen stream. The temperature was raised to. While stirring at a peripheral speed of 2.78 m / s at the tip of the stirring blade, [Initiator aqueous solution-3] in <Table-2> was added all at once.

  Thereafter, the mixture of [polymerizable monomers etc.] and [emulsifier aqueous solution] in Table 2 was added over 5 hours while stirring was continued. Moreover, the time which started dripping the said mixture was made into "polymerization start", and [initiator aqueous solution-4] was added over 6 hours from the polymerization start in parallel with said operation. Stirring was further continued after addition of [Initiator aqueous solution-4] was completed, and the internal temperature was maintained at 90 ° C. for 1 hour.

<Table-2>
[Polymerizable monomers, etc.]
Styrene 100.0 parts by mass Acrylic acid 0.5 parts by mass Trichlorobromomethane 0.75 parts by mass
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part by mass ion-exchanged water 66.0 parts by mass
[Initiator aqueous solution-3]
8 mass% hydrogen peroxide aqueous solution 3.2 mass parts 8 mass% L (+)-ascorbic acid aqueous solution 3.2 mass parts
[Initiator aqueous solution-4]
8 mass% hydrogen peroxide aqueous solution 18.9 mass parts 8 mass% L (+)-ascorbic acid aqueous solution 18.9 mass parts It cooled after completion | finish of polymerization reaction, and milky-white polymer primary particle emulsion B2 was obtained. The volume average particle diameter (mv) measured using Microtrac UPA was 0.15 μm, and the solid content concentration was 19.5% by mass.

<Toner particle dispersion>
Using each component of <Table-3>, the following aggregation process (core material aggregation process / shell coating process) / circularization process was performed to obtain a dispersion of toner particles having a core-shell structure. .

<Table-3>
Polymer primary particle emulsion B1 As solid content 92.5 parts by mass Polymer primary particle emulsion B2 As solid content 7.5 parts by weight Colorant (Pigment Yellow 74) Dispersion As colorant solids 6.7 parts by weight 20% DBS Aqueous solution In the core material agglomeration process, the solid content is 0.05 parts by mass.
In the rounding step, the solid content is 6.0 parts by mass, 0.5% by mass aluminum sulfate aqueous solution, and the solid content is 0.2 parts by mass.

○ Core material agglomeration process Polymer primary particle emulsion B1 and 20% DBS aqueous solution are charged into a mixer equipped with a stirrer (double helical blade), heating / cooling device, and raw material / auxiliary charging device, and stirred at an internal temperature of 10 ° C. The mixture was stirred for 5 minutes at a peripheral speed of 0.8 m / s at the blade tip. Subsequently, the peripheral speed at the tip of the stirring blade was increased to 5.1 m / s, and the colorant dispersion was continuously added over 15 minutes and held for 5 minutes.
Thereafter, the internal temperature was raised to 55 ° C. over 74 minutes while maintaining the peripheral speed. Next, this state was maintained for 112 minutes, and when the volume median diameter (Dv50) was measured using a multisizer, it grew to 6.95 μm.

○ Shell coating step Subsequently, the polymer primary particle emulsion B2 was continuously added over 13 minutes, and held as it was for 40 minutes. At this time, the Dv50 of the particles was 7.22 μm.

○ Circularization Step Subsequently, 6 parts by mass of a 20% DBS aqueous solution and 3.5 parts by mass of ion-exchanged water were added over a total of 25 minutes, the temperature was raised to 98 ° C., and then maintained for 27 minutes. Thereafter, the mixture was cooled to 30 ° C. over 58 minutes to obtain a toner particle dispersion. At this time, the particle diameter Dv50 of the toner particles was 7.05 μm, and the average circularity measured using a flow particle image analyzer FPIA-3000 (manufactured by Sysmex Corporation) was 0.970.

<Washing and drying of toner particles>
After the toner particle dispersion liquid is produced by the above method, the toner particle dispersion liquid is filtered using a centrifuge (Peeler Centrefuge HZ: manufactured by Mitsubishi Chemical Corporation) and passing ion-exchanged water 63 times the toner particles. , Washed. Further, the washed toner particles were dried in an atmosphere of 40 ° C. until the water content became 0.2% by mass, to obtain toner mother particles C1.

<External toner addition>
Further, the obtained toner base particles C1 are obtained by stirring and mixing the materials described in <Table 4> at a peripheral speed of 50 m / s at the tip of the stirring blade using a Henschel mixer. T1 was produced.

<Table-4>
Toner base particle C1 100.0 parts by mass silica (primary particle size 12 nm silicon oil treatment) 1.6 parts by mass titania (primary particle size 250 nm alumina treatment) 0.05 mass parts titania (primary particle size 15 nm alkylsilane treatment) 0. 2 parts by mass Hydrotalcite compound 0.05 parts by mass Fatty acid metal salt (Zinc stearate manufactured by Nippon Oil & Fats: MZ-2) 0.30 parts by mass [Toner production example for electrostatic charge development: T2]
In the same production method as that for the electrostatic charge developing toner T1, only the amount of zinc stearate added in the external addition step was changed to 0.20 parts by mass to produce toner T2.

[Electrostatic charge developing toner comparative production example: T3]
In the same production method as that for the electrostatic charge developing toner T1, only the amount of zinc stearate added in the external addition step was changed to 0.15 parts by mass to produce toner T3.
[Electrostatic charge developing toner comparative production example: T4]
In the same production method as that for the electrostatic charge developing toner T1, only the amount of zinc stearate added in the external addition step was changed to 0.03 parts by mass to produce toner T4.

[Electrostatic charge developing toner comparative production example: T5]
In the same production method as the electrostatic charge developing toner T3, the toner T5 was produced by replacing the silicone oil-treated silica in the external addition step with 1.2 parts by mass of TG308F manufactured by Cabot.
[Electrostatic charge developing toner comparative production example: T6]
In the same production method as the electrostatic charge developing toner T5, T6 was produced by changing the addition amount of titania (primary particle size 250 nm alumina treatment) in the external addition step to 0 parts by mass.

[Electrostatic charge developing toner comparative production example: T7]
Toner base particles C2 were produced as described in detail below, except that polymer primary particle emulsions B1 and B2 were prepared in the same manner as electrostatic charge developing toner T6.

<Toner particle dispersion>
Using the following components, toner base particles C2 were produced by carrying out the following aggregation process (core material aggregation process / shell coating process) / circularization process.
Polymer primary particle emulsion B1 As solid content 90.0 parts by weight Polymer primary particle emulsion B2 As solid content 10.0 parts by weight Colorant (Pigment Yellow 74) Dispersion As colorant solid content 5.0 parts by weight 20% DBS In aqueous solution rounding process, 6.0 parts by weight as solid content

○ Core material agglomeration step Polymer primary particle dispersion B1 was charged into a mixer (volume 1000 L, inner diameter 850 mm) equipped with a stirrer (double helical blade), heating / cooling device, and raw material / auxiliary charging device, and 20% DBS. 0.05 part of an aqueous solution was added and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Subsequently, the mixture was stirred at 101 rpm at an internal temperature of 10 ° C., and 0.12 part of K2SO4 as a 5% by mass aqueous solution of potassium sulfate was continuously added over 1 minute, and then the colorant fine particle dispersion was added over 5 minutes. It added continuously and mixed uniformly with the internal temperature of 10 degreeC.

  Thereafter, 0.2 part by weight of a 0.5% by weight aqueous solution of aluminum sulfate was continuously added over 30 minutes, and 0.2 part of demineralized water was added over 30 minutes. The temperature was raised to 54.0 ° C. over 90 minutes. Next, after 30 minutes, the temperature was raised to 1.0 ° C., held at 55.0 ° C., the volume median diameter was measured using a multisizer, and grown to 6.00 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion B2 was continuously added over 15 minutes while maintaining the internal temperature at 55.0 ° C. and the rotation speed of 101 rpm, and held as it was for 60 minutes. At this time, Dv50 of the particles was 6.15 μm.
○ Circularization step Subsequently, the mixture was heated to 90 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as solids) and 0.04 part of water over 30 minutes with the same rotation speed, and then The temperature was raised to 101.5 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.974 over 1.5 hours. Thereafter, the mixture was cooled to 20 ° C. over 50 minutes to obtain a slurry of toner base particles B. At this time, the volume median diameter of the particles is 6.23 μm, the number median diameter is 5.94 μm, the distribution (volume median diameter) / (number median diameter) is 1.071, and the average circularity is 0.978. there were.

<Washing and drying of toner particles>
Using a wet electromagnetic sieve shaker (AS200 / Lecce Co., Ltd.) equipped with a sieve having a mesh size of 24 μm, the entire amount of the resulting slurry is subjected to filtration treatment for the purpose of removing coarse particles in a tank equipped with a stirrer. Once stored. Thereafter, this slurry was subjected to a horizontal centrifuge (HZ40Si type / Mitsubishi Chemical Corporation) equipped with a filter cloth (polyester TR815C, Nakao filter industry / thickness 0.3 mm / air permeability 48 (cc / cm ² / min)). Then, centrifugal dehydration washing was performed under the condition of acceleration 800G. When ion-exchanged water having an electric conductivity of 1 μS / cm was added at a rate not to overflow from the rim at about 50 times the amount of slurry solids, the electric conductivity of the filtrate was 2 μS / cm. Finally, water was thoroughly shaken off, and the cake was recovered with a scraping device.
The cake obtained here was spread on a stainless steel vat so that the height was 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles C2.

<External toner addition>
Further, the obtained toner base particle C2 is obtained by stirring and mixing the materials described in <Table-5> at a peripheral speed of 50 m / s at the tip of the stirring blade using a Henschel mixer. T7 was produced.

<Table-5>
Toner base particle C2 100.0 parts by mass Silica (primary particle size 12 nm, silicon oil treatment) 1.2 parts by mass Titania (primary particle size 15 nm alkylsilane treatment) 0.4 parts by mass Hydrotalcite compound 0.05 parts by mass Fatty acid Metal salt (Zinc stearate made by Nippon Oil & Fats: MZ-2) 0.15 parts by mass [Comparative example of toner for developing electrostatic image: T8]
In the same production method as the electrostatic image developing toner T7, the amount of titania (primary particle size 15 nm alkylsilane treatment) added in the external addition step was replaced with 1 part by mass to produce a toner T8.

<Evaluation>
The toner T1 to T8 obtained as described above is packed in a cartridge, and the length of the cleaning blade for the transfer material conveyance body is 35 cm. HP manufactured by Hewlett Packard Co.
The following items were evaluated using Color LaserJet Enterprise CP5525.

[Evaluation item]
・ Cleanability of cleaning belt for transfer material transporter (CL defect)
-Amount of toner consumed for printing (toner consumption)
・ Abnormal noise (sound) generated between the photoconductor and the photoconductor cleaning blade

[Evaluation method]
-CL failure When the cleaning property of the transfer material transport belt decreases, the toner that could not be removed sufficiently is transferred to the printing paper, so the presence or absence of image failure is visually checked during printing and the cleaning performance is evaluated. did.
A toner consumption cartridge is filled with a predetermined amount of toner, and printing is performed using the printer. The amount of toner consumption (m / P) was calculated from the number of printed sheets P (sheets) and the amount of toner used m (g) that were flown until the display intended to replace the cartridge appeared on the printer.
・ The sounding printer started the printing operation and heard the operation sound until the printing was completed once, and the sounding performance was evaluated from the frequency of occurrence of abnormal noise when this operation was performed 10 times.

[Evaluation criteria]
・ CL defect ○ ・ ・ ・ No image defect due to the transfer material transport body cleaning blade ×× Image defect due to the transfer material transport body cleaning blade ・ Toner consumption ○ ... Toner consumption 0.015 g / Less than sheet Δ: Toner consumption 0.015 g / sheet or more 0.017 g / sheet or less × ... Toner consumption 0.017 g / sheet or more · Sound ○: No abnormal noise Δ ... 1 to 4 times out of 10 times x 5 times or more out of 10 times

  From the above results, compared with Comparative Example 4 and Comparative Example 5 using toner having a particle size smaller than the volume average particle size defined in the present invention, the present invention can suppress the cleaning failure of the transfer material conveyance body. I understand that. In addition, it can be seen that the present invention can suppress the toner consumption as compared with Comparative Example 2 and Comparative Example 3 using a toner less than the amount of the silicone oil-treated silica specified in the present invention. Furthermore, it can be seen that the present invention can satisfactorily suppress noise as compared with Comparative Example 1 using a toner whose amount is less than that of the fatty acid metal salt defined in the present invention. Therefore, by optimizing the content of higher fatty acid metal salt particles and silicone oil-treated silica with respect to toner base particles having a specific volume average particle size, it is possible to suppress poor cleaning on the transfer material conveyance body and to consume toner. It can be seen that the amount can be reduced and noise can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Transfer material conveyance body 2 ... Cleaning blade 3 for transfer material conveyance bodies ... Electrophotographic toner cartridge 4 ... Exposure device 5 ... Transfer device 6 ... Fixing device 61 ... Upper part Fixing member 62... Lower fixing member 31... Electrophotographic photosensitive member 32... Cleaning drum 33 for photosensitive member... Charging device 4. 341 ・ ・ Current tank 342 ・ ・ Agitator 343 ・ Supply roller 344 ・ Development roller 345 ・ Regulating member

Claims (2)

An integrated electrophotographic cartridge comprising an electrophotographic photosensitive member on which a toner image is carried, a toner base particle having a volume average particle size of 6.7 μm to 7.5 μm, and an electrostatic charge image developing toner having an external additive A transfer material transport body that transfers a toner image formed on the electrophotographic photoreceptor, a transfer material transport cleaning member that removes toner remaining on the surface of the transfer material transport body, and a photoconductor In the image forming apparatus including the cleaning blade, the transfer material transport member cleaning member is a cleaning blade, and the length of the transfer material transport member cleaning blade in a major axis direction is not less than 32 cm and not more than 95 cm. An image forming apparatus, wherein the charge image developing toner satisfies both of the following (1) and (2).
(1) 0.15 parts by mass or more and 0.30 parts by mass or less of a higher fatty acid metal salt with respect to 100 parts by mass of the toner base particles (2) Silicone oil treatment is performed on 100 parts by mass of the toner base particles. 1 silica
. 4 parts by weight or more and 1.8 parts by weight or less, and the amount of all external additives used is 1.0 part by weight or more and 2.4 parts by weight or less with respect to 100 parts by weight of the toner base particles. The toner for developing an electrostatic charge image contains hydrotalcite as an external additive.
The image forming apparatus described in 1.

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